HomeMy WebLinkAboutCT 00-02; CALAVERA HILLS PHASE 2; SUPPLEMENTAL IMPACTS AND MITIGATION ASSESSMENT REPORT; 2003-10-27C—'I CICI(J
LAND USE / COASTAL PLANNING PLANNING LANDSCAPE ARCHITECTURE • ioo SYSTEMS ____ POLICY AND PROCESSING
ENVIRONMENTAL MITIGATION
October 27, 2003
Mr. David Hauser
Deputy City Engineer
CITY OF CARLSBAD
1635 Faraday Ave.
Carlsbad, CA 92008
Mr. Don Mitchell
Vice President
McMILLIN COMPANIES
2727 Hoover Ave.
National City, CA 91950
RE: Supplemental Impacts and Mitigation Assessment Report.
Calavera Hills/Bridge & Thoroughfare District No. 2/Detention Basins
Extension of Rip Rap within Calavera Creek
Dear Mr. Hauser and Mr. Mitchell:
Planning Systems has conducted an analysis of the impacts associated with the exten
s
i
o
n
o
f
a
70-foot length of rip rap protection along Calavera Creek as requested by the proj
e
c
t
hydrologist. This report provides a description of the project and our findings regardi
n
g
biological impacts and mitigation.
1.0 Introduction
Wetlands permits were issued in 2002 for the Calavera Hills/Bridge & Thorough
f
a
r
e
District No. 2/Detention Basin project in Carlsbad. These permits included;
Department of the Army Section 404 Permit No. 200100215-RLK, dated 5/15/02 Department of Fish & Carrie Streambed Alteration Agreement Section 1601 #R5-
2001-00074, dated 6/3/02, and
Regional Water Quality Control Board Order No. R98-2002-0014, dated 2/13/02.
A minor modification to these permits is now being requested. This modification
involves the extension of a 70-foot length of rip-rap protection to Calavera Creek. Thi
s
extension of rip-rap has been determined to be necessary by the hydrologic engine
e
r
,
i
n
order to provide creekside stability at the downstream end of the approved Detentio
n
Basin BIB outlet.
Agency Permit Amendment Assessment
1 Rip Rap Extension
.10/23/03
1530 FARADAY AVENUE. SUITE 100 • CARLSBAD, CA 92008. (760) 931-0780 • FAX (760) 931-5744 • ptanningsystems@nctimes.net
This report is intended to analyze the wetlands impacts that.are associated with the
referenced minor modification, and to provide a supplement to the adopted
restoration/ monitoring plan titled Final Habitat Restoration and Monitoring Plan f
o
r
t
h
e
City of Carlsbad Bridge & Thoroughfare District No. 4, The Calavera Hills Project, and
the Detention Basins Project In Carlsbad, California, prepared by RECON, January 21,
2002. This plan will analyze and quantify impacts associated with the proposed design
modification, and will reiterate material and concepts from the adopted RECON pla
n
,
maintaining in-kind mitigation ratios and habitat-types to be created. To reduce impacts to a level of insignificance, it is proposed that new habitat be created, and located
-next to the approved College Boulevard / Cannon Road. wetland restoration site, situated in the
Robertson Ranch "panhandle", northerly of Detention Basin BIB. The vegetation
community of the proposed mitigation site is identified in the project FEIR as
"agriculture". The proposed mitigation site is located immediately adjacent to existin
g
wetland habitat. It is proposed that Maintenance and Monitoring requirements of the
adopted RECON plan are implemented in this expansion area without. change, so tha
t
redundancy and confusion is avoided.
2.0 Rip Rap Extension Description
The originally permitted plan for discharge of storm water into Calaveras Creek called
for both new concrete drainage structures and the placement of 1/4 ton rip rap on the Calavera Creek embankment. Additional hydrologic study indicates that the permitted
plan provides inadequate erosion protection for the existing concrete lined embankm
e
n
t
and adjacent portions of the Rancho Carlsbad Mobile Home Park in the occurrence of a
large flow event. Approximately 180 sq. ft. 1/4 ton of rip rap was permitted within thi
s
area immediately downstream of the Detention Basin BJB outlet weir in conjunction
with the original permitting. However, the project hydrologic engineer has determined
that to adequately protect the channel in place would require the placement of an
additional 70-foot long section (0.07-acre area) of riprap along the channel, and thus, this
additional rip rap section is proposed.
3.0 Rip Rap Extension Impacts
Open water flood channel/streambeds such as Calavera Creek support both aquatic
vegetation and intermittently, the wetland vegetation that can inhabit sites prone to
seasonal scouring. Animal species dependent on riparian ecosystems also utilize open
waters. State and federal resource agencies regulate impacts to open water habitat
a
n
d
the wetland communities sustained by it.
