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Mayo and /Issoeloles, LC <br />• Mantle cover springs also respond to climatic cycles. Climatic effects are especially evident <br />when the hydrographs are compared with the PHDI (Figure Z). For example, springs G-22 <br />and CR-12 (Figures 1 lb and 1 lc, respectively) both show the influence of climate variability. <br />The near drying up of the spring G-22 in 1981-82, 1988-92, and 1994-95 reflects dry periods <br />(Figure l lb). The effects of [he 1994-95 dry period are also evident in Figure l lc. <br />5.3 Landslide Deposits <br />The combined total volume of water discharged from the landslide springs is nearly twice <br />that of any other rock unit in the mine area (Figure 9). The discharge characteristics of <br />springs discharging from quaternary landslide deposits are, in most respects, similar to those <br />discharging from mantle cover groundwater systems. Landslide deposit springs are highly <br />• influenced by seasonal variations in precipitation. Thus, the travel times from the recharge <br />area [o spring discharge locations are less than one year. Groundwater systems that sustain <br />these springs have small storage volumes relative to the recharge and discharge rates. <br />All but three of the landslide spring hydrographs (G-26, G-49, and J-1) have periods of no <br />discharge almost every year (Appendix C). These three springs show tremendous seasonal <br />variation and decrease in flow to only one or two gallons per minute during the low flow <br />season. <br />The discharge of many of the landslide springs also responds to climatic cycles. For <br />example, springs G-l4 and G-24 (Figures 1 ld and 1 le, respectively) show both the influence <br />of season and climate. In Figure l ]d, the drought periods of 1981-82 and 1988-92 are <br /> <br />Characterization of Groundwater Systems in [he V icini[y of the Wes[ Elk Mine, Somerset, Colorado <br />29 January 1999 <br />Page 64 <br />