Upgrading water conveyance systems of south Texas

As much as 40 percent of the water gushing through the 4100 miles of canals and pipelines in the Rio Grande Valley is lost because of cracks, seepage, spills, and evaporation. That's a lot of water, especially for an area that has suffered from the drought and Mexico's nose-thumbing of the 1944 Water Treaty.

“They were state-of-the-art 100 years ago, but they're badly in need of repair today,” says Dr. Guy Fipps, irrigation expert at Texas Agriculture Experiment Station, College Station, of the water conveyance systems in South Texas.

The only way to save that water is to repair the infrastructure. And that costs plenty, hundreds of millions of dollars.

So, can we get the federal government to fund this?

There's good news on that front. Through the efforts of Texas lawmakers in Washington, $1.5 million has been allocated to start the project.

This may sound like being given an ounce when a ton is needed, but Dr. Ron Lacewell, TAES Associate Director at College Station, sees it differently. “It means we have traction now.”

The government knows the problem in South Texas and has begun to address the situation. “And we can thank the dedication of the Texas representatives and senators for this,” says Lacewell.

This initial allocation will fund a study of the infrastructure and for minor repairs. To people who feel that the situation has been studied enough and it is time for action, Lacewell counters, noting the cost per acre foot of water and per unit of energy saved must be established before more money is authorized. The project must be defined exactly to determine the money needed for the modernization of the conveyance systems. Estimates today run anywhere from $400 million to as high as $700 million.

This is a lot of money, but “we're talking about a lot of water,” Fipps explains. More than 300,000 acre feet of water could be saved per year. According to experts, including regional water planners, rehabilitating the system is the cheapest way to free up water — less expensive than building desalination plants or piping in water from other parts of Texas. Rehabilitation would include lining dirt canals or replacing them with pipelines, eliminating spills and building reservoirs and storage facilities within irrigation districts. Besides making repairs, new technology, such as using automatic gate controls, could be employed that would make for better management of the canal system.

A hundred years ago, when the first conveyance systems were established, inferior construction materials and methods were used and sealants were inefficient, allowing leaks to develop. Today we have far superior materials that can protect pipelines and canals from leaking.

“We will never have 100 percent efficiency in the system,” says Fipps, “but we can have 80 to 90 percent.”

A few of the irrigation districts have gone through some form of modernization. “Mostly the smaller districts, such as Brownsville, where they have installed underground pipelines in the last 15 years,” says Fipps. It's the larger irrigation districts that have the biggest problems, some still having open canals that are prone to leakage and evaporation.

In the Rio Grande Valley, the volume of water used is immense — about a million acre feet per year, or more than 325 billion gallons of water. The miles of canals and pipelines in the Valley — long enough to stretch from Key West to Seattle — are the lifeline to agriculture. And agricultural irrigation accounts for 90 percent of the water use in that area.

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