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are provided on Table 17. Water quality values were within the typical historical range of other wells in this <br />aquifer. <br />3.2 Alluvial Groundwater Monitoring <br />Table 18 presents a summary of alluvial well monitoring frequencies, which was last updated for Permit Revision <br />6 (PR 03-06) in March of 2004. <br />Alluvial ground water in the Twentymile Park Basin exists under unconfined conditions within the alluvial <br />materials underlying the major surface drainages of the area and backfilled areas of adjacent surface mined areas. <br />Stream flows are the primary source of recharge to the alluvial aquifers. Alluvial deposition is limited in areas <br />where stream gradients are relatively steep and in areas where the stream channel has eroded to or intersects <br />resistant bedrock. Consequently, the alluvial deposits do not tend to be continuous. Shallow wells completed in <br />these deposits indicate that they are usually less than 20 feet thick and the depth to ground water is typically less <br />than 10 feet. The limited extent of the Foidel Creek alluvial deposits, and the lack of base flow in the creek <br />indicates that these deposits are relatively insignificant to the area ground water hydrologic system. <br />Alluvial deposits containing groundwater are monitored in the Foidel Creek, Fish Creek, Trout Creek and Middle <br />Creek drainages. In the Foidel Creek drainage, sites both upstream and downstream of the TC portals and <br />support facilities are monitored. In the Fish Creek Drainage, sites upstream and downstream of the Mine 2 area <br />and the Fish Creek Borehole mine dewatering facilities are monitored. <br />Foidel Creek Alluvial Groundwater: There are four Foidel Creek alluvial wells, 009-S-10, 001-S-5, 008 -AV - <br />1, and 008 -AV -2. Tables 19 through 22 provide summaries of 2015 data collected at each site. Tables 19a <br />through 22a provide historical statistical summaries of collected data at each site. Figures 29 through 33 provide <br />graphical representations of water levels and selected water quality parameters recorded at these sites. <br />Water levels during 2015 remained generally consistent with established ranges and patterns and showed the <br />typical seasonal variability of elevated water levels in the spring. Note that the winters of 2007 and 2011 saw <br />some record snow falls, which is exhibited in the higher water level elevations detected. 2012 was a significant <br />drought year. 2015 was a good snow year. Well 009-S-10 provides data for the alluvial aquifer upgradient from <br />the mine portals. Water levels in 009-S-10 for 2006 (Figure 29) are consistent with observed historical seasonal <br />fluctuations. Conductivity values at well 009-S-10 (Figure 30) remain consistent with historical values. <br />Well 001-S-5 is located just downgradient from the mine portals and surface facilities location, and is monitored <br />in conjunction with surface water monitoring site 8. Water levels saw a rise due to record snow melt (Figure 33). <br />Conductivity values in 001-S-5 for 2015 (Figure 31 and 32) are consistent with observed historical seasonal <br />fluctuations. <br />Data for wells 008 -AV -1 and 008 -AV -2 are provided in Tables 21 and 22, respectively. 2015 data was consistent <br />with historical values. Water levels in these wells and the stream show the typical seasonal interrelationship of <br />8 <br />