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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, 1968. This year's average flow value, <br />0.063 cfs, is 40~ of the historic (1980-2003) average flow value, 0.159 <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 three years. <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 />effects of mining in this area. Review of the TDS plot indicates a <br />slightly increasing trend. <br />On page 7-242 of the Seneca II PHC, predictions of TDS values at this <br />site were made. A value of 1233 mg/1 was predicted in June, while a <br />value of 2200 mg/1 was observed. A value of 2341 mg/1 was predicted in <br />September, while a value of 3370 mg/1 was observed. It should be noted <br />that the PHC predictions were based on long-term average values. <br />Individual monthly TDS measurements may be affected by annual changes in <br />climate (such as the lower than average precipitation noted the past <br />several years), and_by the relative contribution of flow values from <br />Ponds 002 and 003 (as affected by the truck wash system). The long term <br />TDS trend for this site, as stated in the previous paragraph, is <br />increasing only slightly. <br /> <br /> <br />18 <br />