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A steeper gradient should be expected in the outcrop area of the Third White <br />Sandstone than in the outcrop area of the Second White Sandstone because of <br />the steeper land surfaces in the area of the Third While Sandstone. The <br />same hydraulic gradient in both sandstones would result in a lower piezo- <br />metric elevation in the Third Sdhite Sandstone at the same point. A large <br />amount of head difference would be needed to move a significant amount of <br />water through the Second Shale. The Second Shale is continuous in this area. <br />Movement in the Third White Sandstone is mainly down-dip in this area of <br />the aquifer. Ptovement of water in the Second White Sandstone is mainly <br />down-dip with a significant discharge in this area to the Pyeatt aquifer <br />system and thin sandstones in the Lewis Shale. Map M35A presents the <br />piezome[ric surface for the Third White Sandstone in the area of Pyeatt <br />Gulch. These contours form a similar shape as the structure contours on <br />• the base of the I coal (see Pfap M34). The gradient between wells P-1, <br />P-2 and P-3 is small and shows Chat the driving force perpendicular to the <br />drainage is not large. Very little water is being transferred between <br />the aquifer in the fill and the Lewis Shale, presently. A much larger <br />gradient has been observed in the Flume Gulch wells which shows that a sig- <br />nificant gradient exists perpendicular to the Flume aquifer system. <br />An estimate of the quantity of water flowing in Flume and Pyeatt Gulch caa <br />be obtained From the transmissivities, width of saturated fill material <br />and hydraulic gradient. A flow rate of 200 gpm is estimated fox the <br />Flume system near well F-1 from values of 25000 gpd /f t, 0.02 ft/ft aad <br />600 feet for [ransmissivity, gradient and width, respectively. Values for <br />transmissivity, hydraulic gradient and fill width of 6300 gpd/ft, 0.015 ft/ft <br />2-575 <br />