Chapter 4 Environmental Setting, Impacts, and Mitigation
4.4
BIOLOGICAL RESOURCES
This section describes the existing biological resources in and near areas affected by the project.
Vegetation types and wildlife habitats were characterized on the basis of both records and field
observations. The assessment area is essentially the area shown on Figure 3-1, including both the
proposed eastern and western agricultural areas. Reconnaissance-level field studies were conducted
throughout the assessment area in December 2000, May 2001, and August 2001. Additional focused
surveys for the Mohave ground squirrel were conducted by Philip Leitner on August 14-15, 2001, for the
storage reservoir area, and on September 18, 2001, for the eastern agricultural area. A literature review of
the potential for the desert tortoise to exist in the assessment area was conducted by Alice Karl. Sensitive
plant surveys were conducted for the proposed storage reservoir location on May 5-9, 2003. These survey
reports of the Mohave ground squirrel, desert tortoise, and sensitive plant assessments were used to
develop this section and are included in Appendices I and J. Additional consultation was conducted with
local experts Mike San Miguel, president of the Western Field Ornithologists, and Kimball Garrett,
Ornithology Collections Manager, Natural History Museum of Los Angeles.
4.4.1
Environmental Setting
Methodology
References used in the preparation of this section include information from the following reports and
surveys:
•
Reconnaissance-level and focused field surveys performed in December 2000, May and August 2001,
and in May 2003.
•
Records from the California Natural Diversity Database (CNDDB).49
•
Contacts with resource experts50 and an EAFB staff biologist.51
49
CNDDB, 2001.
50
Garrett pers. comm. 2001; Leitner, pers. comm. 2001.
51
C. Rush, pers. comm. 2000.
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•
Focused habitat assessments for the Mohave ground squirrel52 and sensitive plants53 and a literature
review for the desert tortoise.54
•
Focused special-status plant and wildlife studies recently conducted for the adjacent EAFB and
available online.55
Assessment Area
The LWRP is located 5.5 miles north of the City of Lancaster, California, immediately west of EAFB on
land owned by District No. 14. The project is located in the Mojave Desert region of the California
Floristic Province56 and within the Pacific Flyway. The Pacific Flyway is one of the four major northsouth migration corridors in North America that migratory birds follow during their spring and fall
migrations. For purposes of assessing biological resources, an area of approximately 25 square miles was
evaluated at a reconnaissance level. The assessment area includes currently or historically developed
areas or agricultural areas toward the west, disturbed open space desert encompassing the proposed
storage reservoir area, Piute Ponds, Rosamond Dry Lake, and agricultural areas to the east.
The
assessment area slopes gently (0 to 5 percent) towards Rosamond Dry Lake.
Biotic Habitats within the Assessment Area
Shadscale Scrub
Shadscale scrub (Atriplex confertifolia) dominates the landscape west of Rosamond Dry Lake including
the entire proposed storage reservoir area. This habitat type extends westward toward Nebeker Ranch but
is more disturbed and of lower quality west of Sierra Highway. Though generally more disturbed,
portions of the project assessment area located east of SR-14 support a combination of shadscale and
rabbitbrush (Chrysothamnus nauseosus), with incrementally greater densities of Great Basin sage
(Artemesia tridentata) west of SR-14. Agricultural disturbances are frequent west of SR-14, ranging
from historically disced scrublands to the active Nebeker Ranch, which supports alfalfa and small grains
52
Leitner, 2001.
53
ESA, 2003.
54
Karl, 2001.
55
www.mojavedata.gov/ documents/edwards.
56
Hickman, 1993.
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production. Those areas located east of SR-14 and west of EAFB have generally not been disturbed by
agriculture and occur in a relatively native state. Most of the area within the eastern agricultural area has
been disced for agriculture in the past. Only a few small areas of relatively undisturbed shadscale scrub
remain.
Shadscale scrub is a saltbush scrub community and is the most widespread plant community west of
Rosamond Dry Lake and in the area proposed for storage reservoirs.57 A few small areas of shadscale
scrub are also located within the eastern agricultural area. In the proposed storage reservoir area, the
shadscale community can be further subdivided into three plant associations: (1) the shadscale-saltgrass
(Distichlis spicata) association, (2) the shadscale-inkweed (Suaeda moquinii) association, and (3) the
shadscale-dropseed (Sporobolus airoides) association. Other common species identified in the shadscale
scrub community are matchweed (Guterrizia microcephala), desert alyssum (Lepidium fremontii),
rabbitbrush, tumbleweed (Salsola australis), and ragweed (Ambrosia acanthicarpa).
Other vegetation species found in the proposed storage reservoir area include a dense stand of salt cedar
(Tamarix sp.) and a few isolated Great Basin sage in less disturbed areas. California juniper (Juniperus
californica) and Joshua tree (Yucca brevifolia) were infrequently noted in this area.
The shadscale-saltgrass vegetative association was prevalent near the existing treatment facility, with
saltgrass becoming more scarce in the northern portion of the assessment area. The undisturbed shallow
depressions in the southeastern portion of the proposed storage reservoir area are dominated by shadscale
at higher elevation areas with saltgrass in low-lying areas. Portions of this salt-encrusted area are poorly
drained with moderately low permeability clay loam soils.
These areas include the non-succulent
perennial alkali heath (Frankenia grandifolia), as well as annual foxtail barley (Hordeum depressum),
alkali popcorn flower (Plagiobothrys bracteatus), and pineapple weed (Chamomilla suaveolens). The
alkali mariposa lily (Calochortus striatus) is reported within the proposed storage reservoir area.58
Further north, the saltgrass component drops out, with the inkweed and dropseed associations becoming
dominant.
57
Charlton, 1997.
58
CNDDB, 2001.
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Piute Ponds
East of the LWRP on EAFB, Piute Ponds support approximately 400 acres of freshwater marsh and
alkaline meadow habitat. The Piute Ponds area consists of two distinct plant communities, namely the
natural shadscale scrub community and an artificial aquatic habitat within the created ditches and ponds.
The habitat stops abruptly at the edge of the Rosamond Dry Lake. The dry lake itself is denuded of any
vegetation. The ponds are not particularly diverse from a vegetative perspective, but a combination of
their strategic location along the Pacific Flyway, large size, and the large amount of vegetative forage and
cover provide an important resource bank for native and migratory wildlife species, particularly birds.
The location of Piute Ponds relative to the proposed storage reservoir area is shown in Figure 3-1.
Narrow-leaved cattail (Typha latifolia) and tule (Scirpus actuatus) are the dominant species in the ponds,
forming dense stands adjacent to the artificial berms and dikes. Trees that grow along the pond edges
include Fremont’s cottonwood (Populus fremontii), narrow leaf willow and black willow (Salix exigua
and S. gooddingii), and salt cedar (Tamarisk chinensis). Other common species identified at the ponds
are smartweed (Polygonum sp.), curly dock (Rumex crispus), pond weed (Potomogeton pectinatus),
stinging nettle (Urtica holosericea), spikeweed (Hemizonia pungens), and saltgrass.
Several shallow pools supporting marsh vegetation exist in the uneven terrain around the perimeter of the
ponds and between the Rosamond Dry Lake and C-Dike. A few shorebirds have been observed in these
buffer areas on the muddy edges of pools. Some of the ponds are too deep for wading birds. The
hydraulics of these transitional marshy areas north of C-Dike are not well understood, but they appear to
be permanently wetted by seepage from under the dike. This is especially likely for the western half of
the transitional marshy area north of C-Dike which is clearly wetted by seepage from under the buffer
pond dike. (The location of the buffer pond is shown on Figure 3-2.). It appears likely that the
transitional marshy area between C-Dike and the flat dry lake bed will remain wetted even after the
elimination of overflows.
Wildlife Within the Assessment Area
Wildlife of Piute Ponds and Rosamond Dry Lake
A diverse array of resident and migratory birds is associated with the Piute Ponds habitat. The Piute
Ponds area supports over two hundred species of birds, indicative of the high biological importance and
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high productivity of this area.59 Aquatic birds are represented by a wide variety of grebes, geese, ducks,
plovers, sandpipers, gulls, and terns. Dry land habitats near Piute Ponds are equally diverse, supporting
many flycatchers, hummingbirds, thrushes, wood warblers, and sparrows, among others. While some
resident and migratory aquatic birds and songbirds that inhabit Piute Ponds occasionally breed or forage
in the project assessment area, the sparse desert scrub over much of the assessment area provides optimal
habitat for relatively few species.
