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I • Grassy Creek; and Site 3, which monitors discharges from pre-SMCRA <br />mining areas and is located adjacent to Site 2. <br />- Surface Water Site SW-SZ-1 (SSGI). This site monitors Grassy Creek <br />upstream of mining by the Seneca II Mine. It was dry in July through <br />October of this year. Review of the TDS plot indicates a slightly <br />increasing trend. <br />- NPDES Discharge Point 003 (NPDES3). Hydrographs presented in Appendix <br />D show that flow has increased at this site since September 18, 1984, <br />when operation of the truck wash system began. Water is siphoned from <br />the Wadge Impoundment (NPDES 002) into a holding pond. Overflow from <br />the holding pond is diverted into the shop ditch, which flows into NPDES <br />003. Water is pumped from the holding pond to the wash rack, drains <br />into a settling pond, and then into the same shop ditch. This operation <br />has increased the flow at NPDES 003 while decreasing the flow at NPDES <br />002. Two other events that affected the long-term hydrograph include <br />the diversion away from NPDES 003 of runoff from an inactive fly ash pit <br />(operated by the Hayden Station power plant) in October, 1980; and the <br />diversion away from NPDES 003 of runoff contained in the Northwest <br />Diversion Ditch (see the Seneca II Permit Application, Exhibit 7-7, <br />Surface Water Hydrology Map and also the 1982 Seneca II AHR) in April, <br />1982. Finally, discharge volumes at the 003 site have been affected by <br />the reduction in diameter of the discharge culvert (36 inches to 6 <br />inches) that occurred on July 19, 1988. This year's average flow value, <br />0.050 cfs, is 32R of the historic (1980-2002) average flow value, 0.162 <br />cfs. However, the operation of the truck wash system, and the timing of <br />flow measurements, tends to greatly influence the flow values reported. <br />Review of the TDS plot indicates an increasing trend. <br />- Surface Water Site SW-S2-3 (SSG3). This site monitors discharges from <br />pre-SMCRA mining areas before they enter Grassy Creek at a point just <br />below Site SW-S2-2. This site was re-established in June 1997. Not <br />enough data has been collected yet to detect any trends. It was dry in <br />. June through September the past two years. <br />17 <br />