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Trapper Mining, Inc. WWTF Water Quality Assessment CO-0032115
<br />Horse Gulch, West Horse Gulch, West Flume Gulch, Middle Flume Gulch, East Middle Flume.
<br />Gulch, East Flume Gulch, and Deal Gulch have a ]ow flow of zero.
<br />The Trapper Mining, Inc. W WTF is the sole known point source contributor to Johnson Gulch, No
<br />Name Gulch, Far East Buzzard Gulch, Coyote Gulch, Ute Gulch, Middle Pyeatt Gulch, East Pyeatt
<br />Gulch, West Pyeatt Gulch, Deer Gulch, Grouse Gulch, Sage Gulch, Oak Gulch, Horse Gulch, West
<br />Horse Gulch, West Flume Gulch,.Middle Flume Gulch, East Middle Flume Gulch, East Flume
<br />Gulch, and Deal Gulch. No other point sources were identified as dischazgers to these waters
<br />upstream or downstream except one minima] dischazger with no pollutants in common. Thus, the
<br />findings of this assessment indicate that there is no dilution, no other sources of pollutants of
<br />concern, and that assimilative capacities are equal tothe in-stream standards applied to the Trapper
<br />Mining, Ina WWTF effluent dischazge.
<br />Information used in this assessment includes data gathered from the Trapper Mining, Ina W WTF,
<br />the WQCD, the Colorado Division of Water Resources (DWR), the U.S. Environmental Protection
<br />Agency (EPA), the U.S. Census Bureau, and the U.S. Geological Survey (USGS). The data used in
<br />the assessment consist of the best information available at the time of preparation of this WQA
<br />package.
<br />II. Water Quality
<br />The Trapper Mining,. Inc. WWTF discharges to the Water Body Identification (WBID) stream
<br />segment 3b, which is composed of "Mainstem of Johnson Gulch, Pyeatt Gulch, Ute Gulch, Castor
<br />Gulch, No Name Gulch, Flume Gulch, Buzzazd Gulch, Coyote Gulch, and Deal Gulch, Horse Gulch,
<br />Ben Morgan Creek, Boxelder Gulch, Collom Gulch, Hale Gulch and Jubb Creek, including all
<br />tributaries from their sources to their mouths." Stream segment 3b is classified for Warm Water
<br />Aquatic Life Class 2, Class lb Potential Primary Contact Recreation, and Agriculture.
<br />Numeric standards aze developed on abasin-specific basis and are adopted for particulaz stream
<br />segments by the Water Quality Control Commission. To simplify the listing ofthesegment-specific
<br />standards, many of the aquatic life standazds are contained in a table at the beginning of each chapter
<br />of the regulations. The standards in Table A-2 have been assigned to stream segment 3b in
<br />accordance with the Classifications and Numeric Standards for Lower Colorado River Basin.
<br />Ambient Water Oualsty
<br />The WQCD evaluates ambient water quality based on a variety of statistical methods as prescribed in
<br />Section 31.8(2)(a)(i) and 31.8(2)(b)(i)(B) of the Colorado Department of Public Health and
<br />Environment Water Quality Control Commission Regulation No. 31. The ambient water qualitywas
<br />not assessed for Johnson Gulch, No Name Gulch, Faz East Buzzard Gulch, Coyote Gulch, Ute
<br />Gulch, Middle Pyeatt Gulch, East Pyeatt Gulch, West Pyeatt Gulch, Deer Gulch, Grouse Gulch, Sage
<br />Gulch, Oak Gulch, Horse Gulch, West Horse Gulch, West Flume Gulch, Middle Flume Gulch, East
<br />Middle Flume Gulch, East Flume Gulch, and Deal Gulch becausethe backgound in-stream ]ow flow
<br />condition is zero, and because no ambient water quality data are available for these waters upstream
<br />of the Trapper Mining, Inc. W WTF dischazge.
<br />Appendix A Page 3 of 8 Draft
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