Piute Ponds is valuable in the context of its location, but there are several aspects that limit its use by
waterfowl. Littoral vegetation around the ponds is almost entirely bulrush (Scirpus sp.) and tamarisk
(Tamarix). The water appears to be too deep (averaging four feet with some areas to eight feet) for
emergent aquatic vegetation, and while the area clearly has value as a brood pond and resting area, the
ability of Piute Ponds to provide forage for migrating waterfowl is limited. Migrating waterfowl are
predominantly “dabblers” that need suitable forage plants at a water depth not exceeding about 12 inches.
Piute Ponds are used by shorebirds both during migration and by over-wintering birds. Peak migration
times are from mid-March to early May and from July to September, but large numbers of shorebirds may
remain during the winter, depending on water and mudflat conditions. Associated raptors, including
peregrine falcons, also use the area, and their abundance coincides with shorebird abundance.60
Both Rosamond Dry Lake and the area between Piute Ponds and the lake edge provide important
shorebird feeding grounds.61 Shorebird abundance in these areas appears to be associated with the
presence of overflow from Piute Ponds, with diminished bird numbers in years with low flows. The area
immediately north of C-Dike maintains nearly constant saturation as a result of Piute Pond overflows and
seepage from under the dikes. These flows have created an abundant invertebrate food source for
migratory birds.
Evidence indicates that both the flooded area of Rosamond Dry Lake and the flooded area near C-Dike is
important to shorebirds because of the combination of appropriate foraging habitat (shallow water and
exposed mud areas) and appropriate prey (soil-dwelling invertebrates).
Overflows provide the
appropriate environment for invertebrate production which attracts large numbers of shorebirds including
Calidris sandpipers and dowitchers (Limnodromus sp.) that are often the most common species in the
59
EAFB, 1989.
60
Garrett pers. comm., 2001.
61
Ibid.
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shallow ponds that form close to C-Dike.62 Other shorebirds include American avocets and black-necked
stilts.
While some shorebird populations along the Pacific Flyway are apparently stable, others are declining.
During migration, enormous numbers of shorebirds pass through a relatively small number of vital
staging areas where food is available to them at the appropriate time of the year, and they can replenish
the fat supplies they require for migration.63 A USFWS publication states that the loss of wetland habitat
is the greatest reason for shorebird declines. Piute Ponds and Rosamond Dry Lake are utilized in the
Pacific Flyway.
The ubiquitous California toad (Bufo boreas halophilus), Pacific chorus frog (Pseudacris regilla), and
red-spotted toad (Bufo punctatus) occur in and around Piute Ponds.64 The African clawed frog (Xenopus
laevis) is also present at Piute Ponds.65 The distribution of these species within the assessment area is
limited due to the distance from breeding sites and lack of suitable cover in these areas. As a result,
unmodified upland portions of the assessment area west of SR-14 are considered to provide minimal
habitat with better habitat located in the immediate proximity of Piute Ponds and its tributary canal.
Wildlife Outside of Piute Ponds
Wildlife resources within the upland vegetative community are relatively uniform across the assessment
area from the eastern agricultural area to the western agricultural area. The shadscale scrub plant
community supports similar desert wildlife species, whether alone or when associated with co-dominant
species such as rabbitbrush or saltgrass. Soils within the assessment area are composed of silt and siltyclay and are notably more clay-based near Rosamond Dry Lake.
During reconnaissance surveys
conducted in 2001, evidence of flooding and ponding was found between SR-14 and the EAFB western
boundary and were observed to be less conspicuous elsewhere. The gradient in soil types and salinity
affect wildlife distribution, especially among invertebrate species that depend upon seasonal ponding.
As a result of increasing salinity and increased seasonal ponding, habitat for common fairy shrimp species
occurs in ephemeral pools located between SR-14 and EAFB. Three common fairy shrimp occur in the
62
Ibid.
63
Ehrlich et al., 1988.
64
Jennings, 1996.
65
Crayon, 1996.
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region, one of which was recorded in the assessment area near the Sierra Highway.66 Both the versatile
fairy shrimp (Branchinecta lindahli) and alkali fairy shrimp (B. mackini) are expected in ponding features
in the assessment area. During the reconnaissance surveys conducted in 2001, several small pools that
could support these species were observed adjacent to the railroad tracks that traverse the assessment area.
The giant fairy shrimp (B. gigas) is not expected in the assessment area due to a lack of large ponds.67
The occurrence of amphibian species in the assessment area is primarily limited to upland and aquatic
habitats associated with Piute Ponds. Seasonal ponding throughout the assessment area may provide
short-term habitat, but not breeding habitat, for local amphibians. Snake species that are expected in the
assessment area include the glossy snake (Arizona elegans) and the California kingsnake (Lampropeltis
getula californiae), which would occur in open sandy areas with scattered brush such as near Piute Ponds.
Lizards identified during biological surveys include desert night lizard (Xantusia vigilis vigilis), the
yellow-backed spiny lizard (Sceloporus magister uniformis), the Great Basin whiptail (Cnemidophorus
tigris tigris), and the California side-blotched lizard (Uta stansburiana elegans).68 Habitat for these
species is considered most suitable in the vicinity of Piute Ponds and inlet channels due to their high
biological productivity. The Great Basin whiptail was identified throughout the assessment area and the
other herpetofauna likely have broad distribution as well.
Birds identified in the assessment area outside of marsh-type areas include the California horned lark
(Eremophila alpestris), the sage sparrow (Amphispiza belli), the western kingbird (Tyrannus verticalis),
the American crow (Corvus brachyrhynchos)common raven (Corus corax), and the red-tailed hawk
(Buteo jamaicensis). Throughout the dry land portions of the assessment area, other resident bird species
include the greater roadrunner (Geococcyx californianus), the California towhee (Pipilo crissalis), the
loggerhead shrike (Lanius ludovicianus), Brewer’s sparrow (Spizella breweri), the western meadowlark
(Sturnella neglecta), the cactus wren (Campylorhynchus brunneicapillus), the California quail (Callipepla
californica), and the great horned owl (Bubo virginianus).69
Mammalian species in the assessment area include the deer mouse (Peromyscus maniculatus), the cactus
mouse (P. eremicus), the desert woodrat (Neotoma lepida), the desert cottontail (Sylvilagus audubonii),
kit fox (Vulpes macrotis), and the coyote (Canis latrans).
66
DFG, 2001.
67
Eriksen and Belk, 1999.
68
DFG, 1999; Jennings, 1996.
69
EAFB, 1991.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
infrequently identified in the assessment area, their absence possibly a result of the hard, clay-based soils.
Rabbit and coyote signs were frequently encountered throughout the assessment area.
Special Status Species
Special status plant and animal species are those that are designated through a federal, state, or local
process and regulated by a specific statute and/or the CEQA process. A full description of how these
species are defined and designated and the regulatory framework or federal, state, and local regulations
addressing such species are presented in Section 4.4.2. The following sections describe the special
species within the assessment area.
Plants
There are 12 special status plants known or with potential to occur in the regional vicinity of the LWRP,
EAFB, or near Lancaster. These species are listed in Table 4.4-1. Only one of the special status plant
species potentially occurring in the general project region is federally listed. No reports of this species
(Hoover’s eriastrum, Eriastrum hooveri) have been made within the assessment area.
Table 4.4-1
Special Status Plant Species Observed or Potentially Present in the Assessment Area
PLANT SPECIES
COMMON NAME
(SCIENTIFIC NAME)
Lancaster milkvetch
(Astragalus preussii var.
laxiflorus)
Alkali mariposa lily
(Calochortus striatus)
Pygmy poppy (Canbya
candida)
Parry’s spineflower
(Chorizanthe parryi var.
parryi)
Mojave spineflower
(Chorizanthe spinosa)
Desert cymopterus
(Cymopterus deserticola)
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SITE OCCURRENCE
Known to occur near
Lancaster (CNPS, 2000)
Observed in 1993 and 1995
at EAFB (TetraTech, 1995c);
Observed in 1995 along
Sierra Highway near Avenue
G (DFG, 2003a)
Observed in 1995 at EAFB
(Tetra Tech, 1995c)
Observed in 1896 in general
vicinity of Lancaster (DFG,
2003a)
Observed in 1995 at EAFB
near Rosamond Dry Lake
(Tetratech, 1995a)
Observed in 1993 at EAFB
(EAFB, 1993)
4-87
SURVEY /
IDENTIFICATION
PERIOD
April – May
STATUS
USFWS/DFG /
CNPS
--/--/List 1B
April – June
--/--/List 1B
April – May
--/--/List 1B
April – June
--/--/List 3
April – July
--/--/List 4
March – May
FSC/--/List 1B
May 2004
Chapter 4 Environmental Setting, Impacts, and Mitigation
Table 4.4-1
Special Status Plant Species Observed or Potentially Present in the Assessment Area (cont.)
