Groundwater Monitoring on Fort Sill Apache Tribal Lands Completed

Summary

            Caddo County and Comanche County, OK are underlain by several geologic formations, one of which is the Rush Springs sandstone. The Rush Springs sandstone aquifer is used as a reliable water supply for agricultural lands throughout its extent in west-central Oklahoma (Tortorelli, 2009). The Fort Sill Apache Tribe is interested in analyzing the groundwater supply potential of their trust lands in Caddo and Comanche counties.

            This USGS investigation will examine the hydraulic properties of the Rush Springs aquifer underlying Fort Sill Apache tribal lands to determine their potential for groundwater development. The information gathered from this investigation will assist the Fort Sill Apache Tribe in identifying well locations with optimal long-term pumping capacity and water quality.

Problem

The Fort Sill Apache Tribe has six plots of Tribal trust land available for potential groundwater development in Caddo and Comanche Counties, three of which lie atop the Rush Springs aquifer. Although these three plots are likely to yield groundwater, it is not clear which plot or plots would be best for long-term development.

Objectives and Scope

            The objectives of this proposed project are to provide data and information to the Fort Sill Apache Tribe about the hydraulic properties of the Rush Springs aquifer underlying specified Tribal trust lands in the Rush Springs aquifer.

Relevance and Benefits

            Collection and analysis of water-level data in the Rush Springs aquifer will provide a means for the Fort Sill Apache Tribe to better understand the groundwater hydrology of the Rush Springs aquifer in this area.  In the course of this project, the USGS will provide information that will reflect the availability and quality of the groundwater in the Tribal trust lands.

Approach

            An evaluation will be conducted of the wells in the vicinity of the three Tribal trust land plots that lie overtop the Rush Springs aquifer by analysis of the Oklahoma Water Resources Board Well Completion Database. Once it has been determined which wells are suitable and available for observation, transducers will be placed in these wells for water level monitoring. Water level monitoring data will be collected in these wells for a period of 12 months. In addition to analyses of any available water quality data, measurement of pH, specific conductance, dissolved oxygen concentration, and water temperature will be made for selected wells.

Continuous water-level information gathered from transducers, paired with nearby rainfall data, will determine effects on available groundwater from seasonal rainfall. The information from transducers can also be compared to nearby groundwater use to determine the effects from local withdrawals.