REP07588 - Laserfiche WebLink

Home Browse Search

Monitoring was initiated at Trout Creek alluvial well 008-AT-1 (Figure 66) during 1994. During 2000, no unusual observations are noted with respect to the Trout Creek alluvium groundwater levels. No unusual observations are noted with water quality remaining comparable to alluvial wells upstream of the site. Monitoring was initiated at Middle Creek alluvial well AVM-1 during 1996. During 2000, no unusual observations are noted with respect to the Middle Creek alluvium groundwater levels. No unusual observations are noted with water quality characteristics comparable to other alluvial wells in the area. Recorded surface water flows for Foidel Creek, Fish Creek, and Trout Creek (Table 56) were comparable [o TCC's period of record data. TDS concentrations a[ site 1005 (Table 53) on Trout Creek, downstream of all mining operations, peaked at 530 mg/I in July. TDS concentrations at site 800 on Foidel Creek, upstream of the mine facilities, peaked at 3430 mg/I in July. TDS concentrations at site 8 on Foidel Creek, downstream of the mine facilities, peaked at 3360 mg/I in July. No other notable water quality impacts are evident at any surface water sites monitored during 2000. Recorded 2000 spoil spring discharges remain negligible and, therefore, did not constitute a significant portion of discharge from [he TCC mine area with the potential to impact off-site areas. Discharges from sedimentation ponds predominately occurred in conformance with applicable NPDES permit limitations and therefore did no[ constitute significant impacts to receiving waters. Mine water discharge sites 109 (Table 64) and 1 IS (Table 65) produced little water during the 2000 Water Year. No unusual occurrences of inflow were noted as a result of the Annual Mine Inflow study. When pumping mine water from the Fish Creek Borehole (mine discharge site I15) the flow becomes a contributor to sulfate levels in Fish Creek. When pumping mine water from the EMD Dewatering Well (mine discharge site 109) the Flow becomes a contributor [o sulfate levels in Foidel Creek. Fish Creek and Foidel Creek, in tum, contribute to the sulfate levels in Trout Creek. Trout Creek has a secondary drinking water standard limiting sulfate to 250 mg/I. Historic sampling at site 1005 has shown that a sulfate level of 250 mg/I correlates to a conductivity of 750 umhos/cm. In order to quantify the predicted efTect of sulfate contributions from sites 115 and 109, TCC in association with a consultant, has developed a computer program -the "FCBH Calculator". In the winter, when stream gauging is difficult, the FCBH Calculator uses the flow of the Yampa River below Steamboat Springs (USGS 09239500), to predict the flow in Fish Creek (site 1005) and Trout Creek (site 69) above their confluence, and in Trout Creek (site 1005) below the confluence. In the summer, the FCBH Calculator uses measured Flows at these sites. Then, using measured flow and conductivity at sites 1 I S and 109, along with measured conductivity at sites 69 and 1005, the program calculates how much additional mine water, if any, may be discharged from sites I ] 5 and 109. TCC uses this method to ensure [hat the controllable discharge from site 1 I S does not create a sulfate exceedence in Trout Creek. 15