Ornamental vegetation (0.02 acre) will be impacted by the revised rip rap placement,
b
u
t
this plant community is not considered sensitive plant communities by local, state, and
federal resource agencies. Riprap will also be placed on previously developed, con
c
r
e
t
e
-
lined portions of the channel (0.03 acre). No mitigation is proposed for impacts.to non-sensitive plant communities or for previously developed areas.
Agency Permit Amendment Assessment
. 2 Rip Rap Extension
10/23/03
PLANNING
SYSTEMS •
Habitat types to be impacted due to additional rip rap placement in the existing cha
n
n
e
l
were identified by field mapping of existing biological resources utilizing a 40 scale engineered base map (Figure 3). This analysis resulted in the determination that
permanent impacts to 0.02 acre of ornamental vegetation and 0.03 acre of existi
n
g
concrete embankment (developed) will occur. A temporary impact to 0.02-acre op
e
n
water will also occur as a result increased placement of riprap along the existing
embankment. The 0.02-acre of 'open water habitat impact is considered temporary
because the riprap will be placed at a low enough elevation to allow the strea
m
b
e
d
t
o
b
e
returned to its pre-construction elevation. Stockpiled streambed sediment will be p
l
a
c
e
d
over the installed riprap, so that the post-construction channel bottom will b
e
r
e
t
u
r
n
e
d
to the pre-construction surface material.
.
Table 1: Rip Rap Extension Project Impacts
Habitat. . Impacts Mitigation
Ratio
Required. On-site
Mitigation (acres)
Open Water 0.02 (temporary) 1: 0.02 Ornamental 0.02
. NA NA Developed 0.03 NA NA TOTAL 0.07 0.02
4.0 Rip Rap Extension Mitigation
To mitigate for the additional rip rap installation impacts, it is proposed that 0.
0
2
a
c
r
e
o
f
Southern willow scrub (SWS) habitat is newly created immediately adjacent to the
previously approved mitigation site located north of Detention Basin BJB, in the
Robertson Ranch panhandle (Figure 3). The creation of SWS habitat is consistent wi
t
h
the originally approved plan, providing an expansion of local Least Bell's vireo
h
a
b
i
t
a
t
.
Thus a net 0.02-acre increase in the area of wetland revegetation is proposed
immediately adjacent to existing wetland habitat on an area presently occupied by
domestic agricultural operations.
4.1 Implementation
Mitigation for biological impacts resulting from the Rip Rap Extension project will total
0.02 total acres of restored Southern Willow Scrub vegetation.
Table 2: Summary of Mitigation Required
Rip Rap Extension Project
. 0.02 ac. TOTAL 0.02 ac.
Agency Permit Amendment Assessment
Rip Rap Extension
10/23/03
PLANNING.
SYSTEMS 1:301
The mitigation creation site will be prepared and as described in the approved plan
,
t
o
an elevation no higher than adjacent mitigation site grading. Supplemental irri
g
a
t
i
o
n
will be utilized to assist establishing plantings, and discontinued on a timetable as
stipulated by existing permits. Plantings will be from both one-gallon container
a
n
d
seed, at the same rates, and per the specifications identified in the approved Recon Pla
n
,
as follows:
Table 3 - Riparian Scrub Planting Densities
Species # per
acre
.# per 0.12
ac.
size
Mulefat (Baccharis salicfolia) 200 24 1 gal Arroyo willow (Salix lasiolepis). 100 12 1 gal Black willow (Salix goodingii) 100 12 1 gal Red willow (Salix laevigata) 100 1 12 1 gal Western sycamore (Platanus racemosa) 75 9 1 gal Blue elderberry (Sambucus inexicana) 50 6 1 gal California rose (Rosa calfornica) 50 6 1 gal Fremont cottonwood (Populusfremontii) 25 3 1 gal
Table 4 - Riparian and Transitional area Seed Mixes
Species # per acre %pur/%germ Riparian seed mix
Arroyo willow (Salix lasiolepis) 2 N/A Mugwort (Artemesia douglassiana) 1 10/50 Mulefat (Baccharis salicifolia) 3 2/20 Western ragweed (Ambrosia psilostachya) 2 85/25 Tarragon (Artemesia dracunculus) 1 10/50 Transitional Area and Slope Mix
Blue elderberry (Sambucus mexicana) 2 95/20 California buckwheat (Eriogonumfasciculatum) 3 10/65 California sagebrush (Arteinesia calfornica) 2 15/50 Purple needlegrass (Nassella pulchra) 3 70/60 Giant ryegrass (Leymus conclensatus) 0.25 70/80
Signage will be placed at the edge of wetland areas as stipulated in the approved pla
n
.
