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Table 5: Summary of Laboratory Specific Yield (S~) Data (dimensionless) <br /> <br />Aquifer <br />Count <br />Minimum Lower <br />Quartile <br />Median Upper <br />Quartile <br />Maximum <br />Average <br />Upper Dawson1 10 0.036 0.094 0.17 0.26 0.34 0.18 <br />Lower Dawson1 14 0.036 0.094 0.15 0.21 0.27 0.15 <br />Denver 26 0.002 0.074 0.14 0.25 0.46 0.17 <br />Upper Arapahoe2 7 0.033 0.17 0.23 0.26 0.27 0.20 <br />Lower Arapahoe2 16 0.056 0.14 0.18 0.25 0.40 0.19 <br />Laramie-Fox Hills 30 0.048 0.13 0.21 0.23 0.38 0.20 <br />i Data include 9 values from undesignated Dawson Aquifer (Robson, 1983) <br />z Data include 7 values from undesignated Arapahoe Aquifer (Robson, 1983) <br />Table 6: Summary of Storage Coefficient (S) Data (dimensionless) <br /> <br />Aquifer <br />Count <br />Minimum Lower <br />Quartile <br />Median Upper <br />Quartile <br />Maximum <br />Average <br />Upper Dawson 0 N/A N/A N/A N/A N/A N/A <br />Lower Dawson 0 0.00 N/A N/A N/A N/A N/A <br />Denver 1 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 <br />Upper Arapahoe 0 N/A N/A N/A N/A N/A N/A <br />Lower Arapahoe 14 0.00002 0.00015 0.0003 0.00044 0.008 0.00089 <br />Laramie-Fox Hills 13 0.00002 0.0001 0.0003 0.00174 0.004 0.0011 <br />3.1 Hydraulic Conductivity (K) Data <br />The K values of each aquifer were compiled and analyzed for trends in geographic and <br />statistical distribution. The K values presented here represent the hydraulic <br />conductivities of the aquifer's water-yielding beds rather than the overall aquifer. This <br />is consistent with the methodology used by Robson (1983). It should be noted <br />additional processing will be required to determine K values for model input that will <br />include the non-water-yielding materials. Table 3 summarizes the number of data <br />points analyzed, statistical groupings, and the range of values observed by aquifer. In <br />many cases the geographic or spatial trends in K values can be related to the geologic <br />environment of deposition. A general concept for sedimentary rocks, such as those that <br />comprise the Denver Basin bedrock aquifers, is that K is generally proportional to grain <br />size. Grain size distribution of the sedimentary rocks is also generally related to how <br />close an area is to the original source of the sediment, so one can relate the spatial trends <br />in K to the original depositional environments. <br />The Dawson, Denver, and Arapahoe Aquifers are comprised of fluvial deposits, lain <br />down as sediments deposited by rivers flowing eastward out of mountains to the west <br />(Romero 1976). This type of deposit consists of gravels, sands, silts and clays, often with <br />low K silt or clay/shale deposits interbedded between higher permeability silt, sand and <br />gravel deposits. The layered nature of these deposits results in predominantly lateral <br />groundwater flow within the aquifer. In addition to this vertical heterogeneity within <br />the aquifers, beds within fluvial deposits can be laterally discontinuous; resulting is <br />SPDSS Phase 2 Task 43.2 TM -Final 18 <br />2/ 13/ 2006 <br />