HomeMy WebLinkAboutCT 97-09; La Costa Lucky Sav-On Shopping Center; Tentative Map (CT) (11)Vegetation Analysis
Wetland Determination
for
La Costa Plaza
Carlsbad, California
September 16.1997
Prepared for:
American Stores Properties, Inc.
6565 Knott Avenue
Buena Park, CA
90620-1158
Prepared by:
Vegetation Analysis
Wetland Determination
for
La Costa Plaza
Carlsbad, California
September 16.1997
TABLE OF CONTENTS
1.0
2.0
3.0
4.0
5.0
6.0
Summary of Findings
Introduction
Methods and Survey Limitations
Results
4.0.1 Wetland Determination
4.0.2 Botany - On-site Habitats
4.0.3 Botany - Off-site Habitats
Rare / Endangered Species
Sensitive Habitats
References
Wetland Determination Form
1
2
2
4
4
7
8
10
12
14
15
Appendix A - Plant Species List
Prepared for:
American Stores Properties, Inc.
6565 Knott Avenue
Buena Park, CA
90620-1158
Prepared by:
« . c > RECEIVEDPlanning Systems:
Greg Evans, Landscape Architect LA #3900
Fred Sproul, San Diego County Certified Biologist SEP 1 6 1997
2111 Palomar Airport Road, Suite 100 £ITV nn rAot CQAP*
ParkhaH PA Q^OOQ vrAKLotlADCarlsbad, CA 92009 PUNNING DEPT.
Vegetation Analysis
Wetland Determination
La Costa Plaza
Carlsbad, California
September 15,1997
1.0 Summary of Findings
This report provides an analysis of vegetation and wetland determination along the
San Marcos Creek corridor where it is adjacent to the northern property line of La
Costa Plaza in Carlsbad, California. La Costa Plaza is an existing commercial
development vegetated with ornamentals. The biological character of the creek
corridor was studied to a distance of 3007 from the property line, and mapped to
within approximately 2007 of the property line. In this area San Marcos creek has
been channeled by past development, and the vegetation that presently exists is
significantly dominated by non-native, weedy species. Several wetland plant
communities occur along the channel. The wetland delineation line occurs no
closer than 15' from the northern property line, and parallels the creek at an
approximate elevation of 8 feet MSL. Development within the property line should
not significantly impact these wetland plant communities. Upland vegetation that
occurs both on-site and off-site is not considered sensitive, except for a very small
area of off-site Disturbed Coastal Sage Scrub that will not be significantly affected by
proposed development.
Based upon the data collected during this biological assessment, it is our opinion
that no significant adverse direct or indirect biological impacts will occur to
sensitive biological resources in San Marcos Creek or Batiquitos Lagoon due to the
proposed project. The indirect impacts that may occur due to the proposed project
presently occur in large measure due to surrounding development. The additional
indirect impacts caused by the proposed project are insignificant adverse impacts.
La Costa Plaza VegetationAnalysis / Wetland Determination 1
2.0 Introduction
The subject property exists in a densely developed portion of Carlsbad. It is located
at the northeastern intersection of El Camino Real and La Costa Avenue, an area
affected by the 100 year flood plain of San Marcos Creek. The property is bordered to
the north by San Marcos Creek, to the west by El Camino Real, to the south by La
Costa Avenue and to the east by commercial development. The property exists
entirely as a commercial development, with over 99% of the property is occupied by
ornamental vegetation, buildings and support infrastructure. The area surveyed as
the subject of this report is on-site, adjacent to the northern property line, and an
area within 100 yards of the property line. The survey area was inventoried to
document vegetation species present, with a focus on plant community
classification, sensitive species identification, and wetland determination.
EXISTING CONDITIONS
The project site exists as a commercial development built on sandy loam soils that
slope northward to the existing San Marcos Creek. Natural drainage patterns have
historically carried all of the storm water runoff from the project site into the creek.
Along the northern property line and in the creek bottom, tidal influences have
occurred in the past. The soils within the creek influence range from clay to very
fine sand. The northern side of the creek across from the project site is also
developed, and is used as overflow parking for the La Costa Resort. The creek
carries water year-around, and is the primary freshwater source for Batiquitos
Lagoon to the west across El Camino Real. Upstream of the property, intensive
urban development occurs within the watershed of the creek, which encompasses
many square miles.
3.0 Methods and Survey Limitations
The property was surveyed in March, 1997, and again in August, 1997 by Fred
Sproul, botanist, and Greg Evans, Landscape Architect, LA #3900. Generally, the
La Costa Plaza VegetationAnalysis / Wetland Determination 2
Base: USGS 7.5 minute Encinrtas Quadrangte, CA.
NORTH LEGEND
1000 2000
I—SCALE (in ted
4000 LOCATION OF SITE
Exhibit 1
Vicinity Map
Carlsbad, California
La Costa Plaza VegetationAnalysis / Wetland Determination
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only native vegetation in the area is the narrow band of mostly disturbed native
vegetation that occurs along the creek. This creek habitat and sensitive biological
resources nearby are the focus of this study.
