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Comments Submitted by Denver Water <br />August 20, 2010 <br />location map, revised site map, and revised water balance that satisfies the application <br />requirements. When examining the WQA and permit documents, it appears that <br />assessment decisions were made by the WQCD without the benefit of contemporaneously <br />filed information from the applicant that shows waste rock, mine pool, and other pollutant <br />loadings to Ralston Creek. The permit application should also indicate that the remedial <br />groundwater treatment system being implemented is significantly different than the <br />previous WWTF associated with existing permit CO-0001244. Please see the diagram in <br />Attachment B identifying these potential pollutant sources. <br />Stricter Uranium Effluent Limits and New Limits for Gross Alpha and Gross <br />Beta <br />Ralston Reservoir is the potable water supply, as stated above. The location of the <br />mine's pollutant sources is such that the travel time to potable water intakes is short. It is <br />certain that uranium, other radionuclides, and metals are accumulating within the reservoir <br />and that there is potential to impact water treatment plant residual management. The 30 <br />pg/L in-stream standard listed in Table A-3 for uranium should be pre-empted by the health <br />concerns documented in Regulation No. 31 Basic Standards and Methodologies for Surface <br />Water at paragraph 31.48 and set at 16.8 pg/L, or stricter. The value of 16.8 pg/I was <br />established in the most recent amendment to Regulation No. 31. The value should be <br />reduced to a stricter level if a TMDL assessment inclusive of all pollutant sources warrants a <br />lower level to attain water quality standards. <br />Additionally, in the table of effluent limits for outfall 001A, the frequency of <br />monitoring for Radium 228, both dissolved and total, needs to be coordinated on the same <br />dates and frequencies as Radium 226 so that combined radium can be calculated just as <br />frequently. The units for Radium 226, both dissolved and total are omitted. <br />An effluent limitation for Gross Alpha and Gross Beta is appropriate and is missing. <br />Under 5 CCR 1002-31.14(4), the WQCD may adopt a numeric standard if necessary: <br />Where no statewide or site-specific numeric standard exists for a <br />constituent of concern, the Division may establish effluent limitations or <br />other permit conditions for such constituent if necessary to comply with the <br />narrative standards in section 31.11(1). Such effluent limitations shall be <br />developed in a manner consistent with the Commission's methodology for <br />establishing numeric water quality standards and, if applicable, shall be <br />consistent with the criteria contained in table I, II and III of this regulation. In <br />such circumstances, upon the request of any interested person, the <br />Page 6 of 8