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The hydrologic description of the mine area is provided in Tab 7 of the permit, and <br />the hydrologic monitoring plan is addressed in Tab 15. Hydrologic protection, <br />probable hydrologic consequences, and the hydrologic reclamation plan are <br />presented in Tabs 16, 17, and 18, respectively. <br />Surface water at the Seneca II -W Mine lies within two watersheds. The primary <br />affected area lies within the Dry Creek Drainage and is drained by Hubberson Gulch <br />and an unnamed tributary to Dry Creek (the Pond 005 Gulch). A small portion of <br />the eastern part of the permit area drains to Sage Creek. Both creeks empty into the <br />Yampa River near Hayden. Both Dry Creek and Sage Creek exhibit intermittent to <br />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 <br />addition to NPDES monitoring sites located at Pond 017 outfall on upper Hubberson <br />Gulch, 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 <br />the 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 <br />the parameters listed in Appendix 15-1. The TDS plot in the 2009 AHR indicates <br />an increasing trend. The PHC predicts an irrigation season average TDS value of <br />2193 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 <br />and SG17 were the baseline sites for Ponds 016 and 017, respectively. These sites <br />have been replaced by Colorado Discharge Permit System (NPDES) monitoring sites 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 <br />2451 mg/1 at this site, while a value of 1860 mg/l was observed in 2009. The <br />ephemeral drainage tributary to Dry Creek, which drains the "D" Pit reclamation <br />area in the northern portion of the original permit area, is monitored at the Pond 005 <br />outfall NPDES site. <br />