OCR Text |
Show PART IX PRESENT WATER USE Summary of Present Water Uses On-site depletions for 1965 related to man's activities were 3.45 million acre-feet. These depletions represent the average annual uses at the 1965 level of development. Data have been adjusted where necessary to reflect average conditions that may not have occurred in some areas during the year 1965. It should be specifically noted that these estimates of on-site depletions were made for the purposes of this framework study and are not to be construed as depletions charged to the various states under the provisions of the Colorado River and Upper Colorado compacts. In particular, they are site-located and do not necessarily reflect direct relationships to streamflow diminishment at Lee Ferry. By far, the largest depletion was by the 1.62 million acres of irrigated crops, associated seeped and incidental phreatophyte areas, and irrigation reservoir evaporation, which is 62 percent of the total or 2.13 million acre-feet. Minor water uses for other purposes were municipal and industrial (0.8 percent), minerals and power (1.6 per- cent), stockpond and livestock use (1.0 percent), and recreation and augmented fish and wildlife (.4 percent). Over one-half million acre- feet of water was being exported from the region by Colorado and Utah. Evaporation losses from main stem regulating reservoirs for 1965 conditions of normal operation were 643,000 acre-feet. For flexibility in analysis and planning, the region has been divided into three subregions comprising the natural drainage basins of the Green River, Upper Main Stem, and San Juan-Colorado. The Great Divide Closed Basin is included in the Green River Subregion. Summaries of stream depletions computed for the Upper Colorado Region by types of use for each subregion, and state follow. Respective companion appendices provide the sources and details of this data. 39 |