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Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015

Scientific Investigations Map 3378

Prepared in cooperation with the Lower Arkansas Valley Water Conservancy District
By:
https://doi.org/10.3133/sim3378

Links

  • Document: Report (1.25 MB pdf)
  • Plates:
    • Sheet 1 (8.02 MB pdf) Bedrock Altitude at the Base of the Alluvium of the Lower Arkansas River Valley, Southeast Colorado
    • Sheet 2 (17.1 MB pdf) Estimated Change in Water-Table Altitude, Spring-to-Spring, 2002–2008, 2018–2015, and 2002–2015; Fall-to-Fall, 2002–2008, 2018–2015, and 2002–2015; and Locations of Monitoring Wells in the Alluvium of the Lower Arkansas River Valley, Southeast Colorado
    • Sheet 3 (17.2 MB pdf) Estimated Saturated Thickness of the Alluvium, Spring 2002, 2008, and 2015; Fall, 2002, 2008, and 2015, and Estimated Thickness of the Alluvium in the Lower Arkansas River Valley, Southeast Colorado
  • Appendixes:
    • Appendix 1 (36.0 kB xlsx) Well Information and Measured Water Levels in the lower Arkansas Valley, Southeast Colorado, 2001–2015
    • Appendix 2 (572 kB pdf) Hydrographs Showing Water-Table Altitude in Select Monitoring Wells in the lower Arkansas Valley and Water-Surface Altitude in John Martin Reservoir, Southeast Colorado, 2001–2015
  • Data Release: USGS data release – Hydrogeologic Characteristics and Geospatial Analysis of Water-Table Changes in the Alluvium of the Lower Arkansas River Valley, Southeastern Colorado, 2002, 2008, and 2015
  • Read Me: Read Me (12.0 kB txt)
  • Download citation as: RIS

Abstract

The U.S. Geological Survey in cooperation with the Lower Arkansas Valley Water Conservancy District measures groundwater levels periodically in about 100 wells completed in the alluvial material of the Arkansas River Valley in Pueblo, Crowley, Otero, Bent, and Prowers Counties in southeastern Colorado, of which 95 are used for the analysis in this report. The purpose of this report is to provide information to water-resource administrators, managers, planners, and users about groundwater characteristics in the alluvium of the lower Arkansas Valley extending roughly 150 miles between Pueblo Reservoir and the Colorado-Kansas State line. This report includes three map sheets showing (1) bedrock altitude at the base of the alluvium of the lower Arkansas Valley; (2) estimated spring-to-spring and fall-to-fall changes in water-table altitude between 2002, 2008, and 2015; and (3) estimated saturated thickness in the alluvium during spring and fall of 2002, 2008, and 2015, and thickness of the alluvium in the lower Arkansas Valley. Water-level changes were analyzed by geospatial interpolation methods.

Available data included all water-level measurements made between January 1, 2001, and December 31, 2015; however, only data from fall and spring of 2002, 2008, and 2015 are mapped in this report. To account for the effect of John Martin Reservoir in Bent County, Colorado, lake levels at the reservoir were assigned to points along the approximate shoreline and were included in the water-level dataset. After combining the water-level measurements and lake levels, inverse distance weighting was used to interpolate between points and calculate the altitude of the water table for fall and spring of each year for comparisons. Saturated thickness was calculated by subtracting the bedrock surface from the water-table surface. Thickness of the alluvium was calculated by subtracting the bedrock surface from land surface using a digital elevation model.

In order to analyze the response of the alluvium to varying environmental and anthropogenic conditions, the percentage of area of the lower Arkansas Valley showing an absolute change of 3 feet or less was calculated for each of the six water-table altitude change maps. For fall water-table altitude change maps, the periods between 2002 and 2008, 2008 and 2015, and 2002 and 2015 showed that 86.5 percent, 85.2 percent, and 66.3 percent of the study area, respectively, showed a net change of 3 feet or less. In the spring water-table altitude change maps these periods showed a net change of 3 feet or less in 94.4 percent, 96.1 percent, and 90.2 percent of the study area, respectively. While the estimated change in water-table altitude was slightly greater and more variable in fall-to-fall comparisons, these high percentages of area with relatively small net changes indicated that, at least in comparisons of the years presented, there was not a large amount of fluctuation in the altitude of the water table.

The saturated thickness in the lower Arkansas Valley was between 25 and 50 feet in 34.4 to 35.9 percent of the study area, depending on the season and year. Between 30.2 and 35.6 percent of the area showed saturated thicknesses between 0 and 25 feet. Less than 1 percent of the area showed a saturated thickness greater than 200 feet in all mapped seasons and years.

Suggested Citation

Holmberg, M.J., 2017, Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015: U.S. Geological Survey Scientific Investigations Map 3378, pamphlet 9 p., 3 sheets, scale 1:130,000 and 575, 000, https://doi.org/10.3133/sim3378.

ISSN: 2329-132X (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Hydrogeologic Characteristics
  • Geospatial Analysis of Water-Table Change
  • References Cited
  • Appendix 1. Well Information and Measured Water Levels in the lower Arkansas Valley, Southeast Colorado, 2001–2015
  • Appendix 2. Hydrographs Showing Water-Table Altitude in Select Monitoring Wells in the lower Arkansas Valley and Water-Surface Altitude in John Martin Reservoir, Southeast Colorado, 2001–2015

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015
Series title:
Scientific Investigations Map
Series number:
3378
DOI:
10.3133/sim3378
Year Published:
2017
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Colorado Water Science Center
Description:
Report: vi, 9 p.; 3 Sheets: 43.0 x 32.0 inches or smaller; 2 Appendixes; Data Release; Read Me
Country:
United States
State:
Colorado
Other Geospatial:
Arkansas River Valley
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y