The work proposed in this plan will be included in the as-built report to be prep
a
r
e
d
f
o
r
the City of Carlsbad, the CDFG, and the USACE, as conditioned by the existing p
e
r
m
i
t
s
.
Agency Permit Amendment Assessment IR Rip Rap Extension
10123103
PLANNING
SYSTEMS i[
5.0 Maintenance, Monitoring, Reporting, & Completion of Mitigation
All maintenance and monitoring activities shall be performed as stipulated by th
e
existing permits and by the approved RECON plan. Maintenance and monitoring of
mitigation areas proposed in this plan shall be seamlessly included with the
-work required for the original restoration area of the project.. Reporting of monitoring. results
shall occur per the approved schedule as stated in the RECON plan. Performanc
e
standards as stipulated in applicable permits and per the RECON plan shall be
employed to determii-ie if the habitat creation has successfully established. Remedial.
measures shall be employed if performance standards are not achieved by the en
d
o
f
t
h
e
fifth year. At the end of the firth year, a final report will address the status of this
additional mitigation as apart of the overall success of project required mitigation.
Upon resource agency confirmation of project establishment success, the owner/pr
o
j
e
c
t
proponent will be released of all obligations.
' ..
Agency Permit Amendment Assessment
Rip Rap Extension
10123103
PLANNING
ijj
-. ""u bros. Map No. 1107, 2003
0 950 1900
NORTH SCALE
Figure 1
Vicinity Map
Cannon Road Reach
Carlsbad, California
LEGEND
PROPOSED IMPACTS
MITIGATION AREA
DETENTION BASIN BJB
CANNON ROAD REACH 3
3 PAM G3
(TO) o1 raz (Tao) 2-7
PS NO. 991146 10/28/03
Figure 2
Location Map
Cannon Road Reach 3
Carlsbad, California
0 350 700 FT
NORTH 1 700
PS NO. 951145 10t28/03
-
, :-
,
Approved -box culvert béneth I •(J future Cannon Rood
ell
Headwall
Colavera Creek outfolls, onto Arizona crossing
(AI
--3
'\ New Concrete Weir
, -channelizes creek flow to proposed rip rap bed
7
Proposed Impact _Area
Existing Wall 17
RIP RAP IMPACTS SUMMARY
LEGEND mitigation
. ' -'
habitat type acres ratio req d
PERVIOUSLY PERMITTED IMPACTS OPEN WATER (temporary)- 0.02 1:1 . 0.02, USACE 404 No. 200100215—RLK ORNAMENTAL LANDSCAPE 0.02 no no CDFG
•
1601 No. R5-2002-00074 DEVELOPED 0.04 no no cx:;cF) AREA OF RIP RAP PLACEMENT (Concrete at fin, grade)
. . •
.' TOTAL ADDITIONAL IMPACTS 0.08* 1 0 15 30 FY
Figure 3
-• NORTH SCAtE . .
- Rip Rap Field in Calavera Creek Impacts ,_ F Cannon Road Reach 3 . raflDAy awn. Wflz a Cs a * Carlsbad, California
03 ' 1
--. -. - -----.--
,----- -...
..(.
\ •;r1
:-W
I'
-
c_,, -•,j-'1 '-ei"• r
___
t air__Lt i, ;
Agency Permit Amendment Assessment
Rip Rap Extension
10/23/03
PLANNING
SYSTEMS i.I
10
6.0 References
Bossard, C.C.,Randall, J.M., and Hoshovsky, M.C., Editors, 2000, I
n
v
a
s
i
v
e
P
l
a
n
t
s
o
f
California Wildiands. University of California Press, Santa Rosa,
C
A
.
3
6
0
p
p
.
Dale, N., 1986, Flowering Plants of the Santa Monica Mountains, Ca
p
r
a
P
r
e
s
s
,
S
a
n
t
a
Barbara, CA. PP. 236.
Faber, P.M., and Holland, R.F., 988, Common Riparian Plants of Calif
o
r
n
i
a
.
P
i
c
k
l
e
w
e
e
d
Press, Mill Valley, CA. pp. 140.
Hickman, J.C., Editor, 1993, The Jepson Manual, Higher Plants of Cali
f
o
r
n
i
a
:
U
n
i
v
e
r
s
i
t
y
of California, Berkeley, CA, pp. 1392.
Holland, R.F., 1986, Preliminary Description of the Terrestrial Natural
C
o
m
m
u
n
i
t
i
e
s
o
f
California, Unpublished technical report. State of California, The Res
o
u
r
c
e
s
A
g
e
n
c
y
,
.
Department of Fish and Game, Natural History Division, Sacram
e
n
t
o
,
C
A
.
