WSP12246 - Laserfiche WebLink

Home Browse Search

,.-," C 1'\, (.,)v.' Stage 11, which began in 1986, involved lining about 40 mi of canals and replacing about 320 mi of laterals with underground pipeline. When Stage II is com- pleted, the estimated decrease in salt load to the Colorado River would be ] 51 ,000 tons/yr (Bureau of Reclamation, 1985a, 1986). By early 1994, about two-thirds of Stage II was completed. The USDA on-farm salinity-control program was started in 1979 in the Grand Valley and has contin- ued through 1994. Once completed, the estimated decrease in dissolved-solids loading attributed to the on-farm improvements would be 132,000 tonslyr for the Grand Valley Unit (Hedlund, 1994). Approxi- mately 50 percent of the USDA salinity program in the Grand Valley was completed by early 1994 (Emory Johnson, Natural Resources Conservation Service, oral commun., ]994). Lower Gunnison Basin Unit The Lower Gunnison Basin Unit consists of the Gunnsion River Basin downstream from Blue Mesa Reservoir, including the North Fork Basin (fig. I). The primary irrigation project in this area is the Uncompahgre Project (fig. I), which supplies water for irrigation of about 86,000 acres. The BOR salinity program in the Lower Gunnison Basin Unit was focused only on the Uncompahgre Project. The BOR (1982,1984) estimated that about 360,000 tonslyr of salt came from irrigation-induced sources in the Uncompahgre Project. The estimated annual dissolved-solids loading from the entire Lower Gunnison Basin Unit was about 640,000 tons (Bureau of Reclamation, 1984). The BOR's Winter Water Replacement Program was designed to replace the practice of using winter flows in canals and laterals for livestock watering by expanding the existing rural domestic water systems in the Uncompahgre Project (Bureau of Reclamation, ] 987). The replacement pro- gram was estimated to decrease the annual dissolved- solids loading from this area by 74,000 tons. Construc- tion of the Winter Water Replacement Program began in 1990 and, by late 1994, was about 95 percent com- pleted (D.W. Crabtree, Bureau of Reclamation, oral commun., 1994). Another salinity-control feature planned for the Lower Gunnison Basin Unit is the East Side Lateral Program, which is planned to replace about 188 mi of laterals and 7 mi of small canals on the east side of the Uncompahgre Project with underground pipe- line (Bureau of Reclamation, 1994). That program would decrease dissolved-solids loading from the Uncompahgre Project by about 64,000 tons/yr. The East Side Lateral Program was scheduled to begin in 1995, but presently (1995) has been deferred (U.S. Department of the Interior, 1995). The total irrigated area in the Lower Gunnison Basin Unit that was studied by the USDA for their salinity-control work is 171,000 acres, which includes the Uncompahgre Project. Once completed, the USDA on-farm improvements were estimated to decrease dissolved-solids loading from the Lower Gunnison Basin Unit by about 166,000 tonslyr (Hedlund, 1994). The USDA on-farm improvements were initiated in 1988 in the Lower Gunnison Basin Unit. Meeker Dome Unit Meeker Dome is a local uplift located east of Meeker in the White River Basin (fig. 2). The White River is a tributary of the Green River, which is tri butary to the Colorado River. The Meeker Dome Unit was a BOR project that consisted of plugging three abandoned oil wells drilled in Meeker Dome. The wells provided conduits for the vertical move- ment of saline, deep ground water into shallow aqui fers, which then discharged into the White River (CH2M Hill, ] 979, 1982). The purpose of the well plugging was to decrease discharge of the saline ground water into the White River. One well was plugged in December 1980; the other two wells were plugged by June 1981. A post-project study by CH2M Hill (1982) reported significant decreases in chloride loading with measurable decreases in dissolved-solids loading from Meeker Dome. Also, seeps and springs dried up, and water levels in observa- tion wells decreased after the wells were plugged. Detailed monitoring activities ended in 1984 and, in a concluding study, the BOR (l985b) estimated that about 19,000 tonslyr of salt was removed from the White River by the Meeker Dome Unit well plugging. The saline ground water had high chloride and sodium concentrations; the BOR (I 985b) reported marked decreases in concentrations of those constituents in the river after the well plugging. 6 Trend Analysis 0' Selected Water-Ouality Data Associated With SBllnlty-Control Projects In the Grand Valley. In the Lower GunnIson River Basin, and at Meeker Dome. Western Colorado