withdrawn is not to be confused with consumptive use, because all of the withdrawn water is not consumed --much of it is returned to the stream system or groundwater basins for reuse. Table 27 presents the quantities of water withdrawn in 1965, by region, for the various uses--steam electric power generation, industrial, irrigation, livestock and domestic. Review of table 27 reveals that the total quantity of water withdrawn for those uses during 1965 in the 11 western states. was almost 114 million acre-feet. This compares with a total water yield of about 363 million acre-feet for the 11 western states. A comparison of water yields with water withdrawals in 1965, by Water Resource Regions, in millions of acre-feet, is presented in table 28. The consumptive use of water on public lands, that is the quantity of water actually evaporated and transpired, on the public lands under present conditions and as projected for the years 1980 and 2000 is presented hereafter. Present and Projected Future Consumptive Use of Water Water use by federal agencies for their various public land programs will directly affect the yield of water from such public lands. One of the primary purposes of this study was to inventory the water use by federal agencies under present (1967) conditions and the projected uses by those agencies in 1980 and 2000. Such uses are set forth in this section for public lands as heretofore defined and do not include uses on acquired federal lands. The method used in conducting this survey was by questionnaires directed to the various federal agencies by the Public Land Law Review Commission. The Forest Service was instrumental in establishing the form of the questionnaire, working in concert with the Commission staff and the resource contractor. Considerable time was required to comply, coordinate and process the data, and certain of the data were not available. However, from the data thus compiled, determinations, as hereafter set forth, were made of the consumptive use of water on the public lands. Such consumptive use of water on public lands is hereafter set forth as water requirements. The amounts of water currently used for public land uses from stream flow, storage facilities and subsurface sources Table 27.--Water Withdrawn by Water Resource Regions a7 Estimated use in applicable portions of Montana, Wyoming, Colorado and New Mexico. Source: U.S. Water Resources Council, The Nation's Water Table 28.--Comparison of Average Annual Yield with 1965 Water Withdrawals, by Water Resource Regions (Millions of acre-feet) presented in appendix J by agency. All data were provided by the reporting federal agency in the form as presented in appendix J. Livestock and Range Water Use. Livestock water use on the public lands and some related water spreading, principally for subirrigation of meadows, represented 83, 781 acre-feet of water consumptively used in 1967 according to agency responses. Only the Forest Service and Bureau of Land Management indicated appreciable amounts of water required by livestock on public lands. The projected future water requirements for federal agencies indicate that about 116, 200 acre-feet will be required in 1980 and about 152, 200 acre-feet will be required in the year 2000 for livestock grazed on public lands in the 11 western states. Table 29 presents the current and projected uses for such purposes for the various federal agencies. Big Game Water Use. The estimated quantities of water required by big game on public lands in 1967 were computed from average water consumption statistics per animal and the population of big game on the public lands. Currently, about 95 percent of the water required for big game on public lands is on lands of the Forest Service. This predominance of requirement on Forest Service lands is also reflected in the projected requirements for 1980 and the year 2000, Currently, the water requirement for big game on the public lands is about 22, 200 acre-feet, increasing to almost 25, 300 acrefeet by 1980 and to almost 26, 300 acre-feet by the year 2000. Table 30 presents the current and projected water requirements for big game on the public lands of the 11 western states for the various federal agencies. Recreational Activity Water Use. Water for recreational purposes includes use for domestic, culinary, waste disposal and for irrigation at recreation sites, camp grounds and picnic areas. Here again, the requirements of the Forest Service predominate over that of the other federal agencies. For 1967, the agencies reported recreational water requirements of 57, 351 acre-feet. The projected requirements for recreational activities in 1980 are estimated to be 57, 751 acre-feet and in the year 2000 are projected to reach 106, 948 acre-feet. The current and projected requirements for recreational activities on the public lands in the 11 western states for each of the various federal agencies are shown in table 31. Table 29.--Water Requirements for Livestock Grazed on Public a/ 24 404 517 427 83,781 116,624 152,204 Sheep grazing on Saylor CreekAAir Force Range water use was 10 quantified by Air Force. Source: Federal Agency responses to Public Land Law Review Commission. |