O'Day Consultants, July 31, 2002, Carlsbad Tract No. CT 00-02 Grading
P
l
a
n
s
f
o
r
Cannon Road :
RECON, January 31, 2002, Final Habitat Restoration and Monitoring P
l
a
n
f
o
r
t
h
e
C
i
t
y
o
f
Carlsbad Bridge & Thoroughfare District No. 4, The Calavera Hills
P
r
o
j
e
c
t
,
a
n
d
t
h
e
Detention Basins Project in Carlsbad, California
1ECON, November 2001, Final Environmental Impact Report (Effi No.
9
8
-
0
2
)
(
S
C
H
N
o
.
99111082) Calavera Hills Master Plan Phase II, Bridge and Thoroughf
a
r
e
D
i
s
t
r
i
c
t
N
O
.
4
,
& Detention Basins
Reiser, Craig H., Rare Plants of San Diego County, Aquafir Press, Im
p
e
r
i
a
l
B
e
a
c
h
C
A
Sawyer, J.O. and Keeler-Woif, T.,1995, A Manual of California Veget
a
t
i
o
n
.
C
a
l
i
f
o
r
n
i
a
Native Plant Society, Sacramento, CA. pp. 471.
U.S. Department of Agriculture, Growers Weed Identification Handb
o
o
k
.
P
u
b
l
i
c
a
t
i
o
n
Number 4030, University of California, Oakland, CA.
Ill Lt1Q uvsIopmetit +619-3353150 1-785 P.02/04 F-274
RICK
ENGINEERING
-
. Cc)14PA.NY 714 - Rh,*rsidc, • ()raag rliocnix -
Water Rcurte!s DvLiiO'z
AUgST 2•17 2003
Mr. Don M.tcbe1l
McMifliri Companies
2727 HoOlver AVellUe
Noial City, California 91.950
SUBJECT: REVISIONS TO IUPRAP SIZThG FOR. CALAV1RA CREEK
(RICK 2NGThIiERiNG COMPANY JOB NUWR 13916)
Dcar Mr. Mjtchcll:
Rick Engineaxing Company has revicw;d previous au1y8es of the size and tents of slope protection (riprap) require4 withrn Calaver4 Crcck dwnstreani ottbc wcir.
In the previous 1exer dated July 10, 2003. the specified riprap pa6 consisted of V ton (Tlucicness 2.7 ft) riprap extending xtnm the weir Ibr at ]cast 2 10*t, or to the upstream ettd of the tirtg concrete-hued channeL, whichever is greater. Based on field surveys, the upstream and of the existing caricrctc-linc4 ehennel occurs 70-feet downstream of the wer
lhe design of the r!prap pad Irns been rcvise4 to provide s bifity at the downsneam end of the riprap, based on th shortened length. Tlic tbielness of the riprap at the downmcam end of the pd will be increrneutafly increased to 6-feet for a length of 194eet. This modiIcatqn cocs not provtdc additional energy disipatiOri as poternl.aUy erosive vclocit:ies continue downstream of the riprap pad. A schemauc of the t-Lprap dowrttreaxn detail is attached.
The elevation at the top of riprap along the aogthfrn alope shall be 1.3 feet above the water surface elevation due to the angled confluence of the outlet structum and the creek (0.3 feet) and 1-foot of freeboard The elevation of the top of riprap along the southern bmk is 58.3 fcc.. The elevation of the top of nprap along the northern bank is 5.0 feet. Elevations of the top of riprap are based on a pd length of 70 feeT A schematic of the riprap limits is attached.
Please feetft-cc to contact Roberta Cronqust at (619) 6SR-1454 should you have any questions.
Sine crety,
RICJ< ENGINEERING COMPANY
Dcrmis C. Bowling,.'. -
R.C-E- #32838. Exp. 06/06
Principal
DCB:KH:nd.007
ndoaures
No. 32838
cc; Mr. Kiith }Iansor — O'Day Cootdt.z (with enclosures)
SjiDicu Cifama 2II0-26 (9)21-Q7O7 LAX. (19)21.41$ Www.lik.I7517c7flp rn
LcIIIU iJwv,up,riwii 1185 P.03/04 F274 1 RICK 4TN- NGINEJRING COMPANY P-4s I,ifl LL DAgo. • J N,: J3LL.
j
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- ..
... --H - ... .. --.
'11
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Liti ryi-1 I N L1IIU vblQpffl8 +193353150 TT05 P.04/04 F274
- -
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(
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FT-DM. Fs Enginearms Companu FX NO. E19 291 415 Jul. 11 203 2:PM Pt
RICK
N)Y ENGLEEIUING
11LfL COMP-NY
vc
'ter. RsouILes Division
July 10, 2003
Mr. Don Mitchell
McMillin Companies
2727 Hoover Avu
7Natiori4 City, California 91950
SUBJECT: VELOCITIES AT BIB OX CU1.VBT OUTLET AND RtPRAP SIZING FOR CALVE-.A CREBK (RICK ENGINEERING COMPANflOB NUMBER 13918)
Dear W. Mitchell.
