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perennial flows, depending on location along the streams, and precipitation trends. <br />Hubberson Gulch is intermittent. <br />Hubberson Gulch Watershed <br />Seneca Coal Company currently monitors one upstream site (SG9) and one site <br />downstream of mining disturbance on Hubberson Gulch (FG1). These are in addition <br />to NPDES monitoring sites located at Pond 017 outfall on upper Hubberson Gulch, <br />and Pond 016 and 006 outfalls on Hubberson Gulch tributaries. <br />SG9 is located upstream from Pond 017, and above any mine related discharges in the <br />south extension area. Monitoring was conducted from 1997 through 1998, and <br />reinitiated in 2000, with monitoring conducted June and September. <br />FG1 (Hubberson Gulch downstream of 006 Gulch confluence) is equipped with a <br />continuous flow recorder and water quality samples are obtained semiannually for the <br />parameters listed in Appendix 15-1. The TDS plot in the 2009 AHR indicates an <br />increasing trend. The PHC predicts an irrigation season average TDS value of 2193 <br />mg/l for this site, while a value of 2,410 mg/l was reported in the 2003 AHR. <br />SG9, SG16 and SG17 were added to the monitoring program within PR-02. SG16 and <br />SG17 were the baseline sites for Ponds 016 and 017, respectively. These sites have <br />been replaced by Colorado Discharge Permit System (NPDES) monitoring sites <br />located at the Pond 016 and 017 outfalls. <br />Dry Creek <br />One site is monitored on Dry Creek, downstream of mining (SG5). Flow, field <br />parameters, and water quality samples for the parameters listed in Appendix 15-1 are <br />taken semiannually. The TDS plot included in the 2009 AHR indicates an increasing <br />trend. The Seneca II-W PHC predicts an average irrigation season TDS value of 2451 <br />mg/l at this site, while a value of 1860 mg/l was observed in 2009. The ephemeral <br />drainage tributary to Dry Creek, which drains the "D" Pit reclamation area in the <br />northern portion of the original permit area, is monitored at the Pond 005 outfall <br />NPDES site. <br />Sage Creek <br />SCC monitors one NPDES site on Sage Creek, at the Pond 009 outfall. Flow and field <br />parameters are recorded monthly upstream, and monthly samples are taken for the <br />parameters listed in Appendix 15-1. In addition, SCC monitors an NPDES site at the <br />Pond 015 outfall, located on a south tributary of Sage Creek. <br />Seneca Coal Company has installed a sediment control system to divert, convey and/or <br />treat surface water runoff in and around the mine site. The sediment control system <br />includes seven sedimentation ponds (Ponds 005, 006, 009, 0 t 5, 016, 016A and 017). <br />Seneca II-W Findings Document 35 C1982057 <br />Permit Renewal No. 5 December 9, 2010