Indicator Bacteria Water Quality Objectives Protective of Beneficial Uses in the Eastern Sierra Nevada Mountains.

Protection of water quality in California rests with the State Water Resources Control Board and nine Regional Water Quality Control Boards. The Lahontan Regional Water Quality Control Board (Water Board) develops and implements Water Quality Objectives (WQO) based on natural water quality, actual and potential beneficial uses, and water quality problems associated with human activities, in an area that extends from the Oregon border to the northern Mojave Desert and includes all of California east of the Sierra Nevada crest (eastern Sierras). The Lahontan Region includes over 700 lakes, 3,170 miles of streams and 15 major watersheds and two federally-designated Outstanding National Resource Water—Lake Tahoe and Mono Lake. The natural quality of most high elevation waters, which are derived from snowmelt, is assumed to be very good or excellent. Water quality problems in the Lahontan Region are largely related to nonpoint sources (including livestock grazing). Much of the Lahontan Region is in public ownership, with land use controlled by agencies such as the U.S. Forest Service and the Bureau of Land Management, both of which manage grazing allotments on public lands. Recreational use (swimming, day hiking, backpacking, and fishing) of the eastern Sierras is very high. As a result, the Water Board has a promulgated a highly protective WQO for fecal coliform, beginning in 1975, The Water Board is developing a tiered WQO that considers (A) recreational beneficial uses (REC) to protect human health based on are intentional consumption of untreated or partially treated water (ex. backpackers, dispersed camping, hikers) and (B) other applicable beneficial uses. Regulatory constraints include Federal antidegradation statutes, and California non-degradation policy for high quality waters. The Water Board has analyzed over 2500 fecal coliform and E. coli samples in over 100 locations in the eastern Sierras from 2008 through 2013, as well as over 2400 historic fecal coliform samples prior to 2008. A binomial model will be used for development of proposed WQOs for indicator bacteria E. coli and fecal coliform base on analysis of this data, and results will be presented.