2010-03-22_REPORT - C1980005 (2)

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1984CY = 1.439 cfs If 1983CY = 0.531 cfs it 1982CY = 0.547 cfs IF 1981CY = 0.098 cfs if 1980CY = 0.990 cfs If This year's average flow value, 0.630 cfs, is 12% above the historic (1980-2009) average flow value, 0.563 cfs. The timing of when flow values are collected affects these averages. Flow values at this site were affected by the pumping of water from this pond for the truck wash system and for water trucks (dust control). Pumping for the truck wash system began on September 18, 1984. Also, the upper end of this pond was regraded in 2002. Review of the TDS plot indicates a recently stable trend (SF 0.2), with the peak value occurring in August 2006. Grassy Creek Drainage. Four monitoring sites lie within the Grassy Creek drainage: Site 1, located upstream on Grassy Creek; NPDES Discharge Point 003, also known as the Shop Reservoir or the Northwest Impoundment, located just north of the mine shop area; Site 2, located approximately 0.1 mile downstream of where NPDES3 discharges into Grassy Creek; and Site 3, which monitors discharges from pre-SMCRA mining areas and is located adjacent to Site 2. - Surface Water Site SW-S2-1 (SSG1). This site monitors Grassy Creek upstream of mining at the Seneca II Mine. Review of the TDS plot indicates a slightly increasing trend. - NPDES Discharge Point 003 (NPDES3). Hydrographs presented in Appendix D show that flow has increased at this site since September 18, 1984, when operation of the truck wash system began. Water is siphoned from the Wadge Impoundment (NPDES2) into a holding pond. Overflow from the holding pond is diverted into the shop ditch, which flows into NPDES3. Water is pumped from the holding pond to the wash rack, drains into a settling pond, and then into the same shop ditch. This operation has 0 increased the flow at NPDES3 while decreasing the flow at NPDES2. 15