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WETLAND DELINEATION REPORT
FOR THE SOUTH CARLSBAD VILLAGE
STORM DRAIN PROJECT
CITY OF CARLSBAD
SAN DIEGO COUNTY, CALIFORNIA
Prepared for:
CITY OF CARLSBAD
2075 Las Palmas Drive
Carlsbad, CA 92009
Contact: Douglas Helming
(760) 431-5999
Prepared by:
DUDEK & ASSOCIATES, INC.
605 Third Street
Encinitas, California 92024
Contact: Anita M. Hayworth, Ph.D.
(760) 942-5147
30 June 1997
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TABLE OF CONTENTS
Section Page
SUMMARY OF FINDINGS 1
1.0 DESCRIPTION OF PROJECT . . . . . 2
2.0 PURPOSE OF ASSESSMENT 2
3.0 ENVIRONMENTAL SETTING 2
4.0 METHODS 5
5.0 RESULTS 5
5.1 General Description of Wetland Habitat 5
5.2 Wetland Determination and Delineation 8
5.3 Wetland Functions and Values 8
6.0 DISCUSSION 9
6.1 Project Impacts 9
6.2 Regulatory Requirements 9
6.3 Mitigation 10
7.0 LITERATURE CITED 10
LIST OF FIGURES
Figure 1 Regional Map 3
Figure 2 Vicinity Map 4
Figure 3 Wetland Delineation Map - Existing Channel 6
Figure 4 Wetland Delineation Map - Storm Drain Outfall 7
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Wetland Delineation Report for the South Carlsbad Storm Drain Project
SUMMARY OF FINDINGS
Implementation of the proposed South Carlsbad Village Storm Drain project, in the City of
Carlsbad, San Diego County, California, would result in the permanent loss of approximately
0.63 acre (2,750 linear feet) of waters of the U.S., a habitat under the jurisdiction of the U.S.
Army Corps of Engineers (ACOE). The habitat potentially affected is a linear stretch of an
unvegetated drainage ditch along the A.T. & S.F. Railroad tracks within the City of Carlsbad.
The site is located within an urban area of the city and is surrounded by ruderal, disturbed and
developed lands.
No species of plants or animals recognized as rare, threatened, endangered, or otherwise
sensitive by the U.S. Fish and Wildlife Service (USFWS), California Department of Fish and
Game (CDFG), or California Native Plant Society are present within or adjacent to the drainage
area.
The total area within the project under the jurisdiction of the ACOE is approximately 0.63
acres. Implementation of the proposed development would result hi the permanent loss of 0.63
acre of jurisdictional habitat. Because impacts to waters are not less than an one-third acre and
the project impacts more than 500 linear feet of waters, it requires review by the ACOE prior
to use of one of the nationwide permits to cover impacts. No impacts to CDFG jurisdictional
area would occur, thus a Streambed Alteration Agreement pursuant to Section 1603 of the
California Fish and Game Code is not required. A Section 401 water quality certificate (or
waiver) would be required from the California Regional Water Quality Control Board.
Because of the low quality of the waters habitat to be impacted, it is recommended that a
replacement be created at a ratio of 1:1 by area. Hence, it is recommended that 0.63 acre of
wetland habitat be recreated or enhanced adjacent to Agua Hediona Lagoon.
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Wetland Delineation Report for the South Carlsbad Storm Drain Project
1.0 DESCRIPTION OF PROJECT
The South Carlsbad Village Storm Drain project involves construction of a backbone storm drain
system extending from Agua Hedionda Lagoon northward approximately 5,500 feet along the
alignment of the San Diego Northern Railroad right-of-way to Oak Avenue (Figure 1). The
proposed storm drain project will consist of a underground pipe from Oak Avenue to the
discharge at'Agua Hedionda Lagoon (Figure 2). The discharge structure may incorporate a short
section of concrete-lined channel to convey the flows to the lagoon. Energy dissipators will be
installed at the outfall. No discharge of dredged and/or fill material to the lagoon is expected.
Other portions of the storm drain system are located within existing development and contain
no biological issues to address.
