2013-03-14_REPORT - C1982056 (3)

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impact flow calculations. In the summer of 2007, TC hired consultants (Rivers Unlimited, Inc. of Steamboat Springs, and Norwest Applied Hydrology of Denver) to assist with re- evaluating key stream bed locations, including rating curves for ongoing stream gauging. This on -going study continued into the spring, summer and fall of 2012. Gage calculations for 2012 have not yet been completed by the consultant, but will be submitted in 2013 as an addendum to this AHR. In 2008 and 2011 the consultants assisted with the temporary repair of some gage stations, however the accuracy of some of the gage readings are suspect. Gage calculations by Rivers Unlimited for 2012 should be viewed as being more accurate than field gage readings. In 2012, four protective enclosures were constructed by Rivers Unlimited at historic flow meter recorder locations. New recorders were installed and activated in May of 2012. Additional flow meters may also be added in 2013. The meter locations include sites 16A, downstream of 8, 1003, and site 69. Foidel Creek: 2011 was a significant drought year that saw Foidel Creek go dry in July through most of September. Four surface flow monitoring sites on Foidel Creek (in the vicinity of the TC mine portals and facilities areas) are utilized. Site 800 and site 14 are located upstream of the portal. Site 8 is located off the TC facility, downstream of Pond G. It is TC's intent to present a minor revision in 2012 to relocate site 8 further downstream to an area that is easier to access, and which would also be downstream of potential discharge from a future mine dewatering site. Site 900 is located further downstream on Foidel above the confluence with Middle Creek. Former site 304 was located further downstream of 900. Site 304 was eliminated in 2003 per TR03 -42. Tables 33 through 36 provide summaries of the 2012 Water Year data collected at each site. Tables 33a, 34a, and 35a provide POR statistical summaries of collected data at each site. Figures 52 to 59 and 102 to 105 provide graphical representations of water levels and selected water quality parameters recorded at each site. Typical flow patterns were exhibited at these sites with spring runoff periods accounting for the peak flows observed. At all of these sites, the inverse relationship between flow and field conductivity continues to be evident. Water quality parameters for these sites were within previously established ranges. An increase in conductivity at site 8 has been noted over the last two years. This is attributed to increased discharge from Pond D, resulting from overflows from the Area # 1 Pit (via DRMS site 7), which is partially fed by mine water as part of mine dewatering operations for the old WMD and EMD. TC has been considering alternate treatment options for 10 RT mine water. This may not occur until 2014 or later, depending on available funding. Fish Creek: 2011 was a significant drought year that saw Fish Creek go dry during most of August. Nine surface flow monitoring sites are utilized on Fish Creek. Site 16A replaced site 16 in 2000, and is located upstream of the Fish Creek Borehole discharge site 115. Historical data for site 16 may be found in previous AHRs. Site 307 is located approximately one mile downstream of the Fish Creek Borehole mine dewatering site and is monitored in conjunction with alluvial well 006 -AZ -3. Site 302 is located approximately two miles downstream of the Fish Creek Borehole mine dewatering site. Site 305 is located upstream of the Fish Creek Tipple and is monitored in conjunction with alluvial well 008 -AU -3. Site 27A is located immediately upstream of the Fish Creek Tipple discharge (a.k.a. CDPS discharge site 62). Site 1003 is located downstream of the Fish Creek Tipple site 62. 11