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B. Summary of Principal Options Considered w . U1 In the course of Mr. Brownell's investigation, a wide number of possibili- ,......, ~ ties were considered, ranging from projects of immediate practicability to W those whose feasibility has not been fully demonstrated. It was felt that some of these options could be employed individually or in combination with others and, indeed, Mr. Brownell's report recommended an approach to the negotiations with Mexico that would represent a combination of several techniques, It was also visualized that any new agreement that might be negotiated with Mexico would include, interalia, some undertaking by the United States to deliver Colorado River water to Mexico above Morelos Dam having a prescribed annual average of salinity greater than the salinity of the Colorado River waters which arrive at Imperial Dam. Hithin this frame. of reference, it would be the responsibility of the United States, by and large, to decide how it might fulfill any new obligations. The principal alternatives which were investigated are tabulated in Exhibit I and summarized as follows: 1. Desa lti ng PI ants Nine different cases were considered in which a desalting plant might be employed to contribute to a longterm decrease in the salinity of the waters delivered to Mexico. The principal distinguishing features of the various desalting options relate to the locations, size, and capacities of the plants considered, In most of these cases, desalting all or part of the drainage from the Hellton-Mohawk Irrigation and Drainage District was considered. This stems from the basic premise that the high saline content of the drainage from the Hellton-Mohawk Irrigation District was the occasion and the singular most important factor in the eyes of Mexico in raising the salinity of the waters reaching Mexico during the 1960's. However, for purpose of comparison, several more ambitious and more costly desalting schemes also were reviewed, includ- ing two postulated plants for desalting seawater that would be located near the Mexican and California coasts, respectively, as well as plants that would theoretically desalt the entire flows of the Colorado River, all of the drainage from the Palo Verde Irrigation District, or geother- mal brines for augmentation of the Colorado River. In general terms, all of the desalting plant options had the distinct advantage of conserving water resources and, as such, they held a special appeal for the Colorado River Basin states, given the scarcity of water in the general region. However, in. all cases, desalting plants presented the special problem of arranging for a suitable disposal of the brine that is produced as a necessary part of the operation. Accordingly, various forms of brine disposal were analyzed from an environmental as well as economic standpoint and, on balancing the options, it appeared that dis- posal with Mexican consent via a drain to the Santa Clara Slough would be the most attractive alternative. 4 .,"