HomeMy WebLinkAbout3416; AVENIDA ENCINAS EXTENSION; BIOLOGICAL RESOURCES REPORT; 1993-10-01BIOLOGICAL RESOURCES REPORT
AND IMPACT ANALYSIS FOR THE AVENIDAENCINAS EXTENSION
CITY OF CARLSBAD
SAN DIEGO COUNTY, CALIFORNIA
Prepared for:
CITY OF CARLSBAD
2075 Las Palmas Drive
Carlsbad, California 92009-1576
Contact: Pat Entezari
(619)438-1161 ext. 4385
Prepared by:
DUDEK AND ASSOCIATES, INC.
605 Third Street
Encinitas, California 92024
Contact: John W. Brown, Ph.D.
(619) 942-5147
1 October 1993
TABLE OF CONTENTS (continued)
6.0 MITIGATION MEASURES ...;. 14
7.0 ACKNOWLEDGEMENTS .................. .. . ......... 14
8.0 LITERATURE CITED ......14
LIST. OF APPENDICES
Vascular Plant Species Observed on the Project Site .
Wildlife Species Observed or Detected on the Project Site
Species Sensitivity Categories . .
Page
LIST OF FIGURES
Figure 1 Regional Map - Avenida Encnas Extension ...................4
Figure 2 Vicinity Map - Avenida Encinas Extension .....................5
Figure 3 Biological Resources - Avenida Encinas Extension ...........map pocket
LIST OF TABLES .
Table 1 Schedule of Surveys ....................................2.
Avenida Encinas Extension Biology Report
1.0 INTRODUCTION
Avenida Encinas is a two-lane paved road that roughly parallels Interstate Highway 5 between
Poinsettia Lane and Palomar Airport Road in the western portion of the City of Carlsbad, San
Diego County, California. Between Poinsettia Lane and Palomar Airport Road, Avenida
Encinas is interrupted by an approximately 0.25 mile stretch of former and active agricultural
land and adjacent disturbed habitat. The City of Carlsbad proposes to link the two disjunct
portions of Avenida Encinas so that it forms a continuous route from Poinsettia Lane in the south
to Palomar Airport Road in the north.
A biological survey of the proposed roadway alignment was conducted in July and August 1993
to assess the existing conditions of the biological resources. The purpose of this report is to
describe the biological character of the project site in terms of vegetation, flora, wildlife, and
wildlife habitats; analyze the biological significance of the site in view of federal, state, and local
laws and policies; quantity potential impacts of a proposed roadway; and provide mitigation
measures if deemed necessary to reduce impacts to biological resources below a level that is
considered significant.
2.0 METHODS AND SURVEY LIMiTATIONS
Data regarding biological resources present on the project site were obtained through a review
of pertinent literature and through field reconnaissance; both are described in detail below.
2.1 Literature Review
Sensitive biological resources present or potentially present within and adjacent to the proposed
alignment were identified through a literature search using the following sources: U.S. Fish and
Wildlife Service (1989, 1990, 1991), California Department of Fish and Game (1980, 1986,
1987), California Native Plant Society's Inventory of Rare and Endangered Vascular Plants
(Smith and Berg 1988), Murphy (1990), unpublished data from environmental reports (e.g.,
Dudek and Associates, Inc. 1993), and the vegetation and sensitive species mapping performed
for the City of Carlsbad's Habitat Management Plan. General information regarding wildlife
species present in the region was obtained from Unitt (1984) for birds, Bond (1977) for
mammals, Stebbins (1985) for reptiles and amphibians, and Emmel and Emmel (1973) for
butterflies.
2.2 Field Reconnaissance
Biological surveys of the alignment were conducted by Dudek and Associates, Inc. (DUDEK)
biologists John W. Brown (JWB), Ph.D., and Brock A Ortega (BAO) during July and August
1993 according the schedule illustrated in Table 1. All surveys were conducted by foot, under
favorable weather conditions. The entire alignment, from Palomar Airport Road to the Volvo
1
Avenida Encinas Extension Biolog)? Report
automobile dealership north of Poinsettia Lane (on Avenida' Encrnas), was visited and
inventoried for biotic components. ..
2.2.1 Resource Mapping
Plant communities were mapped in the field directly onto 100 scale (1" =100') topographic maps
of the site provided by the City of Carlsbad. A 400-scale (1" =400') oithotopographic map of
the area from the City of Carlsbad (dated September-October 1988) 'also was used for resource
mapping. Plant community classifications used in this report follow Holland (1986), with
modifications to accommodate the lack of conformity of the observed communities to those of
Holland. Locations of rare or sensitive plant and wildlife' species also were mapped, and the
numbers present were estimated. . . .
2.2.2 Flora
All plant species encountered during .the field surveys were identified and recorded. Those
species that could not be identified immediately were brought into the laboratory for further
investigation. Latin and common names of plants follow the Jepson Manual (Hickman 1993)..
Where -not listed in Hickman (1993), common names are taken from Beauchamp (1986). A list
of plant species observed within the alignment is presented in Appendix A.
2.2.3 Fauna
Wildlife species detected during field surveys by sight, calls, tracks, scat, or other sign were
recorded.. Binoculars (7 x 35 power) were used to aid in the identification of observed animals.
Records from previous biological studies and accounts from local residents also were consulted.
In addition to species actually observed, expected wildlife use of the site was determined by
Avenida Encinas Extension Biology Report
known habitat preferences of local 'species and knowledge of their relative distributions in the
area. A list of wildlife species observed or detected on-site is presented in Appendix B.
Latin and common names of: animals follow Stebbins (1985) for reptiles and amphibians,
American Ornithologists' Union (1983, 1989) for birds, Jones et al. (1982) for mammals, and
Emmel and Emmel (1973) for butterflies.
2.2.4 Sensitive Biological Resources
Sensitive biological resources are those defined as follows: (1) species that have been given
special recognition by federal, state, or local conservation agencies and organizations due to
limited, declining, or thráatened population sizes; (2) species and habitat types recognized by
local and regional resource agencies as sensitive; (3) habitat areas or plant communities that are
unique, are of relatively limited distribution, or are of particular value to wildlife; and 4)
wildlife corridors and habitat linkages.
During the field surveys a special effort was made to identify those areas suspected to support
sensitive resources. Surveys were conducted too late in the year for the detection of most
spring-blooming ephemeral plants. Because of the disturbed nature of the alignment and the
absence of coastal sage scrub, surveys for the federally-listed threatened California gnatcatcher
(Polioptila californica) were, not necessary.
3.0 PHYSICAL CHARACTERISTICS
3.1 Site Description
The Avenida Encinas Extension project is situated in the western portion of the City. of Carlsbad,
in western San Diego County, California (Figure 1). The project site lies west of Interstate
Highway 5,. at the northern edge of the USGS 7.5 minute Encinitas quadrangle (Figure 2).
Avenida Encinas extends northward from Poinsettia Lane approximately 0. 75 mile before it dead
ends. To the north of this point, the alignment crosses former agricultural fields 'and disturbed
habitat; much of the alignment is within an existing dirt road. The northern portion of the
alignment, extending approximately 0.5 mile south from Palomar Airport Road, consists mostly
of a paved two-lane road and disturbed habitat to the immediate west.
