|
<br />Land Use
<br />
<br />Land designated for use as rangeland or forest in
<br />the study unit comprises the largest land use, account-
<br />ing for about 85 percent of the study unil(fig, 8), Live-
<br />stock (sheep and cattle) use large areas of rangeland for
<br />foraging, Forest land that includes most of the moun-
<br />tain and plateau areas is used for some commercial
<br />lumber production from lodgepole pine, Englemann
<br />spruce, and Douglas fir, Forest land also provides wild-
<br />life habitat and recreational opportunities,
<br />Large parts of the study unit are set aside for
<br />recreational use, including all or parts of 4 National
<br />Park Service areas, II Forest Service wilderness areas,
<br />\ \ State parks, numerous State Wildlife Management
<br />area~, and 17 ski area~, Toorism and recreational activ-
<br />ities are a major industry in the study unit.
<br />Mining is another important land use in the study
<br />unit. Past and present mining activities have included
<br />the extraction of metals (copper, gold, lead, molybde-
<br />num, nickel, silver, vanadium, and zinc) and energy
<br />fuels (coal, gas, oil, oil shale, and uranium),
<br />Urban land is one of the smaller land uses in the
<br />mostly rural Upper Colorado River Basin, A number
<br />of urban areas are associated with development activi-
<br />ties resulting from the expansion of the ski industry
<br />and, in the 1980's, fromenergy-developmentactivities,
<br />Historically, urban land use was a~sociated with
<br />agricultural activities,
<br />Agriculture is the traditional land use in the study
<br />unit in counties such as Delta, Garfield, Gunnison,
<br />Mesa, and Montrosc, Agricultural activities include
<br />production of crops such as alfalfa, fruits, grains, hay.
<br />and vegetables, Little crop production is possible with-
<br />out irrigation because of the semiarid climate, Irrigated
<br />lands are predominantly in river valleys or low-altitude
<br />regions where the water is supplied by an extensive
<br />system of canals and ditches,
<br />
<br />Water Management
<br />
<br />Water management in the study unit is greatly
<br />affected by the 1922 Colorado River Compact and the
<br />1948 Upper Colorado River Basin Compact. The 1922
<br />Colorado River Compact divided the Colorado River
<br />Basin into upper and lower basins at Lee Ferry, Ariz"
<br />and apportioned the beneficial consumptive use, The
<br />1,948 Upper Colorado River Basin Compact appor-
<br />tioned the water of the upper basin to five States
<br />(Arizona, Colorado, New Mexico, Utah, and Wyo-
<br />ming) having drainage areas that contribute to the flow
<br />of tlJe Colorado River, An annual total of7,5 million
<br />acre, feet of water was apportioned to the upper basin,
<br />
<br />allocating 50,000 acre-ft annually to Arizona, The
<br />remaining water is allocated to the upper ba~in as
<br />follows: Colorado, 51.75 percent; New Mexico,
<br />11.25 percent; Utah, 23 percent; and Wyoming,
<br />14 percent (U,S, Department of the Interior, 1993),
<br />In the Colorado River Basin, management of
<br />water quality has been greatly affccted by three public
<br />laws: the Federal Water Pollution Control Act
<br />Amendments of 1972 (Public Law 92-500), required
<br />the eSlablishment of a criterion for dissolved-solids
<br />concentrations; the Colorado River Basin Salinity Act
<br />(Public Law 93-320), established in 1974, authorized
<br />construction of 4 salinity-control projects and develop-
<br />ment of an additional 12 projects; and the 1984 amend-
<br />ment to Public Law 93-320 (PL98-589) gave authority
<br />to the Bureau of Reclamation and the U,S, Department
<br />of Agriculture to install salinity controls needed to
<br />meet the criteria for dissolved-solids concentrations,
<br />In the study unit, there are 9 major interbasin
<br />water transfers exceeding 4,500 acre-ftlyr. 7 major
<br />water divelOions, 9 major reservoirs, and 10 major
<br />municipal discharges for major cities in the basin,
<br />These structures are shown in figure 9 and listed in
<br />table 3, For water year 1993, the nine major interbasin
<br />water transfers conveyed about 585,000 acre-ft of
<br />water from the Upper Colorado River Ba~in to the
<br />South Platte. Rio Grande. and Arkansas River Basins,
<br />These interbasin water transfelO provide supplemen-
<br />tary irrigation and municipal water supplies to the
<br />receiving South Platte, Arkansas, and Rio Grande
<br />drainages, About 25 percent of the interbasin water
<br />transfers is for the municipal water supply for the
<br />Denver metropolitan area,
<br />
<br />Water Use
<br />
<br />Most of the water used in the study unit comes
<br />from surface-water sources; nevertheless, ground
<br />water is an important resource in remote and rural area~
<br />where the water predominantly is used for domestic
<br />purposes, Estimated offstream water use from surface
<br />water in the study unit during 1990 totaled about
<br />3,500 MgaVd as listed in table 4, Ground-water
<br />sources accounted for less than I percent of the water
<br />used, The principal water use in the basin is for irriga-
<br />tion, which accounts for about 97 percent of the off-
<br />stream water use (table 4), The remaining 3 percent is
<br />accounted for by the following in order of decreasing
<br />water use: livestock, domestic, power, industria/, com-
<br />mercial, and mining,
<br />Conswnptive use, which includes water that has
<br />evaporated, transpired, been incorporated into crops
<br />or products, or consumed by humans or livestock,
<br />
<br />14 Environmental Selling end Implications on Walo, Quellly, Upper Colorado River Baaln, Colorado end Utah
<br />
|