HomeMy WebLinkAbout; Agua Hedionda Watershed; Agua Hedionda Watershed Management Plan Part 1; 2008-08-01Fundirzg fo�• this pf�oject has been provided in full oY in part tl�rough an agreement with the State WateY
Resources Control Board. The contents of this document do not necessarily reflect the views and policies
of the State Water Resoirrces Control Board, nor does rnention of t��ade names or commercial products
� constitute endor�sement or recomrner�dation of foi� use. (Gov. Code 7550, 40 CFR 31.20)
Acknowledaements
Tetra Tech would like to thank the following people for their participation in the Watershed Planning
Group and assistance in developing the Agua Hedionda Watershed Management Plan:
Ashford, Meleah
Cerda, Jr., Al
Cinciarelli, Kasey
Clark, Ronie
Clarke, Mary
Clemente, Chiara
Farrell, Sandra
Fiedler, Jan
Fielstra, Cari J.
Gafford, Mike
Gaines, Stephanie
Grim, Mike
Hallock, Ann
Hauser, David
Howes, Mike
Humphrey, Roseanne
Hussey, Diane
Innecken, Shirley
Johuson, Megan
Jones, Jessica
Kay, Isabelle
Koski, Marci L.
LePage, Steve
Mallett, Cynthia
Mattson, Michelle
Munoz, Eric
Nygaard, Diane
O'Kino-O"Neill, Merle
Porter, Mike
Posthumus, Bruce
Snyder, Todd
Spear, Tamara
Strommer, Jayne
Weaver, Nikki
Ashford Engineering, Inc (Watershed Coordinator)
AHLF/ Native American/Luiseno Liaison
Agua Hedionda Lagoon Foundation
California Department of Parks and Recreation
Friends of Hedionda Creek
Regional Water Quality Controi Board, R9
Friends of Hedionda Creek
Resident of Vista
Director, Green Oak Ranch
Hubbs-SeaWorld Research Institute
San Diego County, Department of Planning and Land UseDPLU
City of Carlsbad
Preserve Calavera
City of Carlsbad (Engineering)
Howes Weiler & Associates
City of Carlsbad
Resource Conservation District of Greater San Diego
Southem California Coastal Wetlands Project
Southern Califonlia Wetlauds Recovery Project
Poseidon Resources
UCSD Naturai Reserve Systein
U.S. Fish & Wildlife Service
M-REP Coiisulting
City of Oceanside
Aspen Environmental
Agua Hedionda Lagoon Foundation
Preserve Calavera
Carlsbad Watershed Network
Regional Water Quality Control Board, R9 (Grant Manager)
Regional Water Quality Control Board, 9
County of San Diego, DPLUDepartment of Planning and Land Use
California Department of Fish and Gaine
City of Vista (Project Director)
Discovery Center Director
In addition to the WPG, the following individuals provided additional input for the WMP:
Gibson, Dave Regio11a1 Water Quality Controi Board, R9
Henika, Shelia Cabrillo Power II
Lloyd, David Agua Hedionda Lagoon Found./Cabrillo Power Plant
Spiegelberg, Markus Center for Natural Lands Management
Zoutendyk, David United States Fisll and Wildiife Service Refuges
- Special thanks to the foilowing members of the Technical Advisory Committee who helped establish
assumptions for future land use conditions, comment on draft findings, screen candidate best management
practices and LID scenarios to evaluate in more detail, and provide input on candidate sites for stream
restoration, BMP retrofits, and land acquisition.
Ashford, Meleah
Conley, John
Gaines, Stephanie
Grim, Mike
Hauser, David
Mendosa, Carlos
Snyder, Todd
St. Clair, Ken
Strommer, Jayne
Ashford Engineering, Inc
City of Vista (Planning)
County of San Diego (Department of Planning and Land Use)
City of Carlsbad (Planning)
City of Carlsbad (Engineering)
City of Vista (Engineering)
County of San Diego (Department of Planning and Land Use)
Ciry of San Marcos (Stormwater)
City of Vista (Stormwater)
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Agua Hedionda Watershed Management Plan - Final August 2008
Table of Contents
...
Ac ow edgements ........................................................................................................................ iii
Listof Tables ............................................................................................................................. iv
Listof Figures ...............................................................................................................................v
1 Introduction ........................................................................................................................... 1-1
2 Watershed Characteristics .................................................................................................... 2-1
2.1 Location and Population ...................................................................................................................... 2-1
2.2 Subwatersheds ......................................................................................................................................2-1
2.3 Land Use and Land Cover (Existing and Future) ................................................................................. 2-2
2.3.1 Land Use ............................................................................................................................................ 2-2
2.3.2 Iinpervious Surfaces .......................................................................................................................... 2-6
3 Assessment and Planning Approach ..................................................................................... 3-1
3.1 Mission, Goals, and Objectives ............................................................................................................ 3-1
�f ` 3.2 Establishing Indicators and Assessment Tools ..................................................................................... 3-3
'- . 3.3 Other Evaluation Criteria ..................................................................................................................... 3-7
4 Existing and Future Watershed Conditions .......................................................................... 4-1
4.1 Water Quality Conditions and Trends .................................................................................................. 4-1
4.1.1 Agua Hedionda Water Quality Analysis ............................................................................................ 4-1
4.1.2 Watershed Scenario Modeling ........................................................................................................... 4-2
4.2 Geomorphology Conditions and Trends .............................................................................................. 4-4
4.2.1 Comparison with Hydrologic Modeling Results ................................................................................ 4-6
4.3 Climate Conditions and Trends ............................................................................................................ 4-7
4.4 Habitat Conditions and Trends ............................................................................................................. 4-8
4.4.1 General Habitat Conditions ............................................................................................................... 4-8
4.5 Cultural Resources ..............................................................................................................................4-16
4.6 Priority Watershed Issues ....................................................................................................................4-16
5 Management Building Blocks and Gaps .............................................................................. 5-1
5.1 Key Watershed Manageinent Building Blocks .................................................................................... 5-1
5.2 Baseline Conditions: Gap Assessment ................................................................................................. 5-5
5.3 Summary of Management Gaps and Needs ......................................................................................... 5-9
6 Recommended Watershed Management Opportunities ....................................................... 6-1
6.1 New Development Site Management ................................................................................................... 6-1
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Agua Hedionda Watershed Management Plan - Final
Auqust 2008
6.2 Land Acquisition, Riparian Buffer Restoration, and Wetlands Restoration ........................................ 6-8
6.2.1 Screening Criteria .............................................................................................................................. 6-9
6.2.2 Prioritization .....................................................................................................................................6-11
6.3 Streain Restoration ..............................................................................................................................6-25
6.3.1 Screening Criteria .............................................................................................................................6-25
6.3.2 Prioritization .....................................................................................................................................6-26
6.4 Stormwater BMP Retrofit Projects ......................................................................................................6-31
6.4.1 Screening Criteria .............................................................................................................................6-31
6.5 Monitoring ..........................................................................................................................................6-34
6.5.1 Monitoring Indicators .......................................................................................................................6-35
6.5.2 Existing Monitoring in the Watershed ..............................................................................................6-35
6.5.3 Future WMP Monitoring Recommendations ....................................................................................6-39
6.6 Citizen Stewardship/Public Outreach ..................................................................................................6-41
6.6.1 Collaborative Watershed Council .....................................................................................................6-41
6.6.2 Education of Local Boards to Gain Support for Watershed Management ........................................6-42
6.6.3 Developinent of Citizen Education Materials ...................................................................................6-43
6.6.4 LID Workshops and Training ...........................................................................................................6-44
6.6.5 Annual Awards Program ..................................................................................................................6-44
{ . , 6.6.6 Annual Progress Workshops .............................................................................................................6-44
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' .. 6.6.7 Management Partnerships .................................................................................................................6-44
6.6.8 Data/Infonnation Management Via Website ....................................................................................6-45
6.7 Funding And Sustained Support .........................................................................................................6-45
6.7.1 Grant Prograins .................................................................................................................................6-45
6.7.2 Coordination with Agencies .............................................................................................................6-47
6.73 Mitigation Prograins .........................................................................................................................6-47
6.7.4 Watershed Council Support ..............................................................................................................6-48
6.7.5 Iinplementation .................................................................................................................................6-48
6.8 Recoininended Focus Areas for Management .....................................................................................6-49
7 Implementation ..................................................................................................................... 7-1
7.1 Primary Roles and Responsibilities in Carrying Out the Actions ........................................................ 7-1
7.1.1 New Development Site Management Actions ................................................................................... 7-1
7.1.2 Preservation Actions ......................................................................................................................... 7-3
7.1.3 Riparian Buffer, Wetland and Stream Restoration ............................................................................ 7-4
7.1.4 Stonnwater BMP Retrofit .................................................................................................................. 7-6
7.1.5 Monitoring and Enforcement ............................................................................................................. 7-7
7.1.6 Citizen Stewardship/Public Outreach ................................................................................................ 7-9
7.1.7 Funding and Sustained Support ........................................................................................................7-10
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Hedionda Watershed Management Plan - Final August 2008
7.2 Tiinelines and Milestones ....................................................................................................................7-11
73 Estiinated Costs and Funding ..............................................................................................................7-12
7.4 Estimated Impacts and Benefits ..........................................................................................................7-14
7.4.1 LID Impleinentation Bene�ts ...........................................................................................................7-14
7.4.2 PreservationBenefits ........................................................................................................................7-17
7.4.3 Riparian Buffers Restoration Benefits ..............................................................................................7-18
7.4.4 Wetland Restoration Benefits ...........................................................................................................7-18
7.4.5 Stream Restoration Benefits .............................................................................................................7-19
7.4.6 BMP Retrofit Benefits ......................................................................................................................7-19
7.5 Adaptive approach ..............................................................................................................................7-20
7.6 How the Plan Supports Regional Requirements and Initiatives ..........................................................7-20
7.6. i Local Urban Runoff Management Programs ....................................................................................7-20
7.6.2 MHCP/MSCP and Open Space Plans (Some Jurisdictions) .............................................................7-21
7.63 Carlsbad Watershed Management Plan ............................................................................................7-22
7.6.4 San Diego County IRWMP ..............................................................................................................7-22
7.6.5 RWQCB Basin Plan, WMI, SWRCB NPS Strategic Plan, California Ocean Plan .........................7-23
7.6.6 Agency Plans ....................................................................................................................................7-24
8 References ...........................................................................................................................8-1
;
�� Appendix A.
Appendix B
Summary of Key Federal, State, and Local Regulations Applicable to the
Watershed......................................................................................................... A-1
Revisions to Land Acquisition, Buffer Restoration, and Wetlands
Restoration Scoring Methods ............................................................................B-1
Appendix C. Stream Restoration Concept Sheets ...................................................................C-1
Appendix D. Additional Data Collection and Design for SR-02 ........................................... D-1
Appendix E. BMP Retrofit Concept Sheets ...........................................................................E-1
Appendix F.
Appendix G.
Appendix H.
Appendix I.
Appendix J.
Appendix K.
Appendix L.
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SET Retrofit Analysis Supporting Documentation ........................................... F-1
Management Opporiunity Atlas ....................................................................... G-1
Implementation Actions ................................................................................... H-1
Linking the Agua Hedionda WMP with IRWMP .............................................. I-1
Supporting Analysis for LID Scenarios .............................................................J-1
WPG and Public Review Comments ................................................................ K-1
Stream Buffer Guidelines for New Development and Redevelopment ............L-1
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Agua Hedionda Watershed Management Plan - Final August 2008
F':'
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List of Tables
Table 2-1. Percent of Watershed for Each Land Use Class in 2007 and 2030 ...................................................... 2-3
Table 3-1. Mission, Goals, and Objectives ............................................................................................................ 3-2
Table 3-2. Infrastructure/Development Manageinent Indicators ........................................................................... 3-4
Table 3-3. Habitat Management Indicators ........................................................................................................... 3-5
Table 3-4. Restoration Management Indicators ..................................................................................................... 3-6
Table 3-5. Stewardship Programmatic Indicators .................................................................................................. 3-7
Table 4-1. Percent Change in Average Annual Loading Relative to the Existing Scenario .................................. 4-3
Table 4-2. Vegetation Community Types in Agua Hedionda Watershed ............................................................. 4-9
Table 4-3. Federal and State Endangered and Threatened Species Identified within the Agua Hedionda
Watershed(CNDDB, 2008) ................................................................................................................4-11
Table 4-4. Acreage of Invasive Plant Species Present in the Agua Hedionda Watershed (SELC) ......................4-15
Table 6-1. LID Scenario Land Use Categories ...................................................................................................... 6-7
Table 6-2.
Table 6-3.
Table 6-4.
Table 6-5.
Table 6-6.
Table 6-7.
Table 6-8.
Table 6-9.
Tabie 6-10.
Table 6-11.
Table 6-12.
Tabie 6-13.
Tabie 7-l.
Initial Screening Criteria Selected to Evaluate Land Acquisition, Buffer Restoration, and
Wetlands Restoration Opportunities ...................................................................................................6-10
Land Acquisition and Preservation Top Ranking Opportunities and Conceptual Cost Estimates ......6-14
Buffer Restoration Top Ranking Opportunities and Conceptual Cost Estimates ................................6-19
Wetlands Restoration Top Ranking Opportunities and Conceptual Cost Estimates ...........................6-24
Summary of Stream Restoration Opportunities ..................................................................................6-29
Streain Restoration Opportunity Conceptual Cost Estimates ..............................................................6-30
Public-Owned Parceis Located within Priority Subwatersheds ..........................................................6-33
Drainage Area and BMP Retrofit Descriptions ...................................................................................6-34
Monitoring Indicators for the Agua Hedionda Watershed ..................................................................6-35
Parameters Collected at the Mass Loading Station (based on 2007 Order) ........................................6-37
Content and Goals for Educating Local Boards ..................................................................................6-43
WMP Partnership Opportunities .........................................................................................................6-45
StormwaterRetrofit Costs ...................................................................................................................7-13
Table 7-2. Medium Density Residential LID Benefits .........................................................................................7-15
Table 7-3. Multifainily Residential LID Benefits .................................................................................................7-15
Table 7-4. Commercial Development LID Benefits .............................................................................................7-15
Table 7-5
Table 7-6.
Table 7-7
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Industrial Development LID Benefits .................................................................................................7-16
Open Space Preservation Benefits ......................................................................................................7-18
Percent Annual Pollutant Load Reductions for Each Retrofit Site ......................................................7-19
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Agua Hedionda Watershed Management Plan - Final August 2008
List of Figures
Figure 2-1. Agua Hedionda Watershed ................................................................................................................... 2-1
Figure 2-2. Map of Agua Hedionda Model Subwatersheds ................................................................................... 2-2
Figure 2-3. Existing (2007) Land Use in the Agua Hedionda Watershed ............................................................... 2-4
Figure 2-4. Estimated Future (2030) Land Use in the Agua Hedionda Watershed ................................................ 2-5
Figure 2-5. Percent Impervious Surface Cover for Each Subwatershed ................................................................. 2-7
Figure 4-l. Priority Subwatersheds with Highest Existing Runoff Volume and Pollutant Loading ....................... 4-4
Figure 4-2. An Incised and Widening (with recent shunping) Reach of Agua Hedionda Creek ............................ 4-5
Figure 4-3. Channel Analysis in Lower Agua Hedionda Creek .............................................................................. 4-6
Figure 4-4. Changes in Hydrologic Metric (TQ11ted1) from Predevelopment to Existing .......................................... 4-7
Figure 4-5. Vegetation Coinmunities Available in the Watershed ......................................................................... 4-9
Figure 4-6. View of Agua Hedionda Lagoon ........................................................................................................4-12
Figure 4-7. Invasive Plant Species Present in the Watershed ................................................................................4-16
Figure 6-1. Slope Class for Developable Land ....................................................................................................... 6-5
Figure 6-2. Soil Hydrologic Group for Developable Land ..................................................................................... 6-6
Figure 6-3. View into the headwater area of the Buena Creek watershed as seen from Hardell Lane.
(Photo courtesy of M. Ashford, Ashford Engineering, Inc.) ...............................................................6-11
Figure 6-4. Existing Natural Riparian Habitat — Agua Hedionda Creek (Reach 17) .............................................6-12
Figure 6-5. Buffer Restoration Opportunities ........................................................................................................6-18
Figure 6-6. Wetlands Restoration Opportunities ...................................................................................................6-23
Figure 6-7. Stream Restoration Opportunities .......................................................................................................6-27
Figure 6-8. Priority BMP Retrofit Opportunities (tmtreated areas in priority subwatersheds are shaded
orange/yellow) ....................................................................................................................................6-32
Figtue 6-9. Map of TMDL Monitoring Sites .........................................................................................................6-38
Figure 6-10. Monitoring Stations in the Agua Hedionda Watershed .......................................................................6-40
Figure 6-1 l. Headwaters Focus Area (This focus area contains a large area of land acquisition opportunity
that is not shown due to the sensitive nature of these opportunities.) .................................................6-51
Figure 6-12. Mainstem Focus Area (Land acquisition opportunities are not shown.) .............................................6-55
Figure 6-13. Lagoon Focus Area (Land acquisition opportunities are not shown.) .................................................6-57
Figure 7-1. Projected Hydrographs for Basic LID and Enhanced LID Scenarios for Multifamily
Developinent.......................................................................................................................................7-17
Q r�rear�ai
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Agua Hedionda Watershed Management Plan - Final August 2008
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Agua Hedionda Watershed Management Plan — Final August 2008
Acronyms
ACOE — Army Corps of Engineers
BIA — Building Industry Association
BMP — Best Management Practice
CDFG — California Department of Fish and Game
CEQA — California Environmental Quality Act
CRAM — California Rapid Assessment Method
DEM — Digital Elevation Model
DWR — California Department of Water Resources
EDD — Extended Dry Detention
EMCs — event mean concentrations
HMPs — Habitat Management Plans
IRWMP — Integrated Regional Water Management Plan
LID — Low Impact Development
LSPC — Loading Simulation Program C++
���� JURMPs — Jurisdictional Urban Runoff Management Programs
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MLPA — 1999 Marine Life Protection Act
MM — Management Measures
MP — Management Practices
MPA — Marine Protected Area
NEPA — National Environmental Policy Act
NGOs — Non-governmental Organizations
PAMA — Pre-approved Mitigation Areas
RWQCB — San Diego Regional Water Qualiry Board
SANDAG — San Diego Area Council of Govenlments
SDG&E — San Diego Gas & Electric
SELC — Sau Elijo Lagoon Conservancy
SET — Site Evaluation Tool
SSO — Sanitary Sewer Overflows
TAC — Technical Advisory Committee
TMDL — Total Maximum Daily Loads
TSS — Total Suspended Solids
USEPA — U.S. Environmental Protection Agency
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Agua Hedionda Watershed Management Plan — Final August 2008
WDRs — Waste Discharge Requirements
WMP — Watershed Management Plan
WPG — Watershed Planning Group
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viii
Agua Hedionda Wafershed Managemen[ P/an - Fina/ A�gust 2008
ua Hedionda WMP Executive Summa
WFiere is the Agua Hedionda watersFied?
'1-hc Agua 1-Icdionda watcrshcd is loca�cd i� soWhcrn California, about 35 milcs vorth ofdowntown Sav
Diegu. Tlac watcrshed di.�ins i 1 syuace mles o1']and and includcs por[iuns o£thc cit3as o£Carlsl ad.
V ista_ Occansidq and San Marcos. and chc u orporatcd Counry of San Dicgo- Thc waic�shcd con[ai��s
approxima[cIy 37 lincar miics of �trc-ams most of which are still natwzl or carthcn bouumcd channcls.
Thc wstcrshcd tcrminatcs at thc Agua 14cdionda Lagoon. an important culnirnl, c �nd
mrvironmcntal resourcc that provi ics critical habiiat lor migratory and residcnt birds andcfish. Thc la�.00n
sc�e�s as nmsery habStat £or wnuncreSally a��d recrcutlonally sfgnfFcan� comtal und residcnt spcucs.
Why does the Agua Hediontla watershed need a management plan?
Signs ofdcgradation a vidcnt tM1roughout thc watoshcd. and signlflcant loss ofnatural habitat a�oss
all ccoeys�emx has uccun�id. In addition. largc ainas with high qualiry habi�a� in the upper wa�o�rohed a
planncd For dcvdopmcnt_ To nddress [hcsc avd othcr conccrns. ihc local stakcholdcrs havc prcparcd this
Watersheci Man��ement Plan (WMP) to "Preacrve, resloro and enhxince the wa�crshed's natural IuocGons
and Tcaturas." TM1cy r cognfzc tliat n hcalthy wutcrshcd is onc that provSdcs wildGFc I�ubitat, dcan waccr.
xcnic bcuury. and othcr bcncfits.
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Hedionda Watershetl Manaoement P/an — Final Auousf 2008
What are tFie priority issues in th¢ watershed?
A��umbc-r oF prlon�y Issuce vmcr_ed from Oic asscssmcni o£watersl�ed wnditions and trcnds, including:
� Urban lmnd u. c laas i� � scd o r timc in thc watcrsM1cd, rcplacing agriculturc and natmai opcn
spacc. Fuhvc dcvdopmcnt is cxpcctcd to causc additional impacts to watcr quatity and strcam
slabiliry.
� Thc San �iago Regional Water Quality Board (RWQC6) hae lutcd Agua Hcdfonda Cmck,
L3ucna Crcck, and Agua licdionda Lagoon a n�paircd and not suppo�tiog dcsigna[cd bcncl9cial
usce undcr the Clcan Watcr Act Scc(ion 303(d�).
. Sa-eam chanvel �nodification, lio�n a natural
to imp�ctcd statq lias bccn obscrvcd
throughoul tFc watcrshcd. Typical impacts
�clude habitat dcgradation and channal and
bank o-osion (scc photo m thc righc).
. "fhc nialc rity o{���-tland and riparian habitat
in thc wutcrshed has eiil�cr bccn cleurcd o�
dcvclopcd. Thcl�rgcs[cxpanscs o{
unpro�cc�cd habiiat. L oth ripariun and
upland, c ist in tl�c upper watcrshcd, wliilc
thc largcst pro[cctcd arcas occw m Uic lowcr
wato5hcd.
. Predicted clima�e diange may prewvt a
challcngc to planning long-tcrm
manngmnent in Oic Agua Hedionda Fallen Tr¢es Du¢ to Bank Erosion
watcrshcd. SM1ifls i catM1cr yaucrns niay
. vcdii -nt loading, channG crosion, and othcr strcsso�s that alrcady have an impact on
wat�rshcd Cunetions. Climate change maY �Iso endaneer exisGng hnbitat ancl wuLd prascnt
�nc,�uiscd M1azsvds to both hunian and a�un�al Ii£c in thc watcrshcd.
What is the Agua Hedionda Watershed Management Plan?
Thc Agua Ncdionda WMP providcs o niprchcnsivc, s� cntificalty-bascd plan for prescrving, restoring.
a�id cnhancing watcrshcd func�ions and� zing Fumrc dcgradacion. "I'hc WMP asscsses past, prc. nt.
�nd fu�uiv H•atcrshcd c ncG�ions and idcnGtica��n cnt nccds thmugliout tM1c watcrshcd, c .v-idcring
ihc c n�plcx rclationships anioi�g dli{crcnt watcrshcd proccsscs_ A.. thc watcrshcd faccs additional stress
from�dcvcloP�»cnt, thc W"MP P�'�viAcs a foundation for succcssllilty addre�sing both pust dcgradaGon and
1Lture svcsscs, and as turthcr watcrshcd-rclatcd r�Wations o adoptcd, tM1c WMP �uidcs dcci.ion
makcrs towards �hc niost bcncflcial n�anagemrnc praccicw for a hcalthy watcrshcd.
Thc stakchuldcis dwclopcd thc lolluwing noals ihat f nncd thc basis for thc plun:
I. Dcsign land usc and infi'�slruc�ure so as tu minimize impacts on tha watcrshcd.
2. Protroq restorc and cvLzancc habl[at in thc w�atcrshcd.
3. Rcstorc watcrshcd tiustions. I sluding hydrologY, watcr qualiry, and habitat, using a balanccd
approadi �hxt n�ini�nizes ncgat�ivc iinpacte.
4. Sopyort cti�npliancc wiLh rcgional, statq and fcdcral rcguletory rcquircnic��ts.
S Incrcas and stcw�vdship wlthin thc wamrshcd. including cncouraging policymxkcrs �o
dcvclop policics that supP��'t a hcalihY watcrs-hcd.
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Agua Hedionda Watershed Managemen[ P/an - Fina/ Augusf 2008
What does tFie plan recommendl
'I'he WMP rccon�vncnds mana€�����^�.ctions to address priority issucs, build upon cuv-cnt managenicnt
cYY'orts and r solvc c isting o �agcmcnt gaps. Tl�csc actions e c priorlKzcd bas-cd on l�ow wcLl cacF
opportunity will convibutc to�tho WMP goals and obJcctivcs Watcrshcd modd raWts. C:coS�'aphic
Informalion Systems (GIS) anatysis, and tTeld observalion were among Ihe tools used w priodtize the
n�ost pron�ising opportunitics. Thc typcs oFn�anagcv�ant actions a�c su�r�mm �md bdow.
� Ncw �)evclop�nent Site Managcnicnt Ncw AcvcloP�»�nt has a significssnt potcntial io
cxaccrbatc c inting watcrshcd impacts, o- crcatc n rclaGvcty u mpactcd svcams.
IJcvGopm nt can i - c pollutant louding retcs i runoff,�and can also increase Ihe Gcqucnty
and duration of erosivs tlows in strean� channels Appropriate sile �nanage� nt c� � yartially o
n R�1Ly �n9[igatc dcvcbpnicn� unyacts, dcpcnding to a largc dcgrcc on how aggcssivcly thcy
are implemcnted. "fFe WMP rccommo�ds implcmonting watershed-specifc low impact
devcloyment (LlD) �echniques I'or stumiwatcr nuinagemenL fncluding reducGon of Impervious
urfac sv-can� buffcr policics. and tl�c i ofsvuctural stom�watcr i nagcment practiccs
(ex�ended dcxention Cacilitics� grass swales_ and penncablc pa�en�enl�)�
1'reservation and Ripar n 6uffer and
Wcilan`Is Rcstoration: �Ijand acquisition ssni
pr�. -valfon prc, ents rc�niining. nawrel a �..
irom �bcin� dcvdopcd or iuturbcd: ihis typo
of managcmcnt also maintains thc existing
yuality of �hc natural a s �hrouah
stcwaMship activitics, such as i vasivc spccic�
cuntroL Ripa�i�n bulicr res�oratioii crcaic.
iai3vc rip�ar , vcgctation nlone strcams.
Watlunds �c�lor��ion i -cstablishcs wcllen�d
c
nyd�iosv :,��d ���������, .�i,� >>;.�or��-
wctlands hevc bccn impacccd or dcatroycJ_
SpeciGcaOy, ihe wMP rccommcuds �hc
Pollowiog high prbaty ectlo�is:
o Land acc�uisiGon and presovm[ion
o�porcuniiics including 33'1 �cres in
total.
0 2� bufFcr restoration opportunitics ranging fro�n about 02 to 29 acres and including 129
amcs m total_
0 12 [op ranking wctlan 1 res[o.ration oi>Por[miities ranKing li"om abou� 02 to 21 acres and
u�cluding 4� av�c� �n total.
Thcsc oyporamitics i�dodc stakcholdcr rccommcndcd oppormnicics that providc a strong link lo
thc WPG's goals and objcctivc.. '1'hcsc and manY additional rccommcudcd opportimitics arc
providcd tu dccision n�akcrs as part of �hc Maoaec�ncnt OpportunSty Databusc, a sprcadshcct tool
dciailin€ thc charac�cristics ot all opporWni�ics considorcd.
� Stream R¢atoraHon: Strcam restoreGon i� volvcs restornng, �hc shapc and Punction of a strcam.
'1'M1c W MP r ndations, i i purticular_ tocus a istalling gradc control srruciu�ns wi�hin a
s[re�m channc�l io xchicvc cquSlfbrium bctwccn scdSmcnt inFlow ancl transport capadty. Thc
WMP r��ommcnds 1 1 svcam resioraeion rcachcs covcring ncarly 30 000 fcct ol su'cam.
� Srormwa[cr BMP Refrotit ProjecCs: The WMP r ommci�ds portions ot'thc wamrshcd whcrc
rctrofits of smrmw¢tcr bcsi m�anagcmcnt yracticcs (I3MPs) mn rcducc impacts f'om dcvclopmcnt.
Omw�roa
llnprotected Na[ural Habi[at in lJppe� Wa[erstied
Agua Hedionda Watershed Management Plan — Final August 2008
- BMP retrofits recommended include extended detention facilities, grass swales, and other
' structural BMPs that are appropriate for the watershed. Six demonstration BMP retrofits are
identified that can support the above stream restoration oppartunities.
• Monitoring: Once WMP implementation has begun, a coordinated monitoring program is
recommended for water quality, land use change and treatment, restoration, and retrofits.
Specific tracking indicators identified by the WPG can be integrated with existing monitoring
requirements under programs such as the MS4 permit and the MHCP and MSCP programs.
• Citizen Stewardship/Public Outreach: The WMP recommends a comprehensive watershed
iinplementation and stewardship effort led by a collaborative watershed council. Recommended
outreach efforts include education for local boards, educationai materials, technical and policy-
oriented workshops and programs, and management partnerships.
• Funding and Sustained Support: Securing and maintaining stable and diverse funding for the
WMP will be an important, ongoing effort. The WMP discusses options for funding and
sustained support that are most applicable to the watershed.
• Focus Areas: Three areas in the watershed are highlighted in the plan where management
opportunities can be implemented together to achieve cumulative and potentially greater
watershed benefits.
How will the plan be implemented?
Implementation of the WMP will depend on all stakeholders taking an active role, though the roles will
vary greatly by action. The WMP outlines the primary roles and responsibilities of stakeholders in
carrying out the recommended actions. Implementation timelines and inilestones are designated, potential
funding sources are listed, and costs are estimated. Detailed lists of implementation actions are provided
- to facilitate leadership and coordination among stakeholders. It is highly recommended that one of the
first steps toward implementation is the development of a formal Watershed Council consisting of
members of the local jurisdictions with land use authority. One key aspect of implementatiou will be
collaboration with regional management efforts and ageilcies. Mai1y local and regional plans are
identified iu the WMP that relate closely to the Agua Hedionda WMP.
Watershed Inanagement is ongoing work that inust respond and adapt to changing conditions. The WMP
recoinmends several procedures or actions that enable this adaptive approach: long-tenn inonitoring,
inanagement indicators for plan performance evaluation, and a Watershed Council that can make plan
updates.
What are the benefits of plan implementation?
The recommended management opportunities will provide a ntunber of benefits to the watershed. By
addressing the goals and objectives of the pian, these opportunities will work toward preserving,
restoring, and enhancing the Agua Hedionda watershed's natural functions and features. The WMP
describes the specific benefits of all management types and provides quantitative estimates of benefits for
low iinpact development, preseivation, and BMP retrofits.
New development and redevelopment site management will provide reductions in future pollutant loading
and hydrology impacts. Watershed modeling indicates that if certain land conversion (e.g., from
agricultural to LID development) is realized, basic low impact development (LID) techniques and certain
BMPs are impleinented for future developinent and redevelopment, aild land preseivation is achieved,
communities in the watershed should be able to "hold the line" on pollutant loading and peak discharge.
Implementing enhanced LID techniques would achieve even greater cumulative benefits in the watershed.
� ��
ES-4
10��F1GFT(-�Ci9�/�FTiEZ.2aii�i/JF_]i�� _rR.TRCii i i a
Lxnd � cquisStion a id pre. vation c. n have a eiguificum inipact on localizcd stream watcr quality,
sU-cambank scability, and+habitat divcrsity. In tandcm witM1 thc othcr WMP actions, presc�vaiion can also
heLp restore waler qualiry and bydroiogy funcLions on a watc�shcd scalc.
Riparian buffcr restoration is an i�nporiai�< <ool in thc protcction and restoraiion of waiw'shcd funciions.
A staUlq vc�ctcvtcd svcambcank ]s - I�il c mponv-iit o£strvan channel protcction a��d scdin�cnt
reduc�ion. Without vcgctation along,a,strcam. strcambanks c �slough offand mny bcwmc morc
captible to tailure dwing M1igL� llow evenis. Ripvrian buffc•rs �Iso serve as lilters For sedSment and ochcr
pollutants such as nutricncs in rtmol'£fi�om adlnccnt ]and.
"Thc bcncfits ofwctland restoration includc Flow c ntroL � utricnt cycling, nd hahicat divcrsity_ Wctland
o � a
-csturation actiovs cno also streng�hen other WMP aaions, such as buCfer restoration, au-eam restoration,
andland prescrvaGon.
Thc rctroFit 13MPs will providc pollutnnt lond and rt ioff rcductions Eor tlsir rccciving watcrshcds-
Furthcrmorc, lhc BMPs will rcducc s[orm cvcn[ pcssk Flow an 1 runoff vo7umq an iv�por[ant componeni of
miti�ating. risk oF�,comorphic change in streams rcccrving tl�e ru��off.
It i. nportant to no�c that thc r cndcd acifons worlc iogcthcr to acM1iavc grcatcr FuncGonal upliR {or
thc�watc�shcd_ in facc_ thc rccommcndations arc dcsigncd to Icvcragc actions and rt _ 'all
prescrvaGon and res�oraGon bcnclits for thc Agua Hcdiondv wa�crst�ad. CiGzv-�� outraach�and cducaGon
will a�pport thc abovc bcncf its, �nd fundin�, sustaincd support, and n. n3torin= wlll bc csscnGvl for
calizing tfic nn�ltiplc bcnclns :�nd c catin� z� hcal�liY wxtc�:.hcd �hnt providcs Iwbiia�, w��cr cicxn>ing vnd
rc
acsthcGc bcnc�ts ihv� c�n �c m�nagcd �o pmmoie quaGty bcal mmmuniGcs.
Q�w�wo�
(Photo c urtesy of William KloeYzer)
Implementation of the Agua Hetliontla WMP is critical to creating a ti¢althy watershetl that
provides habitat, water cl¢ansing and aestM1etic benefits for local communities.
Agua Hedionda Watershed Management Plan - Final August 2008
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ES-6
Agua Hedionda Watershed Management Plan — Final August 2008
1 Introduction
The Agua Hedionda Watershed Management Plan (WMP) provides a comprehensive, scientifically-based
plan for preseiving, restoring, and enhancing the Agua Hedionda watershed's natural functions and
features. The WMP assesses past, present, and future watershed conditions and identifies management
needs throughout the watershed, considering the complex relationships among different watershed
processes. Governments, organizations, citizens, and other interested stakeholders were involved
throughout the planning process to ensure that the W1VIP reflects local management needs and priorities.
As the watershed faces additional stress from development, the WMP will provide a foundation for
successfully addressing both past and future degradation. As further watershed-related regulations are
adopted, the WMP can be used to guide decision makers towards the inost beneficial management
practices for the watershed.
The Agua Hedionda watershed is located in southern California, about 35 miles north of downtown San
Diego. The watershed drains about 30 square miles of land and includes portions of four municipalities —
Carlsbad, Vista, Oceanside, and Sau Marcos — as well as area in the unincorporated portions of the
County of San Diego. The Agua Hedionda Creek headwaters begin in the San Marcos Mountains in west
central San Diego county. Agua Hedionda Creek flows into the Agua Hedionda Lagoon, which
discharges into the Pacific Ocean. While a few natural and agricultural areas remain, urban development
characterizes much of the watershed.
Prior to the inception of this plan, the Agua Hedionda watershed had experienced significant signs of
degradation. Fallen trees in stream chamlels were among the most evident signs that rapid urban growth
was severely impacting stream channel stability. Monitoring iudicated that water quality in the streams
had significantly degraded. To address these and other concenls, the City of Vista, in cooperation with
� the Carlsbad Watershed Network, received a grant from the State Water Resources Connol Board to
develop a plan to manage and restore the watershed. The purpose of the Agua Hedionda Watershed
Management Plan (WMP) is to provide a comprehensive plan to restore watershed functions and
minimize future degradation.
The Agua Hedionda WMP was developed using a muitifaceted approach, which integrated stakeholder
involvement, science, engineering, and feasibility evaluation. Goals, management objectives, indicators,
and benchmarks were used in the assessment of conditions and evaluation of management strategies and
opportunities; these accountability methods can also be used to evaluate success of the Plan.
Development of this plan included several types of public participation. A watershed coordinator was
hired to coordinate the public outreach. The Watershed Plamling Group (WPG) — with representatives
from local and state governments, federal agencies, environmental organizations, and local citizens — was
formed to provide input and make recoininendations throughout development oi the management plan.
The Technical Advisory Coininittee (TAC) helped establish assumptions for future land use conditions,
comment on draft findings, screen candidate Best Management Practices (BMPs) and Low Impact
Development (LID) scenarios to evaluate in more detail, and provide input on candidate sites for stream
restoration, BMP retrofits, aud land acquisition. Outreach meetings were lield with local governments,
and project reports were posted on a project website to provide wider public access to materials. Public
corrunents were received on the draft plan, and responses to these comments are docuinented in Appendix
K.
Early in the process, Tetra Tech worked with the WPG to develop the following goals for the plan:
l. Design land use and infrastructure so as to minimize impacts on the watershed.
