1986-06-13_GENERAL DOCUMENTS - C1981018

Home Browse Search

Ground Water Movement Ground water movement in the Deserado Mine area was determined through the construction of potentiometric surface maps of the three bedrock zones. Data from 30 holes was used to construct the potentiometric surface map for the Upper Sandstone Facies. Data from eight holes was used to construct the map for the Coal and Siltstone Facies, while data from 6 holes was used to construct the potentiometric surface map for the Lower Sandstone Facies. Ground water movement in the Upper Sandstone Facies above the.coal follows the strike and dip of the gentle limb of the Red Wash syncline until topographic control takes over near the White River. As a result, a ground water divide exists and generally follows the northern boundary of the coal lease area. Ground water south of this divide flows toward the southeast. The recharge to the upper sandstone facies occurs in the topographically higher hills to the west of the Deserado Mine area and flows toward the alluvium of Scullion Gulch, Red Wash and the White River. The influence of Scullion Gulch on the movement of ground water in the area probably results from the channel cutting through the Siltstone and Coal Facies, which underlies the Upper Sandstone Facies. The potentiometric surface map for the Siltstone and Coal Facies show the same trends as the map for the Upper Sandstone Facies. In the higher areas to the north, ground water tends to follow the general geologic structure. To the south, the influence of topography and Scullion Gulch redirect the flow of ground water toward the White River. The potentiometric map of the Lower Sandstone Facies also shows a similar trend of ground water movement. However, movement appears to be more parallel to the axis of the Red Wash Syncline than that observed in the other zones. South of the divide, ground water still flows from the high topographic area toward the White River. Recharge of the Lower Sandstone Facies, is primarily from the north where these strata outcrop near Highway 40. The tendency for the ground water in all three facies to flow south easterly one-or-two one-otwo miles of', the White River rather than continuing toward the axis of the syncline implies that the flow is likely discharging into the White River alluvium. Stereoscopic and aerial observations give some evidence that the White River is following a fracture or fault in the area adjacent to the Deserado Mine area which may be conveying the deeper ground water up into the alluvium. Red Wash also may be flooding a fracture zone extending down Red Wash and Spring Creek, ;which permits water to move more readily to the south once the fractured sandstone is reached. Depth to water varies from 50 to 200 feet under the surface in most of the area, and hence, the only evidence of seeps is where shallow, silty layers impede downward flow from an adjacent drainage. Vegetation along the White River does not show evidence of near-surface, long-lasting seepage. It is expected that ground flows primarily from the middle and u er P 9 P Y P� sandstone facies into the White River alluvium, . However, because of t e low permeability of this formation, this flow is expected to be very limited. A rough estimate of the ground water flow within the mine boundary as it flows towards the river was madejby utilization of the hydraulic equation Q =