The study area was assessed to determine the location of native plant communities,
and tape measurements were collected to provide accuracy whenever sensitive
species or habitats were encountered. Vegetation was assessed by listing all plant
species encountered, noting the relative percentage of plants which were dominant
within each plant community.
In addition to the survey of vegetation associated with the San Marcos Creek
Corridor, a wetland determination was conducted to definitively locate sensitive
wetland habitats adjacent to the site. Vegetation and other wetland indicators were
recorded and mapped. A data form as provided in the 1987 Corps of Engineers
Wetlands Delineation Manual is attached.
4.0 Results
4.0.1 WETLAND DETERMINATION
Site Conditions
The developed property is a pad that slopes south to north, abruptly transitioning
into a channeled creek north of the property line. Downstream, it passes beneath a
bridge over El Camino Real, and then enters Batiquitos Lagoon. The regularly
channeled condition along this portion of San Marcos Creek is the result of
previous development of this area. A topographical cross section of the channel
proceeding from south to north is as follows:
a) the existing developed, sloping La Costa Plaza pad,
b) a north facing fill slope (reinforced by rip-rap),
c) a low shelf (approx. 30' - 40' wide), or a deposit area for dredged spoils,
(occurring on La Costa resort property),
La Costa Plaza VegetationAnalysis / Wetland Determination
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d) open water, (regularly channeled, approx. 507 wide)(La Costa Resort property),
e) a south facing fill slope
f) a fill pad that is developed (La Costa Resort property).
An outlet for sheet drainage from the existing parking lot exists approximately 375'
east of the El Camino Real bridge. Along this stretch of channel, approx. 375 linear
feet of rip-rap reinforced fill slope occurs, below which lies a low shelf of sandy
deposit material. It appears that the rip-rap reinforced fill slope is designed to
control erosion associated to the parking lot sheet drainage outlet. The low shelf
may be underwater only briefly during seasonal events, being higher than the
perennial water level in the creek. Just east of this drainage outlet, a deposit area for
dredged spoils exists at approximately the same elevation as the adjoining
developed pad, (see Vegetation Resources Map).
The slope, the shelf and the bank of San Marcos Creek are mostly dominated by
native plant species that have established since the channel was constructed and the
property developed.
Each of these three topographic features supports a distinctive vegetative cover.
1. Fill Slope Vegetation - Within the rip-rap area of the fill slope bank, very
little vegetation exists. Where rip-rap is absent, one of the following plant
communities may occur: 1) Baccharis scrub, 2) Upper Salt Marsh, 3) Ruderal,
or Ornamental vegetation.
2. Shelf Vegetation - The shelf is most prominently covered with a highly
disturbed Upper Salt Marsh plant community more accurately termed
Wetland Ruderal. Several young willow trees and young mulefat shrubs also
occur on the shelf. Baccharis scrub also occurs on the shelf, until wetland
conditions closer to the bank completely exclude this upland community
from establishing.
La Costa Plaza VegetationAnalysis / Wetland Determination
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3. Bank Vegetation - The bank of San Marcos Creek is considered Freshwater
Marsh. It is bordered with a band of Cattail (Typha dominguensis) that exists
on both sides of the creek. Several individual Arroyo willow trees (Salix
lasiolepis) also occur in this bank area. These trees occupy a small area, and
do not form an extensive continuous canopy. Cattails and Arroyo willows
are indicative of both the permanence and elevation of perennial freshwater
in the channel. There appears to be little to no influence from either
saltwater or its tidal fluctuations on the hydrology of this site.
Wetland Boundary Determination
The wetland boundary is determined by the limit of obligate wetland plant species,
wetland hydrology, and wetland soil characteristics. This zone occurs in the creek
channel mostly in locations where grade changes are acute, (see Vegetation
Resources Map). This zone encroaches up-slope near the parking lot drainage outlet
where a small stand of Upper Salt Marsh occurs. On the south bank, adjacent to the
proposed project, five plant communities occur, at least in part, within the wetland
zone. Fresh water marsh, Upper Salt marsh, Southern Willow Scrub, Mulefat
Scrub, Baccharis Scrub, and Wetland Ruderal plants. Soils in these areas have a
dark anaerobic character typical of permanent wetland conditions. Hydrologic
indicators do not show recent flooding or inundation of this area.
Turisdictional Authority
The Federal Clean Water Act (CWA) regulates activities that affect Wetlands and
Waters of the United States as defined by the 1987 Wetland Delineation Manual.
Under Section 404 of the CWA, the U.S. Army Corps of Engineers regulates and
issues permits for the disposal of dredge of fill in wetlands. Nationwide permits
exist for minimal impacts such as those below 1/3 acre to 3 acres in size. More
extensive impacts require Individual Permits, including extensive analysis and/or
mitigation. Individual permits are required when activities that impact wetlands
exceed three acres.
La Costa Plaza VegetationAnalysis / Wetland Determination
Section 401 of the CWA regulates any other discharges that may affect water quality
are regulated by the California Regional Water Quality Control Board (CRWQCB).
