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This seems contradictory. [t is our understanding that pumping of water from pits is <br />something Colowyo wishes to be allowed to do under its pond revision currently being <br />reviewed by our offices. We do not understand why Colowyo would state that "No <br />pumping is involved." <br />3. With regard to Colowyo requesting that the words "process water" be removed from the <br />CDPS permit, we again refer WQCD to its own memo of April l7, 1996 (attached) <br />regarding this issue. <br />4. On Page 2 of its September 30, 1997 memo, in Section "S.N.A.3., Chemicals Used, <br />Rationale Page 3", Colowyo incorrectly restated the sentence from that section of the <br />Rationale document. We believe the language in the Rationale document should remain <br />as proposed by WQCD. <br />Under Section "6.N.B., Wastewater Treatment Description, Rationale Page 4," (Pages <br />2 and 3 of the September 30 memo), Colowyo again wishes the Rationale be reworded <br />so that water that is pumped from the Washbay pond to the Work Area/Warehouse pond <br />is not referred to as being pumped. We believe the original language of the Rationale <br />document should remain. <br />6. Colowyo states on page 3 of its September 30 memo that the Rationale document should <br />be reworded to read "The ponds are designed and treat to contain the volume of a <br />l0-year, 24-hour storm and/or snowmelt event ("containment mode")". <br />We reiterate that Colowyo's ponds aze currently designed to pass and treat the 10-year, <br />24-hour precipitation event. Cotowyo's ponds are not currently designed to contain the <br />10-year, 24-hour event. Further, discharges through the ponds primary (10-year, <br />24-hour event) spillways are designed to meet the settleable solids limitations, but <br />discharges through manually-operated dewatering tubes are not designed to meet any <br />limitations. It is therefore imperative that the CDPS permit require that every discharge <br />through manually-operated dewatering tubes be sampled, to demonstrate that the <br />discharge meets the settleable solids, or TSS and total iron, limitations as appropriate. <br />On page 3 of its September 30 memo, Colowyo implies that its exceedances were due <br />to abnormally high levels of snowfall and rainfall, and warm weather. However, burden <br />of proof and alternate limitations are specifically set to account for storm event size. We <br />believe Colowyo's exceedances were instead related to manual dewatering of ponds <br />currently classified as automatic dewatering ponds. <br />Colowyo indicates that "it is possible that these exceedances would have been the same, <br />or perhaps even higher had the ponds been operated in the treatment mode...". They <br />further blame aquatic vegetation in the ponds as a reason for some of the exceedances. <br />Colowyo, however, does not provide proof of these scenarios. In addition, failure by an <br />operator to maintain its sediment ponds (removal of vegetation could be considered a <br />main[enance item if the vegetation interferes with a pond's operation) could be a <br />