.jek Eugheering Compaxy has performed analyses o determine the velocit
y
of flow discharging from the 5JB reinfored box culver (J&CB) outlet, aid the valocity of flow over t1e weir locae4 4ro±natly 60 feet downstream of the culvert outlet, The of slope protection (riprap) within Calavera Creek downstre= of the weir were also determined.
The weir eometry spccified for this analysis consists of a v-notch weir with 1:1 side slopes (horizont.alwertjca), a bottom elevation of 52.1 feet, and a top elevation of 59.4 feet, At elevation 59.4 feet, the welt extends on both sides of the 'v" horizontally for 9.7 feet, at which point the weir vertically increases in elevaricrn to 64.1 feet, A scbomttic of the weir is atcached. When plans for the weir have been fln41ied plasc scud a copy to Ricic 4igineering Company for rzview.
The hydrac calculations ptrformed for the above-mentioned gcomtrie 4etaij resu,lted in a velocity of 16.5 feet per second (fps) trough the RCB outlet aid 0-5 fps over the weir. Slope protection calculations were performed for Calavera Creek downstream of the weir. The required riprap size is V4 ton (Thic1iess = 2.7 ) and extends from the weir for at least Ii 0-feet, or to the davatstraam end of the existing conrete-1ined
c
b
a
n
n
e
1
,
whichever is greater. These locations should be field verified prior to installation. The elevation at the top of riprap along the southern slope shall be 1.3 feet above the water S14rface elevation due to the angled confluence of the outlet structure vU the creek. The elevation
of the wp of riprap tt the upstream end is 58..3 Leer and at the downstream end the elevation is .58.2 feet. The elevation of the top of riprap along the northern bani< is 58.0 feet on. the upstream end and 57,9 feet op the downstream end. ETvatons of the top of riprap are based oa a pad length of 110 feet. A. schematic of the riprap limits i& atracted.
5620Fnaikoa4 . Snitivo Calbmiu 92tL(,-259C (9)29-0707 fX. ( 9) .}-4tS
FROM Rck Enginear in,3 Cmar
-.
uiUIU T-44 P.02/04 P128 FPc NO. 1 61E 291 41b5
Mr. Don Mi'hdU
July 10 2003
Pag2
Additionally, the cnc:e in the channel mttbe removed prior to riprap installation, and a cocretc cutoff wall the sane thickness as the iitirap shaLl be construcied at the wpsreairi limit of the rpap-
Ficase fect fcee to conc Roberta Cranqust after July 15, 2003 directly at (619) 688-1454 should you have any qi.iesroas. For immediate assistance, Kathy hacker can be nad at (61) 90.:534.
Sincerely,
RICK EN3I14ER1NG COMPANY
Dennis C. Bowling, U.S. R.C.E. #32838, Exp. 06/06 Principal
1DCB:KH:rul.00
Enc'osures
cc: Mr. Keith Tiansoa O'E)ay Cosi4tants (with encosw-e)
U'-
1 -446 I'.U3104 -82 JL,±J, -IM -j 4.4tJfl( r r rLMI r Lr i i r c i LLi;IiC4 I r nt' rji.i. • cj. , zzq. i:,_, 4 1 RICK 4JIN) ENCNEERJNG SQ I'tol $ Callfrmft 2110.25%.a1tfj L358
_________________ LAND USE/ COASTAL PLANNING
PLANNING 'LANDSCAPE ARCHITECTURE LA3900
SYSTEMS
I ENVIRONMENTAL MITIGATION
____________________________ I POLICY AND PROCESSING
Addendum 1
Habitat Restoration and Monitoring Plan
For the City of Carlsbad Bridge & Thoroughfare District No. 4, The Calavera Hills
Project, and the Detention Basins Project in Carlsbad, California
1.9 Introduction -• ,•
The' Cityóf Carlsbad Bridge& Thoroughfare District No. 4, The Calavera Hills Project; and
the Detention Basins Project in Carlsbad, California is a fully permitted project. This
addendum to Final Restoration and Monitoring Plan For The .City of Carlsbad Bridge &t Thoroughfare District No. 4, The Calavera Hills Project, and the Detention Basins Project in
Carlsbad, California, Recon, April 3, 2002, is provided. to describe measures associated with
necessary Cannon Road Reach 3 realignment. Vegetation exists in the area proposed for
additional impacts subject to California Department of 'Fish and Game (CDFG) regulation.