Topographically, the entire alignment is moderately level, varying only from about 50 to 60 feet
above mean sea level (AMSL). According to Bowman (1973), the following soils are present
on or adjacent to the alignment: Marina loamy coarse sand (M1C) and Huerhuero loam (HrC).
Soils of the Marina series consist of somewhat excessively drained, very' deep loamy coarse
sands derived from weakly consolidated to nOncoherent ferruginous eolian sand. These soils are
on old beach ridges and have slopes of 2 to 30 percent. Soils of the Huerhuero series consist
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Avenida Encinas Extension - Biological Resources Report & Impact Analysis I FIGURE
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I I Avenida Encinas Extension - Biological Resources Report & Impact Analysis FIGURE
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Avenida Encinas Extension Biology Report
of moderately well drained barns that have a clay subsoil. They have slopes of 2-30 percent.
4.0 RESULTS
4.1 Botany - Plant Communities and Floral Diversity
Based on species composition and general physiognomy, three plant communities/habitat types
were identified within the proposed alignment: ruderal/disturbed, disturbed coastal sage scrub,
and artificial wetland. In addition, areas that support existing pavement or structures were
mapped as developed land. The existing plant communities are described below and their
distribution within the alignment is presented in the accompanying vegetation maps (see map
pocket).
4.1.1 Ruderal/Disturbed Habitat
Where native vegetation has been degraded or eliminated by grazing, agriculture, fire, or other
disturbance, the land often reverts to ruderal or weedy habitat. In these situations non-native
grasses and introduced weeds dominate, and there are few or no early successional elements of
the former community.
Within the alignment, ruderal/disturbed habitat occurs where the land formerly supported
agriculture and currently supports dirt roads and weedy roadside vegetation. This includes most
of the alignment that lies between the two paved ends of Avenida Encinas. This area is
dominated by several species of introduced weeds, including black mustard (Brassica nigra), red
brome (Bromus rubens), common barley (Hordeum vulgare), slender wild oat (Avena barbata),
common fiddleneck (Amsinckia intermedia), poison hemlock (Conium maculatum), horseweed
(Conyza canadensis), Australian saltbush (Atriplex semibaccatã), and curly dock (Rumex
crispus).
4.1.2 Disturbed Costal Sage Scrub
Coastal sage scrub is a coastal plant community composed of a variety of soft, low, aromatic
shrubs, characteristically dominated by drought-deciduous species such as California sagebrush
(Artemisia calfornica), flat-top buckwheat (Eriogonum fasciculatum), and sages (Salvia spp.),
with scattered evergreen shrubs, including lemonadeberry (Rhus integnfolia), laurel sumac
(Malosma laurina), and toyon (Heteromeles arbutifolia). It typically. develops on south-facing
slopes and other xeric situations.
In the northern portion of the alignment, existing Avenida Encinas is bordered to the west by
a mosaic of highly disturbed coastal sage scrub and escaped ornamental plantings. The patches
of sage scrub support California sagebrush, flat-top buckwheat, deerweed (Lotus scoparius), and
California encelia (Encelia californica), with scattered individuals of mule fat (Bacchans
Avenida Encinas Extension Biology Report
salicifolia), box-thorn (Lycium calfomicum), lemonadeberry, bladder-pod (Cleome .isomeris),
coastal prickly-pear (Opuntia littoralis), and shadscale (Atriplex canescens). Between and within
the patches of native vegetation are patches of hottentot-fig (Carpobrotus edulis), ice plant
(Mesembyanthemum crystallanum), and tocalote (Centaurea melitensis), and individuals of
myoporum (Myoporum laetum). Although the habitat quality of coastal sage scrub on-site is
low, owing to its isolation from similar habitat and its small patch size, it still supports a
remarkable variety of native plant species.
4.1.3 Artificial Wetland
At the southern end of the proposed Avenida Encinas alignment, near the Volvo dealership,
there is a small artificial wetland. This habitat patch is dominated by cattail (2),pha sp.), with
several clumps of pampas grass (Cortaderia sp.), a small patch of spike-rush (Eleocharis sp.),
carpets of scarlet pimpernel (Anagallis arvensis), and a single moderately large willow tree
(Salix lasiolepis). The hydrophytic (wetland) vegetation present probably is supported and
maintained by run-off from the road and a leaky irrigation system used to water the flower fields
to the immediate northeast. It is likely that the decreased use of irrigation in the surrounding
fields, as a consequence of letting the field lie fallow, will result in a concomitant decline in the
artificial wetland. Currently, the wetland occupies approximately 400 ft' or slightly less that
0.01 acre.
4.1.4 Developed Land
The term "developed land" as used herein refers to paved roads, structures, or areas of high use
in which the recovery of vegetation is inhibited. Existing paved portions of Avenida Encinas
represent typical developed land within the alignment.
4.1.5 Floral Diversity
A total of 71 species of vascular plants - 30 native species (42 percent) and 41 non-native (58
percent) - was recorded from the site (Appendix A). The flora of the site is moderately
depauperate and weedy as a consequence of its disturbed nature. However, the small patches
of disturbed coastal sage scrub support a variety of native shrubs, some of which have a limited
occurrence in coastal San Diego County, i.e., box-thorn (Lycium caljfornicum), California
adolphia (Adoiphia calfornica), bladder-pod (Cleome isomeris), and scale-broom (Lepidospartum
squatnatum).
4.2 Zoology - Wildlife Diversity
4.2.1 Birds-
Nine species of birds were observed during the surveys either within or adjacent to the proposed
7
Avenida Encinas Extension Biology Report
alignment: unidentified hawk (Accipiter sp.), American kestrel (Falco sparverius), killdeer (Charadrius voc(ferus), mourning dove (Zenaida macroura ), Anna's hummingbird (Calypte anna), rough-winged swallow (Stelgi4opteryx ruficollis), house finch (Carpodacus mexicanus), common raven (Corvus corax), and northern mockingbird (Mimuspolyglottos). All are common birds throughout most of southern California, frequently associated with disturbed or urban
habitats. The potential for sensitive birds within the proposed alignment is extremely low.
4.2.2 Reptiles and Amphibians
Reptiles observed on-site include side-blotched lizard (Uta stansburiana) and Great Basin fence lizard (Sceloporus occidentalis). Other reptiles common in the area and likely to occur on-site
include southern alligator, lizard (Gerrhonotus multicarinatus webbiO, western skink (Eumeces skiltonianus), and gopher snake (Pituophis melanoleucus). No amphibians were observed within
the alignment. The potential for the occurrence of sensitive reptiles and amphibians within the
proposed alignment is low.
4.2.3 Mammals
Three species of mammals were recorded from the site. The most frequently observed species
are cottontail rabbit (Sylvilagus sp.) and California ground squirrel (Spermophilus beecheyl).
The presence of diagnostic sign of Botta's pocket gopher (Thomomys bottae) indicates that this
species is active within the alignment as well. No sensitive mammals are likely to be present
within the proposed alignment.
