E.V. Spence Reservoir: Implementing TMDLs for Total Dissolved Solids and Sulfate
Counties: Coke, Mitchell, Nolan
Parameters: Total Dissolved Solids (TDS), Sulfate
River Basin: Colorado River
Background and Goals
The E.V. Spence Reservoir is located in Coke County. With a surface area of 15,893 acres, it is an important source of water for more than 300,000 people in surrounding cities, including Big Spring, Odessa, Midland, and San Angelo. Additionally, the reservoir serves mining and industrial uses, and it is a popular destination for recreational fishermen. Water quality testing found that excessive levels of sulfate and total dissolved solids (salinity) are affecting the lake and its use for drinking water. The goal of this project is to reduce point and nonpoint sources of these pollutants to restore and maintain water quality standards for the reservoir.
To reduce salinity concentrations, the Colorado River Municipal Water District (CRMWD) has been managing diversions of fresh water from the Colorado River into the reservoir since 2001. Prior to the drought of 2010–2011, the levels of saline contaminants were dropping in E.V. Spence Reservoir and the watershed of the Colorado below it. However, due to persistent drought, water levels in the reservoir have dropped drastically. This, in turn, has led to concentration of chloride, sulfate, and TDS.
The Railroad Commission of Texas identified and plugged abandoned and orphaned oil wells to eliminate that source of pollution. As CRMWD finds new wells, they notify the Railroad Commission and work to plug them. The RRC also completed a study to evaluate other management practices that would reduce or prevent salinity in the streams that flow into the reservoir.
The commission adopted these TMDLs on June 14, 2002.
- Two Total Maximum Daily Loads for Total Dissolved Solids and Sulfate in the E.V. Spence Reservoir
- Response to public comment on the E.V. Spence TMDLs
The EPA approved these TMDLs on May 9, 2003, at which time they became part of the state's Water Quality Management Plan.
Updates to TMDLs
From time to time, it is necessary to revise TMDLs to account for changing conditions in the watershed, such as new or amended permits, or urban growth, or to correct oversights in the original TMDL report. Revisions to the load allocations in TMDLs are made via the state’s WQMP, which is updated quarterly.
The WQMP provides projected effluent limits for use in planning and permitting activities under the Texas Pollutant Discharge Elimination System (TPDES). The TCEQ reviews all applications for new and amended permits for conformance with applicable portions of the WQMP, including adopted TMDLs.
Revisions to the TMDL are documented in the approved WQMP updates listed below.
- July 2009 , Appendix III, page 10
The commission approved the Plan on August 10, 2001.
- Implementation Plan for Sulfate and Total Dissolved Solids TMDLs in the E.V. Spence Reservoir
- Response to public comment on the E.V. Spence Implementation Plan
For More Information
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