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<br />- r'- <br />C. V I <br /> <br />. <br /> <br />. <br /> <br />ranging from 10 to 150 feet lower; a third, westward to the evaporite <br /> <br />outcrops two miles below Basalt, a distance of l2~ miles and to an ele- <br /> <br />vation approximately l160 feet lower. <br /> <br />The downward gradients for these suggested paths of leakage could <br /> <br />range from less than 1% to l.4%. In each case geologic evidence indicate <br /> <br />a path through the evaporite would have to pass below a synclinal structure <br /> <br />which would force the water to pass through an inverted syphon effect and <br /> <br />a lengthened path of percolation. In each case the path would also pass <br /> <br />beneath a topographic ridge whereby the thickness of rock above the eva- <br /> <br />porite would be several thousand feet. The presence of known major faults <br /> <br />crossing the paths of possible water movement to the south and west poses <br /> <br />additional barriers to the escape of water. To the north the log of the <br /> <br />Pan American Oil Company "Tully" well shows no evaporite being present <br /> <br />at that location, which suggests that at least in some areas to the north <br /> <br />the evaporite is discontinuous. <br /> <br />To further evaluate the seepage possibilities of the evaporite <br /> <br />the writer made a field examination of the evaporite exposures along <br /> <br />Brush Creek, Gypsum Creek and a 20-mile stretch of the Eagle River, near <br /> <br />Eagle, Colorado, which is directly underlain by the evaporite. Although <br /> <br />the outcrops are similar to those at Ruedi, no evidence of water losses <br /> <br />from these streams into the evaporite was observed. <br /> <br />The preponderance of evidence from the above investigations is, <br /> <br />in the writer's opinion, heavily in favor of no significant leakage <br /> <br />through the evaporite. <br /> <br />- 13 - <br />