Compacts, Decrees, and Treaties Affecting CO's Water

Home Browse Search

then releases greater than 8.23 maf will be made to maintain the active stotage in Mead and Powell at approximately equal amoums (equalization). The operaring criteria aLso pmvide for the release of water from Iake Mead to meet Mexican Treaty obligations, reasonable consumptive use requirements of mainstem users in the Lower Basin, net river losses, net reservoir losses and regulatory wastes. Until such time as these demands exceed 7.5 maf in the lower basin a normal water supply condition exists in the Lower Basin. Criteria for determining surplus and shortage conditions are aLso contained in the criteria. It has been demonstrated that the yield of the Colorado River System is less than what the 1922 compact negotiators originally believed. At Lee Ferry the yield only averages 15.0 millioa acre-feet annually. To the Upper Basin this means that its compact entitlement may be reduced by one-half the Mexican Treaty obligation or 750,000 acre-feet. While the Upper Basin states do not agree with this interpretation, the operating criteria still contain a minimum annual objective target release for Lake Powell of 8.23 million acre-feet aanually. When Reclamation further considers the yield to the Upper Basin during the critical period of record (drought period) the yield to the Upper Basin may only be 6.0 million acre-feet annually. A Upper Basin yield of only 6.0 million acre-feet means Colorado would only be entifled to consumptively use 3.079 million acre-feet annually. • Colorado River Basin Salinity Control Act (1974) Mexico had been complaining about the increasing salinity of Colorado River waters reaching its border. As a result, after years of negotiations and interim agreements, the nations signed Minute 242 of the International Boundary and Water Commission which. committed the IInited States to deliver water to-Mexico fmm xhe-. Colorado River containing no more than 115 parts per million of salt than the salt content of the water diverted to the All-American Canal at Imperial Dam (Imperial Valley). With this obligation, the CRBSCA was passed to initially fund four salinity control pmjects. The Act has subsequently been amended to include a number of other projects. State water right administration in Divisions 4, 5, 6, and 7 includes consideration of the limitations imposed by the "Law of the Colomdo River" in addition to the "appropriation doctrine. " As of 1985, Colomdo only beneficially consumed an average of 2.3 million acre-feet of Colorado River water annually, thus, limitations imposed by the Colorado River Compacts have not been a significant concem yet. However, as Colomdo approaches full utilization of its compact apportionment it will become more important to closely monitor Coloradds consumptive use of water on the west slope. The Colomdo River Decision Support 5