HomeMy WebLinkAboutCT 13-03; El Camino Rl widening Robertson Ranch; Robertson Ranch W.El Camino Rl widening; 2015-04-22RECORj) COPY
irutial
STORM WATER MANAGEMENT PLAN
For
EL CAMINO REAL WIDENING
RANCHO COSTERA
CDP 11-10
CT 13-03
SWMP 13-03
Revised: April 21, 2015
Revised: October 31, 2014
Revised: May 6,2014
Revised: December 10, 2013
Prepared: February 15, 2013
J.N. 10-1307-5
Prepared By:
O'DAY CONSULTANTS, INC.
2710 Loker Avenue West, Suite 100
Carlsbad, CA 92010-6609
(760) 931-7700
Date
X
George O'Daf; RCE 32014^xp. 12/31/16 / Date
?.n/.<r
FILE COPY
REVISION NOTED 10/31/2014:
BIORETENTION BMP'S 12,13 AND 17 HAVE BEEN
REMOVED AT THE CITY'S REQUEST. THE
BIORETENTION DEPTH IN THE NARROW MEDIAN
AREA POSED A DANGER TO THE CITY MAINTENANCE
CREWS. BIORETNETION BMP 11 HAS BEEN
INCREASED TO ACCOMMODATE THE LOST
TREATMENT AREA. THE PLANS, DWG 477-6, AND
ATTACHMENT 10 - SINGLE SHEET BMP EXHIBIT HAS
BEEN REVISED TO REFLECT THIS REVISION.
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TABLE OF CONTENTS
TABLE OF CONTENTS 2
1. PROJECT SETTING 4
2. APPLICABLE STORMWATER STANDARDS 5
2a. Storm Water Standards Questionnaire 5
2b. HMP Applicability Determination 5
3. IDENTIFY POLLUTANTS OF CONCERN 5
3a. Identify pollutants associated witli type of project/use 5
3b. Identify watershed, hydrologic unit basin and receiving waters....5
3c. List impaired water bodies 5
3d. Beneficial uses of receiving water 6
3e. Summarize primary pollutants of concem 7
4. SOURCE CONTROL MEASURES 7
4a. Description of site activities and potential sources of pollutants...7
4b. Stormwater Pollutant Sources and Source Controls 7
5. LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES...7
5a. Optimization of site layout 7
1) Setbacks of creeks, wetlands, and riparian habitats 7
2) Minimization of imperviousness 7
5b. Layout and use of pervious surfaces 8
5c. Dispersal of runoff from impervious areas to pervious areas 8
6. INTEGRATED MANAGEMENT PRACTICES (IMP's) 8
6a. Selection process for IMP's 8
6b. Sizing factors for IMP'S 8
6c. Geotechnical recommendation on soil inflitration rates 9
6d. Infiltration calculations 9
7. TREATMENT CONTROL BMP's 9
8. HYDROMODIFICATION 9
9. DOCUMENTATION OF STORMWATER DESIGN 9
9a. Hydrology maps 9
9b. BMP Sizing Calculator 9
9c. Tabulation 9
10. BMP FACILITY MAINTENANCE REQUIREMENTS 10
1 Oa. Ownership and responsibility of maintenance of BMP's 10
1 Ob. Summary of maintenance requirements 10
11. SWMP CERTIFICATION STATEMENTS 11
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Attachments:
1. Vicinity map
2. Storm Water Standards Questionnaire
3. Figure 2-1 HMP Applicability Determination
4. Table 2-1: Anticipated and Potential Pollutants
5. San Diego Region Hydrologic Boundary Map
6. 303(d) list for impaired water bodies
7. Table 2-3 Beneficial Uses of Coastal Waters
8. Stormwater Pollutant Sources and Source Control Checklist
9. Figure 2-2 Decision Matrix
10. Single Sheet BMP exhibit
11. BMP Calculator Output
12. Geosoils Recommendation Letter for Bioretention Areas
13. Downstream Channel Analysis by Wayne Chang
14. Stormwater Treatment basins maintenance cost
G:\l01307\SWMP\ECR-Widening\IP-Submittal #5\SWMP.doc
1. PROJECT SETTING
This Storm Water Management Plan was prepared to support the Widening of El Camino Real
between Cannon Road and Tamarack Avenue, in the City of Carlsbad. See Attachment 1 for
Vicinity Map of the site. Storm water run-off from the site is tributary to Agua Hedionda Creek.
As part ofthe Future Development for Rancho Costera located to the north, CT 11-01, also
known as Robertson Ranch West Village, the City of Carlsbad has required the developer to
improve El Camino Real. The improvements consist of widening to a right-of-way width of 126
feet, with appropriate turn pockets for the future development as well as a median in the center of
the street. This improvement encompasses the entire length of the northerly side of El Camino
Real between Cannon Road and Tamarack Avenue. The improvements on the southerly side of
El Camino Real are limited to two portions: one portion from just west of Crestview Drive to just
east of Lisa Street and another portion west of the projection of Julie Place to just east of Kelly
Drive. The existing street is improved to a width of 40 feet from the centeriine (except where
shown on the south side of the street).
Beginning from the intersection of Cannon Road heading west, existing El Camino Real drains
to a low point. An existing 8'x8' reinforced box culvert conveys storm water from the north to
the south side of the street. Heading westerly on El Camino Real towards Crestview Drive, an
existing 24" storm drain conveys storm water from the north side to the south side of El Camino
Real and outlets east of Crestview Drive. A curb inlet and storm drain is proposed west of the
Crestview Drive intersection to prevent storm water runoff from crossing Crestview Dri\'e as
occurs under existing conditions. Continuing westerly, there is an existing 48" storm drain near
the projection of Julie Place. 58.80 acres of land to the north drains to this existing 48" storm
drain and is conveyed to a channel within land owned by Hoffman (APN 207-101-27, 28, and
29). Currently storm water from a portion of El Camino Estates runs onto El Camino Real.
That storm water combined with storm water from the high point at El Camino Real drain to
property owned by Marja Acres, LLC (APN 207-101-24 and 25). To alleviate runoff to property
owned by Hoffman and Marja Acres, a series of storm drains and curb inlets are proposed. This
storm drain will serve as Drainage Project BFA of the City of Carlsbad Drainage Master Plan
dated July 3, 2008 prepared by Brown and Caldwell. Continuing westerly, 11.5 acres of land to
the north drains into El Camino Real. Since the street is superelevated at this location, both sides
of the street drain to the low point to the north, west of Kelly Drive combining with storm water
from the Tamarack intersection. The storm water is conveyed to the south via an existing double
8'x4' reinforced culvert box. The proposed storm drain will alleviate impacts to the sensitive
wetland area to the north by conveying storm water to the south side of El Camino Real.
There are several opportunities and constraints for storm water flow control and treatment on this
site. Constraints include steep slopes and the presence of Soil Type D. Also, the areas of the
street that are superelevated as well as the minimal room between the curb and the right-of-way
present a challenge for storm water treatment. Opportunities include the use of pervious pavers
or pervious concrete in the median, and bioretention with impermeable liners (flow-through
planters).
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2. APPLICABLE STORMWATER STANDARDS
2a. Storm Water Standards Questionnaire
Per the Storm Water Standards Questionnaire (SWSQ), this project meets PRIORITY
DEVELOPMENT PROJECT (PDP) requirements and must comply with additional stormwater
criteria per the SUSMP. (See Attachment 2 for completed SWSQ)
2b. HMP Applicability Determination
Per Figure 2-1 of the SUSMP, Hydromodification controls are required. (See Attachment 3 for
Figure 2-1 HMP Applicability Determination.) It was determined that field investigations would
not be conducted pursuant to the SCCWRP channel screening tools. Therefore the site must
mitigate peak flows and durations based on a pre-project condition lower flow threshold of
0.1Q2.
3. IDENTIFY POLLUTANTS OF CONCERN
3a. Identify pollutants associated with type of project/use
Per Table 2-1 of the SUSMP (see Attachment 4), the pollutants anticipated for Streets, Highways
& Freeways are:
Sediment
Nutrients (potentially)
Heavy Metals
Organic Compounds
Trash & Debris
Oxygen Demanding Substances (due to on-site landscaping)
Oil & Grease
Bacteria & Viruses (potentially)
Pesticides
3b. Identify watershed, hydrologic unit basin and receiving waters
The project is located in the Los Monos Hydrologic Subarea (904.31) of the Agua Hedionda
Watershed in the Carlsbad Hydrologic Unit in the San Diego Region (Attachment 5). Under both
existing and proposed conditions, storm runoff from the El Camino Real Widening is eventually
conveyed to Agua Hedionda Creek, and then continues westerly to Agua Hedionda Lagoon.
3c. List impaired water bodies
According to the Califomia 2006 303(d) list published by the RWQCB (Attachment 6), Agua
Hedionda Creek and Agua Hedionda Lagoon are impaired water bodies associated with the
stormwater discharge from this project. Agua Hedionda Creek has impairment for manganese,
selenium, sulfates, and Total Dissolved Solids. Agua Hedionda Lagoon has impairment for
G:\101307\SWMP\ECR-Widening\IP-Subniittal tt 4 14103 USWMP.doc^
Indicator bacteria and sedimentation/siltation. Sites tributary to Clean Water Act Section 303(d)
water bodies require additional BMP implementation.
3d. Beneficial uses of receiving water
The beneficial uses for the hydrologic unit are included in Attachment 7, and the definitions are
listed below. This information comes from the Water Quality Control Plan for the San Diego
Basin.
IND - Industrial Service Supply: Includes uses of water for industrial activities that do not
depend primarily on water quality including, but not limited to, mining, cooling water supply,
hydraulic conveyance, gravel washing, fire protection, or oil-well repressurization.
NAV - Navigation: Uses of water for shipping, travel, or other transportation by private,
military, or commercial vessels.
REC 1 -Contract Recreation: Includes uses of water for recreational activities involving body
contact with water, where ingestion of water is reasonably possible. These uses include, but are
not limited to, swimming, wading, water-skiing, skin and SCUBA diving, surfing, white water
activities, fishing, or use of natural hot springs.
REC 2 -Non-Contact Recreation: Includes the uses of water for recreational activities
involving proximity to water, but not normally involving body contact with water, where
ingestion of water is reasonably possible. These include, but are not limited to, picnicking,
sunbathing, hiking, beachcombing, camping, boating, tide pool and marine life study, hunting,
sightseeing, or aesthetic enjoyment in conjunction with the above activities.
COMM - Commercial and Sport Fishing: Includes the uses of water for commercial or
recreational collection of fish, shellfish, or other organisms including, but not limited to, uses
involving organisms intended for human consumption or bait purposes.
BIOL - Preservation of Areas of Special Biological Significance
WARM - Warm Freshwater Habitat: Includes uses of water that support warm water
ecosystems including, but not limited to, preservation or enhancement of aquatic habitats,
vegetation, fish, or wildlife, including invertebrates.
EST - Estuarine Habitat: Includes the uses of water that support estuarine ecosystems
including, but not limited to, preservation or enhancement of estuarine habitats, vegetation, fish,
or wildlife (e.g., estuarine mammals, waterfowl, shorebirds).
MAR -Marine Habitat: Includes uses of water that support marine ecosystems including, but
not limited to, preservation or enhancement or marine habitats, vegetation such as kelp, fish,
shellfish, or wildlife (e.g., marine mammals, shorebirds).
WILD -Wildlife Habitat: Includes uses of water that support terrestrial ecosystems including
but not limited to, preservation and enhancement of terrestrial habitats, vegetation, wildlife, (e.g..
mammals, birds, reptiles, amphibians, invertebrates), or wildlife water food and sources.
RARE - Rare, Threatened, or Endangered Species: Includes uses of water that support
habitats necessary, at least in part, for the survival and successfiil maintenance of plant or animal
species established under state or federal law as rare, threatened or endangered.
AQUA - Aquaculture: Includes the use of water for aquaculture or mariculture operations
including, but not limited to, propagation, cultivation, maintenance, or harvesting of aquatic
plants and animals for human consumption or bait purposes.
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MIGR-Migration of Aquatic Organisms: Includes uses of water that support habitats
necessary for migration, acclimatization between fresh and salt water, or other temporary
activities by aquatic organisms, such as anadromous fish.
SHELL - Shellfish Harvesting: Includes uses of water that support habitats suitable or the
collection of filter-feeding shellfish (e.g., clams, oysters, and mussels) for human consumption,
commercial, or sport purposes.
3e. Summarize primary pollutants of concern
The primary pollutants of concem for this project are Sediment, Nutrients, Trash & Debris,
Oxygen Demanding Substances, Oil &. Grease, Bacteria a& Vimses, and Pesticides. The
extensive use of bioretention facilities throughout the site should be a highly effective method of
treating Coarse Sediment and Trash, and Pollutants that tend to associate with fine particles
during treatment. Bioretention facilities also show medium effectiveness for treatment of
Pollutants that tend to be dissolved following treatment.
4. SOURCE CONTROL MEASURES
4a. Description of site activities and potential sources of pollutants
Potential sources of pollutants on the project site include:
On-site storm drain inlets
Landscape/Outdoor Pesticide Use
Sidewalks
4b. Stormwater Pollutant Sources and Source Controls
See attachment 8 for Stormwater Pollutant Sources and Source Control Checklist
5. LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES
5a. Optimization of site layout
1) Setbacks of creeks, wetlands, and riparian habitats
Minimize impacts to wetlands, or riparian habitats on the site near the low points west of
Cannon Road and east of Kelly Drive.
2) Minimization of imperviousness
In order to minimize imperviousness, we will utilize porous pavers or pervious concrete
in the median as well as landscaped median pockets per the City of Carlsbad Landscape
Manual.
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6c. Geotechnical recommendation on soil inflitration rates
Inflitration rates for Type 'D' soil are low, an underdrain and impermeable liner will be utilized
in bioretention areas (flow-through planters). See Attachment 12 for geotechnical
recommendations for bioretention areas.
6d. Inflitration calculations
See Attachment 12 for infiltration rate information.
Self-retaining areas were not utilized on this site, as soil infiltration rates were anticipated to be
low.
7. TREATMENT CONTROL BMP's
Lined bioretention areas (flow-through planters) were sized for both treatment and
hydromodification.
8. HYDROMODIFICATION
Lined bioretention areas (flow-through planters) were sized for both treatment and
hydromodification.
9. DOCUMENTATION OF STORMWATER DESIGN
9a. Hydrology maps
Attachment 10 depicts the 1) Existing Impervious Surface on El Camino Real 2) The proposed
Impervious Surface 3) Pervious Pavement and Landscaping proposed on Site and 4) the Self-
Treating Areas.
9b. BMP Sizing Calculator
Output from the BMP Sizing Calculator is included in Attachment 11.
9c. Tabulation
See Output from the BMP Sizing Calculator included in Attachment 11.
G:\101307\SWMP\ECR-Widening\IP-Submittal # 4 141031\SWMP.doc9
10. BMP FACILITY MAINTENANCE REQUIREMENTS
10a. Ownership and responsibilify of maintenance of BMP's
The Owner and Developer will be responsible for the maintenance of treatment facilities.
Ongoing maintenance will be assured by executing a Permanent Stormwater Quality BMP
Maintenance Agreement that "runs with the land." Once HOA established, HOA responsible for
maintenance, repairs, etc.
Maintenance Contact:
Name
Company
Address
Phone
10b. Summary of maintenance requirements
Bioretention facilities remove pollutants primarily by filtering mnoff slowly through aerobic,
biologically active soil. Routine maintenance is needed to ensure that flow is unobstructed, that
erosion is prevented, and that soils are held together by plant roots and are biologically active.
Typical maintenance consists ofthe following:
• Inspect inlets for channels, exposure of soils, or other evidence of erosion. Clear
any obstmctions and remove any accumulation of sediment. Examine rock or
other material used as a splash pad and replenish if necessary.
• Inspect outlets for erosion or plugging.
• Inspect side slopes for evidence of instability or erosion and correct as necessary.
• Observe the surface of bioretention facility soil for uniform percolation
throughout. If portions of the bioretention facility do not drain within 24 hours
after the end of a storm, the soil should be tilled and replanted. Remove any
debris or accumulations of sediment.
• Confirm that check dams and flow spreaders are in place and level and that
rivulets and channelization are effectively prevented.
• Examine the vegetation to ensure that it is healthy and dense enough to provide
flitering and to protect soils from erosion. Replenish mulch as necessary, remove
fallen leaves and debris, pmne large shrubs or trees, and mow turf areas. When
mowing, remove no more than 1/3 height of grasses. Confirm that irrigation is
adequate and not excessive and that sprays do not directly enter overflow grates.
Replace dead plants and remove noxious and invasive vegetation.
• Abate any potential vectors by filling holes in the ground in and around the
bioretention facility and by insuring that there are no areas where water stands
G:\101307\SWMP\ECR-Widening\IP-Submittal # 4 14103 l\SWMP,dojQ
longer than 48 hours following a storm. If mosquito larvae are present and
persistent, contact the San Diego County Vector Control Program for information
and advice. Mosquito larvicides should be applied only when absolutely
necessary and then only by a licensed individual or contractor.
11 SWMP CERTIFICATION STATEMENTS
Ila. Preparer's statement
The selection, sizing, and preliminary design of stormwater treatment and other control measures
m this plan meet the requirements of Regional Quality Control Board Order R9-2007-0001 and
subsequent amendments.
George Q/Day, RCE 32014^p. 12/31/14 '^^^'^ O^^te
lib. Owner's statement
The selection, sizing, and preliminary design of stormwater treatment and other control measures
m this plan meet the requirements of Regional Quality Control Board Order R9-2007-0001 and
subsequent amendments.
^oll Brothers Date
G:\101307\SWMP\ECR-Widening\IP-Subinittal #2\SWMP,doc |}
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CITY OF OCEANSIDE
HIGHWAYi
SITE
CITY OF VISTA
PACIFIC
OCEAN
CITY OF
SAN MARCOS
CITY OF ENCINITAS
VICINITY MAP
NO SCALE
^ CITY OF
CARLSBAD
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Develooment Services
Land Oevelopment Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
INSTRUCTIONS:
To address post-development pollutants that may be generated from development projects, the City requires that new
development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management
Practices (BMP's) into the project design per the City's Standard Urban Stormwater Management Plan (SUSMP). To
view the SUSMP. refer to the Engineering Standards (Volume 4. Chapter 2) at www catisbadca.Qov/standards.
Initially this questionnaire must be completed by the appHcant in advance of submitting for a development application
(subdivision, discretionary permits and/or constmction permits). The results of the questionnaire determine the level of
stomi water'standards that must be applied to a proposed development or redevelopment prpject. Depending on the
outcome, your project wiil either be subject to 'Standard Stormwater Requirements' or be subject to additional criteria
called Priority Deveiopment Project Requirements'. Many aspects of project site design are dependent upon the
storm water standards applied to a project.
Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts.
City staff has responsibility for making the final assessment after submission of the development application. If staff
determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than
initially assessed by you. this will result in the retum of the development application as Incomplete. In this case, please
make the changes to the questionnaire and resubmit to the City.
If you are unsure aboul the meaning of a question or need help in determining how to respond to one or more of the
questions, please seek assistance from Land Development Engineering staff.
A separate completed and signed questkjnnaire must be submitted for each new development applteation submlsston.
Only one completed and signed questtonnaire is required when multiple development appltoattons for the same project
are submitted concurrenUy. In addition to this questtonnaire. you must also complete, sign and submit a Project Threat
Assessment Form with constnjction permits for the project
P/ease sfarf by completing Section 1 and follow the instructions. When completed, sign the fomi at the end and sutxnit
tt)ia witi) your application to the city.
SECTION 1 NEW DEVELOPMEMT
DOM your project nw^t on« or mor* of th« folfowing criterta: YES NO
1 ^tff'rw MubdMatona of 10 ar merm dwHIna unHa. Examoles: single family home*, multi-family hornet,
condominium and apartmenta _—.—_ X
9 ntunmmrcM - D/Mtar tfian 1-acn. Anv development other than heavy Industry or residential. Examples: hospitals;
laboratoriee and other medical facilities; educational Institutions; recreational tacilities; municipal facilities; commercial
nurseries; multi-apartment buildings; car wash fecilities; minl-malls and other business complexes; shopping mafls;
hotels- ofiice buiWings: public warehouses; automotive dealerships; airfields; and other nght Industrial facilities.