PLANT SPECIES
COMMON NAME
(SCIENTIFIC NAME)
Hoover’s eriastrum
(Eriastrum hooveri)
Barstow wooly sunflower
(Eriophyllum mohavense)
Golden goodmania
(Goodmania luteola)
Sagebrush loeflingia
(Loeflingia squarrosa var.
artemisiarum)
Crowned onion (Muilla
coronata)
Parish’s alkali grass
(Puccinellia parishii)
SITE OCCURRENCE
CNPS identifies as possible
in LA county, although no
observations have been
reported in assessment area.
Observed in 1995 at EAFB
(Tetra Tech, 1995d).
Observed in 1995 at EAFB
near Rosamond Dry Lake
(Tetra Tech, 1995a)
Observed within 0.5 miles of
the LWRP (DFG, 2003a)
Observed 1977 at EAFB
(CalFlora, 2001)
No observations in area
SURVEY /
IDENTIFICATION
PERIOD
March – July
STATUS
USFWS/DFG /
CNPS
FT/--/List 4
April – May
FSC/--/List 1B
April – August
--/--/List 4
April – May
--/--/List 2
March – April
--/--/List 4
April – May
--/--List 1B
Status Codes:
USFWS
FSC = Federal Species of Concern
CNPS
List 1A = Plants presumed extinct in California
List 1B = Plants rare, threatened, or endangered in California
List 2 = Plants rare, threatened, or endangered in California, but more
common elsewhere
List 3 = Plants about which more information is needed
List 4 = Plants of limited distribution
"--" = No Special status
The rare plant survey conducted in areas proposed for storage reservoirs north, south, and west of the
LWRP identified three of these species: alkali mariposa lily (Calochortus striatus), Mojave spineflower
(Chorizanthe spinosa), and golden goodmania (Goodmania luteola). The alkali mariposa lily is a CNPS
List 1B species (rare, endangered or threatened in California). The other two species are CNPS List 4
species (limited distribution). Appendix I includes the Rare Plant Survey Report showing the distribution
of identified specimens within the surveyed areas. No other special status plants were identified within
the surveyed areas surrounding the LWRP.
The alkali mariposa lily was observed in abundance in areas surrounding the LWRP. The West Mojave
Plan proposes that conservation areas be established for the lily in the area. Figure 4.4-1 shows the lily
conservation areas proposed in the West Mojave Plan.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
Wildlife
Table 4.4-2 lists the federally and state listed species potentially occurring within the assessment area. A
discussion of each species and the availability of suitable habitat in the assessment area is included in
Appendix K of this document.
Table 4.4-2
Special Status Wildlife Species Potentially Occurring Within the Assessment Area
SPECIES NAME
COMMON NAME
(SCIENTIFIC NAME)
SITE OCCURRENCE
STATUS
USFWS/ DFG
Threatened and Endangered Species
Reptiles
Desert tortoise
Gopherus agassizii
The Stage V construction area provides poor quality
habitat for this species; critical habitat located roughly
14 miles east of LWRP (EAFB, 1996; CNDDB, 2001;
Karl, 2001).
FT/CT
Swainson’s hawk
Buteo swainsoni
Identified nesting site roughly 7.5 miles southeast of the
Stage V construction area in 1999; potential nesting
habitat occurs at the Piute Ponds area (CNDDB, 2001).
FT/--
Western snowy plover
Charadrius alexandrinus
nivosus (nesting)
Nesting reported at Rosamond Dry Lake in 1978
(CNDDB, 2001); nests with regularity at Piute Ponds
(Draft West Mojave Plan, 1999).
Coastal
FT/CSC
Birds
Inland
CSC
Peregrine falcon
Falco peregrinus
Identified sporadically at Piute Ponds during migration
periods (EAFB, 1989).
--/CE
Bald eagle
Haliaeetus
leucocephalus
Identified sporadically at Piute Ponds during migration
periods (EAFB, 1989).
FT/CE
Identified in 1973 3.8 miles north of Stage V project
boundary in the town of Rosamond (Leitner, 2001;
CNDDB, 2001).
FSC/CT
Mammals
Mohave ground squirrel
Spermophilus
mohavensis
Species of Special Concern
Reptiles
San Diego horned lizard
Phrynosoma coronatum
blainvillei
Nearest occurrence is documented 9.5 miles southwest
of the LWRP. Potential habitat available in the Stage V
construction area.
FSC/CSC
Cooper’s hawk
Accipiter cooperi
Potential nesting habitat occurs at Piute Ponds;
documented at EAFB (EAFB, 1991).
--/CSC
Tricolored blackbird
Agelaius tricolor
Nesting colony identified in Piute Ponds in 1992
(CNDDB, 2001).
FSC/CSC
Birds
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Table 4.4-2
Special Status Wildlife Species Potentially Occurring Within the Assessment Area (cont.)
SPECIES NAME
COMMON NAME
(SCIENTIFIC NAME)
SITE OCCURRENCE
STATUS
USFWS/ DFG
Species of Special Concern (cont.)
Golden eagle
Aquila chrysaetos
Nests on cliffs in rugged mountain ranges.
habitat may occur in the assessment area.
Foraging
--/CSC
Short-eared owl
Asio flammeus
Nests near marshes and seasonal wetlands at Piute
Ponds (West Mojave Plan, 1999).
--/CSC
Long-eared owl
Asia otus
Nests in riparian groves of willows and cottonwoods,
such as those at Piute Ponds.
--/CSC
Burrowing owl
Athene cunicularia
Nesting pair identified in saltbrush scrub 3 miles east of
the Stage V project boundary; suitable habitat in the
Stage V construction area.
--/CSC
Northern harrier
Circus cyaneus
Nests on the ground near freshwater marshes such as
Piute Ponds.
--/CSC
White-tailed kite
Elanus leucurus
Occurs seasonally at Piute Ponds; nesting status not
known (EAFB, 1989).
--/Fully
Protected
California horned lark
Eremophila alpestris
actia
In both December 2000 and August 2001, flocks of at
least 50 birds were observed foraging east of SR-14.
Nesting habitat available throughout assessment area.
--/CSC
Prairie falcon
Falco mexicanus
Nests on cliffs in rugged mountain ranges.
habitat may occur in the assessment area.
Foraging
--/CSC
Loggerhead shrike
Lanius ludovicianus
Identified on site in 2000 by ESA biologists with potential
nesting habitat found in Tamarisk stands and elsewhere
on site.
--/CSC
Le Conte's thrasher
Toxostoma lecontei
Found in creosote bush scrub with cholla cactus,
Joshua trees, and thorny shrubs. Habitat considered
poor in assessment area.
FSC/CSC
Locally identified occurrences with potential habitat near
Piute Ponds (EAFB, 1993b).
--/CSC
Mammals
American badger
Taxidea taxus
Status Codes:
FT = Federal Threatened
FSC = Federal Species of Concern
CE = California Endangered
CT = California Threatened
CSC = California Species of Special Concern
Fully Protected = California Fully Protected Species
"--" = No status
Special status wildlife species potentially in the project vicinity include the Mohave ground squirrel
(Spermophilus mohavensis), the desert tortoise (Gopherus agassizi), resident birds such as loggerhead
shrike (Lanius ludovicianus), and nesting raptors such as the Swainson’s hawk (Buteo swainsoni).
Although the shrike and raptors may utilize the area for foraging, only the Mohave ground squirrel is a
potential (although unlikely) permanent resident within the assessment area, and only east of SR-14. A
preliminary site assessment was conducted for the proposed storage reservoir area and for the eastern
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agricultural area by Dr. Phil Leitner, a biologist who specializes in Mohave ground squirrel. The survey
report is included in Appendix J of this report.
No evidence of the desert tortoise was observed within the assessment area.
A literature survey
conducted by a qualified biologist who specializes in the desert tortoise, Alice Karl, indicated that the
likelihood of encountering desert tortoise in the assessment area was slight. A copy of the survey is
included in Appendix J of this report.