CRWQCB application and certification procedures require that an analysis and
report be made of the types of pollutants expected from the project Mitigation
usually requires the project to minimize or eliminate such impacts.
The California Department of Fish and Game (CDFG), regulates alterations to the
stream bed of wetland habitats under the Fish and Game code, sections 1600-1607.
After consultation with CDFG, impacts are permitted for removal and/or alteration
of wetlands. If a 1600 agreement is reached, mitigation is often required to reduce
project created impacts to a level of insignificance.
4.0.2 BOTANY - On- site Habitats
The on-site plant communities of the study area that were encountered are
described and area quantities are provided below.
Baccharis Scrub (BS) - (0.04 acres)
Baccharis Scrub is an upland scrub community that is most frequently found in dry
washes and disturbed areas. The species of Baccharis on the site is Coyote Brush
Baccharis pilularis var. consanguinea. The only other plant associate of note is
goldenbush, Isocoma veneta. This community occupies disturbed areas in drier and
upland areas of the site. No sensitive plants or animals are known or expected to
use this habitat within the study area.
Ruderal Vegetation (RU) - (0.01 acres)
Ruderal Vegetation occurs on the site in waste areas along the northern-most edge
of the property. The plants that have invaded this area are weedy annual grasses
such as Wild Oats (Avena sp.) and Black Mustard (Brassica nigra). No remnants of
the former native vegetation persists in these areas, and there is no particular
importance of this habitat to any sensitive flora or fauna.
La Costa Plaza VegetattonAnalysis / Wetland Determination
Disturbed (PIS) - (0.06 acres)
An area where dredge spoils and vegetative garbage are dumped occurs along the
eastern-most portion of the study area. Here random mounds of dirt and debris,
have been discarded and left unmodified. The few plants thriving in this area are
upland ruderal species.
Developed
Remaining portions of the study area support the ornamental plants that attend the
development.
4.0.3 BOTANY -Off-site habitats _
Six native plant communities of note occur off-site, none closer than 10' from the
northern property line of the subject parcel. These communities were generally in a
disturbed, and transitional state, due to the highly variable environmental
conditions that exist along stream course banks. Observed were: Baccharis Scrub,
Disturbed Diegan Coastal Sage Scrub, Upper Salt Marsh, Freshwater Marsh,
Southern Willow Scrub, and Mulefat Scrub. Also observed were Open Water and
Disturbed River Bank, wetland environments not supporting plants. Other non-
native habitats include: Wetland Ruderal species, Ruderal species, Disturbed areas,
Ornamentals and other Developed conditions.
Baccharis Scrub (BS) - Off-site Baccharis scrub occurs in the vicinity of the rip-rap
reinforced slope and on the low shelf downstream of the parking lot drainage
outlet. This upland shrub community is dominated by Coyote Brush, (Baccharis
pilularis var. consanguinea) and Coast goldenbush (Isocoma menziesii var.
vernoides). Other prominent plants include: Australian saltbush (Atriplex
semibaccata) and Tree tobacco (Nicotiana glauca).
Disturbed Diegan Coastal Sage Scrub (DSS) - - A small pocket of DSS that includes
sagebrush, (Artemesia calif ornica) occurs no closer than 10' from the project
La Costa Plaza VegetationAnalysis / Wetland Determination 8
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property line, slightly east of the drainage outlet. This community contains at
least 40% weedy species.
Upper Salt Marsh -(USM) - An inclusion of pickleweed, (Salicornia virginica) occurs
no closer than 10' from the project property line, near the mouth of the sheet
drainage outlet. A thin band of upper salt marsh (approx. 2'-4' wide) occurs
intermittently along the north bank of San Marcos Creek, east of the ECR bridge.
West of the bridge, upper salt marsh occurs in various degrees of disturbance
primarily outside of the study area where fresh water inundation does not occur.
Southern Willow Scrub - (SWS) - Two small dumps of Arroyo willows, Salix
lasiolepis. occur just east of the bridge crossing, on the shelf previously described.
One live tree and many dead willow trees occur west of the bridge crossing,
probably indicating that freshwater inundation or saltwater intrusion is
progressively limiting their establishment
Mulefat Scrub - (MS) - Two clumps of mulefat scrub occur on the shelf, one near the
existing drainage outlet.
Freshwater Marsh - (FM) Cattail, Tvpha latifolia. occurs no closer than 35' from the
I project property line, primarily in a narrow band along the creek bank. The
_ width (approx. 8' each side) of this band of cattails indicates a narrow band of
• permanently wet soil conditions along the creek edge. Cattails also occur on
mid-channel deposits in the study area.
Wetland Ruderal (WR) - Various herbaceous wetland ruderal species occur
* interspersed among the other off-site wetland communities. The shelf is most
I prominently covered with a highly disturbed Upper Salt Marsh plant
community of Pickleweed and Alkali heath (Frankenia salina). Several invasive
non-natives occur on the shelf, such as: Russain thistle, (Salsola tragus). Salt
cedar (Tamarix sp.). Pampas grass (Cortadiera sp.). Bristly ox-tongue (Picris
La Costa Plaza VegetationAnalysis / Wetland Determination 9
echoides) and Spiny clotbur (Xanthium strumarium). Extensive wetland ruderal
conditions occur west of the bridge.