The proposed storm drain from Agua Hedionda to Oak Avenue consists of replacement of the
existing dirt channel and possibly replacement of the existing pipe with the new line. The
replacement of the existing dirt channel would result in the permanent loss of "waters of the
U.S." which is under the jurisdiction of the U.S. Army Corps of Engineers (ACOE).
2.0 PURPOSE OF ASSESSMENT
The purposes of this assessment are to determine the boundary of U.S. Army Corps of
Engineers (ACOE) Section 404 jurisdiction and the boundary of the California Department of
Fish and Game (CDFG) Section 1601-1603 jurisdiction within the study area, if any; to
determine the acreage of impacts on these areas that would result from project implementation;
and to determine the resultant permits or approvals required.
3.0 ENVIRONMENTAL SETTING
The South Carlsbad Village Storm Dram project is located within the right-of-way of the A. T.
& S. F. Railroad within the urban area of the City of Carlsbad. The area is west of Interstate
5 and east of Carlsbad Boulevard and runs between Agua Hedionda and Oak Avenue.
The vegetation within the open, dirt channel, as it travels from Oak Avenue to Village Avenue
is composed of ruderal vegetation or disturbed habitat and consists predominantly of non-native
grasses and forbs as described in Section 5.0. The site is highly disturbed with little vegetation
and only three native plant species present within the channel. Elevations onsite range from
approximately sea level at the outfall to Agua Hediona to 40 feet above mean sea level. The
open channel is approximately 2,750 feet long and is approximately 10 feet wide and
approximately 6 feet deep. From Village Avenue south to the outfall to Agua Hedionda Lagoon,
the storm drain is underground and consists of a 63-inch reinforced concrete pipe. The area
above the concrete pipe is vegetated with non-native grasses and forbs or is devoid of vegetation.
The outfall from the existing pipe to Agua Hedionda Lagoon consists of a concrete-lined
channel, approximately 200 feet in length.
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South Carlsbad Village Storm Drain Project - Wetland Delineation Report
Regional Map
FIGURE
(^Reservoir ^"~""-—S , ^^ \ .y
\\ \\ \ \*^ _« = s=s^ "v, r"*
South Carlsbad Village Storm Drain Project - Wetland Delineation Report
Vicinity Map
\ \ \ \\A 2 A*
Unvegetated Concrete Channel
(10' wide X 6' deep)
Vegetation Types:
FWMl Freshwater Marsh
\ TOPO SOURCE: City of Carlsbad. Sheets 38 & 49
South Carlsbad Village Storm Drain Project • Wetland Delineation Report
Wetland/Waters Delineation Map - Existing Channel
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Wetland Delineation Report for the South Carlsbad Storm Drain Project
4.0 METHODS
A wetland determination was conducted on 30 May 1997 by Dudek & Associates, Inc., habitat
restoration specialist Jeff L. Thomas. During the survey, notes were taken on the wetland plant
communities present. Boundaries between wetland communities were mapped on a 200-scale
(1"=200') topographic map.
The U.S. Army Corps of Engineers Wetland Delineation Manual (1987) was used to determine
whether jurisdictional wetlands occurred within the study area. The manual requires that
positive indicators of hydric soils, wetland hydrology, and hydrophytic vegetation all be present
to classify an area as a jurisdictional wetland. Other "waters of the United States," as defined
by the ordinary high water mark of streams or drainages, also were identified and mapped in
the field.
Typically, where a predominance of hydrophytic vegetation is present, additional data on soils
and hydrology are collected, and a wetland data form is completed. However, owing to the
absence of a predominance of hydrophytic vegetation outside the ordinary high water mark of
the deeply incised channel, no wetland data forms were completed and no soil pits were
excavated. Isolated patches of hydrophytic vegetation were observed within the incised channel,
and were noted as wetland portions of "waters of the U.S."
The definition applied by the California Department of Fish and Game (CDFG) to determine the
presence of wetlands is less objective than that of the U.S. Army Corps of Engineers (ACOE).
Per CDFG, wetlands are defined as "a body of water that flows at least periodically or
intermittently through a bed or channel having banks and supports fish or other aquatic life."
"This includes water courses having a surface or subsurface flow that supports riparian
vegetation." Any area that met these criteria also was identified and mapped.
5.0 RESULTS
5.1 GENERAL DESCRIPTION OF WETLAND HABITAT
Areas under the jurisdiction of the ACOE and/or the CDFG are illustrated hi Figures 3 and 4.