As a result of local seasonal ponding, habitat for common fairy shrimp species occurs in isolated puddles
and pools located east of SR-14 to Rosamond Dry Lake. However, the assessment area is located well
outside of the known range for the federally listed endangered Riverside fairy shrimp (Streptocephalus
woottoni),70 thus this species is not expected within the assessment area. Listed fairy shrimp species have
not been identified in the regional project vicinity and are thus excluded from this discussion of specialstatus wildlife.71
Conclusions Regarding the Presence of Special-Status Animals
The following conclusions were reached by the surveying biologists regarding the presence or absence of
the 22 special status wildlife species potentially found within the assessment area:
Special Status Species Potentially Within the Assessment Area
•
Cooper’s hawk is a probable visitor to Piute Ponds, but an unlikely breeder. Habitat use is restricted
to the vegetated woodlands associated with the ponds.
•
The tricolored blackbird is a likely winter visitor to Piute Ponds that occasionally breeds in the dense
marshlands (last reported in 1992). Their infrequent habitat use is considered incidental.
•
The golden eagle is a wide-ranging species that may forage on the site during both the breeding and
non-breeding seasons. This potential use of the site by the golden eagle is considered incidental.
•
Both the short-eared owl and long-eared owl are documented locally and may nest at Piute Ponds.
70
Eriksen and Belk, 1999; CNDDB, 2001.
71
Branchiophod Research Group, 1993; Eriksen and Belk, 1999; CNDDB, 2001.
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•
Burrowing owls were identified within the shadescale scrub areas within the eastern agricultural area.
Burrowing owls were not identified west of EAFB, but suitable breeding habitat may occur in the
proposed storage reservoir area. The site contains suitable foraging habitat.
•
Similar to the Cooper’s hawk, Swainson’s hawk is a probable visitor to Piute Ponds, but an unlikely
breeder. Habitat use is restricted to the vegetated woodlands associated with the ponds.
•
The northern harrier is expected to breed and forage in the marsh-like habitats surrounding Piute
Ponds.
•
Western snowy plover nest at Piute Ponds, though the distribution of nesting habitat is not fully
known. This species is expected to rely on overflows from Piute Ponds to Rosamond Dry Lake for
suitable forage.
•
White-tailed kites are potential foragers in the dry land portions of the assessment area and unlikely
nesters, with the exception of the Piute Ponds area where Fremont’s cottonwood, willow, and other
trees provide nesting habitat.
•
The peregrine falcon and bald eagle are potential visitors to the Piute Ponds area. Use of this area by
these species is considered incidental.
•
The desert scrub habitat that occurs in the proposed storage reservoir area is considered to meet the
nesting and foraging habitat requirements for loggerhead shrike, Le Conte’s thrasher, and California
horned lark.
•
The presence of the Mohave ground squirrel in the assessment area is not likely due to the poor
quality habitat. However, the eastern half of the assessment area is within the species’ historical
range.
•
The American badger may be present throughout the assessment area.
Special Status Species Not Likely to be Found Within the Assessment Area
•
Listed fairy shrimp species are assumed absent from the assessment area.
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•
Mojave fringe-toed lizards are assumed not to occur in the proposed storage reservoir area, but may
occur in sand fields, dunes, or other blowsand habitat located between Rosamond Dry Lake and the
LWRP.
•
San Diego horned lizards are considered absent from the assessment area, based on the unsuitability
of the habitat and known distribution of this species.
•
Silvery legless lizards are presumed absent from the proposed storage reservoir area based on the
absence of suitable habitat, but could occur in blowsand habitat on EAFB located between Rosamond
Dry Lake and the LWRP.
•
Based on historical distribution and the absence of any sign during surveys, the desert tortoise is
considered absent from the assessment area.
Marsh-Type Habitat and Waters of the United States Within the Assessment Area
Marsh-type habitat was observed surrounding Piute Ponds and between C-Dike and the mudflats of
Rosamond Dry Lake. No marsh-type habitats were observed west of Sierra Highway or south of EAFB.
East of the Sierra Highway to Rosamond Dry Lake, the landforms create a network of mounded
hummocks and low claypans that seasonally pond. Clayey floodplain soils are highly suitable for
moisture-adapted grasses and herbs. As a result, marginally hydrophytic plant communities are dispersed
among the claypan depressions. The low areas flood seasonally and are sparsely to densely vegetated
with an unidentified spineflower (Chorizanthe sp.), a wetland indicator species. It is estimated that
between three and five acres of claypan depressions are interspersed throughout the southeastern portion
of the proposed storage reservoir area. No claypan depressions or other wetlands were observed in the
western or eastern agriculture areas. The known distribution of potential claypan depression features in
the assessment area is shown in Figure 4.4-2. Figure 4.4-3 shows a photograph of a typical claypan
depression.
The Corps has indicated to District No. 14 and to the cities of Palmdale and Lancaster that the entire
Amargosa Creek watershed is not considered a water of the U.S. as defined in the CWA. As such, none
of the surface waters are subject to permitting regulations overseen by the Corps (see Regulatory Setting
Section to follow). Due to the large size of the assessment area and patchy distribution of claypan
depressions, a comprehensive field characterization of depressions in the assessment area has not been
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LWRP
Not to Scale
Widely Scattered Claypan Depressions
Area of Greatest Density of Claypan Depressions
Edwards Air Force Base Boundary
0
1
Mile
SOURCE: Environmental Science Associates
LWRP 2020 Plan EIR / 200481
Figure 4.4-2
Distribution of Claypan Depressions West of Edwards Air Force Base
SOURCE: Environmental Science Associates, Dec. 2000
LWRP 2020 Plan EIR / 200481
Figure 4.4-3
Typical Claypan Depression
Chapter 4 Environmental Setting, Impacts, and Mitigation
conducted. However, similar depressions assessed by the Corps within EAFB were found not to meet the
Corps’ criteria for a wetland.
4.4.2
Regulatory Background
Wetlands Regulations
The regulations and policies of various federal agencies (e.g., the Corps, EPA, and USFWS) mandate that
the filling of wetlands be avoided unless it can be demonstrated that no practicable alternatives exist. The
Corps has the primary federal responsibility for administering regulations that concern waters and
wetlands. In this regard, the Corps acts under two statutory authorities, the Rivers and Harbors Act
(Sections 9 and 10), which governs specified activities in navigable waters, and the CWA (Section 404),
which governs specified activities in waters of the U.S., including wetlands and special aquatic sites. The
Corps requires that a permit be obtained if a project proposes placing structures within navigable waters.
The EPA, USFWS, and several other agencies provide comment on Corps permit applications. The EPA
has provided the primary criteria for evaluating the biological impacts of Corps permit actions in wetlands
and other special aquatic sites.
The Corps has recently indicated that Amargosa Creek and Piute Ponds are not considered waters of the
U.S. as defined in the CWA and are therefore not within their jurisdiction to regulate under Section 404 of
the CWA.
The state’s authority in regulating activities in wetlands and waters at the site resides primarily with the
DFG and the SWRCB.
Coordination Act.
DFG comments on Corps permit actions under the Fish and Wildlife
In addition, DFG has jurisdiction over streams and riparian habitat pursuant to
Sections 1601-1603 of the Fish and Game Code, which requires a Streambed Alteration Agreement for
modifications to stream aquatic habitat or supporting riparian vegetation.
A comprehensive delineation of wetlands within the assessment area has not been completed. However,
portions of the assessment area subject to the jurisdiction of the aforementioned agencies may include all
or portions of (1) a series of small claypan depressions that are bordered by EAFB to the east, Avenue C
to the North, the Sierra Highway to the west, and existing storage reservoirs to the south, and (2) the Piute
Ponds marsh-type habitat, including the overflow area to Rosamond Dry Lake.
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Special Status Species Regulations
Federal Endangered Species Act (ESA)
Under the ESA, the Secretary of the Interior and the Secretary of Commerce jointly have the authority to
list a species as threatened or endangered.72 Pursuant to the requirements of the ESA, an agency
reviewing a proposed project within its jurisdiction must determine whether any federally listed or
proposed species may be present in the project region and determine whether the proposed project would
have a potentially significant impact on such species. In addition, the agency is required to determine
whether the project is likely to jeopardize the continued existence of any species proposed to be listed
under the ESA or result in the destruction or adverse modification of critical habitat proposed to be
designated for such species.73
Project-related impacts to these species or their habitats would be
considered “significant.” The “take” 74 prohibition of the ESA prohibits any action that adversely affects
a single member of an endangered or threatened species.
