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permit database (CDM 2005), of which 1,247 have been retained for this analysis. The <br />specific capacity data were then converted to a transmissivity value using an equation <br />which incorporates standard assumptions. The entire process of data collection and <br />calculation results in a data point considered to be an acceptable approximation of the <br />aquifer's T but of a lower level of certainty than an aquifer pumping test. Specific <br />capacity test data were used to provide a broader distribution of data than aquifer test <br />results provide. Section 1.2 discusses the specific capacity data retained for use in <br />subsequent analyses. <br />A third category of aquifer property data are published contour data for which the <br />underlying point values are not available. During SPDSS Phase 1 the contoured <br />storativity data presented in this TM were obtained from Robson (1983) and were <br />digitized and incorporated into the SPDSS data sets used for analysis and mapping. The <br />source data and methods used to calculate the contours presented in Robson (1983) are <br />not available. It is assumed aquifer test data available in previous reports (Wilson 1965) <br />were used in preparation of the contours and other data were acquired from <br />unpublished sources which are not available to the SPDSS. Comparison of the Robson S <br />values to aquifer test-derived data points have been performed and the results <br />determined to be acceptable. It is believed the data contained in Robson (1983) are a <br />valid supplement to other data sources for development of a regional scale groundwater <br />model despite the uncertainties in how the data were developed. These data have been <br />provided to the State in the form of GIS shapefiles. <br />A final category of aquifer property data used in this report are from laboratory testing <br />of aquifer materials which directly examines the physical properties of a sample of the <br />aquifer material. Data of this type are often easier to collect than data from the previous <br />categories, but may be of more limited use due to either 1) the potential for degradation <br />of the sample due to inadequate methods of collection, preservation, and analysis or 2) <br />the fact core samples may represent a very small portion of a heterogeneous aquifer. In <br />a heterogeneous aquifer consisting of interbedded clay/shale, silt, sand, and gravel, a <br />core sample could represent the properties of any one of these materials rather than the <br />bulk aquifer property. Aquifer property values obtained from core samples have been <br />useful in developing a conceptual understanding of the Denver Basin bedrock aquifers' <br />interbedded nature and will assist in assigning an anisotropy value in a groundwater <br />model. No laboratory analyses were performed under Phase 2 of the SPDSS, but <br />laboratory data obtained during Phase 1 are presented herein. <br />Aquifer property values obtained from each of the different data types are indicated in <br />the database which will be incorporated into HydroBase. Aquifer pumping tests are <br />referred to as "constant discharge" tests, specific capacity and laboratory tests are <br />indicated as such. Data obtained from contoured data are not provided in the SPDSS <br />database but will instead be included as separate GIS shapefiles. <br />1.2 Data Analysis and Processing <br />Data collected during Phase 1 and Phase 2 have been used in the aquifer property <br />analysis and mapping presented in this TM. These data came from a variety of sources, <br />resulting in the aquifer T or K data being reported in several different types of units or <br />SPDSS Phase 2 Task 43.2 TM -Final 7 <br />2/ 13/ 2006 <br />