These impacts have 'been fully described to CDFG in Supplemental Impacts and Mitigation
Assessment Report, Calavera Hills/Bridge & Thoroughfare District No. 2/Detention Basins
Amended Permit Request, Planning Systems April 2, 2004. This addendum is provided to
fully describe habitat creation measures proposed to mitigate additional project related
impacts to a level in insignificance.
2.0' Impacts and Mitigation Measures
Proposed mitigation measures are guided by CDFG Streambed Alteration Agreement
Section 1601 #R5-2001-00074, dated 6/3/02, Condition 4, stating "Any impacts generated
beyond those described within this. agreement shall be mitigated in-kind at a 5:1 ratio".
Therefore, proposed Impacts to 0.04 acre of Cismontane Alkali Salt Marsh will be mitigated
for at a 5:1 ratio by creation of 0.20 acre of CSM at Desiltation Basin BJB, a project approved
mitigation site situated along Calavera Creek (Figure 1).
Impacts to 0.03 acre of. Eucalyptus Woodland are also proposed. Eucalyptus Woodland is
not a habitat considered sensitive by CDFG and other resource agencies, so mitigation
measures are not typically proposed to reduce project related impacts to a level of
insignificance. However, in acknowledgement that raptors utilize tall trees including
Eucalyptus trees for perching, the project proposes the mitigation of impacts to 0.03 acre of
Eucalyptus Woodland by creation of 0.03 acre of Southern Willow Woodland in Basin BIB.
1530 FARADAY AVENUE • SUITE 100 • CARLSBAD, CA 92008 • (760)931-0780. FAX (760) 931-5744 planningsystems@nctimes.net
Table 1- Proposed Project Impacts and Mitigation Measures
Proposed Project Habitat Project Impacts Mitigatio Proposed
(acres) n Ratio Habitat
Creation
(acres! type) Roadway expansion Cismontane 0.04 5:1 0.20 /CSM
alkali marsh +14 spiny
rush*
Roadway expansion Eucalyptus. 0.03 NA 0.03 ! SWS
Woodland
Roadway expansion Agricultural 0.03 NA none
Land
* 14 Juncus acutis spp. Leopoldil, (Southwestern Spiny rush) are proposed
for transplanting from the area to be impacted to the CSM mitigation site.
Basin BJB has been designed larger than the approved mitigation requirement f
o
r
c
r
e
a
t
e
d
habitat. The proposed additional 0.23 acre of habitat creation can occur within
t
h
e
approved basin plan, and in an area not considered a desiltation basin (Figure
2
)
.
3.0 Rationale for Expecting Implementation Success
To establish wetland vegetation two conditions are necessary, adequate hydrolo
g
y
a
n
d
suitable soils. Provided that these conditions are available, wetland vegetation
c
a
n
p
e
r
s
i
s
t
.
Desiltation Basin BIB is the approved mitigation site for Phase I of the Cannon
Road/Calavera Hills project. It is located on the alluvial floodplain of Calavera
C
r
e
e
k
,
a
n
intermittent blue line stream that is the permanent hydrologic source for the mit
i
g
a
t
i
o
n
site. According to the project Final Environmental Impact Report, EIR No. 98-
0
2
,
R
e
c
o
n
,
November 2001, existing habitat types supported by Calavera Creek in the vi
c
i
n
i
t
y
o
f
B
a
s
i
n
BIB include Riparian Woodland and Riparian Scrub.
This floodplain was evaluated in terms of a wetland creation site and found b
y
R
e
c
o
n
t
o
b
e
suitable for project wetland creation, provided that the site was lowered to
b
e
t
t
e
r
a
c
c
e
s
s
subterranean hydrology. In this report (p. 10), the target hydrological regime i
s
d
e
s
c
r
i
b
e
d
by Recon as follows,"Agricultural development on both sides of Calavera' Cre
e
k
h
a
v
e
narrowed and confined the creek and vegetation to a narrow strip. The miti
g
a
t
i
o
n
a
r
e
a
adjacent to the channel will be excavated and widened. Vegetation in the creek c
h
a
n
n
e
l
currently receives surface runoff and water flow from Lake Calaveras through C
a
l
a
v
e
r
a
Creek. This channel will likely receive additional runoff as local development o
c
c
u
r
s
.
I
n
addition to surface flow, groundwater, located within 10 feet of the surface, will fa
c
i
l
i
t
a
t
e
revegetation."
Regarding agricultural use areas, it was observed by Recon in this document (p.6), that, "In
many areas subsurface flows support disjunct patches of hydroph
y
t
i
c
v
e
g
e
t
a
t
i
o
n
"
.