California Endangered Species Act
Under the Cal-ESA, DFG is responsible for maintaining a list of threatened and endangered species,75
candidate species, and species of special concern. Pursuant to the requirements of Cal-ESA, an agency
reviewing a proposed project within its jurisdiction must determine whether any state-listed endangered
or threatened species may be present on the project region and determine whether the proposed project
would have a potentially significant impact on such species. In addition, DFG encourages informal
consultation on any proposed project that may impact a candidate species. Project-related impacts to
species on the Cal-ESA threatened and endangered list would be considered significant. Impacts to
species of concern would be considered significant under certain circumstances, as discussed below.
72
16 USC 1533(c).
73
16 USC 1536(3), (4).
74
“Take,” as defined in Section 9 of the ESA, is broadly defined to include intentional or accidental “harassment” or “harm” to
wildlife. “Harass” is further defined by the USFWS as an intentional or negligent act or omission which creates the
likelihood of injury to wildlife by annoying it to such an extent as to significantly disrupt normal behavioral patterns which
include, but are not limited to, breeding, feeding, and sheltering. “Harm” is defined as an act which actually kills or injures
wildlife. This may include significant habitat modification or degradation where it actually kills or injures wildlife by
significantly impairing essential behavioral patterns, including breeding, feeding or sheltering.
75
California Fish and Game Code 2070.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
CEQA Guidelines Section 15380
Although threatened and endangered species are protected by specific federal and state statutes, CEQA
Guidelines Section 15380(b) provides that a species not listed on the federal or state list of protected
species may be considered rare or endangered if the species can be shown to meet certain specified
criteria. These criteria have been modeled after the definition in ESA and the section of the California
Fish and Game Code dealing with rare or endangered plants or animals. This section was included in the
CEQA Guidelines primarily to deal with situations in which a public agency is reviewing a project that
may have a significant effect on, for example, a candidate species that has not yet been listed by either the
USFWS or DFG. Thus, CEQA provides an agency with the ability to protect a species from a project’s
potential impacts until the respective government agencies have an opportunity to designate the species as
protected, if warranted.
Other Statutes, Codes, and Policies Affording Limited Species Protection
The federal Migratory Bird Treaty Act (MBTA)76 prohibits killing, possessing, or trading in migratory
birds except in accordance with regulations prescribed by the Secretary of the Interior.
encompasses whole birds, parts of birds, and bird nests and eggs.
This act
Birds of prey are protected in
California under the State Fish and Game Code, Section 3503.5 1992. Section 3503.5 states that it is
“unlawful to take, possess, or destroy any birds in the order Falconiformes or Strigiformes (birds of prey)
or to take, possess, or destroy the nest or eggs of any such bird except as otherwise provided by this code
or any regulation adopted pursuant thereto.” Construction disturbance during the breeding season could
result in the incidental loss of fertile eggs or nestlings, or otherwise lead to nest abandonment.
Disturbance that causes nest abandonment and/or loss of reproductive effort is considered “taking” by
DFG. Any loss of fertile eggs, nesting raptors or any activities resulting in nest abandonment would
constitute a significant impact. This approach would apply to red-tailed hawks, American kestrels, barn
owls, and other birds of prey. Project impacts to these species would not be considered significant in this
LWRP 2020 Plan EIR unless they are known or have a high potential to nest on the site or rely on it for
primary foraging.
The federal Bald Eagle Protection Act prohibits persons within the U.S. (or other places subject to U.S.
jurisdiction) from “possessing, selling, purchasing, offering to sell, transporting, exporting, or importing
any bald eagle or any golden eagle, alive or dead, or any part, nest, or egg thereof.”
76
16 U.S.C., Sec. 703, Supp. I 1989.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
Vascular plants listed as rare or endangered by the CNPS,77 but which have no designated status or
protection under federal or state endangered species legislation, are defined as follows:
List 1A: Plants believed extinct
List 1B: Plants Rare, Threatened, or Endangered in California and Elsewhere
List 2:
Plants Rare, Threatened, or Endangered in California, but More Numerous Elsewhere
List 3:
Plants about which we need more information – a review list
List 4:
Plants of limited distribution – a watch list
In general, plants appearing on CNPS List 1 or 2 are considered to meet CEQA’s Section 15380 criteria
and effects to these species are considered “significant.” In general, project effects to List 3 and 4 plants
are noted as potential impacts that would not be considered significant.
The West Mojave Plan
The West Mojave Plan, being jointly prepared by agencies having administrative responsibility or
regulatory authority over species of concern within the planning area, defines a regional strategy for
conserving plant and animal species and their habitats and defines an efficient, equitable, and costeffective process for complying with threatened and endangered species laws. The plan has not yet been
adopted by the Bureau of Land Management. In May 2003, the Bureau of Land Management, the County
of San Bernardino, and the City of Barstow issued a joint EIR/EIS for the plan. Once adopted, the plan
will enable the USFWS and DFG to issue programmatic biological opinions. The plan area extends from
Olancha in Inyo County on the north to the San Gabriel and San Bernardino Mountains on the south, and
from the Antelope Valley on the west to the Mojave National Preserve on the east. The assessment area
is within the West Mojave Plan planning area.
None of the Desert Wildlife Management Areas or Critical Habitat Units described in the West Mojave
Plan include any portion of the assessment area of the proposed LWRP expansion. The assessment area
lies within the low emphasis area for desert tortoise. The plan identifies proposed conservation areas for
the alkali mariposa lily in areas surrounding the LWRP and extending further west, encompassing the
western agricultural area.
77
Skinner and Pavlik, 2000.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
County of Los Angeles Significant Ecological Areas
The Los Angeles County SEA #50 currently encompasses the Rosamond Dry Lake.
The County
Department of Regional Planning is considering replacing this SEA with the proposed Antelope Valley
SEA #7. The proposed SEA stretches across the south-central portion of the Antelope Valley, extending
from Little Rock and Big Rock Washes downstream to the valley floor and northward, encompassing
Rogers, Rosamond, and Buckhorn Dry Lakes.78 The proposed location of a portion of the storage
reservoirs and the eastern agricultural area would be within the boundaries of SEA #7 as currently
proposed by the County. Figure 4.1-13 shows the boundary of the proposed SEA #7.
4.4.3
Environmental Impacts and Mitigation Measures
Thresholds of Significance
To determine the level of significance of an identified impact, the criteria outlined in the CEQA
Guidelines were used. The following is a discussion of the criteria used to determine the significance of
impacts to biological resources.
CEQA (Section 15206) specifies that a project shall be deemed to be of statewide, regional, or area-wide
significance if it would substantially affect sensitive wildlife habitats including, but not limited to,
riparian lands, wetlands, bays, estuaries, marshes, and habitats for rare and endangered species as defined
by Fish and Game Code Section 903.
Appendix G of the CEQA Guidelines indicates that a project would have a significant effect on the
environment if it would:
•
Have a substantial adverse effect, either directly or through habitat modifications, on any species
identified as a candidate, sensitive, or special status species in local or regional plans, policies, or
regulations, or by DFG or USFWS.
•
Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified
in local or regional plans, policies, regulations or by DFG or USFWS.
78
PCR Services Incorporation. Biological Resources Assessment of the Proposed Antelope Valley Significant Ecological Area.
Prepared for Los Angeles County Department of Regional Planning. November 2000.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
•
Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the
CWA (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling,
hydrological interruption, or other means.
•
Interfere substantially with the movement of any native resident or migratory fish or wildlife species
or with established native resident or migratory wildlife corridors, or impede the use of native wildlife
nursery sites.
•
Conflict with any local policies or ordinances protecting biological resources, such as a tree
preservation policy or ordinance.
•
Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community
Conservation Plan, or other approved local, regional, or state habitat conservation plan.
•
Have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish
or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to
eliminate a plant or animal community, reduce the number or restrict the range of a rare or
endangered plant or animal.
CEQA Section 15380 further provides that a plant or animal species may be treated as “rare or
endangered” even if not on one of the official lists if, for example, it is likely to become endangered in the
foreseeable future.
For the purposes of this LWRP 2020 Plan EIR, three principal components of the guidelines outlined
above were considered:
•
Magnitude of the impact (e.g., substantial/not substantial)
•
Uniqueness of the affected resource (rarity)
•
Susceptibility of the affected resource to perturbation (sensitivity)
The evaluation of significance must consider the interrelationship of these three components.
For
example, a relatively small magnitude impact to a state or federally listed species would be considered
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Chapter 4 Environmental Setting, Impacts, and Mitigation
significant because the species is rare and is believed to be susceptible to disturbance. Conversely, a plant
community such as desert shadescale scrub is not necessarily rare or sensitive to disturbance. Therefore,
a much larger magnitude of impact would be required to result in a significant impact. Impacts are
generally considered less than significant if the habitats and species affected are common and widespread
in the region and the state. Impacts are considered beneficial if the action causes no detrimental impacts
and results in an increase of habitat quantity and quality.