4.2.4 Invertebrates
Butterflies observed on-site include anise swallowtail (Papilio zelicaon), cabbage butterfly (Pieris
rapae), checkered white (Pontiaprotodice), Virginia lady (Vanessa virginiensis), west coast lady
(Vanessa annabella), marine blue (Leptotes marina), pygmy blue (Brephidium exile), and
common harstreak (Strymon melinus). Sandy areas near the termination of the existing northern
portion of Avenida Encinas supported a variety of insects typically associated with sandy soils,
including wasps of the genus Bembix, several species of bee flies (Bombyliidae), and antlions
(Myrmeleonidae). The potential for sensitive invertebrates within the alignment is low.
4.3 Sensitive Biological Resources
The following resources are discussed in this section: (1) plant and animal species present in
the project vicinity that are given special recognition by federal, state, or local conservation
agencies and organizations owing to declining, limited, or threatened populations, that are the
results, in most cases, of habitat reduction; and (2) habitat areas that are unique, are of relatively
limited distribution, or are of particular value to wildlife. Sources used for determination of
sensitive biological resources are as follows: wildlife . -- U.S. Fish and Wildlife Service
8
Avenida Encinas Extension Biology Report
(USFWS 1989, 1991), California Natural Diversity Data Base (CNDDB), California Department
of Fish and Game (CDFG 1980, 1986), Remsen (1978), Everett (1979), McGurty (1980), and
Murphy (1990); plants -- USFWS (1990), CDFG (1987), CNDDB, and Smith and Berg (1988);
and habitats -- CNDDB and Hix (1990).
4.3.1 Sensitive Plant Species
One plant species listed as endangered by the USFWS and CDFG was observed immediately
south of the proposed alignment - San Diego button-celery (Eryngium aristulatum var. parishii). One species listed as locally sensitive by the CNPS (Smith and Berg 1988) was observed within
the alignment - California adoiphia (Adoiphia californica). These species are discussed below; the listing authorities and explanation of listing categories are presented in Appendix C.
E,yn glum aristulatum var. parishii - San Diego button-celery
USFWS: Endangered
CDFG: Endangered .
CNPS: List 1B, 1-3-2
San Diego button-celery is a prostrate or decumbent biennial or perennial species that occurs in
or near vernal pools in Riverside and San Diego counties and in northern Baja California,
Mexico. It blooms from March through July. In San Diego County it has been recorded from
Camp Pendleton, San Marcos, Miramar Naval Air Station, Clairemont Mesa, College Grove,
Carlsbad, and Otay Mesa. The high sensitivity rating combined with the limited habitat
occupied by this species make it a vulnerable and important resource.
This species is abundant along a swale approximately 60 feet east of the railroad tracks outside
of the proposed road alignment. No individuals were observed within the proposed Avenida
Encinas alignment.
Adolphia californica - California adolphia
USFWS: None
CDFG: None
CNPS: List 2, 1-2-1
California adoiphia is a moderate-sized (0.5-1.0 m) profusely branched, rigid, spinescent shrub,
ranging from western San Diego County, California, south into adjacent northwestern Baja
California, Mexico (Wiggins 1980). It generally occurs on clay soils and on dry south-facing
slopes and washes in chaparral and coastal sage scrub communities below 300 m (965 ft) elevation. It blooms in late winter to spring (December-May). In San Diego County it has been
reported from Morro Hill, Cerro de Calavera, Agua Hedionda, Rancho Santa Fe, Mount
Soledad, Bernardo, Chollas Valley, Barrett Junction, and Proctor Valley (Beauchamp 1986).
Avenida Encinas Extension Biology Report
This species is threatened by urbanization, which has reduced considerably its former range
(Smith and Berg 1988).
A small patch of four or five individuals occurs within the alignment on a narrow ridge
immediately west of the northern portion of existing Avenida Encinas.
Potentially Occurring Sensitive Plant Species
Sensitive plant species reported from the immediate vicinity but not observed within or adjacent
to the alignment include Orcutt's brodiaea (Brodiaea orcuttii), little mouse-tail (Myosurus
minirnus var. apus), San Diego navarretia (Naverretia fossalis), and California Orcutt's grass
(Orcutria cal(forniia). All of these are vernal pool species that are found just south and west
of the site on the North County Transit District's proposed Poinsettia Lane station site. These
species are described below; the listing authorities and explanation of listing categories are
presented in Appendix C.
Brodiaea orcuttii - Orcutt's brodiaea
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List 1B, 1-3-2
Orcutt's brodiaea is a herbaceous, spring-blooming (April-July) perennial that grows from a
corm. It is found only in San Diego County, the Santa Rosa Plateau in Riverside County
(Lathrop and Thorne 1985), and northern Baja California, Mexico (Wiggins 1980). It occurs
in association with vernal pools, streams, and seeps. In San Diego County, the species is
encountered infrequently in coastal and foothill regions below 1500 m (4,827 feet) elevation.
Reported localities include the Santa Margarita Mountains, San Marcos, Poway, Henshaw. Dam,
Santa Ysabel, Cuyamaca Mountains, Miramar Naval Air Station, Ramona, Buschalaugh Canyon,
Japatual Valley, Woodwardia Canyon, Cedar Canyon, Otay Mountain, Tecate Mountain and
lower Otay Reservoir (Beauchamp 1986).
Although this species is present approximately 0.2 mile southwest of the site in a swale east of
the railroad tracks, it is not present within or adjacent to the proposed Avenida Encinas
alignment.
Myosurus minimus var. apus - little mousetail
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List 3, 2-3-2
Little mousetail is a small, tufted, spring-blooming (February-April) annual which occurs in
10
Avenida Encinas Extension Biology Report
vernal pools and alkaline marshes in Riverside, San Bernardino, and San Diego Counties
,
a
s
well as Baja California (Munz 1974, Smith and Berg 1988). This species is threatened by t
h
e
loss and degradation of vernal pool habitat. In San Diego County, this species has been repo
r
t
e
d
from vernal pools in National City, Proctor Valley, Otay Mesa (Beauchamp 1986), and Cam
p
Pendleton (J. Brown, personal observation). It is seldom encountered and is one of th
e
r
a
r
e
s
t
vernal pool taxa in San Diego County. Loss of habitat for this plant constitutes a serious
t
h
r
e
a
t
to its survival. It is therefore important to preserve extant populations and potenti
a
l
h
a
b
i
t
a
t
where this plant has been known to occur.
Several individuals of this species were reported by DUDEK (1993) about 0.2 mile southw
e
s
t
of the site in a swale approximately 60 feet east of the railroad tracks. However, it is
n
o
t
present within or adjacent to the proposed Avenida Encinas alignment.
Navarretia fossalis - San Diego navarretia
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List 1B, 2-3-2
This diminutive, white-flowered annual occurs in western Riverside and southwestern San
D
i
e
g
o
Counties, as well as in northwestern Baja California. It generally occurs in vernal po
o
l
s
o
r
roadside depressions below 450 m (1,476 feet) elevation. Historically, N. fossalis occurred in relatively few of the San Diego County vernal pools. Overall, the primary threats to this
s
p
e
c
i
e
s
are loss of habitat due to agriculture and urbanization.
Several clumps of San Diego navarretia were reported by DUDEK (1993) about 0.1 m
i
l
e
southwest of the site in a swale that parallels the railroad tracks. It is not present
w
i
t
h
i
n
o
r
adjacent to the proposed Avenida Encinas alignment.