Ruderal (RU) - Ruderal conditions, (invasive, non-native, weedy species),
predominate in the upland areas of creek influence in areas once occupied by
native plants. This disturbance is the result of past development that has
occurred on both sides of the creek.
5.0 Rare/ Endangered Species
The Federal and State Endangered species, (Sterna antillarum browni). California
Least Tern is being re-established at Batiquitos Lagoon. Nesting areas have been
created and successfully colonized in several locations around the lagoon, the closest
being an island colony located approximately 1400 feet from the nearest portion of
the proposed project, (median construction along El Camino Real). Because their
nesting requirements are very specific, it is unlikely that any nesting birds would
occupy areas closer to the project than this island. However, California least terns
have been known to utilize freshwater areas similar to San Marcos Creek for
foraging. Because of the sensitivity of this species, protection of potential foraging
areas is necessary.
The project proponent has designed a project that completely avoids all
encroachment into the existing creek corridor, except for storm water runoff, to be
discharged in a controlled manner. The existing commercial development
presently discharges storm water runoff into the creek, and does not use current
technology to purify the water leaving the site. The proposed drainage system will
use a desiltation basin, and a filtration system that is satisfactory to the California
Regional Water Quality Control Board (CRWQCB). The water released by the
proposed project will be of substantially higher quality than what is presently
discharged. Provided that runoff entering the creek does not contain harmful
pollutants, as defined by the CRWQCB, no significant adverse impacts are
La Costa Plaza VegetationAnalysis / Wetland Determination 1 0
anticipated to bird populations, and specifically the California least tern due to the
proposed project.
Southern Willow Scrub habitat, where it is of much greater scale and associated
with more extensive riparian systems, is known to support several sensitive bird
species, including the Federal and State Endangered (Vireo pusillus bellii). Least
Bell's vireo and the Federal Endangered (Empidonax traillii extimus). Southwestern
Willow flycatcher. However, the several willow individuals near the site are not
extensive enough to provide significant nesting or foraging opportunities. The
largest nearby riparian system containing extensive Southern Willow Scrub is in the
Green Valley corridor, just south of the project site. Only one Least Bell's vireo has
been observed in recent years in that 38 acre willow stand. This bird was not
detected again, leading the project biologists to conclude that the bird was just
migrating through the area. Neither of these species are expected to use SWS
habitat in the vicinity of the project site.
Freshwater marsh habitat, where it is associated with large saltmarshes may support
the Federally and State Endangered (Rallus longirostris leviper). Light-footed
clapper rail. The eastern basin of Batiquitos Lagoon is habitat for this bird species.
However, the San Marcos Creek channel is not suitable for nesting or foraging
because of the following factors . The creek is narrow, with a linear band of cattails
primarily along the bank, not the extensive cover that rails require. The bridge over
El Camino Real is a substantial impediment, blocking rail access to the creek.
Saltmarsh is habitat for the State Endangered (Passerculus sandwichensis beldingi).
Bering's Savannah sparrow. The saltmarsh along San Marcos Creek is seriously
degraded with invasive, non-native species, and is discontinuous with salt marsh
habitat in Batiquitos Lagoon. It is that Belding's Savannah Sparrow would use the
San Marcos Creek area to any significant degree.
La Costa Plaza VegetationAnalysis / Wetland Determination 1 1
6.0 Sensitive Habitats
Habitats considered biologically sensitive by the CDFG occur entirely outside of the
property line. However, within the study area several sensitive habitats occur,
including: Southern Willow Scrub, Freshwater marsh, Upper Salt Marsh, Mulefat
Scrub, and Disturbed Coastal Sage Scrub.
Of these, the only upland community present is Disturbed Coastal Sage Scrub. The
very small size (0.03 acres), its discontinuity with and other coastal sage scrub and its
highly disturbed nature, are circumstances that make it insignificant for use as
habitat by (Polioptila californica californica). California Gnatcatcher. No California
gnatcatchers are expected to use the site.
The wetland resources that are the subject of this study, though very small in area,
are adjacent to a large estuary system at Batiquitos Lagoon. This lagoon supports
threatened and endangered species. The water that flows in San Marcos Creek is a
primary source of the freshwater that enters Batiquitos Lagoon. The quality and
quantity of freshwater entering the lagoon substantively affects the biological quality
of this resource. The entire project area of 11.78 acres drains storm water into San
Marcos Creek. To the extent that this water is free of contaminants, as regulated by t
he CRWQCB, the biology of the lagoon should not be substantively affected.
7.0 Anticipated Project Impacts
The project as proposed does not develop areas outside of the property line. No
sensitive habitats are proposed for disturbance by the project. The only direct
impacts that may result from the proposed project would result from water quality
and flood control issues. The project as designed will potentially discharge increased
runoff, because of a larger area of impermeable surfaces proposed by the project.
