SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

City of Stockton and County of San Joaquin Page 29 NPDES Permit CAS0083470 Response to Comments River are identified as Toxic Hot Spots because of diazinon and chlorpyrifos. Mosher Slough, Five- Mile Slough and the Calaveras River are also listed because of oxygen demand constituents. French Camp Slough is identified as a Toxic Hot Spot because of chlorpyrifos. The sources of these Toxic Hot Spots are identified as "Urban Runoff." Contaminates in storm water adversely affect lower tropic populations which are an essential food source for sensitive life stages of listed species. Phytoplankton production has decreased about one order of magnitude (Alpine and Cloem, 1992, Tropic interactions and direct physical effects control phytoplankton biomass and production in an estuary, Limnology and Oceanography 37:946-955)) while zooplankton production is down one to two orders of magnitude (Obrebski et al, 1992,Long term trends in zooplankton distribution and abundance in the Sacramento-San Joaquin estuary, Technical Report 32, Interagency Ecological Studies Program) in the San Joaquin River-Delta system. Studies conducted and/or funded by the Regional or State Water Boards have identified toxicity caused by contaminates contained in storm water runoff as a likely factor in these plankton decreases (Bailey et al., 1995, The effects of toxic contaminants in waters of the San Francisco Bay and Delta, Bay Delta Oversight Council; CDFG, 1994,Department of Fish and Game comments on key issues of the State Water Resources Control Board's June workshop for the review ofstandards for San Francisco Bay/Sacramento-San Joaquin Delta Estuary); De Vlaming V, bt al., 2000, Application of whole effluent toxicity test procedures to ambient water quality assessment, Environmental Toxicology Chemistry 19:42-63). Response: Comment noted. Tentative Order's findings and Fact Sheet recognize that Stockton area waterways have significant water quality impairment. 2. Comment: (DK Comment 2(a)) The Permit Is Not Protective Of Species Listed Pursuant To State And Federal Endangered Species Acts. The Delta, San Joaquin River, Calaveras River and local waterways are habitat and migration corridors for a number species protected under federal and state endangered species acts. Storm water discharges occur during spawning or sensitive life stages for these species. Species include: Central Valley spring-run Chinook salmon(Oncorhynchus tshawytscha - federal and state listed as threatened); Central Valley steelhead (Oncorhynchus mykiss -federal listed as threatened); Delta smelt(Hypomesus transpacifcus- federal and state listed as threatened); Sacramento splittail (Pogonichthys macrolepidotus - federal listed as threatened, California species of concern). Depending upon water-year type and operation of the state and federal project pumps, other listed species can be drawn into these waterways including winter-run Chinook salmon (Oncorhynchus tshawytscha - federal and state listed as endangered). Additionally, fall/late-fall-run Chinook salmon have been proposed to be listed as threatened and are California species of concern. Green sturgeon (Acipenser medirostris) are being evaluated for listing and is a California species of concern. The longfin smelt(Spirinchus thaleichths), hardhead(Mylopharodon conocephalus) and Sacramento perch(Archoplites interruptus) are identified as California species of concern. The National Marine Fisheries Service (NMFS) has identified the Delta and its tributaries, including local waterways as "Critical Habitat." 65 Fed. Reg. 7764-7787 16 Feb 2000 (designating critical