Abstract |
Section 303(d)(1)(C) of the federal Clean Water Act and the U.S. Environmental Protection Agencys (EPA) implementing regulations (40 CFR Part 130) require the establishment of a Total Maximum Daily Load (TMDL) for achieving water quality standards when a waterbody is water quality-limited (i.e. impaired). A TMDL identifies the pollutant reductions and controls needed to meet state water quality standards. The focus of the TMDL is reducing pollutants entering a waterbody to a level - or a prescribed load - that fully supports the designated uses of the waterbody. In the case of Granite Creek, the parameters of concern are sediment and turbidity from nonpoint sources. The means to evaluate success and address nonpoint source water quality issues after the TMDL is completed include a combination of best management practices and monitoring. Every two years since the mid-1980's, the Alaska Department of Environmental Conservation (ADEC) has submitted a list of waters to the EPA that persistently exceed water quality standards and/or exhibit impairment of uses. Beginning with the 1996 Section 303(d) list, the Alaska Department of Environmental Conservation (ADEC) identified Granite Creek as a Tier I impaired, or water quality-limited water, due to excess turbidity and sediment introduced from industrial gravel mining. Sources of impact are listed exclusively as nonpoint sources. Granite Creek is among 58 impaired waterbodies statewide on Alaskas current federally approved Section 303(d) list. |