2. Protect, restore and enhance habitat in the watershed.
Q rrrw►re�
1-1
Agua Hedionda Watershed Management Plan — Final August 2008
Restore watershed functions, including hydrology, water quality, and habitat, using a balanced
approach that minimizes negative impacts.
4. Support compiiance with regional, state, and federal regulatory requirements.
5. Increase awareness and stewardship within the watershed, including encouraging policy inakers
to develop policies that support a healthy watershed.
Following the WPG's initial meetings, Tetra Tech conducted field reconnaissance, stream
characterization, geomorphic analysis, data analysis, and watershed modeling to assess the current and
future conditions in the watershed. Preliminary indicators were selected to measure the achievement of
the goals and objectives. Then, the WPG finalized its goals, objectives, and indicators, and Tetra Tech
used these indicators to identify management opporiunities that would best achieve the WPG's goals and
objectives. Tetra Tech produced the following reports that document these assessments in detail:
• Water Quality Analysis and Recommendations Report (Tetra Tech, 2007)
• Watershed Acquisition and Restoration Opportunity Report (Tetra Tech, 2008a)
• Watershed Modeling and Geomorphic Analysis Report (Tetra Tech, 2008b)
• Bioengineering Management and Implementation Report (Tetra Tech, 2008c)
These reports are available from the WMP website (http://www.carlsbadwatershednetwork.org/AH-
WMP.html) or through the City of Vista.
Rather than duplicate this documentation, the WMP draws upon the conclusions of these reports to
recommend an approach for addressing priority watershed issues and achieving the WPG's goals. The
Management Opportunity Database, a spreadsheet tool that contains information for all parcel or site-
k= based opportullities, will be provided to decision makers.
The recommendations of the Agua Hedionda WMP represent a geographically focused, comprehensive
watershed plaiming effort. The plan considers existing and future resource conditions, key watershed
processes, and priority watershed issues. Current regulations and other policies are evaluated as potential
building blocks for the plan recommendations. The goals and objectives developed by stakeholders in the
WPG form the foundation for the identification of manageinent opportunities. The plan presents
management measures for achieving and sustaining ineasurable water quality improvements and
recormnends focus areas where opportunities will complement each other and lead to greater
improvement in watershed functions. Finally, strategies are provided to help facilitate implementation of
plan recommendations which include implementation responsibilities and timelines.
(� rrTw►�
l=J 1-2
Agua Hedionda Wafe�shed Management P/an - Fina/ August 2008
2 Watershed Characteristics
2.l LOCATION AND POPl1LATION
The Agua I-Icdionda wiiorshcd is locatcd in San Oicgo Counry and wi[hin [he Carlsbad Hydrologic U��it.
Tt is approxi �atcly 20, 175 a .v- (3 LS mi') ai�d u di�idcd fnto two subarcas tha Bucna hydrologio
subarea (904�32) in thc upper�watcrshcd and Loe Monos hydrologic subarca (90431) in ihc lower
watarshcd (FGgura 2-1 )- Thc watcrshed 9ndudcs portions oF f ur n�unfeipaliGcs. C�rlsbad, Vfsta,
OccanGidq and San Marcos, a. wcll as arca In thc u o�poratcd porGons oftls Cnunry oi San Dicgo.
These diffemnl jurisdiciions arc es[imatcd to havc a�total poPulation ofabout 65,000 people living in tfie
wa[crsFcd (CV✓N, 300R).
Thc watcrshcd c>ntaius apyroximatcly ;� lu�car �n3les oFstresn� includin� Agua Ilcdionda. Ron�an, Li[tic
Encinas. La Mirada, Calavcra, antl Bucna caccks and scvcral unnamcd tribirtarics. It also includes tfircc
sfgniticant stan ii��g bodies oP watar: tl�e Agua Hcdion 1a Laooun, Lalcc Celav �nd Mzwrkle Rese�voir
(a covcrcd watcr storagc F dlity). Major transportavon corddors includc Intcrstacc 5, Statc Routc �X, �i�c
Pacific Coast Highway, and Ui �n S�nta Fc Railroa 1.
2.2 SUBWATERSHEDS
Thc A�,ua Hcdionda watcrshcd was Aividcd inlo smallcr units. or subwalcisheds, lo Providc a common
basfs for asscssmcnt zind m��iagcmcnt rc,commcndations. Thc subwatcrshcd dGincaGon for Agua
�
Figure 2-'1. Agua Hedionda Watershed
Agua Hedionda Wate�shed Management P/an - Fina/ August 2008
Hedionda i derived liom � 10-�netcrresolution digital elevalion mudel (DEM) Itom the NaGonal
1=lcvation CJatasct. Boundarics w iod3Picd u ing thc n cipai storm s stworks. 2-foot vontour
topographY IaY�=rs. and acrial im�gcs��Acco�alinglY- 29 sub�watershcds p�o[ including thc "bcadi„
watarshad, modal 1� 999) wcro dclinca�cd with an uscra�c ei�c. ol' 1.1 m�- cuvaring a tot-al a�ca oY'31 nu
( Figurc 2-1 ).
2.3 LAND USE AND LAND COVER �EXISTING AND FUTURE�
2.3.1 Land Use
Land use can bc a niajor fo�roc bchind w'atcrshed heal�h �nd degradation. In n�ost casas, land devclopnicnt
will i c[hc volun�q £-cqucncy and n�a� �3[udc ot �zino{t within Hic �uHtcrshcd tM1us Icading to
incronscd�pollu[ant bads anA physical impacis co strcav� channda Therefore_ consider�tion oCexistin�
an 1 futurc land usc pattcrns with3n thc watcrshcd is an i��tceral part o£a watcrshcd m.�nagcmcnt plan.
Currcnt (dcflncd as ycnr 200�) and planncd lend i c(dcfincd as ycac 2030) inf rniation w obtaincd
f'om the San Oicgo Area Council ofGovcrnn�cnu�(SANOAG). SANIJAG has updated thc la��d i
luycrs c�nGnuousty s 2000 u lal pM1otography, Hs County Asscssor Mastcr Propoty Rccords
lilc_ nnd o�her ancilla�y�infi�rn�acion� Thc planocd I2nd use da�a w c derived IYoin the Series 1 1 2egio al
Growt6 Forccast u. ing cach n cipaiiry's n astcr dcvclop�ncnt plans. Slncc cacF juri.s-diction has its ow��
individu�lizcd way of wtcgori�ing its Futurc l�nd usc dosigiin�ions, an �ggrcgalc pl�nncd land use codc
was dcvmcd.
O m��.
Figur¢ 2-2. Map of Agua H¢dionda Mod¢I Subwat¢rshetls
Hedionda Watershed Management Plan — Final August 2008
-> Both SANDAG GIS coverages (both current and planned land use) were modified using GIS parcel data
to allow for a finer resolution of residential categories based on lot size. Additionally, future land use was
modified based on feedback from municipalities on expected changes in under and undeveloped land uses
froin the existing (2007) condition. SANDAG classifications were grouped into a smaller number of
categories for subsequent modeling applicatious (Tetra Tech, 2008b).
In 2007, residential areas covered nearly as much area in the watershed (34 perceut) as the categories of
agriculture and open spaces (38 percent) combined (Table 2-1). By this time residential developments
had spread into the central and upper watershed, bringing human influences into closer contact with
streams and displacing agriculture and open spaces (Figure 2-3). In fact, agricultural lands had already
decreased 55 percent since 19861evels (Tetra Tech, 2007). Most of the areas categorized as "transitional"
before 2007 had been developed into residential and industrial spaces.
As noted in the 2030 Regional Growth Forecast for the San Diego Region (SANDAG, 2005), the
watershed is intended to become primarily residential (46 percent total, with 32 percent as Very Low-,
Low-, Medium-Deusity Residential and Single Family Multiple Units, and 14 percent considered
Multiple Family/High Density Residential), warehouse, industrial and transportation (22 percent), and
open space (19 percent) (Table 2-1). Nearly all current agricultural land is planned for development,
while it is projected that open space will be reduced 33 percent from 2007 levels (Figure 2-4). Although
the land use plans have provided for open space buffers along many of the streams in the lower portion of
the watershed, the vast majority of the upper watershed shows development adjacent to stream corridors.
Table 2-1. Percent of Watershed for Each Land Use Class in 2007 and 2030
Area - 2007 Area -2030
LULC Description (%o) (%)
Agriculture 8% 0%
Heavy Commercial 1 % 3%
High Density Residential (< 0.25 ac) 8% 8%
Low Density Residential (0.5 — 1 ac) 6% 10%
Lt. Commercial/Office/Institutional 4% 5%
Medium Density Residential (0.25 — 0.5 ac) 5% 12%
Multi-Family Residential 4% 6%
Open Space 29% 19%
Open/Recreation 1 % 2°/o
Parks/Recreation 2% 2%
Single Family Multiple Units 2% 2%
Transitional 0% 0%
Very Low Density Residential (> 1 ac) 9% 8°/o
Warehouse/IndustriallTransportation 20% 22%
Water 2% 2%
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Agua Hedionda Watershed Management Plan — Final August 2008
_ 2.3.2 Impervious Surfaces
Urbanization has profound influences on watershed health. As land is converted to rooftops, roads, and
parking lots, impervious surface area increases leading to increased storm runoff while less surface water
is able to infiltrate. These increases in impervious surface lead to greater volume, frequency and
magnitude of runoff within the watershed. The Center for Watershed Protection Impervious Cover Modei
(CWP, 2007a) indicates that certain zones of stream quality exist, most notably at about 10 percent
impervious cover, where sensitive stream elements (e.g., sensitive aquatic species, excellent habitat
structure, and excellelzt water quality) begin to become lost from the system. A second threshold appears
to exist at around 25 to 30 percent impervious cover, where most indicators of stream quality consistently
shift to a poor condition (e.g., diminished aquatic diversity, water quality, and habitat scores). However,
these categories are based heavily upon mid-Atlantic and Puget Sound research and may be less
applicable to Southern California watersheds.
The 2001 National Land Cover Data (30-meter resolution) was used to assess trends in imperviousness
throughout the watershed. The watershed upstream of the lagoon has an average imperviousness of about
29 percent (32 percent if ineasuring froin the lagoon outlet).' The upper portion of the watershed
generally has a lower percentage of impervious surfaces than the lower watershed. Pockets of low
imperviousness are present in the central watershed, especially along the lower portion of Calavera Creek
(see Subwatershed #1008 in Figure 2-5). The intensely developed areas just to the north and south of the
Agua Hedionda lagoon (Subwatersheds #1001 and #1028) have percentages well above 50 percent
(Figure 2-5).
It is important to note that conditions within a stream segment are influenced by the entire upstream
contributiug area. The stress on any particular reach is a result of cumulative imperviousness and
�� associated runoff upstream of that reach. Iu headwater subwatersheds, imperviousness may not impact
the headwater reaches as severely as downstream subwatersheds that have higher cumulative
iinperviousness. On the other hand, subwatersheds that have relatively low imperviousness within the
irmnediate subwatershed area may experieiice severe impacts from upstreain subwatersheds with high
cumulative imperviousuess.
� In the main stem of Agua Hedionda Creek in particular, NLCD impervious data is based on reflectance. In
Southern California, it appears to count beaches and other sandy areas as impervious surfaces (which they are not).
Undeveloped areas also have dispersed, bare rock. This is naturaliy disconnected land and should not be considered
impervious. Therefore, this data may overestimate iinperviousness in some parts of the watershed, particularly in
less developed portions.
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Agua Hedionda Watershed Management Plan - Final August 2008
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(� r�rnw�
� -�� 2-8
Agua Hedionda Watershed Management Plan — Final August 2008
3 Assessment and Planning Approach
3.1 MISSION, GOALS, AND OBJECTIVES
To develop the Agua Hedionda WMP, Tetra Tech worked with the City of Vista using a multifaceted
approach, which integrated stakeholder involvement, science, engineering, and feasibility evaluations.
Development of this plan included several types of public participation:
Watershed Planning Group (WPG) — This group was fonned to provide input and inake
recommendations throughout development of the management plan. Membership is comprised of
50 citizens and representative groups or organizations in the watershed that have a stake or
interest in the Watershed Management Plan. Ten meetings were held to develop goals and
objectives, review and comment on draft findings, and to develop recommendations for the plan.
In addition, members of the group were trained and participated in the watershed field
reconnaissance and characterization.
• Technicai Advisory Committee (TAC) — This group was comprised of local government technical
advisors from planning and engineering departments (Table A-2). The group helped establish
assumptions for future land use conditions, comment on draft findings, screen candidate BMPs
and LID scenarios to evaluate in more detail, and provide input on candidate sites for stream
restoration, BMP retrofits, and land acquisition.
• Watershed Coordinator — The watershed coordinator solicited, asseinbled and managed the
project stakeholders to inaximize their input to the WMP development. This important role
mailitained the continuity and focus of the various stakeholders, the project team and the funding
k
agency.
Outreach meetings — Meetings were held with local jurisdictions, agencies, and stakeholders,
inciuding the Cities of Carlsbad and Vista Engineering and Planning Departments, County of San
Diego Department of Land Use Planning, California Department of Fish and Game, the US Fish
and Wildlife Seivice, Caiifornia Coastal Commission, California State Lands Commission,
Carisbad Watershed Network, Agua Hedionda Lagoon Foundation, Poseidon Resources, and
Cabrillo Power II.
� Web Distribution — Project information and reports were posted on a project website to provide
wider public access to materials produced by the process.
(http://www.carlsbadwatershednetwork. org/AH-WMP.html)
At its initial meeting, the WPG discussed issues that the plan should address and drafted preliminary
Mission, Goals aud Objectives. The discussion included which beneficial watershed uses were important
to protect and restore. After Tetra Tech reviewed existing studies and water quality data and evaluated
the future conditions highlighted in Section 2, the Goals and Objectives were refiued by the WPG. The
Goals and Objectives (Table 3-1) are a critical part of the watershed management plan providing the basis
for determining what issues need to be managed and how they should be addressed.
Q r�n�w�
3-1
Agua Hedionda Watershed Management Plan - Final August 2008
�
i.
Table 3-1. Mission, Goals, and Objectives
Mission Statement
Preserve, restore and enhance the watershed's natural functions and features.
Goals and Objectives
1. Design land use and infrastructure so as to minimize impacts on the watershed.
a) Design and construct infrastructure projects (e.g., sewer lines) in a manner that minimizes impacts on
watershed functions (i.e., water quality, habitat, and hydrology).
b) Design and construct new developments, recreation areas, etc., in a manner that minimizes impacts on
watershed functions, including minimizing impervious areas.
2. Protect, restore and enhance habitat in the watershed.
a) Protect and expand undeveloped natural areas to protect habitat.
b) Protect, enhance, and restore terrestrial habitat, especially existing vegetation in riparian areas.
c) Provide riparian habitat to improve and maintain wildlife habitat.
d) Provide natural area connectivity to improve and maintain wildlife habitat.
e) Maintain stable streambanks and riparian areas to protect instream aquatic habitat and mature trees.
f) Maintain and protect instream habitat to support native aquatic biology.
g) Maintain and protect lagoon habitat.
3. Restore watershed functions, including hydrotogy, water quality, and habitat, using a balanced approach that
minimizes negative impacts.
a) Restore and protect beneficial watershed functions and uses including
■ Wildlife habitat
■ Recreation
■ Protection from flood damage
b) Design and construct restoration projects to minimize impacts to
• Streambanks
■ Riparian areas
■ Wildlife habitat areas
4. Support compliance with regional, state, and federal regulatory requirements. (While there are many regulatory
requirements, several compliance issues are key to addressing existing impacts and mitigating impacts from
future development, as follows.)
a) The San Diego Regional Water Quality Control Board has listed Aqua Hedionda Creek, Buena Creek,
and Agua Hedionda Lagoon as impaired and not supporting designated beneficial uses under the Clean
Water Act Section 303(d). Future compliance includes
■ Meeting water quality standards for Total Dissolved Solids, Manganese, Selenium, and Sulfates for
Aqua Hedionda Creek;
■ Meeting water quality standards for DDT, Nitrate-Nitrite, and phosphate for Buena Creek.
■ Meeting water quality standards for sediment and bacteria in Agua Hedionda lagoon.
(�j rmea�
� -�� 3-2
Agua Hedionda Watershed Management Plan — Final August 2008
,,
b) The San Diego Regional Water Quality Control Board and local governments in the watershed have
stormwater management requirements for controlling sedimentation and erosion during construction.
Future compliance will require adequate inspection and enforcement.
c) The San Diego Regional Water Quafity Control Board and local governments in the watershed have LID
and stormwater management requirements to control post-construction runoff from new development.
Compliance will require plan review, site inspection, and long-term BMP inspection and maintenance to
ensure BMP requirements are being met.
d) Reduce non-compliance events for water quality objectives and sedimentation and erosion control.
5. /ncrease awareness and stewardship within the watershed, including encouraging policymakers to develop
policies that support a healtny watershed. This includes minimizing impervious area and providing for stream
buffers.
a) Form collaborative Agua Hedionda Watershed Council to sustain long-term watershed
mana ement.
• Determine the most appropriate organization and venue for Council.
■ Hire part- or full-time Watershed Coordinator.
■ Gain support from local political and business leaders.
■ Obtain long-term governance and funding for Watershed Coordinator and Council support.
b) Support adoption and implementation of the Watershed Management Plan as well as
ordinances, regulations, policies, and procedures by local jurisdictions, agencies, and
environmental conservation or anizations.
c) Disseminate information to local governments to support scientifically based, sound decision-
makin .
d) Develop a consistent and comprehensive message for watershed health and actions citizens
can take. Distribute through website, water bills, press releases, brochures, and
resentations.
e) Encourage Low Impact Development (LID) at the new development, redevelopment and
individual homeowner and ro'ect level.
f) Reward good stewardship though an awards program that recognizes project sponsors who
im lement ro rams that reserve and enhance watershed health.
g) Develop partnerships with business, residents, NGOs, Cities, the County, Agencies, schools
and private entities throughout the watershed to leverage opportunities for watershed
stewardshi .
3.2 ESTABLISHING INDICATORS AND ASSESSMENT TOOLS
Indicators are ineasurable or predictable quantities that can be used to assess the current health of the
watershed and to track progress toward meeting watershed goals and objectives. Indicators can be linked
to the natural resource or to program actions. Example natural resource indicators for the objectives listed
above are benthic community, channel morphology, and riparian habitat (e.g., as defined by percent
undisturbed forest within the 100-year floodplain). Example programmatic tracking iudicators include
the number of local governments adopting the WMP or the number of presentations made to local
govermnents on WMP findings. Often, there are multiple indicators associated with a given objective.
Since it is important to evaluate existing conditions as well as predict future conditions, some selected
indicators reflect parameters that can be or have been observed in the field (called observed indicators).
Other selected indicators reflect parameters that can be used in modeling to compare current and future
O r�rRwr�
3-3
Agua Hedionda Watershed Management Plan — Final August 2008
conditions (called predictive indicators), while other indicators are used to track progress in meeting goals
and objectives during plan impleinentation (called tracking indicators). Indicatars were established so
that appropriate tools and methods could be selected to support detailed watershed assessment and
planning. To be capable of evaluating how indicators respond to different management actions, Tetra
Tech developed several assessment tools, including a watershed model, a site-evaluation model, and GIS
analysis. Table 3-2, Table 3-3, and Table 3-4 summarize the iudicators selected, how they are linked to
the management objectives, and the assessment tools used.
Table 3-2. Infrastructure/Development Management Indicators
�,.
Linked to Assessment
Indicator Objectives i Tools/Methods
Water Quality (Modeling of Future Conditions): Relative nutrient, upland 1a, 1b Watershed Model
sediment, and bacteria loading
Water Quality (Observed/measured): 1 a, 1 b N/A (This is a future
tracking indicator for
Instream — Copper, Turbidity, Total Dissolved Solids, Total Suspended use during plan
Solids, Total Phosphorus, Total Nitrogen, Enterococcus, Fecal Coliform, impiementation.)
Pesticides: DDT, diazinon, chlorphyrifos
Lagoon — Total Suspended Solids, Turbidity, Totai Phosphorus, Total
Nitrogen, Enterococcus, and Fecal Coliform
Aquatic Habitat (IBI ratings, benthic bioclass, aquatic habitat index) 1a, 1b Data Analysis
Existing native riparian habitat extent and connectivity (percent land 1 a, 1 b GIS Analysis
cover)
Stream stability 1a, 1b Field
Reconnaissance
Watershed Model
Frequency, magnitude, and duration of extreme high flows 1a, 1b Watershed Model
Flood elevation 1 a, 1 b N/A (This is a future
tracking indicator for
use during plan
implementation.)
Constraints to restoration (qualitative) 1a Field
Reconnaissance
GIS Analysis
Planned road/bridge/culvert construction projects 1a N/A (This is a future
tracking indicator for
use during plan
implementation.)
Planned utility expansion 1a N/A (This is a future
tracking indicator for
use during plan
implementation.)
Percent imperviousness 1 b GIS Analysis
Watershed Model
Q rersw�
3-4
Agua Hedionda Watershed Management Plan - Final August 2008
�` �
�
Linked to Assessment
Indicator Objectives Tools/Methods
Percent of development with LID controls 1 b N/A (This is a future
tracking indicator for
use during plan
implementation.)
Percent of development controlled by BMPs 1 b N/A (This is a future
tracking indicator for
use during plan
implementation.)
Table 3-3. Habitat Management Indicators
Linked to Assessment
Indicator Objectives Tools/Methods
Percent of the watershed in natural area 2007 All GIS Analysis
Percent change in watershed natural area: Tracking indicator for plan
implementation.
Existing terrestrial habitat extent and connectivity (percent land cover) All GIS Analysis
Invasive species extent and status of treatment 2a through 2d GIS Analysis
Existing riparian habitat extent and connectivity (percent land cover 2b, 2c, 2e GIS Analysis
within 100-year floodplain)
MSCP and MHCP priority communities extent All GIS Analysis
Location of priority tree species (i.e., 100-year oaks) along streams 2e GIS Analysis
Stream stability 2e Field
Reconnaissance
Watershed Model
Frequency, magnitude, and duration of extreme high flows 2e, 2f Watershed Model
Aquatic Habitat 2007 2e, 2f Field
Reconnaissance
Aquatic Habitat Future — Tracking for plan implementation
Aquatic Biodiversity 2007 2f GIS Analysis
Aquatic Biodiversity Future — Tracking for plan implementation Data Analysis
Lagoon Habitat Quality 2007 2g GIS Analysis
Lagoon Habitat Quality — Tracking for plan implementation Data Analysis
Unprotected terrestrial habitat extent and connectivity (percent land All GIS Analysis
cover)
Q rrrRwr�
3-5
Agua Hedionda Watershed Management Plan — Final August 2008
Table 3-4. Restoration Management Indicators
Linked to Assessment
Indicator Objectives Tools/Methods
Goai #2 Habitat Indicators 3a, 3b GIS Analysis
Existing recreation areas, including trails and natural areas (location, 3a N/A (This is a future
use, potential future impacts) tracking indicator for
use during plan
implementation.)
Degree of flood control within reach 3a N/A (This is a future
tracking indicator for
use during plan
implementation.)
�~ These iudicators and assessment tools were used to evaluate existing conditions, predevelopment
`" conditions, future conditions, and Low Impact Development and BMP impleinentation.
(� r��nw�cr�
� --� 3-6
Agua Hedionda Watershed Management Plan — Final
Table 3-5. Stewardship Programmatic Indicators
August 2008
Linked to Assessment
Indicator Objectives Tools/Methods
Formation of Agua Hedionda Watershed Council 5a N/A (This is a future
tracking indicator for
use during plan
implementation.)
Securing funds for and contracting with a Watershed Coordinator 5a N/A (This is a future
tracking indicator for
use during plan
impiementation.)
Number of jurisdictions, agencies and local NGOs to adopt, accept or 5b N/A (This is a future
formally recognize WMP as a decision making tool tracking indicator for
use during plan
implementation.)
Number of presentations to local government departments and 5c N/A (This is a future
counciis or boards regarding WMP findings tracking indicator for
use during plan
implementation.)
Development of consistent and comprehensive message for 5d N/A (This is a future
watershed heaith tracking indicator for
use during plan
implementation.)
Number of website postings, mailers, bill inserts, press releases or 5d N/A (This is a future
brochures distributed tracking indicator for
use during plan
implementation.)
Number of LID workshops for new development, redevelopment and 5e N/A (This is a future
individual homeowners tracking indicator for
use during pian
implementation.)
Number of Watershed Steward Awards given to local businesses for 5f N/A (This is a future
implementing pollution reducing practices tracking indicator for
use during plan
implementation.)
Number of partnerships throughout the watershed that are leveraged 5g N/A (This is a future
to expand stewardship efforts or messages tracking indicator for
use during plan
implementation.)
3.3 OTHER EVALUATION CRITERIA
Au effective watershed management plan requires not only sound scientific and engineering analysis; it
also requires cost and feasibility analysis. Therefore, in evaluating different management options,
additional evaluation criteria were used such as:
• Meets multiple objectives
• Relative cost
�
3-7
Agua Hedionda Watershed Management Plan — Final August 2008
• Stakeholder support
• Site feasibility (e.g., site access, utility constraints, etc.)
• Political feasibility
• Administrative feasibility
These criteria are discussed in inore detail in Section 6.
(� r.rs,►�
l=J 3-8
Agua Hedionda Watershed Management Plan — Final August 2008
4 Existing and Future Watershed Conditions
4.1 WATER QUALITY CONDITIONS AND TRENDS
4.1.1 Agua Hedionda Water Quality Analysis
The San Diego Regional Water Quality Board (RWQCB) has listed Agua Hedionda Creek, Buena Creek,
and Agua Hedionda Lagoon as impaired and not supporting designated beneficial uses under the Clean
Water Act Section 303(d). Portions of the Agua Hedionda Creek are impaired for total dissolved solids
(TDS), manganese, selenium, and sulfates. Buena Creek is listed for DDT, nitrate-nitrite, and phosphate.
The lagoon is listed as impaired from excess sediment and bacteria. Though several of the impairments
are attributed to unknown sources, the bacterial and sediment-related impairments have been attributed to
urban runoff and other nonpoint sources. Sediment nonpoint sources may include natural background
sources (i.e., sparse chaparral type cover on undeveloped land), channel erosion, and stoimwater runoff
from construction, post-construction, and agricultural sites. Bacteria nonpoint sources may include
natural background sources (i.e., wildlife), residential irrigation runoff, septic systems, sanitary sewers,
transient encampments, and pet waste. Monitoring is underway to collect sufficient data to develop Total
Maximuin Daily Loads (TMDLs)' for these waterbodies under a separate project.
A general watershed characterization and review of existing data was conducted using available regional
and local datasets and previous assessment reports (Tetra Tech, 2007). The review described both spatial
and temporal trends in the watershed io evaluate current water quality conditions and provide
recoinmendations to best meet existing and future regulatory, pianning and monitoring needs.
The data review suggested that sediment (TSS and turbidity) and bacteria (coliforms and enterococcus)
are the greatest threats to watershed function in the Agua Hedionda watershed. Concentrations of these
constituents exceed water quality objectives the majarity of the time. Moreover, reports of significant
upward trends in TSS, turbidity, and fecal coliform at the wet weather monitoring station (where El
Camino Real crosses Agua Hedionda Creek) suggest the problem is getting worse (Weston, 2007a}.
Turbidity was higher in the receiving water samples, an expected pattern based on the stonn-driven nature
of this parameter. Impairment irom indicator bacteria such as fecal coliform is, however, both a dry and
wet weather problem in the watershed.
While the lack of wet weather monitoring sites inhibits the evaluation of spatial patterns, samples
collected as part of the dry weather monitoring (stonn drains and instreain) show particularly high
bacteria levels in La Mirada Creek, which drains commercial development, as well as Calavera Creek
upstream of Lake Calavera. High salinity (a parameter closely related to TDS) is also found aloiig
Calavera Creek in areas draining residential development, suggesting a human source, although
groundwater is likely the chief contributor to TDS levels throughout the watershed. Composition of TDS
has not been analyzed in these sampies. However, it is not unusual for coastal streams in southenl
California to exhibit elevated TDS due to inineral soils and geology.
While nitrogen does not appear to be a significant tbreat in most of the watershed, the iinpainnent of
Buena Creek combined with the significant upward trend of nitrate (Weston, 2007a) suggest that it could
' A TMDL or Total Maximum Daily Load is a calculation of the maximum amount of a pollutant that a
waterbody can receive and stili meet water quality standards, aud an allocatioll of that amount to the
poliutant's sources.
a��
4-1
Agua Hedionda Watershed Management Plan — Final August 2008
- become a problem in the future. Phosphorus levels in the watershed are a concern as well: concentrations
exceed the Basin Plan WQO and Buena Creek is 303(d)-listed for phosphate. Some potential sources of
nutrients throughout the watershed include fertilized lawns, fertilized agricultural fields, and atmospheric
deposition. Irrigation return flow during dry weather can transport significant amounts of nutrients,
particularly nitrogen, to receiving waters via subsurface flow. During wet weather events, build up of
nitrogen and phosphorus on impervious surfaces from atmospheric deposition and other urban activities is
available for surface runoff.
There is some evidence to suggest that pesticides are a threat in the watershed; however, toxicity tests
have not borne out a persistent impact on the biological community. In addition, Weston (2007a)
observed that the number of pesticide exceedances has decreased since 2002. There is also little
indication that metals present a significant problem for aquatic life in the watershed based on an
evaluation of inetals toxiciry.
Given the lack of evidence for widespread and severe toxicity in the watershed, the poor biological
communiry as seen in biotic integrity indices can likely be attributed to habitat degradation from scour
during storms and sediment transport from both upland and instream sources.
4.1.2 Watershed Scenario Modeling
To support the development of the WMP, a watershed model using the Loading Simulation Program C++
(LSPC) was developed to provide an evaluation of the differences between past and future pollutant
loading conditions relative to existing watershed conditions, and supply additional insights into the
potential hydromodification impacts on the physical integrity of stream channels and habitat. LSPC is a
continuous watershed model supported by U.S. Enviroiunentai Protection Agency (USEPA) and has been
;= used widely throughout Southern Califonlia. The watershed model describes hydrology and pollutant
� loading of Total Nitrogen (TN), Total Phosphorus (TP), sediment, and bacteria (fecal coliform). The
model application is documented in Tetra Tech (2008b).
Evaluation of the following indicators under WMP goals 1 and 2 is supported by the modeling analysis:
water quality in terms of relative nutrient, upland sediment, and bacteria loading; stream stability;
frequency, magnitude, and duration of extreme high stream flows; and percent imperviousness. Analysis
of past, present, and future scenarios is used to guide identification of current areas of degradation and
contributors to impairinent as well as potential threats from future development.
Four scenarios were modeled to evaluate past (predevelopment scenario), present (existing scenario) and
future (future scenario) conditions in the Agua Hedionda watershed.
1. The Predevelopment Scenario models all developed land as open space.
2. The Existing Scenario is based on 20071and use (as of approximately January 1) and contains a
representation of BMP treatment for development that has occu2red since 2001, as well as a small
amount of treatment that occurred before that time.
3. The Future Scenario with the Future BMP treatment. This is based on assumptions about
planned development through 2030 overlaid with current stormwater control requireinents. The
Future with BMPs Scenario also contains nearly 1,000 acres of redevelopment and associated
new treatment planned for by the City of Vista.
4. The Future Scenario without the BMP treatment.
Pollutant loading to the lagoon is a concern due to its impaired status for bacteria and sediment. While
this analysis did not provide the EPA-required TMDL (this will occur later in time under another effort),
it can provide a relative understanding of current and future conditions. In the analysis, the Future
a �rx,►,�cH
4-2
Agua Hedionda Watershed Management Plan — Final August 2008
= Scenario with Future BMPs resuits in loading slightly lower poilutant loads than under the Existing
`� Condition, a desirable result (Table 4-1).
Future development with BMPs as represented in the model is predicted to result in an overall decrease in
sediment, bacteria, and nutrient loading to the lagoon due to three factors: (1) preservation of open space,
(2) the conversion of agricultural land to residential and non-residential development that is treated by
stormwater BMPs, and (3) the redevelopment with associated stormwater BMP treatment of significant
portions of the watershed. The modeling results were sensitive to these changes. In particular, if the
planned redevelopment does not occur as represented in the model scenarios (e.g., without treatlnent as
required by the Order R9-2007-001), the watershed could be at greater risk of degradation. Further, since
the assimilative capacity of the lagoon has not been determined to date, additional reductions beyond
those predicted by this watershed model in the future scenario could be needed.
Trends in poilutant loading in the future throughout the watershed are also driven by development of
agricultural land and redevelopment. Decreases in loading seen here tend to mask any increases that are
� derived from the development of open space even though one-third of open space is plamled for
� development. Overall increases in pollutant loading (at least >1 percent) occur in only a%w
subwatersheds. Most of the area-averaged increases in loading are predicted to occur in the upperinost
portion of the watershed; however it is important to note that the upper subwatersheds have a much lower
existing level of loading compared to other subwatersheds.
The Inodeling results were used to select key areas or priority subwatersheds where watershed
management and improvement projects can be focused. Eight subwatersheds were selected in the
foilowing manner (Figure 4-1). First, subwatersheds tha� ranked in the highest quartile within each of the
selected metrics were selected. Metrics considered were existing unit area loading of fecal coliform,
sediment, TN and TP from the watershed model as well as the hydrologic metric, differeuce between
existing and predevelopment TQ,,,ea,,. The TQ117ea„ metric is the proportion of time that stream flow is above
the annual daily-averaged mean level; the difference between the predevelopment and existing scenario
values provides an indicator of the impact of urbanization on the flow regime or channel
hydromodification. Subwateisheds that occurred in the top quartile of three or more of the selected
metrics were considered high priority for management opportunities, inost importantly BMP retrofits.
Q rrTx,►�
4-3
Table 4-1. Percent Change in Average Annual Loading Relative to the Existing Scenario
Agua Hedionda Wate�shed Management P/an — Fina/ August 2008
pm
�c. �enrsm.
E m�va
Aai
�
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�z
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Figure 4-'I. Priority SubwatersF�eds witFi Highest Existing Runoff Volume antl Pollutant Loading
4.2 GEOMORPHOLOGY CONDITIONS AND TRENDS
C:comorphology rcfcrs to �hc study o{ Innd{orms and thc procc�scs that shapc tlicm and is particulsrly
relcvanl lo sircam funceions within �hc conicxt of a watershed nsscssmcnt A goomo�phic analysis of
smcan� chenncLs in thc Agua I lcdionde wutcrshcd w �nductcd to c�aluotc how gwniorphic proccsscs
havc inilucnccd thc cxisting cM1anncls, and to i cstigatc thc � cd for and nppropriatcncss of strcum
cs[oraicion n �.. . Thc a�alysis uf thc gcuinorphic c ndiHon indudcd two prin�n�y c n�yoncnis:
1) obscrvations � iadc during a Fdd a- ... cnq and 2� a o£hismric data including a ial
photog��plry and lopo�raphic maVs� An w�lu�tiov ot simulaced Irydrology {��on� xhe waicr-shcd model
suppicn�cnmd tl�csc analyscs.
Rascd on ihc ftcld a .. cnt, thc c isGn•�, •. orphic c mdiGon oT sircam channds in ihc Agua
I3cdio idv aicrahcd sPans �lic lul] iangc ol pos�'blc conditiuns or stagcs of dia�nicl altcra�ion_ Soiiic
achcs do� ot cxhfbit instability (c.g., t6c upper rcadi o£ La Mirada Crcck and thc upper rcach o£littic
Encinas Crcck). O�hcr rcachcs mro tyV�c. 1 of incising and widcning r achcs, including thc upPo' rcach of
two hcxdwatcr trlbutarSas [o [3ucna Crcch, [hc ccntrul portioii o£Aoua Ilcdionde Crcck (shown Sn Fiyurc
4-2) and thc upper rwcl� of Calavcrn G'cck. Son�c rcachcs appcar co havc naturally rr�chcd a statc oi
post-disturbancc cqullbriiun (c.g., tlic upper rcach oPAvua [Icdionda Crcck).
0
Agua Hedionda Wate�shed Management P/an —Final August 2008
Thc rcvicw of historic da�a utilizcd a s- -s of his�orical av-risl photograPhs for thc Y���'s 1939. 19( 2,
1 390, and 2002. Thc availablc aeria] photogr plis rcyresenL coodiiions that rmec liom rclativcly spssrsc
dcvclopn�cnt to c- cnt Icvcls oFdcvclopnicnt. Thc l�istornc wntcxt providcd H�rough tM1c a- ial
photogiapli re�iew allows for prdimina�y nsswsn�enrs ofmoiphologic diange due to natw-al v2riability
v��5us m�pact> duc. to human inllucnc.a.
