27 May 2009

Mexico Balances Competing Demands for Colorado River Water

Mexico uses water for agriculture, drinking water, wetlands

 

The Morelos Dam on the Colorado River is operated by Mexico under the supervision of the International Boundary and Water Commission.

The Morelos Dam on the Colorado River is operated by Mexico under the supervision of the International Boundary and Water Commission.

By Nancy L. Pontius
Special Correspondent

Littleton, Colorado — The Colorado River is a significant source of water for northern Mexico, Jesús Luévano, secretary of the Mexican Section of the International Boundary and Water Commission (IBWC), told America.gov.

About 80 percent of this water irrigates 200,000 hectares in the Mexicali Valley for growing corn, wheat, sorghum, cotton and vegetables. The remaining 20 percent is used for drinking water in the cities of Mexicali and Tijuana.

One other entity also competes for this water: the ecosystem of the river itself. Mexican and U.S. environmental groups are looking for water to restore and preserve the brackish wetland near the Colorado River delta of Sonora, Mexico, which includes the Cienega de Santa Clara in the Alto Golfo de California international biosphere reserve. “The IBWC is working with the environmental groups to find ways to share this water” for wetland preservation, Luévano said.

“We face the same problems as the U.S. — we need more water and right now the Colorado River is producing less water” than in the past, he said. “We are working together with the U.S. and the seven basin states to [determine] sustainable uses for the river.”

Also, “we’re working with the U.S. to use the water more efficiently,” Luévano said, such as by implementing more effective irrigation techniques and by lining the dirt irrigation canals to prevent water loss.

 

Mexican and U.S. environmental groups are looking for water to restore and preserve wetlands like this one in Mexico.

Mexican and U.S. environmental groups are looking for water to restore and preserve wetlands like this one in Mexico.

Investigations are under way to examine new ways to create useable water, such as by removing salt from seawater.

One issue of concern over the years is the level of salt in the Colorado River; this especially affects Mexico as the last user on the river system. “Peaks of salinity can be very dangerous and affect irrigated crops,” Luévano said. “Salinity levels increase when there is not enough water in the river system and we are now in one of those periods.”

 The United States has agreed to keep salinity levels at an acceptable level in the water it delivers to Mexico. “Mexico remains concerned about the salinity of deliveries, and the two countries have undertaken a number of initiatives to address these salinity concerns,” Sally Spener, a spokeswoman for the U.S. Section of the IBWC, told America.gov.

The United States has constructed a desalination plant in Yuma, Arizona, to reduce salt levels in the Colorado River, but this plant is not yet operational.

The Mexican Section of the IBWC oversees the country’s obligations to the basin, which includes operating Morelos Dam, the facility that diverts water from the United States into Mexico.  

“As agreed to in the Mexican Water Treaty of 1944, the U.S. delivers Colorado River water to Mexico on an annual basis, and Mexico delivers to the U.S. a minimum annual average of 350,000 acre-feet [432 million cubic meters] to the Rio Grande,” Spener said.

Mexico’s National Water Commission manages the Colorado River within Mexico, defining water-use policies and maintaining aqueducts and irrigation canals. Once inside Mexico, Colorado River water is Mexican federal property.

More information is available in Spanish at the Web site for the Mexican Section of the IBWC.