Soils within the drainage are mapped as Marina loamy coarse sand, 2-9 percent slopes (MIC)
(Bowman 1973). Jurisdictional area onsite consists of a deep, incised maintained channel
draining from north to south within a City of Carlsbad right-of-way parallel to the railroad
alignment. The drainage consists of two open channels; an approximately 2750 foot earthen
channel between Oak Avenue and Village Drive (Figure 3), and a 200 foot concrete channel and
outfall at Agua Hedionda Lagoon (Figure 4). Storm water and urban runoff are carried between
the channel sections via a buried storm drain pipe. Both sections of the open channel consist
of a deep (6-8 feet below the surrounding land surface), incised, narrow (10 feet wide) drainage.
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AGUA HEDIONDA LAGOON
Vegetation Types:
I SM | Salt Marsh
I OW| Open Water
IRUDI Ruderal
I DH | Disturbed Habitat
|PEV| Developed
TOPO SOURCE: City of Carlsbad, Sheet 60
Unvegetated Concrete Channel
(10' wide X 8' deep)
200
Scale in Feet
South Carlsbad Village Storm Drain Project - Wetland Delineation Report
Wetland/Waters Delineation Map - Storm Drain Outfall
c
Wetland Delineation Report for the South Carlsbad Storm Drain Project
The northern channel section is predominately vegetated by ruderal non-native species or is
unvegetated, with channel banks occupied by ruderal or weedy habitat. The bottom of the
drainage supports two isolated patches of freshwater marsh (0.08 acre total), i.e., cattails (Typha
latifolid) and willow weed (Pofygonum lapathifolium), and scattered individuals of castor-bean
(Ricinus communis), curly dock (Rumex crispus), umbrella sedge (Cyperus involucratus), and
western ragweed (Ambrosia psilostachyd) amidst a wide distribution of prickly lettuce (Lactuca
serriola), wild radish (Raphanus sativus), Mexican tea (Chenopodium ambrosioides), garland
(Chrysanthemum coronarium), and Bermuda grass (Cynodon dactylori). Three of the plant
species observed hi the channel are obligate wetland species: cattail, umbrella sedge, and willow
weed, of which only the willow weed is a native plant species. It is unknown whether or not
portions of the drainage supported riparian habitat historically.
From Village Avenue south to the outfall to Agua Hedionda Lagoon, the storm drain is
underground and consists of a 63-inch reinforced concrete pipe. The area above the concrete
pipe is vegetated with non-native grasses (brome and wild oats), western ragweed, castor-bean,
and wild radish. The outfall from the existing pipe to Agua Hedionda Lagoon consists of a
concrete-lined channel, approximately 200 feet in length. There is no wetland vegetation within
the concrete channel. Adjacent to the outfall, the habitat consists of developed areas, disturbed
habitat, ruderal vegetation, and salt marsh. The salt marsh habitat is dominated by pickleweed
(Salicornia virginica).
5.2 WETLAND DETERMINATION AND DELINEATION
5.2.1 ACOE Jurisdiction
U.S. Army Corps of Engineers wetland habitat is present onsite consisting of freshwater marsh.
The incised channel, an intermittent blue line stream, represents "waters of the United States"
which is also under the jurisdiction of the ACOE. Total ACOE jurisdiction onsite is
approximately 0.63 acre of unvegetated and vegetated channel.
5.2.2 CDFG Jurisdiction
CDFG jurisdiction is typically calculated based upon the area of riparian vegetation, Because
the channel supports no significant riparian vegetation and there is no evidence of aquatic
wildlife, no CDFG jurisdictional wetland occurs in the study area.
5.3 WETLAND FUNCTIONS AND VALUES
A formal wetland functions and values analysis was not performed. Wetland habitat within the
study area is expected to have low value as wildlife habitat owing to its highly disturbed
condition and the lack of riparian vegetation. The drainages support exceedingly few
hydrophytic plant species (e.g., Pofygonum lapathifolium, Typha latifolia), and few birds forage
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Wetland Delineation Report for the South Carlsbad Storm Drain Project
within it. None of the typical southern California riparian birds (e.g., vireos, flycatchers,
woodpeckers) are present. Birds species observed most commonly include house finch
(Carpodacus mexicanus), lesser goldfinch (Carduelis psaltria), and mourning dove (Zenaida
macroura). The channel probably has few biotic functions.
