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- 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 />nearly level 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 2370 mg/1 was observed. A value of 2341 mg/1 was predicted in <br />September, while a value of 3600 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 nearly <br />level. <br />Springs. <br />Spoil spring data may be found after the surface water data presented in <br />Appendix D. Spoil spring data provided are water quality data for the <br />year, historic flow measurements, and a LOWESS plot of EC (electrical <br />conductivity, corrected to 25° C, since 10/1/89) values, and finally a <br />listing of historic percent milliequivalent values for major ions and <br />TDS values. In addition, a flow hydrograph is provided for Spoil Spring <br />1. <br />- Spoil Springs 1 and 2. Both these spoil springs are located above the <br />NPDES D04 pond. Spoil Spring 1 is a large spring that was further <br />developed and fitted with a V-notch weir by the USGS on September 8, <br />1987. Its EC plot indicates a decreasing trend. Spoil Spring 2 is a <br />small spring creek on reclaimed land that flows adjacent to Spoil Spring <br />1. Spoil Spring 2 has recently exhibited a decreasing EC trend. <br /> <br /> <br /> <br />IS <br />