Further, in 2003 prior to Basin BIB grading, hydrophytic vegetation including Distichlis spicata, Salt-grass (FACW), Baccharis salicifolius, Mulefat (FACW-), and Malvella leprosa, Alkali-mallow, (FAC*), were observed re-colonizing actively cultivated areas now a part
o
f
Basin BJB (pers. obs. of author). Clearly, if appropriately accessed,
e
x
i
s
t
i
n
g
h
y
d
r
o
l
o
g
y
o
n
-
site will support additional wetland vegetation. Basin BJB is pro
p
o
s
e
d
t
o
b
e
g
r
a
d
e
d
t
o
a
n
elevation of between approximately two to eleven feet below th
e
e
x
i
s
t
i
n
g
s
u
r
f
a
c
e
e
l
e
v
a
t
i
o
n
.
According to Soil Survey San Diego Area California, U.S. Depart
m
e
n
t
o
f
A
g
r
i
c
u
l
t
u
r
e
,
t
h
e
soil type of Basin BIB is Salinas Clay Loam, 0 to 2 percent slope
s
,
(
S
b
A
)
.
T
h
e
S
a
l
i
n
a
s
s
e
r
i
e
s
consists of well drained and moderately well drained clay bar
n
s
t
h
a
t
f
o
r
m
e
d
i
n
s
e
d
i
m
e
n
t
s
washed from Diablo, Lirine, Las Flores, Huerhuero, and Olivenhai
n
s
o
i
l
s
.
T
h
e
s
e
s
o
i
l
s
a
r
e
on flood plains, and alluvial fans. This soil (SbA), is in small drain
a
g
e
w
a
y
s
o
r
i
n
t
h
e
c
e
n
t
e
r
of relatively large valleys. The surface layer is neutral and mildly
a
l
k
a
l
i
n
e
c
l
a
y
l
o
a
m
.
T
h
e
next layers are mildly alkaline and moderately alkaline. The su
b
s
t
r
a
t
u
m
i
s
m
o
d
e
r
a
t
e
l
y
alkaline. The rooting depth is 60 or more inches. Fertility is hig
h
,
d
r
a
i
n
a
g
e
i
s
g
o
o
d
,
a
n
d
permeability is moderately slow.
The habitats to be created in Basin BIB are Freshwater Marsh (FM), Southern Willow Scrub (SWS), and Cismontane Alkali Salt Marsh (CSM). This Salinas seri
e
s
p
r
e
s
e
n
t
l
y
s
u
p
p
o
r
t
s
a
l
l
three of these habitat types in the Upper Agua Hedionda Lagoon b
a
s
i
n
,
a
p
p
r
o
x
i
m
a
t
e
l
y
2
/
3
mile downstream. Salinas soil is the soil type where the CSM pro
p
o
s
e
d
f
o
r
i
m
p
a
c
t
o
c
c
u
r
s
.
Which one of these habitat types will occur in Salinas soil appears t
o
b
e
a
f
u
n
c
t
i
o
n
o
f
t
h
e
quantity and regularity of moisture available.
4.0 Conclusions
Freshwater marsh occurs in open bodies of fresh water with little c
u
r
r
e
n
t
f
l
o
w
,
s
u
c
h
a
s
ponds, and to a lesser extent around seeps and springs. Regular
l
y
s
a
t
u
r
a
t
e
d
s
o
i
l
i
s
necessary to sustain fresh water marsh. Riparian Scrubs are found al
o
n
g
r
i
v
e
r
s
,
s
t
r
e
a
m
s
,
and intermittent drainages throughout Southern California. SWS
c
a
n
s
u
r
v
i
v
e
l
i
m
i
t
e
d
drought, moderate alkalinity and moderate saline conditions. C
i
s
m
o
n
t
a
n
e
A
l
k
a
l
i
M
a
r
s
h
occur in low-lying areas with a high water table and alkaline soi
l
s
.
C
S
M
c
a
n
s
u
r
v
i
v
e
d
r
y
summer and autumn conditions provided that soils are salty enoug
h
t
o
d
i
s
c
o
u
r
a
g
e
competition from taller plants that would out-compete CSM for
a
v
a
i
l
a
b
l
e
w
a
t
e
r
a
n
d
sunlight. Suitable CSM soils typically have a salty crust in locati
o
n
s
w
h
e
r
e
p
o
n
d
e
d
w
a
t
e
r
has evaporated from the surface.
In the mitigation areas of Basin BJB the soil type is suitable to support the three
h
a
b
i
t
a
t
types to be revegetated. Basin BJB also appears to have the hydrologic resourc
e
s
t
o
support these three habitat types. It is proposed that the mitigation installation
l
o
c
a
t
e
freshwater marsh near the upstream mouth of the proposed desiltation basi
n
,
i
n
a
n
a
r
e
a
excavated low enough to allow ground water to regularly saturate the area. I
n
b
a
s
i
n
locations where the mitigation area is widest and furthest removed from th
e
e
x
i
s
t
i
n
g
stream channel, CSM. is proposed for installation. This location is the most
l
i
k
e
l
y
t
o
produce the conditions necessary to sustain this habitat type. Southern willow
s
c
r
u
b
i
s
proposed for location central to the mitigation site where moisture should b
e
g
e
n
e
r
a
l
l
y
available for most of the year.
