El Paso used to rely exclusively on the Rio Grande for its water. But the vulnerability associated with the city’s overreliance on the river became painfully clear starting in the late 1940s during the state’s drought of record. By 1951, the city’s water department warned that the river would not provide enough water to meet demand. The resulting evolution in the city’s “diversified water-supply portfolio” was recently presented by Scott Reinert at the Texas Ground Water Association’s Geoscience Seminar this past February in Alpine. Reinert is the water resources manager for El Paso Water, the city’s municipal water utility.
The primary solution identified in the 1950s was “to pump more groundwater” locally, according to Reinert, “but this was found to be unsustainable.” In addition, the utility’s flat-rate fee structure had nurtured a culture of excessive water use perhaps best exemplified, asserts Reinert, by a local newspaper’s “Best Citizen” contest intended to reward the person “who had the greenest yard.”
In order to address the water shortfall, El Paso sought to import groundwater from neighboring New Mexico in the 1970s, an approach that New Mexico adamantly refused. The ensuing lawsuit became known as City of El Paso vs. Reynolds, in which the Supreme Court ultimately backed New Mexico. This fateful ruling “fundamentally changed our approach to water in El Paso,” explains Reinert, and ushered in “the era of conjunctive use.”
“[C]onjunctive use refers to the coordinated and planned use and management of both surface water and groundwater resources to maximize the availability and reliability of water supplies,” according to the California Department of Water Resources. “Managing both resources together, rather than in isolation, allows water managers to use the advantages of both resources for maximum benefit.”
El Paso’s conjunctive-use approach initially involved building the capacity to treat up to 60,000,000 gallons per day of Rio Grande water “when the river is flowing,” according to Reinert. The next step involved the development of well fields in the area’s two local aquifers, the Mesilla Bolson and the Hueco Bolson, to sustainably produce groundwater when river supplies run low. These wells were drilled closely together, but to “different depth horizons,” so they “don’t compromise each other’s production,” explains Reinert.
Another facet of the utility’s water strategy emerged because military officials worried about the city’s ability to reliably supply water to Fort Bliss. This resulted in a collaborative effort to construct “the largest inland desalination plant in the world,” reports Reinert. The plant can process up to 27 million gallons per day of brackish groundwater containing about 4,000 milligrams of total dissolved solids per liter. This is “water that you wouldn’t want to drink,” explains Reinert. But the plant uses reverse osmosis to create “an ultrapure permeate” that is then blended with “naturally brackish groundwater” to arrive at a “finished water quality very similar” to the other potable water in the utility’s system.
Further innovations include the utility’s advanced water purification process to treat effluent to drinking-water quality and infiltrate it into the Hueco Bolson using an engineered arroyo with seven surface basins. Although these basins essentially constitute an aquifer storage and recovery project—a method opposed by the state’s retrograde regulatory authorities and currently prohibited in Texas. El Paso is using its existing wastewater permit to authorize the discharge of this potable-grade water to safely recharge the aquifer.
The last major arm of the utility’s conjunctive-use strategy is also its most controversial: a pipeline to export groundwater from the Bone Spring-Victorio Peak aquifer underneath Dell City in northern Hudspeth County. The project involved the purchase of just about all the groundwater in and around Dell City and is slated to begin delivering up to 10,000 acre-feet per year in 2050, according to Reinert.
All of these approaches will come at a cost, which means that water will almost certainly grow more expensive for El Paso residents. According to reporting by Diego Mendoza-Moyers for El Paso Matters, “[I]t costs El Paso Water something like $150 to pump an acre-foot of fresh groundwater. … Drawing and treating an acre-foot of surface water from the Rio Grande costs around $300. And an acre-foot of desalinated water costs the utility about $500 to produce. Meanwhile, the advanced water purification process that El Paso Water plans to rely more on in the future costs $1,000 per acre-foot of water produced … [a]nd piping water from Dell City … will cost around $3,000 per acre-foot.”
While expensive water is better than none at all, users can lower their bills by using less. “We incentivize our customers to conserve,” explains Reinert, by employing every tool in the “water conservation toolbox.” These tools, which include residential rebate programs, smart timers for watering, grey water use, and turf removal, have enabled El Paso to drastically reduce water use from 205 gallons per capita per day (GPCD) in 1985 to 131 gallons GPCD in 2023.
Based in an arid city with little choice but to adapt, El Paso Water has transformed itself into a model utility in response to the many challenges posed by growth and drought. As CEO John Balliew explained to El Paso Matters, the goal is to use all the resources available to become “drought-proof as a community.”
Visit epwater.org to learn more.