1 i^w,, inHu»trM 1 /ndiistn* nfmtmr than f aer«: Examoles: manufactunng plants, food processing plants, metal
working faciUties, prInUng plants, and fleet storage areas (bus, truck, etc.). K
4 AutanmtNm noair thoo. A facility categorized in any one of Standard Industrial Classification (SIC) codes 5013,
5014, 5541. 7532-7534, and 7536-7539 K
s RmttaunntM. Anv facility that sells prepared foods and drinks Ibr consumption, including stationary lunch counters
and refreshment stands selling prepared foods and drinks for immediate consumpfion (SIC code 5812), where the
land area for development Is greater than 5,000 square feet. Restaurants where land development is less than 5,000
square feet shall meet all SUSMP requiremonts except fdr structural treatment BMP and numeric sizing criteria
requirements and hvdronwdificafion requirements.
K
E-34 Page 1 of 3 REV 1/14/11
\^ CITV OF
CARLSBAD
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Oevelopment Seruiri>c
Land Oevelopment Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
twentv-five percent (2S%1 or gmatlf. >*^8fB the devetopment wiH grade on any natural slope that Is
^'^To^"sA!!!^J^7rJ^]'!!^ Z Z '^'T*^ ^^^"'^ >° °^ dischargi,^
ESA). which either creates 2.500 ^anfeatV^^^^^ ^^•^"O *«'»™ within tfi
the area of ImoenHousneu <^Tn^Z y|^?:r.^JTPy^ °"' « P«>Posed project site or Increase
^tMlgiatA«aof6,(X)0squa^iKor3^w^^^^^
runoff ewormore.or with 15 or more pari<ing spaces, and potentially exposed to urban
?i%a7fcSl^S;gLK^cl£^^^ " '> "°° -"l"^^ fe" or graatar used fbr th.
^Hff gw/fpf sen.^ more than 100 vehk:les per day and greater than S.OOO souare faS
X
bodlM
•mandmanla):
oqufvaJant
not commnfll^l wilh to* from .4««rttanA * "^'^'"•'^ »'"h. «,h^ ^
INSTRUCTIONS:
Secttan 1 RssuW^;
If you answenKi NO to AU of th, question, abov p,,.^ ^ , ^ ^
E-34 Page 2 of 3 REV 1/14/11
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\^ CITY O F
CARLSBAD
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Development Servir^^
Land Oevetopment Engineering
1635 Faraday Avenue
760 602-2750
www.carlsbadca.gov
SECTION 2 SIONIFICAWT REOevaOPMEWT
INSTRUCTIONS: Complete the questions below regarding your project
YES
liNU 1 KUtnoNS: II^NO, pluMpiocMtoqunto,2
INSFRUCTIONS: If you answered NO. then proceed to questton 4
NO
existing impen/ious surfaces indudes any acUviSftrt k^^^of^^.*^:^^ I"'" R«placement of
r^"^- undertvino soa riuriJn,.JZLlZ: "'^P^'^ routina maintenance whera Impervtoue material(s) ara
INSTRUCTIONS^ If vou answarsd VES urui ABB ' 1— ——————
PROJECT requiremejS. Please^ LkVmaeta iSmS^^Zl^^K'^Ji'^ '"^^ ^ '''"OWTT DEVELOPMENT ' "
SUSMP to find out. SUSMP requiremen^ap^S S?p'2«°ei:X^1Je\'n"^^^^^^ ^"C^^Z^e^^^
for deflnition see Footnote 4 on page 2 " ~~ —
SECTION 3
a
My project meets PRiORJTY OEVELOPMEMT Pao lerr fanai
per the SUSMP and I understend I muslprwLe a S^^ ««"P^ ^ addittonal stormwater crifari-
Applicant Infomiation and Slc^tur* Box
Assessors Parcel Numbaf(8):
AppHcant TlHe:
Date:
r7w au «r Ciy UM cM^
YES NO
E-34 Page 3 of 3 REV 1/14/11
SECTION 2: IDENTIFY POLLUTANTS, BMP SIZING AND SELECTION
TABLE 2-1. ANTICIPATED AND POTENTIAL PoUulants Cicnemtcd by Lind L'sc T\-pe,
General Po lutant Categories
Priority Project
Cuegories Sediment Nutrients
t leavy
Metals
Organic
Compounds
Trash
&
Debris
Oxygen
Demanding
Substances
Oil&
Grease
Bacteria
&
Viruses Pesdcides
Det.ached
Residenlial
Development
X X X X X X X
.Attached
Residendal
I^evelopment
X X X P(l) P(2) P X
Commercial
Development
>one acre
P(l) P(l) X P(2) X P(.S) X P(3) P(5)
1 leav)- Industry-X X X X X X
.Vutomotive
Repiiir Shops X X(4)(5) X X
Restaurants X X X X P(l)
Hillside
Development
>5,0l)0 ft2
X X X X X X
Parking Lots P(l) P(l) X X P(l) X P(l)
Ret.ail Gasoline
Oullets X X X X X
Streets,
Highways &
Preeways
X P(!) X X(4) X P(5) X X P(l)
\ - anticipated
P = p<3tential
(1) .'\ potential pollutant it landscaping exists on-site,
(2) ,\ potential pollutant ifthe project includes uncovered parking areas,
(3) ,\ potential pollutant it'land use involves lood or animal waste products.
(4) Including petroleum hydrocarbons,
(5) Including solvents.
23 City of Carlsbad SUSIVIP - January 14, 2011
SECTION 2: IDENTIFY POLLUTANTS. BMP SIZING AND SELECTION
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Disiipaion Syattn
Erid of Dtctsion Matrix [
14. Hydramodificjtion Controlt Rftquirtd
Ooto Figura 7.tot D«citionMatrix
FIGURE 2-1. HMP Applicabilit\' Determinarinn*
'refer to cxp.inded H.\IP exempdon criteria helinv for jusnfications required (jn each node
30 City of Carlsbad SUSMP - January 14, 2011
2006 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENTS REQUIRING TMDLS
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SrIciiiuiii
Source I iiknon n
7 Miles 20 I'J
Sulfates
Source l'nknown
7 Miles 2019
l olal Dissolved Solids
Souree I nkiiOHn
7 Miles 2(119
K A^UH Hedionda l.!t)>ooii 90431000
Indicator bacteria
I rhan RunolT/Storni Sewers
linkuown .Nonpoint Source
I nknown point source
(>.,S .Veres 2U06
Sediiiu-Ilia tio n/Sillation
,\oupoiul/l'oinl Source
(l.S Acres 2019
R Aliso f reek 90113000
Nonpoint/Hoint Source
Iiidlealiir barleria [i> Miles 2005
/hi\ li.Miiij^ l<:r iiidicaior bcicli.-rui upplu's In ilu-. l/i.so ( ivek iiiuin.ileiii anil nil ihc ituiinr inhuhmc.s af. lli.vi Creek vliU li
ure \iili>ln(r i reek. Wood Canyon. .Ill.so llill.s i'anynir I hiny I'oik. anil Enyli.'ili ( 'ainoii
I rban RunolT/Slorin .Sewers
l.nknowii poiiil souree
Nonpoiiil/Puint Souree
I'hospliurus |.; 2019
/I'l/v 'i (./i,k' llll iiho.i/iliorm ii/i/jlie.s lo llh ili\o i /n A iiuiiiisieni ami all lite major inhni.u .,/ < reek wliicli are
')</;'//,,.. ( reck. W ood (. 'anyim, .Mi.sii Ililh i \ii,\ ,<ii i Kan iork. and Knglisli Caiivuii
I rbaii RiMiulT'Siiifm .Sewers
I iiknowii Nonpoini Suuree
I nknowii pninr source
Table 2-3. BENEFICIAL USES OF COASTAL WATERS
BENEFICIAL USE
Coastal Waters
HycJrologic
Unit Basin
Number
1
IM
D
N
A
V
R
E
C
1
R
E
C
2
C
0
M
M
B
1
0
L
E
S
T
W
1
L
D
R
A
R
E
M
A
R
A
Q
U
A
M
1
G
R
S
P
w
N
W
A
R
M
S
H
E
L
L
Pacific Ocean • • • • • • • « •
Dana Point Harbor • • • • • •
Del Mar Boat Basin • • • • • • •
Mission Bay • • • • • •
Oceansitde Harbor • • • • • •
San Diego Bay ' • • • • • • • • •
Coastal Lagoons
Tijuana River Estuary 11.11 • • • • • •
Mouth of San Diego River 7.11 • • • • • •
Famosa Slough and Channel 7.11 • • • • • •
Los Penasquitos Lagoon ' 6.10 • • • • •
San Dieguito Lagoon 5.11 • • • • •
Batiquitos Lagoon 4.51 • • • • •
San Elljo Lagoon 4.61 • • • • • •
Agua Hedionda Lagoon 4.31 • • • • • • • • • • •
' InclucJes the tidal prisms of the Otay and Sweetwater Rivers.
' Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited,
se^ilr'-'(r",'"rT ' n"°" " '^^^'S'^^'^'^ '"^P«"«d water body for dissolved copper pursuant to Clean Water Ac,
• Existtnc] Bi;neficial Use
T.ibl,
bENi '
Table 2-3. BENEFICIAL USES OF COASTAL WATERS
Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited.
• Existing Beneficial Use
O Potential Beneficial Use
Coastal Waters
Hytdrologic
Unit Basin
Number
1
N
D
N
A
V
R
E
C
1
R
E
C
2
C
0
M
M
B
1
0
L
E
S
T
w
1
L
D
R
A
R
E
M
A
R
A
Q
U
A
M
1
G
R
S
P
w
N
W
A
R
M
S
H
E
L
Coastal Lagoons - continued L
Buena Vista Lagoon '
Loma Alta Slough
4,21
4.10
• • • O • • • •
Mouth of San Luis Rey River 3.1 1
• •
• Santa Margarita Lagoon 2.11 • • • •
Aliso Creek Mouth 1,13 • •
San Juan Creek Mouth 1.27 • • • San Mateo Creek Mouth 1,40 • • • •
San Onofre Creek Mouth — _ 1.51 • • • • • • •
Table .• •
BtNI-.i ,
stormwater Pollutant Sources and Source Control Checklist
How to Use this Checklist:
1. Revi.,. <:„1„„,„ 1 „d „e„„f, .hid, of ,K,c p,„e„,„l of s,„™„ p„„„,„, ,„ p„,„,
2. Review 0,lum„ 2 ami i„c„T«„„e all of the correspondine applicable BMP, in you, SUSMP Drawing,.
conditiotis or situations that required omitting BMPs or substituting altematives. accompanying narrative, and explain any special
IF THESE SOURCES
WILL BE ON THE
PROJECT SITE ...
Potential Sources of
Runoff Pollutants
03^ A. On-site storm drain
inlets
... THEN YOUR PROJECT SHOULD INCLUDE THESE SOURCE CONTROL BMPs
Pemianent Controls—Show on
SUSMP Drawings
Locations of inlets.
Permanent Controls—List in SWMP
Table and Narrative
(H^ Mark all inlets with the words "No
Dumping! Flows to Bay" or similar.
4
Operational BMPs—Inciude in
.SWMPJjb^ Narrative
Maintain and periodically repaint or
replace inlet markings.
O^Provide stormwater pollution
prevention information to new site
owners, lessees, or operators.
CO-^ee applicable operational BMPs in
Fact Sheet SC-44, "Drainage System
Maintenance," in the CASQA
Stormwater Quality Handbooks at
www.cahmphandbonks-«-nm
Include the following in lease
agreements: "Tenant shall not allow
anyone to discharge anything to
storm drains or to store or deposit
materials so as to create a potential
discharge to storm drains."
Page 1 of 9
B. Interior floor drains
and elevator shaft sump
pumps
• C. Interior parking
garages
• Dl. Need for future
indoor & structural pest
control
State that interior floor drains and
elevator shaft sump pumps will be
plumbed to sanitary sewer.
State that parking garage floor drains
will be plumbed to the sanitaiy sewer.
Note building design features that
discourage entty of pests.
• Inspect and maintain drains to
prevent blockages and overflow.
• Inspect and maintain drains to
prevent blockages and overflow.
• Provide Integrated Pest Management
information to owners, lessees, and
operators.
D2. Landscape/
Outdoor Pesticide Use
Q'"^ Show locations of native trees or
areas of shrubs and ground cover to
be undisturbed and retained.
Show self-retaining landscape
areas, if any.
If a PDP, show stormwater
treatment facilities.
• E. Pools, spas, ponds,
decorative fountains,
and other water
features.
Show location of water feature and
a sanitary sewer cleanout in an
accessible area within 10 feet.
State that final landscape plans will
accomplish all of the follovving.
13^ Preserve existing native trees, shrubs,
and ground cover to the maximum
extent possible.
Design landscaping to minimize
irrigation and runoff, to promote
surface infiltration where appropriate,
and to minimize the use of fertilizers
and pesticides that can contribute to
stormwater pollution.
Where landscaped areas are used to
retain or detain stormwater, specily
plants that are tolerant of saturated
soil conditions.
ST Consider using pest-resistant plants,
especially adjacent to hardscape.
To insure successful establishment,
select plants appropriate to site soils,
slopes, climate, siui, wind, rain, land
use, air movement, ecological
consistency, and plant interactions.
If the local municipality requires pools
to be plumbed to the sanitary sewer,
place a note on the plans and state in
the narrative that this connection wiU
be made according to local
requirements.
Maintain landscaping using
minimum or no pesticides.
See applicable operational BMPs in
Fact Sheet SC-41, "Building and
Grounds Maintenance," in the
CASQA Stormwater Quality
Handbooks at
^^'^\•w.cabmphandbooks.cnm
Provide IPM information to new
owners, lessees and operators.
See applicable operational BMPs in
Fact Sheet SC-72, "Fountain and
Pool Maintenance," in the CASQA
Stormwater Quality Handbooks at
w-ww.cabmphandbooks.com
Page 2 of 9
• F. Food 1 • For restaurants, grocery stores, and
other food service operations, show
location (indoors or in a covered
area outdoors) of a floor sink or
other area for cleaning floor mats,
containers, and equipment.
• On the drawing, show a note that
this drain will be connected to a
grease interceptor before
discharging to the sanitary sewer.
Show where site refuse and
recycled materials will be handled
and stored for pickup. See city
standard drawing GS-16.
If dumpsters or other receptacles
• are outdoors, show how the
designated area will be covered,
graded, and paved to prevent run-
on and show locations of berms to
prevent runoif from the area.
Any drains from dumpsters,
• compactors, and tallow bin areas
shaU be connected to a grease
removal device before discharge to
sanitary sewer.
Show process area.
Describe the location and features of
the designated cleaning area.
Describe the items to be cleaned in
this facility and how it has been sized
to insure that the largest items can be
accommodated.
State how site refuse will be handled
and provide supporting detail to what
is shown on plans.
State that signs wdll bc posted on or
near dumpsters with the words "Do
not dump hazardous materials here"
or similar.
If industrial processes are to be
located on site, state: "All process
activities to be performed indoors. No
processes to drain to exterior or to
storm drain system."
State how the following will be
implemented:
Provide adequate number of
receptacles. Inspect receptacles
regularly; repair or replace leaky
receptacles. Keep receptacles
covered. Prohibit/prevent dumping
of liquid or hazardous wastes. Post
"no hazardous materials" signs.
Inspect and pick up litter daily and
clean up spills immediately. Keep
spill control materials available on-
site. See Fact Sheet SC-34, "Waste
Handling and Disposal" in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandhf^nlfQ r^tn
See Fact Sheet SC-10, "Non-
Stormwater Discharges" in the
CASQA Stormwater Quality
Handbooks at
www.cahmphandhook.s.rnm
Page 3 of 9
• i. Outdoor storage of
equipment or materials.
(See rows J and K for
source control
measures for vehicle
cleaning, repair, and
maintenance.)
Ql Show any outdoor storage areas,
including how materials will be
covered. Show how areas will be
graded and bermed to prevent run-
on or run-off from area.
• Storage of non-hazardous liquids
shall be covered by a roof and/or
drain to thc sanitary sewer system,
and be contained by berms, dikes,
liners, or vaults.
• Storage of hazardous materials and
wastes must be in compliance vnth
the local hazardous materials
ordinance and a Hazardous
Materials Management Plan for the
site.
Include a detailed description of
materials to be stored, storage areas,
and structural features to prevent
pollutants from entering storm drains.
Where appropriate, reference
documentation of compliance with the
requirements of local Hazardous
Materials Programs for:
• Hazardous Waste Generation
• Hazardous Materials Release
Response and Inventory
• Califomia Accidental Release
(CalARP)
• Aboveground Storage Tank
• Uniform Fire Code Article 80
Section 103(b) & (c) 1991
" Underground Storage Tank
• See the Fact Sheets SC-31, "Outdoor
Liquid Container Storage" and SC-
33, "Outdoor Storage of Raw
Materials " in the CASQA
Stormwater Quality Handbooks at
www.cabmphandbooks.cnm
Page 4 of 9
J. Vehicle and
Equipment Cleaning Show on drawings as appropriate:
(1) Commercial/industrial facilities
having vehicle /equipment
cleaning needs shall either provide
a covered, bermed area for washing
activities or discourage
vehicle/equipment washitig by
removing hose bibs and installing
signs prohibiting such uses.
(2) Multi-dwelling complexes shall
have a paved, bermed, and covered
car wash area (unless car washing
is prohibited on-site and hoses are
provided with an automatic shut-
off to discourage such use).
(3) Washing areas for cars, vehicles,
and equipment shall be paved,
designed to prevent run-on to or
runoff from the area, and plumbed
to drain to the sanitary sewer.
(4) Commercial car wash facilides
shall be designed such that no
runoff from the facility is
discharged to the storm drain
system. Wastewater from the
facility shall discharge to the
sanitaty sewer, or a wastewater
reclamation system shall be
installed.
• If a car wash area is not provided,
describe measures taken to discourage
on-site car washing and explain how
these will be enforced.
Describe operational measures to
implement the following (if
applicable):
• Washwater from vehicle and
equipment washing operations shall
not be discharged to the storm drain
system.
• Car dealerships and similar may
rinse cars with water only.
• See Fact Sheet SC-21, "Vehicle and
Equipment Cleaning," in the CASQA
Stormwater Quality Handbooks at
w-vvw.cabmphandbooks.cnm
Page 5 of 9
K. Vehicle/Equipment
Repair and
Maintenance
• Accommodate all vehicle
equipment repair and maintenance
indoors. Or designate an outdoor
work area and design the area to
prevent run-on and ninoff of
stormwater.
• Show secondary containment for
exterior work ateas where motor
oil, brake fluid, gasoline, diesel
fuel, radiator fluid, acid-containing
batteries or other hazardous
materials or hazardous wastes are
used or stored. Drains shall not be
installed within the secondary
containment areas.
• Add a note on the plans that states
either (1) there are no floor drains,
or (2) floor drains are connected to
wastewater pretreatment systems
prior to discharge to the sanitary
sewer and an industrial waste
discharge permit will be obtained.
State that no vehicle repair or
maintenance will be done outdoors, or
else describe the required features of
the outdoor work area.
State that there are no floor drains or if
there are floor drains, note the agency
from which an industrial waste
discharge pennit will be obtained and
that the design meets that agency's
requirements.
State that there are no tanks,
containers or sinks to be used for pans
cleaning or rinsing or, if there are, note
the agency from which an industrial
waste discharge permit will be
obtained and that the design meets
that agency's requirements.
•
•
In the SUSMP report, note that all of
the following restrictions apply to use
the site:
No person shaU dispose of, nor
permit the disposal, direcdy or
indirecdy of vehicle fluids, hazardous
materials, or rinsewater from parts
cleaning into storm drains.
No vehicle fluid removal shall be
performed outside a building, nor on
asphalt or ground surfaces, whether
inside or outside a building, except
in such a manner as to ensure that
any spilled fluid will be in an area of
secondary containment. Leaking
vehicle fluids shall be contained or
drained from the vehicle
immediately.
No person shall leave unattended
drip parts or other open containers
containing vehicle fluid, unless such
containers are in use or in an area of
secondary containment.
Page 6 of 9
• L. Fuel Dispensing
Areas a
•
Fueling areas' shall have
impermeable floors (i.e., pordand
cement concrete or equivalent
smooth impervious surface) that
are: a) graded at the minimum
slope necessary to prevent ponding;
and b) separated from the rest of
the site by a grade break that
prevents run-on of stormwater to
the maximum extent practicable.
