Geology topics

Tom Brooks

Publications and source records attributed to Tom Brooks.

3 recordsLinked to original sources

USGS1985

Reconnaissance of ground-water resources in the lower Gunnison River basin, southwestern Colorado

Information about ground-water quantity and quality in the lower Gunnison River basin assists in developing, appropriating, and managing the basin 's water resources. Hydrogeologic data are presented for 51 wells and 61 springs. Chemical analyses are given for 34 wells and 17 springs. Drillers ' reports for 71 wells are included. Springs normally discharge from short alluvial flow systems and commonly are less saline than well water. These springs are a calcium magnesium bicarbonate water type. Spring discharges of as much as 200 gallons per minute were measured. The most productive wells in the study area are completed in alluvium, with reported yields of as much as 750 gallons per minute for an irrigation well. Alluvial gravels are most productive. Specific-conductance values of water samples from alluvial deposits ranged from 80 to 32,200 micromhos per centimeter at 25 Celsius. The Mancos Shale and Mesaverde Formation include aquifers with large areal extents. Reported yields of wells completed in the Mesaverde Formation range from 0.7 to 24 gallons per minute. The Dakota Sandstone, Morrison Formation, and Entrada Sandstone include potential aquifers of lesser extent. Reported yields of wells completed in the Dakota Sandstone range 5 to 14 gallons per minute in the study area. Specific-conductance values of water samples from the Mesaverde Formation ranged from 325 to 5,390 micromhos per centimeter at 25 Celsius. Insufficient data prevented water-quality analysis of other rock units. (USGS)

Water-Resources Investigations Report↗

USGS1985

Hydrology of coal-lease areas near Durango, Colorado

The U.S. Bureau of Land Management leases Federal lands and minerals for coal mining near Durango, Colorado. This report addresses the hydrologic suitability of those lands for coal leasing; the report describes the general hydrology of the Durango area and, more specifically, the hydrology of the Stollsteimer Creek study area 32 miles east of the Durango and the Hay Gulch study area, 12 miles southwest of Durango. The most productive aquifers in the Durango study area are Quaternary alluvium and the tertiary Animas Formation. Water wells completed in alluvium typically yield 5 to 20 gallons/min; wells completed is the Animas Formation yield as much as 50 gallons/min. Water quality in these aquifers is variable, but it generally is suitable for domestic use. The coal-bearing Cretaceous Fruitland and Menefee Formations are mined by surface methods at the Chimney Rock Mine in the Stollsteimer Creek study area and by underground methods at the National King Coal Mine in the Hay Gulch study area. Effects of surface mining in the Stollsteimer Creek area are: (1) Dewatering of an alluvial aquifer; and (2) Local degradation of alluvium water quality by spoil-pile effluent. Effects of underground mining in the Hay Gulch area are: (1) Introduction of water with greater dissolved-solids concentrations into the upper Hay Gulch alluvium from mine runoff; (2) Subsidence fracturing which could dewater streams and the alluvial aquifer. (USGS)

Water-Resources Investigations Report↗

USGS1983

Hydrology and subsidence potential of proposed coal-lease tracts in Delta County, Colorado

Potential subsidence from underground coal mining and associated hydrologic impacts were investigated at two coal-lease tracts in Delta County, Colorado. Alteration of existing flow systems could affect water users in the surrounding area. The Mesaverde Formation transmits little ground water because of the neglibile transmissivity of the 1,300 feet of fine-grained sandstone, coal , and shale comprising the formation. The transmissivities of coal beds within the lower Mesaverde Formation ranged from 1.5 to 16.7 feet squared per day, and the transmissivity of the upper Mesaverde Formation, based on a single test, was 0.33 foot squared per day. Transmissivities of the alluvium ranged from 108 to 230 feet squared per day. The transmissivity of unconsolidated Quaternary deposits, determined from an aquifer test, was about 1,900 feet squared per day. Mining beneath Stevens Gulch and East Roatcap Creek could produce surface expressions of subsidence. Subsidence fractures could partly drain alluvial valley aquifers or streamflow in these mines. (USGS)

Water-Resources Investigations Report↗