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Table A -6 <br />Ambient Water Quality for the Dolores River <br />Parameter <br />Number <br />of <br />Samples <br />1 Sth <br />Percentile <br />SOth <br />Percentile <br />85th <br />Percentile <br />Mean <br />Maximum <br />Chronic <br />Stream <br />Standard <br />Notes <br />DO (mg/1) <br />107 <br />7.9 <br />9.5 <br />12 <br />9.8 <br />13 <br />5 <br />pH (su) <br />108 <br />7.6 <br />8 <br />8.3 <br />8 <br />8.6 <br />6.5 -9 <br />E. coli (# /100 ml) <br />4 <br />11 <br />22 <br />62 <br />24 <br />85 <br />126 <br />1 <br />NH Tot (mg/1) <br />112 <br />0 <br />0.12 <br />0.2 <br />0.12 <br />0.46 <br />TVS <br />2 <br />As, TR (µg./1) <br />7 <br />0 <br />0 <br />0 <br />0 <br />0 <br />7.6 <br />2 <br />As, Dis (µg/1)* <br />2 <br />0 <br />0 <br />0 <br />0 <br />0 <br />340 <br />2 <br />Cd, Dis (µg/1) <br />47 <br />0 <br />0 <br />0 <br />0.2 <br />4.9 <br />3.80 <br />2 <br />Cr +6, Dis (µg/1) <br />26 <br />0 <br />0 <br />0 <br />0 <br />0 <br />11 <br />2 <br />Cu, Dis (µg/1) <br />34 <br />0 <br />5.5 <br />14 <br />6.7 <br />24 <br />16 <br />2 <br />Fe, TR (µg/1) <br />74 <br />290 <br />830 <br />4800 <br />2599 <br />26800 <br />1000 <br />Pb, Dis (µg/1) <br />35 <br />0 <br />0 <br />0 <br />0 <br />0 <br />5.40 <br />2 <br />Mn, Dis (1.1g/1) <br />59 <br />0 <br />9 <br />62 <br />26 <br />120 <br />2088 <br />2 <br />Hg, Tot (µg/1) <br />10 <br />0 <br />0 <br />0 <br />0 <br />0 <br />0.01 <br />2 <br />Se, Dis (41) <br />11 <br />0 <br />0 <br />3 <br />1.5 <br />8.9 <br />4.6 <br />2 <br />Ag, Dis (µg/1) <br />25 <br />0 <br />0 <br />0.08 <br />0.033 <br />0.21 <br />1.1 <br />2 <br />U, Dis (µg/1) <br />48 <br />0 <br />3.1 <br />6 <br />3.6 <br />34 <br />3274 <br />2 <br />Zn, Dis (µg/1) <br />112 <br />0 <br />0 <br />22 <br />15 <br />340 <br />215 <br />2 <br />B, Tot (mg/1) <br />49 <br />0 <br />0.11 <br />0.27 <br />2.2 <br />100 <br />0.75 <br />2 <br />Radium 226 +228 (pCi/l) <br />35 <br />0.32 <br />0.9 <br />1.9 <br />3.4 <br />44 <br />5 <br />3 <br />Hardness as Ca + mg (mg/1) <br />4 <br />158 <br />200 <br />248 <br />203 <br />270 <br />NA <br />Note 1: The calculated mean is the geometric mean. No e that for summarization purposes, the value of one was used where there was no detectable amount <br />because the geometric mean cannot be calculated using a value equal to zero. <br />Note 2: When sample results were below detection levels, the value of zero was used in accordance with the Division's standard approach for suuu,rarization <br />and averaging purposes. <br />Note 3: The ambient water quality is based on sample results for Radium 226 only. <br />*The value for dissolved arsenic is the acute stream standard. <br />Cotter Corporation Water Quality Assessment <br />C00036251 <br />V. Facility Information and Pollutants Evaluated <br />Facility Information <br />JD -7 Mine- Outfall 001 <br />The JD -7 Mine's WWTF is located at in the SE 1/4 of S16, T46N, R17W; approximately 15 miles <br />West ofNaturita, CO 81422 at latitude 38° 14" 36' North and longitude 108° 45" 01' West in <br />Montrose County. The current design capacity of the facility is 0.20 MGD (0.31 cfs). <br />Wastewater treatment is accomplished at JD -7 mine using chemical coagulation and precipitation <br />with two non - aerated lagoons in series. The technical analyses that follow include assessments of <br />the assimilative capacity based on this design capacity. <br />Appendix A (WQA v 7.0) <br />Page 16 of 23 Last Revised 06/10/10 /AO <br />