No species of mammals were detected within the vicinity of the drainage. Mammals likely to
be present include those species adapted to disturbed or urbanized landscapes, including Virginia
opossum (Didelphis virginica), cottontail (Sylvilagus sp.), striped skunk (Mephitis mephitis),
California ground squirrel (Spermophilus beecheyi), and introduced rats (Rattus sp.).
No sensitive, threatened, or endangered species were observed in the drainage.
6.0 DISCUSSION
6.1 PROJECT IMPACTS
Impacts to waters of the U.S. would result from the implementation of the South Carlsbad
Village Storm Dram project. The entire open channel between Village Place and Oak Avenue
would be replaced with a pipeline to transport storm runoff to Agua Hedionda.
6.1.1 ACOE Impacts
Approximately 0.63 acre of ACOE jurisdictional waters would be permanently lost by project
implementation. The area is represented primarily by disturbed, non-vegetated habitat.
6.1.1 CDFG Impacts
No CDFG jurisdictional wetlands would be permanently lost by project implementation.
6.2 REGULATORY REQUIREMENTS
The discharge of dredge or fill material (temporary or permanently) into areas delineated as
"waters of the United States" requires authorization from the ACOE pursuant to Section 404 of
the Clean Water Act. "Waters of the U.S." as defined in CFR 328.2 includes all waters or
tributaries to waters, including wetlands, streams, dry washes, seasonal drainages, and other
aquatic habitats. Activities that involve regulated discharge of dredge or fill material include
grading, placing of riprap for erosion control, pouring concrete, laying sod, and stockpiling
excavated material. Activities that generally do not involve regulated discharge, if performed
in a manner to avoid discharge, include driving pilings and some methods of vegetation clearing.
Total ACOE jurisdiction to be impacted is 0.63 acre. The ACOE has 36 nationwide or general
permits (NWPs) that pre-authorize specific minor discharges. Generally, use of these NWPs
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Wetland Delineation Report for the South Carlsbad Storm Drain Project
does not require review by the ACOE or other federal agencies. If endangered species or
significant cultural resources occur on the property and are not adequately mitigated, the activity
is not considered pre-authorized and ACOE has the discretionary authority to require an
individual permit. The individual permit process involves public comment on the proposed
activity and can last 180 days or longer. Because impacts to ACOE jurisdiction are greater than
one-third acre and also greater than 500 linear feet, notification of the ACOE is required.
The applicant must also obtain a Section 401 water quality certification (or waiver) from the
California Regional Water Quality Control Board.
No impact to CDFG jurisdictional wetlands will occur as a result of the project, thus a CDFG
1603 agreement will not be required.
6.3 MITIGATION
Mitigation for impacts to ACOE jurisdiction takes several forms, including (1) avoidance of
impacts; (2) reduction of impacts; or (3) compensation for impacts. The proposed project would
impact a total of 0.63 acre of jurisdictional waters of the U.S. The ultimate determination of
mitigation, including the ratio, is subject to the discretion of the agencies. However, the
mitigation ratio should be commensurate with the low quality of wetlands onsite.
It is recommended that impacts to waters be mitigated at a ratio of 1:1 by area. Hence, 0.63
acre of wetland habitat should be created/revegetated adjacent to Agua Hediona Lagoon.
7.0 LITERATURE CITED
Bowman, R. H. 1973. Soil Survey of San Diego Area, California, Part 1. United States
Department of Agriculture, Soil Conservation Service and Forest Service. 104 pp.
Hickman, J. C. 1993. The Jepson Manual, Higher Plants of California. University of
California Press, Berkeley, Los Angeles, London.
Reed, P. B. 1988. National list of plant species that occur hi wetlands: California (Region 0).
U.S. Fish and Wildlife Service Biological Report 88 (26.10).
U.S. Army Corps of Engineers. 1987. Corps of Engineers Wetlands Delineation Manual,
Technical Report Y-87-1, U.S. Army Corps of Engineers Waterways Experiment Station,
Vicksburg, Mississippi.
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