Impact 4.4-1: Construction of storage reservoirs for Alternatives 1 and 2 would result in the loss of
alkali mariposa lily and other sensitive plants. The conversion of previously undeveloped areas in
the eastern and western agricultural areas for each Alternative could also result in loss of sensitive
plants.
The alkali mariposa lily (a CNPS List 1B species) has been identified in the assessment area near the
LWRP. The population that occurs in the assessment area constitutes a portion of one of 36 alkali
mariposa lily populations reported on or adjacent to EAFB.79 The West Mojave Plan EIR/EIS identifies
“conservation areas” for the lily as shown in Figure 4.4-1.
A sensitive plant survey was conducted in May of 2003 in the areas proposed for storage reservoirs under
Alternatives 1 and 2. The lily was identified in this area patchily distributed and estimated to number in
the hundreds to low thousands. In addition, two other special status plants were observed in the proposed
storage reservoir area. The rare plant survey identified specific locations of the lily within the proposed
storage reservoir area using global positioning system (GPS) coordinates. Figure 4.4-4 shows these
identified locations and provides a total acreage of impacted population area using geographic
information system (GIS) technology.
Within the proposed storage reservoir location, lilies were
identified within an area covering approximately 730 acres. Survey results for the alternate storage
reservoir locations are shown in Appendix I. The direct disturbance to and/or removal of a large portion
of the local lily populations would constitute a potentially significant impact of Alternatives 1 and 2.
Mitigation Measure 4.4-1 would minimize the impact to the lily population. Since no storage reservoirs
would be constructed under Alternatives 3 and 4, this would not be an impact of these alternatives.
The two other special status species identified in the rare plant survey (Mojave spineflower and golden
goodmania) are CNPS List 4 species. CNPS List 4 species are listed as sensitive due to a limited range.
The construction of storage reservoirs would eliminate some of the existing habitat within this limited
79
Tetra Tech, Inc., 1995c.
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Avenue B
731 Acres
Avenue C
way
Sierra High
Highway 14
LWRP
Avenue D
Alkali Mariposa Lily
Golden Goodmania
Mojave Spineflower
Study Areas
0
SOURCE: Environmental Science Associates
250
500
750
Meters
1,000
LWRP 2000 Plan EIR / 200481
Figure 4.4-4
Identified Alkali Mariposa Lily Population
within Proposed Storage Reservoir Area
Chapter 4 Environmental Setting, Impacts, and Mitigation
range. Nonetheless, the project would not affect the overall viability of the species. The removal of open
space supporting small numbers of CNPS List 4 species would not be considered significant.
Conversion of open space into agricultural land could result in destruction of rare plant habitat. Rare
plant surveys for the entire proposed agriculture areas were not performed for purposes of this
assessment. However, many properties within the proposed agriculture areas are already graded and do
not have potential to support rare or sensitive plants. Figure 4.4-5 identifies properties within the
proposed agriculture areas that exhibit signs of recent substantial disturbance, grading, or agriculture.
The remaining properties within the proposed agricultural areas exhibit some habitat value of varying
quality. Since the exact properties to be converted to agricultural use are not known, impacts to rare
plants from the conversion of previously undisturbed land to agriculture have not been quantified.
Implementation of Mitigation Measure 4.4-2 would ensure that impacts to existing rare plant populations
would be avoided.
Mitigation Measures
Alternatives 1 and 2
Mitigation Measure 4.4-1: District No. 14 shall provide for the long-term protection of alkali mariposa
lily habitat either by avoidance or acquisition of compensation lands near the LWRP at a replacement
ratio of either ½:1 or 1:1 (depending on the quality of each affected acre of alkali mariposa lily habitat) or
through the identification and conservation of habitat managed through the West Mojave Plan.
Alternatives 1, 2, 3, and 4
Mitigation Measure 4.4-2: District No. 14 shall conduct rare plant surveys of previously undisturbed
properties acquired for conversion to agriculture. A Rare Plant Survey Report shall be prepared and
submitted to DFG prior to clearing the properties. The Rare Plant Survey Report shall recommend
measures to avoid significant impacts to populations of rare plants identified on the properties.
Depending on the type of plants encountered and the quality of the populations, measures could include
transplanting individual specimens or providing compensatory conservation lands.
Significance After Mitigation
Less than significant.
_________________________
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Impact 4.4-2: The construction of storage reservoirs for Alternatives 1 and 2 would eliminate
seasonal claypan depressions.
The preliminary reconnaissance of the assessment area identified three to five acres of claypan
depressions that would be permanently destroyed by the installation of the storage reservoirs under
Alternatives 1 and 2. Figure 4.4-2 identifies the location of claypan depressions north of the LWRP. This
impact would not occur under Alternatives 3 and 4. Fairy shrimp indigenous to the region including the
versatile fairy shrimp (Branchinecta lindahli) and alkali fairy shrimp (B. mackini) could exist within these
depressions. The Corps has indicated that the Amargosa Creek watershed, including Piute Ponds, is not
officially designated as waters of the U.S. Therefore, the Corps does not appear to have jurisdiction over
the claypan depressions. In addition, EAFB and the Corps have conducted wetland delineations of
similar claypan depression features within the EAFB property and have concluded that the depressions do
not exhibit all the features necessary to be classified as wetlands. The claypan depressions surround
Rosamond Dry Lake and are not unique to the area north of the treatment plant. The fairy shrimp
potentially existing in these areas are not protected species, and the acreage affected by the project would
not substantially reduce the species’ viability. Similarly, the destruction of up to five acres of claypan
depressions would not substantially reduce the feature within the region. Therefore, this impact would be
considered less than significant.
Mitigation Measure
Alternatives 1, 2, 3, and 4
None required.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-3: The construction of storage reservoirs for Alternatives 1 and 2 and the conversion of
previously undeveloped areas in the eastern and western agricultural areas for each alternative
would cause the loss of potential habitat for burrowing owls, loggerhead shrike, Le Conte’s
thrasher, and California horned lark, as well as more common migratory birds that are protected
by the Migratory Bird Treaty Act (MBTA).
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Chapter 4 Environmental Setting, Impacts, and Mitigation
Burrowing owls are not expected to widely use the proposed storage reservoir area, but the local and
regional occurrence of nesting owls provides the potential for on site nesting by this species. Only
marginally suitable nesting habitat for burrowing owls appears to occur in the assessment area. It is
anticipated that impacts to the burrowing owl would be limited to the loss of foraging habitat, and would
less likely include the potential for direct mortality from construction equipment and harassment due to
noise or vibration.
Potential nesting and foraging habitat for the loggerhead shrike, Le Conte’s thrasher, and the California
horned lark occur within the assessment area, with both the shrike and horned lark identified on site
during the non-breeding season. Impacts to individual nesting loggerhead shrikes, Le Conte’s thrashers,
or California horned larks could occur if these species were nesting on or adjacent to the construction
areas at the time of construction.
Given the large amount of undeveloped nesting and foraging habitat for burrowing owls, the loggerhead
shrike, Le Conte’s thrasher, and the California horned lark in the Antelope Valley, and the large expanses
of habitat at the nearby EAFB, the loss of potential foraging habitat is not considered a significant impact.
As such, no mitigation is required for the loss of potential nesting or foraging habitat. The direct
mortality of owls, shrikes, thrashers, or larks as a result of project construction can be mitigated to a less
than significant level through the implementation of construction monitoring and standard DFG
mitigation guidelines for protecting burrowing owls. Furthermore, burrowing owls will benefit from any
compensation lands provided for alkali mariposa lily (see mitigation measure 4.4-1).
Mitigation Measure
Alternatives 1, 2, 3, and 4
Mitigation Measure 4.4-3: If project activities cannot avoid the breeding bird season (generally March 1
– August 31), District No. 14 shall conduct focused preconstruction breeding bird surveys to include
burrowing owl, loggerhead shrike, Le Conte’s thrasher, California horned lark, as well as other species
protected under the MBTA, in all areas that may provide suitable nesting habitat. For activities that occur
outside the breeding bird season (generally September 1 through February 28) such surveys would not be
required.