Orcuttia californica - California Orcutt's grass
USFWS: Candidate (Category 1)
CDFG: Endangered
CNPS: 1B, 273-2
California Orcutt's grass is a low annual with short leaf blades. It is a rare species restri
c
t
e
d
to vernal pools on coastal mesas below about 200 m. In San Diego County, it has been record
e
d
from Miramar Naval Air. Station, south of San Clemente Canyon, and Otay Mesa (Beauchamp 1986). According to Smith and Berg (1988), California Orcutt's grass is seriously threate
n
e
d
by agriculture and overgrazing.
California Orcutt's grass is abundant in a depression approximately 60 feet east of the r
a
i
l
r
o
a
d
tracks just north of the Poinsettia Lane overcrossing. It is. not present within or adjace
n
t
t
o
t
h
e
11
Avenida Encinas Extension Biology Report
proposed Avenida Encinas alignment.
4.3.2 Sensitive Wildlife Species
No animal species recognized as threatened, endangered, or rare by USFWS or CDFG were
observed within or adjacent to the proposed alignment. Based on general information regarding
wildlife distributions in the area, the alignment has a low potential to support any sensitive
wildlife species.
4.3.3 Sensitive Habitats
Sensitive habitats are those that are considered rare within the region, support sensitive plant
and/or wildlife species, or function as corridors for wildlife movement. The only habitat types
found within the proposed alignment that could be considered sensitive are the small artificial
wetland and the disturbed coastal sage scrub. Vernal pool, recognized as a highly sensitive
habitat type, is present adjacent to the southwesternmost corner of the proposed alignment.
4.3.4 Wildlife Corridors and Habitat Linkages
Wildlife corridors are linear features that connect large patches of natural open space and
provide avenues for the immigration and emigration of large 2nimls. Wildlife corridors
contribute to population viability in several ways: (1) they assures the continual exchange of
genes between populations which helps maintain genetic diversity; (2) they provides access to
adjacent habitat areas representing additionil territory for foraging and mating; and (3) they
allow for a greater carrying capacity.
In order to evaluate the importance of the Avenida Encinas Extension in the context of wildlife
movement, it is important to identify the animal species that potentially use the area. The
primary "target" species typically identified for the maintenance of wildlife corridors are larger
mammals, including bobcat, mountain lion, and mule deer. All of these species have been
excluded from the proposed development area (i.e., Avenida Encinas) for many years.
Habitat linkages are patches of native habitat that function to join two larger patches of habitat.
They serve as connections between habitat patches and help reduce the adverse affects of habitat
fragmentation. Although individual animals may not move through a habitat linkage, the linkage
does represent a potential route for gene flow and long-term dispersal. Habitat linkages may
serve as both habitat and avenues of gene flow for small animals such as reptiles and
amphibians.
The City of Carlsbad currently is in the process of preparing implementation plans for the
Carlsbad Habitat Management Plan (HMP). The HMP is a multiple species planning effort
12
Avenida Encinas Extension Biology Report
intended to maintain biological diversity in the City of Carlsbad. The HMP has identified no
important habitat linkages or wildlife corridors in the vicinity of the proposed alignment.
5.0 JMPACTSOF A PROPOSED ROADWAY
This Section addresses potential impacts to biological resources that would result from
implementation of the proposed Avenida Encinas extension, and provides analyses of significance
for each potential impact. Direct impacts were quantified by overlaying the proposed alignment,
as provided by the City of Carlsbad, on the biological resources map of the site. For purposes
of this impact analysis, the proposed area of construction extends only from the drainage that
traverses the middle of the Avenida Encinas Wastewater Treatment Facility, south to the Volvo
Dealership (i.e., primarily the area between the two ends of the existing roadways). It is
assumed that all resources within the alignment would be directly impacted.
Indirect impacts usually cannot be measured directly and may include habitat fragmentation and
isolation, displacement of wildlife, interruption of wildlife corridors, and edge effects associated
with development (e.g., noise and light impacts, introduction of urban meso-predators, invasion
of non-native plants).
5.1 ExplanatiOn of Findings of Significance
Impacts to native habitats,. sensitive plants, and sensitive wildlife species must be quantified and
analyzed to determine whether-such impacts are significant. According to the California
Environmental Quality Act (CEQA) guidelines, impacts associated with a proposed development
project are considered significant if implementation of the project will:
1)' Substantially affect a rare or endangered species of plant or animal or the habitat
of that species.
. Interfere substantially with the movement of any resident or migratory fish or
wildlife species.
Substantially diminish habitat for fish, wildlife, or plants.
The evaluation of whether or not an impact to a particular biological resource is significant must
consider both the resource itself and the role of that resource in a regional context. Significant
impacts re those that contribute to, or result in, permanent loss of an important, resource, such
as a population of a rare plant or animal. Impacts may be important locally because they result
in an adverse alteration of existing site conditions, but considered not significant because they
do not contribute substantially to the permanent loss of that resource regionally. The severity
of an impact is the primary determinant of whether or not that impact can be mitigated. to a level
13
Avenida Encinas Extension Biology Report
that is below significant.
5.2 Assessment of Impacts to Sensitive Biological Resources
The proposed extension of Avenida Encinas would result in the direct loss of only one sensitive
habitat type: 0.01 acre of low quality wetland habitat. Because of the artificial nature of this
habitat, its small size, and its isolation, this impact is considered not significant.
6.0 MITIGATION MEASURES
Because impacts to biological resources are considered not significant, no mitigation measures
are required. However, the potential exists for inadvertent indirect impacts to vernal pool
habitat and the single individual of San Diego button-celery near the alignment. Hence, prior
to initiation of construction activities, adjacent. vernal pool habitat should be marked clearly by
red flagging, and construction personnel should be cautioned to avoid these highly sensitive
resources.
7.0
This report was prepared. by DUDEK biologist John W. Brown, Ph.D. Brock A. Ortega
provided field assistance. Graphics were provided by Martie A. Clemons; Tonette S. Foster
provided word processing assistance.
8.0 LITERATURE CITED
American Ornithologists' Union. 1983. The Check-list of North American Birds, 6th edition.
Allen Press, Lawrence, Kansas.
American Ornithologists' Union. 1989. Thirty-seventh Supplement to the American
Ornithologists' Union Check-List of North American Birds. The Auk 106:532-538.
Beauchamp, R. M. 1986. A flora of San Diego County, California. Sweetwater Press,
National City, California. 241 pp.
Bond, S. I. 1977. An annotated list of the mammals of San Diego County, California.
Trans. San Diego Soc. Nat. Hist. 18: 229-248.
Bowman, R. H. 1973. Soil Survey, San Diego Area, California, Part 1. United States
Department of the Agriculture. 104 pp. + appendices.
California Department of Fish and Game (CDFG). 1980. At the Crossroads: A Report on the
14
- Avenida Encinas Extension Biology Report
Status of California's Endangered and Rare Fish and Wildlife. State of Califoi
Resources Agency, Sacramento. California.
California Department of Fish and Game (CDFG). 1986. Endangered, Rare, and Threate:
Animals of California. State of California Resources Agency, Sacramento, Califon
er. California Department of Fish and Game (CDFG). 1987. Designated Endangered or P
Plants. Summary list from Section 1904 Fish and Game Code (Native Plant Proteci
Act). State of California Resources Agency, Sacramento, California.