However, the proposed increase in impermeable surface area is only a few thousand
square feet, whereas the total watershed of San Marcos Creek is many square miles.
The impermeable surface area as a percent of the entire watershed area is
insignificant. Therefore, an increase in the magnitude of freshwater entering the
La Costa Plaza VegetationAnalysis / Wetland Determination 1 2
lagoon is not a potential significant adverse impact to the existing habitat in the
study area or the lagoon itself. The storm water runoff that would issue from the
project would be within CRWQCB standards, and would be much cleaner than the
present discharge, which enters San Marcos Creek totally unfiltered.
Indirect impacts may result from noise and other factors because of the proximity of
habitat to the proposed development. Indirect impacts currently occur to the
natural habitat of the study area. Furthermore, these impacts are cumulative; they
occur as a result of pre-existing development of properties north, south, and east of
this site, and area mostly unmitigatable.
Sensitive bird species inhabit the Batiquitos Lagoon, but only the California Least
Tern may potentially use the open water habitat within the study area. This habitat
is likely to be used for foraging purposes only. The possibility exists that certain
construction activities may limit least tern use of the habitat. The foraging habitat
within the study area is a small portion of their overall foraging range at Batiquitos
Lagoon. The actual affect of slightly reduced foraging opportunities during project
construction is not likely to be an adverse significant impact.
Based upon the data collected during this biological assessment, it is our opinion
that no significant adverse direct or indirect biological impacts will occur to
• sensitive biological resources in San Marcos Creek or Batiquitos Lagoon due to the
™ proposed project. The indirect impacts that may occur due to the proposed project
• presently occur in large measure due to surrounding development. The additional
indirect impacts caused by the proposed project are insignificant.
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La Costa Plaza VegetationAnalysis / Wetland Determination 1 3
References
Abrams, L. 1923. Illustrated Flora of the Pacific States. Stanford University Press,
Stanford, California.
Beauchamp, R. M. 1986. A Flora of San Diego County. California. Sweetwater Press,
National City, California.
Holland, R. F. 1986. "Preliminary Descriptions of the Terrestrial Natural
Communities of California." Nongame-Heritage Program, California Department
of Fish and Game.
Hickman, J. C. 1993. The Tepson Manual. Higher Plants of California. University of
California Press, Berkeley, California. 1400 pp. + 1 p. errata
Munz, P. 1974. A Flora of Southern California. University of California Press,
Berkeley, California. 1086 pp.
Skinner, M. W. and Pavlik, B. M. 1994. California Native Plant Society's Inventory
of Rare and Endangered Vascular Plants of California. Special Publication No. 1
(Fifth Edition), California Native Plant Society, Sacramento, California. 338 pp.
Thomas Bros. Maps, 19%. The Thomas Guide. 1997.
La Costa Plaza VegetationAnalysfe / Wetland Determination 1 4
Exhibit 2
Wetland Determination Form
DATA FORh 1
DETERMINATION
Applicant " Application ?rojeet
Number: Name:
State; C/4" County: & & Legal Description: Iovrtshtp;A25 Range; *4 U/
Date; ^"ZS-^"! Plot No.; /V/M" _ Section:
Vegetation [list the three dominant species in each vegetation layer (5 If
only I or 2 layers)]. Indicate species with observed morphologic*! or knovn
physiological adaptation* vich an asterisk.
Indicator Indicator
Status Species Status
6. *&«*+ S*C.. ?) 12.
Z of species that «r» OBL, FACW. and/or FAC?V^vC»Other indicators
Hydrophytic vegetation: Yes XL_ No . B«»l«;
Series and phase ;^/*c«vfft*- ^^-j?" hy<lrlc soils list? Yes ; No
Mottled: Yes )C i No . Mottle color; ""— ; Matrix color;
Cleyed: Yes ?C So Other indicators; <^/<gycfg]C
Hydr.ic soils: Yes _JC No ; Basis; 5orf
Hydrology
Inundated: Yes : Ko f\ , Depth of standing water:
Saturated soils: Yes ; No .X- . Depth to saturated soil:
Other Indicators:
Wetland hydrology: Yea X ; No . Basis; ^/y/C
Atypical situation: Yes /^\ ; No . riSS O
Normal Clrcuastanos? Ye; No ^ ,
Wetland Deteraination: Wetland X^. ; Nonwetland_
Coaaents:
^ JDetermined by: CXxXgX
B2
La Costa Plaza VegetationAnalysis / Wetland Determination 1 5
APPENDIX A
Plant List
for
San Marcos Creek Wetland Determinatin
Carlsbad, California
APIACEAE - CARROT FAMILY
* Foeniculum vulgare
Sweet fennel
ASTERACEAE - SUNFLOWER FAMILY
Acourtia microcephala
Marsh fleabane
* Ambrosia psilostachya
Western ragweed
Artemisia californica
Coast sagebrush
Baccharis pilularis var. consanguinea
Coyote brush
Baccharis salicifolia
Mulefat
* Isocoma menziesii var. vernoides
Coast goldenbush
* Picris echoides
Bristly Ox-tongue
* Xanthium strumarium
Spiny clotbur
BORAGINACEAE - BORAGE FAMILY
Heliotropum curvassivicum
Alkali heliotrope
BRASSICACEAE - MUSTARD FAMILY
* Brassica nigra
Black mustard
CHENIPODIACEAE - GOOSEFOOT FAMILY
Atriplex brewerii
Brewer's saltbush
Atriplex patula spp. hastata
Halbeard-leaf saltbush
* Atriplex semibaccata
Austrialian saltbush
Salicornia vlrginica
Pickleweed
* Salsola tragus
Russian thistle
FRANKENIACEAE - FRANKENIA FAMILY
Frankenia salina
Alkali heath
OLEACEAE - OLIVE FAMILY
* Olea europea
Olive
SALICACEAE - WILLOW FAMILY
Salix lasiolepis
Arroyo willow
SOLANACEAE - NIGHTSHADE FAMILY
* Nicotiana glauca
Tree tobacco
TAMARICACEAE - TAMARISK FAMILY
* Tamarix sp.
