2013-04-10_PERMIT FILE - C2010089

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POTENTIAL IMPACTS TO SURFACE WATER RIGHTS FROM PUMPING FOR MINE DEWATERING The BBA Report describes in detail the analysis of pumping for mine dewatering as to the NH 2, NHN and Cyprus areas. Because the mined area is constantly in a state of movement, the BBA Report established an approximate centroid of pumping. Pumping for mine dewatering intercepts groundwater that would have eventually returned to the stream system and immediately returns it to the stream system. The BBA Report evaluated the impact to the stream, and found that more water would be delivered to the stream system in May through September than the amount that would occur absent pumping. This over - delivery actually benefits the surface water rights that are being used for irrigation. There is a credit to the stream from this mine dewatering, but it is not included in the accounting at this time. WFC reserves the right to claim such credit if necessary in the future. Mine dewatering at NH2 potentially impacts Tuttle Draw at a point below the Holder and Charlie Rice Ditches. In the NHN area, most of the mined area is in the Coal Canyon drainage. The report analysis determined that the impact of mine dewatering in NHN occurs west of the area in the Coal Canyon drainage. In the Cyprus area, the point of impact to Calamity Draw appears above the Richards Waste Ditch. In the month of April, lagged depletions from mine dewatering are slightly more than direct depletions from mine dewatering, and may have an impact on the stream system. While the CC Ditch usually starts in mid -April or early May, some irrigation ditches may start sometime in late April. The flow in Tuttle Draw is usually low in April until bolstered by irrigation return flows from the CC Ditch water returning to the system. In the unlikely event of a senior call, a storage release from a WFC pond would replace the mine depletions. AUGMENTATION OF DOWNSTREAM SURFACE WATER RIGHTS. An extensive search was conducted for the active water rights that could have a potential to place a river call in Calamity Draw, Tuttle Draw and Coal Canyon. That review involved a thorough review of the structures in the DWR database, as well as numerous discussions and a field inspection with the local DWR Water Commissioner. Most of the irrigation ditches on Calamity and Tuttle Draws are inactive, abandoned or non - existent. No ditch has placed a call on those tributaries in recent history. The only active structure identified in Calamity Draw below NHN Ponds 7 and 8 was the Richards Waste Ditch located at the bottom of the draw just above the confluence with the San Miguel River. If this ditch places a call, WFC will release CU credits from the CC Ditch to replace its diversions at the Elliot Lateral Headgate and run it down their ditch and into Calamity Draw. WFC can also release water from Pond 8 if necessary. On Tuttle Draw, there are two active ditches with water rights near the mining areas: the Charlie Rice Ditch and the Holder Ditch. The Charlie Rice Ditch is located on Enstrom (a/k/a Instrom) Draw, which is a small tributary of Tuttle Draw. Its headgate is located just west and downstream of the current NH2 mining area. According to the BBA Report, as shown in 11