New water technologies explored to meet future demand

As demands on Texas’ water supply increase along with the state’s population, communities are seeking innovative solutions to provide water. Among the proposals are the development of aquifer storage and recovery (ASR) and desalination of brackish groundwater. ASR is a way to store drinking water underground in existing aquifer formations, while desalination is the treatment of brackish water or saltwater to drinking water standards.

This interim, the House Natural Resources Committee is charged with examining strategies to enhance use of ASR projects, including reviewing existing facilities and examining methods to facilitate further development of brackish groundwater. The Senate Natural Resources Committee is charged with studying ways to encourage the use of brackish water, not limited to ASR and desalination.

Twin Oaks facility

Image provided courtesy of San Antonio Water Systems (click to enlarge)

An example of an ASR project is the Twin Oaks facility in southern Bexar County, which covers more than 3,200 acres over the Carrizo-Wilcox Aquifer and provides drinking water to San Antonio. San Antonio Water System (SAWS) also uses the facility to pump water from the Edwards Aquifer, the city’s main water source, into a compacted sand formation in the Carrizo Aquifer in the winter when the Edwards is high. It is removed in the summer when the Edwards is low.

On a recent tour for lawmakers, staff, and other interested parties, SAWS officials said the Twin Oaks ASR facility can store one third of the city’s annual demand underground. A new study by SAWS  suggests it could double to hold 200,000 acre-feet as a reserve when the Edwards Aquifer is low. SAWS is building a desalination plant at the Twin Oaks facility designed to pump brackish groundwater from the deeper, more saline Lower Wilcox Aquifer for treatment and eventual storage.

Some have called for regulatory reform to accompany development of new water technologies, specifically to establish ownership rights of water pumped underground and to provide regulatory certainty to facilitate use of desalinated brackish groundwater. For example, water producers have said that to ensure effective financing of large projects, permits for brackish water should be lengthened from five years to 20 or 30 years. Also, while El Paso Water Utilities, the City of Kerrville, and SAWS each have ASR projects and own the property over their stored water, some have called for regulatory reforms to provide more certainty about ownership of stored water, particularly in areas where the facility does not own the land.

In 2013, the 83rd Legislature considered HB 3013 by Larson, which would have established a legal and regulatory framework for ASR and expedited the permitting process for ASR projects. Among other provisions, it also would have established the role of groundwater conservation districts in such projects, particularly with respect to stored water. Supporters of the bill said that existing ASR facilities had shown they were feasible using different sources of water and in different types of aquifers and that HB 3013 would help facilitate more widespread use of the technology. Opponents of the bill said that while ASR development might be warranted, the bill would provide for a “one-size-fits-all” set of model rules for groundwater conservation districts statewide, which was not appropriate for aquifers that vary so much around the state. They also expressed concerns about requiring the Texas Commission on Environmental Quality to approve the injection of treated wastewater as part of an ASR project. HB 3013 passed the House and died in the Senate Natural Resources Committee.

HB 2578 by Larson, also considered by the 83rd Legislature in 2013, would have directed the Texas Water Development Board to identify aquifers or portions of aquifers to be designated as brackish groundwater production zones suitable for the development of large-scale desalination projects. It also would have provided 30-year permits for pumping brackish groundwater with no production limitations.  Supporters of the bill said it would provide regulatory certainty and access to a long-term supply of water while maintaining local control of groundwater planning and regulation. They said it would protect existing fresh groundwater supplies by allowing permits to be amended if pumping brackish groundwater was having a negative impact on the fresh groundwater supply. Opponents of HB 2578 said it would create an inappropriate “one-size-fits-all” approach for aquifers that vary around the state. They said that despite safeguards, negative impacts to fresh groundwater could be irreversible by the time they were identified. HB 2578 passed the House and died in the Senate Natural Resources Committee.

by Blaire Parker

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