2008-01-14_HYDROLOGY - M1977215 - Laserfiche WebLink

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~ ~~°~ed JAN 14 20a8 DUra~~o ~.a ~yp~ ~Pi!($l~ r ~`"7~ ,""'cam' no,~~ ~~"~'~9 app Mr. Alan Cox Homestake Mining Co. of California ~P.O. Box 98 Grants, NM -87020 ~, ~ L.l.~~ ~- ill ~ N~ /rl;~4vtl~ ~' ~~ ~'~ "21ri Dear Mr. Cox tGC.t~ ~~~ ~~~ ~~ W1'~TER ,MANAGEMENT CONSULTANTS `A Schlumberger Company 1875 LAWRENCE STREET, SUITE 500 DENVER, COLORADO 80202, USA TELEPHONE: (303) 297 9005 TELEFAX: (303) 297 9007 Bulldog Mine Reclamation Project, Mineral County, CO Water Quality Monitoring in Windy Gulch November 30, 2007 RECEIVE® ,IAN 18 2008 Division of Reclamation, Mining and Safety This letter provides a summary of the water quality monitoring activities that have been conducted by Homestake in Windy Gulch in 2007, which is the fourth year that water quality samples have been taken in Windy Gulch since completion of reclamation activities in late 2002. Windy Gulch did not flow below Bachelor Road during 2003 due to the regionally dry conditions so no water samples could be obtained in 2003. The first three years of sampling were conducted in 2004, 2005, and 2006 and the results were provided in our previous summaries dated August 9, 2004, September 6, 2005, and September 16, 2006 respectively. The monitoring in Windy Gulch follows the plan described in our August 23, 2002, letter to the Forest Service. As per this monitoring plan, the goal for reclamation efforts is to meet agricultural standards in Windy Gulch at the lower weir, which is near the confluence of Windy Gulch and Willow .Creek. Monitoring activities have included the measurement of flow at the upper weir (at Bachelor Road) and the lower weir (at the mouth of Windy Gulch) located as shown in Figure 1. Water quality samples were also collected at each location for laboratory analysis. Flows measured during 2007 at the upper and lower weirs in Windy Gulch are shown on Figure 2. The 2004, 2005, and 2006 measured flows are also shown for comparison. In 2007 flow in Windy Gulch was similar to the flow levels observed in 2004 and 2005. Flow in Windy Gulch in 2006 was minimal as seen in Figure 2. Flow during 2007 at the upper weir ranged from zero to a high of about 3.7 cfs (1660 gpm) on April 25 and then decreased to 0.07 cfs (32 gpm) by July 6. Flow in 2007 at the lower weir ranged from zero to a high of about 2.7 cfs (1120 gpm) on May 2 and decreased to minimal flows (below 0.01 cfs) by mid June. Water quality samples were taken at the upper and lower weir locations six times in 2007. The results of the chemical analyses for the 2007 samples are shown in Table la and lb. Results from the 2006, 2005 and 2004 sampling rounds are included in Tables 2, 3 and 4 respectively, for comparison. For some constituents, both total and dissolved analyses are shown. The total analyses often show higher constituent levels since they include any sediment contained in the water as well as the dissolved constituents. A comparison of the results to the agricultural standards set as water quality goals in the August 23, 2002, plan is included. Average concentrations from 16 samples taken during the 1998 to 2001 period (i.e., prior to the fmal reclamation activities in Windy Gulch) are also shown for comparison.