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the year 2015, but also determined the salt removal necessary when there is full development of the compact-apportioned waters of the Colorado River. In order to comply with the numeric criteria, the Forum has determined that at full development of the compact-apportioned waters, 1.8 million tons of salt annually must be removed or prevented from entering the system. The plan of implementation (described in Chapters 4 and 5) includes projects that have the potential for meeting the goal of removing the required tonnage. NUMERIC CRITERIA FOR S4LINITY Federal Re&UI~tion The federal regulation promulgated (see Appendix A) by the BPA required the adoption of numeric criteria by the states. The criteria are: Below Hoover Dam Below Parker Dam At Imperial Dam 723 mg/L 747 mg/L 879 mg/L The observed flow-weighted average annual salinity for the year 1972 was determined by Reclamation from daily flow and salinity data: collected by the U.S. Geological Survey and Reclamation. There is no inference that 1972 was chosen as the basis for establishing the numeric criteria because that year represented a typical or average year. Further, the plan of implementation is designed to offset the effects of human activity under long-term mean water supply conditions of 15 maf/yr. The Forum's basis for,selecting these stations is because of their proximity to key diversion facUities on the lower Colorado River. The State of Nevada diverts Colorado River main stem water from Lake Mead for use in the Las Vegas area, and its return flows move into the Lake and are part of the water supply available below Hoover Dam. The Metropolitan Water District of Southern California and the Central Arizona Project divert water from Lake Havasu, impounded behind Parker Dam, for many millions of users. The large agricultural areas in the Imperial and Coachel1a Valleys in California and the Yuma area in Arizona and California are served by diversions made at the Imperial Dam. All lower Basin water users s~ffer adverse impacts of high salinity to some degree. The criteria were not established to protect human health or fish and wildlife values. The salinity levels that are anticipated in the future, even without salinity control efforts, have not been shown to have adverse effects on human health or wildlife. Thus, this program is different than most other water quality standards programs. The Forum, responding to the requirements of Section 303(c) of the Clean Water Act, has conducted the review contained in this report. The Forum concludes that the numeric criteria need not be revised and sho~ld continue to be used. 3-2