Dudek & Associates, Inc. (DUDEK). 1993. Biological Resources Report and Vernal
-. Protection Plan for the Oceanside-San Diego Commuter Rail Project, Poinsettia
Station. Prepared for Helene Kornblatt.
ab
Emmel, T. C. and J. F. Emmel. 1973. The butterflies of Southern California. Natural Hist
- Museum of Los Angeles County, Science Series 26:1-148.
lit Everett, W. T. 1979. Sensitive, threatened and declining bird species of San Diego Cow
San Diego Audubon Society Sketches 29:2-3.
Hickman, J. C. 1993. The Jepson Manual. University of California Press, Berkeley. 1400
Hix, A. B. 1990. Sensitivity of San Diego's Biological Resources: An Informational Rep
City of San Diego Planning Department, Development and Environmental Planx
Division. 29 pp. + attachments.
it( Holland, R. F. 1986. Preliminary descriptions of the terrestrial natural communitie
California. Nongame-Heritage Program, California Department of Fish and Game.
PP.
I itt . •
Jones, J. K., Jr., D. C. Carter, H. H. Genoways, R. S. Hoffman, and D. W. Rice. P
Revised Checklist of North American Mammals North of Mexico. Occasional Pa
Tcr of the Museum of Texas Tech University, no. 80..
Lathrop, E. W. and R. F. Thorne. 1985. A flora of the Santa Rosa Plateau, Sout
California. Southern California Botanists, Special PublicatiónNo. 1. 39 pp.
McGurty, B. M. 1980. Survey and status of endangered and threatened species of re
natively occurring in San Diego, California. San Diego Herpetological Society.
Muàz, P.. 1974. A flora of Southern California. University of California Press, Berk'
15
Avenida Encinas Extension Biology Report
California. 1086 pp.
Murphy, D. D. 1990. A report on the California butterflies listed as candidates for endangered
status by the United States Fish and Wildlife Service. Draft Report for California
Department of Fish and Game, Contract No. C-1755. 60 pp.
Remsen, J. V. 1978. Bird species of special concern in California: An annotated list of
declining or vulnerable bird species. Administrative Report No.. 78-1. Nongame
Wildlife Investigations, Wildlife Management Branch, California Department of Fish and
Game.
Smith, J. P., Jr., and K. Berg. 1988. California Native Plant Society's Inventory, of Rare and
Endangered Vascular Plants of California. Special Publication No. 1 (4th Edition),
California Native Plant Society, Sacramento, California. 168 pp.
Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Muffin
Co., Boston, Mass.
United States Fish and Wildlife Service (USFWS). 1989. Federal Register, Part 4, Endangered
and Threatened Wildlife and Plants; Animal Notice of Review. 50 CFR Part 17.
Department of the Interior.
United States Fish and Wildlife Service (USFWS). 1990. Federal Register, Part 4, Endangered
and Threatened Wildlife and Plants; Review of Plant Taxa for Listing as Endangered or
Threatened Species, Notice of Review. 50 CFR Part 17. Department of the Interior.
United States Fish and Wildlife Service (USFWS). 1991. Federal Register, Part 8, Endangered
and Threatened Wildlife and Plants; Animal Candidate Review for Listing as Endangered
or Threatened Species, Proposed Rule. 50 CFR Part 17. Department of the Interior.
Unitt, P. A. 1984. Birds of San Diego County. Memoir 13, San Diego Society of Natural
History. 287 pp.
Wiggins, I. L. 1980. A flora of Baja California. Stanford University Press. 1025 pp.
16
APPENDICES
17.
APPENDIX A
VASCULAR PLANT SPECIES OBSERVED
ON THE PROJECT SITE
ANGIOSPERMAE (DICOTYLEDONES)
AIZOACEAE - CARPETWEED FAMILY
* Carpobrotus edulis - hottentot-fig
* Mesembiyantizemum nodflorum - little ice plant
* Meseinbyanthemum crystallanum - crystal ice plant
ANACARDIACEAE - SUMAC FAMILY
Rhus integrzfolia - lemonadeberry
* Schinus terebin:hfolius. - Brazilian pepper-tree
AMARANTHACEAE - AMARANTH FAMILY
* Amaränthus albus - white tumbleweed
APIACEAE - CARROT FAMILY
* Conium maculatum - poison hemlock
Eryngium aristulatum var. parishii - San Diego button-celery
* Foeniculum vulgare - sweet fennel
ASTERACEAE --SUNFLOWER FAMILY
Artemisia californica - coastal sagebrush
Baccharis pilularis - coyotebush
Baccharis salicfolia - mule fat
Centaurea melitensis - tocalote
* Chrysanthemum coronanum - garland chrysanthemum
Conyza canadensis - horseweed
Encelia californica - bush sunflower
Gnaphalium sp. - everlasting
Hazardia squarrosus - saw-toothed goldenbush
Hemizonia fasciculata - fascicled tarweed
Heterotheca grañdjflora - telegraph weed
Isocoma veneta - coastal goldenbush
* Lactuca serriola - prickly lettuce
Lepidospartum squamaium -. scale-broom
* Sonchus asper - prickly sow-thistle
Stephanomeria virgata - wreathplant
18
APPENDIX A (continued)
Xanthium strumarium - cockle-bur
BORAGINACEE - BORAGE FAMILY
Amsinckia intermedia - yellow fiddleneck
Heliorropium curvassivicum - wild heliotrope
BRASSICACEAE - MUSTARD FAMILY
* Brassica nigra - black mustard
* Coronopus didymus lesser water-cress
Raphanus sativus - wild radish
* Si.symbrium irio - London-rocket
CACTACEAE - CACTUS FAMILY
Opuntia littoralis -coast prickly-pear
CAPPERACEAE - CAPPER FAMILY
Cleome isomeris - bladder-pod •
CARYOPHYLLACEAE - PINK FAMILY
* Spergula arvensis - corn spurry
CHENOPODIACEAE. - GOOSEFOOT FAMILY
* Atriplex sernibaccata - Australian saitbush
Atriplex canescens - shadscale
*• Chenopodium sp. goosefoot
Salsola australis - Russian-thistle
FABACEAE -PEA FAMILY
* Acacia sp. - acacia
Lotus scoparius - deerweed
* Melilotus albus - white sweet-clover
GERANIACEAE - GERANIUM FAMILY
* Erodium cicutdrium - red-stemmed filaree
LYTHRACEAE - LOOSESTRIFE FAMILY
Lythrum hyssopifolia - grass poly
MALVACEAE -MALLOW FAMILY
*. Malva par'4flora - cheese weed
11
19
APPENDIX A (continued)
MYOPORACEAE - MYOPORUM FAMILY
* Myoporum laetüm - myoporurn -
PLUMBAG1NACEAE - LEADWORT FAMILY
* Limonium sp. rosemary
POLYGONACEAE - BUCKWHEAT FAMILY
Eriogonum fàsciculatum - flat-top buckwheat
* Rumex crispus - curly dock
PRIMULACEAE - PRIMROSE FAMILY
* Anagallis arvensis - scarlet pimpernel
RHAMNACEAE - BUCKTHORN FAMILY
Adoiphia cal4fornica - California adoiphia
SALICACEAE -MELLOW FAMILY
Salix lasiolepis - arroyo willow
SOLANACEAE - NIGHTSHADE FAMIY
Datura wrightil - jimsonweed
Lycium calfornicum. - box-thorn
* Mcotiana glauca - tree tobacco
* Solanurn elaeagnifolium - silver-leaf horse nettle
Solanum douglasii - Douglas' nightshade
ANGIOSPERMAE (MONOCOTYLEDONES)
LILIACEAE - LILY FAMILY
* Yucca gloriosa - glorious yucca
CYPERACEAE - SEDGE FAMILY
* Cyperus alternifolius - African umbrella-plant
Eleocharis macrostachya - pale spike-rush
POACEAE - GRASS FAMILY
* Avena barbata - slender wild oat
* Bromus diandrus - ripgut grass
* Bromus hordeaceus - soft chess
20
APPENDIX A (continued)
* Bromus madritensis var. rubens - red brome
* Cortderia dioica - pampas grass
* Cynodon dactylon - Bermuda grass
Disticklis spicata - salt grass
* Hordeum sp barley
Lolium perenne - English ryógrass
* Phalaris cananensis - Mediterranean canary grass
* Polypogon monspeliensis - rabbitfoot grass
TYPHACEAE - CATTAIL FAMILY
Typha lat(folia - tall cattail
* signifies introduced (non-native) species
21
APPENDIX B.