In cmijuncHon, thc ficld a cnt and a iel photoeraph a�alyscs r calcd ihat thc stabil Iry of thc
chnnncl has bccn ncgativcty�impnetcd ovcr timc at many locatio�is throughou� the st�cain sys�cni. The
o{ults aug�cs� Oiat channcl modfl9catiun duc �o past w2icrshcd devclopm nt M1as occunccl f ny parcs
thc watcrsM1cd_ Thcsc impacts a ost signi}{cant ovo- a rcnch ofupper Calavcra Crock�and�mud� ol
tfic lownr rc:ac9�es of A�c��a Iiedionda Creck (Fi�u c 4-3). O�her imPacled r ehcs were noicd bw � - ot
s��z„�n�a�,�_ f, ��„h��,�ro�, �r ��a��������o�,. ���s�o��ac�o�,, a�,a Sc���,,.Ha«� ��r�-�e� „��a�c���� �� ��d�d �o
eddress �hcsc � sting iinP��c1s. Plznncd ncw dcvclopmcnl has �hc potontial to lutthcr dcgradc�stieam
chunncls in tlic�Aeua I Icdfonda watcrshcd, altM1oueh thc impxcts c n bc mlGgetcd to a lar�c cxtcnt by
isiin�x BMP rcquircmcnts �ha� addmss pcak Flows fi-om fuwrc dcvclopmau. Thc nccd lorxddi�ional
protccGon n should bc cxplorcd durnng tlic dcvcLopmcnt of thc San �icgo Rcgion
HY��omodil3ca�ion�Plan; �his plan ic cun'cnity bcing dcvNopcd and will inGudc morc proiectivc mc.asuros-
❑ian storniwatcr controls that a�c. �uncntly in placc <sec Appendix A£or n�orc detalls).
Owrww�w�
Rgure 4-2. An Incised and Witlening (witFi r¢cent slumping) Reach oF Agua Hedlonda CreeK
Agua Hediontla Watershed Managemen2 P/an - Fina/ Auqust 2008
N 1 . F �, ��_�g�_�o.Y�-.`�'�.a.=
j� t J q �
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u
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-- iJG3Cliannel
- t990 CM1ann¢I
2002 CM1annal
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At.+rial Imagef 2002
Figure 4-3. Chann¢I Analysis in Lower Agua Hedionda CreeK
4.2.1 Comparison with Hydrologic Modeling Results
HY<hvmodiFcacion is a onccrn i� many Southcrn California watc�shcds. Hydromodiiicntion is thc
aLLer�Gon of thc nxtural Oow ol wa�cr through a Izv�dscapc. wid typicnity ixkcs LL�c Fonn of strcum chnnncl
nodilScntion or channcliiaiion_ Hy lrographs, plots illustratin" thc mvgnitudc oi _strcam (low during a
storm evem, w crestci based on simulation results fvm thc wa�crshed modeL Thcsc hydrographs
provldcd i� faht i��to tl�c po�cntfnl i�npact that changes in tl�c ratcs and volun�cs o{strca�nflow-ean havc
on sa-cain channGs. Pcak flows undcr cl>c FLwrc BMP Sccnariu wcrc �cduccd �o or bclow Existin� lavcls
mly c cry c 1-lowcvcr, a focus on ihe iafls of'thc stom� c rnh rcvcalcd persistcncc ovcr Gmc of
highcr flows in thc�Fuwrc [3MPs Sccnario. "I'hough its vffcct in Uic Agua Hcdionda watershcd is unGcur.
tliis i� n �hc duration of clwatc 1 Ilows hvs bccn u iatcd with a potcnfial for addfGonal svcam
chennd impa�cc _ Studlcs havc indicatcd tliat convolling oNy thc pcak Flow may not bc f Jly protcctive ol
straam chan�cls duc fo an incroasc in thc duratio�� ofcrosivc bank£uLl and sub-banlc£ul] c cncs fBrown and
Cmraco. 2001 )- Attcmpts to mitigatc thc proUlcm havc oRcn i orporatcd cxtcndcd dctcntion and slow
rc(c�sc of a channcl pro�ec�ion voLume. This imu� should bc czplored Curtlier durina tls developnicnt o£
thc Hydromodiiication Plan f r thc county.
To coinparc niodcling r sults with thc gcomorphic a�aiysis, a hydrologic n�ctriq T�,,,�,,,_ w s dcvcloped
for thc prcdcvcLopmcnt�nnd cxis�ing s - . e LL�c GcoTools pachvgc (RaC£ct ul., 200�). TM1c
subwatcrshcds witli tls Icas[ perccntagc�changc would bc xpcctcd to huvc tl�c Icast i npact on channcl
Omw�ro�
Agua Hedionda Watershed Management P/an - Final August 2008
orphology. Thc g ioryhic anatysis idcnGTicd thc UpperAgua il�i3onda Crccl. and n>st oPthc
anainstem oF [3ucnn Crcck as cxhibiting littic channG viovcmcnt ovcr timc. l�hcsc arcas con-cspond we❑
to thv subwatershads wS�li th� laast change i� T�,,,�,.,, Cf. , tlie light orangc and yellow shadcd areae in [hc
upper por[ion o£ the watcrshed shown in Figw-c 4-4). The imyacted r aches c n thc upper Calavera Creck
�oted in the g.emnoiphic anulysis concspond to subwalershcAs with la�gc changes in tl�c �no[ric (c.f.
subwntcrslicds 1011 and LO10 in Flgure 4-4). La Mnada C:realc is a r�ding (accun�ulating sedinient)
based on Hie si�c evalua�ion conns�oonding to a nwdcratc T�,,,,,;,,, diffc-cncc in thc uppo� drainagc arca_
Arcas whers ihc [wo Iines of widence, the �eorooxphic analysis and the model, do not converge arc 1t
Little Gacinas Creck �and Roman Creck. The cxpected geomuiphic impuct to 2oman Creck based on thc
diifcrcncc in To,,,,,,,, i- ot rcalizcd, apparcntly duc to thc prc of largc rock � ntributing to stabiliry.
FSeid characteriza�ion nu=ar the oullet of 2oman Creek showed�a�ch�nncl �ha� nissy huve becn i�npacted in
[hc i�ast but was cquilibrn�ting to waicrshcd conditions.
4.3 CLIMATE CONDITIONS AND TRENDS
Hydrologic conditions in thc r within Califomie, and in thc Colorado Rivcr basi�� will likcty bc
altcrcd as a resul� of global cli�natc�changc (bascd on conditions obscrvcd o�cr thc past cwnuiy).
According m a�cccni Cali£ornia Dcpartmcnt o£ Watcr Rcsourccs (DWR) rcporc
"C13matc chnn�c may s- isly af£cct thc Statc's watcr resourccs. Tcmperaturc i� _
could alTect water demand and aquatic ecosystems. Changes iu ihe �iming and amount of
Qmw�wu� 4-�
Figure 4-4. Changes in Hytlrologic M¢tric (TQ,,,Qa„) from Predevelopment fo Existing
Agua Hedionda Watershed Management Plan — Final August 2008
precipitation and runoff could occur. Sea level rise could adversely affect the
' Sacramento-San Joaquin River Delta and coastal areas of the State."
Potential effects of climate change on Califomia's water resources and expected consequences include:
• Reduction of the State's average annual snowpack
• Changes in the timing, intensity, location, amount, and variability of precipitation
• Long-term changes in watershed vegetation and increased incidence of wildfires
• Sea level rise
• Increased water temperatures
• Changes in urban and agricultural water demand (DWR, 2006)
These consequences could have a significant impact on the Agua Hedionda watershed. More intense
coastal storms could magnify the hydromodification effects in the channels causing additional erosion and
sedimentation. Rising sea level would inundate existing lagoou saltwater marshes. If preserved land is
present along the margius of the lagoon, raising sea level could represent a shift of habitat into these
margins; however, if additional land is not preserved, the rise may result in a permanent loss of salt marsh
habitat. The watershed beaches may also shrink because of rising seas and increased erosion from more
intense winter stoims. Currently, many beaches are protected from erosion through manmade sand
replenishment (or "nourishment") programs, which bring in sand from outside sources to replace the
diminishing supply of natural sand (CCCC, 2006).
4.4 HABITAT CONDITIONS AIVD TRENDS
� The Agua Hedionda watershed has experienced an extensive loss of habitat throughout its terrestrial,
wetland, and aquatic ecosystems. When vegetation cover was mapped in 1995, about 27 percent of the
watershed remained in natural, relatively undisturbed areas. This natural vegetation has decreased since
1995 to about 22 percent of the watershed, and without iurther habitat protection or restoration, natural
area ili the watershed is likely to decrease to 12 percent at build-out based on the extent of currently
protected natural vegetation in the watershed.i The following sections describe the general habitat
conditions in the watershed and provide information on lagoon habitat, plant communities, and sensitive
species. This infonnation provides the baseline for evaluating manageinent opportunities that can restore,
preserve, and enhance habitat for plant and animal species in the watershed.
4.4.1 General Habitat Conditions
This section provides an overview of generai habitat conditions in the watershed, and addresses four
major habitats: riparian, wetland, aquatic, and upland. Existing habitat connectivity within the watershed
is also discussed. All forms of habitat in the watershed not only provide wildlife habitat but also provide
watershed and water quality functions that contribute to the overall health of the Agua Hedionda
watershed.
A detailed, comprehensive inventory of vegetation cormnunities in the region was last conducted in 1995
by the San Diego Area Council of Governments (SANDAG). Figure 4-5 displays the distribution of
major vegetation classifications within the watershed (SANDAG, 1995). Although most of the watershed
I Local and regional governments are currently preparing habitat inanageinent plans that may protect
additional land once enacted.
a r�rRw�
4-8
Agua Hedionda Wate�shed Management P/an - Final August 2008
. class9ficd as non-native vegctatiov, unvegc[ated land, or devdoPed land, signiflcanl a�..ns ol
scruh/chaparral and hcrbaceous wnuncuuGcs aic pmscnt (Tablc 4-2)_
�e9end � -Iq
o. . �� —�
ee �s � .sss� ' �rJ �
..,....'.�..�.�.�s .,.�.�. ., ... -I i r
�` ,..,...,.., � m�Jr_k�i/
`� i
\ �
�
a __�� � .
� � �
�y
.. 4 �-�
/
s" --� � � i
....� - _ �-G12 ' -;_L
.. ' �,. � �{ - •1 -� �.'
_ � , ..
-`-.:;ncG,-, ,
:t--�' - -� : ay
t:Y' �_�tZ- �, ,L- � � . -..
v� � �_� '
�� t� ����� �
) : �
t'�F - )
� _ ,� .. .
~�-- '. .: -i . G � -r
\^—� �-`� ..,. �.� ��. � �.� % �
_. -.- � � . ..
., , „ �
.. �. . ,,,.,�:.. .,...., � ' " OrEr....rE�..
............ �
Figure 4-5. V¢getation Gommunities Available in the Watershed
Tabl¢ 4-2. Vegetation Community Types in Agua Hedionda Watershed
Vegefa[fon Communify Acreage
Non-native Vegeta[ion, �eveloped Areas, or Unvegetated Habitat t4,'100
Scrub antl CM1aparral 3,BD0
Grasslantls. Meatlows, and Other Herb Communities t,200
Riparian antl Bo[[omland Habi[at 500
ESW arina 300
Bog antl MarsM1 200
Dis[urbed We9antl 53
Wootllantl 26
Forest O.t
O
Agua Hedionda Watershed Management Plan — Final August 2008
Many of the natural vegetation communities are fragmented due to roads, agriculture, and residential and
commercial development. As natural vegetation communities are divided into smaller and smaller
parcels, native plant and animal species may be threatened due to reduced mobility. Meanwhile, invasive
species often thrive iu fragmented habitats (discussed in more detail in Section 4.4.1.2).
Riparian habitat (also known as riparian, or stream, buffer) exists between stream channels and upland
areas and provides important benefits for the protection and restoration of watershed functions. This land
provides habitat, protects streambanks from erosion, and acts as a filter for many pollutants from adjacent
upiands. By approximating the historic extent of riparian vegetation, Tetra Tech estimated that 60 percent
of riparian vegetation has been lost. Land along stream channels in Figure 4-5 with little or no natural
vegetation indicates areas where a major loss of riparian habitat has occurred. Loss of riparian habitat has
occurred throughout the watershed, but this loss is most evident along Buena and Agua Hedionda creeks
in the central and upper portions of the watershed and along the upper reaches of Calavera Creek.
Wetland habitat may overlap with riparian habitat and generally includes seasoually or intermittently
flooded areas that provide a transitional habitat area between open water and dry laiid. Wetland habitat in
general supports a high degree of biodiversity. Some wildlife species depend on wetlands as their
exclusive habitat, while others that live in upiand areas still depend on wetlands for essential resources,
including food and water. In addition to wildlife functions, wetland habitat provides functions important
to water quality, inciuding nutrient cycling and sediment trapping.
The loss of wetland habitat has been particularly significant within the watershed. California has lost
more than 90 percent of its historic wetlands and has experienced a much greater loss than the national
average of 50 percent (State Coastal Conservancy, 1989). Agua Hedionda watershed exemplifies this
loss. Using hydric soils data and the National Wetlands Inventory, Tetra Tech estimated that the
watershed has experienced an 82 perceut loss in wetland habitat. Historically, most of the wetlands likely
occurred in the lower, more coastal portion of the watershed. Much of this land is either highly developed
or disturbed by agriculture, leaving little coastai wetland habitat remaiuing except for the lagoon. Venlal
pools were likely to exist historically in the watershed, but neither Tetra Tech's research nor stakeholder
knowledge has indicated that any vernal pools remain. � The locations of existing wetlands can be seen in
Figure 4-5 within the bog and marsh and riparian and bottomlaud habitat vegetation classes. The
disturbed wetland class indicates locations of wetlands that may still exist, but vegetation has beeil
disturbed or removed.
Considering these wetland losses, the Agua Hedionda Lagoon is an iinportant habitat resource far the
watershed. The primary wildlife habitat provided by the lagoon is open water. In addition to the open
water areas, eelgrass beds provide habitat for fish and crabs, and mudflats provide feeding areas for
migrant birds. The marsh areas, although limited, provide additional habitat diversity for a variety of
species (State Coastal Conservancy, 1989). (See Section 4.4.1.1 for more details.)
Upstream of the lagoon, watershed impacts, including development, have degraded or destroyed aquatic
habitat withiu stream channeis. Biological inonitoring data indicates that benthic macroinvertebrate
biodiversity is relatively poor at select sample locations in the watershed, as reported in Tetra Tech
(2007). During October 2007 field reconnaissance, Tetra Tech evaluated aquatic habitat qualitatively
throughout the watershed and found a range of aquatic habitat quality, inciuding some potentially high
quality sites. Benthic inacroinvertebrate sampling at additional locations inay reveal higher diversity in
locations with higher quality habitat, but these results are difficult to project based on the intermittent
nature of the streams and the high sediment load throughout the watershed.
' A vernal pool is a shallow, intermittently flooded wetland that is typically dry during the stiiminer and fali (Mitch
and Gosselink, 2000).
Q ��r�u►�
4-10
Agua Hedionda Watershed Management Plan — Final August 2008
The diverse habitats within Agua Hedionda watershed support species sensitive to further habitat
degradation, including those listed on state and federal endangered and threatened species lists. Table 4-3
lists the endangered and threatened species, designated at the state and federal levels, that are likely to
occur within the watershed or have occurred in the past. At the federal level, a species is designated as
"endangered" if it is in danger of extinction within most or all of its range, and a species is designated
"threatened" if it is likely to become an endangered species in the future. The state listing generally
corresponds with this definition, but some species may not match the federal listing if they are considered
more or less rare within state boundaries.
All listed species except for two are presumed to occur in the watershed (noted as "presumed extant" in
the table). The tidewater goby (Eucyclogobius newberryi) no longer occurs in the Agua Hedionda
Lagoon and is thought to no longer occur in the watershed (noted as "possibly extirpated" in the table; see
table footnote). The California least tern (Sternula antillarum bYowni) has been observed in the vicinity
of the lagoon but is not believed to 11est within the watershed due to absence of foraging habitat (MEC,
1995) and is designated in the table as "extirpated" (see table footnote).
Table 4-3. Federal and State Endangered and Threatened Species Identified within the Agua
Hedionda Watershed (CNDDB, 2008)
� �� �
�
Fetleral
Scientific Name Common Name Presence' Listing State Listing ;
Presumed
Acanthomintha ilicifolia San Diego thorn-mint Extant Threatened Endangered
Arctostaphylos
glandulosa ssp. Presumed
crassifolia Del Mar manzanita Extant Endangered None
Presumed
Brodiaea filifolia thread-leaved brodiaea Extant Threatened Endangered
Charadrius Presumed
alexandrinus nivosus western snowy plover Extant Threatened None
Eryngium aristulatum San Diego button- Presumed
var. parishii celery Extant Endangered Endangered
Eucyclogobius Possibly
newberryi tidewater goby Extirpated2 Endangered None
Presumed
Navarretia fossalis Moran's navarretia Extant Threatened None
Passerculus Belding's savannah Presumed
sandwichensis beldingi sparrow Extant None Endangered
Polioptila californica coastal California Presumed
californica gnatcatcher Extant Threatened None
Rallus longirostris Presumed
levipes light-footed clapper rail Extant Endangered Endangered
Sternula antillarum
browni California least tern Extirpated Endangered Endangered
Presumed
Vireo bellii pusillus least Bell's vireo Extant Endangered Endangered
'��Presumed ExtanY' means that a species is likely to occur in the watershed; "Possibly Extirpated" means that a
species has been observed in the past but may not occur, at present, within the watershed; "Extirpated" means
that a species has been observed in the past but is unlikely to occur, at present, within the watershed.
2 The tidewater goby no longer occurs in the Agua Hedionda �agoon.
O r�rRw�
4-11
Agua Hedionda Watershed Managemen( P/an - Fina/ Auge�st 2008
Uuc to dic cxicns9vc loss oi'M1abirat a- all c osysicros, c isKng uyfz�nd habrtat is mportant ro c sido�
bccauso ii niaintains existing biodivcrsity�and proccccs watcr qualiry, particularly for�highly crodible�
uyla �d <- .]n tl�e lower portion ol Ihe watershed, mosl of ihc r ainin� upland � aturai v ctation hos
bccn prescrvcd, but fn thc uyper portioi� of U�c watcrshcd, largc tracts o1' upla��d habitxi[ rvmam
npruicctcd.
Anuthcr major habital imP��[ ha� bccn lhc losv ofconncctiviLY L c�w-ccn �hv upper and lowc. portiovs ol
chc watcrs6cd_ 9fncc thf.v- loss is duc to dcvclopn�cnt, ��o Fcasiblc oppurtun3ty c ists to res[orc []zfs habiiat
connectivity. Ocspitc Oiis loss. Gignificant tracLs of nawral wildli{ ��abitat still c ist both in Ihc lowcr and
upper yorGons oi thc watcrshccl, �nd � mbinxGon ol'prasarvaGon and restoraGon wuld bc succcssiui st
maintaining and rnhancing thc cwrcnt 1 abitat conncctivity.
4.4.7_7 Agua Hedionda Lagoon
Agua Hodionda mwns "stinking watcr" i i Spanish, namcd prc nabty bccausc oFthc odor o{thc
s � sw •
s�agnani water CMEC, 1995J. Agua Hedionda i� a salt n rsh slounL wliid� w s drad�ed to P�i c-znt
conFgwation i i 1954 hy San �icgo Gas 8c Glcctric (SDG�CJ to providc wolfng watcr for tls P_n�cina
Powcr Plani. Prior lo dredging, thc cswary was a slough that was onty occasionally opcn to lhe occan.
Thc lagoon c app�oximatcly 230 a- nd ie ade up o£throe bas3��s scparaicd by tl�c Railroad
(built in thc laic 1800s), ehc PaciFc Coast Highwey��localty r- mci as Ca�isbud Boulcvard (191 O), and
]ntcrsracc 5 C 1 96]). Tl�c thrcc lagoon basin� indudc thc 66-acrc ouicr basin (wcstcrninwt basin). thc 2]-
. niddlc basin, and thc I40-ac - -r basfn (AIILF, 1991). Thc lugoon is - cetcd to thc occsn by
nn�inlG bordcrcd by nvo rock jctticv�at �hc northcrn cnd of ihc nuto' basi l'hc Inc s OS i�ilc widc a�
oon �
Itc �a.5dcst polnt ancl cztends 1.� niilcs inlxnd 1}on� iM1c coast io thc nwuth oFA�uv I Icdfonda Crcck.
.. �c.___ . � . �
- ._ ._,_ - �z - _ --
- - ... - _"'__" �.c"_'. _ '•..:r�
__ --�..-_""____'_ -_ "
39%��Lql-.. .y�� . ... , .. _ — . _ -.�� �
' ..... . . �_��� �`- �-Ids
Y J . � .. . .., .M '_ " n� ' �' + ~
i a'��"�" q*+ ��.. �, it _ AL� ..� .
{ ���.Y"�; "��%����`�� �� �. ' 'e .
':+�. ; , ay. � . ^ i . .
S.�c `YF';'r, ` �. r�c.fil5d[.�ax.u," s.. i . � . � , . - . �i , . � . - -' - Pt'�ill"�iX
Figure 4-6. View of Agua Hedionda Lagoon
Qmwwru�
Agua Hedionda Watershed Management Plan — Final August 2008
- The original dredge depth of the lagoon was approximately 8 ft mean sea level; however, it is believed to
be shallower now due to sediment discharged from Agua Hedionda Creek and sand entering the lagoon
through the jetties. The outer basin is dredged every one to three years to remove sediment (mostly sand
entering from the ocean through the jetties) to maintain adequate water storage and related tidal prism for
drawing sea water for the once-through cooling system that cools the Cabrillo Power Plant on the
southwest edge of the lagoon. The inner basin was re-dredged once in 1998 through 1999. The inargins
of the lagoon vary significantly fi•oin gentle to steep slopes along the northern and southern shores, to
nearly flat salt marsh expanses along the eastern shoreline neat the mouth of Agua Hedionda Creek.
Eelgrass is found in all three lagoon basins primarily in the shallower depths which provide a
valuable habitat for benthic organisms that are fed upon by birds and fishes (MEC, 1995).
The lagoon empties into the Pacific Ocean within the Southern California Bight. Longshore currents,
driven by winds and ocean swells, generally move water and sand in a southerly direction along the coast.
The shoreline adjacent to the lagoon is gently sloping and sandy bottomed with occasional kelp beds. The
beaches outside of the lagoon are in the City of Carlsbad and are a popular destination for locals and
tourists alike for swimming, surfing, fishing, diving, jogging and relaxing. Beneficiai Uses of Agua
Hedionda Lagoon include:
• Industrial Service Supply (IND)
� Contact Water Recreation (REC-1)
• Non-contact Water Recreation (REG2)
• Commercial and Sport Fishing (COMM)
• Preservation of Biological Habitats of Special Significance (BIOL)
• Estuarine Habitat (EST)
• Wildlife Habitat (WILD)
• Rare, Threatened, or Endangered Species (RARE)
• Marine Habitat (MAR)
• Aquaculture (AQUA)
• Migration of Aquatic Organisms Spawning, Reproduction, and/or Early Development (SPWN)
• Shelifish Harvesting (SHELL)
The RWQCB has determined that the Aqua Hedionda Lagoon does not meet certain water quality
objectives for indicator bacteria and sedimentation/siltation (SDRWQCB, 2007). The RWQCB is in the
process of developing Total Maximum Daily Loads (TMDLs) for Agua Hedionda Creek aud Agua
Hedionda Lagoon.
The lagoon contains four primary habitat categories: subtidal, flats, marsh and upland. These habitats
support a large number and variety of species, soine of which are threatened or endangered. The lagoon
is an important habitat for coastal marine and resident fish, particulariy as nursery habitat for
cominercially and recreationally impoi-tant coastal species such as California halibut and diamond turbot.
The most abundant fish are silversides (topsmelt and juvenile atherinids) and gobies. Gobies consist of
five species, but the most common are arrow and yellow�n. The lagoon aiso supports a variety of benthic
invertebrates, including cockles, mussels, bubble snails, mud dwelling snails, amphipod crustaceans,
isopod crustaceans, mysids and shrimp. Following is a list of the special status bird species identified in
aud arouud the lagoon (MEC, 1995}:
Q r�w►�w
4-13
Agua Hedionda Watershed Management Plan - Final August 2008
- • California Brown Pelican - federally endangered
- • California Least Tern - federally endangered
• Western Snowy Plover - federally endangered
• Belding's Savannah Sparrow - State of California endangered
The majority of the lagoon is currently owned by Cabrillo Power II and supports a thriving marine
ecosystem. It is home to the Hubbs-SeaWorld fish hatchery and white sea bass research facility, the
Carlsbad Aquafarm (commercial mussel farm), YMCA Camp and the Agua Hedionda Lagoon
Foundation's Discovery Center. Surrounding the lagoon are agricultural fields to the south and
residential development to the north. The eastern shore of the lagoon is the California Department of Fish
& Game Agua Hedionda Lagoon Ecological Reserve. The lagoon extension of the reserve is designated
by the Califomia legislature, through the 1999 Marine Life Protection Act (MLPA), as a Marine Protected
Area (MI'A), known as the Agua Hedionda Lagoon State Marine Reserve. The piupose of designating a
MPA is to protect marine ecosystems, diminish the impacts from human activities that are altering and
degrading our coastal and marine environment, and improve recreational and education opportunities
offered by these special areas. There are three types of MLPAs: state marine reserve, state marine park,
and state marine conservation area, each with different rules about what activities can or camlot be done
within thein. In general, marine reserves do not allow any type oi extractive activities (including fishing
or kelp harvesting), with the exception of scientific collecting under a pennit, marine parks do not allow
any commercial extraction, and marine conservation areas do not aliow some combination of commercial
and/or recreational extraction.
Lagoon Restoration Efforts
�- � As a baseliiie for evaluating future management actions, recent lagoon restoration efforts will be
�, important to consider. Signi�cant impacts to the lagoon have been caused by excessive sediment loading
` and invasive aquatic plant infestation. Past restoration efforts have %cused on mitigating these iinpacts
and enhancing both the natural function aud industrial uses of the lagoon. The most recent restoration
efforts have been successful at restoring lagoon habitat and mitigating for sediment and invasive species
impacts.
Since the Cabrillo Power Plant uses the lagoon for cooling water and dredges the outer lagoon about
every two years, the Agua Hedionda Lagoon is one of the few lagoons in the area to receive continuous
tidal flushing because it is regularly dredged and has jetties (State Coastal Conservancy, 1989). Tidal
flushing helps to inaintain low concentrations of pollutants within the lagoon and reduce eutrophication
(Howes et al., 1991). The entire lagoon was completely dredged during 1998 through 1999, which
significantly increased tidal flushing. Following the dredging, eelgrass beds were restored to provide
enhanced marine nursery areas (San Diego Wetlands, 2008).
The most recent restoration project successfully removed an infestation of Caulerpa tcrxifolia, an invasive
seaweed. This invasive species was discovered in the lagoon in June 2000. Treatment occurred between
June 2000 and Septeinber 2001, and following treatment, surveys were conducted four times per year.
The last patch of Caulerpa taxifolia was eradicated in September 2002. Surveys were conducted twice
per year from summer 2003 through December 2005, and no additional patches were discovered
(SCCAT, 2008). The removal of this invasive species has protected and enhanced the eel grass beds
within the lagoon, which are an important habitat for fish and other aquatic species. If left uncontrolled,
Cauletpa taxifolia could be a lnajor threat to California inarine and tidal ecosystems. In the
Mediterranean Sea, where similar climatic conditions exist, the seaweed covers 30,000 acres of sea floor
and has destroyed uatural aquatic communities, displaced native piants and animals, and decreased
overall biodiversity. The Mediten•anean infestation has also caused economic damage to fishing, tourism,
boating, and other recreational industries (SCCAT, 2008). Protection from further infestations will be an
`- iinporCant inanagement activity for the lagoon.
O r�re,►rraa
4-14
Agua Hedionda Watershed Management Plan — Final August 2008
Sediment loading to the lagoon has caused impacts to lagoon habitat in the past, but dredging the inner
' lagoon on a regular basis could be cost prohibitive. Considering the success of recent restoration efforts,
the most promising restoration opportunity for lagoon habitat is likely to be the control of upstream
sediment loading which will involve stormwater BMP retrofits and stream restoration measures. If a
dredging project occurs in the future, upstream sediment management will help protect the benefits of that
dredging project as well. Land acquisition and buffer restoration adjacent to and near the lagoon would
enhance the diversity and health of the lagoon habitat and the wildlife communities supported by the
lagoon.
4.4.1.2 Invasive Plant Species
�f
�t.
Invasive plant species, both aquatic and terrest�ial, threaten habitat quality throughout the Agua Hedionda
watershed. Populations of invasive plant species can doininate a plant community by out-competing
native species, increasing soil erosion, and altering fire regimes, nutrient cyciing, and hydrology.
Invasive species data were coliected by the San Elijo Lagoon Conservancy (SELC) as part of their recent
study of restoration of riparian/wetlands habitat in the Carlsbad Hydrologic Unit (SELC, 2007). The sites
were identified through GIS and through local knowledge of infestations. Some invasive species
occurrences in the watershed may not be included in this dataset.
SELC found painpas grass (Cortaderia selloana) and giant reed (Arundo donax) to be the inost dominant
invasive species within the Agua Hedionda watershed (Table 4-4; Figure 4-7). However, the presence of
periwinkle (Vinca major), salt cedar (Tamarix sp.), castor bean (Ricinus communis), artichoke thistle
(Cynara cardunculus), pahns (Washingtonia robusta or Phoenix cana��iensis), and pepperweed (Lepidium
latifoliuin) are also a concern.
Table 4-4. Acreage of Invasive Plant Species Present in the Agua Hedionda Watershed (SELC)
Common Name Scientific Name Acreage
Pampas grass Cortaderia se//oana 98.4
Giant reed Arundo donax 22.9
Periwinkle Vinca major 6.9
Salt cedar Tamarix sp. 4.4
Castor bean Ricinus communi 4.3
Artichoke thistle Cynara cardunculus 3.6
Palms Washingtonia robusta or 2 �
Phoenix canariensis
Pepperweed Lepidium latifolium 0.01
Total 143.2
,��
4-15
Agua Hedionda Watershed Managemen! P/an — Fina/ Augeist 2008
�egena
oM.��„�.�..eo.,..�a..
rl
__-_._L__��
u� -. .
�_..� �
s��,s�'" n_ \
�J ! _
���
1/ ��_ `j'- _
'fi� . ,� :.�..._. . .
_ �- r�
...._....,. � Tw.rE��
Figure 4-7. Invaslve Plant Species Present in the Watershed
4.5 CULTURAL RESOURCES
Nativc Amcricans hnvc inhabitcd thc Agua Acdionda wato�.sM1cd for approximatcly 9,000 ycars and many
archcological si�c.v havc bccn Ai�covcrcd in thc watcrshcd (Howcs et nl., 1991 ). Thc Ius� Icnown
inhabitxncs w c the hunt�r-_eithcrer groups known mday .as tlic Kumcyaay pcoplc. Around 1,000 13.G,
�hc Luisrno pcoplc bcga i to inhabit thc �vatcrshcd, cithcr inplacing or co-cxisting with Ihc Kumcyaay
pcopic. Thc Luiscno pcoplc madc svl� and nathcrcd shclliSsh Ior Tood, tools, and jcwclry. Tha natfvc
pcoP�c Iivcd offthc abundant s a litc and fcrtilc lnnd along thc c ast of noithcrn Smn Dicgo County for
many ccnturics. Thc Luiscuo culluro changcd i2pidly with thc an-ival th¢ Spavish cxpedition of Don
Gaspnr dc Portola and Fa�hcr Juan Crespy and thc Mission San Luis Rcy w.is cstaUlishcd in I']9R (1-lowcs
cl aL, 1991; AHLP, 200R)_
'I'hc - any Luiseno P�ople living ioday who 2re active in tha Agu � Heciionda watershed prc -
thdr history, cul[ural and way oF liTc Thcsc local dcsccndants arc known as i-nibcrs of thc San�Luis �
Rcy Bnnd of MiGsion Indians Nativc Amcrican artifacts 2rc commonty uncart6cd during constivc�ion
projccts and promciion ofthcsc cultural r a l.cy considcrnGon during dcvclopmcnt o£tl�c Agua
Hedionda Watcrshcd (liowcs ct al__ 1991� AHLF, 200R)_
4.6 PRIORITY WATERSHED ISSUES
A nun�bcr c�f priority watcrshcd i - cgcd fom thc asscssn�cni ot watc�shcd condiiions and trcnds
s un
wfthfn ti�c A�ua 1 Icdionda water�hed. Urban land u c has i� ��sed over iimc in tlic watcrslied, rcplacing
a€�"�culWrc and nnwral opcn sF>acc ALLhough much ofnc� waioshcd is alrcady dcvclopcd. luwrc
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Agua Hedionda Watershed Management Plan — Final August 2008
development is expected to cause additional impacts to water quality and stream stability. Development
regulations are estimated to reduce future impacts if fully enforced. However, additional management is
needed to successfully improve and restore watershed functions. The watershed could be at greater risk
of degradation if planned redevelopment does not occur as represented in model scenarios (e.g., without
treatment as required by the 2007 Order).
Sediinent and bacteria were found to be particular poliutants of concern. Sediment nonpoint sources
include natural background sources, channel erosion, and stormwater runoff from construction, post-
constructiou, and agricultural sites. Bacteria nonpoint sources include natural background sources,
irrigation runoff, septic systems, sanitary sewers, transient encampments, and pet waste. Sediment and
bacteria concentrations in Agua Hedionda Creek appear to be increasing and may indicate increased
threats to water quality and aquatic communities under future conditions. Irrigation practices are believed
to alter natural hydrology and increase nutrient and bacteria loading during extended dry periods.
Waterbody impairments, as listed in Section 4.1.1, indicate portions of the watershed where particular
pollutants have degraded watershed functions. Impaired waterbodies include Agua Hedionda Creek,
Buena Creek, and Agua Hedionda Lagoon.
Stream channel modification, from a natural to impacted state, has been observed throughout the
watershed. Typical impacts include habitat degradation and channel and bank erosion. These impacts are
most significant along the upper reaches of Calavera Creek and much of the lower reaches of Agua
Hedionda Creek. Although current regulatory efforts are expected to reduce impacts from future
development, future development is expected to have some effect. If current impacts are not addressed,
future development could lead to greater channel instability and increased erosion. Control of peak flow
inay not be sufficient to protect stream stability and channel protection volume requirements may be
warranted. Current impacts will need to be addressed as well, especially reaches identified as highly
�
unstable.
`..;; The watershed has experienced significant loss of natural habitat across all ecosystems. The majority of
wetland and riparian habitat in the watershed has either been cleared or developed, and these losses are
most evident in coastal areas, upper Calavera Creek, and along Buena and Agua Hedionda creeks in the
central and upper watershed. The largest areas of unprotected habitat, both riparian and upland, exist in
the upper watershed, while the largest protected areas occur in the lower watershed. Currelit habitat
planning efforts may protect additional land, but without additional preservation efforts, future
development could reduce natural habitat to 13 perceut of the watershed.
Predicted climate chauge may present a challenge to plamling long-term management in the Agua
Hedionda watershed. Extreme shifts in weather patten�s may increase sediment loading, channel erosion,
and other stressors that already have an impact on watershed functions. Climate change may also
endanger existing habitat and could present increased hazards to both human and aniinal life in the
watershed.
Due to the large number of priority issues within the watershed, successful inanagemellt will require
attention to how different pollutant sources and stressors interact in the watershed and how different
management techniques can be brought together to address these multipie issues. A review of current
regulations and policies can help to further difFerentiate pi-iarities by uidicating where policies will
address priority issues and where additional management is needed.
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Agua Hedionda Watershed Management Plan - Final August 2008
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Agua Hedionda Watershed Management Plan — Final August 2008
..�' ' i � 1 i i . � .�
Section 4 considered existing and future conditions within the watershed and identified the priority issues
for management. Toward addressing these issues, an evaluation of current regulations was used to
detennine if additional policies or regulations would contribute to the goals of this WMP. Appendix A
summarizes the current regulations and policies that are relevant to the WMP goals, including water
quality standards, stormwater management requirements, riparian buffer requirements, floodplain
management requirements, and habitat management plans.
Management building blocks are regulations or policies that are currently addressing a priority watershed
issue and whose benefits can be augmented by additional management. Management gaps occur where a
policy does not address a particular priority issue or objective in the watershed. Identifying building
blocks and gaps in management can lead to the selection of priority management needs, like habitat
restoration, within the watershed. In this section, key management building blocks are discussed and
management needs are identified.
5.1 KEY WATERSHED MANAGEMEIVT BUILDING BLOCKS
The review of current regulations and other policies within the Agua Hedionda watershed revealed a
number of manageinent building blocks for the WMP. Efforts to improve watershed functions within the
watershed have been ongoing for at least two decades. Local governments began managing stonnwater in
the 1990s, and stormwater management requirements for private development began with the 2001 Order.
More recent efforts, like the 2007 Order and the ongoing habitat management planning, continue to
reduce impacts to watershed functions. The Agua Hedionda WMP considers the current management
framework and how implementation of the plan can work alongside these efforts to achieve the plan's
goais and objectives. This section highlights current watershed management efforts that can be
augmented by the WMP and management gaps not currently addressed by existing policies.
303(d) List and TMD�s
Section 4.l lists the impaired waters within the watershed. Waterbodies are placed on the Califonzia
303(d) list if the water quality objectives are not met, indicating that the existing and potential beneficial
uses of these waterbodies are impaired. The RWQCB will be developing Total Maximuin Daily Loads
(TMDLs) for these impairments. The water quality assessinent in Section 4.1 indicated that sediment and
bacteria loading are particular pollutants of concern for the watershed. The listing of Agua Hedionda
Lagoon for sedimentation/siltation aud bacteria will help support management efforts to reduce these
pollutants in the future. The listing of Buena Creek for nitrate, nitrite, and phosphorus will also help
support management efforts to reduce nutrient loading to Buena Creek, an issue highlighted in the water
quality assessment. However, completion of these TMDLs, except for the lagoon, is not expected until
2019, and implementation of management as a result of each TMDL is uncertain. Except for the lagoon
impairment, it does not appear that other impairments in the watershed will be addressed within the next
10 years. Although the lagoon TMDL inonitoring is moving forward, completion of the TMDL
Implementation Plan is not anticipated for a few years.
