2019-03-11_REPORT - C2009087 (2)

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Surface Water Site YSG5. This site is the furthest downstream surface water site in the Little Grassy, Scotchmans Gulch and Grassy Creek drainages after exiting the PSCM permit area. It displays an increasing TDS trend, with the peak value occurring in August 2013. The PSCM PAP addresses potential impacts to surface water quality on pages 2.05-84 to 91 (Vol. 1A). A summary of those impacts is presented on Table 2.05.6(3), page 2.05.89. The Probable Hydrological Consequences (PHC) focus on impacts caused by underground mine dewatering. As that scenario has not occurred yet, the PHC predictions are not yet relevant. However, on page 2.05.88, it is stated "...Pond 002 is heavily affected by high-TDS water from the Seneca II spoils aquifer, and averages nearly 4000 mg/1". This year, the average TDS at Pond 002 (NPDES2) was 3678 mg/l, and its TDS trend is increasing (see above). At Site YSG5 this year, the average TDS was 1097 mg/l. Springs. Spoil spring data may be found after the surface water data presented in Appendix D. Spoil spring data provided are water quality data for the past year, a hydrograph of historic flow measurements and a LOWESS plot of TDS values. Spoil Springs 1 (NPDES 006) and Spoil Springs 2 (NPDES 005). Both these spoil springs are located above the NPDES 004 Pond. Spoil Spring 1 is a large spring that was further developed and fitted with a V -notch weir by the USGS on September 8, 1987. Its TDS plot indicates an increasing trend, with the peak TDS value occurring in 2015. Spoil Spring 2 is a small spring creek on reclaimed land that flows adjacent to Spoil Spring 1. Spoil Spring 2 exhibits a slightly decreasing TDS trend. Monthly sampling began in April 2015 to gather information for bond release. Spoil Springs 3, 4, and 5. These springs all exist in the Wadge coal seam mining area in the Little Grassy Creek basin. Spoil Spring 3 drains out of an old backfilled mine 15