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Draft Supplemental Environmental Impact Report Page IV.F-9 Forward Inc. Landfill 2014 Expansion Project — Chinook Salmon Sacramento winter-run chinook salmon (Oncorhynchus tshawytscha) is a federal and state-listed Endangered species. Sacramento spring-run chinook salmon (Oncorhynchus tshawytscha) is a federal and state Threatened Species, and Central Valley fall/late-fall chinook salmon (Oncorhynchus tshawytscha) is a National Marine Fisheries Service (NMFS) Species of Concern and a California Species of Special Concern (CDFG 2011a). Because both branches of the South Fork of Littlejohn's Creek are used for conveyance of irrigation water, the flows are highly variable and do not correspond to the natural hydroperiod for streams (i.e. wet winters/ dry summers)in the San Joaquin County area. The National -� Marine Fisheries Service (NMFS)has stated that Chinook salmon could be present in Littlejohn's Creek at a nearby project site in the fall and winter months,but acknowledges that their presence would be unlikely (Bein Frost and Associates 1999). _ Chinook salmon are not known to spawn in Littlejohn's Creek,however, individuals of the species attempted to migrate upstream into the North Branch of the South Fork of Littlejohn's Creek in 2003 (pers. comm. Sydney Temple,Questa Engineering Corporation). This occurred in — the late fall, immediately after restoration work in the North Branch was completed and the new channel was opened. A flow gate was opened upstream by the Central San Joaquin Water Conservation District to convey water to downstream agricultural fields and this sent a — sediment plume downstream. Approximately six to eight Chinook salmon were attracted from the San Joaquin River into the channel, and once flows were shut off, perished in the channel due to the lack of sufficient flows to sustain these animals. This occurrence was reported to CDFW, and reportedly occurred in several other irrigation channels in the County over the same brief period in fall 2003, and is considered to have been an isolated event (pers. comm. Sydney Temple,Questa Engineering Corporation). _ The South Branch of the South Fork of Littlejohn's Creek has less flow than the North Branch, and is dry during most of the year(pers. comm. Sydney Temple,Questa Engineering Corporation). Restoration of this branch of the creek will provide habitat for some semi-aquatic and riparian wildlife species,but is not expected to provide suitable habitat for salmonids due to low flows and the highly modified flow regime. Potential impacts to this species are evaluated later in this section (see Potential Impacts and Mitigation Measures, below) Giant Garter Snake The giant garter snake(Thamnophis couchi gigas)is a federally and state-listed Threatened species (CDFG 2011b). Giant garter snake(GGS)is a large dull colored snake endemic to the valley floor wetlands of Sacramento and San Joaquin Valleys of California (USFWS 1999b). Giant garter snakes are highly aquatic and inhabit freshwater marshes, low-gradient streams, — drainage canals, and irrigation ditches, especially those associated with rice farming from Butte County to Fresno County. Currently, 13 populations of giant garter snakes are recognized, which correspond to historic flood plains and tributary streams throughout the Central Valley. — San Joaquin County is one of the 11 Counties in the Central Valley where the giant garter snake is still presumed to occur. The abundance and distribution of giant garter snakes has not changed significantly since the time of federal listing: many populations north of Stockton remain stable, while the two known populations south of Stockton remain small, fragmented, and unstable and are probably decreasing (USFWS 2006). The closest records of giant garter snake to the project site are south of Stockton, approximately 8 miles north and east of the project site,within the East Stockton--Diverting Canal and Duck Creek(CNDDB 2012). In