No more than two weeks before construction, a survey for burrows and burrowing owls would be
conducted by a qualified ornithologist. Surveys would conform to the protocol described by the
California Burrowing Owl Consortium (1993) which includes up to four surveys on different dates if
there are suitable burrows present. Surveys would include areas within 500 feet of the construction area
that provide potential burrowing owl nesting habitat (access permitting). Simultaneous with the owl
surveys, an assessment of the construction area would also be conducted to determine the nesting status of
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Chapter 4 Environmental Setting, Impacts, and Mitigation
loggerhead shrike, Le Conte’s thrasher, and California horned lark, and other birds protected by the
MTBA.
If any of the above species are identified, occupied nests or burrows would not be disturbed during the
nesting season (February 1 through August 31 for owls and other raptors; March 1 through August 31 for
other species), including a minimum 250-foot buffer zone around any occupied burrow or nest 150 feet
for other non-special status passerine birds, and up to 500 feet for raptors. During the non-nesting season,
District No. 14 would encourage owls to relocate from the Stage V construction disturbance area to offsite habitat area through the use of one-way doors on burrows. No relocation measures are required for
loggerhead shrike, Le Conte’s thrasher, or California horned lark during the non-breeding season.
District No. 14 shall conduct preconstruction surveys for burrowing owl, loggerhead shrike, Le Conte’s
thrasher, and California horned lark habitat by a qualified ornithologist prior to clearing undisturbed land.
If any of the above species are identified, occupied nests or burrows shall not be disturbed during the
nesting season, including a minimum 250-foot buffer zone around any occupied burrow or nest. If
burrowing owls are identified, they shall be relocated during the non-breeding season.
No mitigation measures are necessary.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-4: The construction of storage reservoirs for Alternatives 1 and 2 and the conversion of
previously undeveloped areas in the eastern agricultural area for each alternative would cause loss
of potential Mohave ground squirrel habitat and/or possible incidental take of Mohave ground
squirrel.
The LWRP is located on the western fringe of the Mohave ground squirrel’s habitat as identified by
DFG.80 As such, the potential exists for encountering this state-listed threatened species while clearing
land in the eastern agricultural area and within the proposed storage reservoir location. The western
agricultural area is considered west of and outside of the species’ known habitat. No Mohave ground
squirrel sightings have been made in the project vicinity. The potential for encountering the squirrel
within the proposed storage reservoir area or eastern agricultural area is minimal due to the habitat’s poor
suitability. However, if Mohave ground squirrel were present on the construction site, the project could
result in direct significant impacts to this species.
80
DFG, 1993.
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A Mohave ground squirrel assessment survey was conducted for the proposed storage reservoir area as
well as the eastern agricultural area in August and September 2001 (Appendix J). None of the areas
surveyed contained high quality Mohave ground squirrel habitat. However, some areas were identified
that could potentially provide habitat, albeit of low quality. Figures 4.4-6a and 4.4-6b show the locations
of potential Mohave ground squirrel habitat as identified by Phil Leitner in September 2001. If the
District No. 14 elects to purchase and convert land within these identified habitat zones, impacts to
Mohave ground squirrel could result. Implementation of the following mitigation measures would ensure
that potential impacts to the state-listed Mohave ground squirrel are identified and mitigated.
Mitigation Measures
Alternatives 1, 2, 3, and 4
Mitigation Measure 4.4-4: District No. 14 shall attempt to utilize pre-graded parcels for agriculture
where feasible to minimize grading of potential Mohave ground squirrel habitat.
Mitigation Measure 4.4-5: District No. 14 shall conduct absence surveys following modified protocol
guidelines as approved by DFG for Mohave ground squirrel in areas that could provide at least low
quality habitat for the species. The areas that would require such surveys are shown in Figures 4.4-6a and
4.4-6b of the Draft EIR. If no Mohave ground squirrels are found during these surveys, no other action
would be required to protect the species. However, if Mohave ground squirrels are found to be present,
Mitigation Measure 4.4-4 will be applicable. At its discretion, District No. 14 may forgo these protocol
surveys and only implement Mitigation Measure 4.4-6 requiring compensatory lands.
Mitigation Measure 4.4-6: If no DFG-approved absence surveys are conducted, or if these surveys
indicate the presence of Mohave ground squirrel, compensatory lands at a ½:1 to 1:1 ratio, depending on
the value of the habitat quality, shall be made available in perpetuity for the protection of the Mohave
ground squirrel for the conversion of any of the potentially suitable habitat areas shown on Figures 4.4-6a
and 4.4-6b of the Draft EIR. The location and conservation management of the identified compensatory
lands shall be approved by DFG pursuant to Section 2081 of the California Fish and Game Code.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-5: The construction of storage reservoirs for Alternatives 1 and 2 and the conversion of
previously undeveloped areas in the eastern and western agricultural area for each alternative
could disturb desert tortoise.
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KERN COUNTY
AVE A
LOS ANGELES COUNTY
ROSAMOND
DRY LAKE
AVE B
PIUTE PONDS
AVE C
LWRP
HWY
30TH ST W
SIERRA
0
R
ACIFIC R
UNION P
AVE D
IMPOUNDMENT
AREAS
EDWARDS AIR FORCE BASE
AVE E
Low Suitability Habitat
1
Unsuitable Habitat
Miles
SOURCE: Leitner, 2001
LWRP 2020 Plan EIR / 200481
Figure 4.4-6a
Mohave Ground Squirrel Habitat Assessment Area
Miles
SOURCE: Leitner, 2001
0
1
80 TH ST E
60 TH ST E
50 TH ST E
40 TH ST E
AVE H
AVE G
AVE F
AVE E
AVE D
90 TH ST E
LWRP 2020 Plan EIR / 200481
Figure 4.4-6b
Extent of Potential Mohave Ground Squirrel Habitat within the Eastern Agricultural Area
Low Suitability
Mohave Ground Squirrel Habitat
70 TH ST E
EDWARDS AIR FORCE BASE
100 TH ST E
Chapter 4 Environmental Setting, Impacts, and Mitigation
Literature surveys and reconnaissance-level field surveys conducted for the assessment area indicate that
the likelihood of encountering desert tortoise in the area is very slight. None of the regional management
plans include the assessment area within current desert tortoise range. Nonetheless, the area is within the
historic range of the threatened species. Since much of the area to be impacted by the proposed project is
currently undeveloped, it is possible that desert tortoise could be encountered during construction. Since
the species is a federally threatened species, this would be considered a significant impact of the project.
As such, the following mitigation measures would reduce the impact to less than significant levels.
Mitigation Measures
Alternatives 1, 2, 3, and 4
Mitigation Measure 4.4-7: Prior to working on the project, site managers and construction employees
working to clear work areas shall be educated as to the natural history, endangerment factors, and
appropriate protocol for dealing with tortoises encountered in and around the construction areas.
Mitigation Measure 4.4-8: If a tortoise is observed during construction, all construction shall be halted
in the immediate area. The USFWS and DFG must be immediately notified to determine necessary
actions.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-6: The construction of storage reservoirs for Alternatives 1 and 2 and the conversion of
previously undeveloped areas in the eastern and western agricultural area for each alternative
would result in the loss of shadscale scrub habitat.
The vegetation communities within the assessment area are not especially diverse but provide habitat for
a number of species with restricted ecological tolerances. The loss of these habitats on the site would
contribute to the local reduction in the overall carrying capacity of the project region for a variety of
common animals such as the Great Basin whiptail, the western meadowlark, the horned lark, the desert kit
fox, the antelope ground squirrel, and others. Predators such as red-tailed hawks and American kestrels
would also lose foraging habitat on the site.
The project would reduce the ability of the surrounding area to provide foraging habitat for raptors such
as burrowing owls, white-tailed kites, red-tailed hawks, northern harriers, and overwintering golden
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Chapter 4 Environmental Setting, Impacts, and Mitigation
eagles and may contribute to a reduction in the overall variety of species found in the surrounding area.
While the project would contribute to the loss of shadscale scrub and ruderal habitats in the area,
development of the site itself would not constitute a significant impact because of the large amount of
similar habitats available to wildlife on the adjacent EAFB. The loss of ruderal habitats within the
assessment area as a result of project implementation would not contribute to a reduction in the diversity
of wildlife species in the local project vicinity. Potential impacts to sensitive bird species that utilize
shadescale habitat for foraging, including those covered in the MBTA, are addressed in impact 4.4-3.
Mitigation Measure
Alternatives 1, 2, 3, and 4
None required.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-7: Construction of storage reservoirs for Alternatives 1 and 2 could impact Mojave
fringe-toed lizard habitat.