Fueling areas shall be covered by a
canopy that extends a minimum of
ten feet in each direction from each
pump. [Alternative: The fueling
area must be covered and the
cover's minimum dimensions must
be equal to or greater than the area
within the grade break or fuel
dispensing area'.] The canopy [or
cover) shall not drain onto the
fueling area.
• The property owner shall dry sweep
the fueling area routinely.
• See the Business Guide Sheet,
"Automotive Service—Service
Starions" in the CASQA Stormwater
Quality Handbooks at
WTx-w.cabmphandbooks.cnm
Z!';Jh^hevc;T;t"c'::^ " '"^ ""'""^"^ ' "•'P'^"'" - - -^'^ --mbl^ .ay be operated plus a .i„i„,„„ „f
Page 7 of 9
• M. Loading Docks
N. Fire Sprinkler Test
Water
a
a
Show a preliminary design for the
loading dock area, including
roofing and drainage. Loading
docks shall be covered and/or
graded to minimize run-on to and
runoff from the loading area. Roof
downspouts shall be posidoned to
direct stormwater away from the
loading area. Water from loading
dock areas should be drained to thc
sanitary sewer where feasible.
Direct connecdons to storm drains
from depressed loading docks are
prohibited.
Loading dock areas draining
direcdy to the sanitary sewer shall
be equipped vrith a spill control
valve or equivalent device, which
shall be kept closed during periods
of operation.
Provide a roof overhang over the
loading area or install door skirts
(cowling) at each bay that enclose
the end ofthe trailer.
• Provide a means to drain fire sprinkler
test water to the sanitary sewer.
Move loaded and unloaded items
indoors as soon as possible.
See Fact Sheet SC-30, "Outdoor
Loading and Unloading," in thc
CASQA Stormwater Quality
Handbooks at
vy\^-w .cabmphandhonks r-nm
a See the note in Fact Sheet SC-41,
"Building and Grounds
Maintenance," in the CASQA
Stormwater Quality Handbooks at
www.cabmphandhooks.cnm
Page 8 of 9
O. Miscellaneous Drain
or Wash Water
• Boiler drain lines
• Condensate drain lines
• Rooftop equipment
• Drainage sumps
• Roofing, gutters, and
trim.
P. Plazas, sidewalks,
and parking lots.
•
Boiler drain lines shall be directly or
indirectly connected to the sanitary
sewer system and may not discharge
to the storm drain system.
Condensate drain lines may discharge
to landscaped areas ifthe flow is small
enough that runoff will not occur.
Condensate drain Unes may not
discharge to the storm drain system.
Rooftop mounted equipment with
potential to produce pollutants shall
be roofed and/or have secondary
containment.
Any drainage sumps on-site shall
feature a sediment sump to reduce the
quantity of sediment in pumped water.
Avoid roofing, gutters, and trim made
of copper or other unprotected metals
that may leach into nmoff.
CB'^Plazas, sidewalks, and parking lots
shall be swept regularly to prevent
the accumuladon of litter and debris.
Debris from pressure washing shall
be collected to prevent entry into the
storm drain system. Washwater
containing any cleaning agent or
degreaser shall be collected and
discharged to the sanitary sewer and
not discharged to a storm drain.
Page 9 of 9
SECTION 2: IDENTIFY POLLUTANTS, BMP SIZING AND SELECTION
.E5
Bnd of Decision
Matrix
Goto X
Figure 2.4 \
ofthe j
Oecisiofi /
\ Matrix '
1'KJL Ri-: 2-2, Mitirarion Ci-itcri:! and I mpl fine lUa tion 1
38 City of Carlsbad SUSMP - January 14, 2011
SECTION 2: IDENTIFY POLLUTANTS, BMP SIZING AND SELECTION
LABILE BED
•Sand-Dominated
•d , < 16 mm
•% Surface Sand > 2St
•Loosely-Packed
CHANNEL BED RESIST/WJCE
INTERMEDIATE BED
Woderatdyto Loosely-
Packed Cobble/Gravel
•Hardpan of Unccnain
Oepth. Bdent ErodibKly
COARSE/ARMORED BED
•d > 128 mm
•Boulder/Large Cobble
•Tiglttly-Packed
•at Ssni
•Coniifwwus Bedrock
•Continuous ConcMe
EXW^yllNE RISK FACTORS
•Grade Control
^Amofing Potential
•Proitimityio Incision Dueshidd
LOW
Ooto Bed ErDdibHIty
CheckNstf and Incision
Diagram Checklist
Fill out SCCWRP Scoring
Cnteria to Detennine ifthe
Receiwtg Channel has a HICH,
MEDIUM.orLOWSutoeiXibiKty
HIOH MEDIUM LOW
FIGURE 2-4. SCCWRP Vertical .Susreprihilit^. M.triv
44 City of Carisbad SUSMP - January 14, 2011
SECTION 2: IDENTIFY POLLUTANTS, BMP SIZING AN D SELECTION
c
• t
LOW
•FuBy Amored / B*<lrcnk Bank
Estabiasionin Good Condition
•No E«Uenceo( Chuie
Fonnation/Amlskms
«Fu«y Conined, Dimtt)'
Conheotedto HUde. VW-t
4—<TWEfiALLY ADJUSTABlir)
IT >E5
A'e LKenI
AJjujtnwnJs
Occuning?
1
IIO
Non«, or Fluvial Only linked to
fiends Mul Consbietion;
r
Mass Wistinj or
Bttensiue Fluviat
Bosianoi Ctwte
Cutoff FciTMtion
4 4 MEO HIGH
VWI«2 VWI>2
1 I
Modentelyor Wtll-Consolidated Al Bank Strata \ no
ConsoMaled
kwkidingTot?
Bank Height
<IDf Logistic
Risk fcr Aigle
Bank Heighl
>tO% Logistic
Risk for Aigle
MiOVm > 2
FIGURE 2-5. Lateral Channel Susceptihilin' Matrix
5£e ^TU>^
45 City of Carlsbad SUSIMP - January 14, 2011
EXIST. AC
= 0.20 AC
DOST. AC
PROPOSED PERVIOUS
= 013 AC
EXIST PERVIOUS
PROPOSED AC/CONC
= 0.13 AC
EXIST PERVIOUS
PROPOSED PERWXJS
= 001 AC
TOTAL AREA = 047 AC y '\ I i I ; j r' 14 n
/ / I I Hi I It \ t
NET IMPERVIOUS = 0\
EXHIBIT FOR
BIORETENTION RA<^N r
MARJA ACRES PR0PERTY\
UPDATED 5/6/2014
PREPARED 6/5/2013
G:\101307\Exhibits\ECR\BIOBASINF.dwg May 07, 2014 2:08pm
Xrefs: 1007WMAP; 1007ATP01: 1007AMAP: 1007WGRD: 1007WSTR: 1007WUTL: 1007AUTL7: 1007asite
Report Result Page 1 of2
Project Summary
Project Name El Camino Real Widening
Project Applicant Shapell Homes
Jurisdiction City of Cadsbad
Parcel (APN) 20801040
Hydrologic Unit Carlsbad
Compliance Basin Summary
Basin Name: Basin G- Super Elevated to Median at Marja Acres
Receding Water: Kelly Box Culvert
Rainfall Basin Oceanside
Mean Annual Precipitation (inches) 13.3
Project Basin Area (acres): 1,86
Watershed Area (acres): 11,50
SCCWRP Lateral Channel Susceptibiity (H, M, L): Low (Lateral)
SCCWRP Vertlflcal Channel Susceptibiity (H, M, L): Low (Vertical)
Overall Channel Susceptibility (H, M, L): LOW
Lower Flow Threshold (% of 2-Year Flow): 0.5
Drainage Management Area Summary
ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soil Slope
28010 Drains to LIO BMP 17 DMA Gl-1 0.19 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less ...
28011 Drains to LID BMP 17 DMAG1-2 0.03 Pervious (Pre) Landscaping Type D (high runoff - clay
soi... Steep (greater 10%)
28012 Drains to LID BMPn DMA G1-3 0.1 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi,.. Steep (greater 10%)
28013 Drains to LID BMPn DMAG1-4 0.06 Pervious (Pre) Landscaping Type D (high runoff - clay
soi,,. Flat - slope (less ...
28014 Drains to LID BMP/t DMA G2-1 0.16 Impervious (Pre) Concrete or asphalt Type D (high njnoff - day
sol.,. Flat - slope (less , .,
28015 Drains to LID BMP /6 DMAG2-2 0,02 Pervious (Pre) Landscaping Type D (high runoff - clay
soi... Steep (greater 10%)
http://iiknow.brwncald.com/wastewater/Toolldts/Watershed/SiteToolkit/ReportResult.aspx?pid= 138617«&bid=SDC-0001 &sic=n... 6/14/2013
Report Result Page 2 of2
28016 Drains to LID BMP ili DMA G2-3 0.1 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Steep (greater 10%)
28017 Drains to LID BMP Ilo DMA G2-4 0.06 Impervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less ..,
28018 Drains to LID BMP IS DMA G3-1 0.17 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less,,.
28019 Drains to LID BMP 1$ DMA G3-2 0,02 Pervious (Pre) Landscaping Type D (high ninoff - clay
soi.,. Steep (greater 10%)
28020 Drains to LID BMP 16 DMA G3-3 0.09 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Steep (greater 10%)
28021 Drains to LIO BMP /S DMAG3-4 0.09 Impervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less...
28023 Drains to LID mpil DMA G4-1 0.38 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
sol.,. Flat - slope (less ...
28024 Drains to LID BMP /V DMAG4-2 0.02 Pervious (Pre) Landscaping Type D (high runoff - clay
soi,,. Steep (greater 10%)
28026 Drains to LID BMP /V DMA G4-3 0.14 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Steep (greater 10%)
28027 Drains to LID BMP l^ DMAG4-4 0.23 Impervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less...
LID Facility Summary
BMP ID Type Description Plan Area (sqft) Volume 1(cft) Votume 2(cft) Orifice Flow (cfs) Oriflce Size (Inch)
BMP 17 Flow-Through Planter Bioretention 299 249 179 0.074 1,00
BMP li, Flow-Through Planter Bioretention 279 233 167 0.076 1.00
BMP 1$ Flow-Through Planter Bioretention 256 213 154 0,085 2.00
BMP /V Flow-Through Planter Bioretention 407 339 244 0,189 2.00
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Report Result Fage 1 of2
Project Summary
Project Name El Camlno Real Widening
Project Applicant Shapell Homes
Jurisdiction City of Carisbad
Parcel (APN) 20801040
Hydrologic Unit Cartsbad
Compliance Basin Summary
Basin Name: Basin H- S. of Kelly
Receiving Water: Box Culvert at Kelly
Rainfall Basin Oceanside
Mean Annual Precipitation (inches) 13.3
Project Basin Area (acres): 3,19
Watershed Area (acres): 11.52
SCCWRP Lateral Channel Susceptibiity (H, M, L): Low (Lateral)
SCCWRP Vertifical Channel Susceptibiity (H, M, L): Low (Vertical)
Overall Channel Susceptibility (H, M, L): LOW
Lower Flow Threshold (% of 2-Year Flow): 0,5
Drainage IVIanagement Area Summary
ID Type BMP ID Description Area (ac) Pre-ProJect Cover Post Surface Type Drainage Soil Slope
26963 Drains to LID BMPIg DMA Hl-1 0.48 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat-slope (less „,
26964 Drains to LID BMP lg DMAH1-2 0.58 Pervious (Pre) Landscaping Type D (high runoff - clay
soi... Steep (greater 10%)
26965 Drains to LID BMP 18 DMA H1-3 0.36 Pervbus (Pre) Concrete or asphalt Type D (high mnoff - clay
soi,.. Steep (greater 10%)
26966 Drains to LID BMP 18 DMA H1-4 0.2 Impervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less ...
26968 Drains to LID BMP /? DMA H2-1 0.42 Impervious (Pre) Concrete or asphalt Type D (high runoff - ciay
soi... Flat-slope (less.,,
26969 Drains to LID BMP/f DMA H2-2 0.46 Pervious (Pre) Landscaping Type D (high runoff - clay
soi,,. Steep (greater 10%)
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26970 Drains to LIO BMP I'j DMA H2-3 0.3 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Steep (greater 10%)
27026 Drains to LID BMP ^0 DMA H3-1 0.21 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
sol... Flat - slope (less...
27027 Drains to LID BMP 2JO DMA H3-2 0.08 Pervious (Pre) Landscaping Type D (high runoff - clay
soi... Flat - slope (less ...
27028 Drains to LID BMP to DMA H3-3 0.1 Pervious (Pre) Concrete or asphalt Type D (high mnoff - clay
soi... Moderate (5-10%)
LID Facility Summary
BMP ID Type [Jescription Plan Area (sqft) Volume 1(cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (inch)
BMP lg Flow-Through Planter Bioretention at Station 474+50 1063 886 637 0.304 3.00
BMP /<? Flow-Through Planter Bioretention at Toe S. of Box Culvert 860 717 516 0.209 2.00
BMP 2-(P Flow-Through Planter Bioretention adjacent Box Culvert 329 274 197 0.076 1.00
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Project Summary
Project Name El Camino Real Widening
Project Applicant Shapell Homes
Jurisdiction City of Carisbad
Parcel (APN) 20801040
Hydrologic Unit Carisbad
Compliance Basin Summary
Basin Name: Basin 1- N. of Kelly
Receiving Water: Biorelenlion Area N. of Box Culvert
Rainfall Basin Oceanside
Mean Annual Precipitation (Inches) 13.3
Project Basin Area (acres): 1.13
Watershed Area (acres): 11.52
SCCWRP Lateral Channel Susceptibiity (H, M, L): Low (Lateral)
SCCWRP Vertifical Channel Susceptibiity (H, M, L): Low (Vertical)
Overall Channel Susceptibility (H, M, L): LOW
Lower Flow Threshold (•^ of 2-Year Flow): 0.5
Drainage Management Area Summary
ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soil Slope
27031 Drains to LID BMP Zl DMA 1-1 0.51 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
sol... Flat - slope (less .„
27032 Drains to LID BMP-2,1 DMA 1-2 0.17 Pervious (Pre) Landscaping Type D (high runotT - clay
soi... Flat - slope (tess..,
27033 Drains lo LID BMP 21 DMA 1-3 0.37 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
sol... Flat - slope (less ...
27034 Drains to LID BMP Zl DMA 1-4 0.08 Impervious (Pre) Pervious concrete or asphalt Type D (high mnoff - clay
soi.,. Flat - slope (less...
LID Facility Summary
BMP ID Type Description Plan Area (sqft) Volume 1(cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (inch)
BMPZI Flow-Through Planter Bioretention N. of Box Culvert 1180 982 708 0.211 2.00
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Project Summary
Drainage Management Area Summary
Project Name El Camino Real Widening
Project Applicant Shapell Homes
Jurisdiction City of Carisbad
Parcel (APN) 20801040
Hydrologic Unit Cartsbad
Compliance Basin Summary
Basin Name: Basin J- S. of Tamaracic
Receiving Water: Kelly Drive Box Culvert
Rainfall Basin Oceanside
Mean Annual Precipitation (Inches) 13.3
Project Basin Area (acres): 0.86
Watershed Area (acres): 11.50
SCCWRP Lateral Channel Susceptibiity (H, M, L): Low (Lateral)
SCCWRP Vertifical Channel Susceptibiity (H, M, L): Low (Vertical)
Overall Channel Susceptibility (H, M, L): LOW
Lower Flow Threshold (% of 2-Year Flow): 0.5
ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soil Slope
27113 Drains to LID BMP Z3 DMAJ1-2 0.44 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi,.. Fiat - slope (less ,.,
27114 Drains to LID BMP23 DMA J1-2 0.06 Pervious (Pre) Landscaping Type D (high runoff - clay
soi... Flat-slope (less..,
27115 Drains to LID BMPZ3 DMAJ1-3 0.15 Pen/ious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less „.
27116 Drains to LID BMP 23 DMAJ1-4 0.05 Impervious (Pre) Pervious concrete or asphalt Type 0 (high runoff - clay
soi... Flat - slope (less „.
27117 Drains to LID BMP2Z DMAJ2-1 0.05 Impervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less.,.
27118 Drains to LID BMP 21 DMAJ2-2 0.02 Pervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi.,. Flat - slope (less...
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27119 Drains to LID BMP 22. DMA J2-3 0.06 Pervious (Pre) Concrete or asphalt Type D (high runoff - clay
soi... Flat - siope (iess ...
27120 Drains to LID BMP 22 DMAJ2-4 0.03 Impervious (Pre) Pervious concrete or asphalt Type D (high runoff - clay
soi... Flat - slope (less ,..
LID Facility Summary
BMP ID Type Description Plan Area (sqft) Volume 1(cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (Inch)
BMP Z3 Flow-Through Planter Bioretention Area 1 475 396 285 0.155 2.00
BMP2Z Flow-Through Planter Bioretention Area 2 189 157 113 0.029 0,9
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ATTACHMENT 12
SOIL RECOMMENDATIONS FOR BIORETENTION AND PERVIOUS
PAVEMENT
NATIVE SOIL
We assumed the soil at the site is Type 'D' as shown on the BMP Calculator Output in
Attachment 11. In the Supplemental to the Updated Geotechnical Investigation for
Rancho Costera (Formerly Robertson Ranch West Village) for Shappell Homes,
prepared by GeoSoils, Inc. on June 6, 2011, (Reference 1) the calculated inflitration rates
of 0.18 in/hr for the artificial fill areas and between 0.16 and 0.06 in/hour for the bedrock
materials were found at the site. According to the County of San Diego Guidelines for
Determining Significance, Surface Water Quality, dated July 30, 2007, (Reference 2) soil
infiltration rates for Type 'D' soil are 0 to 0.05 inches per hour. Conclusively, the soil on
site has slightly higher infiltration rates then the minimum infiltration rates delineated by
the County of San Diego for Type 'D'. However, in order to maintain a more
conservative IMP design we will use Type 'D' for our IMP calculations. Excerpts from
reference 1 and 2 above are attached below.
exhibit an adequate FOS (i.e., >1.5) against surficial failure, provided ttiat the slopes are
properiy constructed and maintained, under normal rainfall.
Terrace deposits and Santiago Formation bedrock contain granular, sandy soil. If sandy
soils with a cohesion of less than 200 psf are used on slope faces derived from these
deposits, the slopes may have surficial stability/erosion issues and perhaps a FOS against
surficial instability of less than 1.5. Planting and management of surficial drainage is
imperative to the surficial performance of slopes. Typically, similar to coastal bluff retreat,
a surficial erosion rate (average) of about VA inches/year for natural and unprotected
sandy slopes may be assumed. Foot traffic and other activities that exacerbate surficial
erosion should not be allowed to occur on slopes. Failure to adhere to these conditions
may drastically increase and localize surficial erosion, requiring mitigation, so that
headward erosion does not result, and impact roadways, pads, and other improvements.
pigpnpH Fili Over Cut Slopes
Fill over cut slopes shown on Plates 1 and 3 are generally considered to be grossly stable.
However, the cut/fill transition that daylights at the slope face represents a permeability
contrast that will accumulate water (i.e., perched groundwater), resulting in seepage atthe
slope face. Such seepage will saturate near surface soils, resulting in loss of soil strength
and an increased potential for surficial slope failure(s). In orderto mitigate this condition,
as well asthe potential for perched groundwater up-gradient, fill over cut slopes should be
reconstructed as a stabilization fill slopes. In the case ofthe larger fill (up to approximately
45 feet) over cut slope above El Camino Real (see Plate 2, Cross Section F-F') the fill key
may be provided with a subdrain/backdrain as recommended in Appendix F. As stated
previously, the backcut was considered stable for Cross Section F-F' due the anticipated
2:1 inclination (Plate 2). Furthermore, the face cuts and backcuts up to 1.5:1 (h:v) are
considered stable (FOS >1.2)
INFILTRATiON TESTING
General
It is our understanding that the controlling authorities are requiring onsite
Best Management Practices (BMP's) to clarify and filter onsite storm water run-off within
the project. Currently, it is unknown what type of BMP will be utilized for the project
(i.e., bio-swales, detention/infiltration basins, sand filters, etc.), however;
detention/infiltration basin BMP's are generally utilized for residential developments to
clarify and filter onsite storm water during rain events.
Three (3) infiltration tests were conducted to evaluate site soils with respect to anticipated
BMP's onsite. One (1) infiltration test was conducted within previously compacted fill
f^aterials onsite (depth of approximately ±3 feet) and two (2) infiltration tests were
ShapdTHom^^ ~ ' W.O. 6145-Al-SC
Rancho Costera, Carlsbad June 6, 2011
•"^'e e.Hvpffei00,6145a1 stt PaQS 9
GeoSoils, Inc.
