Laserfiche WebLink
~~ <br />Michael G. Alrtvilla <br />Seneca Coal Company <br />Page 2 <br />August 13, 1999 <br /> <br />3. The Division recommends using the Basic Standards and Methodologies for Surface <br />Water for comparison with surface water samples from the Seneca II Mine. There are two <br />different stream segment descriptions with corresponding standards that would apply to the <br />Seneca II Mine. These include discharges to: Grassy Creek, Segment 12 of the Yampa River <br />Sub-basin of the Upper Colorado River Basin, and to Fish Creek, Segment 136 of the Yampa <br />River Sub-basin of the Upper Colorado River Basin. This information was verified in Section III <br />of SCC's Colorado Discharge Permit System permit. Upon review of the Classifications and <br />Numeric Standards for the Upper Colorado River Basin, it does not appear that any of the <br />applicable CDPHE surface water quality standards were exceeded for the constituents listed in <br />Table l0 of the 1998 AHR. In Table 9, SCC presents surface water agricultural standards from <br />various references. It is commendable [hat SCC has attempted to identify applicable water quality <br />standards for comparison with analytical results and for the sake of discussion. However, please <br />check the standards referenced in Table 9 for accuracy and applicability. It may be appropriate to <br />rename Table 9 as "Use-Suitability Standards". If deemed appropriate, please revise Table 10 to <br />ensure that appropriate CDPHE standards are listed for comparison with analytical results. <br />4. The PHC predictions contained in the permit document for TDS concentrations on Fish <br />Creek are consistent with the observed data collected at monitoring site SW-S2-13 during 1998. <br />Observed TDS concentrations for 1998 on Grassy Creek were slightly elevated above the <br />predicted TDS concentrations for monitoring site SW-S2-2. Please provide any available <br />information on the source of the elevated TDS levels on Grassy Creek. <br />If you have any questions concerning the Division's review of the 1998 AHR, please contact me. <br />Sincerely, <br />M, >a G~"~ <br />Michael P. Boulay <br />Environmental Protection Specialist <br />