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Mayo and Astoelaiet, LC <br />• reflected by [he diminished spring-time peak discharge rates. Similar responses are seen in <br />Figure lle. <br />Samples from nine landslide springs were collected during the low flow season of 1998 for <br />'H and "C analyses (Table 5). Groundwaters from all of the springs contain anthropogenic <br />"C and elevated'H contents. The unstable isotopic compositions of these springs indicate <br />that [hey contain modem recharge water, which is consistent with the spring hydrographs. <br />Springs sampled for unstable isotopic compositions include the three springs (G-26, G-49 <br />and J-1) that have not been observed to go completely dry implying that these springs are not <br />supported by deep groundwater systems. <br />• 5.4 Barren Member Springs <br />Almost all bedrock springs issue from the Barren Member and all exhibit seasonal <br />fluctuations as exemplified in Spring G-8a (Figure 11 f). Most Barren Member springs either <br />dry up or nearly dry up during the fall and winter months. The effect of wet and dry climatic <br />cycles also affects the discharge rates of Barren Member springs as exemplified in the <br />hydrograph of spring G-1 a (Figure l lg). In Figure 11 g, [he drought period of 1988-92 is <br />clearly evident. <br />Spring discharge rates from most Barren Member springs are less than 10 gpm during the <br />high-flow season, suggesting that these springs do not have the same high level of hydraulic <br />communication with snowmelt and surface water as do many springs issuing from <br />. unconsolidated deposits. The general shape and the seasonal and climatic responses of <br />Characterization of Growidwater Systems in the Vicinity of the West Elk Mine, Somerset, Colorado <br />291anuary 1999 <br />Page GS <br />