Abstract

In eastern Curlew Valley, Utah, ground water flowing south-southwest in the Holbrook-Snowville flow system encounters a barrier near old Rose Ranch reservoir on Deep Creek. There, ground water may divert south-southeast toward northwest-dipping normal faults along the Hansel Mountains that project southwest toward Locomotive Springs. Total flow from Locomotive Springs averaged about 33 cubic feet per second (24,000 acre-feet per year) from 1969 to 1972, but declined by more than half between 1970 and 1980, and averaged about 14 cubic feet per second (10,100 acre-feet per year) from 1993 to 1996. This decrease likely results from cumulative withdrawals by new water wells, primarily near and northeast of the reservoir.

From Locomotive Springs northeast along the valley axis, the water level measured in wells drilled from 1968 to 1998, was 3 feet (1 meter) above to 20 feet (6 meters) below the level of the springs for 13 miles (21 kilometers), then rose more than 150 feet (45 meters) within 2 miles (3.2 kilometers) of the reservoir. Near the West Hansel fault system, the water level in 1993 was 81 feet (25 meters) below its recorded 1967 level. Withdrawals from sparse wells along the valley axis southwest of the reservoir are insufficient to cause much of the decline in discharge of Locomotive Springs.

Ionic compositions of water from two wells along the valley axis, in the zone where the hydraulic gradient is steepest, resemble those of carbonate-type water farther northeast in the Holbrook-Snowville flow system, but differ from those with high-chloride salinities southwest along the valley axis. A tongue of water with low concentrations of total dissolved solids extends southwest along the Hansel Mountains to Locomotive Springs, where peak discharges are in March and April. More rapid ground-water flow along a longer flow path is more likely along the West Hansel fault system than along the valley axis, where the Salt Lake Formation acts as a barrier to flow.