Salt cedar
ANGIOSPERMS (MONOCOTS)
CYPERACEAE - SEDGE FAMILY
Scirpus olneyi.
Olney's bullrush
JUNCACEAE - RUSH FAMILY
Tuncus mexicanus
Mexican rush
POACEAE - GRASS FAMILY
* Cortadiera sp,
Pampas grass
* Cynodon dactylon
Bermuda grass
* Polypogon monspeliensis
Rabbit's-foot grass
TYPHACEAE - CATTAIL FAMILY
Typha dominguensis
Cattails
Status Plant Community
* Non-native (weed or cult.)
! Classified Sensitive
O Offsite in sphere area
DEC 2 * 1397
Supplement
Vegetation Analysis / Wetland Determination
for
La Costa Plaza
Carlsbad, California
December 18,1997
Prepared for:
American Stores Properties, Inc.
6565 Knott Avenue
Buena Park, CA
90620-1158
Prepared by:
Supplement
Vegetation Analysis / Wetland Determination
La Costa Plaza
Carlsbad, California
December 18,1997
1.0 Summary of Findings
The Lucky Save-on project presently proposed for the corner of La Costa Avenue
and El Camino Real has been amended to include a proposed earthen berm near
San Marcos Creek. The proposed earthen berm is designed to, reduce potential
flooding risk to a Leucadia County Water District facility. It is proposed for a
location adjoining the proposed Lucky Sav-on building, and extending eastward
adjacent to the stream channel, outside of the 100 year floodway. Additional
environmental analysis is necessary to adequately determine if the project as
presently proposed will impact significant biological resources. This report provides
an analysis of vegetation, of sensitive biological resources, and applies hydrology
conclusions reached by others, to assess the potential for significant environmental
impacts due to the project as presently proposed.
Based upon the data collected during this biological assessment, it is our finding that
no significant adverse direct or indirect biological impacts will occur to sensitive
biological resources in San Marcos Creek or Batiquitos Lagoon due to the project as
presently proposed. The indirect impacts that may occur due to the proposed project
presently occur in large measure due to surrounding development. The additional
indirect impacts caused by the proposed project are insignificant.
2.0 Introduction / Methods and Survey Limitations
The Planning Systems document, "Vegetation Analysis / Wetland Determination,
La Costa Plaza, September 16, 1997 provided a conclusion, "that no significant
adverse direct or indirect biological impacts will occur to sensitive biological
resources in San Marcos Creek or Batiquitos Lagoon due to the proposed project ".
The project as presently proposed is virtually the same except for the addition of an
earthen berm. Because the berm is the only substantive difference between the
previously analyzed plan and the current plan, this supplement will focus primarily
upon the berm and its potential environmental affect. When a finding regarding
the berm's environmental impact is reached, a cumulative project impact
assessment will then be provided.
The proposed berm is located on the south side of San Marcos Creek, outside of the
100 year floodway. It abuts the proposed Lucky Sav-on building to the west, and
extends easterly, parallel to the Creek (see Exhibit 2, O'Day Consultants "Preliminary
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
Grading Plan for L.C.W.D. Earth Berm, sheet 1 of 1, for location and configuration).
The berm, designed to serve as a flood control levee, is proposed as approximately
450 ft. long, approximately 44 ft. at its widest point, and a maximum of
approximately 9 ft. in height. Its is structurally comprised of 2:1 slopes, north and
south facing, with a 10' wide and flat top. Surface runoff from the flat top and the
south facing slope are designed to drain into control structures, surface runoff form
the north facing slope is seek the creek unassisted.
The berm is located almost entirely on L.C.W.D. property, with only a 10 ft wide
section located within La Costa Plaza property. A temporary 10 foot wide
construction zone is proposed to parallel the northern toe of slope, adjacent to the
creek (see O'Day Preliminary Grading Plan).