�
The Integrated Regionai Water Management Plan (IRWMP) is a regional water resource management
effort that represents concurrent efforts aimed at securing long-term water supply reliability by first
recognizing the inter-connectivity of water supplies and the environment and then pursuing projects
yieiding multiple benefits for water supplies, water quality, and natural resources. Although the schedule
plan updates vaiy, the project lists are usually updated every few years, and the plan is likely to be
updated every five years (Rob Hutsel, San Diego River Park Foundation, personal communication to
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5-1
Agua Hedionda Watershed Management Plan — Final August 2008
,- Heather Fisher, June 2008). Opportunities identified through IRWMP planning efforts that remain
unfunded could be investigated for implementation by local jurisdictions and organizations. Likewise,
opportunities identified through this WNIP could be implemented that augment effarts under the IRWMP.
Agua Hedionda watershed management efforts should include tracking where IRWMP implementation
occurs in the watershed. Public review periods for future IRWMPs can be used to support a greater focus
within the Agua Hedionda watershed if past IRWMPs have overlooked important opportunities that relate
to regional water resource priorities.
RWQCB 2007 Order
The 2007 Order is a major management building block for this WMP. The requirements of the 2007
Order that particularly relate to the WMP's goals and objectives are: 1) Low Impact Development, 2)
Hydromodification Plans, 3) Sediment and Erosion Control and 4) Watershed Urban Runoff
Management. The degree of successful implementation and enforcement of these requirements will
determiue their effectiveness on improving watershed functions within the Agua Hedionda watershed.
Stormwater best management practices are currently selected based on a qualitative assessment of
pollutant removal efficiency (high, medium, or low removai efficiency; see Appendix A for more details).
Without quantitative pollution reduction targets (e.g., 87 percent removal rather than "high efficiency"), it
will be difficult for jurisdictions to ensure that stormwater manageinent is fully addressing pollutants of
concern and protecting water quality from further impairment. Quantitative reduction targets or
requirements would need to be implemented in a way that is both consistent from development project to
project, and relatively easy to implement and enforce. Simple, cost-effective modeling tools (i.e.,
spreadsheet-based tools) could be utilized that predict development site pollutant loading, helping
jurisdictions enforce stonnwater regulations. The modeling tools would measure the pollutant removal
efficiency of storinwater BMPs and predict the pollutant loading rate for a development site, based on
� local or regional data. Developers could enter their site data into the model to test performauce and make
��_ necessary changes to the site, and development review staff could compare model output to loading
targets and determine if a development meets the stormwater requirements.
The 2007 Order Low Impact Development requirements for priority developments have the potential to
provide a substantial reduction in impervious surface aud promotion of infiltration within the watershed.
However, locai enforcement will detennine how effectively these requirements are implemented.
Development plan review staff will need to be knowledgeable of LID techniques alld be able to identify
where LID impiementation is lacking in development plans. The extent to which specific LID BMPs are
required wili also affect the effectiveness of the 2007 Order. For example, the BMP "minimize
disturbance to natural drainages" would ideally be interpreted as using natural drainage paths within the
site's stonnwater inanagement system. If this requireinent is not strictly enforced, it could be interpreted
inore broadly to mean minimizing direct impacts to stream chaimels without attention to drainage paths
throughout a development site. The effectiveness of the 2007 Order wiil depend on each jurisdiction's
interpretation of the requirements. Guidance provided as part of this WMP can provide insight into more
speci�c and ei%ctive requirements for the use of LID in the watershed. Since local jurisdictions will be
working on their specific interpretation within the next two years, this WMP can provide timely support
and guidance to those jurisdictions.
The permanent hydromodification requirements, projected to be in place by 2009, will help protect
streams from increased channel erosion and instability. Tllese requirements will address impacts from
future new development and redevelopment. Although these requirements will help minimize future
impacts, development approved prior to 2009 will not be obligated to comply with these requirements.
This gap in management could lead to increased impacts in the short-term. Current and future regulations
will be addressing peak flows, but it is possible that channel protection volume requirements will be
needed to protect streams from further degradation. Since a large portion of the watershed is already
developed, additional management in already developed areas will be needed to thoroughly address
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Agua Hedionda Watershed Management Plan — Final August 2008
current levels of bank erosion and instabiliry, especially in areas that are not likely to redevelop. Stream
channels impacted by past developinent will require measures to restore natural channei morphology and
bank stability.
Although regional sediment and erosion control (S&E) requirements have not changed significantly
between the 2001 and 2007 Orders, the local jurisdictions could take advantage of this ordinance change
to strengthen S&E enforcement. Tetra Tech was unabie to determine the extent that sediment loading
from new construction was contributing to sediment within streams. However, upland sediment loading
is expected to have an impact. If jurisdictions review how effective their current requirements are and
assess compliance, they may determine that stricter requirements or enforcement would lead to sediment
reduction benefits.
The 2007 Order also requires that the jurisdictions within the Carlsbad Watershed collaborate in the
developinent and implementation of a watershed-based program that addresses urban runoff quality. They
are required to identify high priority pollutants and their sources and develop collective watershed
strategy to abate the sources and reduce the discharge of pollutants causing the high priority water quality
problems of the watershed (it should be noted that for the 2007 Order the watershed is defined at the
Carlsbad Hydrologic Unit and the Agua Hedionda Watershed Is a sub-watershed). The Carlsbad
WIJRMP Co-Permittees are also required to measure the effectiveness of their program which can be
leveraged with the monitoring recommendations of this WMP. The WLJRMP requirement of the 2007
Order is a strong building block for the WMP.
Riparian Buffer Protection
The cities of Carlsbad and Vista and the County of San Diego have buffer regulations in place that will
provide soine riparian habitat protection for future new developinent and redevelopment. Increased
riparian area protection would provide additional habitat and water quality benefits. All jurisdictions in
� the watershed address riparian buffer protection to some degree in their stormwater management
�
` regulations, but additional protection measures could be warranted. As discussed in Section 4.4, the
maj ority of riparian habitat has already been impacted. Restoration of riparian habitat would be needed to
fully address habitat and water quality needs within the watershed.
Floodplain Management
Local floodplain management ordinances currently provide prevention of flood hazards and some degree
of flood retention by prohibiting most structures within the floodplain. Past development has likely
impacted much of the watershed's natural flood retention and control functions. Both the regulatory
review and habitat assessment results suggest a need for natural floodplain restoration within the
watershed.
Habitat Management
Cun•ent habitat management plauning efforts, both regional and local, provide a coinprehensive and
effective means for protecting critical habitat for sensitive species. The MHCP subregional Plan and the
Carlsbad Habitat Management Plan (HMP) are protecting critical habitat in the lower portion of the
watershed. MHCP sub area plans for Vista, San Marcos, and Oceauside are expected to protect additionai
critical habitat once finalized, and the North County MSCP is expected to protect critical habitat in the
remainder of the watershed. Across the watershed, these planning efforts will provide an important
building block for watershed management. However, these efforts focus on habitat and not speci�cally
on protecting land for multiple purposes, like downstream water quality and channel protection.
Additional habitat management will likely be needed that addresses all priority issues within the Agua
Hedionda watershed while building upon current habitat protection efforts. Habitat management should
include both preserving additioual natural areas and stewardship of preserved areas. Once the HMPs are
finalized, WMP impiemeiltation should focus on protecting and managing habitat and sensitive species
that are not addressed by these HMPs.
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Agua Hedionda Watershed Management Plan — Final August 2008
�~ �r� Water Conservation
4
--- In 7une 2008, Governor Arnold Schwarzenegger formaliy declared that drought conditions exist in
California and called for a number of steps to address drought conditions throughout the state. The
declaration calls for increased water conservation by local governments and water agencies as part of a
suite of proposed ineasures (Steinhauer, 2008). As a result of increased water conservation, water use for
irrigation may decrease in the future.
Appendix A includes a summary of the State of California's model water conservation ordinance, which
is currently under development. This ordinance, once in place, is expected to fill an important
management gap within the watershed. The watershed assessment revealed that nutrient loading during
extended dry periods i11 Buena Creek is likely caused, in part, by irrigation of lawns and landscaping.
Improved water conservation will help address this loading and return stream hydrology to a more natural
cycle. Impiementation of the model water conservation requirements will likely require stakeholder
support and outreach to fully achieve the benefits of the stricter requirements.
Ongoing Infrastructure Improvements
Local jurisdictions have recently developed sewer master plans and storm drain master plans, and these
plans are resulting in ongoing alid upcoming infrastructure improvements. Since sewer pipes are often in
the creek, sewer pipe removal, relocation, or replacement may coincide with preservation or restoration
opportunities and could augment these management efforts. Jurisdictions will also be required to mitigate
impacts from infrastiucture projects which may provide further opportunities for preservation and
restoration within the watershed.
Current Non-Regulatory Management Efforts
Non-governmental organizations have been working in the watershed to manage and improve watershed
� functions. One example of these efforts is the removal of the invasive aquatic plant Caulerpa from Agua
Hedionda Lagoon, which was a joint effort between the Agua Hedionda Lagoon Foundation and Southern
California Caulerpa Action Team, described in Section 4.4.11. The major NGOs working in the
watershed are:
• Agua Hedionda Lagoon Foundatioli
• Preserve Calavera
• Friends of Hedionda Creek
• Carlsbad Watershed Network
Management efforts within the watershed are not limited to the scope of the above groups. San Elijo
Lagoon Conservancy (SELC) has also been active in the watershed through monitoring and invasive
species management efforts. The San Diego Coastkeeper is an organization that trains stream monitors,
collects monitoring data, and participates in watershed management efforts, and Surfrider is involved with
key watershed issues in the region. Additional groups are expected to be interested in continuing and
building upon their past inanagement efforts in the watershed.
Although many groups are active in the watershed, the watershed does not have an overarching
organization that coordinates ali watershed management efforts. A watershed-wide coordinating
organization, either through a local goveniinent or NGO, will be needed to successfuliy implement this
plau.
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Agua Hedionda Watershed Management Plan — Final August 2008
; 5.2 BASELINE CONDITIONS: GAP ASSESSMENT
Baseline conditions are those conditions within a watershed that are occurring or will occur in the future
without further efforts to improve watershed functions. The baseline conditions assessment evaluates the
existing and future conditions in the watershed without fiu-ther action in relation to the WPG goals and
objectives. The relationship among priority watershed issues, manageinent building blocks, and
manageinent gaps is considered as well. Through this assessment, types of management are identified
that will be necessary to achieve the WPG goals and objectives.
Goal 1. Design land use so as to minimize impacts on the watershed.
a. Design and construct infrastructure projects (e.g., sewer lines) in a manner that ininimizes
impacts on watershed functions (i.e., water quality, habitat, and hydrology).
b. Design and construct new developments, recreation areas, etc., in a manner that ininimizes
impacts on watershed functions, including ininimizing impervious areas.
The baseline existing and future conditions relating to this goal and associated objectives center around
existing and future laud use/land cover in the watershed. The land use assessment under Section 2.3
shows that a majority of the watershed is currently developed, and that medium to high density land' wili
increase from 44 percent of the watershed in 2007 to 58 percent of the watershed in 2030. Increases will
occur across all medium to high density land uses, both commercial and residential, but the greatest
increase is projected in medium density residential, which is likely to increase from 5 to 12 percent of the
watershed. Since most of this increased density will occur in the upper watershed, the impact there wiil
be more significant. The average imperviousness of the watershed was estimated to be greater than 30
percent and is projected to increase with increases in development.
�` Past development and iucreases in impervious surface have contributed to the high poilutaut
concentrations and water quality impairments noted in the water quality assessment (Section 4.11). Iil
addition to these impacts, the geoinorphic analysis found that past developinent and infrastructure has
likely contributed to channel instability at many locations throughout the stream system. These impacts
appear to be caused, in part, by unnaturally high flows during storm events. Increases in developed land,
particularly imperviousuess, are expected to further negative impacts to streams.
The modeling assessment, described in Section 4.1, found that recently enacted regulations, particularly
the 2007 Order, will help to mitigate iinpacts froln future development. However, the model results were
sensitive to the following changes:
• Preservation of open space
• The conversion of agricultural land to residential and non-residential development that is treated
by stormwater BMPs
• The redevelopment with associated stormwater BMP treatment of significant portions of the
watershed
In particular, if the planned redevelopment does not occur as represented in the model scenarios (e.g.,
without treatment as required by the 2007 Order), the watershed could be at greater risk of degradation.
Further, since the assimilative capacity of the lagoon has not been determined to date, additional
reductions beyond those predicted by the watershed model in the future scenario couid be needed.
t Medium to high density land use includes all developed land uses except for parks/recreation, low density
residential, and very low density residential.
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Agua Hedionda Watershed Management Plan — Final August 2008
The majority of riparian habitat in the watershed has either been cleared or developed. This loss of
vegetated areas along streams has likely contributed to bank erosion and channel instability. Lack of
riparian buffers has also contributed to increased sediment and other pollutant loading to streams. Most
flooding occurs in riparian areas, and therefare flooding hazards are most likely to occur in areas where
riparian habitat has been cleared and developed. Riparian habitat within 50 feet of streams will be
protected in most portions of the watershed within the cities of Carlsbad and Vista and the County of San
Diego in the future. Disturbance of additional riparian vegetation, outside of the currently protected 50
foot buffers, may cause additional watershed impacts, and the past iinpacts to riparian habitat will
continue to contribute to watershed impacts if this habitat is not restored.
These results suggest that without further action, new development and infrastructure projects are likely
to cause increased watershed degradation. To assist in achieving Goal #1 and the associated objectives,
the Agua Hedionda WMP provides the following:
• Recommendations for ininimizing impacts from new development/redevelopment (Section 6.1)
• Identi�cation of high quality areas for preservation that could be severely impacted by
development (Section 6.2)
In concert with these strategies, infrastructure design to minimize watershed impacts should be
encouraged through policies and oversight by watershed jurisdictions and other stakeholders.
Goal 2. Protect, restore and enhance habitat in the watershed.
a) Protect and expand undeveloped natural areas to protect habitat
b) Protect, enhance, and restore terrestrial habitat, especially existing vegetation in riparian areas
c) Provide riparian habitat to improve and maintain wildlife habitat
d) Provide natural area colmectivity to improve and maintain wildlife habitat
e) Maintain stabie streambanks and riparian areas to protect instream aquatic habitat and mature
trees
fl Maintain and protect instream habitat to support native aquatic biology
g) Maintain and protect lagoon habitat
The baseline existing and future conditioils relating to this goal and associated objectives include the
existing and expected future conditions of the major habitat types iu the watershed: upland, riparian,
lagoon, and other wetland habitats. As established in previous sections, the watershed has experienced
extensive loss of habitat across all habitat types. Additional habitat, especially in the upper portion of the
watershed remains unprotected and threatened by future development. Mature trees along streambanks
are threatened by undercutting; some mature riparian trees have already been lost, and additional losses
are likely to occur if current hydroinodification and channel stability trends continue.
Recent lagoon restoration efforts have helped improve wetland habitat conditions, but excessive sediment
loading to the lagoon is likely to continue if upstream sediment sources are not addressed. Historic loss
of coastal habitat will also not be addressed without additional management.
To address these issues and help to achieve Goal #2 and the associated objectives, the Agua Hedionda
WMP identifies the followillg opportuilities:
• Land acquisition opportunities for habitat preservation
• Riparian buffer restoration opportunities
• Wetlands restoration opportunities
• Streain restoration opportunities
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Agua Hedionda Watershed Management Plan — Final August 2008
The indicators identified under Goal #2 were used to evaluate and prioritize these opportunities. This
identification and prioritization are described in more detail in Sections 6.2 and 6.3.
Goal 3. Restore watershed functions, including hydrology, water quality, and habitat,
using a balanced approach that minimizes negative impacts.
a) Restore and protect beneficial watershed functions and uses including:
■ Wildlife habitat
■ Recreation
■ Protection from flood damage
b) Design and construct restoration projects to minimize impacts to:
■ Streambanks
■ Riparian areas
■ Wildlife habitat areas
Since this goal encompasses all watershed functions, the baseline existing and future conditions relating
to this goal would include all priority issues discussed in Section 4.5:
• Sediment aiid bacteria were found to be particular pollutants of concern
• Impaired waterbodies include Agua Hedionda Creek, Buena Creek, aud Agua Hedionda Lagoon
• Stream channel modification, from a natural to iinpacted state, has been observed throughout the
watershed
� • The watershed has experienced significant loss of natural habitat across all ecosystems
• Climate change presents a challenge to planning long-term management in the Agua Hedionda
watershed
To achieve Goal #3 and its associated objectives, successful management will require attention to how
different pollutant sources and stressors interact in the watershed and how different management
techniques can be brought together to address these multiple issues. Iu addition to the management
techniques identified for Goals #1 and #2, the stonnwater best management practice (BMP) retrofits will
provide opportunities to reduce poliutant loading and control stormwater flows from past development
that otherwise lacics stormwater management.
To minimize potentially negative iinpacts froin inanagement opporiunities, the potential for one type of
manageinent to benefit or hinder another type of management will need to be considered. The plan
provides recorrunended focus areas iu which the complementary benefits of different manageinent
opportunities are considered. The focus area assessment identifies portions of the watershed where
inanagement is likely to successfully address the multiple priories under this goal, including recreational
areas, flood control, water quality, aud habitat. The focus areas are described in Section 6.8.
Goal 4. Support compliance with regional, state, and federal regulatory requirements.
a) The RWQCB has listed Aqua Hedionda Creek, Buena Creek, and Agua Hedionda Lagoon as
impaired and not supporting designated beneficial uses under the Clean Water Act Section
303(d). Future compliance includes:
■ Meeting water quality standards for Total Dissolved Solids, manganese, selenium, and
sulfates for Aqua Hedionda Creek
■ Meeting water quality standards for DDT, nitrate-nitrite, and phosphate far Buena Creek
(� ro,�,►�
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Hedionda Watershed Management Plan — Final
■ Meeting water quality standards for sediment and bacteria in the Lagoon
August 2008
b) The RWQCBand local governments in the watershed have stormwater manageinent requireinents
for controlling sedimentation and erosion during construction.
■ Track compliance with BMP requirements
�
�
c) The RWQCB and local govenunents in the watershed have LID and stonnwater management
requirements to control post-construction runoff from new development. Compliance will require
plan review, site inspection, and long-term BMP inspection and maintenance to ensure BMP
requirements are being met.
d) Reduce non-compliance events for water quality objectives and sedimentation and erosion control
The following management gaps illustrate the baseline conditions relating to this goal and associated
objectives:
• Planned efforts to address water quality impairinents within the next decade except for the lagoon
impairment, which is currently being addressed through the developinent of a TMDL
• Hydromodification requirements in association with the required Hydromodification Plaus
(HMPs) are under development but are net yet in place
• Numeric pollution reduction targets for stormwater management
• Specific requirements and implementation/enforcement methods for 2007 Order LID
requirements
• Methods to reduce upiand sediment loading from construction sites beyond current regulations
and enforcement
The first management gap indicates that although the lagoon TMDL is currently being developed, water
quality standards for impaired streams within the watershed are not likely to be met within the next
decade without additional watershed management. All management techniques recommended by this
plan would contribute toward meeting water quality standards, and plan implementation may prevent
other waterbodies from being listed as impaired. The selection of focus areas iu Section 6.8 considers
how inanagement techniques can be implemented to address impairments within the watershed.
The remaining three manageinent gaps indicate that local jurisdictions are working toward meeting the
2007 Order and may need support, through this watershed plan, to fully comply with the intent of the
regulations. This plan provides recommendations for effectively applying LID approaches within the
watershed (Section 6.1) and for conducting citizen education and outreach to help encourage compliance
with regulations (Section 6.6).
Goal 5. Increase awareness and stewardship within the watershed, including
encouraging policymakers to develop policies that support a healthy watershed. This
includes minimizing impervious area and providing for stream buffers.
a) Form collaborative Agua Hedionda Watershed Couucil to sustain long-term watershed
management.
b) Support adoption and implementation of the Watershed Management Plan as well as ordinances,
regulations, policies, and procedures by local jurisdictions, agellcies, and environmental
conservation orgamzations.
c) Disseminate information to local governments to support scientifically based, sound decision-
making.
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Agua Hedionda Watershed Management Plan — Final August 2008
d) Develop a consistent and comprehensive message for watershed health and actions citizens can
take. Distribute through website, water bills, press releases, brochures, and presentations.
e) Encourage Low Impact Development (LID) at the new development, redevelopment and
individual homeowner and project level.
fl Reward good stewardship though an awards program that recognizes project sponsors that
implement programs that preserve and enhance watershed health.
g) Develop partnerships with business, residents, NGOs, Cities, the County, Agencies, schools and
private entities throughout the watershed to leverage opportunities for watershed stewardship.
Stewardship management gaps include:
• An overarching environmental protection group is missing in the watershed.
• Collabaration between local jurisdictions, agencies and local environmental organizations.
• Political support for the watershed management process.
• Watershed-specific educational message to educate decision makers, stakeholders and the public.
Citizens and environmental groups are currently active in the watershed and current educational programs
promote awareness of watershed issues. However, the WPG has indicated that more outreach is needed
to policymakers to encourage additional management, particularly to minimize impervious area and
preserve and restore riparian habitat. This plan provides recominendations for organizing a
comprehensive watershed implementation and stewardship effort that would be led by a collaborative
watershed council. Recommended outreach efforts include education for local boards, educational
materials, technical and policy-oriented workshops and programs, and management partnerships. These
��� �� recommendations are discussed in Section 6.6.
�
�
5.3 SUMMARY OF MANAGEMEIVT GAPS AND NEEDS
Several management gaps emerged from the above evaluation of current regulations and key manageinent
building blocks and gaps. Management opportunities can be identified that address these management
gaps and build upon past and current management efforts. The following major management gaps were
identified through the above evaluation:
• Planned efforts to address water quality impairments, except for the lagoon impairment, within
the next decade.
• Specific requirements and implementation/enforceinent methods for the 2007 Order LID
requirements.
• Lack oi quantitative measures and assessment methods (involving simple, cost-effective
spreadsheet-based modeling tools) for management practice performance to meet stormwater
manageinent requirements for pollutant reduction.
• Hydromodification management in developed areas not siated for redevelopment and restoration
of stream channels impacted by past development.
• Methods to reduce upland sediment loading from construction sites beyond currellt regulations
and enforcement.
• Restoration of existing impacts, including loss of riparian habitat (including matures trees and
other natural vegetation along streainbanks), wetland habitat, and aquatic habitat.
• Natural floodplain restoration,
j�j rmew�
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Agua Hedionda Watershed Management Plan — Final August 2008
• Land protection that addresses all priority issues in the watershed, including water quality,
' channel stability, and habitat.
• An overarching watershed organization that coordinates all watershed management efforts.
Opportunities to track other efforts and provide outreach and support were also identified; these
opportunities are addressed as part of this plan, but the above management gaps represent where this
WMP is likely to provide the most benefit while building upon past management efforts. For each gap,
this plan provides opportunities to protect and restore watershed functions. Cooperation among
jurisdictions, NGOs, and people who live and work in the watershed will be needed to fully address the
above mauagement gaps.
a ��
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Agua Hedionda Watershed Management Plan — Final August 2008
6 Recommended Watershed Management
Opportunities
This section presents the management opportunities identified to achieve the WPG's goals and objectives.
These opportunities were selected to address priority issues discussed in Section 4, build upon current
management efforts, and resolve the management gaps outlined in Section 5. This section is organized by
the following management types (Sections 6.1 through 6.7):
• New Development Site Management
• Preservation and Riparian Buffer and Wetlands Restoration
• Stream Restoration
o Stormwater BMP Retrofit Projects
• Development of quantitative methods for assessing management practice performance for
meeting pollutant reduction targets
• Citizen Stewardship/Public Outreach
• Funding and Sustained Support
After each of these management types are introduced, Section 6.8 describes how Tetra Tech selected
focus areas where different management types would complement each other and, if implemented in
concert, provide greater watershed bene�ts.
� At the end of each section, key implementation actions are listed for the opporiunities. It is important to
note that restoration and BMP retrofit projects may require the following permits:
• Coastal Development Permit for construction within the Coastal Zone
• Section 404 Permit froin the U.S. Army Corps of Engineers construction impacting to
jurisdictionai waters of the U.S.
• 401 Water Quality Certification from the RWQCB for conditions placed in the Section 404
Permit to protect water quality
• Streambed Alteration Agreement from Califonlia Department of Fish and Game due to impacts to
jurisdictional wetlands and streambeds
• Local Development Permits (i.e., grading, building or other construction related pennits)
Proposed watershed management projects may also require an evaluation under the California
Enviromnental Quality Act (CEQA), which requires state and local agencies to evaluate the
environmental iinpacts of their actious. It a project involves the use of federal funds, an evaluatiou under
the National Environmental Policy Act (NEPA) may also be required.
6.1 IVEW DEVELOPMENT SITE MANAGEMEIVT
New development has a significant potential to exacerbate existing watershed impacts, or even create new
ones in relatively unimpacted streams. Development can increase pollutant loading rates in runoff, and
can also increase the frequency and duration of erosive flows in stream channels. Appropriate site
manageinent can partially or even fully initigate development impacts, depending to a large degree on
how aggressively they are iinplemellted. Site management measures can meet several of the WPG's goais
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Agua Hedionda Watershed Management Plan — Final August 2008
= and objectives, including #lb (design and construct new developments, recreation areas, etc., in a manner
that minimizes impacts on watershed functions, including minimizing impervious areas) and all of
objectives under Goal #4 (support compliance with regional, state, and federal regulatory requirements).
Measures can also support Goal #2 (protect, restore, and enhance habitat in the watershed) depending on
whether riparian area and habitat protection are included in site management.
Many of the following sections focus on specific opportunities identified through watershed-wide
surveys. New development/redevelopment site management, on the other hand, is an ongoing process
related to current or potential future regulations, and the interpretation and enforcement of those
regulations. Two aspects of site management are discussed:
1. Irrigation requirements (for reducing irrigation return flow)
2. Site stormwater management
Irrigation Return Flow
Irrigation retunl flow is likely an important component of nutrient impacts to the watershed and lagoon.
Under natural conditions, many Agua Hedionda creeks would be dry much of the time, but low flows
persist throughout the year. Irrigation in developed areas of the watershed exceeds the capacity of the soil
and vegetation to evaporate and transpire the applied water, so excess irrigation water flows through
shallow groundwater to adjacent streams. Low flow monitoring data (e.g., Buena Creek) show highly
elevated concentrations of both total phosphorus and total nitrogen, and is correlated with developed areas
of the watershed. Lawn and landscaping fertilization is likely an important nutrient source in shallow
groundwater. Reducing irrigation return flow impacts has two separate components — reducing nutrient
loads at the source, and reducing return flow itself.
Several toois can be employed to reducing fertilizer use at both new and existing development sites,
� including:
t:
� Homeowner education about the impacts of over-fertilization
• Encourage or require soil testing to determine proper %rtilization rates
• Certification and training of lawn and landscaping care companies to require appiication of
fertilizer at appropriate rates, and prevent misapplication to impervious surfaces
Irrigation cannot be eliminated from the developed landscape of the Agua Hedionda watershed; it is
essentially required by California law (Public Resources Code 4291) for fire protection around building
sti-uctures. A 100-foot "minimum defensible space" must be maintained around housing structures,
including a 30-foot perimeter "Home Defense Zone" which must have few trees and vegetation with high
moisture content. However, this does not imply overwatering; in fact, the County of San Diego
Department of Planning and Land Use recommends using drought tolerant plant species and providing
irrigation only when necessary (San Diego County, 2008).
If irrigation meets but does not exceed demand, then irrigation return flow can be greatly reduced or even
eliminated. However, low water rates provide little incentive to conserve water, and irrigation water use
comprises about 50 to 70 percent of total water use (Carlos Michelon, San Diego County Water
Authority, personal coinmunication, March 4, 2008). Califoi7lia Asseinbly Bill 325, the Model Local
Water Efficieut Landscape Ordinance, went into effect in 1993 and specifies rest�ictions on irrigation
throughout California; however, adherence to these restrictions appears to be liinited. Rulemaking is
cun-ently underway to strengthen the 1992 requirements by 2010.
Irrigation retui-�7 flow can be reduced, and perhaps nearly eliminated by iinplementing the foliowing
measures:
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Agua Hedionda Watershed Management Plan — Final August 2008
• Stronger enforcement of the Model Local Water Efficient Landscape Ordinance in its current
form, and adopting and enforcing the pending update
• Property owner education about the impacts of irrigation return flow
• Pilot programs to test innovative technologies for sensing irrigation demand and reducing water
use
• Explore the possibility of cost-sharing for technologies that reduce water use
Stormwater Management
Providing adequate sediment and erosion control practices during site construction is a critical part of site
management for protecting water resources. While active construction sites are usually developed and
stabilized within a relatively short time period, the construction phase of a project has an especially high
risk for impacting water resources. Soil erosion rates from uncontrolled construction sites can be
extremely high, especially if gullies or washouts develop. Fortunately, the managing authorities in the
Agua Hedionda watershed already have strong and well-developed sediment and erosion control
programs (David Hauser, City of Carlsbad, personal communication, October 2007). These programs
should continue to be supported and maintained to ensure compliauce with requirements, thus reducing
the risk of construction phase impacts to water quality. See Appendix A for more information about
sediment and erosion control regulations.
Post-construction stormwater runoff can be managed in many ways, and the combination of site design
and BMP selection can lead to a p1a11 that minimizes stormwater impacts to water resources. This section
provides an exploration of projected benefits of two different storinwater management scenarios — one
based on basic adoption of LID practices as specified by the 2007 Order (called "Basic LID"), and
�- � another based on a higher level of LID implementation (called "Enhanced LID"). The degree to which
� LID practices will be required in the future depends on many factors. There is currently some uncertainty
in the Agua Hedionda watershed about future requirements — implementation of pending TMDLs may
include a stormwater management component, with recommendation for specific BMPs to optimize
reductions for target pollutants. Communities may elect to implement LID to varying degrees. The
modeled LID scenarios should not be interpreted as extremes in design, uor should the results be seen as
absolute. Many other scenarios with varying degrees of LID implementation could be conceived, and
pollutant removal performance is based on central tendencies from monitoring studies, but inherently
coutains some uncertainty. The scenarios also use generic site assumptions, but in reality each site is
unique and presents its own opportunities for adoption of LID practices.
Assumptions for each of the two scenarios were developed for the following representative land uses:
• Medium Density Residential
• Multi-family Residential
• Commercial
• IndustriaUWarehouse
The selection of treatment practices was influenced by the following factors:
• Existing post-construction stormwater management requirements
• Constraints related to the physicai environment of the watershed that limit the use of certain
practices
• For each type of site modeled, treatment practice feasibility with respect to site layout and
economic considerations
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Agua Hedionda Watershed Management Plan — Fina! August 2008
Each of these is discussed, followed by a suinmary of the LID scenario analysis. The following
` information used for treatment practice selection has appiication to stormwater maliagement and LID in a
broader sense, and forms the basis for many of the recommendations in the Prioritization section. Details
of the analysis are presented in Appendix J, including site specific assumptions, BMP performance
assumptions, and the modeling framework used for the analysis.
Post-construction Stormwater Management RequiYenzents
Regulations are the primary driver for shaping site stormwater management, and well constructed
requirements can be used to implement watershed-wide goals. The 2007 Order stipulates that local
governments must encourage the use of LID in new development and redevelopment projects. The
County of San Diego has developed a Low Impact Development Handbook to provide guidance during
this initial phase of LID impleinentation. The Manual states that there is "a lack of research and pilot
projects in an arid environment." With the few LID examples in the region, there is a lack of project
information or lessons learned.
At a minimum, developers must meet the existing design criteria from the 2001 Order, which include:
Volume-controi based BMPs that provide treatment to the voluine of runoff produced from a 24-
hour 85th percentile storm event
• Flow-control based BMPs that provide treatment for a specified flow rate based on a set rainfall
intensity (either fixed or dependent on the local 85th percentile storm)
Additional peak flow requirements are specified by the 200'7 Order (matching pre-development peak
flows up to the 10-year 24-hour storm event). All site designs under both scenarios are assumed to meet
the requirements of both the 2001 and 2007 Orders as stated above. However, the extent of required
�.- - future LID adoption is unknown, so the two LID scenarios vary in the assumed level of LID adoption.
�
Environmental Const��aints
Rainfall. The Agua Hedionda watershed gets approximately 10 to 13 inches of rainfall per year. Many of
the streams in the watershed are dry except during the large, infrequent rain events (or their baseflow is
maintained artificially by irrigation retuni flow). Techniques that require substantial water iuput to
inaintain a permanent pool (e.g., wet ponds and wetlands) are not likely to be seen as sustainable by some
stakeholders, and have another risk — if water rates increase, ar if the pool is maintained by irrigation
retunz flow that dwindles under irrigaiion use restrictions, the pools could dry up and become a sediment
and pollutant source. Other tecivliques developed for more humid environments (e.g., bioretention) may
not perform as expected without pennanent irrigation. Note that the arid environmental constraint affects
not only ilew development projects, but also redevelopment and retrofit projects.
Fire. As noted in the discussion regarding irrigation return flow, there are state fire safety rules that limit
the type and density of vegetation within 100 feet of building structures. These regulations may
potentialiy aifect the feasibility of some practices that rely on vegetation for treatment; especially those
that work best when distributed throughout a site. When selecting plants for BMPs, developers may need
to strike a balance between appropriate hydrologic requirements and fire resistance. Note that this
constraint affects not only new development projects, but also redevelopment and retrofit projects.
Slope. The steep slopes present in much of the watershed pose a challenge to minimizing the use of fill
material (because fill is often used in construction to maximize buildable area). Fill slopes are designed
specifically to minimize infiltration of water into the fi11 and drain runoff off the land surface. As a resuit,
the engineered compacted soil is not conducive to infiltr•ating excess runoff on steep slopes. Tetra Tech
analyzed the developable land in the Agua Hedionda Watershed per designated future land use, and
determined that slope is not a major constraint for new development requiring stormwater mauagement.
Figure 6-1 depicts the areas projected to develop in the watershed in green, arange, and pink. Green
indicates areas with slope less than 15 percent, orange is used for slopes 15 percent to 25 percent, and red
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Agua Hedionda Wate�shetl Management P/an — Final Aug�st 2008
s f'or slopcs grcater tl�an 25 percein. As the figure dcmons[ratcs, almosl all oflhe de�elop�ble land has a
sbE�c of Icss �han 1 5 percei�t Thc only c ccptSon is n thc iar castcrn priit oF thc watcrsM1cd, whic6
s anliciVaied to dovGop as Voy Low Dcnsity Rcvidrntial (c v-hamhcd n a) znd would not bc
sidc-cd a pri rCry project u��der ihe 2001 a�d 20U"1 Orders. However, slope i an in�portant
consido-ation at individual sitcs, and may Ilmit ihc d�oicc of n�anagcmcnt pracficcs.
Soil intiliration 2ate. Mairy LID practices rcly u intiltratio�� o1'sturmwa�cr �vnoft', a trcatment metliod
ch2� ie highly cffcctivc for pollutant trcatmcnt and�volumc rcduction_ inFlvation trcnchcs and fnfiltration
besns rcly on good undcrlying soil infiltra[ion ratcs, whilc lmat�ncnt by biorcicn�ion and porous
pavcrticnt tcchnologics ls nprovcd wlicn infiltration is supportcd. Ilowcvcr, soils witl� low o cry low
infil�ratfon rates maY slow�percolation ofstorcd runofflo ibe point oFbcing ineffcctivc. Por czamplq in
thc Picdmon� rcgion o{Hic Souihcv.v-tcm U.S. whcm hcuvy day so31.v- dominatc, a mdcrdrein rystcm is
spw�ificd f r biorctcntion (North Carolina Uivision of WatcrQualiry, 200�)- On�thc othcr han<L many
., n Scattic, WA with �nnppcd soils sl�owfng low Intiltration ru[cs w c£ound to supyort liigherratcs
tM1an�cxpccted_ and BMPs placcd a� thcsc si[cs complc[cly drain and infiltratc runoff witl�in ]2 hom-s
(Tracy Tackctq Scattic PubGc UtSGtfcs, personu] c -catfon, Iunc 22, 2003). Tcv-si TccM1 e�alymd
�M1c dcvclopablc land in �hc Agua Hcdionda WatcrshcA�per dcsignatcd Futmro land usc, and dctcrmincd tha�
. oil infl[raGon ratcs v nza�or consvaint for usfrin LI� tor nvw dcvdopincni rcquiring sionnwatcr
managcineni_ As sccn in�Figm'e 6-2. most i�fchc devGopabic arca has a soil hydrologic grot�p of [J
(shown 9n rad). whfch has vcry luw inGl�ratSon ratcn. Most of �he rcmainfn� dcvclopablc lanal has yroip�
O. ..e.E�.�.�.�. 6 5
Figure 6-1. Slope Class for �evelopable Land
Agua Hedionda Wate�shed Management P/an - Final August 2008
C soils (shown in orangc), which M1avc low inFltration ratcs. A vcry s iall por[ion ofdcvclopablc land
kas 6 soils (5ho � ycllow), which have modcratc fnlSltr��iov asten.��The ubiquitous prc-cnce ofeofls
wiH� low o cry low I��Filtratlon ratcs i� s proJccicd For F�tum dcvclopmant may climu�atc alto�.ctl�o�
ihc IJU practiccs tliat rcty cxGusivcly o inFllvation, and ii �_ v tls cost ofothcr practiccs (�uch xs
bio -etcnGo�� end Largcr po s- pe� nt�i �sLalLatione) where an underdrain system may nced to be
installcd and conncctcd toTa �storm draina�c rystcni.
