Rio Grande Water Quality Baseline Study for the Rio Grande, Canals, and Associated Drains from San Marcial, New Mexico to Fort Quitman, Texas

The purpose of this study was to provide a baseline for water quality in the drains, in wastewater return flows, and in the river of the waters of the Rio Grande Project in Texas and New Mexico. In recent years there have been rapid changes in the requirements for water quality that is returned to our nation’s rivers and streams. These changes to more restrictive standards have come about because of an increased national concern about the quality of water available for the multiple uses to which it is placed. This has led to a greater interest in water quality on the part of the management agencies of the Rio Grande Project.

The Rio Grande Project reaches from the headwaters of Elephant Butte Reservoir near San Marcial, New Mexico downstream to Ft. Quitman, Texas at the southern end of the irrigated lands. The Project is operated by the Bureau of Reclamation in cooperation with water districts in Texas and New Mexico.

This area, particularly the urban zone in the vicinity of EL Paso, Texas and Las Cruces, New Mexico is rapidly developing. Much of the formally irrigated lands is being subdivided into suburban residential housing, into smaller farm-residences, and some of the lands are being used for intensive agricultural and industrial operations. It can be expected that this characteristic of rapid development will continue for some time in the future. There are estimates that the irrigated valleys above and below Las Cruces and El Paso will be heavily populated by the year 2000, and that there will be eight hundred thousand people living on the American side of the Rio Grande in the Project area by that time.

Changes in water use will surely come with the associated land-use modifications. At the present time the majority of the Project water supply is still used for irrigation. Urbanization and industrialization will result in changes in water use, and it should also be anticipated there will be more intensive use of water for both agricultural and other purposes. More intensive use of water and changes in the point and purpose of use can have a marked effect on the quality of water available to downstream uses. The basic purpose of this study is to provide a sound foundation for the evaluation of future changes in quality.

Project No. 3109-312