Accuracy:
Test Results:
onsite earth materials in relation the anticipated
detention/infiltration systems and/or other BMP's selec e^^^
design engineer. The approximate locations of the infiltration
tests conducted are provided on the enclosed Plate 1.
All measurements within the inner and outer ring were read to
the nearest 1/16 inch. All test measurements wi hin he
graduated mariotte tubes were read to the nearest millimeter.
The calculated rates from the double-ring infiltration testing
performed during this study are 0.18,0.16. and 0.06 mch/hour
for Infiltration Test IT-1, IT-2. and IT-3, respectively The
relatively low infiltration rates obtained are likely due to clay
content of the artificial fill (IT-1) and the relative density and
indurated nature of the bedrock matenals (IT-2 and IT-3)
onsite. As indicated previously, the field test data is provided
in Appendix E.
goQciusions^ildR^
^ ^ th. rairulated infiltration rate of 0.18 inch/hour for the artificial fill and
AS iridicated above, the cak:^ ^^^^.^^^ ^ depth of
between 0.16 and 0.06 '"'^h/hour Tor ine • 1^
approximately ±3 feet, may be utilized for desigr^ Ja^eW per the controlling authorities
r:rn.rshr;ai:o=r^^^^^^^^^^^
BMP systems onsite:
. As with any BMP detention/infiltration device, localized ponding and groundwater
seepage should be anticipated.
• Similarlv as with any BMP detention/infiltration device, proper maintenance and
c^Te wl^'need ?o provided. Best management -aintenance prac.ces shou^^^^^^^^
followed at all times, especially during inclement weather. Should mgu a
inspection and/or required maintenance not be performed, the potential for
malftjnctioning of the detention/infiltration systems will increase.
* Provisions for the maintenance of any siltation. debris, and/or Q^^^^^Qf
(i e root svstems) should be considered. An appropriate inspect on and
maintrance'schedule will need to adopted and provided to all interested/affected
parties.
^«PeH Homes
^cho Costera, Carlsbad
W.O. 6145-A1-SC
June 6, 2011
Page 11
n.i»n.CMt€. Inc.
1.6 Infiltration and Runoff i-^f J>:fdfK. 0^. '
Infiltration of water through soil can reduce the amount of water that reaches stormwater
management systems, filter pollutants and contaminants from the water, and recharge
the watershed. The USDA Natural Resources Conservation Service (NRCS- formerly
the Soil Conservation Service [SCS]), classifies a soil's infiltration characteristics into
four Hydrologic Soil Groups (HSG):
Group A: Low runoff potential. Soils having high infiltration rates even when
thoroughly wetted and consisfing chiefly of deep, well-drained sands or gravels.
Group B: Soils having moderate infiltration rates when thoroughly wetted and
consisting chiefly of moderately deep to deep, moderately well- to well-drained
sandy loam soils with moderately fine to moderately coarse textures.
Group C: Soils having slow infiltration rates when thoroughly wetted and
consisting chiefly of silty-loam soils with a layer that impedes downward
movement of water, or soils with moderately fine to fine texture.
Group D: High runoff potenfial. Soils having very slow infiltrafion rates when
thoroughly wetted and consisfing chiefly of clay soils with a high swelling
potenfial, soils with a permanent high water table, soils with a claypan or clay
layer at or near the surface, and shallow soils over nearly impervious material.
Group A and B soils possess the greatest infiltration rates (unless soils are compacted
during construction) and are generally best suited to stormwater infiltration. However
the San Diego Area has a relatively high concentrafion of Group C and D soils which
possess lower infiltration rates that either limit the use of infiltration-based stormwater
management systems or require soil amendments to assist infiltrafion systems.
For a specific site, the HSG designation can be obtained by referring to a local soil
survey, by consulting the complete nafional lisfing given in NRCS, or by performing an
on-site invesfigation. Soil Survey maps can be obtained from local NRCS offices or on-
line for use In estimafing soil type. The NRCS maps are also available at the County of
San Diego, Department of Public Works. Consideration should be given to the effects of
urbanizafion on the natural hydrologic soil group. If heavy equipment can be expected
to compact the soil during construcfion or if grading will mix the surface and subsurface
soils, appropriate changes should be made in the soil group selected (SD Countv
Hydrology Manual 2003).
The table below presents soil infiltration rates for each soil group determined by
laboratory studies and measurements. Site designers should compare the design
runoff volume with the available soil storage volume to determine if infiltration is
feasible, and then use the infiltrafion rates to determine if the design runoff volume can
infiltrate within a reasonable time (generally 24 to 48 hours). For sites with Group C and
http://websoilsurvev,nrcs,uscia.qov/aDD/
Guidelines for Determining Significance ~ ~~~ ~ ~—^
Surface Water Quality
D soils, retention- and detention based strategies are often more feasible than
infiltrafion designs.
TABLE 1
TYPICAL SOIL INFILTRATION RATES.
Minimum Infiltration Rate
Soil Type (inches per hour)
A 0.30 to 0.45
B 0.15 to 0.30
C 0.05 to 0.15
D 0 to 0.05
In general, absorption of surface runoff by clay soils is low and reached quickly,
whereas in sandy soils a larger portion of the runoff infiltrates the land surface and
recharges the underiying groundwater system, resulting in less runoff.
1.7 Beneficial Uses of Water
Beneficial uses are defined as. "uses of water necessary for the survival or well being of
people, plants and wildlife." In San Diego County, residents, visitors and nature rely on
the region's water resources to provide beneficial uses such as ensuring a clean and
available drinking water supply, supporting agricultural, commercial, industrial,
recreational, residenfial, and military uses, and supporting wildlife and habitat. The
State Water Resources Control Board (SWRCB) has adopted a uniform list and
description of beneficial uses to be applied throughout all basins of the State
(Attachment B). These uses of water serve to promote the tangible and intangible
economic, social and environmental goals identified in the Water Quality Control Plan
for the San Diego Basin (9) prepared by the RWQCB
(www.swrcb.ca.qov/rwqcb9/proqrams/basinplan.html).
1.8 Stormwater Drainage Svstems
Within urban areas stormwater and sewage systems run parallel but are not combined.
A vast amount of the unincorporated San Diego County is rural land that does not
support or require stormwater drainage facilities. In contrast, most urban areas within
unincorporated San Diego County have a range of stormwater drainage facilities, all of
which will continue to be improved as new discrefionary projects are constructed.
Collectively, stormwater drainage facilities make up a stormwater conveyance system.
A stormwater conveyance system as defined by the County of San Diego Watershed
Protection, Stormwater Management, and Discharge Control Ordinance, "means private
and public drainage facilities other than sanitary sewers within the unincorporated areas
of San Diego County by which urban run-off may be conveyed to receiving waters, and
includes but is not limited to roads, streets, constructed channels, aqueducts, storm
drain, pipes, street gutters, inlets to storm drains or pipes, and catch basins."
Guidelines for Determining Significance
Surface Water Quality
HYDROMODIFICATION SCREENING
FOR
RANCHO COSTERA
(ROBERTSON RANCH PLANNING AREAS 1-11,13, & 23A-C)
AND
EL CAMINO REAL WIDENING
June 19, 2013
Wayne W, Chang.
ClianBSDaMJMDiS
Civil Engineering ° Hydrology ° Hydraulics»Sedimentation
P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692-0760
I
I
i
I
I
-TABLE OF CONTENTS -
Introduction 1
Domain of Analysis 3
Initial Desktop Analysis 6
Field Screening 7
Conclusion 12
Figures 13
APPENDICES
A. SCCWRP Initial Desktop Analysis
B. SCCWRP Field Screening Data
MAP POCKET
Study Area Exhibit
Rancho Costera Drainage Study - Proposed Condition Work Map
I
Plan) and the adjacent El Camino Real widening project. Both projects are being designed by
O'Day Consultants, Inc. (O'Day). Rancho Costera is located south of Calavera Hills Unit 1 (CT
76-12), west of Tamarack Avenue, and north of El Camino Real (see the Vicinity Map and the
Study Area Exhibit in the map pocket). The El Camino Real widening is along the soudi side of
Rancho Costera and will extend from Tamarack Avenue on the west to Cannon Road on the east.
The Rancho Costera site is currently undeveloped and supports agricultural uses. The proposed
site development varies by plarming area (PA): PA 1 and 23A-C are designated as open space;
PA 2 is a community facility site; PA 3, 5, 6, 9 and 10 are single-family residential
developments; PA 4 is for community recreation, PA 7 and 8 are multi-family residential; and
PA 11 is designated village center/commercial. Both projects are subject to hydromodification
requirements because they are priority development projects. A variety of best management
practices (bioretention basins, bioswales, etc.) wdll be incorporated throughout the projects to
treat runoff from the development areas.
Under pre-project conditions, storm runoff from the Rancho Costera site generally flows towards
the south and occurs as sheet flow over die natural ground or as surface flow within natural
drainage courses. Tlie majority of tiiis runoff is conveyed to an existing double 8-foot by 4-foot
reinforced concrete box culvert (RCB) under El Camino Real east of Kelly Drive or to an
existing 8-foot by 8-foot RCB under El Camino Real west of Cannon Road. Some of the runoff
will also flow onto El Caraino Real where it will be collected by public storm drain systems
along with the roadway runoff The runoff from all of these areas is ultimately conveyed to Agua
Hedionda Creek, which outlets into the Agua Hedionda Lagoon and then the Pacific Ocean.
Under post-project conditions, proposed storm drain systems will be constructed to serve Rancho
Costera and the existing El Camino Real storm drain system will be altered to accommodate the
widening. However, the storm runoff will continue to be conveyed to Agua Hedionda
Creek/Lagoon and the Pacific Ocean.
The SCCWRP screening tool requires both office and field work to establish the vertical and
lateral susceptibility of a natural downstream receiving channel to erosion. In this case, there are
multiple natural downstream receiving channels near the easterly portion of the site and one
natural receiving channel along the westerly portion of the site (see the Study Area Exhibit in the
map pocket). The easterly natural charmels confluence then flow to Agua Hedionda Creek, while
the westerly natural chaimel flows into the Kelly Drive concrete-lined trapezoidal chaimel, which
discharges to Agua Hedionda Creek. The vertical and lateral assessments are performed
independently of each other although the lateral results can be affected by the vertical rating. A
screening analysis was performed to assess the low flow threshold for the project's points of
compliance, which are at each of the storm drain outlets into the natural channels.
The initial step in performing the SCCWRP screening analysis is to establish the domain of
analysis and the study reaches within the domain. This is followed by office and field
components of the screening tool along with the associated analyses and results. The following
sections cover these procedures in sequence.
I
I
DOMAIN OF ANALYSIS
SCCWRP defines an upstream and downstream domain of analysis, which establish the study
limits. The County of San Diego's HMP specifies the downstream domain of analysis based on
the SCCWRP criteria. The HMP indicates tliat the dovrastream domain is the flrst point where
one of these is reached:
• at least one reach downstream of the first grade control point
• tidal backwater/lentic waterbody
• equal order tributary
• accumulation of 50 percent drainage area for stream systems or 100 percent drainage area
for urban conveyance systems (storm drains, hardened channels, etc.)
The upstream limit is defined as:
• proceed upstream for 20 channel top widths or to the first grade control point, whichever
comes first. Identify hard points that can check headward migration and evidence of
active headcutting.
SCCWRP defines the maximum spatial unit, or reach (a reach is circa 20 channel widths), for
assigning a susceptibility rating within the domaui of analysis to be 200 meters (656 feet). If tiie
domain of analysis is greater than 200 meters, the study area should be subdivided into smaller
reaches of less than 200 meters for analysis. Most of the units in the HMP's SCCWRP analysis
are metric. Metric units are used in this report only where given so in the HMP. Otherwise
English units are used.
Downstream Domain of Analvsis
The downstream domain of analysis for a study area is determined by assessing and comparing
the four bullet items above. As discussed in tiie Introduction, the project has a point of
compliance (POC) at each of the storm drain outlets into a natural channel. In this case, there are
natural channels along the easterly and westerly portions of the site. Tiierefore, a downstream
domain of analysis location will be selected below the downstream-most POC in both the
easterly and the westerly channels.
The Study Area Exhibit shows several proposed storm drain outfalls into natural channels along
the easterly portion of the site. These channels ultimately confluence upstream of El Camino
Real and flow to Agua Hedionda Creek south of El Camino Real. Some of tiie outfalls discharge
at essentially the same location along a natural channel, so these fomi a single POC. The total
number of POCs into the easterly charmels is twelve (labeled A through L on the Study Area
Exhibit). The downstream-most POC within the easterly channels is POC L.
The Study Area Exhibit shows four POCs (labeled M through P) within the natural channel
along the westerly portion of the site. The downstream-most POC along this channel is POC P.
Therefore, dovrastream domain of analysis locations will be determined below POC L to the east
and POC P to the west, and were assessed as follows.
Per the first bullet item, the first permanent grade control point was located below POC L and
POC P through a site investigation and review of aerial photographs. The waterbodies below
POC L are Agua Hedionda Creek, Agua Hedionda Lagoon, and the Pacific Ocean. There are no
permanent grade controls within these waterbodies below POL L, so tiiis first criteria does not
apply for POCL.
For POC P, tiie natural receiving watercourse continues for over 1,000 feet, where it becomes the
concrete-lined Kelly Drive trapezoidal channel. The Kelly Drive channel was recently repaired
by the City of Carlsbad. Chang Consultants was under contract witii Clayton Dobbs and Sherri
Howard at the City and assisted in obtaining the resource agency permits for the repairs. Since
the channel is concrete and a primary public drainage facility, it is considered a permanent grade
control. Therefore, the upper end of tiie Kelly Drive channel is the first permanent grade control
below POC P.
The second bullet item is the tidal backwater or lentic (standing or still water such as ponds,
pools, marshes, lakes, etc.) waterbody location. The nearest significant tidal backwater or lentic
waterbody is for POC L and P is Agua Hedionda Lagoon. From Google Earth, the upstream
extent of the lagoon is over 4,500 feet dovrastream of POC P. For POC L, the lagoon is
downstream ofthe Kelly Drive channel permanent grade control, so the lagoon will not govem
for establishing tiie downstream domain of analysis location.
The final two bullet items are based on 50 and 100 percent tributary drainage areas (in this case,
the charmels are in urban areas, so the 100 percent criteria will be used). The natural channel
below POC L confluences with Agua Hedionda Creek approximately 220 feet below POC L.
The overall area tributary to POC L covers approximately 5.11 square miles according to a 2008
Letter of Map Revision Request for Robertson's Ranch by Chang Consultants. In comparison,
FEMA's May 16, 2012, Flood Insurance Study indicates tiiat tiie Agua Hedionda Creek
watershed covers 23.8 square miles at El Camino Real (see Appendix A for excerpts from botii
reports). Tliis infomiation shows that the Aqua Hedionda Creek tributary drainage area is much
greater than 100 percent of the POC L drainage area. In addition, for POC P, a 100 percent larger
drainage area occurs where the Kelly Drive channel confluences with Agua Hedionda Creek.
Therefore, for both POCs the tributary area criteria is met where their downstream channels
confluence vnth Agua Hedionda Creek.
Based on the above information, the dovrastream domain of analysis below POC L occurs at the
confluence with Agua Hedionda Creek, which is approximately 220 feet downstream of POC L.
There is no permanent grade control associated with POC L and the tidal backwater is several
thousand feet fiirtiier downstream of the confluence.
The dovrastream domain of analysis for the natural channel tributary to POC P is at the
permanent grade control created at the upper end ofthe Kelly Drive concrete-lined channel. The
tidal backwater and 100 percent tributary area are fiirther downstream of tiie Kelly Drive
channel. Per die first bullet item, the downstream domain of analysis is one reach below the
grade control point. As outlined above, a reach is not to exceed 200 meters (656 feet). The
concrete-lined channel is longer tiian 656 feet, so the reach will be within the non-erodible
channel. Therefore, the dovrastream domain of analysis for the study reach associated with POC
P occurs at the upper end of the Kelly Drive channel.
Upstream Domain of Analvsis
The upstream domain of analysis must be established for the easteriy and westerly natural
channels. Along the easterly side, there are three upstream-most POCs: POC A, POC B, and
POC H (see the Study Area Exhibit). The outlet of each of these is essentially at the upstream
end of the receiving natural channel. Since the area upstream of tiiese three POCs is not an
erodible channel, each POC establishes an upstream domain of analysis location.
Along tiie westeriy side, the upstream-most POC is POC M, and tiie watercourse above POC M
begins at the southerly edge of Tamarack Avenue approximately 290 feet above POC M.
Therefore, the upstream domain of analysis location for the westerly natural channel is at the
southerly edge of Tamarack Avenue.
Studv Reaches within Domain of Analvsis
The total domain of analysis (or overall study reach) within the easterly area extends from the
three upstream POCs to Agua Hedionda Creek south of El Camino Real. The total domain of
analysis for the various natural channels within the westerly area covers approximately 6,241
feet (1,902 meters). The domain of analysis was subdivided into eight natural study reaches witii
similar characteristics (see the Study Area Exhibit). Reach El extends 2,700 feet (823 meters)
from the upstream domain of analysis location at POC A dovra to POC F, which is at a channel
confluence. Reach E2 extends 1,253 feet (382 meters) from the upstream domain of analysis
location at POC B to POC C. Reach E3 extends 244 feet (74 meters) from POC C to POC D.
POC D and E are at the upstream and downstream ends ofthe proposed Street E culvert crossing
ofthe channel. Reach E4 extends 687 feet (209 meters) from POC E to the channel confluence at
POC F. Reach E5 extends 250 feet (76 meters) from POC F to an existing concrete-lined access
road crossing the natural channel. Reach E6 extends 284 feet (87 meters) from the access road to
POC G, which is located at tiie upstream end of the existing 8-foot by 8-foot RCBs under El
Camino Real. Reach E7 extends 603 feet (184 meters) from the upstream domain of analysis
location at POC H to POC G. Reach E8 extends 220 feet (67 meters) from POC L at the
dovrastream end oftiie 8-foot by 8-foot RCBs under El Camino Real to the downstream domain
of analysis location at the confluence with Agua Hedionda Creek.
The total domain of analysis for the westerly area covers approximately 2,546 feet (776 meters).
Reach Wl begins at tiie upstream domain of analysis location on the south side of Tamarack
Avenue and extends 290 feet (88 meters) to the upstream end of the proposed Street J access
road from Tamarack Avenue. Street J crosses the stream channel and will contain a culvert to
convey the stream flow through the roadway embankment. Reach W2 extends 309 feet (94
meters) from POC M at the lower end of the proposed Street J culvert to POC N. Reach W3
extends 940 feet (287 meters) from POC N to POC O, which is located at the upstream end of
the existing double 8-foot by 4-foot RCBs under El Camino Real. POC P is at the downstream
end of the existing double 8-foot by 4-foot RCBs under El Camino Real. Reach W4 extends
1,007 feet (307 meters) from POC P to tiie downstream domain of analysis location at the upper
end of the concrete-lined Kelly Drive channel.
Several of the study reaches are longer than the 656 feet (200 meters) maximum reach length
specified by SCCWRP. Review of topographic mapping, aerial photographs, and field conditions
reveals that the physical (channel geometry and longitudinal slope), vegetative, hydraulic, and
soil conditions within each of the reaches are relatively uniform. Subdividing tiie reaches into
smaller subreaches of less than 656 feet will not yield significantly varying results within a
reach. Although the screening tool was applied across the entire length of each study reach, the
results will be similar for shorter subreaches within each reach.
INITIAL DESKTOP ANALYSIS
After the domain of analysis is established, SCCWRP requires an "initial desktop analysis" that
involves office work. The initial desktop analysis establishes the watershed area, mean annual
precipitation, valley slope, and valley width. These terms are defmed in Form 1, which is
included in Appendix A. SCCWRP reconimends the use of National Elevation Data (NED) to
detemiine the watershed area, valley slope, and valley width. The NED data is similar to USGS
mapping. For this report, O'Day's proposed condition hydrology tiata was used, where available,
to identify the drainage areas, which is more accurate than using NED data. The relevant pages
frora O'Day's hydrology analyses are included in Appendix A and their workmap is included in
the map pocket. O'Day's analyses do not provide drainage areas for Reach E7, E8, or W4, so
these were obtained as follows. Chang Consultants prepared a 2008 Letter of Map Revision
Request for Robertson's Ranch that delineated the tributary drainage areas to Reach E7 and E8,
so the LOMR data was used (see Appendix A for excerpts). For Reach W4, O'Day's analyses
determined the tributary area at the upper end of tiie reach. The additional area tributary to the
lower end of Reach W4 was delineated from tiie project's topographic mapping to determine the
total drainage area tributary to Reach W4. The delineation is included on the Study Area Exhibit.
