On behalf of the National Park Service, the U.S. Geological Survey during the summer of 1959 made a study of ground-water conditions in the area of the Grant Village site, along the shore of the West Thumb of Yellowstone Lake, 1 to 2 miles south of the present facilities at West Thumb. The water supply for the present development at West Thumb is obtained from Duck Lake, but the quantity of water available from this source probably will be inadequate for the planned development at Grant Village.
During the investigation, 11 auger holes were bored and 6 test wells were drilled. Aquifer tests by pumping and bailing methods were made at two of the test wells. All material penetrated in the auger holes and test wells is of Quaternary age except the welded tuff of possible Pliocene age that was penetrated in the lower part of test well 4.
Small to moderate quantities of water were obtained from the test wells in the area. Test well 2 yielded 35 gpm (gallons per minute) at a temperature of nearly 100 deg F. Test well 6 yielded about 15 gpm at a temperature of 48 deg F. The yield of this well might be increased by perforation of additional sections of casing, followed by further development of the well. Water from the other four test wells was of inadequate quantity, too highly mineralized, or too warm to be effectively utilized.
Most of the ground water sampled had high concentrations of silica and iron, and part of the water was excessively high in fluoride content. Otherwise, the ground water was of generally suitable quality for most uses.
The most favorable area for obtaining water supplies from wells is near the lakeshore, where a large part of the water pumped would be ground-water flow diverted from its normal discharge into the lake. Moderate quantities of relatively cool water of fairly good quality may be available near the lakeshore between test wells 5 and 6 and immediately east of test well 6.
