Geology topics
Research about central Utah
Source-linked reports with geographic coverage including central Utah.
Hydrologic monitoring in the coal fields of central Utah, August 1978-September 1979
Surface-water quantity and quality were observed at 12 gaging stations downstream from mined and lease areas in the Wasatch Plateau, Book Cliff's, and Emery coal fields in central Utah. Measurements of base flow were made at 52 additional sites in the region. The report describes the hydrologic setting of this important coal region and summarizes the surface-water data collected at the monitoring sites from August 1978 through September 1979. Coal mining and lease activities in each of the monitored basins also are described. Where possible, hydrologic impacts of coal mining are evaluated. Impacts include increases in streamflow and degradation of surface-water quality due to water discharged from underground mines. Other impacts include removal of water from ground-water storage, changes in the natural ground-water flow system, and possibly the diminution of spring flows. Adequacy of the monitoring network to detect hydrologic changes due to mining is evaluated. In order to fully assess and quantify the impacts, comprehensive studies and monitoring of the ground-water system and water produced in mines are needed.
Hydrology of the coal-resource areas in the upper drainages of Huntington and Cottonwood creeks, central Utah
The hydrology of coal-resource areas in the upper drainages of Huntington and Cottonwood Creeks in central Utah was studied in order to better define the hydrologic system, to identify the hydrologic effects of underground coal mining, and to devise methods to detect the effects. Discharge records from gaging stations in this mountainous area indicated that there are large differences in the annual discharge of streams per unit area of drainage. These differences are attributed to differences in precipitation, differences in evaporation and sublimation of the snowpack, and to subsurface movement of water out of some basins. Surface waters sampled during 1977-79 were of good chemical quality; dissolved-solids concentrations rarely exceeded 500 milligrams per liter. The Star Point Sandstone and the lower coal-bearing part of the Blackhawk Formation, both of Cretaceous age, are saturated in some areas, and the aquifer yields water to underground coal mines. Most of the larger discharging springs in the study area issue from the Star Point-Blackhawk aquifer where faulted. Ground water also occurs in several water-bearing zones above the Star Point-Blackhawk aquifer. It is not known whether the water in these overlying units is part of a continuous zone of saturation or whether unsaturated zones occur between units and some water is perched. Dissolved-solids concentrations in water from about 140 springs ranged from 50 to 750 milligrams per liter. The chemical characteristics of water from the water-bearing zones of different formations usually were very similar. Dewatering of underground coal mines was the largest manmade discharge from the Star Point-Blackhawk aquifer in the study area during 1979. The dewatering of mines has decreased the amount of water in storage in the aquifer, but water-level data were not available to define the extent of the depletion. Other possible impacts due to mine dewatering include the diminution of spring flows and increases in ground-water recharge, both of which are more likely to occur where rocks have been fractured due to subsidence above mines. Also, the flows of streams that receive water discharged from mines probably have increased accordingly. The discharge of mine water into streams causes some degradation in surface-water quality, but the quality of ground water is probably not adversely affected by mining. Some environmental changes associated with underground mining are difficult to detect without data collected over a long period. With respect to the ground-water system, the year-to-year similarity of spring-discharge recession curves may provide a method to detect some of these changes. Changes in the benthic-invertebrate population may help detect pollution of surface waters. Comprehensive studies of the ground-water system are needed in conjunction with hydrologic monitoring in order to fully assess the hydrologic impacts of the underground coal mining.