The mean annual precipitation is provided by tiie County of San Diego's BMP Sizing Calculator
(see Appendix A) and is 13.3 inches.
The valley slopes of each smdy reach were determined from the 2-foot contour interval mapping
prepared for the project, where available, and the City's 2-foot contour interval topographic
mapping for a small area at the east. The valley slope is the longitudinal slope of tiie channel bed
along the flow line, so it is determined by dividing the elevation difference within a reach by the
flow path. The 2-foot contour mapping sources were used because they will provide more
precise results tiian NED data.
The valley width is the bottom widtii ofthe raain creek channel. The average valley width within
each reach was estimated from the 2-foot contour interval topographic mapping, field
observations, and review of aerial photographs. The valley slope and valley width for each reach
are summarized in Table 1.
These values were input to a spreadsheet to calculate the simulated peak flow, screening index,
and valley width index outiined in Form 1. The input data and results are tabulated in Appendix
A. This completes the initial desktop analysis.
I
Reach Tributary Area, sq. mL VaUey Slope, m/m Valley Width, m
El 0.2400 0.0289 6.1
E2 0.0731 0.0551 1.5
E3 0.0732 0.0369 1.5
E4 0.1272 0.0247 8.5
E5 0.3963 0.0092 11.0
E6 0.3964 0.0088 4.6
E7 4.6800 0.0060 16.8
E8 5.1100 0.0091 25.9
Wl 0.0054 0.0448 2.4
W2 0.8078 0.0191 6.1
W3 1.1157 0.0127 17.7
W4 1.2688 0.0183 4.9
Tabie 1. Summary of Valley Slope and Valley Width
FIELD SCREENING
After the initial desktop analysis is complete, a field assessment must be performed. The field
assessment is used to establish a natural channel's vertical and lateral susceptibility to erosion.
SCCWRP states that although they are admittedly linked, vertical and lateral susceptibility are
assessed separately for several reasons. First, vertical and lateral responses are primarily
controlled by different types of resistance, which, when assessed separately, may improve ease
of use and lead to increased repeatability compared to an integrated, cross-dimensional
assessment. Second, the mechanistic differences between vertical and lateral responses point to
different modeling tools and potentially different management strategies. Having separate
screening ratings may better direct users and managers to the most appropriate tools for
subsequent analyses.
The field screening tool uses combinations of decision trees and checklists. Decision trees are
typically used when a question can be answered fairly definitively and/or quantitatively (e.g., dso
< 16 mm). Checklists are used where answers are relatively qualitative (e.g., the condition of a
grade control). Low, medium, high, and very high ratings are applied separately to the vertical
and lateral analyses. When the vertical and lateral analyses return divergent values, the most
conservative value shall be selected as the flow threshold for the hydromodification analyses.
Visual observation reveals that most of the study reaches contain a moderate to densely
vegetated channel (see the figures following the report text). The vegetative density extends
relatively uniformly across the channel bottom and sides. Due to the vegetative cover, riprap
energy dissipaters at each POC, and lack of significant erosion noted during the site
investigation, the vertical and lateral stability was anticipated to have a limited susceptibility to
erosion.
Veriical Stabilin>
The purpose ofthe vertical stability decision tree (Figure 6-4 in the County of San Diego HMP)
is to assess the state of the channel bed with a particular focus on the risk of incision (i.e., down
cutting). The decision tree is included in Figure 30. The first step is to assess tiie channel bed
resistance. There are three categories defined as follows:
1. Labile Bed - sand-dominated bed, little resistant substrate.
2. Transitional/Intermediate Bed - bed typically characterized by gravel/small cobble.
Intermediate level of resistance of the substrate and uncertain potential for armoring.
3. Threshold Bed (Coarse/Armored Bed) - armored witii large cobbles or larger bed
material or highly-resistant bed substrate (i.e., bedrock).
Channel bed resistance is a fijnction of the bed material and vegetation. The figures after this
report text contain photographs of the natural channels in each study reach. A site investigation
and the figures indicate that the vegetative cover throughout each natural channel within Reaches
El through E4, E8, and Wl through W4 is mature, dense, and fairly uniform (see Figures 1
through 10 and 17 through 26). The vegetation in some areas is so dense diat tiie channel was
either difficult to access or not possible to access at all unless the vegetation is trimmed. The
vegetation consists of a variety of mature grasses, reeds, shrubs, and trees. Vegetation prevents
bed incision because its root stracture binds soil and because the aboveground vegetative growtii
reduces flow velocities. Table 5-13 from the County of San Diego's Drainage Design Manual
outiines maximum permissible velocities for various channel linings (see Table 5-13 in
Appendix B). Maxiraum pennissible velocity is defined in the raanual as the velocity below
which a channel section will remain stable, i.e., not erode. Table 5-13 indicates tiiat a fiilly-lined
channel witii unreinforced vegetation has a maxiraum permissible velocity of 5 feet per second
(fps). Due to the dense cover and mature vegetation, the permissible velocity when erosion can
initiate is likely greater than 5 fps in most of the natural channel areas. Table 5-13 indicates that
5 fps is equivalent to an unvegetated channel containing cobbles (grain size from 64 to 256 mm)
and shingles (rounded cobbles). In coraparison, coarse gravel (19 to 75 mm) has a maximum
pennissible velocity of 4 fps. Based on this information, the uniformly vegetated natural canyons
in Reaches El through E4, E8, and Wl through W4 has an equivalent grain size of at least 64
mm, which is comparable to a transitional/intermediate bed.
Figures 11 through 16 show that Reaches E5 through E7 contain sparser vegetation than the
otiier reaches. Therefore, a relationship between vegetative cover and grain size is not apphcable,
and pebble count must be performed. Figures 15 through 17 contain photographs of the typical
bed material within these three study reaches. A gravelometer is included in the photographs for
reference. Each square on tiie gravelometer indicates grain size in millimeters (the squares range
from 2 mm to 180 mm). A pebble count was performed (see results in Appendix A) that
determined the median (dso) bed material size to be 11 millimeters (mm) in Reaches E5, E6, and
E7.
In addition to the material size, there are several factors that establish the erodibility of a channel
such as the flow rate (i.e., size of the tributary area), grade controls, channel slope, vegetative
cover, channel planfonn, etc. The Introduction of the SCCWRP Hydromodification Screening
Tools: Field Manual identifies several of these factors. When multiple factors influence
erodibility, it is appropriate to perform the more detailed SCCWRP analysis, which is to analyze
a channel according to SCCWRP's transitional/intermediate bed procedure. This requires the
most rigorous steps and will generate the appropriate results given the range of factors tiiat
define erodibility. The transitional/ intermediate bed procedure takes into account that bed
material may fall within the labile category (the bed material size is used in SCCWRP's Form 3
Figure 4), but other factors may trend towards a less erodible condition. Dr. Eric Stein from
SCCWRP, who co-authored the Hydromodification Screening Tools: Field Manual in the Final
Hydromodification Management Plan (HMP), indicated that it would be appropriate to analyze
channels with multiple factors that impact erodibility using the transitional/intermediate bed
procedure. Consequently, this procedure was used to produce more accurate results for each
study reach.
Transitional/intermediate beds cover a wide susceptibility/potential response range and need to
be assessed in greater detail to develop a weight of evidence for the appropriate screening rating.
The three primary risk factors used to assess vertical susceptibiUty for channels witii
transitional/intermediate bed materials are:
1. Armoring potential - three states (Checklist 1)
2. Grade control - three states (Checklist 2)
3. Proximity to regionally-calibrated incision^raiding threshold (Mobility Index Threshold
- Probability Diagram)
These three risk factors are assessed using checklists and a diagram (see Appendix B), and the
results of each are combined to provide a final vertical susceptibility rating for the
intermediate/transitional bed-material group. Each checklist and diagram contains a Category A,
B, or C rating. Category A is the most resistant to vertical changes while Category C is the raost
susceptible.
Checklist 1 determines armoring potential of the chamiel bed. The channel bed along each ofthe
twelve reaches is within category B, which represents intermediate bed material within unknown
armoring potential due to a surface veneer and dense vegetation. The soil was probed and
penetration was relatively difficult through the underlying layer of each reach. Due to the dense
vegetative growth in some reaches, the armoring potential could have been rated higher in those
reaches, but Category B was conservatively (i.e., more potential for channel incision) chosen.
Checklist 2 determines grade control characteristics of the channel bed. SCCWRP states that
grade controls can be natural. Examples are vegetation or confluences with a larger waterbody.
As indicated above and verified witii photographs, Reaches El through E4, E8, and Wl through
W4 contain dense vegetation (see tiie figures). The plant roots and tree trunks serve as a natural
grade control. The spacing of these is much closer than die 50 meters or 2/Sv values identified in
the checklist. Further evidence of the effectiveness of the natural grade controls is the absence of
headcutting and mass wasting (large vertical erosion of a channel bank). Based on this
information, Reaches El through E4, E8, and Wl through W4 are within Category A on
Checklist 2.
Reaches E5 tiirough E7 do not contain dense vegetation. However, each of these reaches has a
grade control at their downstream end. For Reach E5, the existing concrete-lined access road
crossing ofthe natural channel (see Figure 13) is a permanent grade control. For Reaches E6 and
E7, the existing 8-foot by 8-foot RCB under El Camino Real is a pemianent grade control (see
Study Area Exhibit). Table 2 summarizes'the length, 2/Sv, and 4/Sv values for each of these
reaches. Table 2 shows tiiat for each reach, the reach length is less tiian the 2/Sv value (and
naturally also less than 4/Sv). Therefore, the grade control spacing in each of tiie tiiree reaches is
less dian 2/Sv and each reach is witiiin Category A on Checklist 2.
Study Reach Reach Length, ft 2/Sv, ft 4/Sv, ft
E5 250 713 1,426
E6 284 745 1,491
E7 603 1,099 2,198
Tabie 2. Grade Control Spacing Data
The Screening Index Threshold is a probability diagram tiiat depicts tiie risk of incising or
braiding based on the potential stream power of die valley relative to the median particle
diameter. The threshold is based on regional data from Dr. Howard Chang of Chang Consultants
and others. The probability diagram is based on dso as well as the Screening Index determined in
the initial desktop analysis (see Appendix A), dso is derived from field conditions. As discussed
above, the equivalent grain size for the densely-vegetated channels in Reaches El through E4,
E8, and Wl through W4 is at least 64 mm. The Screening Index Threshold diagram shows that
the 50 percent probability of incising or braiding for a dso of 64 mm has an index of at least
0.101 (in red rectangle on diagram). The Screening Index for these nine reaches calculated in
Appendix A varies from 0.009 to 0.039. Since each reach's Screening Index value is less than
the 50 percent value. Reaches El through E4, E8, and Wl through W4 fall witiiin Category A.
For Reaches E5 through E7, their Dso value was entered onto the Screening Index Threshold
graph. As mentioned above, a pebble count determined that the Dso for each of these reaches is
11 ram. Plotting 11 mm on tiie graph corresponds to a 50 percent Screening Index value of
0.038. The Screening Index calculated in Appendix A for the three reaches varies from 0.011 to
0.023. Since each reach's Screening Index value is less than the 50 percent value, Reaches E5,
E6, and E7 fall wdthin Category A.
The overall vertical rating is determined from the Checklist 1, Checklist 2, and Mobility Index
Threshold results. Tlie scoring is based on the following values:
Category A = 3, Category B = 6, Category C = 9
The vertical rating score for each of the twelve reaches is based on these values and tiie equation:
10
Vertical Rating = [(armoring x grade control)"^ x screening index score]^'^
= [(6 X 3)"^ X 3f'^ (Note: each of the twelve reaches has similar values)
= 3.6
Since the vertical rating is less than 4.5, each reach has a low vertical susceptibility to erosion.
Lateral Stability
The purpose of the lateral decision tree (Figure 6-5 from County of San Diego HMP included in
Figure 31) is to assess the state of the channel banks with a focus on the risk of widening.
Channels can widen frora either bank failure or through fluvial processes such as chute cutoffs,
avulsions, and braiding. Widening through fluvial avulsions/active braiding is a relatively
straightforward observation. If braiding is not already occurring, the next logical step is to assess
the condition of the banks. Banks fail through a variety of mechanisms; however, one of the most
important distinctions is whether they fail in mass (as many particles) or by fluvial detachment of
individual particles. Although much research is dedicated to the combined effects of weakening,
fluvial erosion, and mass failure, SCCWRP found it valuable to segregate bank types based on
the inference of the dominant failure mechanism (as the management approach may vary based
on the dominant failure mechanism). A decision tree (Form 4 in Appendix B) is used in
conducting die lateral susceptibility assessment. Definitions and photographic examples are also
provided below for terms used in the lateral susceptibility assessment.
The first step in the decision tree is to detemiine if lateral adjustraents are occurring. The
adjustments can take the form of extensive mass wasting (greater than 50 percent of the banks
are exhibiting planar, slab, or rotational failures and/or scalloping, undermining, and/or tension
cracks). The adjustraents can also involve extensive fluvial erosion (significant and frequent
bank cuts on over 50 percent of the banks). Neither mass wasting nor extensive fluvial erosion
was evident within any of the reaches during a field investigation. The banks are intact in the
photographs included in the figures. Due to the dense vegetation in most areas, photographs
representative of the banks were difficult to take. Nonetheless, the dense vegetation supports the
absence of large lateral adjustments.
The next step in the Form 4 decision tree is to assess the consolidation of tiie bank material. The
banks were moderate to well-consolidated. This determination was raade because the banks were
difficult to penetrate with a probe. In addition, the banks showed limited evidence of crumbling
and were composed of well-packed particles.
Forra 6 (see Appendix B) is used to assess the probability of raass wasting. Form 6 identifies a
10, 50, and 90 percent probability based on the bank angle and bank height. The 2-foot contour
interval topographic mapping indicates that the average natural bank angle is no greater than 2 to
1 (horizontal to vertical) or 26.6 degrees in any of the reaches. Form 6 shows that the probably of
mass wasting and bank failine has less than 10 percent risk for a 26.6 degree bank angle or less
regardless of the bank height.
The fmal two steps in the Form 4 decision tree are based on the braiding risk determined frora
the vertical rating as well as the Valley Width Index (VWI) calculated in Appendix A. If the
11
vertical rating is high, the braiding risk is considered to be greater than 50 percent. Excessive
braiding can lead to lateral bank failure. For all 12 study reaches, the vertical rating is low, so the
braiding risk is less than 50 percent. Furthermore, a VWI greater than 2 represents channels
unconfined by bedrock or hillslope and, hence, subject to lateral migration. The VWI
calculations in the spreadsheet in Appendix A show that the VWI for each reach is less than 2.
From the above steps, the lateral susceptibility rating is low for each of the twelve study reaches
(red circles are included on the Form 4: Lateral Susceptibility Field Sheet decision tree in
Appendix B showing the decision path). A review of aerial photographs confirms a lack of
braiding or lateral migration throughout the natural channels.
CONCLUSION
The SCCWRP chaimel screening tools were used to assess the downstreara channel
susceptibility for the Rancho Costera and associated El Camino Real Widening projects being
designed by O'Day Consultants, Inc. The project runoff will ultimately be collected by a series
of proposed and/or existing storm drain systems that outlet into unnamed natural channels at
various locations along the easterly and westerly portions of the developments. Each outlet is a
point of compliance. Based on die points of compliance, the unnamed natural channels were
assessed from the upstream-most POCs to either the confluence with Agua Hedionda Creek or
the concrete-lined Kelly Drive trapezoidal channel (domain of analysis). The assessment was
performed based on office analyses and field work. The resuhs indicate a low susceptibility for
vertical and lateral chaimel erosion for the entire study area.
The HMP requires tiiat these results be compared with the critical stress calculator results
incorporated in tiie County of San Diego's BMP Sizing Calculator. The BMP Sizing Calculator
critical stress results are included in Appendix B for all twelve reaches. Based on these values,
the critical stress results retumed a low susceptibility to erosion. Therefore, the SCCWRP
analyses and critical stress calculator demonstrate that the project can be designed assuming a
low susceptibility, i.e., O.5Q2.
The SCCWRP results are consistent with the physical condition of the natural channel within the
domain of analysis, which is moderately to densely-vegetated throughout. None of tiie twelve
study reaches exhibit signs of extensive, ongoing erosion.
12
Figure 1. Looking Downstmim lowariU Reach Kl ftom I'pper End
Figure 2. Looking Upsd eam towsrJs Reach Fl from Midpoint
13
!'ignrt Looking Downstream cowards Reach El frora Midpoinl
Figure 4, Loolujiie lipstream towards Reach El from Lower End
14
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Figure 5- Looking Downstream towards Rcuch EZ from Lpper End
F^ure fi. Looking IJpsfreHm (owards Reach E2 fmm Midponil
15
Figure 9. Looking Easterly towards Reach E4
Figure 10. Looking Upstream towards Reacli E4rroni Lower End
17
L:
lignrc 11. Looking Downstream towards Reach E5 from Upper Fnd
Figure 12. Looking Upstream towards Reach E5 from Lowtr End
IS
Figure 13. Looking Southeasterly towards Reaches E5, E6, and L7
11 pJIOVyHIIVff
Figure 14. Looking Upstroam towards Reach E6 from El Camino Real
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Figure 15. Looking Downslream towards Reach E7 from Upper End
Figure 16, Looking Westerly towards Reach E7
20
Figure 17. Looking Southeasterly towards Reach ES and Agua Hedionda Creek
Figure IS. Looking Downstream towards Reach W'l frnm Upper End
21
Figure 19. Looking Upstream tovyards Reach Wl from Lower End
Figure 20. Looking Downstream towards Reach W2 from Upper End
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Figure 21. Looking Upstream towards Reach W2 from Lower End
Figure 22- Looking Downstream towards Keach WJ from flpper End
23
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APPENDIX A
SCCWRP INITIAL DESKTOP ANALYSIS
SCCWRP FORM 1 ANALYSES
Area Mean Annual Precip. Valley Slope Valley Width 10-Year Flow 10-Year Flow
Reach A, sq. mi. P, inches Sv, m/m Wv, m QlOcfs, cfs QIC, cms
El 0.2400 13.3 0.0289 6.1 39 1.1
E2 0.0731 13.3 0.0551 1.5 14 0.4
E3 0.0732 13.3 0.0369 1.5 14 0.4
E4 0.1272 13.3 0.0247 8.5 22 0.6
E5 0.3963 13.3 0.0092 11.0 60 1.7
E6 0.3964 13.3 0.0088 4.6 60 1.7
E7 4.6800 13.3 0.0060 16.8 511 14.5
E8 5.1100 13.3 0.0091 25.9 552 15.6
Wl 0.0054 13.3 0.0448 2.4 1 0.04
W2 0.8078 13.3 0.0191 6.1 111 3.1
W3 1.1157 13.3 0.0127 17.7 147 4.2
W4 1.2688 13.3 0.0183 4.9 164 4.6
10-Year Screening Index Reference Width Vailey Width Index
Reach INDEX Wref, m VWI, m/m
El 0.030 7.3 0.84
E2 0.034 4.6 0.33
E3 0.023 4.6 0.33
E4 0.020 5.7 1.50
E5 0.012 8.8 1.25
E6 0.011 8.8 0.52
E7 0.023 22.5 0.74
E8 0.036 23.3 1.11
Wl 0.009 1.7 1.42
W2 0.034 11.5 0.53
WB 0.026 13.0 1.36
W4 0.039 13.7 0.36
PRECIPITATION
FROM COONTV BMP
SIZING CAUCUtATOR
Figure 25. Dense Vegeiation within Middle uf Reach W4
Figure 26. Looking Upstream toivards Reach W4 from Lower End al Conerete-Lined Kelly Dr- Channel
25
Figure 27. Gravelometer within Reach ES
Figure 2S. Gravelometer within Reach E6
26
LOW
tFtitf mmtdi) Dedioct tmk
iMAiMon ifl ifioi ccnd*gn
< No mdenM cf etwitt
tarmMIIKI / <Wl*IW)«
*F>iiyeaifliiM.ili(se«)r
connKM ID NIMte MUt-t
lAt£FlAUV*OJUeTABUE? >
VES <A(«LA1ER*l \
ADJUSTMEffTB >
OOCURBIWST /
VE8
1
MO
Nooe. or Durad oifir faniad ID iMMxIt md ooMttlaloni
1
MASS WASTING OR
EXTEKSrVE Furm.
