Appraisal Report Central Arizona Project

Document: "Appraisal Report Central Arizona Project-Chapter III", January 1962, page 36Through this hydrologic coordination, comprehensive water conservation would be achieved by the combination of water salvage through channel improvement, storage control, and watershed soil and moisture programs. For maximum project benefit, direct use of the import water as a base flow would be necessary, requiring seasonal variation in ground-water pumping and storage reservoir draft. Within the Maricopa area, the regimen change from agricultural to urban uses will alter the hydrologic cycle. Flows which formerly reached the ground-water reservoir by deep percolation of applied water will, in the future, become increasingly available at treatment plant outfalls. The magnitude of these import and local supply return flows may approach 650,000 acre-feet annually under full project conditions. Flows from this source would be of a quality adequate for agricultural purposes, and would probably be of sufficient magnitude to supply agricultural lands within economical transport distance. This water, utilized as a surface supply, would leach through the soil and carry excessive dissolved solids through and below the root zone. Drainage of the lands upstream from the barrier at Gillespie Dam would require a system of open drains and drainage wells. The magnitude of future drainage water discharge over Gillespie Dam has not been evaluated in this report. Canalside water delivery quantities shown in table 5 indicate the potential project water service to water needs of the Central Service Zone. These quantities are used for establishing facility design requirements and for economic analyses. Subsequent modifications may be expected after later determinations are made on distribution to various areas of need. 36Epson Perfection 4870 Photo, 400 dpi, 8 bit, 1,042,516 byte