Water From a Stone: The Limits of the Sustainable Development of the Texas Edwards Aquifer




Votteler, Todd Haydn

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A conflict over protection of threatened and endangered aquatic species has established the limits on the sustainable development of the Edwards (Balcones Fault Zone) Aquifer in south central Texas as the minimum discharges from Comal Springs in New Braunfels, Texas, and San Marcos Springs, in San Marcos, Texas. This conflict is aggravated by periodic droughts that increase the demand for water, while reducing recharge. This research demonstrates that in the fall, critically low spring discharge conditions can be predicted for the following summer allowing water conservation measures to be initiated in advance of critical periods. Conventional drought indices such as the Palmer Drought Severity Index and the Standard Precipitation Index were found to be unreliable indicators of hydrologic drought in the Edwards Aquifer region. Regional drought management plans have attempted to restrict pumping from the aquifer based on changes in the levels of three regional groundwater index wells. This research determines that the levels of the groundwater index wells are poor proxies for spring discharge rates, necessitating the revision of regional drought management plans. In addition, it was determined that the aquifer can be more sustainably managed by diverting excess spring discharge during wet periods for storage to be used during droughts and periods of low recharge to reduce water demand from the aquifer. A system for storing excess spring discharge called the San Antonio Drought Reserve Project is proposed.



Edwards Aquifer, sustainable development, groundwater, law and legislation, groundwater management, water rights


Votteler, T.H. (2000). Water from a stone: The limits of the sustainable development of the Texas Edwards Aquifer (Unpublished dissertation). Southwest Texas State University, San Marcos, Texas.


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