Drinkable seawater: Port Isabel to build desalination plant

Gary Long, The Brownsville Herald, Texas
·3 min read
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Jul. 26—With approval of a $10 million Texas Water Development Board loan, the Laguna Madre Water District will build a 10 million gallon seawater desalination plant in Port Isabel using water from the Brownsville Ship Channel.

The plant will be situated near water district offices in Port Isabel and draw water from the Gulf of Mexico near the Port Isabel Navigation District, LMWD General Manager Carlos Galvan said.

"We are excited about it. I've been working with Laguna Madre Water District for 37 years. We started piloting seawater in 1997 at the South Padre Island jetties and we know we can make drinking water out of the sea," Galvan said.

The loan is through the State Water Implementation Fund for Texas, or SWIFT, and will be used for planning, acquisition and plant design. The district will save $793,000 in interest over the loan's 30-year term, the Texas Water Development Board said in a news release.

Galvan said Laguna Madre voters approved a $15.6 million tax bond in 2011 to build a reverse osmosis seawater desalination plant. With the loan, the district will have an additional $5.6 million to work with during the design phase and will be able to build a 10 million gallon plant.

The plant will take three to four years to design and build. The eventual cost is projected at about $70 million. Voters approved up to 8 cents per $100,000 valuation to pay for the project, Galvan said.

"An environmental study has to be done, which is more stringent, to prove that nothing in the environment is going to be damaged, the wildlife, the aquatic life that's in the water. The next thing would be piloting, testing the water, six to nine months running the water through the plant and testing the water that's coming back out, which is the brine, or 50% salinity water, and 45-50% would be drinkable water," Galvan said.

The LMWD serves South Padre Island, Port Isabel, Long Island Village, Laguna Heights and Laguna Vista.

"We see that everything's growing in our area. It's growing at 2-3% per year and we need to make sure that we have enough water for the future," Galvan said.

"We see all the growth that's coming up, the drought that's hurting our water system, which is Falcon and Amistad lakes, now at 19.1%. It's been a long drought ... and that's making us move forward with the 2011 tax bond. There's also a feasibility study that needs to get done before we get started with the project," he said.

Galvan said the 1997 pilot project at the jetties, and another in 2008 at Beach Access No. 2, proved the technology works and were prompted by the district being the second to last to draw water from the Rio Grande.

Austin-based NorrisLeal LLC, which specializes in brackish and seawater desalination, is designing the plant, Galvan said. The firm designed the process Brownsville PUB uses at the Southmost Regional Water Authority plant to extract drinkable water from the brackish wells it owns in the area.

"We didn't want to go that route, so we're treating seawater, which is in our backyard, right here," Galvan said.

The district consumes 6.5 to 7 million gallons a day during the peak usage months of June, July and August, and 3.4 million gallons a day the rest of the year.

The desalination plant would probably be the first on the Texas coast, although Corpus Christi is working on one for industrial and commercial uses, Galvan said.

"Looking back at all of this, we know that we can get drinkable water from the sea, so the voters voted for it in 2011 and we just had more rains coming back and we held off until now. The drought conditions that we're having now are the worst we've had since I've been here," he said.