The International Boundary and Water Commission, United States and Mexico (IBWC), has reached agreement to convey water to the Santa Clara Wetland in Mexico in conjunction with the Pilot Run of the Yuma Desalting Plant (YDP) in the United States. The agreement was formalized in IBWC Minute No. 316, which was signed in Yuma, Arizona on April 16, 2010 by U.S. Commissioner Edward Drusina and Mexican Commissioner Roberto Salmon; the Minute was subsequently approved by the governments of both countries.

The YDP Pilot Run being undertaken by the U.S. Bureau of Reclamation began May 3, 2010 and will cover 365 operating days within an 18-month period, producing 29,000 acre-feet (35.8 mcm) of usable water. The YDP was constructed by the United States government to comply with agreements regulating the salinity of Colorado River water allotted to Mexico under the 1944 Water Treaty. It operated briefly in late 1992 and early 1993 but since then the United States has used other means to reduce the salinity of water deliveries, including bypassing saline irrigation return flows to the Wellton-Mohawk Bypass Drain, which eventually flows to the Santa Clara Wetland in the State of Sonora. During the YDP Pilot Run, a portion of these irrigation return flows will be desalinated and included in Colorado River deliveries to Mexico.

Absent other actions, operation of the YDP would reduce the quantity and increase the salinity of water flowing through the Wellton-Mohawk Bypass Drain to the Santa Clara Wetland. Given the interest of both governments in preserving the environmental values of the Santa Clara Wetland during the YDP Pilot Run, Minute No. 316 establishes a commitment by Mexico, the United States and non- governmental organizations of both countries to contribute 10,000 acre-feet (12.3 mcm) of water each to the Santa Clara Wetland. Additionally, Minute No. 316 provides that Mexico and the non-governmental organizations from both countries may temporarily use the Wellton-Mohawk Drain and the U.S. conveyance system to deliver water to the Santa Clara Wetland in connection with the YDP Pilot Run. This water contributed by the two governments and the non-governmental organizations helps to preserve the ecosystem of the Santa Clara Wetland, part of the Colorado River Delta Biosphere Reserve in Mexico.

The agreement also includes a binational environmental monitoring program of the Santa Clara Wetland, which includes participation by institutions from both countries and $250,000 in funding from the Metropolitan Water District of Southern California (MWD), Southern Nevada Water Authority (SNWA), and Central Arizona Water Conservation District (CAWCD), the non-federal agencies partnering with the United States on the YDP Pilot Run. The United States has also agreed to provide additional funding and equipment to assist with the maintenance of the Wellton-Mohawk Drain in Mexico.

“This agreement addresses water supply, water quality, and the environment,” said U.S. Commissioner Edward Drusina. “This is another success in the Commission’s efforts to increase U.S.-Mexico cooperation in the Colorado River Basin.”

Mexican Commissioner Roberto F. Salmon highlighted the importance of this agreement and stated that it will allow the Yuma Desalting Plant to operate while keeping said operation from having environmental impacts on the Santa Clara Wetland, a highly environmentally-sensitive area that is of utmost importance to Mexico.

Minute No. 316 is based on a Joint Report of the Principal Engineers of the Commission signed in July 2009. The agreement was developed with the participation and cooperation of the U.S. Bureau of Reclamation, Environmental Defense Fund, MWD, SNWA, CAWCD, Mexico’s National Water Commission (CONAGUA), Mexico’s Ministry of the Environment and Natural Resources (SEMARNAT) and Pronatura Noroeste.

Contact:
Sally Spener, 915-832-4175, sally.spener@ibwc.gov