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Conservation in San Antonio is Saving More than Water

Who would believe that a translucent sightless amphibian that dwells only in dark underground caves could force a big Texas city to not only slash its water use but make water waste illegal? But the rare, four-inch Texas blind salamander has done pretty much just that – and spawned an unusual water story in San...

Who would believe that a translucent sightless amphibian that dwells only in dark underground caves could force a big Texas city to not only slash its water use but make water waste illegal? But the rare, four-inch Texas blind salamander has done pretty much just that – and spawned an unusual water story in San Antonio, where impressive conservation efforts are now being tested by one of the worst droughts in memory.

While most Americans can’t even name the source of their drinking water, many San Antonians know not just their water source – an underground limestone formation called the Edwards Aquifer– but its height above sea level. That’s because that level, which is posted every day on the city water authority’s website, determines whether they can sprinkle their lawns — and whether the water police are likely to be out in full force.  Recently the Edwards level has measured between 640 and 650 feet, which means that residents can irrigate only once a week. If the aquifer’s level drops below 640 feet, the city will declare Stage 3 Drought and allow landscape watering only every other week.

So what’s all the fuss about the level of the Edwards Aquifer?  Enter the Texas blind salamander.

By the early 1990s heavy pumping from the Edwards had substantially reduced flows in San Marcos and Comal Springs, which harbor seven unique and endangered species, including the fountain darter, the Comal Springs riffle beetle, the Texas blind salamander, and Texas wild rice.  These species are found nowhere else in the world, so their local extinction from these aquifer-fed ecosystems would mean their exit from the planet.  The Sierra Club and others filed a lawsuit under the federal Endangered Species Act to limit pumping so as to sustain flows to the springs.  In response, the Texas legislature established the Edwards Aquifer Authority, which is charged with enforcing a cap on pumping that will keep the springs flowing and the species’ habitats intact.

Texas wild rice, an aquatic grass, is found nowhere in the world other than a small segment of the San Marcos River, which is sustained by the Edwards Aquifer. Photograph by Sandra Postel

Last week, I met with the talented team at the San Antonio Water System (SAWS) that is responsible for figuring out how this south-central Texas city can grow and thrive while living within these water limits.  While focused intensely on the current drought, SAWS is aggressively tapping water conservation, wastewater recycling and groundwater recharge as long term solutions to their water dilemma.

“We try to do one billion gallons of proactive permanent savings per year,” said Karen Guz, San Antonio’s energetic director of water conservation.

Guz lists a few dozen water-saving incentives and measures that she and her year-round staff of twenty-five push forward to relentlessly drive down water demand. These include large-scale commercial retrofits, a tiered water rate structure that doubles the unit price of water for the highest usage tier, irrigation check-ups for large properties, rebates of $400 per acre-foot for proven savings, and a highly successful toilet-replacement campaign.

Karen Guz directs San Antonio’s water conservation program. Photograph by Sandra Postel.

“We do a lot of potty training,” says Guz with a quick smile that belies her steely-eyed seriousness about water conservation.  Besides encouraging good toilet maintenance to avoid leaks, Guz’s team targets homes built before 1992, when federal efficiency standards for toilets took effect, and offers to replace old guzzlers that gulp five to seven gallons per flush with new dual-flush models that average just one gallon per flush. (Dual flush refers to two flush volumes, one for solids and another for liquids.)

When public doubt crept in about how effectively these high efficiency units would work, SAWS set up a demo toilet and filmed it flushing a four-inch Russet potato.  Two retired military officers showed up with their own potato, Guz recalled.  They said, “We want to see.”   They saw, and lined up for their toilets.

To date, SAWS has replaced one quarter million toilets.  Guz, of course, is fixated on the 100,000 older units still in place.  “That’s too much water to leave on the table.”

The water authority also works with farmers who use city water to irrigate their corn and other crops.  Though just a fraction of the system’s 1.3 million customers, farmers pump a lot of water during the peak summer season, and their irrigation practices can make the difference between a Stage 2 or Stage 3 drought declaration in a year like this one.

