Oklahoma Water Resources Board the Water Agency
skip nav rules forms FAQs reports board meetings OCWP
site map help
water quality
water supply & availability
water & wastewater financing
technical studies
· groundwater
· surface water
· water quality
· legislative
hazard mitigation
data & maps
about us

Oklahoma Comprehensive Water Plan


Vulnerability Assessment of Twelve Major Aquifers in Oklahoma

Technical Report 98-5

September 1998

Prepared by
Oklahoma Water Resources Board

vulnerability assessment aquifers


The Oklahoma Water Resources Board (OWRB) and U.S. Geological Survey (USGS) conducted a vulnerability assessment of 12 major Oklahoma aquifers using the EPA's DRASTIC index method. Twelve major aquifers, for which adequate data were available from previous studies, were selected for the study: six bedrock aquifers (Central Oklahoma, Vamoosa-Ada, Rush Springs, Antlers, Elk City, and High Plains) and six alluvium and terrace aquifers (Enid Isolated Terrace, Tillman Terrace, Cimarron River, and three segments of the North Canadian River--the western reach from the Panhandle to Canton Lake, central reach from Canton Lake to Lake Overholser, and eastern reach from Oklahoma City to Eufaula Lake).

DRASTIC was developed by the EPA to be a standardized system forevaluating groundwater vulnerability to pollution. The method considersseven hydrogeologic factors: Depth to Water,Net Recharge, AquiferMedia, Soil Media, Topography, Impactof the Vadose Zone Media, and Hydraulic Conductivityof the Aquifer.

The USGS created, documented, and published digital geospatial datasets that describe the aquifer characteristics and created the gridlayers used to calculate the DRASTIC index. The OWRB used the gridlayers created by the USGS to compute the final DRASTIC indices andto produce the aquifer vulnerability maps. The maps were based ona cell size of 960 x 960 meters, or about 228 acres.

Figure 1. Drastic Aquifer Vulnerability Map of the 12 Major Aquifers
Figure 1. Drastic Aquifer Vulernability Map of the 12 Major Aquifers

The resulting aquifer vulnerability maps (Figure 1.) indicate that of the 12 major aquifers included in the study, the bedrock aquifers are the least vulnerable to contamination from pollutants introduced at the ground surface, and the alluvium and terrace aquifers are the most vulnerable. The High Plains aquifer is only moderately vulnerable, largely due to its great depth to water.

Many documents available on this site are in Adobe® Acrobat (.PDF) format and require the free Adobe® Reader software to view and print.
Visit www.ok.gov, the Oklahoma State Portal
©1998-2023, Oklahoma Water Resources Board
Page last updated: December 11, 2020

This site has been redesigned using Cascading Style Sheets (CSS). If you are seeing this message you are using an older browser which lacks support for CSS. Please upgrade your browser to the latest version of Internet Explorer, Netscape or other CSS compatible browser to view this page properly.