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$2,04 APPLICATION FOR PERMIT FOR SURFACE OR UNDERGROUND MINING ACTIVITIES -- <br />MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES. <br />2,04,7 Hydrology Description. <br />(1) (b) (Cont'd.) <br />Potential recharge to the Mesaverde Formation occurs <br />within the major stream drainages, while flowing, <br />(Brooks, 1983). Additional recharge of much smaller <br />magnitude could occur at the outcrop, yet the near ver- <br />tical exposures and sporadic precipitation preclude any <br />large scale infiltration. <br />Upper Mesaverde Formation - Perched Groundwater Above <br />the "D" Seam <br />There are several saturated sandstone strata above the <br />"D" coal seam. These strata are not continuous and are <br />present only in several wells drilled within the permit <br />area. Hydrologic characteristics of these sandstone <br />lenses were obtained from monitoring wells DH-47 and GR <br />77-7. A pumping test performed in DH-47 indicated a <br />yield of 11 gpm and an average transmissivity of 433.3 <br />sq. ft, per day. Groundwater in this strata is of so- <br />dium sulfate type with total dissolved solids in a <br />. range of 300 to 750 mg/1. <br />The shallow depth of this interval (DH-47 test) and <br />casing density log interpretation indicate this horizon <br />is near the colluvium- bedrock interface, with the wa- <br />ter quality suggesting recharge or source of the water <br />to be near-surface colluvial in origin. Typically, <br />casing was set through the colluvial mantle and in the <br />case of DH-47, this depth was 228 ft. The occurrence <br />of saturated, weathered bedrock at the colluvium- bed- <br />rock contact presumably created a perched groundwater <br />occurrence, which is probably recharged by near surface <br />colluvial sources. <br />Exploration hole GR77-7 was drilled by the U. S. G. S. <br />Conservation District during August 1977, and cased as <br />a U.S.G.S. water Resources Division observation well on <br />August 13, 1977. Although hydrologic test data is un- <br />available for this hole, Brooks (1983) concluded, "The <br />water in well SCOI309214CB01 (GR77-7) probably is af- <br />fected by a ground-water and surface-water connection. <br />Depth to water in this well was less than would be ex- <br />pected in wells penetrating the Mesaverde Formation in <br />. Added 03/07/85 <br />Revised 10/01/87 <br />37 <br />