Interstate 10/Avenue 50 New Interchange NES Natural Environment Study Riverside County, CA District 08-RIV-10- PM R62.3/R63.7 EA Number 08-452100 Caltrans Project Number 0800000721 November 2016 Summary Summary This Natural Environment Study (NES) has been prepared to support the National Environmental Policy Act (NEPA) and California Environmental Quality Act (CEQA) documentation for the proposed Interstate (I) 10/Avenue 50 New Interchange Project (hereinafter referred to as the proposed project) located in the City of Coachella in Riverside County, California. The proposed project is the creation of a new interchange along I-10 east of the existing Dillon Road interchange (Postmile [PM] R62.3 to R63.7). This NES includes information on the biological resources in the Biological Study Area (BSA) for the proposed project and meets the State of California Department of Transportation (Caltrans) NES guidelines (Caltrans 2009). This information has been reported in accordance with accepted scientific and technical standards that are consistent with the requirements of the U.S. Fish and Wildlife Service (USFWS), the California Department of Fish and Wildlife (CDFW), and Caltrans. The BSA for the proposed project includes the proposed impact area plus a 500-foot buffer area. The following vegetation types and other areas occur in the BSA: desert annual grassland, white bursage scrub, cheesebush scrub, allscale scrub, creosote bush scrub, creosote bush – white bur sage scrub, Mojave desert wash scrub, wand holdback (unique stand), disturbed/unvegetated, and developed. The BSA is currently open space and provides moderate to high quality desert scrub habitat for wildlife species. Alluvial washes, including Smokey Gulch, and culverts passing beneath the I-10 in the BSA currently provide wildlife crossings that connect open space located north and south of I-10. Two Build Alternatives are evaluated in this NES. Direct permanent and temporary impacts of Alternative 3 and Alternative 4 are listed in Table ES-1 and Table ES-2. Alternative 3 would impact approximately 96.61 acres (13.48 acres permanent, 83.13 acres temporary) of desert scrub vegetation and approximately 17.48 acres of other areas (disturbed/unvegetated and developed). Alternative 4 would impact approximately 96.86 acres (12.80 acres permanent, 84.06 acres temporary) of desert scrub vegetation and approximately 17.48 acres of other areas (disturbed/unvegetated and developed). One special status vegetation type—Mojave desert wash scrub— would be impacted; Alternative 3 would impact 5.50 acres and Alternative 4 would impact 5.53 acres. Both Alternatives 3 and 4 would impact 1.18 acre of RWQCB/CDFW waters and 0.21 acre of RWQCB/CDFW isolated waters; waters do not qualify to be under the jurisdiction of the USACE. Mitigation for impacts on Mojave desert wash scrub and RWQCB/CDFW jurisdiction will include obtaining I-10/Avenue 50 New Interchange Project v Summary appropriate permits from the Regional Water Quality Control Board (RWQCB), and the CDFW. Potential mitigation options may include (1) removal of exotic species; (2) payment to a mitigation bank or regional riparian enhancement program; and/or (3) restoration of Mojave desert wash scrub either on site or off site at a ratio of no less than 1:1, determined through consultation with the RWQCB, and the CDFW. Table ES-1 Vegetation Types and Other Areas That Would Be Impacted by the Alternative 3 Permanent Temporary Total Project Project Project Vegetation Type and Other Existing Impact Impact Impact Areas (Acres) (Acres) (Acres) (Acres) Desert annual grassland 106.93 6.36 35.30 41.66 White bursage scrub 5.75 0.40 2.72 3.12 Cheesebush scrub 24.74 0.20 2.05 2.25 Allscale Scrub 32.05 1.98 20.12 22.10 Creosote bush scrub 75.93 0.77 9.82 10.59 Creosote bush – white bur sage 123.70 2.48 8.91 11.39 scrub Mojave desert wash scrub 47.10 1.29 4.21 5.50 Wand holdback (unique stand) 6.10 0.00 0.00 0.00 Disturbed/unvegetated 16.43 0.38 3.68 4.06 Developed 20.22 3.55 9.88 13.43 Total 458.95 17.41 96.69 114.10 Table ES-2 Vegetation Types and Other Areas That Would Be Impacted by the Alternative 4 Permanent Temporary Total Project Project Project Vegetation Type and Other Existing Impact Impact Impact Areas (Acres) (Acres) (Acres) (Acres) Desert annual grassland 106.93 5.69 36.01 41.70 White bursage scrub 5.75 0.40 2.72 3.12 Cheesebush scrub 24.74 0.20 2.06 2.26 Allscale scrub 32.05 1.95 20.16 22.11 Creosote bush scrub 75.93 0.77 9.82 10.59 Creosote bush – white bur sage 123.70 2.51 9.04 11.55 scrub Mojave desert wash scrub 47.10 1.28 4.25 5.53 Wand holdback (unique stand) 6.10 0.00 0.00 0.00 Disturbed/unvegetated 16.43 0.39 3.66 4.05 Developed 20.22 2.96 10.47 13.43 Total 458.95 16.15 98.19 114.34 I-10/Avenue 50 New Interchange Project vi Summary The BSA for the project is