CUTCFFFORKKnON
r
MED
vmst
FigiavS-S. Ln^KntChmndSusceptMiSify
Figure 31. SCCWRP Lateral Channel Susceptibility Matrix
29
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I APPENDIXA
I SCCWRP INITIAL DESKTOP ANALYSIS
FORM 1: INITIAL DESKTOP ANALYSIS
Complete all shaded sections.
IF required at muitipie locations, circle one of the following site types:
Applicant Site / Upstream Extent / Downstream Extent
Location: Latitude: 33.154 Longitude: -117.3040
Description (river name, crossing streets, etc.): RanchO Costera (north Of El CamlnO
Real between Tamarack Ave, and Cannon Rd.) and El Camino Real widening.
GIS Parameters: The international System of Units (SI) is used throughout the assessment as the field
standard and for consistency with the broader sdentific community. However, as the singular exception, US
Customary units are used for contributing drainage area (A) and mean annual precipitation (P) to apply regional flow
equations after the USGS. See SCCWRP Technical Report 607 for example measurements and "Screening Tool
Data Entry.xls" for automated calculations.
Form 1 Table 1. Initial desktop analysis in GIS.
Symbol Variable Description and Source Value
a> 0} c
-F e % x: 0) Q. m
2 "a
5 Q. c
in
I?
Wv
Area
(mi=)
Mean annual
precipitation
(in)
Contributing drainage area to screening location via published
Hydrologic Unit Codes (HUCs) and/or i 30 m National Elevation Data
(NED), USGS seamless server
Area-weighted annual precipitation via USGS delineated polygons using
records from 1900 to 1960 (which was more significant in hydrologic
models than polygons delineated from shorter record lengths)
Valley slope
(m/m)
Valley width
(m)
Valley slope at site via NED, measured over a relatively homogenous
valley segment as dictated by hillslope configuration, tributary
confluences, etc, over a distance of up to ~500 m or 10% of the main-
channel length from site to drainage divide
Valley bottom width at site between natural valley walls as dictated by
dear breaks in hillslope on NED raster, irrespective of potential
armoring from floodplain encroachment, levees, etc. (imprecise
measurements have negligible effect on rating in wide valleys where
VWI is » 2, as defined in lateral decision tree)
See attached
Form 1 table
on next page
for calculated
values for each
reach.
Form 1 TabI e 2. Simptif ied peak flo w, screening index, and valley width index. Values for this
table should be calculated in the sequence shown in this table, using values from Form 1 Table 1.
Symbol Dependent Variable Equation Required Units Value
QlOcfs 10-yr peak flow (ft'/s) Qiocts=18.2*A'""*P''" A (mi^)
P (in)
Qio* (ft'/s) Qio 10-yr peak flow (m'/s) Qio = 0.0283 * Qiocfs
A (mi^)
P (in)
Qio* (ft'/s) See attached
Fonm 1 table
INDEX
w„,
10-yr screening index (m^^/s°^)
Reference width (m)
INDEX = Sv*Qio ° ^
Wref =6.99 •Qio"'"*
Sv (m/m)
Qio (m'/s)
Qio (m'/s)
on next page
for calculated
values for each
VWI Valley width index (m/m) VWI = WvWref Wv(m)
W,e( (m) reach.
(Sheet 1 of 1)
B-3
SCCWRP FORM 1 ANALYSES
Area Mean Annual Precip. Valley Slope Valley Width 10-Year Flow 10-Year Flow
Reach A, sq. mi. P, inches Sv, m/m Wv, m QlOcfs, cfs QIO, cms
El 0.2400 13.3 0.0289 6.1 39 1.1
E2 0.0731 13.3 0.0551 1.5 14 0.4
E3 0.0732 13.3 0.0369 1.5 14 0.4
E4 0.1272 13.3 0.0247 8.5 22 0.6
E5 0.3963 13.3 0.0092 11.0 60 1.7
E6 0.3964 13.3 0.0088 4.6 60 1.7
E7 4.6800 13.3 0.0060 16.8 511 14.5
E8 5.1100 13.3 0.0091 25.9 552 15.6
Wl 0.0054 13.3 0.0448 2.4 1 0.04
W2 0.8078 13.3 0.0191 6.1 111 3.1
W3 1.1157 13.3 0.0127 17.7 147 4.2
W4 1.2688 13.3 0.0183 4.9 164 4.6
10-Year Screening Index Reference Width Valley Width Index
Reach INDEX Wref, m VWI, m/m
El 0.030 7.3 0.84
E2 0.034 4.6 0.33
E3 0.023 4.6 0.33
E4 0.020 5.7 1.50
E5 0.012 8.8 1.25
E6 0.011 8.8 0.52
E7 0.023 22.5 0.74
E8 0.036 23.3 1.11
Wl 0.009 1.7 1.42
W2 0.034 11.5 0.53
W3 0.026 13.0 1.36
W4 0.039 13.7 0.36
- Sizing Calculator
Define Drainage Basins
r.f- Cnn'nrl
Map data provided by OpenStreetMap
Map Details
Basm Agua Hedionda Watershed Project Ranch Costera & El Camino Real Widening
Manage Your Basins
Create a new Basin by clicking the New Ixjtton and scrol down lo view
er«ry. /ytematively, select an exisfing Basin from tabte and view
properties t>etow. Click Edft button to change Basin prop«ties then
press Save to commit changes.
Agua Heiionda Waterahad
Dssign Goal:
Point of Compliancs:
Projact Basin Arsa (ac): j<4i^^«)%i ^^vs. J
RainfollBasin: |OMpBSani',i»vft4,.\'. vj I Msan Annual PrsclpMon (In): tjf A j
MEAN ANNUAL PRECIPITATION FROM COUNTY BMP SIZING CALCULATOR
PEBBLE COUNT
# Reach E5 Diameter, mm Reach E6 Diameter, mm Reach E7 Diar
1 2 2 2
2 2 2 2
3 2 2 2
4 2 2 2
5 2 2 2
6 2.8 2 2
7 2.8 2 2
8 2.8 2 2
9 2.8 2 2.8
10 2.8 2.8 2.8
11 4 2.8 2.8
12 4 2.8 2.8
13 4 2.8 2.8
14 4 2.8 2.8
15 4 2.8 2.8
16 4 2.8 2.8
17 4 2.8 4
18 4 2.8 4
19 4 4 4
20 4 4 4
21 4 4 4
22 4 4 4
23 4 4 4
24 5.6 4 4
25 5.6 4 4
26 5.6 4 4
27 5.6 4 4
28 5.6 4 4
29 5.6 5.6 5.6
30 5.6 5.6 5.6
31 5.6 5.6 5.6
32 5.6 5.6 5.6
33 5.6 5.6 5.6
34 5.6 5.6 5.6
35 8 5.6 5.6
36 8 5.6 8
37 8 5.6 8
38 8 5.6 8
39 8 5.6 8
40 8 5.6 8
41 8 5.6 8
42 8 5.6 8
43 8 8 8
44 8 8 8
I
i # Reach E5 Diameter, mm Reach E6 Diameter, mm Reach E7 Dian
45 8 8 11
46 8 8 11
47 8 8 11
48 11 8 11
49 11 11 11
SO 11 11 11
51 11 11 11
52 11 11 11
53 11 11 11
54 11 11 11
55 11 11 11
56 11 11 11
57 11 11 16
58 11 11 16
59 11 11 16
60 11 11 16
61 11 11 16
62 11 11 16
63 11 11 16
64 11 11 16
65 11 16 16
66 11 16 16
67 16 16 16
68 16 16 16
69 16 16 16
70 16 16 16
71 16 16 16
72 16 16 16
73 16 16 16
74 16 16 16
75 16 16 16
76 16 16 16
77 16 16 16
78 16 16 16
79 16 16 16
80 16 16 16
81 16 16 16
82 16 16 16
83 16 16 16
84 16 16 16
85 16 16 22.6
86 16 16 22.6
87 16 16 22.6
88 16 16 22.6
89 16 22.6 22.6
90 16 22.6 22.6
# Reach E5 Diameter, mm Reach E6 Diameter, mm Reach E7 Dianr
91 22.6 22.6 22.6
92 22.6 22.6 22.6
93 22.6 22.6 22.6
94 22.6 22.6 22.6
95 22.6 22.6 32
96 22.6 22.6 32
97 22.6 22.6 32
98 22.6 32 32
99 32 32 32
100 32 32 64
EXCERPT FROM FEMA' MAY 16, 2012, "FLOOD INSURANCE STUDY, SAN DIEGO, COUNTY"
SHOWING AGUA HEDIONDA CREEK DRAINAGE AREA
TABLE 8: SUMMARY OF PEAK DISCHARGES
Flooding Source and Location '
Adobe Creek
2,200 Feet Upstream of Peet Lane
Agua Hedionda Creek
0.67
At Confluence with Buena Creek
2,200 Feet Upstream of Rancho Carlsbad Drive
Upstream of Calavera Creek
At El Camino Real
Alvarado Creek
At Lake Shore Drive
At Interstate 8, Near Trailer Park
At Interstate 8, Near Murray Boulevard
Upstream of Murray Creek
Downstream of Murray Creek
At Downstream Side of College Avenue
Upstream of Tributary Channel
Downstream of Tributary Channel
6.3
16.5
17.3
23.8
4.6
5.3
5.7
6.3
10.1
11.4
12.1
13.4
Peak Discharges (cubic feet per second)
10% Annual-
375
2% Annual-
., Chance
1% Annual-
1,600
1,200
1,300
1,400
1,600
1,700
2,100
2,300
2,600
485
4,800
2,000
2,200
2,400
2,600
2,900
3,400
3,700
4,300
560
7,000
7,810
8,080
9,850
2,300
2,500
2,700
3,000
3,300
3,900
4,300
4,800
0.2% Annnal-
;,Cl4ance
710
15,500
3,000
3,200
3,500
3,800
4,200
5,000
5,400
6,100
• Data Not Available
68
EXCERPTS FROM O'DAY CONSULTANTS'
"RANCHO COSTERA DRAINAGE STUDY".
SEE MAP POCKET FOR WORK MAP.
APPENDIX 6
100 Yr. Proposed Hydrologic Calculations
Basin <H'
(See Exhibit 'K')
11
IVIaximum flow rates at confluence using above data:
37.976 22.996 40.432 49.662
Area of streams before confluence:
5.550 1.210 2.000 26.600
Results of confluence:
Total flow rate = 49.662(CFS)
Time of concentration = 20.000 min.
Effective stream area after confluence = 35.360(Ac.)
++++++++++++++++
Process from Point/Station 210.000 to Point/Station 214.000
**** IRREGtJIiAR CHANNEL FLOW TRAVEL TIME ****
Estimated mean flow rate at midpoint of channel = 53.019(CFS)
Depth of flow = 1.519(Ft.), Average velocity = 7.657(Ft/s)
******* Irregular Channel Data ***********
Information entered for subchannel number 1 :
Point number 'X' coordinate 'Y' coordinate
1 0.00 10.00
2 30.00 0.00
3 60.00 10.00
Manning's 'N' friction factor - 0.035
Sub-Channel flow = 53.019(CFS)
• • flow top width = 9.115(Ft.)
' ' velocity= 7.657(Ft/s)
' ' area - 6.924(Sq.Ft)
' ' Froude number = 1.548
Upstream point elevation = 142.000(Ft.)
Downstream point elevation = 70.000(Ft.)
Flow length - 1430.000 (Pt.)
Travel time = 3.11 min.
Time of concentration = 23.11 min.
Depth of flow = 1.519(Ft.)
Average velocity = 7.657(Ft/s)
Total irregular channel flow = 53.019(CFS)
Irregular channel normal depth above invert elev. = 1.519(Ft.)
Average velocity of channel (s) => 7.657 (Ft/s)
Adding area flow to channel
Rainfall intensity (I) = 2.552(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Perraanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value =• 0.350
Rainfall intensity = 2.552(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
{Q=KCIA) is C = 0.471 CA - 22.060
Subarea runoff = 6.634 (CFS) for 11.500(Ac.)
Total runoff = 56.296 (CFS) Total area = 46.860(Ac.) Reacll E3
Depth of flow = 1.554(Ft.), Average velocity = 7.773(Ft/s)
Note: Reach E2 = 46.86 - 0.1 = 46.76 Acres
++++++++++++++-i-++++++++++++++++++++++++++++++++-f+++-i-+++++++++++++
Process from Point/Station 214.000 to Point/Station 216.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 70.000(Ft.)
Downstream point/station elevation = 60.000(Ft.)
Pipe length = 250.00(Ft.) Slope = 0.0400 Manning's N = 0.015
No. of pipes = 1 Required pipe flow = 56.296(CFS)
Given pipe size = 30.00 (In.)
Calculated individual pipe flow = 56.296(CFS)
Norraal flow depth in pipe = 20.16(In.)
Flow top width inside pipe = 28.17(In.)
Critical Depth = 28.38(In.)
Pipe flow velocity = 16.06(Ft/s)
Travel tirae through pipe = 0.26 min.
Time of concentration (TC) = 23.37 min.
++++++++++++^•+++++++++++++++++++++++++++++++++-^++++++++++^•++++^-++ +
Process from Point/Station 214.000 to Point/Station 216.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 46.860(Ac.)
Runoff frora this stream = 56.296(CFS)
Time of concentration = 23.37 min.
Rainfall intensity = 2.534(Xn/Hr)
Program is now starting with Main Stream No. 2
+++++++++++++++-!•++++++++++-^++++++++++++++++++++++++++++++++++-^++++
Process from Point/Station 218.000 to Point/Station 222.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Deciraal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[HIGH DENSITY RESIDENTIAL ]
(24.0 DU/A or Less )
Impervious value, Ai = 0.650
Sub-Area C Value = 0.710
Initial subarea total flow distance = 100.000(Ft.)
Highest elevation = 130.500(Ft.)
Lowest elevation = 128.700(Ft.)
Elevation difference = 1.800(Ft.) Slope = 1.800 %
Top of Initial Area Slope adjusted by User to 0.740 %
Bottom of Initial Area Slope adjusted by User to 0.740 %
8
' ' area = 30.066(Sq.Ft)
' ' Froude number = 1.057
Upstream point elevation » 60.000(Ft.)
Downstream point elevation = 42.000(Ft.)
Flow length = 600.000(Ft.)
Travel time = 3.07 min.
Time of concentration = 26.44 rain.
Depth of flow = 0.298(Ft.)
Average velocity = 3.260(Ft/s)
Total irregular channel flow = 97.999(CFS)
Irregular channel norraal depth above invert elev. = 0.298(Ft.)
Average velocity of channel(s) = 3.260(Ft/s)
+ + + + + + ++4 + ++-h++++++ + + + +++++++ + + ++ +++ + +++ +++-l- +++ ++4 + ++ + + + -l- + + + + + + + + + +
Process frora Point/Station 216.000 to Point/Station 2009.000
**** SUBAREA FLOW ADDITION ****
Rainfall intensity (I) = 2.340(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
The area added to the existing streara causes a
a lower flow rate of Q = 93.650(CFS)
therefore the upstream flow rate of Q = 97.999(CFS) is being used
Time of concentration = 26.44 rain.
Rainfall intensity = 2.340(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
{Q=KCIA) is C = 0.492 CA = 40.024
Subarea runoff = 0.000(CFS) for 4.850(Ac.)
Total runoff = 97.999(CFS) Total area = 81.430 (Ac.) Reach E4
+ +++ + + + + + +++ + + + + +++ + + + + +++ +++ + +++ ++++ + + + + +++ + + + + + + + +++ + + 4 + +++ ++-I- + +++ + +
Process from Point/Station 216.000 to Point/Station 2 009.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Streara nuraber: 1
Streara flow area = 81.430(Ac.)
Runoff from this streara = 97.999(CFS)
Time of concentration = 26.44 min.
Rainfall intensity = 2.340(In/Hr)
Program is now starting with Main Streara No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 254.000 to Point/Station 254,000
20
Area of streams before confluence:
114.250 19.180
Results of confluence:
Total flow rate = 163.679(CFS)
Time of concentration = 20.880 min.
Effective stream area after confluence = 133.430(Ac.)
+ ++-1- + ++++ ++++++++ ++4 + +++++ +++ + + + +++ + ++++ + +++ + ++++++++++ + + +++++++++++++
Process from Point/Station 272.000 to Point/Station 2009.000
**** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
Estimated mean flow rate at midpoint of channel = 163.727(CFS)
Depth of flow = 0.727(Ft.), Average velocity = 4.344(Ft/s)
******* Irregular Channel Data ***********
Information entered for subcharmel nuraber 1 :
Point nuraber 'X' coordinate 'Y' coordinate
1 0.00 10.00
2 30.00 0.00
3 80.00 0.00
4 100.00 10.00
Manning's 'N' friction factor = 0.035
Sub-Channel flow = 163.728(CFS)
' ' flow top width - 53.637(Ft.)
' ' velocity- 4.344(Ft/s)
• • area = 37.692(Sq.Ft)
' • Froude nuraber = 0.913
Upstreara point elevation = 69.000(Ft.)
Downstream point elevation = 42.000(Ft.)
Flow length = 1600.000(Ft.)
Travel time = 6.14 rain.
Time of concentration = 27.02 min.
Depth of flow = 0.727(Ft.)
Average velocity = 4.344(Ft/s)
Total irregular channel flow = 163.727(CPS)
Irregular channel normal depth above invert elev. = 0.727(Ft.)
Average velocity of channel(s) = 4.344(Ft/s)
Adding eirea flow to channel
Rainfall intensity (I) = 2.307(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Deciraal fraction soil group D = 1.000
[UNDISTURBED NATXJIRAL TERRAIN ]
(Permanent Open Space )
Irapervious value, Ai - 0.000
Sub-Area C Value = 0.350
The area added to the existing stream causes a
a lower flow rate of Q = 151.902(CFS)
therefore the upstream flow rate of Q = 163.679(CFS) is being used
Rainfall intensity = 2.307(In/Hr) for a 100.0 year storm
36
I
I
i Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.429 CA = 65.833
Subarea runoff = 0.000(CFS) for 20.180(Ac.)
Total runoff = 163.679(CFS) Total area = 153.6lO{Ac.} Reach El
Depth of flow = 0.727(Ft.), Average velocity = 4.343(Ft/s)
+++++-!•++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 272.000 to Point/Station 2009.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Streara flow area = 153.610(Ac.)
Rtmoff from this stream = 163.679(CFS)
Time of concentration = 27.02 min.
Rainfall intensity = 2.307(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (rain) (In/Hr)
1 97.999 26.44 2.340
2 163.679 27.02 2.307
Qraax (1) =
1.000 * 1.000 * 97.999) +
1.000 * 0.979 * 163.679) + = 258.167
Qraax (2) =
0.986 * 1.000 * 97.999) +
1.000 * 1.000 * 163.679) + = 260.317
Total of 2 main streams to confluence:
Flow rates before confluence point:
97.999 163.679
Maximura flow rates at confluence using above data:
258.167 260.317
Area of streams before confluence:
81.430 153.610
Results of confluence:
Total flow rate = 260.317(CFS)
Tirae of concentration = 27.019 rain.
Effective stream area after confluence = 235.040(Ac.!
+-i-+++++++++++++++++-t-+++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 2009.000 to Point/Station 2010.000
**** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
Estimated mean flow rate at midpoint of channel = 260.342(CFS)
Depth of flow = 0.680(Ft.), Average velocity = 3.738(Ft/s)
******* Irregular Channel Data ***********
37
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 24.726(CFS)
Normal flow depth in pipe = 13.66(In.)
Flow top width inside pipe = 20.02(In.)
Critical depth could not be calculated.
Pipe flow velocity - 14.92(Ft/s)
Travel tirae through pipe = 0.78 rain.
Time of concentration (TC) = 25.51 min.
Process frora Point/Station 2013.000 to Point/Station 2010.000
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal streara number 2
Stream flow area = 12.650(Ac.)
Runoff from this stream = 24.726(CFS)
Time of concentration = 25.51 rain.