Given the existing site conditions and the site preparation proposed, the habit
a
t
t
y
p
e
s
t
o
b
e
revegetated appear likely to establish and sustain in Basin BJB.
1 L1' Ii t-.i- III
Previously Permitted 1plPoc
Agriculture lmpocts\ ,
' Et.jc Woodland
III Salt tvlcirsli lrria)ct -•.1i
'H
NH
jI
'
I
YN
if IN
if
14
If
nch Carl
I I Mo lle>>t
i. 1'
LEGEND
1111 PREVIOUSLY PERMITTED IMPACTS
PROPOSED IMPACTS/MITIGATION SUMMARY
mitigation symbol habitat type acres ratio proposed
CISMONTANE SALT MARSH 0.04 5:1 0.20*
AGRICULTURE ' ' 0.03"no no
EUCALYPTUS WOODLAND 0.03 no 0.03**
* Salt marsh mitigation includes transplanting of (14) spiny rush (Juncus acutis spp, Leopoldii). ** Replacement of Eucalyptus woodland w/ So. willow scrub at 1:1 ratio proposed.
0 25 50 100 Fr
NORTH SCALE
Figure 1
Cannon Road Realignment Impacts Map PS NO 091148 4/27/04
Cannon Road Reach 3 11' JI
" lI WWWOOO
10 000000
---I--
R I
CaIave Hits I
Phas II&
/
h I
Buffer I
lv~
>— Vegetation
\
00 as
- 0 so
Proposed
Mitigation
Site
Detention
Basin BJB
0 75 150 300Fr Legend
symbol plant community type acres
NORTH 1 = 300' Proposed Wetland Creation Area 0.23*
Appro.ed Mitigation Area 8.30
Existing Wetands
I I Detenton Basin BJB
Total Created Wetlands 8.53
* Spiiy rush transplants will be located
in :he proposed Wetland Creation Area. Figure 2
Mitigation Plan 011 ffadmv~
Cannon Road Reach 3 is ,a.gsT £,fl Sw t CaEflsD. as
PS 991146 4/27/04
5.0 References
Bossard, C.C., Randall, J.M., and Hoshovsky, M.C., Editors, 2000, Invasive Plants of
California Wildiands. University of California Press, Santa Rosa, CA. 360 pp.
Dale, N., 1986, Flowering Plants of the Santa Monica Mountains, Capra Press, Santa
Barbara, CA. pp. 236.
Faber, P.M., and Holland, R.F., 988, Common Riparian Plants of California. Pickleweed
Press, Mill Valley, CA. pp. 140.
Glen Lukos Associates, December 9, 2002, Assessment of Additional Jurisdictional Impacts
Relative to Revised Grading Limits for the Cannon Road Reach 3 (Site 2) Road Crossing
Glen Lukos Associates, March 18, 2002, Jurisdictional Delineation of the College Boulevard
Reach A and Cannon Road Reach 3 Road Crossings at Calavera Hills, San Diego
County, California
Hickman, J.C., Editor, 1993, The Jepson Manual, Higher Plants of California. University of
California, Berkeley, CA; pp. 1392.
Holland, R.F., 1986, Preliminary Description of the Terrestrial Natural Communities of
California, Unpublished technical report. State of California, The Resources Agency,
Department of Fish and Game, Natural History Division, Sacramento, CA.
O'Day Consultants, July 31, 2002, Carlsbad Tract No. CT 00-02 Grading Plans for Cannon
Road
Recon, April 3, 2002, Final Habitat Restoration and Monitoring Plan for the City of Carlsbad
Bridge & Thoroughfare District No. 4, The Calavera Hills Project, and the Detention
Basins Project in Carlsbad, California
Recon, November 2001, Final Environmental Impact Report (EIR No. 98-02)(SCH No.
99111082) Calavera Hills Master Plan Phase II, Bridge and Thoroughfare District NO. 4,
& Detention Basins
Reiser, Craig H., Rare Plants of San Diego County, Aquafir Press, Imperial Beach CA
Sawyer, J.O. and Keeler-Wolf, T.,1995, A Manual of California Vegetation. California Native
Plant Society, Sacramento, CA. pp. 471.
U.S. Department of Agriculture, Growers Weed Identification Handbook. Publication
Number 4030, University of California, Oakland, CA.