Potential hydrologic impacts of a tar-sand industry in 11 special tar sand areas in eastern Utah

About 93 percent of the Nation 's estimated 30 billion barrels of crude oil in tar sand deposits is in 11 tar-sand deposits in eastern Utah that were chosen for leasing by the Federal government. The Tar Sand Triangle area, which contains about 15 billion barrels of oil, is the largest. This area and the Sunnyside and P R Springs areas contain more than three-fourths of the Utah reserves. About 88,000 acre-feet of water per year would be required for a commercial tar-sand industry producing about 365,000 barrels per day. At this rate, most of the recoverable oil would be mined within 30 years. About 22,000 acre-feet of water per year would be required for a commercial tar-sand industry producing about 83,000 barrels per day. Impacts on local hydrology would be greatest in the Tar Sand Triangle, Sunnyside, and P R Springs areas. Impacts could be minimized with proper construction of surface facilities to decrease erosion, sediment transport, and impoundment of mining and retort water. Increases in salinity of the Colorado River at Imperial Dam, Ariz.-Calif., could be about 3 milligrams per liter, with a peak of 9 milligrams per liter, for a 365 ,000-barrel-per-day industry and less than 1 milligram per liter , with a peak of 2 milligrams per liter, for an 83 ,000-barrel-per-day industry. (USGS)