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required for AVF-5 under TC. <br />Historically, groundwater levels in the alluvium have remained fairly regular, with normal seasonal <br />fluctuations, apparently related to changes in river levels. POR groundwater levels in AVF-5 are plotted in <br />Figure 5. The data indicates no impact on alluvial water levels related to mining. <br />Field parameter data for AVF-5 for 2015 is presented in Table 10. POR water quality data is provided in <br />Table 11. A plot of field electric conductivity versus time is presented in Figure 6. There has been no <br />conclusive evidence of seasonal variation of water quality in the alluvium. AVF-5 was within historic levels <br />in 2015. <br />Water Sediments in the Williams Fork River Alluvium were historically monitored via three alluvial wells in <br />the general area of the loadout facilities and underground discharge sediment ponds. These include wells <br />AVF-3, AVF-5, and AVF-6. Historically, groundwater levels in the alluvium had remained fairly regular, <br />with normal seasonal fluctuations, apparently related to changes in river levels. Ground water levels for these <br />wells are also plotted in Figure 5. The data indicates no impact on alluvial water levels related to mining. <br />3.2 Surface Water Monitoring <br />3.2.1 Rivers <br />There are two rivers in the vicinity of the mine site. The Yampa River, flows in a southeasterly direction <br />across the mine site. The Yampa River drains most of the northeast corner of Colorado and part of south- <br />central Wyoming. The second river is the Williams Fork, which is a major tributary of the Yampa River. The <br />Williams Fork River joins the Yampa River on the mine property. Monitoring data is collected for the <br />Williams Fork River. <br />The United States Geologic Survey (USGS) had one gaging station and one staff gage for collection of <br />Williams Fork River flow data (former site 09249750). The Williams Fork River gaging station (WF -2) is <br />near the confluence with the Yampa River, downstream of the Eagle No. 5 Mine discharge. The staff gage <br />(WF -1) is located upstream of the mine discharge points. WF -2 is also monitored concurrent with WF -1. <br />The flow data for WF -2 was historically provided by the USGS, however, their monitoring of the Williams <br />Fork stations was discontinued in 2001. Historically, comparisons between up gradient site WF -1, and down <br />gradient site WF -2, have not show any stream depletion impacts from mine dewatering. In 2010 the State <br />Division of Water Resources (Office of State Engineer) reactivated the site. Data for the former USGS site <br />C-81-044 2015 AHR <br />