Rainfall intensity = 2.394(In/Hr)
Sununary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 260.317 29.25 2.192
2 24.726 25.51 2.394
Qmax(1) =
1.000 * 1.000 * 260.317) +
0.916 * 1.000 * 24.726) + = 282.955
Qraax(2) =
1.000 * 0.872 * 260.317) +
1.000 * 1.000 * 24.726) + - 251.779
Total of 2 streams to confluence:
Flow rates before confluence point:
260.317 24.726
Maxiraum flow rates at confluence using above data:
282.955 251.779
Area of streams before confluence:
240.950 12.650
Results of confluence:
Total flow rate = 282.955(CFS)
Time of concentration = 29.249 min.
Effective stream area after confluence = 253.600 (Ac.)
Process from Point/Station 2010.000 to Point/Station 2015.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 35.300(Ft.)
Downstream point/station elevation = 34.500(Ft.)
Pipe length = 40.00(Ft.) Slope = 0.0200 Manning's N = 0.013
41
I
I
No. of pipes = 1 Required pipe flow = 282.955(CFS)
Given pipe size = 30.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
95.622(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 19.029(Ft.)
Minor friction loss = 77.393(Ft.) K-factor = 1.50
Critical depth could not be calculated.
Pipe flow velocity = 57.64(Ft/s)
Travel time through pipe = 0.01 min.
Tirae of concentration (TC) = 29.26 min.
End of coraputations, total study area = 253.600 (Ac.) Reach E5
Note: Reach E6 = 253.6 + 0.1 = 253.7 Acres
42
APPENDIX 4
100 Yr. Proposed Hydrologic Calculations
Basin 'E-F'
(See Exhibit 'K')
I
i Process from Point/Station 5000.000 to Point/Station 5000.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream ntimber: 1
Stream flow area = 509.400(Ac.)
Runoff from this stream = 512.740(CFS)
Time of concentration = 31.46 min.
Rainfall intensity = 2.092(In/Hr)
Program is now starting with Main Stream No. 2
+++ +++++++ +++++++ +++-I-++-I- +++ ++++++-I-+ +++ +++++++ + H
Process from Point/Station 5002.000 to Point/Station 5004.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 100.000(Ft.)
Highest elevation = 180.000(Ft.)
Lowest elevation = 130.000(Ft.)
Elevation difference = 50.000(Ft.) Slope = 50.000 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.34 minutes
TC = [1.8*(l.l-C)*distance(Ft.)'^.5)/(% slope"(l/3)]
TC = [1.8*(l.l-0.3500)*( 100.000".5)/( 30.000^(1/3)]= 4.34
Calculated TC of 4.345 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 6.850(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.240(CFS)
Total initial stream area = 0.100(Ac.)
+++ +++ ++++++ + +++ + +++ + -I-++ +++ + +++ +++++++ ++++++++++-I-+++-H ++++++ + +++++
Process from Point/Station 5004.000 to Point/Station 5006.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 130.000(Ft.)
Downstreara point elevation = 63.000(Ft.)
Channel length thru subarea = 700.000(Ft.)
Channel base width = 1.000 (Ft.)
Slope or 'Z' of left channel bank = 2.000
Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rat:e at midpoint of channel = 3.659 (CFS)
Manning's 'N' = 0.035
Maximum depth of channel = 2.000(Pt.)
Flow{q) thru subarea = 3.659(CFS)
Depth of flow = 0.391(Ft.), Average velocity = 5.259(Ft/s)
Channel flow top width = 2.563(Ft.)
Flow Velocity = 5.26(Ft/s)
Travel time = 2.22 min.
Time of concentration = 6.55 min.
Critical depth = 0,531(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 5.748(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Irt¥)ervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 5.748(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 1.214
Subarea runoff = 6.741(CFS) for 3.370(Ac.)
Total runoff = 6.981 (CFS) Total area = 3.470(Ac.) Reach W1
Depth of flow = 0.538(Ft.), Average velocity = 6.247(Ft/s)
Critical depth = 0.734(Ft.)
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Process from Point/Station 5006.000 to Point/Station 5008.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 63.000(Ft.)
Downstream point/station elevation = 51.800(Ft.)
Pipe length = 68.00(Ft.) Slope = 0.0176 Manning's N = 0.013
No. of pipes = 1 Reguired pipe flow = 6.981(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 6.981(CFS)
Normal flow depth in pipe = 9.00(In.)
Flow top width inside pipe = 18.00 (In.)
Critical Depth = 12.28(In.)
Pipe flow velocity = 7.90(Ft/s)
Travel time through pipe = 0.14 min.
Time of concentration (TC) = 6.71 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5008.000 to Point/Station 5000.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 61.800(Ft.)
Downstream point elevation = 57.000(Ft.)
I
Depth of flow = 0.299(Ft.), Average velocity = 1.911(Ft/s)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 8.129 (Ft.)
Flow velocity = 1.91(Ft/s)
Travel time = 3.14 min. TC = 9.39 min.
Adding area flow to street
Rainfall intensity (I) = 4.562(In/Hr) for a 100,0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[MEDIUM DENSITY RESIDENTIAL ]
(7.3 DU/A or Less )
Inpervious value, Ai = 0.400
Sub-Area C Value = 0.570
Rainfall intensity = 4.562(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.570 CA = 1.180
Svibarea runoff = 5.044 (CFS) for 1.970 (Ac.)
Total rimoff = 5.382 (CFS) Total area = 2.070 (Ac.)
Street flow at end of street = 5.382(CFS)
Half street flow at end of street = 2.691(CPS)
Depth of flow = 0.348(Ft.), Average velocity = 2.200(Ft/s)
Flow widtJi (from curb towards crown)= 10.586(Ft,)
++++-h++++++++++++++++++++++++++++++-i-+++++++++++++++++++++++++++++
Process from Point/Station 5017.000 to Point/Station 5014.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 135.500(Ft.)
Downstream point/station elevation = 79.050(Ft.)
Pipe length = 510.00(Ft.) Slope = 0.1107 Mcuining's N = 0.013
No. of pipes = 1 Required pipe flow = 5.382(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 5.382(CFS)
Normal flow depth in pipe = 4.78(In.)
Flow top width inside pipe = 15.89(In.)
Critical Depth = 10.73(In.)
Pipe flow velocity = 14.33(Ft/s)
Travel time through pipe = 0.59 min.
Time of concentration (TC) = 9.98 min.
+ + +++-l- + +-++++++++++++++++4-+ + + +++ +++++++ + ++++++++++++++-t-4-++-t- +++
Process from Point/Station 5017.000 to Point/Station 5014.000
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Streara number: 2 in normal stream number 2
Stream flow area = 2.070(Ac.)
Runoff from this streara = 5.382(CFS)
Time of concentration = 9.98 min.
Rainfall intensity = 4.385(In/Hr)
Summary of stream data:
I
stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 4 498 5 .73 6.276
2 5 382 9 98 4.385
Qmax(l) =
1. 000 * 1. 000 * 4. 498) +
1. 000 * 0. 574 * 5. 382) + = 7 .586
Qmax(2) =
0. 699 * 1. 000 * 4. 498) +
1. 000 * 1. 000 * 5. 382) + = 8 .526
Total of 2 streams to confluence:
Flow rates before confluence point:
4.498 5.382
Maximum flow rates at confluence using above data:
7.586 8.526
Area of streams before confluence:
2.040 2.070
Results of confluence:
Total flow rate = 8.526(CFS)
Time of concentration = 9.984 min. Reach W2
Effective stream area after confluence = 4.110(Ac.)
(easterly subarea)
Total Area of Reach W2 is northerly + easterly subarea.
+++++++++++++-(-+++++++++++++++++++++++-1-+++?+++++++++++++++++++
Process from Point/Station 5014.000 to Point/Station 5018.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 79.050(Ft.)
Downstrecim point/station elevation = 60.000 (Ft.)
Pipe length = 96.00(Ft.) Slope = 0.1984 Marming's N = 0.013
No. of pipes = 1 Required pipe flow = 8.526(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 8.525(CFS)
Normal flow depth in pipe = 5.20(In.)
Flow top width inside pipe = 16.32(Xn.)
Critical Depth = 13.57(In.)
Pipe flow velocity = 20.14(Ft/s)
Travel time through pipe = 0.08 min.
Time of concentration (TC) = 10.06 min.
++++++++++++++++-H- + + + +++ + +++ + +-l-++++ + -h + ++++ ++4-++++ + ++H
Process from Point/Station 5018.000 to Point/Station 5010.000
**** IMPROVED CHANNEL TRAVEL TIME ''""**
Upstream point elevation = 60.000(Ft.)
Downstream point elevation = 51.000(Ft.)
Channel length thru subarea = 460.000(Ft.)
Channel base width = 1.000(Ft.)
Slope or 'Z' of left chaimel bank = 2.000
10
I
I
I Sub-Channel flow = 22.805(CFS)
' ' flow top width = 7.226(Ft.)
velocity= 3.494(Ft/s)
area = 6.527(Sq.Ft)
' ' Froude number = 0.648
Instream point elevation = 43.620(Ft.)
Downstrecun point elevation = 42.000(Ft.)
Flow length = 180.000(Ft.)
Travel time = 0.86 min.
Time of concentration = 9.93 min.
Depth of flow = 1.807(Ft.)
Average velocity = 3.494(Ft/s)
Total irregular channel flow = 22.805(CFS)
Irregular channel normal depth above invert elev. = 1.807(Ft.)
Average velocity of channel(s) = 3.494(Ft/s)
++++++^.+^.+++++++++++-^+++++++++++^•+++++++++++++++++++++^-++-^-^+
Process from Point/Station 5050.000 to Point/Station 5034.000
**** CONFLUENCE OF MAIN STEIEAMS ****
The following data inside Main Stream is listed:
In Main Stream nuraber: 2
Stream flow area = 6.610(Ac.)
Runoff from this stream = 22.805(CFS)
Time of concentration = 9.93 min.
Rainfall intensity = 4.402(In/Hr)
Svunmary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 719.611 35.74 1.926
2 22.805 9.93 4.402
Qmax(l) =
1.000 * 1.000 * 719.611) +
0.438 * 1.000 * 22.805) + = 729.591
Qmax(2) =
1.000 * 0.278 * 719.611) +
1.000 * 1.000 * 22.805) + = 222.633
Total of 2 raain streams to confluence:
Flow rates before confluence point;
719.611 22.805
Maximum flow rates at confluence using above data:
729.591 222.633
Area of streams before confluence:
707.440 6.610
Results of confluence:
21
I
I
I
Total flow rate = 729.591(CFS)
Time of concentration = 35.742 min.
Effective stream area after confluence = 714.050(Ac.) Reach W3
+++++++++++-^-^+++++++++++++++++++-l-+++-^++++++++++-l•++++++++++++++
Process from Point/Station 5034.000 to Point/Station 5052.000
**** IMPROVED CHANNEL TRA'VEL TIME **** EXISTIHQ DOUBXJB B'Xi' RCB
Covered channel
Upstream point elevation = 42.000(Ft.)
Downstream point elevation = 40.000(Ft.)
Channel length thru subarea = 108.000 (Ft.) /-) , 7Z C-fs^
Channel base width = 16.000(Ft.) ^<00
Slope or "Z' of left channel bank = 0.000 ^ _ /7^//?.
Slope or 'Z' of right channel bank = 0.000 ' iS-'
Manning's 'N' = 0.015 - '^[^.O^ H <^ •
Maximum depth of charmel = 4.000(Ft.)
Flow{q) thru subarea = 729.591(CFS)
Depth of flow = 2.298(Ft.), Average velocity = 19.840(Ft/s)
Channel flow top width = 16.000(Ft.)
Flow Velocity = 19.84(Ft/s)
Travel time = 0.09 min.
Time of concentration = 35.83 min.
Critical depth = 4.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++-++++++++^
Process from Point/Station 5034.000 to Point/Station 5052.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 714.050(Ac.)
Runoff from this stream = 729.591(CFS)
Time of concentration = 35.83 min.
Rainfall intensity = 1.923(In/Hr)
Program is now starting with Main Stream No. 2
+ + ++++ +++++ + ++++ + + + ++-l-++++ + + + ++ + + + ++++++-(-+++4-++-(- + +-++++ ++++ + ++++ + +
Process from Point/Station 7 000.000 to Point/Station 7007.000
**** USER DEFINED FLOW INFORMATION AT A POINT
User specified 'C value of 0.700 given for subarea
Rainfall intensity (1) = 3.229(In/Hr) for a 100,0 year storm
User specified values are as follows:
TC = 16.05 min. Rain intensity = 3.23(In/Hr)
Total area = 72.820(Ac.) Total runoff = 163.030(CFS)
Process from Point/Station 7000.000 to Point/Station 7007.000
**** CONFLUENCE OF MAIN STREAMS ****
22
I
The following data inside Main Stream is listed:
In Main Stream nvimber: 2
Stream flow area = 72.820(Ac.)
Runoff from this stream = 163.030 (CFS)
Time of concentration = 16.05 min.
Rainfall intensity = 3.229(In/Hr)
Program is now starting with Main Stream No. 3
Process from Point/Station 8003.000 to Point/Station 7007.000
USER DEFINED FLOW INFORMATION AT A POINT ****
User specified 'C value of 0.900 given for subarea
Rainfall intensity (I) = 5.688(In/Hr) for a 100.0 year storm
User specified values are as follows:
TC = 6.67 min. Rain intensity. = 5.69 (In/Hr)
Total area = 2.450(Ac.) Total runoff = 13.200(CFS)
++-I-++++++++-K + +++++++++++++++++++ +++++++++++ + + +++ ++++++++++ +++++++
Process from Point/Station 8003,000 to Point/Station 7007.000
**** CONFLUENCE OF MAIN STREAMS ***'*
The following data inside Main Stream is listed:
In Main Stream number: 3
Stream flow area = 2.450(Ac.)
Runoff from this stream = 13.200(CFS)
Time of concentration = 6.67 min.
Rainfall intensity = 5.688(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 729.591 35.83 1.923
2 163.030 16.05 3.229
3 13.200 6.67 5.688
Qmax(1) =
1.000 * 1.000 * 729 .591) +
0.596 * 1.000 * 163 .030) +
0.338 * 1.000 * 13 .200) + = 831 .169
Qmax(2) =
1.000 * 0.448 * 729 .591) +
1.000 • 1.000 * 163 .030) +
0.568 * 1.000 * 13 .200) + = 497 .314
Qmax(3) =
1.000 * 0.186 * 729 .591) +
1.000 * 0.416 * 163 .030) +
1.000 * 1.000 * 13 .200) + = 216 .759
Total of 3 main streams to confluence:
23
Flow rates before confluence point:
729.591 153.030 13.200
Majcimum flow rates at confluence using above data:
831.169 497.314 216.759
Area of streams before confluence:
714.050 72.820 2.450
Results of confluence:
Total flow rate = 831.169(CFS)
Time of concentration = 35.833 min.
Effective stream area after confluence = 789.320(Ac.)
End of COT$>utations, total study area = 789.320 (Ac.)
This Is the area into the upper end of Reach W4. The totai area
tributary to Reach W4 is 789.32 acres pius the tributary area
downstream of El Camino Real, which was delineated from the
topographic mapping on the Study Area Exhibit and is 22.70 acres.
24
EXCERPTS FROM CHANG CONSULTANTS' "LOMR REQUEST FOR ROBERTSON'S RANCH"
SHOWING DRAINAGE AREA TRIBUTARY TO REACH E7 (4.68 ACRES) AND E8 (5.11 ACRES)
EKW IN OBIC mx EER SHXND
Tn^; IN mss, AREA IN SSUAFE MIIES
OffiRKITCN SWICN
EERK TBE CF AVEBfiGE EICW EOR MftXDlM EERIOD
ETDH EERK
e-mjR 24-fOJR 72-tCCR
BASIN MRXMJM TBE CF
APEA siao; MRX STRGE;
HTCSOGBATH AT
a 505. 10.25 249. 102. ,87
FOnED TO
504. 10.25 249. 102. 98. .87
335.64 10.25
FDUIED TO
a-C2 361. 11.00 235. 98. 95. .87
240.99 11.00
HYDRDGRAEH AT
C2 1519. 10.33 760. 311. 299. 2.72
2 CCMBDED AT
OIBINE 1831. 10.42 409. 394. 3.59
POUTED TO
EETCRIA 1348. 11.17 745. 291. 280. 3.59
218.76 11.17
BCUIED TO
C2-a 1325. 11.33 743. 290. 279. 3.59
100.24 11.33
reraCGPAPH AT
C3 475. 10.08 224. 91. .88
2 CCMBDED AT
OOCINE 1501. 11.17 879. 381. 367. 4.47
EOmD TO
EE3NBJB 971. 12.58 832. 381. 367. 4.47
76.38 12.58
DIVERSICN TO
DTVNCKTH 473. 12.58 421. 181. 174. 4.47
HnHXBSIH AT
Divo: 498. 12.58 411. 200. 193. 4.47
HM3BDGRAEH AT
C4 629. 10.42 314. 128. 123. 1.24
2 CCMBMD AT
907. 10.67 681. 328. 316. 5.71
KXJIED TO
C3S-Ba: 896. 10.83 680. 326. 314. 5.71
46.10 10.83
HYDBOGRRtH AT
RX 26. 10.00 12. 5. .05
2 CCMBINED AT
0C3OERL 909. 10.75 691. 331. 319. 5.76
HYEBDSyaH AT
RETDIV 473. 12.58 421. 181. 174. .00
BOUTED TO
KINOEt 473. 12.75 421. 179. 173. .00
40.37 12.75
HOTDOaEH AT
E1RC2 99. 10.08 46. 19. 18. •21 Reach E7 to here
2 CnBINED AT
BCK 497. 12.17 444. 198. 191. .21
ICnRaSflPH RT
EECH 198. 10.00 92. 38. 36. .43 Reach EB to here
2 OCMBBED AT
EX 8x8 549. 12.08 504. 236. 227. .63
BOOTED TO
NUBSEfor 545. 12.50 503. 236. 227. .63
35.34 12.50
*** tCRffil, EM) OF HEC-l ***
DRAINAGE AREA EXHIBIT FROM CHANG CONSULTANTS' LOMR
APPENDIX B
SCCWRP FIELD SCREENING DATA
Chapter 5. Open Channels
Table 5-13 Maximum Permissible Velocities for Lined and Unlined Channels
l^^aterial or Lining IVIaximum Permissible
Avttrage Velocity* (ft/sec)
Natural and Improved Unlined Channels
Fine Sand, Colloidal 150
Sandy Loam, Noncolloidal 1.75
Silt Loam, Noncolloidal 2.00
Alluvial Snts, Noncolloidal 2.00
Ordinary Rrm Loam..... 2.50
Volcanic Ash 2.50
Stiff Clay, Very Colloidal 3.75
Alluvial Silts, Collodal 3.75
Shales And Hardpans 6.00
Fine Gravel 2.50
Graded Loam To Cobbles When Noncolloidal 3.75
Giaded Sills To Cobbles When Colloidal 4.00
Coarse Gravel, Noncolloidal - 4.00
Cobttes And ShHigles - 5.00
Sandy Silt 2.00
Silty Clay 2.50
Clay - 6.00
Poor Sedimentary Rock 10.0
Fully-Lined Channels
Unreinforced Vegetation .............5.0
Reinforced Turf - 10.0
Loose Riprap per Table 5-2
Grouted Riprap 25.0
Gabions 15.0
Soil Cement 15.0
Concrete 35.0
• Maximum pemjiss/We veiodty listed here Is basic guideline; tngtter design vetocftes may be used, pmrided appropriate
lechnlcal documentatio-i tmm manufaoiurer.
San Diego County Drainage Design Manual Page 5-43
July 2005
Form 3 Suooort Materials
Form 3 Checklists 1 and 2, along Mvilh information recording in Form 3 Tabte 1,
are intended to support the decisions pathways illuslrated in
Form 3 Oueraii Vertical Rating tor Infermediate/Transitional Bed.
Form 3 Checklist 1: Armoring Potential
A A mm of coarse gravels and cobbles thai are lighlly packed wit^ <5%
surface malerial of diameler <2 mm
B InlermedJale to A and C or hardpan of unknown resistance, epdtial extent
{longitutTinal and depth), or unknown armoring potential due b surface
veneer covering gravel or coarser layer encountered with probe
C Gravels/cobbles lhal are loosely packed or >25% surface malerial of
diameter mm
Form 3 Figure 2, Armonng potential photographic siipplEmenT for assessing interniediale beds
(ie < dsp < 128 mm| lo be used in conjunction wifh Form 3 Checklist 1.
