Your Water
Edwards Aquifer - Recharge Initiative
Giving Mother Nature a Helping Hand
The recharge initiatives project involves forcing additional stream flows into the Edwards Aquifer. Two types of recharge structures either on or above the recharge zone are being reviewed by SAWS for possible use:
- Type I structures built above the contributing zone to hold back storm runoff before releasing it slowly across the recharge zone to seep more water into the aquifer.
- Type II structures built directly over the recharge zone to impound storm runoff, then allowing it to recharge directly into the aquifer. SAWS has identified Type II structures for further analysis.
Conducted by the U.S. Army Corps of Engineers (Corps), SAWS has authorized two studies, the Cibolo Watershed Study (Cibolo Study) and the Nueces River Basin Study (Nueces Study), both of which are currently underway. The Recharge and Recirculation Study, an additional study in cooperation with the Edwards Aquifer Authority (EAA) that contains potential projects relating to recharge structures, was completed in December 2008.
Cibolo Watershed Study
The first study SAWS commissioned to the Corps was the Cibolo Watershed Study, a watershed approach to ecosystem restoration and flood damage reduction. The potential recharge structures contained in this study are included as ecosystem restoration. Recharge to the Edwards Aquifer is considered ecosystem restoration due to the beneficial impact to Comal Springs. However, depending on the final location of the proposed recharge/flood reduction structures, the Trinity Aquifer also could benefit with increased recharge. In either scenario, the San Antonio region would benefit.
Cibolo Study Sponsors – Corps, San Antonio River Authority, Guadalupe-Blanco River Authority (includes partnership with Edwards Aquifer Authority), SAWS
Timeline – Three-phased study, from 2002 through 2011; currently in Phase III
Nueces River Basin Study
The Nueces Study is the largest and most comprehensive study in cooperation with the Corps. The scope of this multipurpose feasibility study represents a holistic approach to address Nueces River Basin ecosystem restoration, flood control, aquifer recharge, water supply, water quality, brush management and overall watershed resource management. Collectively, these components are expected to function as a system and are designed to accomplish the following goals:
- Restore ecosystems of the Nueces River delta through increased freshwater inflows
- Increase volume and reliability of spring/base stream flows via aquifer recharge enhancements for the benefit of endangered species and water supply for communities dependent on the Edwards Aquifer.
- Reduce damages associated with flooding events in the basin.
There are four potential recharge structure sites identified in the Study, all located in the Edwards recharge zone.
Nueces Study Sponsors – Corps, Nueces River Authority, City of Corpus Christi, San Antonio River Authority, Guadalupe-Blanco River Authority, SAWS
Timeline – Three-phased study, from 2004 through 2012; currently in Phase II
Recharge and Recirculation Study
A continuation of the Recharge and Recirculation Study (R&R) originally undertaken by the EAA, Phases III and IV include the following: evaluation of potential operational parameters and water sources, and costs for various R&R scenarios. The primary goals of R&R are to evaluate the feasibility and estimated costs to increase the overall storage of water in the Edwards Aquifer in order to increase firm water supply and ensure adequate spring flow.
Completed in December 2008, the study suggested a number of recharge or recirculation components that could be further evaluated to determine their feasibility to provide additional recharge to the Edwards. Additional studies are currently being discussed as a possible management strategy by the Edwards Aquifer Recovery Implementation Program, a regional stakeholder group working with U.S. Fish and Wildlife Service to develop a program to ensure springflows and maintain the endangered spring species.
R&R Study Sponsors – Edwards Aquifer Authority and SAWS
