2013-12-17_PERMIT FILE - C1992081 (13)

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Surface water Quality NGT will maintain water quality monitoring for compliance with the NPDES Permit for the loadout. Since 1986, there has not been an exceedence of an NPDES effluent parameter limit. Although the suite of parameters required to be monitored is reduced, iD5 levels should be a good indication of [he general pond water quaf icy. Surface ua ter quaf ity analyses presented in Tab 7, the Hydrologic Description, indicate [hat the existing water quality in Dry Creek in the immediate up- and downstream vicinity of the loadout is unsuitable for irrigation and only marginally suitable for livestock. the downstream surface water monitoring site chemistry (HGSD2 and HGSD3) is worse (higher TDS and some macroconstituents) largely due to the following. First, return floes from the flood irrigated fields in Section 22, TbN, R88w drain into Dry Creek below [he upper surface wafer monitoring site (HGSD7). Sec end, heavily salt-laden drainage from summer followed fields that are dry land farmed (Section 23, i6N, RBBw) enters into Dry Creek between the two stream monitoring sites. third, high TDS drainage from Stokes Gulch (white sal[ deposits visible along the drainage) enters Dry Creek just above stream monitoring site HGSD2. Last, high TDS seepage from the Lewis shale into Dry Creek may be • occurring along the channel between the up- and downgradien[ sites during certain periods of the year. The source of any elevated chemical constituents impounded in the sediment ponds would be from coal stockpile leachate in the surface runoff. Saturated paste extracts were run on samples of wadge and wolf Creek coal (unpublished data from core samples from the Yoas[ oroperty uh ich is likely to supply some of the coal stored at the loadout). The uatlge coal samples yielded paste conductivities ranging from 200 to 600 umhos/tm and the wolf Creek coal sample showed a paste conductivity of 800 umhos /cm, A review of Tables 7-3 and 7-4 in Tab 7, the Hydrologic Description, indicates that Dry Creek above and below [he loadout ranges in conductivity levels from 148D to 442D umhos/cm. TDS values measured at the outfall from NPDES Pond 002 are approximately tour times greater than those measured a[ the pond 001 outfall. the pri nctpal reasons for this are as follows. First, the drainage area of the watershed drained by Pond 002 is considerably larger than the ua[ersh etl drained by Pond 001. Second, Pond 001 is located along a ridge whereas Pond 002 is constructed Somewhat loner In a greaseuo od/sal [flat area along Dry Creek and thus receives runoff from areas with a higher salt yield potential. Finally, a comparison of the Pond 002 bottom elevation with the completion log for cell HGSD2, which 2 Nevised 04/18/94