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February 2000 Chapter 3 Page 3-57 Saturated alluvium along the North Fork of the Gunnison River and primary tributary drainages (Terror and Hubbard creeks) has been developed for industrial, domestic, and livestock use. Area well yields range from 5 to 120 gpm and average 17 gpm (Bowie, 1998 and Oxbow, 1999). Several domestic wells are located at the mouths of Terror and Hubbard creeks. Oxbow utilizes an infiltration gallery for its main fresh water source. I he gallery is esiabiisiied in the alluvium of the North Fork of the Gunnison River south of Sanborn Creek. The reported maximum withdrawal rate is about 50 gpm (Oxbow, 1999). The alluvial groundwater resources in the North Fork of the Gunnison River, as well as in Terror and Hubbard creeks, are elevationally lower than the proposed mined coal seams and are outside the predicted zone of potential mine-induced impacts. Saturated alluvium is unconfined and is recharged primarily by seepage from rivers and streams and, to a minor extent, by discharge from water-bearing bedrock and direct precipitation. Groundwater flow gradient in the alluvium follows the local drainage topography. Water-bearing coAuvial deposits are found abng the slopes of area drainages and on.the gentle terrain of the ridge tops, as noted by the occurrence of numerous seasonal springs and seeps. These saturated deposits are perched, limited in lateral extent, and are not considered significant water resources. However, several local stockponds are constructed to collect the seasonal spring flow. Local springs and seeps issue from these zones during periods of high precipitation and snowmelt. Seasonal spring and seep flows range from less than 1 gpm to about 5 gpm and are reported to be dry from summer to spring except after major precipitation events. Direct precipitation and snowmelt recharge these deposits. Groundwater is unconfined, and the flow direction follows the local topography. The Wasatch Formation is cemposed of interbedded sandstone, siltstone, shale, and claystone. Sandstone beds are generally thin and limited in lateral extent. The Wasatch Formation outcrops on the gentle ridge tops of the Elk Creek Coal Lease Tract and Iron Point.Exploration License area. Groundwater occurrence has been identified from numerous seeps and springs. These springs are generally perennial and are associated with thih sandstone outcrops overlying shale or claystone beds. Flow rates typicaNy decrease during the summer and fail seasons (personal communication with Dan Hudson of Hotchkiss Ranches). Springs and seeps also issue from landslide deposits in the Wasatch Formation where slumping has juxtaposed permeable strata with low permeable material. Slumping features also form catchments that hold snowmelt runoff enhancing recharge potential. Springs that issue from landslide deposits are ephemeral, flowing only during the wet season and during periods of high precipitation (personal communication with Dan Hudson of Hotchkiss Ranches). The saturated zones in the Wasatch Formation are considered perched and with limited storage potential. Due to the outcrop logtion and gentle terrain of Wasatch Formation, recharge is primarily from snowmelt and direct precpitation infiltration. Numerous (about 40) local stockponds are fed from springs issuing from the Wasatch Formation. See Figure 19, Groundwater Hydrology. Based on mining and drilling data and spring and seep surveys, groundwater in the Mesa Verde Formation is limited to isolated sandstone beds in the barren and coal bearing members, the Rollins Sandstone member, various coal beds, and along fault and fracture zones. Low primary permeability and limited storage gpacity of the Mesa Verde Formation hydrogeologic units limit potential groundwater resource development (Brooks, 1983). However, significant quantities of groundwater are reported where the Mesa Verde Formation is fractured (Brooks, 1983).