Making the most of a limited resource
EL PASO Mild winters, low humidity, lots of room, cultural diversity, higher education opportunities and a lively economy El Paso has a lot to offer.
But one thing it doesn't have is a lot of water.
Enter Texas Agricultural Experiment Station researchers, who study ways to make the most of the area's limited water supply.
El Paso sprawls at the base of the Franklin Mountains in the farthest point of West Texas. The terrain is mostly desert except for the Rio Grande, which meanders along the southern edge of the city, marking the Texas-Mexico border.
The river also marks the most valuable source of agricultural water in the area, said Dr. Zhuping Sheng, Experiment Station hydrogeologist in El Paso.
Sheng and his research assistant, geologist Joshua Villalobos, are involved in ongoing research to determine more efficient ways of utilizing water from the Rio Grande for agriculture, while protecting residents' water needs and the environment. Researchers from New Mexico State University in Las Cruces are also participating in the study.
"It's a delicate balance between irrigation needs, municipal needs and environmental needs," Sheng said.
The land in the Rio Grande valley near El Paso is the richest farmland in the area, Villalobos explained. And to help keep it that way, beginning more than 100 years ago a series of canals was built to help deliver the water to the fields.
One of the oldest of these canals the Franklin Canal was constructed in the late 19th century, he said.
Currently the El Paso Country Improvement District No. 1 operates and maintains about 350 miles of canals and laterals to divert water from the river for agricultural applications and municipal and industrial uses, Sheng said.
Most of the canals and the irrigation ditches that feed from them are basically ditches dug in the natural soils of the area, which means some of the water is lost through seepage, Villalobos said.
Several month ago, the El Paso County Water Improvement District No. 1 put down about 800 feet of thin rubber lining on a portion of the Franklin Canal to determine its effectiveness in canal lining, Sheng said.
In fact, research by Sheng and Dr. Phillip King from the department of civil engineering at NMSU has shown that 10 percent to 30 percent of the water delivered by the system of canals is lost through seepage.
Sheng and Villalobos are studying how lining certain areas of the canals might impact the interaction between ground water and surface water.
"We want to know how it will affect the soil moisture content," Villalobos said, "since much of the water is absorbed in the soil." The different soil types in the canals affect seepage rates, Villalobos said. In some areas the clay soil forms a natural barrier and keeps seepage rates lower.
"Other areas with sandy bottoms lose water easily," he said.
Using data collected from tests and measurements of the Franklin and other canals and laterals, the researchers have made some preliminary findings. They believe that lining 10 miles of canals could potentially save enough water for 1,000 acres of crops or 8,000 homes.
They also found that lining canals is expensive; therefore determining where water loss is greatest and lining those areas would be the most cost-effective.
Preliminary results will soon be published by Texas Water Resources Institute and New Mexico Water Resources Research Institute. Even so, said Sheng, the research will be continued to confirm the potential water savings by canal lining.
Additional monitoring will be implemented to assure the performance of canal lining and high delivery efficiency, he added.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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