EXISTING CONDITIONS
The property was surveyed in March, 1997, and again in August, 1997 by Fred
Sproul, botanist, and Greg Evans, Landscape Architect, LA #3900. Generally, the
only native vegetation in the vicinity of the proposed berm is the narrow band of
mostly disturbed native vegetation that occurs along the creek bank. This creek-side
habitat and sensitive biological resources nearby are the focus of this study.
The berm is proposed entirely outside of the 100 year floodway, on relatively flat
land that is in no case lower than the 11 foot contour as shown on O'Day
Consultants Preliminary Grading Plan (Exhibit 2). Across San Marcos Creek on the
north bank is La Costa Resort Property, specifically a grassy area used for overflow
event parking. The lowest elevation along the north bank across from the berm is
approximately the 7 foot contour.
The site of the proposed berm was visited during the initial study, and vegetation in
the vicinity of the berm is shown on the "Vegetation Analysis Map" (September 10,
1997) as either "Disturbed", "Ornamental", or "Ruderal", or is a developed area of
the existing L.C.W.D. facility. No native plant communities exist beneath, or within
approximately eighteen feet of the proposed berm. No wetland habitat occurs
beneath or within 18' of the proposed berm.
Natural drainage patterns have historically carried all of the storm water runoff
from the berm site into the creek. Adjacent to the proposed berm, a dredge spoils
area composed of fill material, shown as "disturbed" vegetation on the Vegetation
Analysis Map, lies between the berm site and the creek bank. These spoils
effectively create a backwater bench that will initially pool run-off coming from the
north-facing berm slope, prior to unassisted release into the creek at low points
along the spoils bank.
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
3.0 Results
Hydrology
A hydraulic study to determine potential impacts of the proposed berm to San
Marcos Creek and adjacent properties has been conducted by Howard H. Chang
Consultants. The existing topographical configuration of the Creek area in the
vicinity of the proposed berm is structured such that bank overflow caused by large
flow events deposits backwater onto La Costa property on the north bank floodway.
The study has concluded that the proposed berm will not produce any change in the
scour potential of San Marcos Creek or the north bank overflow area within the
floodway (see exhibit I, Letter, Howard H. Chang Consultants, and the HEC-2 study
by Howard H. Chang Consultants). This finding indicates that berm construction
will not increase erosion in San Marcos Creek, or the floodway area, in the vicinity
of the proposed berm.
The wetland resources that are the subject of this study, though very small in area,
are adjacent to a large estuary system at Batiquitos Lagoon. This lagoon supports
threatened and endangered species. The water that flows in San Marcos Creek is a
primary source of the freshwater that enters Batiquitos Lagoon. The quality and
quantity of freshwater entering the lagoon substantively affects the biological quality
of this resource. The entire project area, including the north face of the berm, drains
storm water into San Marcos Creek. To the extent that this water is free of
contaminants, as regulated by the California Regional Water Quality Control Board
(CRWQCB), the biology of the lagoon should not be substantively affected.
Sensitive Habitats
No native plant communities exist on the land to be occupied by the proposed berm,
within the temporary 10' wide construction zone, or within 18' of the toe of the
berm. Provided that no construction activities occur outside the construction zone,
and that all exposed soils are properly planted and maintained, no disturbance of
existing native plant communities is anticipated, and no significant adverse impacts
are anticipated to native plant communities in the project vicinity.
Rare / Endangered Species
The Federal and State Endangered species, (Sterna antillarum browni), California
Least Tern, have been known to utilize freshwater areas similar to San Marcos
Creek for foraging. The location of the proposed berm should not affect water
quality, and would not in any way affect foraging opportunities for this species. No
significant adverse impacts are anticipated to the California least tern due to the
proposed berm.
Freshwater marsh habitat, where it is associated with large saltmarshes may support
the Federally and State Endangered (Rallus longirostris leviper), Light-footed
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
clapper rail. The eastern basin of Batiquitos Lagoon is habitat for this bird species.
However, the San Marcos Creek channel is not suitable for nesting or foraging
because the creek is narrow, with a linear band of cattails primarily along the bank,
not the extensive cover that rails require. The bridge over El Camino Real is .a
substantial impediment, blocking rail access to the creek. However, in the event
that Clapper rail were to utilize the creek adjacent to the project site, no freshwater
marsh habitat will be affect by the proposed berm. No significant adverse impacts
are anticipated to the Clapper rail due to the proposed berm.
The Federal and State Endangered (Vireo pusillus bellii), Least Bell's vireo and the
Federal Endangered (Empidonax traillii extimus), Southwestern Willow flycatcher
utilize Southern Willow Scrub (SWS) habitat. No SWS habitat will be affected by
the proposed berm, and no significant adverse impacts are anticipated to either of
•these species due to the proposed berm.
It is highly unlikely that the State Endangered (Passerculus sandwichensis beldingi),
Belding's Savannah sparrow would use the salt marsh area east of El Camino Real,
near the project site. No salt marsh habitat will be affected by the proposed berm, so
no significant adverse impacts are anticipated to this species due to the proposed
berm.