The Mojave fringe-toed lizard typically inhabits “blowsand” transported by wind or water. The extent of
blowsand habitat occupied by Mojave fringe-toed lizard at EAFB has not been determined with great
precision but appears to include historic dune areas on the western shoreline of Rosamond Dry Lake. The
sand sources for this area have not been entirely defined, thus it is not certain whether habitat
modifications in the storage reservoir area would reduce the sand sources for nearby blowsand habitats
that support the Mojave fringe-toed lizard. A reduction in water-transported sand is not anticipated as a
result of the proposed project because no major arroyos or washes flow through the assessment area.
Amargosa Creek and an unnamed blueline stream 0.5 mile north of the assessment area are considered to
contribute the most sand inputs in the proposed storage reservoir area and would not be modified or
otherwise affected by the proposed project. Because of the distance of the assessment area from the
identified Mojave fringe-toed lizard habitat (roughly one mile) and project avoidance of major waterborne sand sources, no impacts are anticipated to habitat.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
Mitigation Measure
Alternatives 1, 2, 3, and 4
No mitigation measures are necessary.
Significance After Mitigation
Less than significant.
_________________________
Impact 4.4-8: The elimination of effluent-induced overflows onto Rosamond Dry Lake for each
alternative would cause loss of mudflat habitat.
Habitat Description
The volume of effluent discharged to Amargosa Creek has caused Piute Ponds to consistently overflow
from approximately November through June each year since the early 1990s. This overflow creates a
mudflat on the dry lake during the winter and spring that is used for foraging by shore birds. The mudflat
habitat consists of shallow, nutrient-rich water spread out over a large area of the dry lakebed surface,
with no vegetation. The size of the mudflat habitat created by the overflow varies depending on the
overflow volume, but generally consists of a portion of the lakebed surface covering between 100 and
2,000 acres in the southern portion of the dry lake.81 The maximum extent (or seasonal average) of the
effluent-induced wetted area on the lakebed in the past is undetermined. The wetted area varies from year
to year and is generally non-existent from July through November. The Rosamond Dry Lake surface area
covers approximately 12,800 acres, fluctuating only a foot or two in elevation over the entire surface.
The southern edge nearest to the Piute Ponds outlet is approximately 2,273 feet amsl, with most of the
lakebed at 2,274 feet amsl.82
Large quantities of shorebirds have been observed on the effluent-induced mudflats. Sandpipers are
noted as the most numerous shorebirds that forage in the mudflats.83 It is assumed that the nutrient-rich
water overflowing C-Dike from Piute Ponds provides food for invertebrates in the mudflats on which the
81
Based on aerial photograph observations and effluent discharge volumes.
82
USGS, Lancaster, California, 1981.
83
Garrett, pers. comm.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
shorebirds feed. Shorebird abundance in this area appears to be directly correlated with the availability of
overflows from Piute Ponds. As an example, in the year 2000, overflows onto Rosamond Dry Lake
continued into April and more than 13,000 shorebirds (mostly Calidris sandpipers) were observed
foraging in the flooded mudflats on a single April day.84 In 2001, flows ceased near the end of March and
similar surveys in April identified no shorebird use of this area.85 Peak use of the overflow area generally
occurs during the spring migration (mid-March through early May). Bird migrations also occur in the fall
(early July through mid-September) although the overflows have only rarely occurred through the
summer and fall.
The mudflat habitat created by the effluent-induced overflow is shallow enough for wading birds.
Although Piute Ponds provides foraging habitat and cover for some species, the deep water prevents large
numbers of shorebird species from using the area. Shorebirds generally utilize the edges of the smaller
pools on the perimeter of the ponds.
A nesting population of snowy plover is known to exist near Piute Ponds.86 The mudflat foraging habitat
is well suited for the plover. Although the coastal population is listed as federally threatened, the
population near Piute Ponds is excluded from this designation.
Storm water runoff flows onto the dry lake during winter months from perimeter sheet flow and feeder
creeks including Littlerock Creek and Amargosa Creek. The amount of water reaching the lakebed each
year varies depending on the intermittent storms. Approximately once every two to three years, local
storm water runoff in Amargosa Creek is of sufficient volume to cause overflows through Piute Ponds
onto the dry lakebed. During storm events of this magnitude, water collected on the lakebed surface
greatly exceeds the volume contributed by the Piute Ponds effluent-induced overflows. This collected
water can take months to fully evaporate.
In the March of 2003, District No. 14 consultants and DFG staff observed the entire lakebed to be covered
with storm water runoff a few feet deep resulting from a storm the previous week. Thousands of ducks
and gulls were observed floating on the lake, with a few hundred shorebirds foraging on the lakebed
edges. From these observations, it appears that the storm flows that periodically inundate the lakebed
create a different type of habitat from the consistent, low volume, nutrient-rich, effluent-induced
84
Ibid.
85
Ibid.
86
WMPT, Draft West Mojave Plan, 2001.
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Chapter 4 Environmental Setting, Impacts, and Mitigation
overflows. The storm water runoff observed on the lakebed in March 2003 was too deep to create the
mudflat habitat used for foraging by wading shorebirds.
The creation of large agricultural areas could provide some year-round foraging opportunities for
migratory shorebirds that would serve to partially offset the loss of foraging opportunities associated with
the elimination of effluent-induced overflows onto Rosamond Dry Lake. Such foraging areas at Nebeker
Ranch have been observed to benefit numerous species of wading birds, waterfowl, raptors, and
shorebirds. However, because the benefits of these agricultural foraging areas are not fully known and
the replacement would be “out of kind,” the additional habitat value would not compensate for the loss of
the artificially induced Rosamond Dry Lake mudflats.
Summary
The elimination of effluent-induced overflows onto Rosamond Dry Lake would cause a loss of mudflat
foraging habitat that has been available for migrating waterfowl and native wildlife during the winter and
spring for approximately the last 10 years. No nesting habitat would be affected. The dry lakebed surface
would not be altered as a result of the project; only the water source would be eliminated. The dry
lakebed would revert to a more natural condition where the only surface water reaching the lake would be
from large rain storms.
Since no species listed as threatened or endangered on the state or federal Endangered Species Acts are
known to rely exclusively on this ephemeral, artificially created habitat, the elimination of the water
source would not result in the take or harassment of a protected species. Similarly, since the habitat does
not reflect a naturally induced wetland condition, and since it is not considered to be water of the US or a
wetland as delineated by the Corps, it is not considered to be a sensitive habitat under CEQA. No
conservation plans currently exist that identify or specifically call for the conservation of the habitat.
Elimination of the mudflat habitat would eliminate some foraging habitat to migrating shorebirds. This
could be viewed as a potentially significant impact of the project since impacting migratory birds is
considered a significant impact under CEQA and the MBTA. In addition, eliminating the mudflat habitat
created by the overflows during winter and spring months would substantially diminish foraging habitat
for the local shorebird species, which is a CEQA-identified threshold of significance.
Little is known about the extent to which the mudflat is used by migrating birds or its value to the Pacific
Flyway. The habitat is ephemeral and created within the last 10 to 20 years. Piute Ponds themselves
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Chapter 4 Environmental Setting, Impacts, and Mitigation
would not be altered and would still provide foraging habitat and nesting value for migratory birds.
Storm water runoff would continue to provide sporadic habitat for migratory birds on the dry lake during
wet years as has historically been the case. Nonetheless, the mudflat habitat created by the overflows
provides foraging opportunities for shorebirds that Piute Ponds does not provide.
It is the policy of District No. 14 to maintain Piute Ponds such that the value to migratory birds would not
diminish. The increased land application of effluent for agriculture would not add foraging habitat
suitable for shorebirds or water fowl. Eliminating the mudflat habitat would “substantially reduce the
habitat of…wildlife” and could “restrict the…range of a rare…animal” which are identified CEQA
thresholds of significance (CEQA Guidelines Appendix G, XVII Mandatory Findings of Significance).
Unless EAFB and RWQCB authorize overflows to provide habitat during the winter and spring months,
no measures are available to mitigate the significant impact short of creating a mudflat off of EAFB
property. This would not be feasible. Therefore the impact is considered significant and unavoidable.
Mitigation Measure
None available.
Significance After Mitigation
Significant, unavoidable.
No other mitigation measures have been identified that would mitigate the loss of the mudflat habitat.
Providing replacement mudflat habitat off site is not a viable option due to the particular attributes of the
existing habitat including the large surface area, the nutrient-rich qualities of the effluent, and the
subsurface soil conditions. These unique characteristics would be very difficult to duplicate elsewhere.
_________________________
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