Lower Colorado River Multi-Species Conservation Program
The Lower Colorado River Multi-Species Conservation Program, or LCR MSCP, is a cooperative effort to address the needs of threatened and endangered species that may be affected by the operation and maintenance of the river from Lake Mead downstream to the Southern International Border. The Program has three goals:
▪ To conserve habitat and work toward the recovery of threatened and endangered species within the Lower Colorado River Basin, as well as reduce the likelihood of additional species listing under the Endangered Species Act.
▪ To accommodate current water diversions and power production and optimize opportunities for future water and power development consistent with the law,
▪ To provide a basis for incidental take permits under Section 10 of the Endangered Species Act.
To accomplish these goals a Program Steering Committee including federal agencies; water, power, and wildlife agencies from Arizona, California, and Nevada; irrigation districts and municipalities; power providers; conservation groups; and other affected interests developed a 50-year Habitat Conservation Plan (HCP). Official documents for the program were signed on April 4, 2005 during a ceremony at Hoover Dam. The HCP includes the creation of approximately 8,000 acres of new habitat, augmentation of fish populations, research and adaptive management.
Power and water supplies from the Colorado River benefit the entire state. Colorado River water is the largest renewable water supply in Arizona and hydroelectric power generated by the river is used in every county in Arizona. The LCR MSCP provides assurance that the benefits provided by the river to Colorado River communities, Central Arizona Project subcontractors, power users, recreational and environmental interests are not unnecessarily reduced in amount or increased in cost. The LCR MSCP provides a framework for Endangered Species Act compliance that supports the State’s continued economic growth and development.
Maintaining the quality of the Colorado River water supply is important. A number of contaminants, both naturally occurring and manmade, could impact the quality of Colorado River water including salinity, nutrients, metals, endocrine disrupting compounds, perchlorate, hexavalent chromium, bacteria, pathogens and sediment. Programs and planning efforts exist to monitor and address these water quality threats.
Increased salinity levels in the Colorado River affect agricultural, municipal and industrial users. Agricultural water users suffer economic damage due to reduced crop yields, added labor costs for irrigation management and chemical treatments and added drainage requirements. Urban users must replace plumbing and water-using appliances frequently. Industrial users and water and wastewater treatment facilities incur reductions in the useful life of system facilities and equipment. Damages in the United States are estimated at $330 million per year, and economic damage in Mexico, although not quantified, is a significant concern.
In 1972, EPA required development of water quality standards for salinity in the Colorado River in accordance with Clean Water Act (CWA) Section 303. The seven Colorado River basin states formed the Colorado River Basin Salinity Control Forum (the Forum) in 1973. The Forum developed numeric salinity standards for three locations in the lower Basin as well as a basin-wide plan of implementation. The EPA has approved the standards and the plan of implementation was adopted by the Colorado River basin states. The water quality standards establish a flow-weighted average annual salinity standard that must be maintained on the lower Colorado River at the following locations:
Below Hoover Dam (to Parker Dam) - 723 mg/L
Below Parker Dam (to Imperial Dam) - 747 mg/L
At Imperial Dam - 879 mg/L
Implementation of the salinity control plan has ensured compliance with the numeric criteria while the Basin states continue to develop the water allocated to them by the Colorado River Compact. For more information regarding salinity control, visit the United States Bureau of Reclamation and Colorado River Basin Salinity Control Forum websites.
The salinity of Colorado River water has also been a sometimes-contentious issue with regard to the water delivered to Mexico pursuant to the Mexican Water Treaty of 1944 (Treaty). The Treaty requires the United States to deliver 1.5 million acre-feet of Colorado River water each year to Mexico, absent Treaty surplus or shortage conditions. Salinity impacts to water users in Mexico became an issue after the Wellton-Mohawk Irrigation and Drainage District began discharging saline groundwater and return flows to the Colorado River above Morelos Dam, Mexico’s primary diversion point.
In 1961, Mexico lodged a formal protest with the United States claiming damages to agriculture in Mexico. The United States began a process to address Mexico’s concerns, which culminated in passage of the Colorado River Basin Salinity Control Act of June 24, 1974, Public Law 93-320 (the Salinity Control Act). The Salinity Control Act authorized a temporary measure to reduce the salinity of the Treaty water delivery by redirecting the brackish Wellton-Mohawk drainage water from the Colorado River to the Cienega de Santa Clara (Cienega) in Mexico. The Cienega now forms an important habitat for migratory birds and other animals. Each year approximately 109,000 acre-feet of water is delivered to the Cienega and is not counted as part of Mexico's Treaty allocation of 1.5 million acre-feet. The Salinity Control Act authorized the construction of the Yuma Desalting Plant, which was intended to capture and treat the drainage water flowing to the Cienega, and return most of it (71,000 to 85,000 acre-feet) to the River for delivery as part of the annual Treaty obligation.
The Yuma Desalting Plant was built and operated briefly, at one-third capacity in 1993, but that test run was cut short when flood flows on the Gila River damaged the intake canal. High flows in subsequent years reduced the salinity of the river sufficiently that the plant was not operated for several years. Ultimately, the plant was placed in "ready-reserve" status, when costs to repair the damaged intake canal and to operate the plant were considered too high to warrant its use. The plant was operated again at ten percent capacity for a 90-day test period in 2007. The impact of a prolonged drought in the Colorado River Basin has generated renewed interest in activating the Yuma Desalting Plant. Efforts are currently underway for a pilot run of the plant at one-third capacity to evaluate the potential for future operation.