Si/c Spec fic Procdvc Fons)h]/[q�
Sitc land u; - nnd layout of buildings, sidcwalks, and driving surfaccs hos a stron� intlucnw on what
practices can bc incwpoiaxci. If a siw 6as a high pcmcntagc of impc�vious arca, chc'c is limitcd pervious
ia{or most st�uctival 6MPs. Thc iistribuGon oF thc imparvioiu a-� nlso a mpurtant Lactor: if tlic
mpervious area is concenxraicd. ir will bc more difficWc to usc disperecd LIO L3MPs thai ircat runofi
ne��cr ihe source; by ihc s�a�ne tohcn, i� may be aasicr to route �z�nol'Fto wall-placed BMPs.
As discusscd prcviousty, n. iatysis o{two scormw�amr n� iagcmcnt s- s(Bo.cic L/O snd Enhn.00c.d
L/D) was perfomicA For four ��presentativc l�nd uses to explorc poeontial�bcncfils to watcr resou�nc
�rotcction. TM1c land u caccgorics and impervious aica assu nptions aic shown in Teblc 6-1. Thc
analysis is prescntcd in dmail in APPcndix J.
O...r.��.�.��. 6 6
Figure 6-2. Soil Hydrologic Group for Oevelopable Land
Hedionda Watershed Management Plan — Final August 2008
The Basic LID scenario is based on the combined use of vegetated swales (or bioswales) for water quality
treatment of part of the site, and an extended dry detentiou basin treating all of the site, providing both
hydrologic control for the 2001/2007 Order requirements, as well as water quality treatment beneiits. The
site assumptions and configurations are identical to those used in the Agua Hedionda Watershed
Modeling and Geomorphic Analysis Report (Tetra Tech, 2008b) for the same land uses. The Enhanced
LID scenario begins with the Basic LID scenario assumptions, but assumes a higher level oi treatment,
balancing feasibility and cost considerations. For instance, bioretention is not used due to the uncertainty
regarding proper vegetation and potential increased cost if an underdrain system is required. Porous
pavement was included but not used extensively, again due to uncertainty about infiltration. Large
cisterns for irrigation water were included for the Multi-fainily and Commercial classes, where the
�`� combination of large roof surface area and centralized irrigation systems are assumed to make the practice
�_ more cost effective. Some of the scenarios assume impervious area reductions as well. The following
specific changes implemented in the Enhanced LID scenario include:
• Mediuin Densiry Residentiai — a cluster design is used, grouping the housing units closer together
on smaller lots, and leaving one-third of the site as undeveloped open space. Impervious area is
reduced by decreasing driveway length, sidewalk use, and overall road footprint.
• Multifamily Residential — Impervious area is reduced somewhat by more efficient layout. Porous
pavement is used for all sidewalks. The swales treat a greater proportion of the site. Large
cisterns capture roof runoff, and reuse the water for irrigation.
• Corrunercial — Porous pavement is used for large fraction of the parking area. Large cistenis
capture roof runoff, and reuse the water for irrigation.
• Industrial — The most challenging site, with layout constraints and little economic incentive for
cisterns for irrigation. Porous pavement parking spaces is assumed (a small fraction of the total
paved surface), and the swales treat a greater proportion of the site.
Further details regarding site layout assumptions and BMP treatment are discussed in Appendix J. The
results of the analysis estiinate that implementation of Basic LID treatment practices would reduce
sediment loads by about 60 — 70 percent, and fecal colifonn loads by almost 90 percent. Total nitrogen
and total phosphorus removal would be considerably less, ranging from 35 — 45 percent and 25 to 30
percent, respectively. The Enhanced LID techniques iinprove sediment reinoval to some degree for most
of the develop classes, but nitrogen and phosphorus removal are improved considerabiy. Multi-fainily
Residential and Commercial land uses under Enhanced LID provide additional storm event peak flow and
duration reductions due to the use of large cisterns, and are likely to reduce risk of downstream channel
erosion over the Basic LID design. More results are shown the LID Implementation Benefits section
" (7.4.1) and in Appendix J.
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Table 6-1. LID Scenario Land Use Categories
Hedionda Watershed Management Plan — Final
/1:
- The following actions provide support and guidance for successfuily implementing the recommendations
in this section as well as management gaps and needs identified elsewhere in this report. Most of these
items are related to interpreting and enforcing the 2007 Order.
• Revision of local codes to incorporate recommended Basic LID techniques.
• Application of Basic LID techniques include reducing and disconnecting impervious area;
extended dry detention; swales or bioretention; and stream buffers (included in the 2007 Order).
• Tracking compiiance with stormwater management and LID.
• Review of the site plan and engineering plans for compliance with LID requirements (included in
2007 Order).
• Developmeut of quantitative methods (involving siinple, cost-effective spreadsheet-based
modeling tools) for assessing management practice performance for meeting pollutant reduction
targets.
• Implementation of the Enhanced LID techniques %llowing the adoption of new hydrology and/or
new water quality requirements.
• Additional revision of local codes, as needed, to meet future, more stringent requirements.
• Feasibility studies for cisterns, porous pavement, and bioretention without irrigation. If soil
infiltration rates are found to be higher than expected and support bioretention and porous
pavement without underdrain systems, then feasibility studies should be expanded to include
infiltration basins on sites with lower slopes and low risk for grade failure.
• To address irrigation return flow, stronger enforcement of the Model Local Water Efficient
� Landscape Ordinance in its current form, and adoptiilg and enforcing the pending update.
• Prograins to support reduced use of irrigation for developed sites, including property owner
education, pilot programs to test innovative technologies for use reduction, and cost-sharing for
technologies that reduce water use.
• As discussed in the Agua Hedionda Modeling and Hydromodification Report (Tetra Tech,
2008b), current BMP requirements, including those specified under the 20070rder, may not be
sufficient to protect from hydromodification of downstreain channels. The need for additional
protection measures should be explored during the development of the San Diego Regional
Hydromodification Plan.
Implementation strategies to accomplish most of these actions are described in more detail in Section 7.
6.2 LAND ACQUISITION, RIPARIAN BUFFER RESTORATION, AND
WETLANDS RESTORATION
The Agua Hedionda Watershed Manageinent P1an provides an opportunity to identify 1) reinaining high
quality habitat aud 2) opportunities to restore lost habitat. Land acquisition prevents remaining natural
areas from being developed or disturbed; this type of inanagement also maintains the existing quality of
the natural areas through stewardship activities, such as invasive species control and enforcement of
restrictions on public use. Riparian buffer restoration seeks to remove invasive species and revegetate
native riparian vegetation along streams and other waterbodies, Wetlands restoration reestablishes
wetland hydrology and vegetatioll on land where historic wetlands have been impacted or destroyed.
Some overlap occurs between these practices and stream restoration, but generally stream restoration
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focuses more on restoring the shape and function of a stream through instreain controls, recontouring, and
other engineering practices.
The preservation and restoration opporlunities were evaluated based on screening criteria that measure
how well the opportunities meet the goals and objectives of the W1VII'. These opportunities particularly
address Goai #2 while also addressing water quality concerns relating to Goal #3. Indicators identified to
measure achieveinent of these goals were used when selecting and evaluating these opporiunities. The
opportunities considered for land acquisition, buffer restoration, and wetlands restoration are collectively
referred to hereafter as "AqRest" opportunities.
6.2.1 Screening Criteria
The screening criteria used for the AqRest opportunities identify conditions in the watershed where
management would be inost successful at achieving the WPG's habitat objectives under Goal #2 and
water quality objectives under Goal #3. Table 6-2lists the screening criteria developed for the purpose
of selecting and prioritizing AqRest opportunities and illustrates which criteria were used for each type of
opportunity. Several of the screening criteria are used to prioritize more than one opportunity. In the
Agua Hedionda Watershed Acquisition and Restoration Report (Tetra Tech, 2008a), details are provided
on how screening criteria and associated data were used to evaluate each type of opportunity.
The data and screening criteria were used to calculate metrics to measure achievement of the WPG's
objectives. A metric is defined, for the purposes of this evaluation, as a measurement that can be used to
identify and prioritize management opportunities according to the goals and objectives. Metric methods
can vary in complexity, from the count of species observations per subwatershed to a set of rules
involving treatment status and distance from invasive species infestations.
� The metrics were used to develop a scoring system that prioritized inanagement opportunities. A separate
scoring system was developed for each type of management. The scoring systems were linked in some
cases, where a metric calculated for one type of management heiped better prioritize allother type of
management. For example, the priority subwatershed metric developed for the land acquisition
prioritization was also appiied to the buffer and wetlands restoration priaritization to identify restoration
opportunities that provided connectivity to existing habitat. Foliowiilg Tetra Tech (2008a), the WPG
provided comments on the screening criieria and the updates were made to the prioritization and scoring
methods, as detailed in Appendix B. Screening criteria added following these commeilts are noted in
Table 6-2.
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Table 6-2. Initial Screening Criteria Selected to Evaluate �and Acquisition, Buffer Restoration,
` and Wetlands Restoration Opportunities
e..,.
�:
Screening Criteria / Data Land Acquisition ' Buffer Restoration Wetlands Restoration
SC-1 Natural Area ✓
SC-2 Protected Natural Areas ✓
SC-3 Unprotected Natural �
Areas
SC-4 Existing Terrestrial �
Habitat
SC-5 Invasive Species Extent �
and Status of Treatment
SC-6 Riparian Habitat
(Existing and Estimated ✓
Historic Extent)
SC-7 Priority Subwatersheds ✓ ✓ ✓
SC-8 Restoration Reaches ✓ ✓
SC-9 MSCP/MHCP Species ✓
SC-10 Aquatic Habitat ✓
SC-11 Wetland Function
using California Rapid ✓ ✓
Assessment Method
SC-12 Lagoon �
Subwatersheds
SC-13 Erosion Hazard Index ✓
SC-14 Riparian Buffer or
Wetland Restoration ✓ ✓
Opportunity
SC-15 Riparian Restoration �
Opportunity
SC-16 Wetlands Restoration �
Opportunity
SC-17 Mature Riparian Trees ✓ ✓'
SC-18 Sewer Constraints ✓ ✓
SC-19 Road and Bridge � �
Constraints
SC-20 Priority and Linkage � �
Subwatersheds
SG21 Coastal �
Subwatersheds
SC-22 Stakeholder Priority ✓� ✓
SC-23 Total Opportunity Area ✓�
' These screening criteria were added following stakeholder comments on Tetra Tech (2008a).
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Agua Hedionda Watershed Managemeni P/an - Fina/ Auqust 2008
As a paralld cffort to idcntify AqRcst opportuoitics. Tctra Tcclv askc i WPG n mbcrs, r ago�cics,
co�scrvation o�gznizations, and otha� stakcholdc�s m rccommo�d loca[ions in the watcrsheds lor land
cquu3tio�� a��ci presarvat3ov a well a wetluncls restoralion. Unclar tha stalccholdcr prlorfty s ing
ritcria, thc stakcholdcr rcconunc��dcd opportuniKcs ti�ac c�ntaincd nmtural a wctlands restoration
oppottuniiy were b'�ven u higher score under cither tho land acquisi[ion or weUands restoralion
prioritizs�Ka��. For a suUset ol'these oppurtunitics, siz�keholdars yrovldcd uifoni�eGan ui� the location.
amcnitics, and siatus of managcmcnte which is providcd in thc Managcmcnt Opportunity Databasc (a
spreadsheet tool that will be �iveri w deciaion �nakers with ihc WMP).
6.2.2 Prioritization
6.2.2.1 Land Acquisition for Preservation
Par els with uvpru�ected nsmral ¢ were considered opporwniGes lor laud z cyuisitio�� z nd hvbitvt
aev
prescrva[ion withfn thc watcrshcd_ PrioriGzation £ocuscd on cvaJuating Uoth thc quality o{thc parcc]
idemi�ed for preservntion ¢n i the quality ofclic surrounding hzbitat. Thc mcthods uscd �o score and rank
thc parccls idcntiticd For pres-crvation a c dcscrlbcd in Tctra Tcch (2003a). A. indlcatc 1 nbovq tlicsc
_ ng n�cthods w u�datcd bascd on WPG conuncnts. IJccailcd scoring resWts arcprovidcd in �hc
cori crc
opporwniiY daiabasc provided with this Plan.
Figure 6-3. View into the headwater area of Lie Buena Creek watersh¢d as seen from Hardell
Lane. (Photo couResy of M. AshFord, Ashford Engin¢ering, Inc.)
O rE.ae.E�...�..�.
6-t t
Agua Hedionda Wa(ershed Management P/an - Fina/ Auqust 2008
Tablc 6-3 lists tl�n 25 �op ranhing land �acquissLion and prcscrvat9on opportuniGas buscd on thc r- vcd
scoring nicchods. Plnn og-Ic cl, cpmal c�sts a c providcd bascd on mc2hods ouclincA in "1'eva Tcch
(2008a�. These costs include Uie cosl [o preseive xhe land f�am furthcr development (acquisition cos-t)
and thc wst co n��agc LLic land in pcipcwity (cndowincnt cosQ. Long-tcnn n �agan�cnt r�ccds inay
inGudc invasivc�s�pccics convol, Frc prwrntion, romoval ofdiscased trees, enforcement ofrestrictions o0
public usc-, avd other maintevance activities.
Figure 6-4. Existing Naturel Riparian Habita[ - Agua Hedionda Creek (Reach '17)
Thc 25 LOP �'ankiiig land acquisition and presc�vation oppo�Yuniiic. r�ngc f-oni abowt 2 ro 50 acres and
�cludc 38"l acres in lotal. Thc coat of purchasivg and n n�ainin_ a�l l top rankine pascls is cstfmatcd m
angc frnm $3A to $95 million f r fcc s mplc acqnisi�io�� "''fhia co.vc inay bc rcduccd through purchasc ui'
conservation easemenls_ bargain sales, ete 'I'he lolal cosl pe s esti�Yia�cd to r c fmn� 545A00 to
r acrc i
52A0,000. Thc variaGon i� -�st per acquisitfoii is duc to tM1c dl£{crc��ccs i� caluc bctwccn riparian.
upland, �nd coastal arcas. �Ripariun aroas xiro typicaliy undcvclupablc and�thcrcforc Icss cxpc� v to
cquiro than upland a._; land ii astal a- , s tcnds «� be n cxpcnsivc than land i� in�land arcas.
Since these estimaecs�v'e planning�ievel, concepwal costs. �hey�shoulcl not be used f r londing alloeation
m a capi[al budgat plan but czn ba uscd to csHmatc costs for a grant application.
Many o[hcr high quality land acqwsition opportu��idcs- c ist t6roughout thc watcrsiicd: howwcr, for
practical purposes of pmparation oClhis walershed-wide plan, and 1'or comprcheosfvc budgcting pwposcs,
>nty thc top 25 a c highGghtc 1 tM1ert n cct tl�c brosdcr watcrshcd ol�l«Gvcs. Throughout thc watcrshc.d.
evcral prope�ttos exist that w mldpro�ide benefits lor habieat pro�enion, wildlifc movc�ncn�, aod
cn�iangercd spcdcs suppor[. As thc stakd�oldc�c n c forwnrd, thcsc propertfcs c n bc eddcc3 to thc
acquisicion list as appropriacc. Spccific opportunitics w considcr indudc I_A-21. LA-29, LA-31, LA-34.
O. .....E�... ��,�. 6-'I 2
Agua Hedionda Watershed Management Plan — Final
2008
- LA-39, LA-64, LA-68, LA-87, LA-92, LA-108, LA-111, LA-114, LA-123, LA-129, LA-133, LA-135,
' LA-140, LA-168, LA-201, LA-208, LA-219, LA-286, LA-292, LA-345, LA-375, LA-532, LA-543, LA-
559, and LA-637.
The following actions will be required to successfully impiement the recommended land acquisition and
preservation opportunities:
• Field evaluation
• Identify project proponent (site-by-site)�
• Landowner outreach
• Coordination with cultural resources priorities
• Secure funding sources
• Identify/secure stewardship organizations
• Develop stewardship plan
• Purchase Property
• Annual acquisitioi�/restoration workshop
• Update/maintain prioritization tool
Implementation strategies to accomplish these actions are described in more detail in Section 7 and
Appendix H.
�
� Note: Project proponent is one or more entities that wishes to acquire the project site. The proponent may be a
local government or other agency, an NGO, and/ar a private sector entity that has initigation needs.
O TETRATECH� INC.
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6.2.2.2 Buffer Restoration
Riparian habitat exists between stream channels and upland areas and typically intersects with the
floodplain. Riparian buffer restoration involves restoring natural vegetation where riparian habitat has
been previously impacted or destroyed. Riparian buffer restoration will provide an important
management strategy, particularly when coupled with preservation, bioengineering, and BMP retrofit
opportunities. Much of the riparian vegetation in the watershed has been disturbed; however a significant
area of land exists where it can be restored.
Riparian buffer restoration management measures, as considered in this management plan, would include
restoraiion (i.e., planting) of riparian vegetation. Appropriate plant communities will need to be selected,
and a planting plan should be developed for each site that identifies planting zones based on hydrology,
soils, slopes and other factors) for the selected plant communities. Construction activities will involve
invasive plant removal, grading, soil conditioning, planting, and soil stabilization. Maintenance and
monitoring will be required to ensure success of the restoration. Section 6.3 recommends stream
restoration opportunities that use additional measures to restore stream functionality.
It will be important to prioritize riparian buffer restoration where it will provide the greatest benefits for
wildlife populations and water quality. One of the WPG's objectives is to enhance and restore riparian
habitat. Restoration near or adjacent to existing habitat will directly address this objective because the
existing habitat quality will be enhanced by connectivity to the restored areas. When implemented
upstream of stream restoration projects, riparian buffer restoration will help protect existing and restored
aquatic habitat downstream. Buffer restoration can also enhance efforts to protect mature trees in riparian
corridors and will help to establish a new generation of Coast Live Oak and other priority riparian species.
Riparian buffers will also provide erosion control and some removal of stormwater pollutants.
� To identify areas where riparian habitat could be restored, Tetra Tech estimated the historic and current
extent of riparian habitat. This area was estimated using the 100-year floodplain, vegetation cover GIS
data, and aerial photographs. The estimated extent of riparian habitat, existing and historic, was termed
the targeted buffer area and is shown in Figure 6-5. Undeveloped parcels without naturai vegetation were
identified as opportunities for riparian habitat restoration.
Figure 6-5 displays the locations of the buffer restaratiou opportunities and groups the opportunities into
three priority levels based on the updated scoring. Table 6-4lists the 27 top ranking buffer restoratiou
opporiunities based on the revised scoring methods; these opportunities are displayed as the high priority
level in Figure 6-5. The methods used to score and rank the opportunities are described in Tetra Tech
Figure 6-5 (2008a). As indicated above, these scoring methods were updated based on WPG comments.
Detailed scoring results are provided in the opportunity database provided with this plan.
Planning-level, conceptual costs in Table 6-4 are based on methods outiined in Tetra Tech (2008a).
These costs include preserving the land from further development (acquisition cost), restoring riparian
vegetation, aud managing the land in perpetuity (endowment cost). Long-term management needs may
include invasive species control, fire preveution, removal of diseased trees, enforcement of restrictions on
pubiic use, and other maintenance activities. Since these estimates are planning-level, conceptual costs,
they should not be used for funding allocation in a capital budget plan but can be used to estimate costs
for a grant application.
The 27 top ranking buffer restoration opportunities range from about 0.2 to 29 acres and include 129 acres
in totaL The estimated cost of pur-chasing through fee simple acquisition, restoring, and maintaining all
top ranking parcels is estimated to range from $10 to $19 million. This cost may be reduced through
purchase of conservation easements, bargain sales, etc. The total cost per acre is estimated to range from
�42,000 to $160,000 per acre. The variation in cost per acquisition is due to the differences in value
between public versus private ownership. Riparian areas are typically undevelopable and therefore less
Q �rw►,vrH
6-16
Agua Hedionda Watershed Management Plan — Final
Auqust 2008
expensive to acquire than upland areas. Some parcels are owned by public entities and, therefare,
` acquisition costs for these parcels were assumed to be zero.
The following actions will be required to successfully implement the recoinmended buffer restoration
opporiunities:
• Project proponent' identification (site-by-site basis)
• Field evaluation
• Landowner outreach
• Contact ACOE and other permitting agencies
• Coordinate with trails and infrastructure
• Coordination with cultural resources priorities
• Preliminary design and cost estimate
• Secure needed permits
• Secure funding
• Secure stewardship organizations
• Final planning and design
• Develop stewardship plan
� Implement Projects
��� � • Annual acquisition/restoration workshop
• Updating/maintaining prioritization tool
Implementation strategies to accomplish these actions are described in more detail in Section 7 and
Appendix H.
� Project proponent is one or more entities that wish to conduct stream buffer or wetland restoration on the project
site. The proponent may be a local governlnent or other agency, an NGO and/or a private sector entity that has
mitigation needs.
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6.2.2.3 Wetlands Restoration
As discussed in Section 4.4, the Agua Hedionda watershed has inost likely lost the majority of its
historical wetland habitat. Wetlands restoration would seek to restore some of this lost habitat while
enhancing the connectivity of overall habitat in the watershed. Beyond habitat, wetlands restoration
would also restore the water quality functions of wetlands, including flood control, sediment trapping, and
nutrient attenuation.
The types of wetlands restoration measures will vary depending on site-specific characteristics, however,
they will typically involve grading and excavation to restore wetland hydrology, invasive species
removal, and revegetation. Once properties are identified for landowner outreach and implementation,
the opportunities will need to be evaluated in the field and conceptual wetlands restoration designs would
need to be developed for each opportunity. Appropriate plant communities will need to be selected, and a
planting plan should be developed for each site that identifies planting zones based on hydrology, soils,
slopes and other factors) for the selected plant communities. Construction activities will involve invasive
plant removal, grading and excavation, soil conditioning, planting, and soil stabilization. Maintenance
and inonitoring wili be required to ensure success of the restoration.
Tetra Tech spoke with a number of mitigation bank managers during the development of the WMP, and
those managers generally indicated that wetlands restoration opportunities are difficult to find in the San
Diego area, and that coastal wetlands restoration opportunities tend to be both dif�icult to �nd and
expensive. To ensure that remaining opportunities are captured within the Agua Hedionda WMP, Tetra
Tech developed comprehensive geographic information system (GIS) screening methods that identified
undeveloped land where wetland vegetation has been cleared or where wetland hydrology has been
altered or destroyed. Tetra Tech also documeiited stakeholder recommendations for wetland restoration
opportunities to supplement the opportunities identified through the GIS analysis.
Figure 6-6 displays the locations of the wetlands restoration opportunities and groups the opportunities
into three priority levels based on the updated scoring. Table 6-5 lists the 12 top ranking wetlands
restoration opportunities based on the revised scoring methods; these opporiunities are displayed as the
high priority level in Figure 6-6. The methods used to score and rank the opportunities are described in
Tetra Tech (2008a). As indicated above, these scoring methods were updated based on WPG coinments.
Detailed scoring results are provided in the opportunity database provided with this plan.
Planning-level, conceptual costs in Table 6-5 are based on methods outlined in Tetra Tech (2008a).
These costs include preserving the land from further development (acquisition cost), restoring wetland
vegetation and hydrology, and inauaging the land in perpetuity (endowment cost). Long-term
management needs may include invasive species control, fire prevention, removal diseased trees,
enforcement of restrictions on public use, and other maintenance activities. Since these estimates are
planning-level, conceptual costs, they should not be used for iunding allocation in a capital budget plan
but can be used to estiinate costs for a grant application.
The 12 top rauking wetland restoration opporiunities range from about 0.2 to 21 acres and include 47
acres in total. The estiinated cost of purchasing through fee simple acquisition, restoring, and maintaining
ail top ranking parceis is estimated to range from $3 to $10 million. This cost may be reduced through
purchase of conservation easements, bargain sales, etc. The total cost per acre is estiinated to range from
$42,000 to $250,000 per acre. The variatiou in cost per acquisition is due to public versus private
ownership. Some parcels are owned by public entities and, therefore, acquisition costs for these parcels
were assuined to be zero. None of the wetlands restoration opportunities were in coastal subwatersheds
and, therefore, higher coastal property values were not considered.
Two promising wetlands restoration opportunities were added to the stakeholder recommended list after
the above analysis. These opportunities are both on California Department of Fish and Game (CDFG)
a��
6-21
Hedionda Watershed Management Plan — Final August 2008
-- managed ecological reserve lands. They are tidally influenced but function relatively poorly due to a
' number of factors, principally elevation and drainage. The creation of greater tidal channels and
vegetated marshlands in the present salt panne habitat areas is recommended to provide greater larval fish
production at Agua Hedionda Lagoon. It should be noted that soine of the higher flats are used by nesting
birds and thus some consideration should be given to how restoration can provide a net benefit instead of
replacing one resource or habitat with another (Keith Merkle, Merkle & Associates, personal
communication to Meleah Ashford, July 2008). The Management Opportunity Database provides more
details on these and other stakeholder recommended wetlands restoration opportunities.
The following actions will be required to successfully impleinent the recommended wetlands restoration
opportunities:
• Project proponent' identification (site by site basis)
• Field evaluation
• Landowner outreach
• Contact ACOE and other permitting agencies
• Coordinate with trails and infrastructure
• Coordination with cultural resources priorities
• Preliminary design and cost estimate
• Secure needed permits
• Securing funding
� • Secure stewardship organizations
• Final planning and design
• Develop stewardship plan
• Implement Projects
• Annual acquisitioi�/restoration workshop
• Updating/maintaining prioritization tool
Impleinentation strategies to accomplish these actions are described in more detail in Sectiou 7 and
Appendix H.
� Project proponent is one or more entities that wish to conduct stream buffer or wetland restoration on the project
site. The proponent may be a local government or other agency, an NGO and/or a private sector entity that has
mitigation needs.
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Agua Hedionda Watershed Management Plan — Final August 2008
6.3 STREAM RESTORATION
The stream restoration opporiuuities identified for the Agua Hedionda WMP support the WPG's Goal #2
— to protect, restore and enhance habitat in the watershed. The main focus of the stream restoration
projects is objective 2e — maintain stable streambanks and riparian areas to protect instream aquatic
habitat and priority tree species. The stream restoration projects also address objective 2b — protect,
enhance, and restore terrestrial habitat, especially existing vegetation in riparian areas by providing a
stable environment (i.e., stable streambanks). The stream restoration projects indirectly meet objective 2g
— maintain and protect lagoon habitat by limiting the delivery of excess sediment that is a result of mass
wasting of unstable streambanks.
Stream restoration opportunities focus on in-stream measures that meet these goals and objectives.
Stream restoration, as recoinineuded in this WMP, involves installing grade control structures within a
stream channel to achieve an equilibrium between sediment inflow and transport capacity of the stream.
Components of grade control structures include loose rock structures, channel lining, and more rigid
structures. Loose rock structures are recommended for stream stabilization to mimic the appearance of
natural stream beds. The traditional rock grade control structures would be low pro�le (approximately
two feet in height) and can be used to create riffles along the stream. It may be necessary to add fill to the
channel bed to begin to rebuild the bed elevation to au equilibrium state. Completely soft bank
stabilization measures are not recommended because the highly erosive forces evident in the watershed
would likely undermine these measures. Additional information on grade control structures is provided in
Tetra Tech (2008c).
6.3.1 Screening Criteria
Based on the geomorphic analysis in Tetra Tech (2008b), the most significant stream concern is the
widespread chanuel erosion. As discussed in 4.2, soine chaimel banks have experienced significant bank
erosion while other locations have been limited to undercutting at the toe of the bank. Numerous
locations have experienced channel incision (lowering of the channel invert). However, some amount of
erosion in the channel can be seen in inost reaches of the stream systems throughout the watershed.
Stream restoration opportunities were identified based on the following investigations:
• Field reconnaissance
• Stakeholder recommended opportunities
• Review of historic aerial photographs
These investigations were part of the geomorphic analysis described iu Section 4.2. The opportunities
were selected where evidence of significant channel erosion and instability was found and where
restoration was likely to have the greatest success at restoring functionality. Once opportunities were
identified, additional field reconnaissance was conducted to detenniue the specific restoration needs of
the streain reaches. Conceptual plans for each stream reach were developed that describe the measures
necessary to address channel erosion and instability.
At this level of conceptual design, Tetra Tech made the assumption that changes to the channel slope
would be adequate to achieve equilibrium conditions to restore streain functions. It is important to note
that additional hydrologic, hydraulic, and sediment transport modeling will be required to move to
detailed project design, and this modeling may show that channel modifications, such as chamlel
widening, may be also be necessary to achieve an equilibriurn condition.
a r�rR,►�
6-25
Agua Hedionda Watershed Management Plan — Final August 2008
6.3.2 Prioritization
The evidence of channel erosion and instability was used to identify restoration opporiunities that would
have the greatest likelihood of success for reducing channel erosion in the watershed. All of the stream
restoration projects identified herein are considered high priority projects. The WPG reviewed the
opportunities and concluded that all opporhuiities should be prioritized equally for implementation. They
represent those projects where the more significant stability issues are present as well as those that have
gained local interest. The location of the identified stream restoration opportunities is illustrated in Figure
6-7. The opportunities area is described in more detail in Tetra Tech (2008c) and 10 percent conceptual
plans are provided in Appendix C.
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Agua Hedionda Watershed Management Plan — Final August 2008
� No further prioritization of opportunities is provided; however it is understood that the various agencies
and organizations will be interested in pursuing projects that have different elements and support different
issues. Below is a description of the five critical factors that were identified and evaluated for each
project followed by Table 6-6 which identifies whether each factor applies to an individual project.
• WMP Goals
o Specific objectives for which the project was evaluated include:
(1) Objective 2b: Protect, enhance, and restore terrestrial habitat, especially existing
vegetation in riparian areas
■ (2) Objective 2e: Maintain stable streambanks and riparian areas to protect instream
aquatic habitat and priority tree species.
• Location
o Is the project located in the lower portions of the watershed? It is likely that projects located
in the lower watershed can have a greater impact on sediment trapping and prevent that
sediment from reaching the lagoon.
• Public Ownership
o Is the property identified far the project in public ownership?
• Critical Timing
o Does the channel exhibit concerns or issues that appear to require more immediate attention?
The following critical timing issues have been identifed:
�' ■ SR-02 — imminent failure of concrete grade control structure
�.
��� ■ SR-06 — channel is coinpletely blocked with debris at one location
■ SR-07 — development is imminent; property currently available
■ SR-11 — parking lot damage has occurred and will likely continue
• Multiple Benefits
o Can inultiple benefits be integrated with the project? The following multiple benefits have
been identified:
■ SR-O 1— provide flooding relief
■ SR-02 — coordinate with planned sewer line upgrades
■ SR-OS — restoration of significant watershed function prior to planned development
Based on the strong evaluation of project SR-02 and identification of a project proponent (the City of
Vista), this project was targeted for further development. For this project, Tetra Tech conducted
additional data collection and design to support development of 10 percent conceptual pians. This
information is provided in Appendix D.
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Agua Hedionda Watershed Management Plan — Final August 2008
- Planning-level, conceptual costs were estimated for the stream restoration opportunities (Table 6-7). The
conceptual cost estimates include mobilization, construction (grading, materials, etc.), constructiou
contingencies, design, and permitting costs. Additional analysis, modeling and design work will be
required to support the restoration opportunities and to develop detailed cost estimates. The following
estimates are for a conceptual level of planning and are more appropriate for identifying the relative cost
of opportunities among the various sites. These cost estimates should not be used for funding allocation
in a capital budget plan but can be used to estimate costs for a grant application. More details on the
assumptions used can be found in Tetra Tech (2008c).
Table 6-7. Stream Restoration Opportunity Conceptual Cost Estimates
Site Total Cost
Site SR-1 $813,194
Site SR-2 $750,000
Site SR-3 $1,422,500
Site SR-4 $1,272,500
Site SR-5 $1,247,917
Site SR-6 $521,510
Site SR-7 $1,355,208
Site SR-8 $624,500
Site SR-9 $952,000
Site SR-10 $428,000
Site SR-11 $618,750
Site SR-12 $575,000
The following actions will be required to successfully iinpleinent the recommended stream restoration
opportunities:
• Landowner outreach
• Project proponent identification (site-by-site basis)'
• Contact ACOE and other permitting agencies
• Coordinate with trails and infrastructure
• Coordinate with cultural resources priorities
• Preliminary design and cost estimate
• Secure needed permits
1 Project proponent is one or more entities that wish to conduct stream restoration on the project site. The proponent
inay be a local government or other agency, an NGO and/or a private sector entity that has mitigation needs.
(� r�rRw�
� -�� 6-30
Agua Hedionda Watershed Management Plan — Final August 2008
° ` • Secure funding sources
- • Secure stewardship organization
• Final planning and design
• Develop stewardship plan
• Implement projects
• Annual acquisition/restoration workshop
• Update prioritization tool; coordinate with sewer and stonn drain infrastructure programs
Implementation strategies to accomplish these actions are described in more detail in Section 7 and
Appendix H.
6.4 STORMWATER BMP RETROFIT PROJECTS
Most of the laiid that was developed within the Agua Hedionda watershed prior to the year 2001 was not
treated for stormwater runoff. Without stormwater controls, the increased rulioff can erode stream
channels, increase pollutant loadings, cause downstream flooding, and decrease groundwater recharge.
With Order 2001-01, the RWQCB began requiring widespread treatment of stormwater with BMPs to
meet MS4 permit requirements. The MS4 co-permittees within Agua Hedionda watershed are the County
of San Diego and the cities of Carlsbad, Vista, Oceanside, and San Marcos. The Order applies to
"priority projects", which includes essentially all projects in the Agua Hedionda watershed except for
those at the lowest densities. An estimated 70 percent of the development that occurred between the 2001
=f Order and the year 2007 received some level of stormwater treatment. Areas not receiving treatment
�` ._. were either not considered priority projects or received relatively ineffective treatments (e.g., drain inserts
used alone). The RWQCB subsequently updated the permit with additional treatment requirements (e.g.,
peak flow control and LID) in January 2007 by issuing Final Order No. R9-2007-0001 (2007 Order). The
vast majority of new development now requires treatment of stormwater according to the 2001 and 2007
Orders. Stonnwater retrofit projects are ineant to address areas that currently are not treated as a result of
the 2001 or 2007 Order.
Stormwater BMP retrofit opportunities identi�ed for Agua Hedionda WMP support goal #2, to protect,
restore and enhance habitat in the watershed, aud goal #3, to restore watershed functions, including
hydrology, water quality, and habitat, using a balanced approach that minimizes negative impacts. The
stormwater retrofit opportunities address both hydromodification impacts and water quality degradation.
The process for screening potential BMP retrofit sites and the resulting opportunities are described in the
following sections.
6.4.1 Screening Criteria
To address untreated development and restore water quality within the watershed, it is recommended that
a program of installing stonnwater BMP retrofits be initiated. There are more than 6,000 acres of
untreated development within the watershed excluding roads, parks, and very low and low density
residential developinent. Given limited resources to install BMPs to address ail of the untreated
development within the watershed, a screening process was employed to identify retrofit locations that
maximize effectiveness and feasibility. The screening process was implemented on two fronts. First,
publically-owned sites were selected within the priority subwatersheds, those with the highest existing
runoff and pollutant loading, identified in Section 2. Second, sites adjacent to the identified stream
restoration reaches were selected.
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'S��A 6 FiFa' Ca 9�/ �h_ 1iYT.i� 2a511J!'Ti��l
Tha �- uly 3,000 acres oCwil�raled parculs in �hc priority modcl subwatcrsheds Rrs� prc,- ntcd i
_.nenex , �
Section 4.1 2. Sincc it is �nlikcty that 6MPs c n bc installcd m trcat all of Hicsc pnrccls in tl�c ncar mrm,
publica0y-ownccl parccis within thesc subwatcrsheds havc bccn idm�tiflcd as highcst priority parccls lor
BMP placcmcnt (Figum 6-3). Thc�c arc about 34� a n 56 parccls of publically o ccl ]xnd w3tl�fn
Uiesc subwatcrshcds (Tablc 6-R). Approxi�nvtcty halt�arc ciry-owncd whilc thc rcmaining arc owned by
school dislnets, w�ter districts, and the Staie ofCaliCoiniz. Given the costs of Innd zequisition. Lhese
parccls rcprescnt soinv o{���c most tcasiUlc yotcn[ial sitcs m consvuct C3MP rctrotits.
