SPDSS_Task44-3_LowerSPlatteAlluviumRegionAquiferWaterLevels

• Title: SPDSS Task 44.3 - Lower South Platte Alluvium Region Aquifer Levels - Phase 3
• Description: This Technical Memorandum was undertaken under Task 44.3 of Phase 2 of the SPDSS, and summarizes the compilation, analysis and mapping of water level data of the South Platte Alluvial Aquifer.
• Decision Support - Doc Type: Task Memorandum
• Date: 11/29/2006
• DSS Category: Groundwater
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153953
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: CDM

Appendix A: Instructions to Query Water Levels from HydroBase for Contouring the South
Platte Alluvial Aquifer Water Level Surfaces
1.0 Purpose/Objective
To document the procedure used to query the water level picks from HydroBase for contouring the Phase
2 South Platte Alluvium Region water surfaces.
2.0 Procedure/Approach
The following procedure was used to query spring alluvial water level data from HydroBase:
1) In Microsoft Access, a table containing the aquifer codes assigned to wells in the WELLS table during
Phase 1, WELLS_DSS_AQUIFERS was imported into the database. This correlation table was supplied by
the State. A select query was defined to create two new fields DSSAquiferl and DSSAquifer2 by first using
the values reported in aquiferl and aquifer2 codes in WELLS_DSS_AQUIFERS and if those values are null,
using the aquiferl and aquifer2 codes in the WELLS table.
2) In ArcGIS a spatial query was performed to identify all wells located within the SPDSS South Platte
Alluvium Region study area (divl_alluvial_extent_20051010.shp) using a 2-mile buffer. The results of
this spatial query were used to populate a temporary lookup table, SPDSS_REGION. This table contains
the well_id and a new field, spdss_reg, indicating the well is located in the SPDSS study area. The table is
linked to the WELLS and WELL_MEAS table by the well_id field.
3) A query of the WELLS table was performed to identify any wells in the WELLS table with an
aquifer_commentnoting a USGS primary aquifer code that did not already have values for DSSAquiferl
and/or DSSAquifer2 fields and is located in the SPDSS study area. The USGS aquifer codes were
correlated to SEO aquifer codes.
4) In Microsoft Access, the WELLS, WELL_MEAS and SPDSS_REGION tables were linked via well_id
field. Selected fields were chosen from the WELLS table (location and aquifer information) and all fields
were chosen from the WELL_MEAS table. A query using the DSSAquiferl and DSSAquifer2 and
meas_date fields was used to identify the spring water level measurements for a well in a given year. The
query is depicted below.
South Platte Alluvium Region
a. DSSAquiferl = "QAL° AND DSSAquifer2 = Is Null AND SPDSS_REG = "SPDSS° AND
Year(meas_date) = 1968 and Month(meas_date) = 2 OR Month(meas_date) = 3 OR
Month(meas_date) = 4
The query results were exported to Excel.
5) In Excel, the first spring water level measurement in a given year was identified and included in the
dataset used for contouring.
6) Steps 4 and 5 were repeated for all time periods (1968,1978,1990, 2001, 2003, and 2005).
SPDSS Phase 3 Task 44.3 TM -Final A-1
11/29/2006