WILDLIFE SPECIES OBSERVED OR
DETECTED ON THE PROJECT SITE
TERRESTRIAL VERTEBRATES
BIRDS .
ACCIP1TRJDAE -HAWKS
Accipiter sp.
FALCONIDAE - FALCONS . .. .
Falco sparverius - American kestrel
CHARADRIIDAE - PLOVERS
Charadrius vocferus - killdeer
COLUMBIDAE - PIGEONS & DOVES
Zenaida macroura - mourning dove
TROCHILIDAE HUMMINGBIRDS
Calypte anna - Anna's hummingbird
H1RUDINIDAE - SWALLOWS
Stelgidopteryx ruficollis - rough-winged swallow
CORVIDAE - JAYS & CROWS
Corvus corax - common raven
MIMIDAE - THRASHERS
Mimus polyglottos - northern mockingbird
FRINGILLIDAE - FINCHES
.Carpodacus mexicanus - house finch
MA1'1MALS
LEPORIDAE - HARES & RABBITS
Sylvilagus sp. - cottontail rabbit
22
APPENDIX B (continued)
SCIURIDAE - SQUIRRELS
Sperrnophilus beechyi California ground squirrel
GEOMYIDAE - POCKET GOPHERS
Thomomys bottae - Botta's pocket gopher
REPTILES
IGUANIDAE - IGUANID LIZARDS
Scieroporus occidentalis - Great Basin fence lizard
Uta stansburiana - side-blotched lizard
TERRESTRIAL INVERTEBRATES
HESPERIIDAE - SKIPPERS
Hylephila phyleus - firey skipper
PAPILIONIDAE - SWALLOWTAILS
Papilio zelicaon - anise swallowtail
PIERLDAE - WHITES & SULFURS
Pieris rapae - cabbage butterfly
Pontia protodice - checkered white
LYCAENU)AE - BLUES, COPPERS & HAIRSTREAKS
Stiymon melinus - common hairstreak
Brephidium exile - western pygmy blue
Leptotes marina - marine blue
NYMPHALIDAE - BRUSH-FOOTED BIJTI'ERFLIES
Vanessa virginiensis - Virginia lady
Vanessa annabella - west coast lady
Vanessa cardui painted lady
23
APPENDIX C
SPECIES SENSITIVITY CATEGORIES
Federal (1989)
Endangered. Taxa threatened throughout all or a significant portion of their range.
Threatened. Taxa likely to become endangered in the foreseeable future.
Category 1. Taxa for which the USFWS currently has on file substantial information on
biological vulnerability and threat(s) to support the appropriateness of proposing to list them as
endangered or threatened species.
Cateory 2. Taxa for which information now in possession of the USFWS indicates that
proposing to list them as endangered or threatened is appropriate but for which substantial data
on biological vulnerability and threat(s) are not known or on file to support the immediate
preparation of rules.
Category 3. Taxa that were once considered for listing as endangered or threatened, but are
currently not receiving such consideration. These taxa are included in one of the following three
subcategories.
Subcategory 3A: Taxa presumed to be extinct.
Subcategory 3B: Taxa whose names do not meet the Endangered Species Act's
legal definition of species.
Subcategory 3C: Taxa now considered to be more widespread that originally
thought.
Note: The taxa in Categories 1 and 2 are candidates for, possible addition to the list of
endangered and threatened species. The USFWS encourages their consideration in
environmental planning.
State of California (1990)
Endangered. Taxa which are in serious danger of becoming extinct throughout all, or a
significant portion, of their range. due to one or more causes including loss of habitat, change
in habitat, over exploitation, predation, competition, or disease (Section 2062 of the Fish and
Game Code).
Threatened. Taxa which, although not presently threatened with extinction, are likely to become
endangered species in the foreseeable future (Section 2067 of the Fish and Game Code).
24
APPEND C (continued)
Rare. Taxa which, although not presently threatened with extinction, are present in such small
numbers throughout their range that they may become endangered if the present environment
worsens (Section 1901 of the Fish and Game Code).
Candidate. Taxa which the Fish and Game Commission has formally noticed as being under
review by the Department in addition to the list of threatened and endangered species.
California Native Plant Society (1988)
Lists
lA: Presumed Extinct in California
1B: Rare or Endangered in California and Elsewhere
. Rare or Endangered in CalifOrnia, More Common Elsewhere
Need More Information . .
Plants of Limited Distribution
.
Note: Plants on CNPS list. I meet California Department of Fish and Game Criteria for
Rare or Endangered listing. .
R-E-D code
R (Rarity) . .
Rare, but found in sufficient numbers and distributed widely enough that the potential
for extinction or extirpation is low at this time.
Occurrence confined to several populations or to one extended population.
Occurrence limited to one or a few highly restricted populations, or present in such
small numbers that it is seldom reported. .
E (Endangerment) . . . .
Not endangered .
Endangered in a portion of its range.
Endangered throughout its range
D (Distribution)
More or less .widespread outside of California
Rare outside, California .
Endemic to California
25
PALEONTOLOGICAL RESOURCES REPORT
AND IMPACT ANALYSIS
FOR THE AVENIDA ENCINAS EXTENSION
CITY OF CARLSBAD
SAN DIEGO COUNTY, CALIFORNIA
Prepared for:
CITY OF CARLSBAD
2075 Las Palmas Drive
Carlsbad, California 92009-1576
Contact: Pat Entezari
(619) 438-1161 ext. 4385
Prepared by:
PALEOSERVICES
P.O.* Box 33671
San Diego, California 92163
-J
Contact: Thomas A.Demere • •
(619) 738-9905 •
• •
8 Octobet
Dr. John W. Brown
Dudek & Associates, Inc.
605 Third Street
Encinitas, CA 92024
PALE 0 V-4E
.
