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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. <br />Other events have affected the long-term hydrograph at NPDES 003. They <br />include the diversion away from NPDES 003 of the runoff from an inactive <br />fly ash pit (operated by the Hayden Station power plant) in October 1980 <br />and the diversion away from NPDES 003 of runoff contained in the <br />Northwest Diversion Ditch (see the Seneca II Permit Application, Exhibit <br />7-7, Surface Water Hydrology map and also the 1982 Seneca II AHR) in <br />April 1982. Discharge volumes at the 003 site have also been affected by <br />the reduction in diameter of the discharge culvert (36 inches to 6 <br />inches) that occurred on July 19, 1988. Finally, a smaller volume pump <br />and line from 002 to the truck wash was installed in August 2001. <br />This year's average flow value, <br />(1980-2008) average flow value, <br />the truck wash system, and the <br />greatly influence the flow value; <br />at all this year. Review of <br />decreasing trend. <br />0.056 cfs, is 61% below the historic <br />0.146 cfs. However, the operation of <br />timing of flow measurements, tends to <br />reported. The truck wash was not used <br />the TDS plot (SF = 0.5) indicates a <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. TDS <br />values at this site exhibit a stable trend. This site was flow from <br />April through September this year. <br />- Surface Water Site SW-S2-2 (SSG2). This site is the furthest <br />downstream surface water site in the Little Grassy and Grassy Creek <br />drainages prior to exiting the permit area. Therefore, it is the most <br />significant monitoring site with respect to showing the cumulative <br />15