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

The WELL_MEAS table contains the water level measurement data for wells. This table is
linked to the WELLS table by the well_id field. The WELL_MEAS table contains the
measurement date, measuring point height, and the depth to water for each measurement. The
ground surface elevation in the WELLS table allows the water level elevation to be calculated.
The REF_LOC_ACCURACY table includes comments on the siting accuracy of the location
(X,Y) data.
The REF_ELEV_ACCURACY table includes comments indicating the source and accuracy of
the elevation value.
2.2 Database Quality Control
A series of quality control steps were undertaken once the data were compiled into a common
electronic format. These steps were performed to check accuracy of the data before submitting it
to the State for uploading into HydroBase.
Numerical data from each of the sources identified in Section 1.1 were initially entered into a
Microsoft Excel® spreadsheet. The data were then checked for accuracy by comparing the
entered data to the original hard copy data. New data received in electronic format were
checked with the original database for data importation/data entry accuracy on a 10-percent
quality control frequency. If errors in the data entry were found then 100 percent of the data
from that data source was checked. The spreadsheet was then exported to the HydroBase-
compatible SPDSS database. This procedure was used to assure quality for all data that was
added to the SPDSS database.
After the SPDSS database was checked for quality control purposes, it contained 6,754 unique
alluvial wells with over 108,843 alluvial aquifer water level measurements in the South Platte
Alluvium Region. It should be noted that the time periods selected in this TM for data
presentation represent a subset of these data.
3.0 Results
This section presents a summary of the water level data for the South Platte Alluvium Region.
The data are presented in plan-view maps of the water level surface at specified time periods, in
a trend map, and in hydrographs that depict water level trends over time at individual wells
located throughout the region.
The water level contours, database water level measurements, and control points presented in
this section will be provided in shapefile format to the DWR as part of this TM.
3.1 Water Level Surfaces
The six time periods selected for water level mapping and comparison were 1968, 1978, 1990,
2001, 2003, and 2005. The water level maps for the alluvial aquifer for these selected time
periods are shown in Figures 4 to 9, respectively. The contours shown on these maps were
generated using the data described in Section 1.4.
SPDSS Phase 3 Task 44.3 TM -Final 11
11/29/2006