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sliaded orange/y¢Ilow)
Q�w�wo�
Agua Hedionda Watershed Management P/an — Final August 2008
Table 6-8. Public-Owned Parcels Located within Priority Subwatersheds
Number of Total Parcel '
Owner Parcels ` Area (ac) Subwatershed Model ID(s) ;
Carlsbad Municipal Water District 2 55.9 1005, 1006, 1012, 1014, 1015
Carisbad Unified School District 18 86.4 1001, 1003, 1005
City of Carlsbad 1001, 1003-1010, 1013, 1027,
40 253.8 1028
City of Carlsbad Redevelopment Agency 3 4.8 1001
City of Oceanside 3 27.1 1009-1011
City of Vista 23 109.9 1015-1017
Regents of the University of California 5 76.6 1014-1015
State of California 3 93.3 999, 1002, 1004, 1005, 1028
Vista Irrigation District 3 2.3 1010, 1015-1017
Vista Unified School District 1 34.6 1015
Stormwater retrofit opporiunities have also been identi�ed along reaches where stream restoration
projects have been prioritized (Figure 6-8). Site maps for each site are provided in Appendix D.
Suppleinenting the stream restoration project with stonnwater retrofits will increase the benefits of the
�' Y project and provide additional hydraulic stability.
" The BMPs chosen for retrofits near stream restoration sites include extended dry detention (typically at
the outlets of the drainage areas), rainwater capture cisterns, penneable pavement, and vegetated swales
(used as either bioswales along road sides or as recessed medians). Appendix E illustrates the
recommended locations of these BMPs. Table 6-9 provides details regarding the drainage areas and
BMPs selected for each ret�ofit site. Note that the cuinulative percentage of area treated by BMPs
exceeds 100 percent for two of the retrofit sites. This occurs because some of the BMPs in those cases
treat only a portion of the drainage area, while the extended dry detention ponds treat the entire drainage
area. This BMP "treahnent train" is common practice where land area limits the use of larger, centralized
st�-uctures and when more stringent water quality goals are to be met. BMPs in series can provide
additional stormwater treatment benefits.
SW-4 was split into two subwatersheds — the larger residential area treated by the extended dry detention,
and the median swale to the south of the residential area. The drainage areas are not actuaily connected,
so they were evaluated separately.
� ��
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Agua Hedionda Watershed Management Plan — Fina!
j ,,.-
August 2008
Potential BMP retrofit opporiunities have been provided and may form the basis of a targeted program to
addressed untreated development in the watershed. For the targeted subwatersheds shown in Figure 6-6,
additional upland assessment and site selection will be necessary using publicaliy-owned land as a first
cut of potentiai BMP piacement sites. Once sites are selected, additional prioritization is conducted, and
funding sources are identified, additional data collection will be needed to support detailed cost estimates,
design, permittiug and construction. The retrofit sites located outside of the priority subwatersheds, but
adjacent to the stream restoration sites, may also be considered for implementation. Though concept
designs have been provided as an example of what might be installed on the sites, additional site data
�ti would need to be collected to suppoi�t more detailed design and cost estimation.
�
Steps included in the implementation process for BMP retrofits include:
• Landowner outreach
• Preliminary design and cost estimation
• Permitting
� Identify and secure funding
• Final planning, design aud costs
• Project construction.
6.5 MONITORING
Once WMP implementation has begun, a coordinated monitoring program for water quality, land use
change and treatment, restoration, and retrofits should be initiated. Specific tracking indicators identified
by the WPG can be integrated with existing inonitoring requirements under prograins such as the MS4
permit and the MHCP and MSCP programs. Periodically, implementation activities should be reviewed
along with water quality monitoring results to provide an understanding of the progress being achieved in
managing and restor-ing the Agua Hedionda watershed. As new information is gathered and effectiveness
is assessed, planned implementation actions may need to be modified under a process of adaptive
management.
In addition to ainbient water quality monitoring through the watershed, land treatinent tracking and
restoration monitoring are additional components needed as part of WMP implementation. Tracking is
(� rors,►�sa�
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Table 6-9. Drainage Area and BMP Retrofit Descriptions
Agua Hedionda Watershed Management Plan — Final August 2008
,> - recommended for future land use change and any associated BMP treatment. As noted in Section 3,
additional WIVII' tracking indicators include percent of development with LID controls and percent of
development with BMPs. This can be coordinated with SUSMP annual reports, SANDAG land use data
updates, and other tracking requirements.
6.5.1 Monitoring Indicators
The WPG has selected multiple water quality indicators for future tracking in the watershed (Table 6-10).
Indicators include sediment, nutrients, bacteria, metals and pesticides for tributaries to the Agua Hedionda
Lagoon. Lagoon indicators inciude TSS, turbidity, TP, TN, enterococcus, and fecal coliform. The
parameters chosen represent those tied to existing impairments and other constituents that are considered
elevated and warrant future tracking. Though not specifically identified as a tracking indicator by the
WPG, bioassessment will be important to track for restoration of aquatic habitat and biological
communities. The basis for parameter selection is discussed further below.
r.. .
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6.5.2 Existing Monitoring in the Watershed
Monitoring has been conducted by multiple organizations in the Agua Hedionda watershed. Each has
their own objectives. The Co-permittees have monitoring requirements for their Municipal NPDES
Pennit which has the following goals:
1. Assess compliance with 2007 Order
2. Measure and improve the effectiveness of the Co-peimittees' urban runoff management programs
3. Assess the chemical, physical, and biological impacts to receiving waters resulting from urban
runoff discharges
4. Characterize urban nuioff discharges
5. Identify sources of specific poilutants
6. Prioritize drainage and sub-drainage areas that need management actions
7. Detect aud eliminate illicit discharges aild illicit connections to the MS4
8. Assess the overall health of receivillg waters
Monitoring to comply with RWQCB Investigation Order No. R9-2006-076 (lagoon monitoring) to
support source assessments and linkage analyses for TMDL development for sediment (TSS and
turbidity) and bacterial constituents is ongoing and described further below. Other organizations have
'�.' Ti,R,►'f9C}I
� "� 6-35
Table 6-10. Monitoring Indicators for the Agua Hedionda Watershed
Agua Hedionda Watershed Management Plan — Final August 2008
- supplemented this monitaring including the San Elijo Lagoon Conservancy, the Watershed Stewards
Training for Citizens Monitoring, the Agua Hedionda Lagoon Foundation, and the Carisbad Watershed
Network (described further in Tetra Tech, 2007).
6.5.2.1 Receiving Waters and Urban Runoff Monitoring Program
Regular monitoring is required as part of the Receiving Waters Monitoring Program and Urban Runoff
Monitoring program described in the 2007 Order. Receiving waters monitoring is required at a mass
loading station, a temporary watershed assessment station, two bioassessment stations, in the lagoon, and
at selected coastal storm drains. The mass loading station is monitored twice during wet weather events
and twice during dry weather flow events during each year of required monitoring on Agua Hedionda
Creek at El Camiuo Real. The SELC supplements this with continuous flow monitoring.
In Agua Hedionda, mass loading inonitoring is required in permit years 1, 2, and 4. Additional
monitoring occurs as a temporary watershed assessment station monitoring in years 1 and 4.
Bioassessment monitoring is required in year 1 and 4 at two sites. Lagoon monitoring of chemistry,
toxicity, and benthic infauna is also required in either year 2 as part of the special program (Bight 2008)
or in all of the other four permit years.
In addition to toxicity tests, the parameters listed in Table 6-11 are required to be collected at the mass
loading and temporary watershed assessment stations.
,
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Agua Hedionda Watershed Management Plan — Final August 2008
��_, -
Table 6-11. Parameters Collected at the Mass Loading Station (based on 2007 Order)
Physical Parameters,
' Nutrients, Metals
;Hydrocarbons Pesticides (Total and Dissolved) ; Bacteria
TDS Diazinon Antimony Total Coliform
TSS Chlorpyrifos Arsenic Fecai Coliform
Turbidity Ambition Cadmium Enterococcus
Total Hardness Chromium
pH Copper
Specific Conductance Lead
Temperature Nickel
Dissolved Phosphorus Selenium
Nitrite and Nitrate Zinc
TKN
Ammonia
BOD (5-day)
COD
TOC and DOC
MBAS
Oil and Grease
Urban runoff monitoring has several additional monitoring components including MS4 outfalls, source
identification, and dry weather monitoriilg. Dry weather samples have been collected at 10 instream
stations and in over 50 storm drains in the Agua Hedionda watershed (these progralns are currently being
revised based on requirements of the 2007 Order). Co-permittees are also required to utilize monitoring
data and analysis from the Receiving Waters Monitoring Prograin to assess the effectiveness of their
programs.
6.5.2.2 TMDL Monitoring
The RWQCB issued Investigation Order No. R9-2006-076 to the dischargers to the creeks and lagoons in
San Diego County that are 303(d) listed for sediment, nutrients, TDS and bacteria. The Order requires
collection of data for the development of TMDLs under the Clean Water Act. The purpose of the
monitoring is to address the principal data needs required to develop watershed loading and lagoon water
quality models for the parameters of interest in the lagoons to develop TMDLs (City of Encinitas, 2007).
The monitorillg plau for Agua Hedionda Lagoon includes: (1) continuous monitoring of hydrodynainic
and cer-tain water quality parameters (salinity, temperature, flow or water level, and turbidityl), (2) wet
weather monitoring, and (3) dry weather monitoring. Mouitoring of hydrology and core chemical
parameters (saliliity, temperature, turbidity, and water-level and flow) will be measured via data sondes at
� At the mass emission station, turbidity is oniy collected during the dry weather index periods.
�
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Agua Hedionda Watershed Management P/an - Fina/ A�gust 2008
Lhe mass emission siee. witl�in cach segmcnt. and at [he oce2n ouxle�. Slor�n eva;nt sampling is planned £or
thc occan outict at Padtic Coast I Iighw-ay 6ndga, et H�c lvgoon ouHct at I-5, ai tlzc tributary, Hia n
lagoon scgmcnt, and t6c n � ioading station �Pigurc 6-9)_ Scdimoit sampling following ehe storm �cvcnt
nlsu p]anned lor �he maiu lagoon segmeuL Slonn evevts witb �ainCall rangine C�rom 02 inch to 1 i�d�
or grcatcr will bc targctcd. �ry wcaH�cr monirodng consists of scorm drains, cich n .. site.
occav inlct, and within lagoon sa�npling sites during kcy "indox" periods_ Sampling is�exPectod to bc
wviplcted Sn ihc fall of 2008.
Pollu�agraph s mplivg at [hv n - n tr3butary sitv- will o- - during two storm cvcn[s with cight
samplcs [aka� throughout the pollutagraph pn� stoe-m. Fivc sainplc�s will bc collcctcd Pcr stonn for
bucteria analysis. Paraviete�s i clude llow, T55, T�S, sed'u-r�ant particic vcc distribuGon, vnd bactena
({ cal coliforni, total col5{ ��n, and cntcrococcus).
6.5_2.3 CRAM Monitoring
Tho Calilumia Rupid Assessincnt Mcthod (GRAM7 i� a tcchniquc lor nwni�oring wGlarids. 1� c n bc
scd Por n u[oring c££or[s wfthfn e vatcrshcd contcxt m asscss c iulativc fnipac[s, a. ist with�locating
the best si�cs for restoration, and rqeorting on restoration p�njcct success_ It alw has the�F�o�cntial tu be an
ccllcnt tool co standardizc fl�c rcyo�2ing of site l�nyacts and c nzpcnsn[ory miGgation undcr thc 401 /404
pivg�ams_ und perhaps for TML7L pu��>oscs- In thc Fall of200�_ 23 C12AM n,-,cssment wmn perfonned
�hroughout thc watcrshed. 'I'hcsc uvcssmcnts w uGlfzcd to dcvdop tls r cndacfons Sn th3s
WMP. Puturc CRAM n �i�oring c i lill in gapv spatially ihrough ihc watcrshcd�nnd ovo'timc to
mtinitor im�ro��cmcnts or dcgradxtion a� spcciTc eitcy.
Omwwro�
Figure 6-9. Map of TMDL Monitoring Sites
Agua Hedionda Watershed Management Plan — Final August 2008
6.5.3 Future WMP Monitoring Recommendations
f
- All of the WMP indicators listed in Table 6-10 are collected at the mass loading station on Agua
Hedionda Creek (at El Camino Real) and in the lagoon, with a few exceptions. Total phosphorus and
DDT are not included in the list of parameters for the mass loading station sampling under the MS4
permit. Since DDT is persistent in the environment and no existing sources are expected, limited
monitoring in Buena Creek (e.g., twice a year) of this parameter is likely sufficient. Dissolved
phosphorus rather than total phosphorus is collected under the existing pennit requirements. The addition
of total phosphorus at the mass loading station should be considered given the present uncertainty in the
linkage and response of lagoon algal communities.
The specific parameters required for the lagoon monitoring were not identified in the 2007 Order.
Nutrients are not being collected as part of the TMDL monitoring since the lagoon is not impaired for
nutrients. Both nutrients and bacteria should be monitored in the lagoon on au annual basis. Lagoon
sampling should be conducted at the mid-channel station shown in Figure 6-9.
Wet weather monitoring extended to additionai sites within the watershed would provide a better
understanding of pollutant sources, areas requiring treatment, and watershed improvements. Additional
wet weather sites to consider that augment existing wet weather monitoring and provide additional spatial
understanding of storm-driven loading include:
1) Buena Creek near Dry Weather Station AH-13 (Figure 6-10)
2) Stormwater Outfalls not currently monitored in Subwatersheds 1001, 1003, and 1005
3) La Mirada Creek near Dry Weather Station AH-59 (Figure 6-10)
4) Calavera Creek at Lake Boulevard and Waverly Road
�,.�
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6-39
gua Hetlionda Wa[ershed Mar,
Ow „
.� � o„ s M�E�aS
s �
3ement P/an - Fina/
' �
—._ - ^ ��
c��.� �z ,- �`\o`
I� ' <. ,\ �"� ��_,e �°;�.
_....�, ..._ '"' .....- �----j
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r ,
C3�I/I-i
., o . . ,
,•,., _ •,_ � .. � rE_..,.E�..
Figure 6-10. Monitoring Stations in tFe Agua Hedionda Waters6etl
Prog�rss in mcelinb' ����=TMCJL objcctivcs aod w address [hc r unpai»ne-uts w-fll rcquirc
nitoring in tls f'uturc in thc la�,00n and i[s tribucarics_ This n nito�ing plan will likcty not bc
dcvNoped until aftcr thc'I'MOL is dcvdopcd. Thcin�plcmcnta�ion inonitoring should bc coordinatad
wilh inunilorine nncdcd to support �hc goals and objcctivas o£t1�3s WMP.
Bioasscsvncni n �itonng, incLuding uqua�ic habi[at, c�uld bc improvcd by addin� othcr sitcs bcyond the
[wo rcqu �cd i ndcr thc pc iit. i-labitat w. nportant comV���cn[ ofthc goals and obJ�ctives ofthc
WMP. As � �ch. addiGunal sitcs arc wanant 1.� In addiGoo to Al1C-ECR and AII-MR, r mcndcd
si[cs inc]udc�AliS02 and n rcprescntativc sltc on I3ucne G�cck, co bc dctcrinincd during plan���
implcnicntation.
Bsssed on svong in[crest exprcssed by the WPG, wn recommand that CaliLomia Rap9d Asscsvnant
McHiod (CRAM) data bc periodfcnlly collcctcd and a . scd {�- w,ctland arcas oFtM1c waccrshcd.
Monitoring res�dts fi-om CRAM asscssmcnts shoWA bs compared to result� repurted io Tetra Tech (200�)
m avc.ss unprovamc��t or dc�radntioo in w-atland funcGons.
In addition m thc ainl icnt n nitorin� nccds dcso�ihcd in thc prcccding scctions, pro— and post-
constivction mouitorine ofany projccte implemcuted in association wiih the WMP should be conductcd
.. - . allow. This would ineludc strcam resturuGon and 6MP rctro£t projccts. Such n nieoring
enn demonsvato re�l benofiis of these V�"3etices and provide pronrammatic fcedback C>r reporting. thc
M54 pcnnit.
TFc Following actions will bc rcqu�rcd to succcssRilly implcmrnc thc recommencied monitoring:
. I.ong te�.rm strcam and lagoon monitoring P�'��ra�n (supplemcntin�, cuncni nwnitoring by Co_
pc�inittccs)
Q�w�wo�
Agua Hedionda Watershed Management Plan — Final August 2008
• Collect and assess physical, chemical, and biological data from multiple programs
�-- • Periodically report on monitoring results
• Long-term wetlands monitoring (CRAM)
• Inspections and maintenance of sanitary sewer systems
• Check lines for leaks, illicit connections, and overflows (included in the CA Sanitary Sewer
Overflows Waste Discharge Requirements (SSO WDRs))
• Monitor effectiveness/efficacy of BMP demonstration projects
• Inspections and maintenance of storm drainage systems
• Increase efforts to clear and maintain storm drains and drainageways to remove deposited
inaterials. (Included in "Regional Channel Maintenance" program.) Note: Any disturbance to
uatural channels should be minimized.
• Construction site inspection and enforcement action
• Conduct onsite inspections and take enforcement actions, as needed, during construction
(included in the 2007 Order)
• Stormwater BMP inspection and euforcement
• Staff inspect onsite stormwater inanagement systems and take enforcement action, as needed, on
failing systems (included in the 2007 Order)
• Track key Watershed Management Plan Indicators.
�� Implementation strategies to accomplish these actions are described in more detail in Section 7 and
° �� Appendix H.
6.6 CITIZEN STEWARDSHIP/PUB�IC OUTREACH
6.6.1 Collaborative Watershed Council
Stewardship and management of the Agua Hedionda watershed depends on the collective efforts of
citizens, businesses, non-governmental organizations (NGOs) and governmental agencies. A Watershed
Council is recommended as a way to establish and support a strong partnership among those
organizations which have significant authority or resources for managing the watershed. It is also
inteiided to ensure meaningful pubiic participation in the decision-making. A Watershed Coordinator
should be hired to staff the Council.
Watershed management should be adaptive—a living process that responds to changing conditions,
needs, and inforxnation. Instituting a Watershed Council establishes an approach that can adapt to
changing needs and will allow current and future issues to be addressed in ways that are both
environmentally sound and fiscally responsible. It is an approach in which all stakeholders pool and
coordinate their teclulical and finaiicial resources to achieve the watershed inanageinent goals.
This Plan recommends that the Council include multipie coordinating forums to support stakeholder
involvement, providing an opportunity for everyone to participate to the levei they want to contribute and
providing a known place to "plug in."
Watershed Council. This group should comprise lead staff and officials from partners that have
significant authority and/or resources to manage the Agua Hedionda watershed. The purpose of the
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Agua Hedionda Watershed Management Plan — Final August 2008
Council is to coordinate on policy, funding, and resource allocation issues, to provide sustained
f leadership, to ensure that the partnership is strong, and that the management plan is updated as needed.
It is highiy recommended that one elected of�cial from each local government jurisdiction be appointed
to the Council. This is vital for successful implementation because of their power to direct staff, approve
budgets and/or sponsor grant efforts for management ineasures. In addition, this group of stakeholders is
responsibie for the infrastructure in the watershed and represents the regulated community, generally held
responsibie for compliance with water quality regulations, including future TMDL implementation.
Technical Advisory Committee. This Committee should include staff representatives from
governmental agencies and select non-governmental organizations with expertise on water resource and
land planning issues in the watershed. The purpose of the Committee is to help carry out the activities of
the Watershed Management Plan and to report recommendations to the Council.
Watershed Partners. This group is comprised of interested citizens, NGOs, local land owners, media
and businesses. It also includes responsible parties that are regulated by other agencies, such as the local
Co-permittees who are responsible for NPDES Pennit and TMDL compliance. The Watershed Partners
would have a key role in implementing the WMP. It is envisioned that the Watershed Plaiming Group
members, responsible for guiding the developinent of the WMP, would participate in this group.
Funding Committee. The purpose of the Funding Coinmittee is to provide and seek funding
opportunities to finance implementation of the WMP. The Funding Committee would include local
governments, state and federal agencies, and private foundations, developers or corporations. These
stakeholders can provide direct funding, grants and loans. The partners need to be infonned continuously
about the cost of impleinenting the WIVIP projects and the benefits provided to the community. The
funding partners on the Committee would make recommendations to the Council on funding
opportunities and priorities.
As a first step for the Council, it is recommended that a grant be secured to hire a Watershed Coordinator
who would support the work of the CounciL In the future, the work and staff of the Council could be
funded through Council partners, grants, reallocation of local goveniment fees, etc.
6.6.2 Education of Local Boards to Gain Support for Watershed
Management
Because it is recommended that the local boards (City Council, City Planning Coirunissions, Agency
Boards, and County Supervisors) provide priinary support and possible funding for the WMP projects,
their support is criticai. The Watershed Council should meet with these boards during their regularly
scheduled meetings on an annual basis to update them on the needs, bene�ts and progress of the WIvIP
implementation. Table 6-12 provides a guideline %r the content and goals of these ineetings.
(�j r�rRwr�
t=a 6-42
Agua Hedionda Watershed Management Plan — Fina! Augusf 2008
��.
�:
Table 6-12. Content and Goals for Educating Local Boards
Meeting ;
Number Content Goal
1 Introduction of the WMP, goals & objectives, Adoption of the WMP
summary of recommendations, and plans for
implementation. This should include how the Support for the WMP
WMP meets current board goals and relates to Participation of Board Member/s on Watershed
the board's existing programs. Council and direction for staff participation
Commitment to include WMP explicitly in future
board goals
2 Overview of the WMP (refresher), summary of Continued support for the WMP
actions to date, identification of barriers to
implementation, request for assistance to Understanding of how the WMP helps meet
overcome barriers (if appropriate), and request general board goals
for continued support. Commitment to include the WMP explicitly in future
board goals
Annually Same as #2. Same as #2.
Present new finding and information about Help adapt the Watershed Plan as needed.
watershed conditions and management
opportunities.
6.6.3 Development of Citizen Education Materials
Education of the general public is an important first step in order to effect changes in habits that impact
the watershed. It is important to educate the public about the direct benefit of a healthy watershed to their
quality of life. The public must understand what a healthy watershed looks like and how they can
contribute to positive watershed health. Educational material should include messages that support the
many overlapping programs that work to improve the watershed; for example, habitat protection and
management (MHCP/MSCP), water quality (stormwater NPDES Pennit), water conservation (State
Model Water Conservation Ordinauce), reduction of impervious surfaces (Starmwater NPDES Permit
LID aud Hydromodification). These materials should strive to be distributed in English and Spanish.
Educationai materials can include:
• Brochures
• Agency bili inserts (brief flyers in water bills)
• Write-ups in local city, agency, NGO and appropriate groups' newsletters and websites.
Specifically these would include:
o Local jurisdiction — Cities of Carlsbad, Oceanside, San Marcos, and Vista, the County of
San Diego
o Local Water Agencies — Carisbad Municipai Water District, City of Oceanside Water
Utilities Department, Vallecitos Water District, Vista Irrigation District
o Locai Sewer Agencies — the Buena Sanitation District (Vista), City of Carlsbad, City of
Oceanside Water Utilities Department, City of Vista Sa�itation District, and Vallecitos Water
District
o Local NGOs — Agua Hedionda Lagoon Foundation, Preserve Calavera, Friends of Hedionda
Creek, Carlsbad Watershed Network
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Agua Hedionda Watershed Management Plan — Finai August 2008
o Appropriate Groups — local Homeowner Associations, Chambers of Commerce, primary
' businesses (Poseidon, Cabrillo Power Plant, YMCA, Hubbs SeaWorld, etc.)
• Press releases to local media, including the North County Times, Union Tribune (North
County section and Spanish edition, Enlace), and Coast News
• Training for watershed monitoring
6.6.4 �ID Workshops and Training
Low Impact Development has been identified in the WMP as a strong tool to mitigate impacts from future
development and support non-degradation of water quality and watershed health. To promote LID use in
its most optiinal form for the watershed, LID workshops and training sessions are recommended. The
purpose of these workshops and training sessions is to increase implementation of the most effective LID
techniques throughout the watershed. Workshops should be held for jurisdictional staff, private sector
developers and engineers, and the interested general public. There are good opportunities to collabarate
on the workshops with other organizations, including local jurisdictions, San Diego Coastkeeper and the
Building Industry Association (BIA). The workshops should include general LID education, however
they should focus on local knowledge obtained from the modeling effort in this WMP (see Section 6.1
and Appendix �. It is recommended that workshops and training for municipal staff be performed by
other professionals or professional organizations. Education for engineers and developers inight best be
received from professionals within local jurisdictions who will be approving developer plans, whereas
workshops for the general public could be conducted by local jurisdictions and by NGOs.
6.6.5 Annual Awards Program
An annual awards program is recommended to encourage and recognize local efforts toward watershed
protection. This program should be coordinated through the Watershed Council. To be transparent and
objective, the program should have specific objectives, guidelines, nomination criteria and prioritization
processes. It is recommended that these guidelines be formally drawn up and voted on by the Watershed
Council and posted on the webpage. Awards should be considered for individuals, public officials,
developers, businesses, and NGOs. Presentation of the awards should include a press release to maxiinize
publicity and the educational value of the event.
6.6.6 Annual Progress Workshops
A number of watershed actions are being recommended that will involve numerous agencies and groups.
To keep track of "who's doing what" in the watershed and progress made on WIvIP impleinentation, it is
recommended that Watershed Partners have annual progress workshops. This would also be a forum to
share lessons learned on LID techniques, successful BMP retrofits, etc. These workshops could be held
in conjunction with the arulual acquisition/restoration workshop.
6.6.7 Management Partnerships
Many partnership opportunities exist within the watershed to leverage programs towards project
implementation. These partnerships should not be underestilnated as a means to implelnent the WMP. A
partial list of key opportunities is presented in Table 6-13.
(� r.risw�
� --� 6-44
Agua Hedionda Watershed Management Plan — Final August 2008
F,
Table 6-13. WMP Partnership Opportunities
' Potential Partnering
Partnership Organization Opportunity Potential Project for Opportunity
Local, State & Federal Agencies Funding Land acquisition, restoration projects
Carisbad Watershed Co-permittees Collaboration Educational materials, workshops,
meetings
Utility Agencies Collaboration, Matching Restoration for infrastructure construction
Funds and maintenance, educational material
development and distribution
Private Developers Funding, Matching Funds Acquisition and/or restoration as mitigation
for development
NGOs Collaboration Educational material and events, project
prioritization, awards program
Businesses Collaboration Educational material distribution, awards
program, workshops
6.6.8 Data/lnformation Management Via Website
Information sharing is iinportant to inaximize collaboration and keep stakeholders informed. As data is
collected in the watershed by various stakeholders, it is helpful to integrate that data and use it for
decision making, whether it be for management measure selections, effectiveness evaluations, or project
�,.
prioritization. It is recoirunended that a website be the best avenue for information sharing. The website
..:: :,:
should maintain program information including an overview of the WMP, announcements, events
caleudar, meeting archives, educational material ongoing projects, and links to other related programs. It
should be maintained on a regular basis which will include staff time to prepare updates and funding to
support website hosting.
Implementation strategies to accomplish citizen stewardship/public outreach actions are described iii
more detail in Section 7 and Appendix H.
6.7 FUNDING AND SUSTAINED SUPPORT
Securing and maintaining stable and diverse funding for WMP will be challengiug and an ongoiilg action.
A wide range of funding options is availabie for watershed actions and having a variety funding sources
will help avoid interruptions in implementation and reliance on a single entity far support (EPA, 2005).
This section discusses a variety of funding options most applicable to the watershed; other means do exist
for funding and sustaining support for watershed management, and those options should be expiored as
well.
6.7.1 Grant Programs
The California voters have been generous in past ten years supportillg a range of water related bond
programs. In addition, there is wide support for coinmunity-based watershed restoration programs.
Water quality related actions that are well supported include stormwater quality best management
practices (BMPs) and low impact development (LID). Many of these programs are oriented towards
"brick and mortar" implementation; therefore having a Plan with specific projects identified sets the Agua
Hedionda WMP up well for iinplementation.
(� r�,s,►�
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Agua Hedionda Watershed Management Plan — Final August 2008
A wide range of grant programs are available so that it is important to match the appropriate project with
the grant program. Some of the primary grant programs that are appropriate for the Agua Hedionda
management measures include small grant programs for education and outreach programs and
development and support of the Watershed Council and Watershed Coordinator, and larger grant
programs for implementation projects, such as acquisition and restoration. Appendix H provides a list of
several current grant programs, who administers the grant, the type of projects eligible for the project and
the range of available funds for each grant.
Almost all grants require some amount of matching funds be contributed by the recipient of the funds.
Grant match provides granting organizations the assurance that the grant recipient is dedicated to the
project and willing to put in their own effort or fivances. Matching funds are generally in the range of 10
to 20 percent. In rare cases no matching funds are required and in some grant programs up to 50 to 75
percent matching is required. Matching funds generally are in the form of in-kind labor, up-front funding
of project design or environmental clearance, or pre-project monitoring used to define the project need.
Many funding agencies have restrictions regarding where the matching funds can be derived, for instance
grants from the State generally disallow matching funds to be derived from other State funds or programs.
Once the project has been aligned to a grant program, the grant scope must be outlined. Often grant
programs require a two-step process where a conceptual scope is submitted and if approved the grant
applicant will be asked back for a full proposal that is more detailed. The level of detail of the scope
depends on the grant requirements; however, it is always helpful to have the project well scoped out prior
to any grant application so that the technical feasibility, project budget and schedule are well uuderstood.
The projects outlined in this WMP are generally in a conceptual stage and require additional effort to
develop the scope and budget for a grant application. During the scoping process project partners should
be identified who wiil provide support for the project either financially or technically.
�' In the Agua Hedionda watershed there are many ongoing projects that can also be leveraged as matching
�� ,: funds for the recommended management measures. These include partnering with ongoing educational
programs by the various NGOs in the watershed, jurisdictions (particularly the Carlsbad Watershed Urban
Runoff Manageinent Program), and private organizations who perform enviromnental education to
support their business. Another source of matching funds that is promising in the Agua Hedionda
Watershed is partnering with other implementation projects performed by jurisdictions, agencies or
private ventures. In the near future it is likely that the jurisdictions withiu the watershed will be
implementing projects associated with improvements and maintenance to their sewer, water and storm
drain infrastructure. These projects may be implemented in conjunction with watershed projects for
matching funds or the implementation oi the infrastructure project may require initigation that can be
used to leverage a larger graut project. In addition, local development projects will be required to
mitigate impacts. All of these types of projects create opportunities for partnerships on large mitigation
projects and for matching funds.
It is important to contact appropriate agencies as early as possible to gain support for the project. The
implementation projects recoirunended in this WMP will require ageucy environmental clearance that in
some cases may require substantial effort. Agencies are generally willing to meet with project proponents
to discuss their projects and provide assistance and direction regarding the approval process. The various
agencies and environmental clearances that are likely to be required for project implementation are
discussed in Appendix A, Summary of Key Federal, State, and Local Regulations Applicable to the
Watershed. In most cases, the projects support the goais of the agencies so that they can be helpful
partners. Grant ageilcies look favorabiy on the involvemeut of a variety of agencies because it shows a
higher level of support and more likely rate of project success.
Finally, preparing the grant application can require a significant effort. to make the application as
competitive as possibie, it is important to l�ow the project and applicant eligibility requireinents, project
types to be funded and program goals. The applicant should discuss the project with the granting agency
Q rrrw��
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Agua Hedionda Watershed Management Plan — Final August 2008
in advance to better understand the funding probability of each project. Often the granting agency wili
' have a public meeting to discuss the grant program well in advance of sending out a request for proposals.
Many grant programs will have a list serve that can be joined to receive automated information about
upcoming programs.
6.7.2 Coordination with Agencies
Several agencies have ongoing programs that could fund projects within the watershed. Often agencies
are interested in land acquisition to develop preserves or protect natural habitat. State and federal funds
or programs are established for preservation efforts, particularly where there are endangered species, or
sensitive habitat. The State of Califonlia Wildlife Conservation Board Grant program funds restoration
and enhancement of wildlife habitat, development of public access facilities for wildlife oriented uses and
protection of habitat through fee acquisitions and conservation easements. The Partners for Fish and
Wildlife Program provides technical support and funding for on-the-ground wetland restoration projects
on private land. The National Fish and Wildlife Foundation also provide grants for projects that sustain,
restore and enhance the nation's fish, wildlife, plants, and their habitats through their Keystone Initiative
Grants and Special Grant Programs.
The State and federai wildlife agencies also sign off on mitigation plans and often a project has a need to
mitigate offsite which requires au acquisition or restoration project. Caltrans also is involved in
acquisition and restoration projects for road project mitigation and is another potential partner. The
regional planning agency, San Diego Association of Governments (SANDAG), will soon be allocating
acquisition funds from the 1/2 cent Transnet sales tax measure. In addition, there may be opportunities
with local jurisdictions to coordinate on projects related to their MHCP/MSCP efforts or as mitigation for
development projects. Universities may also be interested in developing or expanding preservation or
� '� restoration programs.
It is recommended that these agencies be contacted on a regular basis to discuss the WMP recommended
projects and request that they consider the project lists when developing their agency goals and priorities.
These agencies can also be helpful in identifying funding opportunities that may arise that are appropriate
for the WMP projects. Another important aspect of coordinating with agencies is to keep them informed
of locally available projects that can be used for mitigation and stress the need to impiement local projects
to offset local iinpacts.
6.7.3 Mitigation Programs
As development within the watershed grows and infrastructure projects (freeways, roads, pipeliues, etc.)
are planned there will need to mitigate their impacts. Most of the acquisition and restoration projects
outlined in the WMP are suitabie projects for mitigation. Furthermore, since most agencies request that
mitigation be implemented near to the area of the impact and prefer areas where a detailed analysis and
comprehensive process has been conducted for mitigation site identification, mitigation compensation is a
good option for funding implementation of the projects recommended herein.
The challenge is inatching mitigation needs to projects. Mitigation requireinents are generally required at
a specifie size, and only in rare cases will that size match directly with a project outlined in this WMP.
However, with some creativity this can be overcome. Options include developing mitigation banks, pre-
approved mitigation areas (PAMA), or an in-lieu fee program. These programs are designed to pool
resources from a range of mitigation requirements to create a larger project that is more likely to have a
greater benefit to the watershed. These programs are a tremendous benefit to project proponents in need
of mitigation and can result in significantly inore bene�t to the watershed then a group of smaller
mitigation projects scattered throughout the watershed. The other benefit to this approach is collectively
obtaining permits for the mitigation and long-tenn management of the final project. Mitigation Banks can
a��
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Agua Hedionda Watershed Management Plan — Final August 2008
- be established by a city, county or land management organization who will perform the upfront project
� design and permitting and then sell-off credits or acres to project proponents in need of mitigation. One
example in the watershed is the 180-acre Carlsbad Highlands Mitigation Bank created by the which is
now sold out and the properiy is being managed by CDFG as part of the Carlsbad Highlands Ecological
Reserve (TAIC, 2008).
6.7.4 Watershed Council Support
Having a long-term organizatiou such as a Watershed Council to oversee and sustain the implementation
of the WMP will be one of the keys to its success. Keys to the success for the Watershed Council is
having a Watershed Coordinator who will manage and support the organization, coordinate activities and
obtain sustained funding for management implementation.
Funding and hiring a Watershed Coordinator in the near term (i.e., six months) is essential. The WMP,
which has well documented watershed needs and recommendations, provides a strong basis and
momentum for establishing a Watershed Coordinator position and establishiug a Watershed Council. This
momentum should be capitalized on quickly.
Funding for a Watershed Coordinator can be obtained from a variety of sources. Agencies, such as the
Department of Conservation, are recognizing the importance of Watershed Councils and Watershed
Coordinators and have a grant program established solely for that purpose. Other grant agencies are also
recognizing this need and are open to funding such a position either outright or as a part of a larger
project. Again, with some creativity, the watershed coordinator position can be funded from a variety of
sources; however, a more sustained form of funding is desirable in order to inaintain a long-term
connection to the watershed and the programs outlined herein.
�., w
More diverse fonns of support include additional types of grants, local agencies and/or jurisdictions,
NGOs and the business community. For example, each project that is funded in the watershed can also
have a coinponent included in the scope to support the Watershed Council and Watershed Coordinator.
Most grants from the State of California require that public meeting be held and technical advisory
committees or watershed planning groups be established to oversee the project. This can be used as an
opportunity to support the Watershed Coordinator. Appendix H provides a list of funding opportunities
in the form of grants to support a watershed coordinator. Because of their role i11 overseeing
development, local jurisdictions will be key participants in the Watershed Council. As such, they could
also be considered as potential funding sources far the Watershed Coordinator and Watershed Council.
6.7.5 Implementation
The foilowing actions will be required to successfuliy impleinent the efforts described above:
• Grant Prograins
o Identify target grant programs
o Match projects to grallt programs
o Scope projects, identify partnerships and matching funds
o Contact appropriate agencies and discuss projects
o Prepare grant applications
• Coordination with Agencies
o Identify target agencies and funding opportunities through agency programs
o Meet quarterly with appropriate agencies to discuss priorities and opportunities
(� r�rRnTrai
� -�� 6-48
Agua Hedionda Watershed Management Plan — Final August 2008
o Coordinate with Universities
` -- • Mitigation Programs
o Meet with jurisdictions and agencies to discuss mitigation banks and iu-lieu fee programs'
o Align projects with mitigation banks and in-lieu fee programs
o Obtain agency support for mitigation banks and in-lieu fee programs
o Outreach to development community
• Watershed Council Support (Watershed Coordinator Support)
o Prepare scope for watershed and staffing needs ($)
o Obtain local support from agencies, jurisdictions, NGOs and the business community
o Identify grant/funding opporiunities and pursue with grant proposals
o Redirection of City fees
Implementation strategies to accomplish key actions are described in more detail in Section 7.
