Design in a Time of Uncertainty
By Rives Taylor, Principal, Global Resilience Research Lead
Memories of 2011’s brutal heat wave and awareness of continuing drought conditions in many areas of the state were evidently on many Texas voters’ minds last November. Responding to bipartisan appeals to do so, they overwhelmingly approved a $2 billion allocation from the state’s Rainy Day Fund for water-supply and water-conservation projects under the State Water Plan.
In keeping with HARC’s commitment to provide its considered scientific advice to policy-makers on such matters, HARC President Jim Lester has been publicly voicing his view that Texas needs to pursue a different approach to water issues than it has in the past, when projects such as new reservoirs to collect and store surface water traditionally and consistently took precedence.
“My concern is that we will spend a lot of that money [approved by the voters] on reservoirs that we already know won’t provide a lot of water security because of evaporation,” he said.
Instead of charging ahead with approval for new reservoir projects included in the Water Plan’s most recent blueprint for meeting the water needs of Texas’ rapidly growing population, Lester believes officials should focus on “how to optimize the money that we’ve got for a more secure water supply in the future.”
Specifically, he said, a smarter, more scientifically-grounded approach will assign the highest priority to water conservation projects as it also greatly increases consideration and funding of innovative water-supply projects.
Topping the list of innovative concepts that Lester recommends is the storage of water underground – a technology that eliminates the water losses associated with reservoir evaporation, which are especially vexing during the state’s hot, dry summers. Climate scientists project the state’s summer months will generally get even hotter and drier in decades ahead with the global warming trend.
In a recent column that he wrote for the Houston Chronicle, Lester spelled out the reservoir problem in terms of the situation experienced in Central Texas during the record-setting summer heat-wave and drought conditions three years ago:
Major reservoirs are the most expensive items in the Texas Water Plan, but as evidenced in the recent drought, they prove quite ineffective for providing water security during periods of extremely low precipitation. Data show that during 2011, evaporation loss from Lakes Travis and Buchanan was actually greater than the amount of water used by the city of Austin.
In Lester’s view, the “clear alternative” to reservoirs is storing water underground. Texas cities including San Antonio and El Paso already do that, as do water utilities in other states including Florida, California and Nevada.
In the State Water Plan’s latest edition, issued in 2012, however, the “recommended water management strategies” for the period leading to 2060 include “new major reservoirs” representing 16.7 percent of the total volume while underground “aquifer storage and recovery” accounts for a scant 0.9 percent.
Underground storage, often employed to meet summer demands, “is feasible only in certain formations and in areas where only the utility owning the water can access it,” the Water Plan says.
But in his Chronicle column, Lester noted that “there is vastly more capacity for underground storage than there is land for good, viable reservoir construction in Texas.”
Underground storage, he explains, has not been employed in Texas to a wider extent because the “right of capture” in state water law means some water providers that might adopt such plans are fearful that other potential users nearby might pump it out for themselves.
San Antonio dealt with this possible problem by securing ownership to several thousand acres of land – and the water rights underneath. But while that’s a better approach than building a surface reservoir, those who choose underground storage should be legally assured that if they pump a certain amount of water underground for later use, it belongs to them, Lester said.
HARC hopes to collaborate with university-based researchers to help answer crucial questions surrounding some of the technical issues that must be confronted in order to expand underground water storage in Texas.
To evaluate the potential for such projects in different regions, experts will have to match an area’s water demand with the available storage space in neighboring geological formations. At the same time, they must match the chemistry of the surface water being collected and stored with the chemistry of the groundwater already present there, Lester said.
Without making sure the chemistry of the stored water is a proper fit for the already-underground water, project planners run the risk of introducing unwanted contaminants to a groundwater formation. Done right, however, an underground storage project offers the dual advantages of forgoing an evaporation-prone reservoir and advancing water conservation at the same time.
“El Paso takes treated wastewater and injects it underground to store it for reuse,” Lester noted. If that approach were more broadly used it Texas, it “would combine the two things I want to emphasize – conservation and underground storage. If you’re spending that kind of money to treat wastewater and you use it for your water supply, you’re going to be pretty careful about wasting it.”
The Texas Legislature last year directed the Water Development Board, the agency that oversees spending on water projects, to dedicate at least 20 percent of the $2 billion approved by voters to “conservation and reuse” proposals. Some conservation advocates supported the ballot measure because of that directive, though others opposed it out of concern that the legislative instruction was too vague and therefore might not prove binding as the board selects the projects to fund over coming years.
One potential pitfall for conservation that Lester sees is the State Water Plan’s shortage of specifics about water-saving projects in contrast to the numerous details provided for water-supply reservoirs and pipelines.
The Water Development Board is expected to move ahead this year with selections of the initial projects to receive funding from last year’s $2 billion allocation. Meanwhile, regional water planners will be working on their recommendations, to be submitted in 2016, for possible inclusion in the next edition of the State Water Plan.
As this continuing process unfolds, “I want to see real hard scrutiny given to reservoir projects and a lot more emphasis on underground storage and a lot more detail on exactly what projects you’re going to do to achieve the (20 percent) conservation goal,” Lester said. “Right now, there’s just a lot of hand-waving about conservation.”