Geology topics

A. W. Coen

Publications and source records attributed to A. W. Coen.

3 recordsLinked to original sources

USGS1992

Streamflow, water-quality, and biological data on streams in an area of longwall coal mining, southern Ohio, water years 1987-89

This report presents data on the first 3 years of a 5-year study of the effects of longwall coal mining on six streams near a mining complex in Meigs, Gallia, and Vinton Counties, Ohio. Longwall coal mining is method of underground mining in which 75 to 90 percent of the coal is removed; conventional methods, such as room-and-pillar mining, remove only about 50 percent of the coal. Use of the longwall method is expected to increase in Ohio. Collapse or subsidence of the overburden and land surface occurs immediately after the removal of the coal. Such collapse can disrupt surface drainage and the recharge of ground water. The data include streamflow, water quality, and the abundance and diversity of aquatic macroinvertebrates and fish. The data were collected from eight sites on six streams from July 1987 through September 1989. The drainage areas of these sites range from 2.04 to 80.8 square miles and include the major drainages of the area being mined. Total precipitation in 1987 and 1988 in the study area was 78 and 81 percent, respectively, of the annual average (from 1939 to 1989) of 39.59 inches. The total precipitation in 1989 was 135 percent of the annual average. Streams at six of the eight sites were dry for parts of the first 2 years. Specific conductance ranged from 180 to 3,500 microsiemens per centimeter at 25 degrees Celsius, pH ranged from 6.9 to 8.0, and the concentration of total recoverable iron ranged from 80 to 1,800 micrograms per liter. Macroinvertebrate and fish populations indicate a warmwater-habitat rating of fair to good according to Ohio Environmental Protection Agency standards. This information will help provide a data base from which the effects of longwall mining on streams in southern Ohio can be evaluated. Correlations of surface-water quality and quantity with longwall mining were not attempted in this study.

Open-File Report↗

USGS1990

Ground-water levels, flow, and specific conductance in unconsolidated aquifers near Lake Erie, Cleveland to Conneaut, Ohio, September 1984

This report described ground-water levels, flow, and specific conductance in aquifer along the southern shore of Lake Erie from Cleveland to Conneaut, Ohio. The data were collected in September 1984 as part of the U.S Geological Survey's Northeast Glacial Buried Valley Regional Aquifer-System Analysis. The study area is about 60 miles long, extends inland from the lake about 10 miles, and encompasses parts of Cuyahoga, Lake, and Ashtabula Counties. Water levels were measured in 202 existing wells, all of which were completed in the glacial deposits or at the contact with the underlying shale. Specific conductance was measured in 59 of the wells. Results of the survey are presented in table and map form. Unconsolidated material throughout the area consists primarily of till, whereas the bedrock consists of Devonian shale. The till is composed chiefly o silt and clay with some sand and gravel, and is less than 50 feet thick in most areas. Some valleys are filled with as much as 200 feet of glacial till and outwash deposits that are mainly sand and gravel. Ground-water levels in much of the area within 20 feet of the land surface. Contours of ground-water levels resemble a subdued version of those of the land surface, which indicates that ground water generally flows from high areas to low areas following the land-surface gradient. Locally, ground water discharges into streams. Regionally, flow is towards the north-northeast, to Lake Erie. Specific conductance ranged from 160 to 2,900 μ S/cm (microsiemens per centimeter at 25 degrees Celsius) with a median of 540 μ S/cm. Ground water with a specific conductance greater than 650 μ S/cm is localized, with no specific spatial pattern; possible sources of elevated specific conductance are road-deicing salt, leachate from landfills, natural brings associated with oil and gas drilling, and the leakage of saline water from bedrock.

Ohio↗

USGS1989

Ground-water resources of Williams County, Ohio, 1984-86

This report presents the results of a county-wide ground-water appraisal of Williams County, a mostly agricultural county of more than 36,000 people that is undergoing gradual commercial and industrial development. Most of the County's ground water is in the 80-to 320-foot thick cap of unconsolidated glacial sediments. The underlying Mississippian and older bedrock units are mostly Wisconsin till containing discontinuous lenses of sand and gravel. Two end moraines that cross the County form low northeast-southwest-trending ridges. Ground moraine covers the rest of the County except for fine sand and silt lacustrine sediments in the southeastern corner.The water-bearing sand and gravel bodies appear to be thickest and most widespread in the end moraines and thinnest and more localized in the lacustrine sediments. A generally productive (up to 1,000 gallons per minute) zone of sand and gravel and broken, weathered rock is present in places at the contact of the unconsolidated sediments and the shale. A study of well logs and aquifer tests shows that well yields of 500 gallons per minute are possible over all but the southeastern corner of the County. Transmissivities range from 2,800 to more than 64,300 feet squared per day. Storage coefficients that range from 0.0001 to 0.00038 indicate confined to semiconfined conditions. A gently southeast-sloping water-level surface was identified by measuring water levels in an 87-well network. A potentiometric-surface map constructed from these water-level measurements shows a fairly consistent gradient of 10 to 30 feet per mile across the County, which indicates that the unconsolidated sediments, on a large scale, act as one aquifer. Ground water flows toward the southeast. The recharge area for the ground-water system includes Williams County, and the area just to the northwest of Williams County, whereas the discharge areas are mainly the streams within and to the southeast of the County. Water quality in the unconsolidated sediments was evaluated through the analysis of samples from 48 wells. The predominately calcium magnesium bicarbonate type water generally is suitable for most uses, but is hard and high in iron. The median pH is 7.6, the median specific conductance is 600 microsiemens per centimeter, the median iron concentration is 1.4 milligrams per liter, and the median hardness (as CaCO3) is 290 milligrams per liter. Water in the southeastern corner of the County contains more sodium than elsewhere in the County. Seasonal variations in the ground-water quality are small. Analysis of four samples showed the water quality of area streams at base flow to be very similar, although slightly more dilute and less hard than the ground water.

Water-Resources Investigations Report↗