According to Mike Brinkmann, SAWS vice president for operations services, a farmer shifting from old-style flood irrigation to precision sprinklers can reduce water use by two-thirds.  SAWS might strike a deal to lease the saved water from the farmer or to pay for the irrigation upgrade in exchange for the water rights the farmer no longer needs– a win for the farmer, the city, and the Texas blind salamander.

The channel alongside San Antonio’s Riverwalk flows with recycled water. Photograph by Sandra Postel

Besides conservation, SAWS runs perhaps the nation’s largest direct water recycling system.  Up to 17 million gallons per day of treated wastewater is sold to golf courses, power plants, and other local businesses, including Toyota and Microsoft. In addition, up to 100 million gallons a day of recycled water gets released to the San Antonio River.  Since the river’s natural flow stops when the Edwards Aquifer drops below 670 feet, the river’s entire flow in summer can consist of recycled water, as it did when I paid a visit to its banks in Brackenridge Park last week.  An outflow pipe was discharging a hefty volume of flow into the channel.

The San Antonio River in summer consists of recycled water, which here is getting discharged into the channel. Photograph by Sandra Postel.

“We consider the river one of our customers,” said Meg Conner, SAWS director of environmental services. Recycled water also makes up most or all of the flow along San Antonio’s famous Riverwalk, which winds through the downtown and attracts hoards of tourists each year.

All of these measures add up.  Since 1984, San Antonio’s total per capita water demand including residential, commercial and industrial uses – has dropped 42 percent.

In many ways, the city’s ace-in-the-hole strategy – and perhaps the savior of the Texas blind salamander and its other endangered compatriots – is its $250 million Aquifer Storage and Recovery System. To avoid pumping the Edwards too low during dry periods, the city pumps more than it needs during wet periods, when the aquifer level is high, and stores that “surplus” in the shallower, lower-quality Carrizo Aquifer.  The city then taps this bubble of stored Edwards water for use during dry spells.  Conservation director Karen Guz calls it “ saving for a drier day.”

At the moment, SAWS has about 97,000 acre-feet of Edwards water stored in the Carrizo, about half of the city’s annual water demand.  Last week, water managers were pulling 40 million gallons a day out of storage to meet 20 percent of the city’s daily water demand.  So this “dry day fund” is helping the city avoid a Stage 3 drought declaration and keeping the springs flowing for the fountain darter, riffle beetle, blind salamander and other species skating on the brink of extinction.

For the past four years, the city, farmers, environmental groups and other stakeholders of the Edwards Aquifer have been negotiating a “habitat conservation plan” to assure federal officials that future pumping from the Edwards will not destroy the species’ habitats.  Nearing completion, the plan is expected to cost $20 million a year to implement, with the aquifer storage and recovery scheme accounting for 60 percent of that total.

During my final hours in San Antonio, I headed out of town for a look at the springs at San Marcos.  There I saw the little blue jewel of south-central Texas called Spring Lake, which is fed entirely by the springs that also sustain the endangered species hanging in the balance.  And I couldn’t help but feel that the lowly, pigment-less, blind salamander with the broad head and flattened snout has done San Antonio a huge favor.  From the quiet darkness of the limestone caves it calls home, this most uncharismatic amphibian has connected an entire city to its source of water and the amazing variety of life it sustains.


Sandra Postel is director of the Global Water Policy Project and lead water expert for National Geographic’s Freshwater Initiative.  She is the author of several acclaimed books, including the award-winning Last Oasis, a Pew Scholar in Conservation and the Environment, and one of the “Scientific American 50.”

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Meet the Author

Sandra Postel
Sandra Postel is director of the Global Water Policy Project and author of Replenish: The Virtuous Cycle of Water and Prosperity. From 2009-2015, she served as Freshwater Fellow of the National Geographic Society. Sandra is also co-creator of Change the Course, the national water stewardship initiative awarded the 2017 US Water Prize for restoring billions of gallons of water to depleted rivers and wetlands. The recipient of several honorary degrees, she works to bridge science, policy, and practice to promote innovative ways of securing water to meet both human and ecosystem needs.