6.8 RECOMMENDED FOCUS AREAS FOR MANAGEMENT
The selection of individual opportunities in the previous sections was based on a watershed-wide review
of management needs and opportunities. Each priority opportunity represents a location where a
significant management need exists. Several of the stream restoration opportunities address bank
undercutting that is endangering mature riparian trees. The top ranking land acquisition opportunities
represent parcels where large tracts of undisturbed natural area are unprotected and where new
development would have the greatest impact on water quality and habitat relative to other unprotected
parcels. Drawing from individual priorities, the combined benefits of multiple management types was
considered in selecting the focus areas. Although some individual prior•itizations considered the
relationship among types of opportunities (e.g., the restoration opportunity metric for the acquisition and
restoration opportunities), the purpose of the focus areas was to select several comprehensive suites of
opportunities that would be implemented in concert to achieve a greater fuuctional benefit.
Tetra Tech based the selection of focus areas on the location of inanageinent opportunities, the WPG's
goals aud objectives, and general trends in modeling and monitoring data. Each focus area represents a
portion of the watershed where a significant management need exists and where a number of
opportunities would complement each other. The portions of the watershed not selected as focus areas
contained fewer complementary management opportunities and/or presented constraints to management.
Most notably, Tetra Tech considered the Calavera Creek drainage area as a potential %cus area but
concluded that the streain conditions should be evaluated after the Lake Calavera dam is repaired2 and
before a comprehensive restoration effort is plalmed within this drainage. In addition to this factor, the
upper portion of the Calavera Creek drainage area did liot present as many complementary mauagement
opporiunities as the selected focus areas. In general, the selected focus areas presented more promising
habitat preservation aild restoration opportunities than other portions of the watershed.
� Development of a mitigation bank or in-lieu fee program requires careful planning and close coordination between
project proponents, local jurisdictions, and the wildlife agencies to meet the specific conditions of mitigation.
2 The dam is expected to be repaired and site construction completed soon after the WMP is finalized.
(� �rRw�
� --� 6-49
Agua Hedionda Watershed Management Plan — Final August 2008
The selection of focus areas does not imply that management should only be focused in these selected
: areas. Tetra Tech recoinxnends that funding be focused in these portions of the watershed in the near
term, and that management opportunities within the focus areas should be implemented in concert where
possible. The priority lists and decision-making tools provided with the plan may lead implementers to
select promising management opportunities outside the focus areas because an opportunity presents itself.
With sufficient funding and other support, it may be possible to implement the focus area management at
the same time as other priority management actions throughout the watershed.
Where possible, upstream management within focus areas should be accomplished first. During
implemeutation, trade-offs will need to be considered between readily available opportunities and those
that provide the greatest functional benefit. For example, several extended diy detention (EDD)
opportunities may exist that, if implemented, would protect a stream restoration opportunity from damage
during storm events. The stream restoration opportunity may have funding available first, while EDD
facilities are still in the conceptual design phase and are several years away from funding. Impiementers
will need to consider the risk of implementing the stream restoration site prior to the upstreain protection
versus the delayed benefits if the restoration is postponed. In this situation, implementers may decide to
construct the stream restoration first if there is a low risk of damage, and then construct the EDD facilities
as soon as possible following the restoration.
Tetra Tech recorrunends three focus areas for watershed management:
• Headwaters Focus Area: The headwaters of Agua Hedionda and Buena creeks, including
subwatersheds 1019, 1020, 1021, 1022, and 1024.
• Mainstein Focus Area: The mainstem of Agua Hedionda Creek along SR-02, SR-03 and SR-04
and land draining to the creek that has a significant impact on this reach, including subwatersheds
1013, 1014, 1015, 1016, and 1017.
• Lagoon Focus Area: Agua Hedionda Lagoon and subwatersheds draining directly to the lagoon,
f� including 1000, 1002, and 1004 as well as land withiii adjacent subwatersheds directly impacting
the lagoon.
The focus areas directly address the WPG's goals and objectives. They most strongly address Goals #2
and #3 by representing where the greatest iinprovement in habitat and water quality can be achieved. The
focus areas also address Goal #1 by identifying management opportunities that would help protect
downstream efforts and ensure management success overall. Efforts through goals #4 (regulatory
compliance support) and #5 (outreach, education, and stewardship) can also be achieved by concentratiug
management in the focus areas. Emphasis on regulatory compliance and citizen outreach with these focus
areas will help ensure that the greatest functional benefits are achieved. The following bulleted lists
provide the rationale for selecting these focus areas, and specific management opportunities are
recoinmended within each focus area.
Headwaters Focus Area
Location: The headwaters of Agua Hedionda and Buena Creeks, including subwatersheds 1019, 1020,
1021, 1022, and 1024 (Figure 6-11).
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Rationale for Selection:
• Is the least developed portion of the watershed and contains large opportunities for land
preservation (acquisition)
• Has high potential for future development
• Has high potential for future pollutant loading and stream erosion risk
• Buena Creek Headwaters experiences high nitrate loading during extended dry periods. A
potential source may be nutrient-laden irrigation return flow from lawns.
• Agua Hedionda Headwaters have been designated as a stakeholder priority for land acquisition
and preservation and contain the majority of high priority land acquisition opportunities based on
the WMP's overall prioritization criteria.
• Buena Creek Headwaters contain a large number of inediuin priority acquisition opportunities
based on the WMP's overall prioritization criteria.
Complementary Management Actions:
• New Development Site Management: General attention to compliance with new standards and
application of innovative practices, including LID, and consideration of enhanced management.
Recommend that jurisdictions focus on minimizing nutrient load from new lawns and other
landscaping.
• Preservation:
o Primary focus on preserving top ranking, high priority opportunities: LA-0l, LA-02, LA-03,
� LA-04, LA-06, LA-07, LA-01, LA-11, LA-12, LA-18, LA-35, LA-41, LA-42, LA-43, LA-
� 44, LA-46, LA-48, LA-50, LA-52, LA-53, LA-55, LA-57, and LA-58.
o Secondary focus on preserving large tracts and remaining riparian areas among the medium
priority opportunities, including any stakeholder priorities that are not listed above.
• Buffer Restoration:
o Primary focus on restoring top ranking, high priority opportunities: BR-03, BR-04, BR-O5,
BR-06, BR07, BR-08, BR-10, BR-11, BR-12, BR-13, BR-14, and BR-22.
o Secondary focus on restoring medium priority opportunities. No stakeholder priorities have
been identified, but stakeholder input should be considered when selecting projects for
iinplementation.
• Wetlands Restoration: Wetlands restoration opportunities are limited in this focus area to
inediuin and low priority opportunities.
o Primary focus on the highest scoring opportunities: WR-62, WR-64, WR-65, and WR-66.
o No secondary focus due to limited opportunity.
• Stream Restoration: Primary focus on SR-06 on Buena Creek.
• BMP Retrofits: BMP retrofits should not be a primary focus, but may be a secondary focus
where opportunities are available for EDD and downspout discomiection.
• Monitoring:
o Pre- and post-construction inonitoring of stream restoration sites.
- o Land treatment tracking far new development.
a��
6-52
Agua Hedionda Watershed Management Plan — Final August 2008
• Citizen Stewardship:
o Outreach to landowners throughout focus area on the benefits of controlling invasive species
and maintaining natural vegetation on their properry.
o Promotion of enhanced new development site management among stormwater regulators and
developers.
Mainstem Focus Area
Location: The mainstem of Agua Hedionda Creek along SR-02, SR-03 and SR-04 and land draining to
the creek that has a significant impact on this reach, including subwatersheds 1013, 1014, 1015, 1016, and
1017 (Figure 6-12).
Rationale for Selection:
• Contains the largest, contiguous stream restoration need and opportunity within the watershed,
which addresses endangered mature trees and channel erosion.
• Includes two subwatersheds targeted for BMP retrofits due to high pollutant loading and a large
number of untreated parcels. The loading from these subwatersheds is expected to have an
influence on water quality within the stream restoration opportunities and contribute to hydraulic
stability.
• Stream, buffer, and wetlands restoration opportunities are adjacent to protected natural areas and
public recreational areas.
• Has high potential for complementary habitat restoration, preservation, and flood retention
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Complementary Management Actions:
• New Development Site Management: General attention to coinpliance with new standards and
application of innovative practices, including LID, and consideration of enhanced management.
Recommend that jurisdictions focus on addressing hydromodification to protect channel stability.
Most of the focus area is developed, but some potential for future development exists.
• Preservation: Land acquisition opportunities are limited in this focus area to medium and low
priority opportunities.
o Primary focus on preserving riparian portions of inedium priority land acquisition
opportunities to maintain habitat contiguity and protection of restored channels, including the
highest scoring opportunities (including LA-08, LA-20, LA-OS) and the nearest opportunities
upstream from SR-02 (including LA-126 aud LA-348).
o Secondary focus on preserviug stakeholder priorities not listed above and additional upland
areas.
• Buffer Restoration:
o Primary focus on restoring top ranking, high priority opportunities: BR-01, BR-02, BR-16,
BR-19, BR-21, BR-30, BR-31, BR-38, BR-39, BR-40, and BR-46. Some overlap occurs
with wetlands restoratioil opportunities.
o Secondary focus on restoring medium priority opportunities. No stakeholder priorities have
been identified, but stakeholder input should be considered when selecting projects for
implementation.
� ��
6-53
Agua Hedionda Watershed Management Plan — Final
August 2008
• Wetlands Restoration:
o Primary focus on the top ranking, high priority opportunities that are contiguous and present a
significant flood retention opportunity: WR-01, WR-02, WR-04, WR-O5, WR-08, WR-09,
WR-10, WR-11, and WR-20.
o Secondary focus on other top ranking, high priority opportunities: WR-07, WR-13, WR-14,
and WR-19.
• Streain Restoration:
o Primary focus on opportunities SR-02, SR-03, and SR-04.
o Secondary focus on opportunity SR-0l.
• BMP Retrofits:
o Primary focus on EDD upstream of SR-03 and SR-04. For maximum benefit, EDD retrofits
should be implemented throughout the focus area in a decentralized manner so that flow
control mimics natural hydrology. SW-01 BMPs are provided as example opportunities that
would complement stream restaration.
o For subwatersheds 1015 and 1017, primary focus on retrofits that reduce pollutant loading.
• Monitoring:
o Pre- and post-construction inonitoring of restoration and retrofit sites.
o Land treatineut tracking for new development.
• Citizen Stewardship: Include outreach to property owners along creek regarding maintenance of
riparian habitat, eontrol of invasive species, miniinization of erosion, and other practices. Smali,
low-scoring acquisition and restoration opportunities can be used to target outreach.
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Lagoon Focus Area
Auqust 2008
Location: Agua Hedionda Lagoon and subwatersheds draining directly to the lagoon, including 1000,
1002, and 1004, as well as land within adjacent subwatersheds directly impacting the lagoon (Figure 6-
13).
Rationale for Selection:
• Represents a large portion of the remaining wetland habitat in the watershed.
• Lagoon habitat is listed as a priority under WPG goals and objectives.
• Includes subwatersheds targeted for BMP retrofits due to high poliutant loading and large nuinber
of untreated parcels. The loading from these subwatersheds is expected to have an influence on
water quality within the lagoon.
Complementary Management Actions:
• New Development Site Manageinent: General attention to coinpliance with new standards and
application of innovative practices, including LID, and consideration of enhanced management.
Recorrunend that jurisdictions focus on minimizing pollutant loading and encouraging developers
to incorporate wildlife habitat into development designs. Most of the focus area is developed, but
some potential for future development exists.
• Preservation: Land acquisition opportunities are limited in this focus area to inedium and low
priority opportunities.
o Primary focus on preserving high scoring, medium-priority opportunities: LA-70, LA-135,
LA-137, LA-138, LA-139, LA-140, and LA-208.
o Secondary focus on preserving additional medium priority opportunities.
• Buffer Restoration: Buffer restoration opportunities are limited in this focus area to medium and
low priority opportunities.
o Primary focus on restoring high scaring, medium-priority opportunities: BR-125, BR-92,
BR-89, BR-215, and BR-168.
o Secondary focus on restoring remaining riparian areas among the medium and low priority
opportunities and additionai buffer restoration opportunities identified by stakeholders.
• Wetlands Restoration: Wetiands restoration opportunities are limited in this focus area to
inediuin and low priority opportuuities.
o Priinary focus on the highest scoring opportunities: WR-62, WR-64, WR-65, and WR-66.
o No secondary focus due to limited opportunity.
• Stream Restoration: Not applicable.
BMP Retrofits: Focus subwatersheds #1001, #1003, and #1005. Infiltration BMPs, such as
bioretention, and porous pavement should be investigated since soils may be suitable for these
practices.
o Monitoriiig: Pre- and post-construction monitoring of restoration and retrofit sites.
o Land treatment tracking for new development.
• Citizeu Stewardship: Focus on developing management partnerships among stakeholders and
organizations with mitigation needs. Continue and enhance cunent education efforts on lagoon
water quality and habitat.
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Agua Hedionda Watershed Management Plan — Final August 2008
{�- 7 Implementation
7.1 PRIMARY ROLES AND RESPONSIBILITIES IN CARRYING OUT THE
ACTIONS
Implementation of the WMP will depend on all stakeholders taking an active role, though the roles will
vary greatiy by action. Some actions will be implemented jointly by various stakeholders; some actions
will be led by NGOs; other actions, because of differing land use authority and permitting requirements,
will be implemented separately by local jurisdictions to address specific conditions in specific areas of the
watershed; other actions will be led by private or public sector partners needing mitigation opportunities.
The timing of actions, even certainty about their timing, will also vary greatly: some actions are cunently
ongoing, others have target dates that are time certain, while other actions have a high degree of
uncertainty regarding time of implementation.
All iinplementation actions wiil be carried out as funds are available. Excepts where actions are noted to
be part of ongoing permit or regulatory requirements, the actions recommended are considered to be
voluntary, i.e., not conducted through a regulatoiy program. Many of the actions will, however, help the
region achieve multiple goals and regulatory requirements, as outlined in Section 7.6 below.
As discussed in Section 6, two key actions which can greatly enhance implementation of this Plan and
long-term watershed management are the hiring of a part-time watershed coordinator and the formation of
a watershed council. Of the action items listed below, these are the highest priority for short-term
implementation (within 6 to 12 inonths).
The sections below briefly discuss all of the recommended iinplementation actions that were introduced
in Section 6, alid present the recolnmended roles and responsibilities by each management plan
component:
• New development site mauagement
• Preservation
• Riparian buffer, wetland, and stream restoration
• BMP stormwater retroiit
• Monitoring and enforcement
� Citizen stewardship/citizen outreach
• Funding and sustained support
Appendix H provides sulnmary opportunities by type and jurisdiction, a list of recommendations, key
groups responsible for impiementing each action, and potential funding sources.
7.1.1 New Development Site Management Actions
Leadership Role — Local Jurisdictions
High Priority Action A. Revision of local codes to incorporate recommended Basic LID techniques.
,- Pursuant to the 2007 Order, local government Co-permittees in the region are required to incorporate LID
; - requiremeilts and standards into their local codes and ordinanees by March 2010. Tetra Tech screened
` which LID techniques may be most effective to use in the Agua Hedionda watershed to meet the cui7ent
Q r�rRw,�
7-1
Agua Hedionda Watershed Management Plan — Final
2008
- water quality and quantity requirements and the WMP goals and objectives. It is recommended that local
` goveniments in the watershed incorporate the following specific Basic LID techniques into their local
LID standards and codes as preferred for development applications: reducing and disconnecting
impervious area; extended dry detention; swales or bioretention; and stream buffers. General guidelines
for establishing stream buffers in new developinent and redevelopment are provided in Appendix L.
Action B. Tracking compliance with stormwater management and LID.
Pursuant both to LID ordinance revisions enacted by local governments in March 2008 and future
revisions to be enacted in March 2010, local planning and engineering staff should review the site plan
and engineering plans for compliance with stonnwater treatment and LID requireinents. Two of the
Watershed Management Indicators are percent of future developmeut using the Basic LID techniques
recommended in Action A and percent of future developinent using BMPs. Therefore the watershed
coordinator should work with the local jurisdictions to track this indicator every 2 to 3 years.
If the planned redevelopment does not occur as represented in the model scenarios (e.g., without
treatment as required by the 2007 Order), the watershed could be at greater risk of degradation. Given
this risk, the coordinator should track the extent of redevelopment in the watershed and how it is treated.
If significantly less redevelopmeut occurs, additional BMP retrofits to untreated developinent should be
considered.
Responsible Groups: Local planning and enginee��ing departnzent, Watershed Coordinator.
Action G Implementation of the Enlzanced LID techniques as new hydrology and/or new water
quality requirements are adopted.
The RWQCB is currently drafting a sediment and a bacteria Total Maximum Daily Load (TMDL) for the
�_ "' Agua Hedionda Lagoon and Co-permittees will be soon required to adopt Hydroinodification
requirements in accordance to the 2007 Order. If, as a result, new water quality and or hydrology
requirements are adopted in the future covering the Agua Hedionda watershed, it is recolninended that
Co-permittees consider adding Enhanced LID requirements to their local codes and ordinances. Based on
a screening of the LID techniques that are likely to be most effective in the Agua Hedionda watershed, the
enhanced requirements would include stronger efforts to reduce impervious area and discomlect
impervious areas; use of porous pavement in select areas of the site, and use of rainwater capture cisterns.
This would be in addition to the "Basic LID techniques" listed above.
Responsible Groups: Local planning and engineering departments.
Action D. Feasibility study for cisterns, porous pavement, and bioretention without irrigation.
Local engineering departments should jointly seek funding ar sponsorship of pilot studies for appropriate
design and use of porous pavement and appropriate plantings for bioretention cells without irrigation. In
additioil studies should be undertaken to evaluate the cost effectiveness of using cisterns in the watershed.
The local jurisdictions should also oversee the pilot studies and share results. These studies could be
funded as pilot studies through upcoming grant opportunities, as partnership projects with local water
authorities, or as demonstration projects sponsored by product vendors.
Responsible G�oups: Local engineet�ing departments.
(� mRw,�
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Agua Hedionda Watershed Management Plan — Final August 2008
7.1.2 Preservation Actions
Leadership Role - Project Proponent and Watershed CoordinatorNVatershed
Council
High Priority Action A. Field evaluation.
Conduct a site visit of each of the 25 priority preservation sites to determine if the site has been disturbed
and to confirm that the site still e�ibits characteristics that made it a priority preservation site. Use
checklist drawn from prioritization report. If possible, organize a field evaluation (1 or 2 days) event with
watershed partners. Alternatively, the Project Proponent, once identified, could do the field evaluation.
Responsible Groups: NGOs, CA Fish and game, LIS Fish and Wildlife, local jurisdictions, project
proponent.
High Priority Action B. Identify project proponent (site-by-site).
The Project Proponent is one or more entities that wish to acquire the project site. The proponent may be
a local government or other agency, an NGO and/or a private sector entity that has mitigation needs.
Responsible GYoups: Watershed Coordinator, local ju�isdictions, NGOs
High Priority Action C. Landowner outreach.
Develop landowner outreach materials that convey a unified message about the area of interest, the
parcel's importance in protecting the streams and lagoon, potential benefits to the landowner of selling
§� and/or donating the property or conservation easeinents, etc. Develop outreach strategy (coordinating
�,_ with watershed partners) so that each landowner is contacted by the appropriate person. Verify that
landowner information developed as part of WMP information is up-to-date.
Responsible Groups: NGOs for pYivate property, local jurisdictions fo�� public p�^operty.
Action D. Coordination with cultural resources priorities.
There are confidential databases of cultural resource sites in the watershed. If one or mare of the
preservation sites also coincides with a cultural resource site, it could raise the priority of the site and
increase the potential funders for acquisition.
Responsible Groups: NGOs and Project Proponent
Action E. Secure funding sources.
Responsible Groups: Project Proponent, Watershed Coordinator/WateYshed Council, NGOs, CA Fislr
and Game, US Fish and Wildlife, ACOE, local jurisdictions
Action F. Identify/secure stewardship organizations and develop stewardship plan.
An organization must be identified to provide long-tenn stewardship of the site, which includes but is not
limited to fire prevention, invasive species control, and replanting. The Stewardship orgailization should
develop a stewardship plan and ensure that funding is provided to implen�ent it.
Responsible Groups: Project Pf•oponent and stewardship organization.
Q �re,►�va�
7-3
Agua Hedionda Watershed Management Plan — Final August 2008
Action G. Purchase property.
Purchase could include fee simple acquisition, purchase of conservation easements, donation of land,
and/or bargain sale.
Responsible Groups: Project Proponents, NGOs, CA Fish and Game, US Fish and Wildlife, ACOE, local
jurisdictions
Action H. Annual acquisition/restoration workshop.
Each year watershed partners should meet to discuss which lands have been acquired and restored in the
previous 12 months, new sites that have been identified that shouid be considered for acquisition or
restoration, new acquisition and restoration initiatives, priority sites that have been developed and
therefore need to be reinoved from consideration, proposals to revise the criteria and weighting for
prioritizing sites, new potential funding sources, etc. The new Watershed Coordinator and Watershed
Council should organize and host the event.
Responsible Groups: Watershed Coordinator/Watershed Council, NGOs, CA Fish and Game, US Fish
and Wildlife, ACOE, local juYisdictions
Action I. Update/maintain prioritization tool.
The WMP prioritization tool should be updated aunuaily based on information from the annual
acquisitioi�/restoration workshop.
Responsible Group: Wate�shed Coordinator
7.1.3 Riparian Buffer, Wetland and Stream Restoration
Leadership Role — Project Proponent
Note: The New Development Site Managelnent actions include preservation of stream buffers in future
development applications in the watershed. This is separate froin the recommended riparian buffer
restoration projects (see New Development Site Management High Priority Action A).
High Priority Action A. Identify project proponent (site-by-site).
The Project Proponent is one or more entities that wish to acquire the project site. The proponent may be
a local govenlment or other agency, an NGO and/or a private sector entity that has mitigation needs.
Responsible Groups: Watershed Coordinator, local jurisdictions, NGOs
High Priority Action B. Field evaluation.
Conduct a site visit to confirm the site has not been disturbed and to confirm that the site meets criteria
which made it a priority buffer, wetland, or stream restoration site. Use checklist from WMP
prioritization report.
Responsible Group: Project proponent.
High Priority Action C. Landowner outreach.
Verify that landowner information developed as part of WMP information is up-to-date. Develop
outreach materials regarding the importance of'the site, generally what is being proposed, the
euvironmental benefits of the project, and the potential tax benefits to the property owners.
Responsible Group: Project p��oponent, NGOs
O �u►'�
7-4
Agua Hedionda Watershed Management Plan — Final August 2008
-- - Action D. Contact ACOE and other permitting agencies.
�
` Have pre-design meeting with the ACOE, CA Fish and Game, local engineering departments, and other
potential permitting agencies to determine which types of permits wili be needed for the project site.
Responsible Group: Project Proponent
Action E. Coordinate with local trails and infrastructure plans.
Determine if the site is part of a local water, sewer, road, or other infrastructure plan ar a trails plan that
would either nullify restoration of the site or would complement restoration of the site.
Responsible Group: Project Proponent
Action F. Coordination with cultural resources priorities.
There are confidential databases of cultural resource sites in the watershed. If one or more of the
restoration sites also coincides with a cultural resource site, it couid raise the priority of the site and
increase the potential funders for restoration. Alternatively, a cultural resource site may nullify
disturbance of the site %r restoration.
Responsible Groups: Project Proponent and NGOs
Action G. Develop design and cost esfimates.
Planning-level, conceptual costs were estimated and presented in the WMP for the buffer, wetland and
stream restoratioil opportunities however, additional analysis, modeling and design work will be required
to support the restoration opportunities and to develop detailed cost estimates for funding allocation.
Responsible Groups: Project Proponent
Action H. Secure needed permits.
Depending on the nature of the proposed activities projects, agency permits inay be required, including
Coastal Development Permit for construction within the Coastal Zone, Section 404 Permit from the U.S.
Army Corps of Engineers construction impacting to jurisdictional waters of the U.S., 401 Water Quality
Certification from the RWQCB for conditions placed in the Section 404 Permit to protect water quality,
Streambed Alteration Agreement from California Departinent of Fish and Game due to iinpacts to
jurisdictional wetlands and streambeds, and Local Development Permits (i.e., grading, building or other
construction related permits). Section 7 consultation under the Endangered Species Act may be required
if a Coips 404 pei7nit is needed, particularly in the case where a project wiil be in critical habitat or where
endangered species are located. Proposed watershed management projects inay also require an evaluation
under the California Environmental Quality Act (CEQA), which requires state and local agencies to
evaluate the euvironmental impacts of their actions. If a project involves the use of federal funds, an
evaluation under the National Enviroiunental Policy Act (NEPA) may also be required.
Responsible Groups: Project Proponent
Action I. Secure funding sources.
A variety of fuuding optious may be used to support restoration projects depending on the type of project
and how it matches up with funding sources.
Responsible Groups: Project Proponent, Watershed Coordinator/Watershed Council, NGOs, CA Fish
and Game, US Fish and Wildlife, ACOE, local ju�°isdictions
(� rn,Krr�
� -'� 7-5
Agua Hedionda Watershed Management Plan — Final August 2008
Action J. Identify/secure stewardship organizations and develop stewardship plan.
An organization must be identified to provide long-term stewardship of the site, which includes but is not
limited to fire prevention, invasive species control, and replanting. The Stewardship organizatiou should
develop a stewardship plan and ensure that funding is provided to implement it.
Responsible Groups: Project Proponent and stewardship organization.
Action K. Implement projects.
Res�onsible Groups: Project Proponents
Action L. Annual acquisition/restoration workshop.
Each year watershed partners should meet to discuss which lands have been acquired and restored in the
previous 12 months, new sites that have been identified that should be considered for acquisition or
restoration, new acquisition and restoration initiatives, priority sites that have been developed and need to
be removed from consideration, proposals to revise the criteria and weighting for prioritizing sites, new
potential funding sources, etc. The new Watershed Coordinator and Watershed Council should organize
and host the event.
Responsible Groups: Watershed Coordinator/Watershed Council, NGOs, CA Fish and Game, US Fish
and Wildlife, ACOE, local jurisdictions
Action M. Update/maintain prioritization tool.
The WMP prioritization tool should be updated annually based on information from the annual
�,
acquisition/restoration workshop.
� ��� Responsible Group: Watershed Coordinator
�_.,
7.1.4 Stormwater BMP Retrofit
Leadership Role — Local Jurisdictions
Action A. Site selection and feasibility (untreated areas).
The WMI' identified areas that have the highest pollutant loading and stormwater volume impacts and
that also were developed before stormwater BMPs were required. These "untreated" areas need to be
surveyed to identify promising sites for BMP retrofits and to screen for project feasibility oll the highest
ranking sites. As redevelopment is monitored over time, untreated areas slated for redevelopment should
be considered for BMP retrofits if redevelopment trends change and the land is likely to remain
untreated. Each local govenunent engineering department in the watershed shouid conduct individual
surveys for untreated areas within their jurisdiction.
Responsible Group: Local enginee��ing departments
Action B. Collection of additional site data.
The WMI' identified five potential demonstration sites that may complement the proposed stream
restoration projects. Additional data need to be collected to assist in BMP selection, sizing, and location.
Responsible Group: Local engineering departments (individual suY-veys foY untreated aYeas within their
jurisdiction)
(� rrrsw�
� -�� 7-6
Agua Hedionda Watershed Management Plan — Final August 2008
r Action C. Landowner outreach.
f
- Verify that landowner information developed as part of WMP information is up-to-date. Develop
outreach materials regarding the importance of the site, generally what is being proposed, the
environmental benefits of the project, flood reduction benefits to the property owner, and the potentiai fee
waivers or other incentives for the property owners.
Responsible Group: Local engineering departments
Action D. Preliminary design and cost estimate.
Based on final selection of BMPs for the site, develop preliminary design and cost estimates.
Responsible Group: Local engineering depaYtments
Action E. Secure needed permits.
It is anticipated that BMP retrofits on the demonstration sites and in the uutreated areas will be on sites
that have been highly disturbed in the past and therefore would not require the types of permits required
for restoration projects. However, some permits may be required, depending on the BMP selected and the
site location.
Responsible Group: Local engineering depaYtments
Action F. Secure funding sources.
A variety of funding options may be used to support restoration projects depending o11 the type of project
and how it matches up with funding sources.
Responsible Groups: Pf•oject Proponent, Wate�shed Cou�zcil, NGOs, CA Fish and Game, US Fish and
Wildlife, ACOE, local jurisdictions
Action G. Implement projects.
Responsible Group: Local engineering departments
Action H. Monitor effectiveness/efficacy of demonstration projects.
Given that the use of LID techniques is relatively new in the San Diego region, there is a need to monitor
the effectiveness of these techniques in managing stormwater peak volume and pollutant loading. This
monitoriug should include measuring inflow aud outflow of the BMPs as well as downstream conditions.
�esponsible Groups: Local engineering departnients and u�ziversities
7.1.5 Monitoring and Enforcement
Leadership Role - Local Jurisdictions and NGOs
Action A. Long term stream and lagoon monitoring program.
Collect and assess physical, chemical, and biological data for streams in the watershed and the lagoon
through a long-tenn monitoring program. This inonitoring is to supplement current monitoring by Co-
permittees (see recommendations in Section 6.5). Periodically report on monitaring results using baseline
water quality data from the WMP and water quality goals as benchmarks for comparison.
Responsible Groups: Co perrnittees, NGOs, universities
a �r�w,�ai
7-7
Agua Hedionda Watershed Management Plan — Final August 2008
- Action B. Long-term wetlands monitoring (CRAM).
; Periodically collect and assess CRAM data for wetland areas of the watershed. As a part of the WMP, the
Southern California Coastal Water Research Project (SCCWRP) conducted a one-day CRAM training
event which was well attended by NGOs, agencies and local jurisdictions. A partnership with SCCWRP,
through a local NGO or university would be a good partnership to implement this action long-term. It is
important that the data be fully analyzed and made available to stakeholders at a central location such as
the Agua Hedionda Lagoon Discovery Center. Periodically report on monitoring results using CRAM
monitoring results from the WMP as a benchmark for comparison.
Responsible Group: NGOs
Action C. Inspections and maintenance of sanitary sewer systems.
Check lines for leaks, illicit connections, and overflows. Inspect sewage conveyance systems (pipes,
pump stations, manholes) to ensure proper functioning. This ongoing work is included in the new
Sanitary Sewer Order (State Waste Discharge Requirements (WDR) Order 2006-0003-DWQ)
Responsible Groiap: Local wastewater/sewer departments
Action D. Monitoring effectiveness/efficacy of BMP demonstration projects.
Given that the use of LID techniques is relatively new in the San Diego region, there is a need to monitor
the effectiveness of these techniques in inanaging stormwater peak volume and pollutant loading. This
monitoring should include measuring inflow and outflow of the BMPs as well as downstream conditions.
Universities would be appropriate potential partners in this effort.
Responsible G�oups: Local engineering depaYtments and universities
Action E. Inspections and maintenance of storm drainage systems.
Increase efforts to clear and maintain storm drains and drainageways to remove deposited materials. For
starm drain pipes, cleaning is especially needed with pipes too flat to be self-cleansing. Clearing of
drainageways should involve routine inspection of drainage channels and creeks. This ongoing work is
also included in "Regionai Channel Mainteliance" program. The Regional Charulel Maintenance
Workgroup has developed a guide for maintenance activities which should facilitate this recommended
action.
Responsible GYoups: Locczl jurisdictions
Action F. Construction site inspection and enforcement action.
During construction, conduct onsite iilspections and take enforcement actions, as needed. This ongoing
wark is also included in the 2007 Order.
Responsible Groups: Local ju�isdictions
Action G. Stormwater �MP inspection and enforcement.
Regularly inspect stot-mwater controls to certify their proper functioning aud to require repair of failing
systems. This action is also inciuded in the 2007 Order.
Responsible Groups: Local juYisdictions
Action H. Tracking key watershed management plan indicators.
In order to measure the effectiveness of the WMP and the actions taken in meeting the goals and
'�� .- ' objectives, it is important to track the WMP key indicators over time. These indicators include, but are not
Q r�re,►�sc�
7-8
Agua Hedionda Watershed Management Plan — Final August 2008
limited to, stream water quality, riparian habitat extent, percent change in the watershed's natural area,
location of mature tree species, percent imperviousness, percent of new development implementing LID,
etc. Tracking of key WMP indicatars will require ongoing support, commitment and funding. Many of
the indicators to be tracked will require analysis using GIS tools and modeling. Although some of the
indicators can be tracked by NGOs, complete implementation will best be performed by the Watershed
Coordinator or hiring a consultant through the Watershed Council or NGOs. If implementation of the
WMP becomes an integral part of local jurisdictions' WLTRMP and TMDL implementation programs this
action couid fall under their assessment purview.
Responsible Gfroups: Watershed Coordinatof /Watershed Council., NGOs, local jurisdictions
7.1.6 Citizen Stewardship/Public Outreach
Leadership Role — Watershed Coordinator/VVatershed Council, Local
Jurisdictions
High Priority Action A. Collaborative Agua Hedionda Watershed Council.
This includes creation of a permanent watershed council supported by a part-time watershed coordinator.
It is recommended that each local government have an elected official as representative on the board of
the Watershed Council. In addition to local jurisdictious, the watershed council will be stronger if it
contains members from agencies with authority iu the watershed (wildiife agencies, US Army Corps of
Engineers, RWQCB, sewer agencies and water districts, etc.). To be most effective, the Watershed
Council should be formalized with an agreeinent in the form of a Memorandum of Understanding, Joint
Powers Agreeinent or Memorandum of Agreement between local jurisdictions. The Council may also
wish to form as a non-profit organization. It is also recommended that the Council have several
&' T stakeholder cormnittees: watershed partners, technical advisory committee, and funding committee.
�
��"� Responsible Group (for forming Council): local jurisdictions
Action B. Reporting to local governments and local boards.
The Watershed Council should meet with these boards during their regularly scheduled meetings on an
annual basis to update them on the needs, benefits and progress of the WMP iinplementation.
Responsible G��oup: Watershed Coordinato�/Watershed Council
Action C. Distribution of educational materials.
Educational materials can include brochures, agency bill inserts (brief flyers in water bills), press releases,
presentations to schools and civic groups.
Responsible GNoups: Watershed CooYdinator/Watershed Council, local jurisdictions, NGOs
High Priority Action D. LID workshops and training.
The workshops should include general LID education, however they should focus on local knowledge
obtained from the modeling effort in this WMP (see Section 6.1 and Appendix J). It is recommended that
workshops and training for municipal staff is performed by other professionals or professional
organizations.
Responsible Groups: Local jurisdictions, NGO
(� ror�w�
� -�� 7-9
�.
�
Hedionda Watershed Management Plan — Final
Action E. Annual awards program.
Auqust 2008
An annual awards program is recommended to encourage and recognize local efforts towards watershed
protection. Awards should be considered for individuals, Public Officials, developers, businesses, or
NGOs.
Responsible G�oup: Watershed Coordinator/Watershed Council
Action F. Annual progress workshop.
This workshop would allow watershed partners to discuss progress made in implementing the WMP and
new initiatives for the coming year.
Responsible Groups: Watershed Council NGOs, local jurisdictions
Action G. Management partnerships.
Establish partnerships within the watershed to leverage programs towards project impieinentation.
Responsible Groups: Watef shed Coordinator/Wate�shed Council, Local jurisdictions, Unive��sity, Private
mitigation proponents (Developers, Poseidon, Caltrans, Cabrillo, Power Plants), US Fish and Wildlife,
CA Fish and Game, SANDAG, etc.
Action H. Aqua Hedionda Website.
The website should maintain prograin inforination including an overview of the WMP, announcements,
events calendar, meeting archives, educational material ongoing projects, and links to other related
programs. It should be maintained on a regular basis which will include staff'time to prepare updates and
funding to support website hosting.
Responsible Group: Watershed Coordinator/Watershed Council
7.1.7 Funding and Sustained Support
Leadership Role - Watershed Coordinator and Local Jurisdictions
High Priority Action A. Grant Programs.
Successfully tapping into grant programs will involve identifying target grant programs, matching
projects to grant prograins, identifying partnerships and matching funds, contacting appropriate agencies,
and preparing grant applications. A wide range of potential funding optious are discussed in Section 6.7.
The responsibility for obtaining grant fuuding falls with the Watershed Coordivator, local jurisdictions
and NGOs as grant applicant and project sponsors.
Responsible Groups: Watershed Coordinator, local jurisdictions, NGOs
High Priority Action B. Coordination with agencies.
Identify target agencies and funding opportunities through agency programs. Meet quarterly with
appropriate agencies to discuss priarities and opportunities.
Responsible Groups: Watershed Coordinator, local juYisdictions, NGOs
High Priority Action C. Mitigation programs.
Identifying win-win opportunities for addressing mitigation needs and implementing
preservation/restoration projects requires aligning projects with mitigation banks and in-lieu fee
�
7-10
Agua Hedionda Watershed Management Plan — Final August 2008
programs; obtaining agency support for mitigation banks and in-lieu fee programs; and conducting
� outreach to the development community, public and private sector entities in need of mitigation credits.