RVICES
RE: Final Report on Paleontological Resources;
Avenida Encinas, City of Carlsbad
Dear John:
This letter report represents a summary of my findings
concerning the specific paleontological resource potential
of the proposed Avenida Encinas Extension project, City of
Carlsbad, San Diego County, California.
As defined here, paleontological resources (i.e.,
fossils) are the remains and/or traces of prehistoric plant
and animal life exclusive of man. Fossil remains such as
bones, teeth, shells, and leaves are found in the geologic
deposits (rock formations) within which they were originally ,
buried. For the purposes of this report, paleontological
resources can be thought of as including not only the actual
fossil remains but also the collecting localities, and the
geologic formations containing those localities.
Paleontological resources represent a limited,
nonrenewable, and sensitive scientific and educational
resource. In California, impacts to such resources are
addressed under regulations of the California Environmental
Quality Act.
Methods
Determination of the palebntological resource potential
of the proposed project is based upon a review of
unpublished geological reports (Wilson 1972), published
geological reports (Eisenberg 1985), published
paleontological reports (Golz 1976; Golz and.Lillegraven
1977; Deméré 1980), and museum.paleontological locality
records (San Diego Natural History Museum-Department of
Paleontology). A walkover survey of the proposed alignment
was carried out tofield check the results of the literature
and record reviews.
Existing Conditions
Introduction- The proposed extension of Avenida Encinas
between Palomar Airport Road on the north and the Garton
Volvo Dealership on the south, involves approximately 5400
feet of right-of-way (ROW) running roughly parallel tàthe
A.T. & S.F. Railroad track. Elevations range from about 30
feet above sea level near the Water Pollution Control
Facility to 78 feet at the intersection of Palomar Airport
Road and Avenida Encinas. The northern 3600 feet of the ROW
is currently paved, while the remaining portion of the ROW
crosses agricultural land. Several isolated roadcut
outcrops occur along the western border of the ROW between
the Prudential Securities Building and the Water Pollution
Control Facility. Good exposures of bedrock also occur in
artificial slopes for the railroad ROW.
General Geology- As summarized on the Encinitas, CA,
7.5' USGS quadrangle geologic maps of Wilson (1985) and
Eisenberg (1985) the general geology of the ROW consistèof
a "layer cake" sequence of terrestrial and nearshore marine
sedimentary rock formations.. From-oldest to youngest this
geologic series consists of middle Eocene-aged.
(approximately 40-45 million years old) sedimentary rocks of
the Santiago Formation (called Delmar/Friars formation by
Eisenberg, 1985) and unnamed late Pleistocene-aged
(approximately 120,000 years old) marine terrace deposits
(Figure 1). • •. •
The Santiago Formation along the ROW is not exposed at
the surface, but does occur in low outcrops located about
300 feet west of the ROW, near Success Street. The Santiago
Formation here consists of very light brown, moderately well
sorted, medium-grained arkosic sandstones and olive-green,
poorly sorted, coarse-grained, gravelly sandstones. The
Unnamed
upper Pleistocene . . : : : ; •
terrace deposits -. .
. I • • •
I • p . S •
I S S
... S
I -
-. - -I • - - -
Santiago
Formation : •
-
I
• •5%
- • - ' . S
I • S I
FIGURE -1 - Generalized stratigraphic section along the
Avenida Encinas Extension ROW. See text for a description
of the unnamed upper Pleistocene marine terrace deposits and
the Santiago Formation.
Santiago Formation was deposited in a coastal estuary and
river delta setting.
The unnamed upper Pleistocene terrace deposits directly
overlie the Santiago Formation and consist of brown and
gray, well sorted, medium-grained, massive and faintly
laminated sandstones and dark brown and reddish brown,
massive, sandy mudstones, with local concentrations of
nodular caliche. This rock unit was deposited on a wave-cut
platform (sea floor) that was cut into the sandstones of the
Santiago Formation during a late Pleistocene high sea stand.
The basal sandstone portion of this rock unit represents
nearshore marine deposits (i.e., beach and surf zone), while
the overlying massive mudstones represent ancient soils
(i.e., paleosols).
The present-day contact between the Santiago Formation
and the overlying Pleistocene terrace deposits occurs at
about 20 feet above sea level (visible on the slopes south
of Success Street). The erosion surface (i.e., wave-cut
platform) separating these two rock units dips (i.e., tilts)
gently to the west and results in an eastward rise in this
contact.
The only sedimentary rocks physically exposed along the
ROW are the sandstones and paleosols of the Pleistocene
terrace deposits. However, the Santiago Formation does
occur along the ROW, but is confined to the subsurface-
(below elevations of approximately 20 feet).
The northernmost 500 feet of the ROW are underlain by
artificial fill materials imported into the area to
construct the elevated intersection of Palomar Airport Road
and Avenida Encinas,
Paleontology- Museum locality records do not document
any known fossil localities along the proposed ROW and none
were discovered during the field survey. It is important to
point out that many fossil sites presently on record in San
Diego County have been discovered only during residential
development activities or during highway and freeway
construction projects. This close correlation between
fossil sites and new construction is due to the fact that
surface weathering quickly destroys most fossil materials,
and it is not until fresh unweathered exposures are created
by grading that well preserved fossils are often recovered.
Carlsbad has numerous examples of construction-related
fosSil discoveries beginning with the discoveries at Laguna
Riviera back in the 1970's and continuing into the.1980's
and 1990's with discoveries at the Carlsbad Research Center,
the Airport Business Center, and the College Boulevard
Extension.
Based upon the published literature and upon recent
fossil discoveries in the Carlsbad area, the Santiago
Formation is considered to be potentially fossiliferous
almost everywhere it occurs. The fossils known from this
formation include marine and estuarine invertebrates (clams,
snails, sea urchins) as well as terrestrial vertebrates
(turtles, lizards, birds, rodents, carnivores, tapirs,
brontotheres, archaic rhinoceros, and primitive deer-like
and camel-like mammals)(Golz 1976; Golz and Lillegraven
1977). This assemblage of fossil organisms represents one
of the richest sources of Eocene paleontological materials
in the western United States. The Santiago Formation has a
high potential for yielding significant paleontological
resources. . .
The unnamed late Pleistocene terrace deposits have
produced fossils from only a few areas in northern San Diego.
County. Fossils collected from these deposits are generally
shells of marine invertebrates (clams and snails)(Demèrè
1980). Reports of vertebrate fossils are rare and include
the discovery of a mastodon tooth at Carlsbad (noted in the
older records of the San Diego Natural History Museum, but
unfortunately now lost), and discovery of ground sloth limb
bones at Fairbanks Ranch. The unnamed late Pleistocene
terrace deposits have a moderate potential for yielding
significant paleontological resources.
Knowing the past fossil potential of a particular
geological "layer" in one area is a reliable method for
determining the resource potential of that same "layer" in
other, perhaps unexDlored, areas.
Ej
Imoact Analysis
Impacts to significant paleontological resources occur
when earth work activities, such as mass excavation
projects, cut into the geological deposits (formations)
within which fossils are buried. These impacts are inthe
form of physical destruction of fossil remafns. -Since
fossils are the remains of prehistoric animal and plant life
they are considered to be nonrenewable. Such impacts are
significant and, under CEQA guidelines, require mitigation.
