Now Part of the Region L’s Water Management Strategy
 rackish groundwater developed close to San Antonio could provide SAWS with a potential new source of water. Up to 22,000 acre-feet* per year could be made available to our water supply and help offset peak demands during the summer months.
Project Overview
A desalination project can be composed of seawater desalination, brackish groundwater desalination, or a combination of the two different sources. SAWS is currently studying these types of projects and other general plans. Neither a definitive location nor a desalination method has been identified in the Water Resources Plan. Conceptually, desalination water plants as small as 1 million gallons per day (mgd) to plants larger than 100 mgd have been reviewed. Desalination is included as a water management strategy in the Region L Plan.
Brackish Groundwater
Based on information from the Texas Water Development Board, the South Texas region has substantial brackish groundwater resources. Desalination water plants are being explored for development in the vicinity of Bexar County in either the Wilcox Aquifer and/or the Edwards Aquifer brackish water zones. These plants could range from 10 mgd to more than 20 mgd (or 11,000 acre-feet/year to over 22,400 acre-feet/year), depending on results from a feasibility study that will identify whether each aquifer can provide a sustainable water source.
An important consideration in the development of any water supply project includes cost and how the project will be procured. New legislation now supports the use of the design/build procurement method to develop new water supply projects. The design/build method offers cost savings to ratepayers and reduces substantial project time for those select to use this method. SAWS Brackish Groundwater Desalination project is consistent with plans outlined by the South Texas Regional Water Planning Group (Region L). Within the Region L plan, both large and small brackish groundwater desalination plants are suggested as possible supply alternatives to meet future regional water demands.
Project Development
In 2005, the SAWS Board of Trustees directed staff to begin development of a brackish groundwater facility that could produce between 10 and 20 mgd of water. A project of this magnitude involves the planning of a well field and collection system, a reverse osmosis treatment plant, transmission pipeline, and concentrate management plan. Feasibility work on this project was initiated in January 2006 when SAWS began investigating the use of water from the brackish formations in the Wilcox and Edwards aquifers. The initial step of the feasibility study was to identify and drill several test sites in these formations. Data from these test sites will assist SAWS in determining if such a project is feasible. SAWS’ goal is to have this project in production by mid-2011.
Extensive planning will be required to determine the plant’s location to keep the water source relatively close to San Antonio and consider the best method for by-product concentrate disposal. Using a design/build firm is one option that could reduce SAWS’ cost for a brackish groundwater plant.
* An acre-foot of water is equivalent to 325,851 gallons
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