Responsible Groups: Watershed Coordinato�^, local juf�isdictions, NGOs
High Priority Action D. Watershed Council Support (Watershed Coordinator Support).
The Watershed Council and Watershed Coordinator will require startup and ongoing funding support.
Key steps to securing this support include preparing a scope for the watershed council and staffing needs
($); obtaining local support from agencies, jurisdictions, NGOs and the business community; identifying
grant/funding opportunities and pursue with grant proposals; explore redirection of City fees.
Responsible GYoups: startup — local jurisdictions and NGOs; ongoing support — Watershed Coordinato�;
local jurisdictions, NGOs, other watershed partners
7.2 TIMELINES AND MILESTONES
Clearly some recommended actions take priority, either because they are most essential to preservation
and restoration of the Agua Hedionda Watershed, or because they are required before other actions can
move forward, or both. A number of the recommended actions are ongoing, particularly the monitoring
and enforcement activities. Appendix H, Implementation Actions, provides proposed timelines for each
of the recominended WMP actions, noting where timelines of certain actions are yet to be determined.
Below are the proposed timelines for High Priority Actions.
• Hire part-time Watershed Coordinator — Septeinber 2008-March 2009
�� � • Establish Watershed Council — September 2008-September 2009
• Conduct field evaluation of priority preservation sites — August 2008-February 2009.
• Identify project proponents for preseivation and restoration projects — TBD (potentially concerted
effort could begin after hiring watershed coordinator)
• Conduct field evaluation/verification for the restoration sites— TBD dependant on iildentifying
project proponents
• Conduct landowner outreach for preservation and restoration projects — TBD dependant on
indentifying project proponents
• Host annual preservation/restoration workshop — August 2009 (and anuually thereafter)
• Conduct LID workshops and training — TBD (dependent on local jurisdiction resources and
grants)
• Revise local codes to include Basic LID techniques and standards — March 2010
• Track key watershed indicators — 2011-2012 (every 3- 5 years thereafter)
� Secure Funding —TBD (potentially concerted effort could begin after hiring watershed
coordinator)
Ongoing progralns that affect Agua Hedionda watershed planning and funding efforts also have key
milestones that should be tracked over the next several years. These program milestones include:
� Requirements for Sanitary Sewer Order (State Waste Discharge Requirements (WDR) Order
2006-0003-DWQ) for Wastewater Coilection Agencies
• Water Conservation Ordinance adoption by local jurisdictions
t�l'�'w►'�
7-11
Agua Hedionda Watershed Management Plan — Final August 2008
r
• MSCP and MHCP (including subarea and local plans) implementation (County and cities)
- • Lagoon TMDL
• Reissuance of San Diego County Municipal Stormwater Permit (2007 Order)
• IRWNIP Update — Prop 84 Planning Grant
• Stormwater Grants
• Flood Control Grants
7.3 ESTIMATED COSTS AND FUNDING
Estimated Cost and Funding
Implementation of the WMP will require funding and sustained support. Estimated cost for some of the
key WMP components are summarized below. The cost of the citizen stewardship actions is yet to be
determined. These costs are also summarized in Appendix H by type of opportunity and jurisdiction in
which the opportunity is located.
New Development Site Management
Local governments' revision of codes and ordinances to incorporate the use of LID is an existing
requirement, not an added cost to local jurisdictions and the development corrununity of the WMP.
Studies have shown that use of LID can in some cases reduce overall development costs, depending on
the site design. These reductions are often found in reduced paving costs (due to narrower streets, shorter
driveways, etc.), reduced infrastructure costs (e.g., using swales in place of curb and gutter), and reduced
�- grading costs. Cost saving site designs are more often achieved in rural and suburban development rather
� � � � than highly urbanized developments.
Preservation
25 properties
387 acres to preserve
�38 to $95 million iu total acquisition costs (fee siinple acquisition)
Cost per acre: $45,000 to $280,000 per acre
Potential Funding Sources: Mitigation Banks and In-lieu p3•ogram; P�ojeci Mitigation Needs (developers,
Caltrans, etc.); Gf�ants — SWRCB (Prop 84), DWR (Prop 84 and 1 e), San Diego County ZRWM (Prop 84),
EPA 319(h), CA Ocean Protection Council, Wetland Recovery, State Ti�ibal and local Government
(EPA); MHCP and MSCP i�nplementation, U.S. Fish & Wildlife, California Departn2ent of Fish & Ganze
Riparian Buffer Restoration
27 properties
129 acres to restore
$10 to � 19 million in total acquisition and restoration costs
Total cost per acre: $42,000 to �160,000 per acre
Potential Funding Sources: Mitigation Banks and h�-lieu programs
Project Miiigation Needs (developers, Caltrans, SANDAG TYansnet, etc.); G��ants —SWRCB (Prop 84),
DWR (Prop 84 and 1 e), San Diego County IRWM (Prop 84), EPA 319(h), CA Ocean Protection Coi�ncil,
Wetland Recovery, State Ti�ibal and local Government (EPA)
(�j r�rw►,�
� -'� 7-12
Agua Hedronda Watershed Management Plan — Final August 2008
�`
��.
Wetland Restoration
12 properties
47 acres to restore
$2 to $10 million in total acquisition and restoration costs
Totai cost per acre: $42,000 to $250,000 per acre
Potential Funding Sources: Mitigation Banks and In-lieu programs
Project Mitigation Needs (developers, Caltrans, SANDAG Transnet, etc.); Grants — SWRCB (Prop 84),
DWR (Prop 84 and le), San Diego Cozrnty IRWM(Prop 84), EPA 319(h), CA Ocean Pi�otection Council,
Southern California Wetland Recovery Project, State Tribal and local Govern�nent (EPA)
Stream Restoration
12 reaches to restore
32,000 feet, or 6 miles to restore
$10 to $11 million in restoration costs
Potential Funding Sources: Mitigation Banks and In-lieu prograrrzs
PYoject Mitigation Needs (developers, local jurisdictions' CIP project, Caltrans, SANDAG Ti�ansnet,
etc.); Grants (SWRCB (Prop 84), DWR (Prop 84 and 1 e), San Diego County IRWM (Prop 84), EPA
319(h), CA Ocean Protection Council, Wetland Recovery, State Tribal and local Government (EPA)
BMP Retrofit Demonstration Projects
Six BMP retrofit sites were identified. Some sites included multiple BMPs on the conceptual design.
Table 7-1 provides conceptual level unit costs associated with each BMP:
Table 7-1. Stormwater Retrofit Costs
BMP Unit Price'
Bioretention $6.00/cf
B ioswales $1.00/cf
Cisterns $7.5K/1,800 gallons
Depressed medians $1.00/cf
Grading $2/cy
Media filter $4.5/cfs -$3k/catch basin
Pervious paving $10 - $15/sf
Trees $3.50/sf
Shrubs $1.75/sf
Trash Traps $350/opening
���� Potential Funding Sources: Local jurisdictions, vendors; Grants (EPA 319)
(� rrrRwt�»
� -'� 7-13
Agua Hedionda Watershed Management Plan — Final August 2008
- Monitoring and Enforcement
� Many of the monitoring and enforcement actions fall within current local government responsibilities and
do not pose additional manageinent cost, e.g. inspections/maintenance of sanitary sewer systems;
inspections/maintenance of storm drainage systems; construction site inspection, stormwater BMP
Inspection, and Co-permittee stream and lagoon monitoring. The cost of the enhanced monitoring, of
continued CRAM monitoring, and of tracking watershed indicators has not been determined.
Potential Funding Sources: Local juj�isdictions; Grants
Citizen Stewardship
Cost to be determined
Potential Funding Sources: SWRCB (P�-o� 84); DWR (Prop 84 and 1 e); San Diego Counry IRWM (Prop
84); EPA 319(h); CA Ocean P�rotection Council; Southern California Wetland Recovery Project, State
Tribal and local Government (EPA)
Funding and Sustained Support
$10,000 grant for forming Watershed Council (one time cost)
$100,000 annually far watershed coordinator (preliminary estimate including salary, fringe, and
overhead)
Potential Funding Sources: Grants: Southern California Wetland Recovery Project, Department of
Conservation; Local jurisdictions; Local businesses, Private Foundations
��� ��� 7.4 ESTIMATED IMPACTS AND BENEFITS
Below we present how each of the key actions contribute to preservation, restoration and enhancement of
the watershed, where possible using results of the watershed and site scale modeling of the Agua
Hedionda watershed as well as accepted literature values. The infonnation can be used to help educate
citizens, businesses, and elected officials about the benefits of the actions recommended and used in grant
appiications to support implementation efforts.
While the benefits are discussed iudividually, it is important to note that the recommended actions work
together to achieve greater functional uplift for the watershed. In fact, the Focus Areas are designed to
leverage actions and maximize overall preservation and restoration benefits for the Agua Hedionda
watershed.
7.4.1 LID Implementation Benefits
LID Implementation Benefits
When looking at cumulative pollutant loading and peak volume near the mouth of the watershed, the
watershed modeling indicates that if certain land conversion (e.g., from agricultural to LID development)
is realized, Basic LID techniques are ilnplemented for future development aud redevelopment, and land
preservation is achieved, communities in the watershed should be able to "hold the line" on pollutant
loading and peak discharge. Implementing Enhanced LID techniques would achieve even greater
cumulative benefits in the watershed.
What are the LID benefits on a site scale? Table 7-2 through Tabie 7-5 show the results of the site
pollutant loading analysis/modeling of different types of development in the Agua Hedionda watershed.
The percentages reflect the reduction in load from an untreated site with defauit percent impervious area
assuinptions. The Basic LlD iinpleinentation scenario assumes adoption of practices meeting the 2007
l=`J �►�
7-14
Agua Hedionda Watershed Management Plan — Final
August 2008
r
order, with minimai incorporation of additional LID. The Enhanced LID implementation scenario
` assumes the development site not only meets the 2007 order requirements, but additional LID measures
have been incorporated with some consideration for economic feasibility. The Enhanced LID scenarios
are just an example of what might be achieved; other configurations are possible, and may be influenced
by changes to regulations resulting from pending TMDL and hydrology implementation requirements.
Details about the scenarios are discussed in Section 6.1 and Appendix J.
It is estimated that implementation of Basic LID techniques for new development would achieve 60
percent to 70 percent reduction in sediment load and an 88 percent reduction in fecal coliform load, which
are key problem parameters for the watershed and lagoon. It is expected to also achieve a 35 to 45
percent reduction in Total Nitrogen and a 25 to 30 percent reduction in Total Phosphorus.
Iinplementation of the Enhanced LID techniques are predicted to provide substantially greater reductions
in Total Nitrogen and Total Phosphorus, especially for multi-family, commercial, and industrial
developinent (e.g., approximately 50 to 65 percent reduction in Total Nitrogen compared with the 35 to
45 percent reduction under the Basic LID approach).
���
�
(� r�uw,s�
� -�� 7-15
Table 7-2. Medium Density Residential LID Benefits
Table 7-3. Multifamily Residential LID Benefits
Table 7-4. Commercial Development LID Benefits
Agua Hedfonda Watershed Management Plan — Final August 2008
;
;`
The previous tables deinonstrate the potential benefits of using stormwater management and LID
techniques to reduce pollutant load washoff from stabie, developed sites. However, an additional impact
from development is the increase in peak flow and runoff volume resulting of conversion of natural land
cover to developed pervious and impervious surfaces. What results is an increased risk of channel
erosion, from both higher peaks and longer durations of flow. Figure 7-1 compares design storm event
hydrographs for the Basic versus Enhanced LID scenarios for multifamily development. As seen in the
Basic LID hydrographs on the left, the extended dry detention basiu designed under the 2007 order
requirements reduces the peak flow to values lower than existing conditions (assumed to be undeveloped
land) for all three design storms. However, for the 5- and 10-year events there is a period of time when
the post-with-BMPs flow exceeds existing conditions, resuiting in a longer duration of potentially erosive
conditions in the receiving stream. The Enhanced LID scenario incorporates large cisterns (with assuined
water reuse) that provide additional runoif storage, and greatly reduce flow duriug the most potentially
erosive portion of the post-with-BMPs hydrograph, nearly matching the existing hydrograph. LID
�. techniques can not only improve pollutant removai, but also reduce total runoff volume and change storm
event hydrologic response to more closely mimic natural conditions. Hydrographs for Mediuin Density
Residential, Commercial, and Indust�ial development are provided in Appendix J.
� r�rsw,�rs�
� -�� 7-16
Table 7-5. Industrial Development LID Benefits
Agua Hedionda Watershed Management P/an — Fina/ Ar�gust 2008
Minimal LI�
120
10D _
sa —Pazi...��.oM
60
� aOou�n v�ou�¢ „ou 9r29-M1rsbrHou�w
20
200
150 5-y� 24-Fr sbrm
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2W I
zao . , o-v, �a-n. �m�,.,
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100
BO I poxLmtnemv
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� 4O_ Ho�irz �iou ZQM1rsbrm n
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Figure 9-t. Projected Hydrographs for Basic L/O antl Enhanced UO Scenarios for MWtifamily
Development
7.4.2 Preservation Benefits
In thc Agua 4lcdionda watcrsM1cd, land proscrvaGon dircctty supports thc W'PG �oal "prcccrvc 6aL itat in
Lhe wutcrshcd" (Goal #2)_ It also supports thc goals to restorc watcrshcd functions (Goal #3), antl to
suE�por[ complia��cc with r �.ulamry requircinc��[s (Goal #4).
WhSlc thc habCr t bc��cfts o£ land prescrvaffon a c df£Ficult to yuanG£Y, thc watcrshc-d modali��g resWts do
shed light on the bencflts ofpollution and �vnoft piroven[ion. For cxainple, ifthe zoning for a particuLar
yarccl nllows mc-diun� dcnsity r sidcntixl devalopn�ent, tl�cn devebping tl�c la��d would gener�te doublc
swrmw�tcr runoffand doubic thc iotal phosphorus per acrc runoffthan prescrving thc land in opcn spacc
(saa Tablc "]-C). If zoiiin� allows higL dm�sity r siden�ial, f� woulcl gcncrate approximately i timcs the
storn�watcr r�no{f and 20 cinics thc rotal phospho�v�s es presc�ving it in oPcn spacc. Thc tablc shows ihat
prc - ut3on oCland can eienilTcanily redum Cccal culiforni, to�al nitrogen, mtal pl�osphorua. and sur£acc
�unoi'Pvolu�nc on a sim basis.
Table 9-6 suggcsts thnt scAimcnt loading. in somc cascs, can bc Iowcr or similar whco dcvGopcd
mparcd to whcn prescrvcd. Ffrst, thc waicrshcd Iand [ i its natural statc has crosivc soils and hieh
scdimcn� loading_ Whcn a.-a dcvclops. it has morc impervious a and Icss natural a a chnt can
-odc. 1 iowcvcr, f� f. mport�in� to no�c tM1ut thc ligures shown in Tebl v �-6 do not 9nc9udc tl�c sednncnt
npacts duc m grcatcr�impervious a �nd a iatcd stormwatcr volumc (i c_. hydromodlficaGon and
strcan� banh c n). Tliercfore, o cr�ll scdiincn� reJuction bcnciits cam bc bcucr i ndcrstuod by
comparing both tl c scdimcnc loading and surfacc runofFcolumns to opcn spacc condiuons.
Q ���w�
Agua Hedionda Watershed Management P/an - Fina/ August 2008
For each parce] targeted fur 2cquisition, pollutant loading nnd runoff prevention can be estimateA by
mamhing ihc currcnt zoning o£tl�c propcny to tl�c appropriatc ]aiid u cutcgory i�� Tablc ]-6. MWtipty
Ihe �cros by thc loading and runoFf factora (cg_, TP Ib/ac/yr) For both thc zoncd land u_ c and thc preserve
oycn spaca. Thc dif�ercoce between tlie cwo will yield the loacling/�vnoffreduction benelit.
Prescrvut9ou of'tlic- priority parecls e n hava a signiliexnt iinpaet on loeeJizcd strcain watcr qual9ty,
su'can�bank stability, cind haUitai divcrslty. In tandcnz witl� thc. othcr WMP acGons, prescrvation can also
]�alp reswra water qualiry and hydrology Punctions on a waiershed scale.
Table 9-6. Open Spac¢ Praservation Benefits
Fecal Surfaca
Coliform TN TP 5¢diment Runoff
Lantl Usa #/ac/yr Ib/ac/yr Ib/ac/yr ton/ac/yr in/yr
Preservetl Open Space 'I .60E�D9 '134 O.OS 0.64 1.23
Medium �ensity Rcsitlential 222Ew'10 'I.55 O.t2 0.52 248
LowOensityResitlential 2.42E+�0 �.81 O.t4 OJ6 2.94
VeryLowDensityResiden�ial 243ET�0 2.'12 0.�4 t24 3.54
LL Commercial/Offce/Inslifut�onal 4_14E�09 4.67 0.43 0.60 4.98
Warehouse/IntlusVial/Transportation S.00E+09 4.�5 0.50 0.49 S86
MWti-FamilyResitlential 9.3]ENO ].30 0.91 0.42 6.04
High Density Residen[ial 'I.'IOE+� 1 ].96 t.02 0.82 6.86
Heavy Commercial Z32E+-09 6.59 OJ3 0.60 8.46
Loading rates basetl on average annual motlel s�mulation of fu[ure land use scenano. I[ includes BMP trealment tor
Gwble lantl u
7.4.3 Riparian Buffers Restoration Benefits
Strcan� bufl'crs x i�nportan� toul i i �hc protcction and restoration ol'watcrahed lunc�ions. A s�ublc,
vv-gctated svcambank is � ial componcnt oFstrcam channd protcction and scdimcnt rcducGon.
Withoui vegetation along a�sn-ca�7i_ streambanks c�u slough off���d may beconie �nore susceptible tu
Failurc during high flow cvcn[s. Riparian bid'fcrs also scrvc .as tiltcis f r scdimcnt cind othcr pollutants
such as nuu'icnts in runoi�ffi'om adj¢ccnt land.
BuRers with widths oT anP�'oxim�tcly SO to I00 Fecc (or €�'catcr) wn providc water quality functions_
stabilizc thc strcambunlc, n��d protcct aquat9c hebftut (Wcngcr, 1999). TM1c bcncfits for strcan stabfGty a
di�cult lo �uan�ify. Howcvcq thc flltcring and drnitriFlcation cffccts ofriparian buffcrs and Fltcr slrips�
havc bcco studfcd cxtcnsivcly. Cicncral cs[Cni�ims of'cl'fcctivcncss at rcducSnn pollu[ants [� - rof{ fi-om
�djacv-ni Innd arc a� Followsc 90 to > 90 po�ccnt rc<iuction in TSS. 50 io 90 F�crccnt rcduction�in TP_ and
50 to >90 perccnt oi TN (Unsicker c� al., 1984, Wenger ¢t at, 1999, CASQA BMP Manual). The
effcctivcncss v s bascd on widch_ vcgctaGon rypc subsurfacc flow paths (parGcularty For N), anA
posiGo�� u� thc la��dscapc.
7.4.4 Wetland Restoration Benefits
Thc bcncFts of wctland resmration fndudc flow con�roL, nutricnt cycline, end habStai divcrs-ity. Thcsc
wcUand brneflxs. howcvo'. arc ditl�cWt to modG and quancify_ In thc Agua Hcdiondn watcrsM1cd, wetland
� cstoration eip�ports sevcrxl ol �he WPG goals, includi��g ms�orine s nd enhancing habitat in 1he waterslicd
Q.�...�..o.
Agua Hedionda Watershed Management Plan — Final Augusf 2008
(Goal #2), restore watershed functions (Goal #3), and supporting compliance with regulatory
requirements (Goal #4). Wetland restoration actions can also strengthen other WMP actions, such as
buffer restoration, stream restoration, and land preservation.
7.4.5 Stream Restoration Benefits
Instream sedimentation combined with contribution from upload sources is one of the primary collcerns in
the Agua Hedionda watershed. Sediment from instream sources contributes to impairment in the lagoon
as weli as degradation of aquatic habitat and associated biological communities in Agua Hedionda Creek
and its tributaries. The purpose of the proposed stream restoration projects described in Section 6.3 is to
stabilize stream channels in order reduce sediment generated by eroding streambanks and incising
channels. The specific benefits of these projects are difficult to quantify based on information gathered to
date. Nonetheless, reducing instream sources of sediment is expected to improve water quality, enhance
aquatic habitat, stabilize morphologic instabilities, decrease sediment loading to the lagoon, and
ultimately improve the diversity and abundance of aquatic communities in both the lagoon and its
tributaries.
7.4.6 BMP Retrofit Benefits
Table 7-7 show the results of the site pollutant loading analysis/inodeling of the conceptual designs of
different types of BMP retrofit demonstration sites, located near proposed stream restoration sites, in
terms of percent reduction of annual flow volume and poliutant loading. This information allows for
coinparison between sites and provides a general indication of the overall performance of retrofit benefits
throughout the watershed. The performance of SW-1 is dominated by the extended dry detention basin
� that treats the entire drainage area, but the cistem does contribute to the reductions, especially for runoff
������ volume. The performance for SW-2 is less than the other sites for TSS and nutrients, which is not
surprising since the BMPs treat less than 10 percent of the total drainage area. SW-3 and SW-4a have
similar performance in terms of percent removal, and reflects the similarity of treatment between the sites.
SW-4b and SW-5 are also very similar; both represent drainage areas for median swales treating adjacent
road area.
The analysis demonstrates that the retrofit BMPs provide pollutant load and runoff reductions for their
receiving watersheds. Furthermore, the BMPs reduce storm event peak flow and runoff volume, an
important componeut of initigating risk of geomorphic change in streams receiving the runoff. Note that
the drainage area delineations and impervious area estimates used in the analysis above should not be
used for engineering design.
O ��rx,��
7-19
Table 7-7. Percent Annual Pollutant Load Reductions for Each Retrofit Site
Hedionda Watershed Management Plan — Final
2008
������ 7.5 ADAPTIVE APPROACH
" Watershed management is ongoing work that must respond and adapt to changing conditions. The WMP
recommends several procedures or actions that enable this adaptive approach: long-term monitoring;
management indicators for plan performance evaluation; and a Watershed Councii that can make plan
updates.
Monitoring
This WMP recommends that local jurisdictions continue to collect and analyze chemical, physical, and
biological data for both the streams and the lagoon, and that NGOs continue the CRAM monitoring of
wetland areas in the watershed. Enhanced monitoring is recoinmended ili some locations, particularly wet
weather monitoring and bioassessments. Analysis of this monitoring will help determine if water quality
objectives are being met and will help track progress from baseline (2007) conditions. Monitoriiig can
also help detennine if and where problem sources exists.
Watershed Indicators
The Watershed Council should work with partners to analyze results of the monitoring data as well as
other important tracking indicators: percent riparian habitat, percent impervious area, percent of new
development using LID. These watershed indicators should be used for evaluating plan performance.
Results should be incorporated into the Council's and local government's decision-making process for
adapting the management plan.
Watershed Council
The Watershed Council wiil provide a mechanism for routine watershed manageinent plan updates. It is
recoininended that the Council revisit the Plan every 5 to 10 years, considering recoirunendations on Plan
� revisions from the Watershed Partners Coinmittee and Technical Advisory Committee.
7.6 HOW THE PLAi� SUPPORTS REGIONAL REQUIREMENTS AND INITIATIVES
Many regional plans exist that relate closely to the Agua Hedionda WMP. Many of them were consulted
when developing the goals aud objectives for this WNIP and the recoininendations considered these
programs as collaborative opportunities. The discussion below shows the various programs that affect
watershed management in the region and how this plan is consistent with and integrates with them.
7.6.1 Local Urban Runoff Management Programs
7.6.1.1 Jurisdictional Urban Runoff Management Program (JURMPS)
RWQCB Order No. R9-2007-0001 (NPDES Pennit No. CAS0108758), Waste Discharge Requirements
fo�� Discharges of Urban Runoff from the Municipal Separate Stor�n Sewer Systems (MS4s) Draining the
Wate��sheds of the Counry of San Diego, the Incorporated Cities of San Diego County, the San Diego
Unified Port District, and the San Diego County Regional Airport Authority (2007 Order), describes
requirements for the control of pollutaut discharges from municipal stonn sewer systems (MS4s) within
Sau Diego County. The provisions of the 2007 Order require the development and implementation of
comprehensive Jurisdictional Urban Runoff Management Programs (JURIVII's).
The JURMP outlines actions that will be taken to control and reduce pollutants within the jurisdiction.
Most of the recommendations within this WMP support the objectives of the JURMPs, but likely the most
applicable are the recommended Citizen Stewardship/Public Outreach and the Stormwater BMP Retrofit
�������� � actions.
a r�rewre�
7-20
Agua Hedionda Watershed Management Plan — Final August 2008
�-° Also as a part of the NRMP are the SUSMP and Hydromodification requirements. The recommended
` new development site management actions support the SUSMP and Hydromodification requirements by
outlining techniques that are most effective for this specific watershed at accomplishing the goals of the
WMP and of these two programs.
7.6.1.2 Carlsbad Watershed Urban Runoff Management Program (WURMP)
The 2007 Order also requires that the Co-permittees within the Carlsbad Watershed collaborate in the
development and implementation of a watershed-based program that addresses urban runoff quality. The
rationale for this need is simple: urban runoff does not follow jurisdictionai boundaries and often travels
through many jurisdictions while flowing to receiving waters. Therefore, the actions of multiple
municipalities within a watershed can have a cuinulative impact upon shared receiving waters. The
mechanism that the 2007 Order uses to require watershed collaboration is the development of the
Watershed Urban Runoff Management Plan (WURMP). The goal of the Carlsbad WURMP is to reduce
the discharges of pollutants from the municipal separate starm sewer system (MS4) to the maximum
extent practicable (MEP) and prevent urban runoff discharges from the MS4 from causing ar contributing
to a violation of water quality standards. (CWLTRMP 2008).
The Agua Hedionda Watershed is within the Carlsbad Hydrologic Unit, which is designated a watershed
by the RWQCB for the purposed of the 2007 Order. In reality there are unique six watersheds within the
Carlsbad Hydrologic Unit. The Agua Hedionda WMP supports the goals and objectives of the Carlsbad
WLTRMP and its implementation can satisfy many of the requirements of the WURMP. Specifically the
Agua Hedionda WMP supports:
• Activity ID# CHU-WQA11: Land Acquisitions — This activity consists of supporting the
implementation the northern subarea plan. While this plan has yet to be approved by the County
�f of San Diego, lands have been and will continue to be acquired from willing sellers. As discussed
below, the MSCP has identified target preservation areas in the upper watershed.
• Activity ID #: CHU-WQEA1: Residential Irrigation Runoff Reduction Education — This activity
will focus on education of area residents related to water quality impacts of irrigation runoff.
• Activity ID #: CHU-WQEA4: LID and Watershed Planning for Coinmunity Planning and
Sponsor Groups — This activity involves educating local planning and sponsor groups throughout
the unincorporated County on low impact development (LID) and watershed planning principles,
practices, and requireinents.
• Proposed Public Participation Activities — The Carlsbad Watershed Co-permittees are responsible
for impleinenting a watershed-specific public participation mechanism within the watershed. The
mechanism encourages participation from other organizations within the watershed (such as other
agencies, private companies, enviromnental groups, etc.)
7.6.2 MHCP/MSCP and Open Space Plans (Some Jurisdictions)
The Multiple Habitat Conservation Program (MHCP) and Multiple Species Conservation Program
(MSCP) are comprehensive conservation planning processes that address the needs of multiple plant and
animal species in San Diego County. The MHCP goal is to conserve approximately 19,000 acres of
habitat and to contribute to the habitat preserve system for the protection of more than 80 rare, threatened,
or endangered species (SANDAG). Within the Agua Hedionda Watershed, the MHCP covers the
jurisdiction of Carlsbad, Vista, Oceanside and San Marcos. The acquisition priorities developed in this
WMP considered the MHCP as an indicator so that the areas identified herein overlap partially or fully
_%������������ with the MHCP priarities.
(� r�,R,►r�
t� 7-21
Agua Hedionda Watershed Management Plan — Final August 2008
The goal of the MSCP is to ensure the long-term survival of sensitive plant and animal species, protect
` the natural vegetation found throughout San Diego County, and provide for economic development of the
region through the development of large-scale open-space preserves created through acquisition of land
(County of San Diego). One technique used in the MSCP is the designation of pre-approved mitigation
areas (PAMAs}, which are areas identified with high biological value in which conservation will be
encouraged. PAMAs are proposed for the North County MSCP Subarea and are defined as habitat areas
that the Wildlife Agencies have pre-approved as meeting the criteria for the reduced mitigation
requirements as specified in the County's MSCP Plan. Early drafts of the North County MCSP Subarea
Plan identify a PAMA in the upper watershed which overlaps partially or fully the acquisition
recommendations of this WMP.
Local jurisdictions within the watershed have developed or will be developing local plans as part of the
MHCP and MSCP. The Carisbad Habitat Management Plan (HMP) is ah-eady in place, and the
Oceanside HMP is near completion. More details on the MHCP/MSCP and related plans are provided in
Appendix A.
7.6.3 Carlsbad Watershed Management Plan
The Carlsbad Watershed Management Plan includes �ve Plan Goals and twelve Plan Objectives that were
used as a foundation for developing the goals and objectives for this plan. Thus, this plan supports all of
the goals and objectives of the Carlsbad Watershed Managemeut Plan; however, it specifically helps meet
Action No. 3 Plan at the Watershed Level, but Analyze and Implement at the Sub-wate�^shed Level (note
that the reference to the watershed level in this context includes all of the Carlsbad Hydrologic Unit).
� 7.6.4 San Diego County IRWMP
� The Goals and objectives for the San Diego Integrated Water Management Plan (SDIRWMI') were also
used to develop the goals and objectives for this W1VIP. The specific goal that the Agua Hedionda WMP
supports is Goal No. 3 Protect and Enhance Water Quality. The specific objectives that are supported by
this plan include:
• Objective C- Further the scientific and technical foundation of water management,
• Objective F- Reduce the negative effects on waterways and watershed health caused by
hydromodification and flooding,
• Objective G- Effectively reduce sources of poliutants and enviromnental stressors, and
• Objective H- Protect, restore, and maintain habitat and open space
Also the following Water Management Strategies from the SDIRWMP are employed in the Agua
Hedionda WMP:
• Ecosystem restoration
• Ecosystem preseivation
• Environmental and habitat protection and improvement
• Wetlands enhancement and creation
• Poilution prevention
• Water quality protection and improvement
; • Urban runoff management
� ��
7-22
Agua Hedionda Watershed Management Plan — Final
• Watershed management and planning
• Stakeholder/Community Involvement
• Enhance scientific and technical knowledge
7.6.5 RWQCB Basin Plan, WMI, SWRCB NPS Strategic Plan,
California Ocean Plan
7.6.5.1 Watershed Management Initiative (WMI)
August 2008
The SWRCB and RWQCBs have developed a special initiative called the "Watershed Management
Initiative" to address issues related to watershed management, describe cunent regional efforts, and
establish an action plan to implement watershed management plans statewide. The two goals of the WMI
are to "preserve, enhance, and restore water resources while balancing economic and environmental
i»zpacts, " and "pronzote cooperative f�elationships and to improve support for the regulated community
and the public. " The stakeholder-driven development process used to develop the WMP and the
development of recommendations to preserve, enhance and restare the watershed supports the goals of the
WMI. This WMP supports and was driven by the RWQCB watershed management approach's seveu
guiding principles: geographic focus, comprehensive perspective, partnerships with stakeholders,
coordinated priority setting, best use of resources, improved decision making and iinproved ef�ciency.
7.6.5.2 RWQCB's Basin Plan
The RWQCB's Basin Plan is designed to preserve and enhance water quality and protect the beneficial
� uses of all regional waters. It designates existing and potential beneficial uses of groundwater and surface
�` - waters in the Region and establishes groundwater and surface water quality objectives to protect the
designated beneficial uses. Several water bodies in the watershed do not meet the Basin Plan objectives
and are considered impaired. This WMP supports the Basin Plan as it aims to reduce pollutants in the
watershed, thereby enhancing water quality and protecting the watershed's many beneficial uses.
7.6.5.3 SWRCB NPS Strategic Plan
The State Water Resources Control Board iinplements a Non-point Source (NPS) Pollution Program. The
NPS Pollution Plan goals include:
• Track, monitor, assess, and report NPS Program activities
• Target NPS Program activities
• Coordinate with public and private partners iu all aspects of the NPS Program
• Implement Management Measures (MM) and Management Practices (MP)
The 2003-2008 NPS Five-Year Implementation Plan objectives include:
• Promote the iinplementation of MMs and related practices by all levels of water quality managers
(federai, State, watershed groups and other stakeholders)
• Preserve water qualiry in waterbodies that are currently meeting California water quality
standards and protect them from future degradation for impacts of nonpoint source pollution
• Promote the implementation of MMs and use of MPs for the NPS components of TMDLs or in
CWA section 303(d) listed water bodies in order to improve water quality
(� rrrnw�
� --� 7-23
Agua Hedionda Watershed Management Plan — Fina!
August 2008
,
- • Promote better leverage of inter-agency and private entity resources for NPS Programs
The project meets the NPS Control Plan goals on a watershed level by implementing management
measures (MMs) to reduce and prevent NPS pollution from entering receiving waters. The WMP
recommends utilization of MMs from the Urban Category, Forestry Category, Hydromodifcation
Category, and Wetlands, Riparian Areas and Vegetated Treatment Systems Category of the State Water
Resources Control Board State of Califomia NPS Five-Year Implementation Plan (July 2003 through
June 2008). Recommendations for monitoring and tracking programs are integrated into the plan to
measure the effectiveness of the mauagement measures and the overall plan implementation. The
collaborative effort between local governinent, agency, academic and NGOs provides an interdisciplinaiy
approach to the WMP. Iinplementation of the Plan can also be used to also address TMDLs %r the
lagoon and creeks.
7.6.6 Agency Plans
7.6.6.1 California Department of Fish and Game
The mission of the Department of Fish and Game (DFG) is to manage California's diverse fish, wildlife,
and plant resources, and the habitats upon which they depend, for their ecological values and for their use
and enjoyment by the public. DFG's Strategic Plan is organized into four key theines; 1) Pubiic Service,
Outreach and Education, 3) Cooperative Approaches to Resource Stewardship and Use, 3) Manage
Wildlife from a Broad Habitat Perspective, and 4) Organizational Vitality. This WMP supports the first
three themes by establishing a forum for collaboration and stewardship, and presenting recommendations
that look at cumulative effects and a broad-based, ecosystem-wide approach to habitat preservation.
� DFG owns and inaintains the Agua Hedionda Lagoon Ecological Reserve along Agua Hedionda Creek
�.__ between the mouth and El Camino Real. Recommendations in the WMP include Stot7nwater Retrofit
sites that would protect the Reserve, and preservation and restoration opportunities that would enhance
and expand the open space around the Reserve. DFG also has designated a part of the lagoon as a marine
protected area. The Agua Hedionda Lagoon State Marine Reserve is adjacent to and waterside of the
Reserve and is a"no take" zone for fishing other than for restricted management purposes. The WMP
recommends projects that will reduce sedilnent from entering the lagoon that could impact the Marine
Reserve.
7.6.6.2 Southern California Wetland Recovery Project
The Southern California Wetlands Recovery Project (SCWRP) is a partnership of 18 state and federai
agencies working cooperatively with local government, business, and non-profit organizations to acquire,
restore, and enhance coastal wetlands in Southern California. The goal of SCWRP is to accelerate the
pace, extent, and effectiveness oi coastai wetlands restoration. The SCWRP's six regional goals are:
• Preserve and restore coastal wetland ecosystems.
• Preserve aud restore stream coi-�idors and wetland ecosystems in coastal watersheds.
• Recover native habitat and species diversity.
• Integrate wetlands recoveiy with other public objectives.
• Promote education and compatible access related to coastal wetlands and watersheds.
• Advance the science of wetiands restoration and management in Southern California.
SCWRP develops a Work Plan on a bia�ual basis that identifies priorities for Southern California
wetlands restoration alid enhancement, The Agua Hedionda WMP supports the goals of the SCWRP and
Q roTn,►r�a�
7-24
Agua Hedionda Watershed Management Plan — Final August 2008
X>-> specifically muitiple projects for acquisition and restoration recommended in this WMP support the Work
Plan Tier I and II proj ect priority list for the Stream Corridors/Riparian Areas.
7.6.6.3 SANDAG
SANDAG's TransNet Environmental Mitigation Program coordinates with local jurisdictions, wildlife
agencies, the building industry, and stakeholders to acquire open space for mitigation and to provide
funding for management and monitoring. The Agua Hedionda WIvIP identi�es acquisition and
restoration priorities through a comprehensive watershed approach that can be used to implement the
TransNet Environmental Mitigation Program.
It will be important in coming years to maintaining connections with these regional agencies to
continually show how the WMP support regional requirements and initiatives, both to build support for
the plan and to build win-win partnerships for project implementation.
{..
a r�rRwn�
7-25
Agua Hedionda Watershed Management Plan - Final August 2008
�.
(This page intentionally left blank.)
�
7-26
Agua Hedlonda Wate�shed Managemen[ P/an - Fina/ Aug✓s[ 2008
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