As already discussed, the proposed ROW is underlain at
depth by geologic deposits (i.e., the Santiago Formation)
with a high potential for producing significant
paleontological resources (fossils), while closer to the
surface the ROW is underlain by deposits with a moderate
resource potential.
Plans for the initial phase of construction of the
Avenida Encinas extension only propose earthwork activity
along-the portion of the ROW between the Water Pollution
Control Facility and the Garton Volvo Dealership. In
addition, the earthwork planned for this segment will
involve only very shallow excavations (three feet at most).
Given •these two conditions (short ROW Segment and shallow
excavations) it is suggested that the proposed construction
activities will not result in significant impacts to
sensitive paleontological resources.
Mitiaation Measures
G.iven the lack of significant impacts as discussed
above, there will be no need for mitigation. This
determination only applies to the initial phase of
construction. As future phases of road work along the
remainder of the ROW come on-line, the nature of the
proposed impacts on paleontological resources will need to
be evaluated. • • •
In summary, the project site possesses a potential fr
producing sensitive paleontological resources. However, a5
presently-proposed the initial construction activities will
not result insignificant impacts-to these resources.
Therefore there is no need for mitigation. In the event
that, construction plans change or. additional phases come on-
line it will, then be' necessary to re-evaluate the nature of
impacts.' Please feel free to contact me if you have any
questions concerning my findings.
Sincerely yours,
-7G A'
Thomas A. Deméré
PaleoServices, Inc
References
Demèrè, T. A. 1980. A late Pleistocene molluscan fauna from
San Dieguito Valley, San Diego County, California. San
Diego Society of Natural History, Transactions.
19(15):217-226.
Eisenberg, L. I. 1985. Pleistocene faults and marine -
terraces, northern San Diego County. pp.87-91. in P. L.
Abbott (ed.). On the Manner of Deposition of the Eocene
Strata in Northern San Diego Couhty. San Diego
Association of Geologists. Field Trip Guidebook.
Golz, D. J. 1976. Eocene Artiodatyla of southern
California. Natural History Museum of Los Angeles
County Science Bulletin 26:1-85.
Golz, D. J. and J. A. Lillegraven. 1977. Summary of known
occurrences of terrestrial vertebrates from Eocene
strata of southern California. Contributions to
Geology University of Wyoming 15(1):43-65.
Wilson, K. L. 1972. Eocene and related geology of a portion
of the San Luis Rey and Encinitas quadrangles, San
Diego County, California. unpublished Master's thesis,
University of California, Riverside. 135 p.
ARCHAEOLOGICAL RESOURCES REPORT
AND IMPACT ANALYSIS
FOR THE AVENIDA ENCINAS EXTENSION
CITY OF CARLSBAD
SAN DIEGO COUNTY, CALIFORNIA
Prepared for:
CITY OF CARLSBAD
2075 Las Palmas Drive
Carlsbad, California 92009-1576
Contact: Pat Entezari
(619) 438-1161 ext. 4385
Prepared by:
BRIAN F. SMITH AND ASSOCIATES
14678 Ibex Court
San Diego, California 92129
Contact: Brian F. Smith
(619)484-0915
-J
BRIAN F. SMITH AND ASSOCIATES
ARCHAEOLOGICAL AND HISTORICAL CONSULTING
October 15, 1993
John W. Brown, Ph.D.
Dudek & Associates, Inc.
605 Third Street
Encinitas, California 92024
Dear John:
On September 10,1 submitted a letter to you and the City of Carlsbad regarding the archaeological
survey of the Avenida Encinas Extension Project The field reconnaissance and the record
searches were complete at that time, and although the records did not indicate the presence of any
previously discovered sites within the alignment, the reconnaissance resulted in the identification of
a single prehistoric site within the proposed construction corridor. This site, temporarily
designated as Site AE- 1, is characterized by a scatter of marine shell and two lithic artifacts. The
marine shell is not a natural deposit, as it consists exclusively of species used for food by
prehistoric inhabitants of the area, and is not indicative of a naturally-occurring variety of shell
species that might be expected along the shoreline.
Based upon the field interpretation that the shell and lithic artifacts constitute a prehistoric cultural
resource, an investigation of the site.was initiated with the approval of the City of Carlsbad. The
testing was needed to determine the significance of the site and whether the proposed construction
would impact the site. This testing is required by CEQA and the environmental guidelines of the
City of Carlsbad.
The testing program was conducted at the site on October 5 and 6. The testing program included
the mapping and recovery of all surface artifacts, and the excavation of shovel tests (cores) and a
standard test unit to examine the subsurface area of the site. The surface mapping and recovery
procedure resulted in the recovery of just two artifacts, a core and a flake. Shell from the surface
of the site was not collected, because it had been superficially scattered and lacked provenience.
Following the surface mapping, a series of ten shovel tests was excavated. These tests were .
located along four lines extended from the center of the shell scatter where the mapping datum was
established. The lines were set at 00,900, 1800, and 2700. The shovel tests were spaced at ten-foot
intervals. None of the shovel tests produced any artifacts or shell, and no other indications of a
subsurface deposit were observed. Following the shovel test series, a single one-meter-square test
unit was excavated in the densest area of the surface scatter of shell. This unit was excavated to a
depth of 40 centimeters, and all removed soil was sifted through one-eighth-inch mesh screen.
The test unit resulted in the recovery of approximately one gram of shell. Although the shell
quantity was small, the small fragments were present throughout the first three decimeter levels.
No lithic artifacts were recovered from the test unit.
The field study of Site AE-1 resulted in the recordation of a small shell scatter measuring
approximately 40 feet in diameter. The site was previously disturbed by grading, cultivation and
trenching. The site may have been larger at one time, but modern impacts appear to have reduced
the site area. The testing program provided information that indicated that there is no subsurface
14678 IBEX CouRT SAN DIEGO. CALIFORNIA 92129 (619) 484-091S FAx (619)484.0988
Brian F. Smith - October 15, 1993 - Page Two
deposit present. The very small quantity of shell recovered from the test unit was probably
originally part of the surface scatter, but was subsequently buried by modern impacts, such as
disking. The, small quantity of shell recovered does not represent a subsurface deposit, nor does it
suggest the presence of a deposit within the site area.
The information collected during the survey and testing program is sufficient to characterize the
archaeological site as a surface scatter of shell and two lithic artifacts, but no subsurface deposits
were found. The site does not contain any potentially important deposits, nor does the site
represent a source of additional research potential. Therefore, any impacts to the site from the
proposed road improvement project will not be significant or adverse. No mitigation measures are
recommended, and no further studies are needed..
However, I do recommend that an archaeologist monitor the grading of the road. While the testing
of Site AE- 1 did not reveal a significant cultural resource, the potential for the existence of other
sites in the area is high. Because of the close proximity of the project to the coast and the
importance of the coastal zone to the prehistoric inhabitants of the region, the possibility that
resources may be present, perhaps buried, 'cannot be ignored. The archaeological monitoring of
grading projects in the City of Carlsbad is required by the City's guidelines wherever buried or
masked resources may be present.
Please let me know if you have any questions.
Brian F. th
BFS:ks