The cities of El Paso and Juarez lie on opposite sides of the U.S.-Mexico border, but they share the same ecosystem and water supply challenges. Now, the two are coming up with innovative ways to stretch their water resources.

The cities lie within the Chihuahuan Desert ecosystem and are separated by the Rio Grande, which forms the border between Texas and northern Mexico. Both communities have seen growing populations and are struggling to meet demand as water sources are increasingly taxed.

Climate change is expected to further shrink supplies in a region that receives 7 to 10 inches of rain per year. The Rio Grande Basin will likely see a 10 to 20 percent decrease in streamflow by the middle of the century, said University of New Mexico professor David Gutzler during a binational water resources conference held in Juarez and El Paso late last month (Greenwire, Oct. 1).

Those dire predictions are forcing the cities, both of which have relied primarily on shared aquifers thus far, to diversify their water portfolios to include desalination, conservation and reuse of water.

Increasing pressure on the aquifers has caused them to shrink, said Rene Franco, who serves on the city of Juarez's water board. "The transboundary aquifers that we're using are very overexploited," he said.

Meanwhile, the area continues to attract more residents.

"We've seen our population double in the past 50 years," added David Torres of El Paso Water Utilities, which provides 90 percent of El Paso's water. "Going forward, we expect we'll continue to see our population grow. And as it grows, meeting our water needs is very important."

Water to support continued economic development is of particular importance for Juarez, where incomes are much lower than in El Paso and unemployment rates are higher, said Ian Brownlee, the U.S. consul general in Juarez.

"We have lots of people; we have a strong industrial base," he said. "What we don't have is a lot of water. We need it to thrive, survive and grow. We share the same water and the same air. We need to find the most appropriate ways to share our resources."

Drought has upped the ante and is the biggest challenge El Paso water managers now face, said Ed Archuleta, president and CEO of El Paso Water Utilities.

The Elephant Butte Reservoir in southern New Mexico is 5 percent full -- "in other words, it's 95 percent empty," he said. "A lot of people are not aware of how serious it is."

The reservoir stores and releases Rio Grande water for use by irrigators and municipalities downstream. This year, El Paso received about 37,000 acre-feet of water from it, compared to 60,000 acre-feet in a normal year, Archuleta said.

Runoff into Elephant Butte, which comes from melting snowpacks in southern Colorado and northern New Mexico, has been above average for three of the past 16 years, Archuleta said. "That means less storage and of course less water available to the river," he said.

A long-term plan

Water officials in both El Paso and Juarez say that to ensure a sustainable water supply -- and a sustainable economy -- into the future, long-term planning is essential.

Torres of El Paso Water Utilities credits the city's water resource management plan, which lays out how it will meet water needs over the next 50 years, for putting El Paso on the right course. Under the plan, the city relies on a mix of surface water, groundwater, desalination and conservation.

"There's no community across the world that can survive without a sustainable, long-term water management plan, and our community is no different," he said.

Taking pressure off the aquifers, which underlie portions of Texas, New Mexico and the Mexican state of Chihuahua, will allow El Paso to increase groundwater pumping during times of drought, when river flows drop, added Torres.

"Groundwater is an important part of our portfolio during drought," he said. "[We] drilled new wells to give us the capacity we need when surface water is less than anticipated."

The utility has worked with the local irrigation district and the Bureau of Reclamation, which operates Elephant Butte Reservoir, to acquire water rights.

Desalination also has done much to help stretch supplies, Torres added.

"It's played a huge role in our water portfolio strategy," he said. "During the drought we currently face, we were able to use it at full capacity. There were no issues, and it allowed us to serve the needs of our community."

Treating salty water so that it is usable also allows El Paso to put off importing water, an expensive and complex option, he added.

"We're saving residents about a billion dollars and can delay importation," he said. "We used to think it would occur in 2040, but because of desal and conservation, we're now looking at 2050."

In the future, the city hopes to use treated water to replenish the aquifer, he added.

"We have a little bit of a different strategy than other communities," Torres said. "We're very optimistic about the future of El Paso and for the future of growth."

El Paso's diversified approach to water management is paying off, Archuleta said.

"What we've seen in our wells is they've stabilized," he said. "The conservation ordinance, the investment in additional surface water rights and treatment capacity, investing in wells, has all benefited us. We have basically embraced technology to allow us to accomplish this."

Across the river, water managers in Juarez are also trying to stretch supplies, but in different ways.

This year, the city started using a new aquifer, taking pressure off the old one, which is overtapped, Franco said. Water managers have also implemented conservation measures, resulting in a drop in municipal water use from 400 liters per day to 285 liters per day, he added.

"We're trying to decrease exploitation of this resource," much as El Paso has, he said.

Juarez also has focused on using reclaimed water to get the most out of every drop. The city now has several sewage treatment plants that allow water to be reused for landscaping and irrigation and is building a new one. The plants were financed in part through U.S. EPA funding.

"With all these plants, we'll be able to treat all of the wastewater in Juarez," Franco said.

The two cities are exchanging information and exploring other ways to work together to ensure that both can sustain growth into the future, Archuleta said.

"Regional water planning has been a success and must continue," he said.

Reese writes from Santa Fe, N.M.