The California Department of Transportation (Permittee) proposes the rehabilitation and reconstruction of the existing pavement on the I-680 mainline and ramps from the Koopman undercrossing (PM 12.4) near the Town of Sunol in Alameda County to the Alcosta Boulevard overcrossing (PM 21.9) in the City of San Ramon, Contra Costa County. The Project will also improve traffic safety by upgrading and/or replacing the metal beam guardrail (MBGR) with concrete barriers. Additionally, the Project involves several components, including resurfacing and restoring I-680 mainline and ramps; replacing approach slabs; repairing or replacing drainage systems, including culverts, down drains, inlets, curbs, edge drains, dikes, and slope correction; replacing or upgrading MBGR, concrete barriers, guardrail-bridge connections, and end treatments. The Project will also include replacing loop detectors, upgrading roadway signs, raising overhead sign structures, installing shoulder backing material, and implementing American with Disability Act (ADA) requirements as needed. The Project length consists of eight segments with existing surface pavement that is a combination of asphalt concrete (AC) or Portland cement concrete (PCC).
The Biological Study Area (BSA) consists of 381.70 acres, which consists of 216 acres of paved surfaces, Impacts to Alameda whipsnake habitat include temporary impacts to 3.77 acres of Alameda whipsnake suitable habitat and permanent impacts to 1.41 acres of suitable Alameda whipsnake habitat. The project is expected to result in incidental take of Alameda whipsnake aka Alameda striped racer, designated as a threatened species under CESA. The ITP referenced above as issued by CDFW authorizes incidental take of species listed under CESA that may occur as a result of Project implementation.
The areas where authorized take of the Covered Species is expected to occur are within a 381.70-acre footprint, within the biological study area (BSA), 216 acres are paved surfaces and 44 acres are suitable Covered Species habitat. The Project is expected to impact a total of 1.15 acres of habitat for the Covered Species. Impacts to Alameda whipsnake include 0.17 acres of permanent impacts and 0.98 acres of temporary impacts to foraging and dispersal habitat. Impacts to California tiger salamander include 0.17 acres of permanent impacts and 0.98 acres of temporary impacts to foraging and dispersal.