located within the Coachella Valley Multiple Species Habitat Conservation Plan (CV MSHCP) area, but is not located within a Conservation Area. The CV MSHCP provides authorization under the Federal and California Endangered Species Acts that allows the “take” of Covered Species, including loss of their habitat, if the project is consistent with MSHCP requirements. As participating jurisdictions in the CV MSHCP, Caltrans will be required to comply with all applicable reserve assembly measures; however, because the project is not located within or adjacent to a Conservation Area, no avoidance, minimization, and mitigation measures would be applicable other than compliance with the Migratory Bird Treaty Act (MBTA); and compliance with the California Fish and Game Code. Focused surveys were previously conducted in 2001 and 2006 for several special status plant and wildlife species; the results of these surveys are incorporated into this report. Vegetation mapping was updated in 2013. Special Status Plant Species: Six individuals of Mecca-aster (Xylorhiza cognate) were observed in the BSA during spring botanical surveys in 2006. This location would be impacted by both alternatives. However, Mecca-aster is a species Covered under the CV MSHCP; therefore, no mitigation is required. No other special status plant species are expected to occur in the BSA. Special Status Reptiles: Sign of desert tortoise (Gopherus agassizii) was observed outside the outermost Zone of Influence (ZOI) transect during the 2001 focused surveys and a potential burrow was observed during the 2006 focused surveys. The desert tortoise is considered absent from the BSA at this time because they were not observed within the ZOI. Additionally, desert tortoise is a species Covered under the CV MSHCP; therefore, no mitigation would be required. No flat-tailed horned lizard (Phrynosoma mcallii) were observed in the BSA during the 2001 or 2006 focused surveys. Special Status Bird Species: Five active burrowing owl (Athene cunicularia) burrows were observed in the BSA; both alternatives would impact one burrow location. It should be noted that active burrow locations are expected to change with time. A pre-construction survey would be required to detect any active burrows at the time of construction. Sections 3503, 3503.5, and 3513 of the California Fish and Game Code prohibit impacts on any active raptor nest. This includes the burrowing owl, as well as the prairie falcon (Falco mexicanus) and any common raptor species such as the American kestrel (Falco sparverius). If vegetation clearing would occur during the raptor nesting season (February 1 to June 30; February 1 to August 31 for I-10/Avenue 50 New Interchange Project vii Summary burrowing owl), a pre-construction survey for nesting raptors would be required. Any active nest or burrow found during survey efforts will be protected until nesting activity has ended to ensure compliance with the California Fish and Game Code. Another raptor potentially foraging in the area is ferruginous hawk (Buteo regalis). Other special status bird species observed or with potential to occur include loggerhead shrike (Lanius ludovicianus), black-tailed gnatcatcher (Polioptila melanura), Crissal thrasher (Toxostoma crissale), and Le Conte’s thrasher (Toxostoma lecontei). If vegetation clearing would occur during the bird nesting season (February 1 to August 31), a pre-construction survey for nesting birds would be required to ensure compliance with the MBTA. Special Status Mammal Species: A focused trapping program for the Palm Springs pocket mouse (Perognathus longimembris bangsi) was conducted in 2001 and confirmed the presence of this species in the BSA. However, Palm Springs pocket mouse is a species Covered under the CV MSHCP; therefore, no mitigation is required. Focused surveys for the Palm Springs [Coachella Valley] round-tailed ground squirrel (Xerospermophilus tereticaudus var. chlorus) conducted in 2001 and 2006 determined that this species is absent from the BSA. Other special status mammal species with potential to occur include pallid San Diego pocket mouse (Chaetodipus fallax pallidus) and American badger (Taxidea taxus); impacts on these species would be considered less than substantial. Pallid bat (Antrozous pallidus), western mastiff bat (Eumops perotis californicus), and pocketed free-tailed bat (Nyctinomops femorosaccus) have potential to forage and roost in the BSA. A pre- construction passive acoustical survey for roosting bats will be required prior to construction to ensure that an active roost is not impacted. Construction activities will be limited to daylight hours (to the extent practicable) and permanent night lighting will be directed away from open space areas in order to avoid indirect effects on nocturnal species as a result of night lighting.