The Federally Threatened Polioptila californica californica), Coastal California
gnatcatcher occasionally utilizes ruderal or disturbed vegetation for foraging
purposes when it occupies an adjacent stand of Coastal sage scrub vegetation. A
small pocket of disturbed Coastal sage scrub (0.03 acres), that occurs near the berm
site is too small to be utilized by gnatcatcher, so no gnatcatcher foraging is expected
on the disturbed and ruderal plant communities on or near the berm site. No
significant adverse impacts are anticipated to this species due to the proposed berm.
4.0 Project Impacts
The previous section have concluded that the proposed berm will not significantly
affect the hydrology, sensitive habitats, or sensitive species associated with San
Marcos Creek. The only direct impacts that could be anticipated due to berm
construction are: 1) uncontrolled erosion during construction, 2) inadequate berm
planting / maintenance, 3) a minute increase in surface run-off associated with a
berm slope rather than the existing flat surface.
Provided that adequate silt fencing and construction work limit lines are
maintained, no significant adverse impacts due to construction related erosion are
anticipated. Provided that adequate erosion control berm planting and
establishment maintenance is implemented, no significant adverse impacts due to
establishment related erosion are anticipated. In terms of the minute increase in
run-off because of the berm slope, as evaluated against the total watershed of San
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
Marcos Creek which is many square miles, no significance impact due to increased
run-off is anticipated.
Indirect impacts resulting from construction noise and berm maintenance may
occur due to the proximity of the proposed berm to creek and near creek habitat.
These indirect impacts are either temporary construction related impacts,, or brief
maintenance related episodes occurring seldom and on an irregular basis. These
indirect impacts are insignificant and largely unmitigatable.
5.0 Cumulative Project Impacts
The studies that have occurred to date have found that no significant
environmental impacts to sensitive biological resources will occur due to the
proposed project. Thusfar, this study has focused on potential environmental
impacts associated with the berm only, not in terms of the total project proposed.
In cumulative terms, the finding of no significant impact is also appropriate.
The project does not significantly alter existing stream properties. No sensitive
habitats are proposed for disturbance by the project. No sensitive animals are likely
to be significantly impacted by the project as proposed.
Based upon the data collected during this biological assessment, it is our opinion
that no significant adverse direct or indirect biological impacts will occur to
sensitive biological resources in San Marcos Creek or Batiquitos Lagoon due to the
project as presently proposed. The indirect impacts that may occur due to the
proposed project presently occur in large measure due to surrounding development.
The additional indirect impacts caused by the proposed project are insignificant.
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
Exhibit 1
Letter, Howard H. Chang Consultants, December 11,1997
Howard H. Chang Consultants
! ' Hydraulic, Hydrolpgic and Sedimentation Engineering
P.O. Box 9492
Rancho Santa Fe, CA 92067
(619)756-9050. 594-6380. FAX: (619)756-9460 •
December 11, 1997
Ms. Meg Purviance
O'Day Consultants .
7220 Avenida Encinas, Suite 204
Carlsbad, CA 92009
Dear Meg:
i.
Subject: Revision of HEC-2 study for San Marcos Creek at La Costa for American Stores
I wish to provide you with the results of the hydraulic study in order to determine the
potential impacts of the proposed berm on adjacent properties. The proposed berm will be located
along the south bank of the main channel outside the floodway from river mile 2.80 to 2.84. In
order to determine if there is going to be any change in the scour potential, it is necessary tq look at
the flow velocities under the existing conditions without the berm and the proposed conditions with
the berm in place. The computed flow velocities for the main channel and north overbank area
within the floodway are summarized below.
Channel station
river mile
2.S1
2.83
2.85
2.89
2.93
Velocity in the main channel
fps
Existing
conditions
5.9
5.6
6.5
6.1
5.9
Proposed
conditions
5.9
5.6
6.5
6.1
5.9
Velocity in the north overbank area
fps
Existing
conditions
5.2
4.9
5.4
5.2 .
5.1
Proposed
conditions
5.2
4.9
5.4,
5.2
5.1
It can be seen from the computed velocities listed above that the proposed berm will not change the
flow velocity and hence it will not change the scour potential for the adjacent properties north of the
channel. '
Please let me know if you have any questions regarding this letter. .
i
CONSULTANTS " " ' :
DEC 15 1997
REOEIVED . Howard H.Chang. Ph.D., P.E.
Si
SUPPLEMENT - La Costa Plaza Vegetation Analysis / Wetland Determination
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Exhibit 2
PRELIMINARY GRADING PLAN
L.C.W.D EARTH BERM
LA COSTA PLAZA
CARLSBAD, CALIFORNIA
LEGEND
BERM LOCATION
PROPOSED LUCKY SAV-ON BUILDING
0 10 20 40
RTL
SOFT
40 SCALE NORTH
DECEMBER 23, 1997
GRADING PLAN / BASE SOURCE: O'DAY CONSULTANTS PS # 971248