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Appendix A: Instructions to Query Water Levels from HydroBase for Contouring the <br />Denver Basin Bedrock Aquifer Water Level Surfaces <br />1.0 Purpose/Objective <br />To document the procedure used to query the water level picks from HydroBase for contouring the Phase <br />3 Denver Basin Region water surfaces. <br />2.0 Procedure/Approach <br />The following procedure was used to query spring bedrock water level data from HydroBase: <br />1) In the SPDSS Phase 3 Groundwater Database, the table WELLS_DSS_AQUIFERS contains the aquifer <br />codes assigned to wells in the WELLS table during Phase 1 and 2. A select query was defined to create <br />two new fields DSSAquiferl and DSSAquifer2 by first using the values reported in aquiferl and aquifer2 <br />codes in WELLS_DSS_AQUIFERS and if those values are null, using the aquiferl and aquifer2 codes in the <br />WELLS table. <br />2) In ArcGIS a spatial query was performed to identify all wells located within the SPDSS Denver Basin <br />Region study area (the combined area of the Laramie-Fox Hills aquifer and the Complex Area) using a 2- <br />mile buffer. The results of this spatial query were used to populate a temporary lookup table, <br />SPDSS_REGION. This table contains the well_id and a new field, spdss_reg, indicating the well is located <br />in the SPDSS study area. The table is linked to the WELLS and WELL_MEAS table by the well_id field. <br />3) A query of the WELLS table was performed to identify any wells in the WELLS table with an <br />aquifer_commentnoting a USGS primary aquifer code that did not already have values for DSSAquiferl <br />and/or DSSAquifer2 fields and is located in the SPDSS study area. The USGS aquifer codes were <br />correlated to SEO aquifer codes and the appropriate SEO aquifer code was placed in the aquiferl and <br />aquifer2 fields of the WELLS_DSS_AQUIFERS table. <br />a. If a well was located in the Dawson or Arapahoe aquifers a second spatial query was <br />performed to determine if the well is located in the divided portion of the aquifer. It the well <br />was located in the divided portion of the aquifer the DSSAquiferl and DSSAquifer2 fields were <br />populated with UTDW (or UKA) and LTDW (or LKA) respectively. In cases were the well is <br />located in the undivided portion of the aquifer the DSSAquiferl field was populated with <br />TDW or KA as appropriate. <br />4) In Microsoft Access, the WELLS, WELL_MEAS and SPDSS_REGION tables were linked via well_id <br />field. Selected fields were chosen from the WELLS table (location and aquifer information) and all fields <br />were chosen from the WELL_MEAS table. A query using the DSSAquiferl and DSSAquifer2 and <br />meas_date fields was used to identify the spring water level measurements for a well in a given year. The <br />queries are depicted below. <br />Upper Dawson Aquifer <br />a. DSSAquiferl = "UTDW" AND DSSAquifer2 = Is Null AND SPDSS_REG = "SPDSS" AND <br />Year(meas_date) = 1968 and Month(meas_date) = 2 OR Month(meas_date) = 3 OR <br />Month(meas_date) = 4 <br />Dawson Aquifer <br />SPDSS Phase 3 Task 44.2 TM -Final A-1 <br />11/28/06 <br />