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Chapter V . .' Ability of Title I to Support Program Objectives " This chapter discusses the ability of Title I to support its primary objective of providing Mexico with Colorado River water that meets negotiated salinity standards without depriving the Basin States of any of their apportioned water, It also discusses the ability of Title I to advance desalting technologies. Supporting the Primary Objective Before Completion of the YDP The United States has complied with the salinity differential since 1974. That is, the average annual salinity of the water delivered to Mexico at the Northerly International Boundary, upstream from Morelos Dam, has not exceeded the average annual salinity of the water arriving at Imperial Dam by more than 115 ppm plus or minus 30 ppm (maximum of 145 ppm), Figure 3 shows the annual flow-weighted salinity at Imperial Dam from 1973 through 1991. Figure 4. shows the annual salinity differential for the same period (the salinity at the Northerly International Boundary less the salinity at Imperial Dam). The United States has complied with the salinity differential through the temporary measures of bypassing all WMIDD irrigation drainage to the Santa Clara Slough, substituting good quality water from upstream storage for treaty deliveries to Menco, and, for an interim period that began in 1982, claiming as replacement 1 the water conserved by lining the Coachella Canal, AB stated previously, under Public Law 93-320, the replacement of irrigation drainage bypassed to meet the salinity differential is recognized as a national obligation, The United States has secured interim use of 132,000 acre-feet per year of replacement water by lining the Coachella Canal, However, the United States has not secured water to replace the amount bypassed in excess of 132,000 acre-feet per year, which totaled 5,900, 6,000, and 13,000 acre-feet in calendar years 1989, 1990, and 1991, respectively. Over the past 10 years, the amount of irrigation drainage bypassed has ranged from a high of 192,000 to a low of 118,500 acre-feet per year. Supporting the Primary Objective in the Future With the YDP Under present conditions, the YDP, if operated at full capacity, would be able to recover more than half of the WMIDD irrigation drainage. Until the interim period ends, the water conserved by the lining the Coachella Canal will be sufficient to replace the reject stream and anycbypassed WMIDD irrigation drainage required for essential operations, even if the YDP is operated at one-third capacity (22.4-MGD production), 1 EXC8pt at such time. when there existed IIUlplus water for the Colorado River under the term. of the 1944 water treaty with Mexico. 27