(Sheet 2 of 4}
RESULT FOR ALL STUDY REACHES
B-7
Form 3 Checklist 2: Grade Conlrol
A Grade conlrol is present with spacing <5Cl m or 2/3^ m
> Ho evidence of failure/inelfeclivenesa, e.g., no Jieadcullfng {>30 cm), no
aclive mass wasting (analyst cannot say grgde control sufficient if mass-
wasling checklist indicates presence of bank taiJure), no exposed bridge
pilings, no culverfs'structures undermined
• Hard points in sen/iceable condition al decadal trme scale, e.g., no apparent
undenii>ning, flanking, failing grout
- If geologic grade conlrof, rock should be resislanl igneous and/or
metamorphic; For sedimentaiy/hardpan to be classified as 'grade control', it
should be ot demonstrable strenglh as indicaled by field testing such as
hammer lest/borings and/or inspected by appropriate stakeholder
B intemiediate lo A and C - artificial or geologic grade control preseni bui
spaced 2/Sv m lo 4VSv m or poientiai evidence ot failure or handpan of
uncertain resistance
Grade control absent, spaced
of ineffectiveness
'100 m or >4/Sv m, or dear evidence
Form 3 Figures. Grade-control Icondifion) photographic supplement for assessing intermediate
beds (1G<d5i)<12e mm) to be used in conjunction with Form 3 Checklist 2.
/S^reef3of4^
RESULT FOR ALL STUDY REACHES
B-S
Regionally-Calibrated Screening Index Threshold for Incising/Braiding
For transitional bed channels (dso between 16 and 128 mm) or labile beds (channel not incised
past critical bank height), use Form 3 Figure 3 to determine Screening Index Score and complete
Form 3 Table 1.
Graphed results
apply to Reaches
E5, E6, and E7.
0.001
0.1
stable
10% risk
^ dso (mf")
X Braided
50% risk
11 mm 100
+ Incising
90% risk
c o
<»
S s
128
96
_S<L
0.145
0.125
Q.114
64 0.101
GIS-derived: , " v, . r.^-. -i:;;;
Field-derived: • (1 00-pebble count)
O)
o
48
32
16
8
4
2
1
0.5
0.087
0.070
0.049
0.031
0.026
0.022
0,0li8
0.015
64mm for dense
vegetation in
Reaches E1-E4,
E8, and W1-W4
Form 3 Figure 4. Probability of incising/braiding based on logistic regression of Screening Index
and dso to be used in conjunction with Form 3 Table 1.
Form 3 Table 1. Values for Screening Index Threshold (probability of incising/braiding) to be used
in conjunction with Form 3 Figure 4 (above) to complete Form 3 Overall Vertical Rating for
Intermediate/Transitional Bed (below).. Screening Index Score: A = <5p% probability of incision
for current Qio, valley slope, and dso; B = Hardpan/dso indeterminate; and C = >5d% probability of
incising/braiding for current QM, valley slope, and dso.
dso (mm)
From Form 2
e *ri 0 5 /mi-5,_o,5. S»*Qio'''' (m'' %"•*) &vUio im IS ) 50% risk of incising/braiding
From Form 1 ^^^^ ^^^^^^ p^^^ 3 ^^^^^^ 3 g^^^g
Screening Index Score
(A, B, C)
Overall Vertical Rating for Intermediate/Transitional Bed
Calculate the overall Vertical Rating for Transitional Bed channels using the formula below.
Numeric values for responses to Form 3 Checklists and Table 1 as follows: A = 3, B = 6, C = 9.
Vertical Rating = j{(-,Jarmoring * grade control) * screening index score}
6X3 X 3 = 3,6
Vertical Susceptibility based on Vertical Rating: <4.5 = LOW; 4.5 to 7 = MEDIUM; and >7 = HIGH.
CS/7eef4of4;
RESULT FOR ALL STUDY REACHES
B-9
FORM 4: LATERAL SUSCEPTIBILTY FIELD SHEET
Circle appropriate nodes/pathway for proposed site
OR use sequence or questions provided In Form 5.
yes
at^iBtiriEnts (mating?
(Sheet 1 ofl)
RESULT FOR ALL STUDY REACHES
B - 10
FORM 6: PROBABILITY OF MASS WASTING BANK FAILURE
If mass wasting is not cunrentiy extensive and the banks are moderately- to well-consolidated, measure
bank height and angle at several locations (i.e., at least three locations that capture the range of
conditions present in the study reach) to estimate representative values for the reach. Use Form 6 Figure
1 below to detemiine if risk of bank failure is >10% and complete Fomi 6 Table 1. Support your results
with photographs that include a protractor/rod/tape/person for scale.
Bank Angle
(degrees)
Cfrom Field)
Bank Height
(m)
(from Field)
Corresponding Bank Height for
10% Risk of Mass Wasting (m)
(fmm Fonn 6 Figure 1 below)
Bank Faiiure Risk
(<^(y^ Risk)
(>10% Risk)
Left Bank -— 2 m — <10%
Right Bank — 2 m <10%
probcfbiHty ot rnciss wcisFing rsp^SSaill.
in moderateiy/well consolidated banks ^'^^^-^'^^^^
O Stable-- 10%Risk—50%Risk ™-90%Risk X Unstable
^ io 00 0
I 1 i 9? Ch ^
Bank height and angte
schematic
Form 6 Figure 1. Probability Mass Wasting diagram. Bank Angle:Height/% Risk table, and
Band HeightAngle schematic.
(Sheet 1 of 1)
RESULT FOR ALL STUDY REACHES
B-12
ll now 5an Diego BMP Sizing Calculator
R»utl VlBw
f^. Define Drainage Basins
CRITICAL^STRESS CALCULATOR RESULTS FOB REACH El
^•-•.^•iw-' Agua Hedionda Wale rs hed
Details
Ranch Costera & El Carnino Real Widening
POC
Manage Your Point ot Compfiance fPOC)
AnaJyzeifie recemng waler al iny'Poini or Compiiance' by iiompleiirKj
Ehistorm Click Edit-UlQ eFiTiSthe appropnate fieUg Thencltklhe
L^ate [Hiflonro cfllculaleifie ciK\cni flow ami totf^-llaw Ihreshidil
corjWiork Finally clicli Havp locorrfliiilhe changes
Cancel I Sa^e m Updsf«
C tunnel SutcapUbiriif:
Low Flow IhmhoFd:
:L_._. Walirehvcl Araa (u}^ [034
Chan rat BottDBi Widtti {ftj: ^cTo
Channel KB Ighi irt). |9.a
Channak Slap«L
Vvrtiul SuKtptitillllY: LowLVtrUcal]
LaEerdl SUKceptltiililTr Law(LaTiral 13
UKnOW San Diego BMP Sizing Catculator Hcirnc Corilact^ Legal
Define Drainage Basins
CRITICAL STRESS CALCULATOR RESULTS FOR REACH E2
Fi^.i.i^ Agua Hedionda Watershed
MLip DfltallB
Pioitc! Ranch Costera 4 Ei Camino Real Widening
POC
Mffnage Your Potnt of Con^pHance (POC)
Analyze lite receiwng water at lhe 'Poinl of Compiiarice'By toirptermg
llus lorm. Click Edfl arx) erter BietftiprnJimatefielils, tlieii click flie
Updaie buHiinlocalculaEe the Clival Soft artd fow-ltcrt UiresJiold
condnron. Rnaty click Savelo commfl [he changes
Cancel • Save • Update
CtuFintI SuG»Fmblllry: ^^r~ _^ , 'j
Channel Aitntedi V#i
Wat«ntiid Ana ju): CI.Q721
MlWrlaL' |VvgptaliDn
CJunr>el Top Widlh (tfl: |/5.Q
CfHpnil Boimn Width IR): ^
Channal HalgtM (tt):
Vardcal SutcBpllblllty; LowCVtrdcal
LararaL Suicapllblllly; Low (Liltral]
Dlego 8MP Sizing Calailstcr Hrtni" Contacts LefriH
Jtap IKO^M 0[)e"
Map Dalalls
CRH-ICALSTRESS CALCUl^Vti^frR^^ FOR F^^^^^
Define Drainage Basins i^^'^jji Agua Hedionda Watershed Prju-ci Ranch Costera & El Camino Real Wjdening
POC
Manage Vour Point of Comp^anr^e (POC)
Analyse the recenflng waler a( [lie'Poinl Ql Compliarn:e' by compHirig
litis fomi C6cii Ecii aJid enler the appropnale fields, ilien clicli Hie
Updaie tualon lo caitiJaieilie cntrcaffc^ arid lowflow Ihie-diuld
condition Finally, clickSavcto commitrtiechan^s
Cancel I Save • UpE^^te
Channal ^uKBpHUIIty
Low now Ti™^^:
GtiannM AaMt»d; YES
VMHTStwd ATH (K): }0.0732
Maurlat VvgelatlDr
RDughnaii: JO'lDD
ChJnnel Top WiillTi jftV 43.0
Ctunrwl Bmom Width (ri): E.D
ChapnalHetghtfrt): [iO.O
Cnannal Slope; 1D.03B3\
Vanlr^l Sutctpdbll^ Low [Vanlcal)
LatiraL SuHeptlNlltr LowlLalenl}
: VL
3
uKnow Sa n Oiego BMP Sizing Calculator
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Map DetailB
CRITICAL STRESS CALCULATOR RESULTS FOR REACH E4
^ Define Drarnage Basins it^^m Agua Hedionda Watershed pr.^ir,!;' Ranch Costera & El Camino Rea! Widening
POC
Manage Your Point of Comi^lance (POC)
^al/zeLbe recer/in^ wal^ ^Uie 'Pojrri uf CuFiipliance'bv compkeling
HdStalrn Click Ertfl and enter lhe appropnalEllelils, then elicit JTie
Updele butliHi to caiciii^ied^e crdicallViwand low-fkiwiTirtsrialir
condfljon FinaBy, clicI" Savi? lo iiJiTirjfUhi'changes
Channel SuHvpliblllly;
Low FIDW Thmh^d:
CancHj • 3ave • Update
Channal Amuiiad: Vei
Wjtarshed Area [ac}: C 1?73
Vaithjl SuufiFirJtiEtlty: Low |VartJcal)
Lataral SuicaptibLllfr: Low|Lal«ral} 1^
Ualarlar; iVagatation
ChaiHrtI Top Width lft} f^M.0
Channel BatTDm Width (fi): 20.0
Chann*r Haighl (fi): B.Q
Channel Slope. 0.0247
San Diego BMP Sizing Calculator -.wim llpme Cmilacis Legal
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Map Details
CRITICAL STRESS CALCULATOR RESULTS FOR REACH ES
^ Define Drainage Basins n.^^.r, AQUB Hedionda Watershed Prt^eci Ranch Costera & El Camino Real Widening
POC
Manage Your Point of Compliance (POC)
Analyse ihp receninq water al [hp 'Pmnl nr CompijaTice' by complehng
Uiisrorm Clicltbdil and enter Ihc appiapnatelieHs, Ihen cfck Itw
Update buKon to caEculare the cr tf icfll flow and low-flow ihr^-sbokJ
cflraMKHi Finally, cltck 5avik lo commrl lhe charfges
Can»l • SAtTB • UprlatB
Channel SuvcepHbllitY:
Low Fktw Ttfreihcrid:
Channel Aieeuvd; Yai
Waianhed Area lac); [0.3963
Maurlal: jVegeUtrDn
Channel Top Wdth |f1): ?90.D
Channal Bottom Widlti |tt}: 3fi.D
CtiannaJ Height jS.O
Channel SlopK [D.QOS^'
Veftlur 5ui»pfJi>inEy; LowfVartlcal
Lateral Suuftplitrillly; Lew (Laferal}
UKnOW 5dn Diega BMP Sizing Calculator i.v^.'Jj lOTfe Corilacl^ legal
r^ap Detallft
IVTeVf
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CRITICAL STRESS CALCULATOR RESULTS FOR REACH £6
-„ _• ,• V'
Define Drainage Basms fiasm Agua Hedionda Watershed i^i^oi^^cL Ranct) Costera S EL Cammo Real Widening
POC
Mariage Your Point of Compliance pOC)
Analyst lhe receriing waler arthe'Pmni ol GompBance'by cQmplding
ci'^ rumi Olich Editandenieriheappropraiefiekls, dienclicktfie
iJpdsFe iNiOon to naLcuEate the cmlcad How arul low-flow Ehleshukl
comEHicn Finally, clich Save lo coinmfl ihc ch^riyr'5
Cancel • Save • Upditls
Channel Susceptibility'
Low Row ThFSfthald 3^'
Channel Atwtied: Yes
ttater&hed Area {ac} a.A»4|
Malarial: Vegetation
Roughneu: ^^]00..-^ , _
Channel Top Width {ftj: Z70.0
Channel Bonrvii MVrdih (% l^.O
Channel Helabl (fl)r kfl
Channel Slop*' m.QOBS
3 Vertical SuicepilbllItT: LowfVcnlcal]
Lateral Susuptltilllly: Low(Lateral)
uKnow San Diego BMP Sizing Calculator Home Ciinf.id* Legaf
Hflpflaffl WH».iileil 1^ 0[.e:i'^iiiTm,i,nj
Map DetdUt
i.fmuhWew CRITICAL STRESS CALC^ _ _
^ Define Drainage Basins R^v,n Agita Hedionda watershed Pir^^rr Ranch Coslera & El Camino Real Widening
Manage Your Point of Compliance (POC)
fljialyze Ihe reiavmg waEer al Ihe 'Point o( Compliance' by comptenng
Ibe Irjnr. Clicli Erfu and eiaer ifie appnjpfiate Hedis, tiien ckk the
UpifalebuitaniQ caJeutate the cntical llQwandfo*-niiwlhresJiokl
condnion FpnaHy, rlmliSaifeln CMnmfllhcchFinges
Cancel H Save I Update
t^hamiel AssflHed: ft^
Water«hvd Area {ac}: [4.BUI
Material: jVegHlatlon
RouBhneii: Ifl.I^^ ,;
Channel Top Vifldth jtt}; |22D.O
Channel Bottom Widlh [ni: jaso
Channel Height (ft): {+•
Channel Slope: HLDOffOj
L.
Channal SutceptitilEltf:
Ltiw Fl»f ThruhoJd:
VtrTicjl SirueptlbllitT: Low (VvitfcaJ)
Lateral SbtcapUbllltr: Low ILateral}
uKnow San Diego BMP Sizing Calculator
HID dflia [ii[>viiie<i Dpenvir«cff,r[iii
Map Detalle
Result View CRITICAL STRESS CALCULATOR RESULTS FOR REACH E8
I ^ Define Drainage Basins B.^,.. Agua Hedionda Watershed sv^i.c Ranch Costera & El Camino Real Widening
POC
Marrage Your Point or Compliance (POC)
Analyze the receiving ^ala at the Poim ot Coftipliance' by completing
UiL'ilnnti Click EdaarMl enta lhe appiopnale I*ld5 ihen click Cie
Upddlp button ta calculalo UIE i:ntical How arkd ki^-ltaw llaeshaW
ccndFlKKL Finally, click SflvelocommPfhe chafes
Cancel • Save • Upd^ite
Ctiannal SincsptibMity:
Low Flow Threihold:
Ch«nnal Aeieiiad: Ya«
Waonhed Am [ac}: £.111^
MalBTiar: Vv[]vtiiion
Roughnaai. O.lDO
Channel Top Width (ft): jUW.O
Channel Bottom A^dih M.Q
GhaFinBlHelghtfftJ; \2.0
Channel Slope: [D.ODQI
V«rti»l SiiacepdbJIHyt U* IVerHcal)
Lateral Siucepilbllity: Lon {Lateral}
uKnow San Diego BMP Sizing Calculator (
HetuhVlew
Map DetaHa
CRITICAL STRESS CALCULATOR RESULTS FOR REACH W1
——,^
Define Drainage Basins H^-.m Agua Hedionda Watershed Project Ranch Costera & El Camino Rea^ Widening ^
POC
Manage Your Point ot CompJIance (POC)
Analyze lt» [pceivins waler at Ihe 'Point uf Camp*ancp' by completing
[his lorm Click EdB and cnler lhe appropftate Itekl-i, Ihen click die
Updaie huHon to calcutale the critical flow and tow fti* tiireshold
condiliQFi Finally, cfitk Save In cDmmH Cie changes
Cancel Updat?
Channel AtH^sad: Yen
Watarmhed Area {ac}: D.OQU
Material- [Vvgataticn
Roughness ^100.
Channal TopWIdih [ft): SD.Q
Channel BoUota WhJIh (ft): S.Q
Channel HeJghllfl]: 4.0
Channel Slope: 0.044S
"-••WIS
Channel Susceptibility
Low FJ«w T^kreihold
Venical Sifueptlbflitr LDh(VBrtlcal|
Lateral SuieepiiNlity; Low (LtenI}
uKnow San Diego BMP 5i3ing Calculator
rjB[h cUiEa pr™»'idi=a Of'i^n ^rn- u u ^
Mao Detail•
ir^eniKVIfev
Define Drainage Basins
CRITICAL STRESS CALCULATOR RESULTS FOR REACH W2 " '
^-a-.:-! Agua Hedionda Watershed Praieci Ranch Coslera & Ei Camino Reat Widening
POC
Manage Your Point of Comptiance (POC)
'V>3lyzclhc fecKn/ing vjaler alliie 'Pomlot Compliance' by completing
Ihs form Clitl; and enter Ihe appn^idl--fiekls. ti«n clich Ihs
Updaie bullaii IQ cslciilalelhe cnLcaJftiw Finil k-w-flow ihreGhold
cofidnion Finally, clicli Save to commil lhe changes
Caticrri • Save • Update
Channel Sutcepilbil iiy: [LOW ., .:,
Low Flow Threshold:
Channel Aaieaeetf: Yea
Watershed Araa (ac): 101076
MatatialL | Vegetation
RoughncBV |0,t00 • 1^
Channel Top Width (ft): \2QU.0
Ctannel BoETom nndth (fl): 2D.Q
Channel Height |R}, ko
Channel Stope: 0.0191
VartJcal SutcBpLlbllity: Low|VBrtlur]
Lai^ SuKeptib^lltr: Low {Lateral)
••I. I.eq^
Result view CRITICAL STRESS CALCULATOR RESULTS FOR REACH W3
M^P Detalls
Define Drainage Basins F:,if.ij' Agua Hedionda Watershed Pii^M I Ranch Coslera & El Camino Reai Widening
POC
Uanagn Your Pornl of Compllartce (PDC)
Analyze lhe reteivwig wafer at the 'Point of Cornpiiance' by complefiig
tins fonn Click Edit and enter the appropnate lipfes, llipn etch fhe
Updaie bullonto caEciiEalethecniicat Now and !ow-lk>LV Ihreslvld
rondtfion Rnalt^, clfcli Save to commit lhe changes
Cantol • Save • Update
Channel Ateeued: |Yae
Watershed Aru (ac): 1.11^7
Material
Roughness:
Channel top Width |ff].
Channal BoTtom VAdlh jtt]:
Chann*I Haighl (ft):
Channel Slope:
Vagetailon
BO.0
ZD
0.0127
Channel SuBcaptlblilty: ^
Low Row Thtpshoid
VerUcal SuKepHbiniy: |LDw{V*iticjl)
Ulera] S^iiuptibility: | Low {Lj»nJ}
•3
LarJjlViflw
uKnow San Diego BMP Sizing Calculator l!cme Coriiiicrs Lefji
Rabun Vl«w CRITICAL STRESS CALCULATOR RESULTS FOR REACH W4
Map Details
Define Drainage Basins l!H--.;n Agua Hedionda Watershed Proi.jiM Ranch Coslera & El Camino Real Widening :
POC
Manage Your Point of Compliance (POC)
Arimvie tne receivifig wafer m ine 'Poim al Compliance' by cnmplettng
IJiclifm-- ClK-k Edit HUfleplH" thFappropfHtClieTll'i, thPI cfccfc thU
Updaie tnHlonlo cak^ulalelhe cnhcal flow andlQW-nowDireshohl
condilicn Tmally, cliikSa^ to tommit the changes
Cancef | Save • Update
Channel SuicepiiblllTy: ^Off ^
LowFlow Threshold:
Chanrrel Aitaued: Yet
Watershed Area (K|: 1.2eSB
Material: Vegetailun
Rotighneii: ]0
Channel Top Width {ft): TO O
Channel Bonom Width (ftl: jtfiO
Channel Height (Tt): |i.T~
Channal Slope: DQia^
Vertcal SuKeptibLlliy: |LDW (Venical)
lateral Sutcepflblllty: |Low (Laieral)
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