Effects of coal mining on the water resources of the Tradewater River Basin, Kentucky

Abstract

The effects of coal-mine drainage on the water resources of the Tradewater River basin, in the Western Coal Field region of Kentucky, were evaluated (1) by synthesis and interpretation of 16 years of daily conductance data, 465 chemical analyses covering an 18-year period, 28 years of daily discharge data, and 14 years of daily suspended-sediment data from the Tradewater River at Olney and (2) by collection, synthesis, and interpretation of chemical and physical water-quality data and water-quantity data collected over a 2-year period from mined and nonmined sites in the basin. Maximum observed values of 13 chemical and physical water-quality parameters were three to 300 times greater in the discharge from mined subbasins than in the discharge from nonmined subbasins. Potassium, chloride, and nitrate concentrations were not significantly different between mined and nonmined areas. Mean sulfate loads carried by the Tradewater River at Olney were about 75 percent greater for the period 1955-67 than for the period 1952-54. Suspendedsediment loads at Olney for the November-April storm-runoff periods generally vary in response to strip-mine coal production in the basin above Olney. Streamflow is maintained during extended dry periods in mined subbasins after streams in nonmined subbasins have ceased flowing. Some possible methods of reducing the effects of mine drainage on the streams are considered in view of a geochemical model proposed by Ivan Barnes and F. E. Clarke. Use of low-flow-augmenting reservoirs and crushed limestone in streambeds in nonmined areas seems to be the most promising method for alleviating effects of mine drainage at the present time. Other aspects of the water resources such as variability of water quantity and water quality in the basin are discussed briefly. INTRODUCTION Coal mining has affected the streams in the Tradewater River basin in western Kentucky since the late 1800's. Oxidation of iron sulfide minerals in abandoned underground mines causes the formation of 2 EFFECTS OF COAL MINING, TRADEWATER RIVER BASIN sulfuric acid; discharge of this mine water into streams leads to changes in water quality. By the 1940's, surface mining of coal had become an important industry in the area. The disturbance of earth materials during surface coal-mining operations exposes iron sulfide compounds which increase dissolved solids in streams. In addition, the exposed materials become more easily eroded and sediment loads of streams are increased. The acidic conditions (low pH) along with increased dissolved solids and sediment loads have led to the destruction of fish and other aquatic life and have rendered the affected water undesirable for public, industrial, or domestic supplies. Coal-mining activities have also created such objectionable sights as spoil banks, treekills in bottom lands, red-tinted water in streams and ponds, and stream channels covered with red iron hydroxide. This study was made to determine the effects of coal mining on the water resources of the Tradewater River basin. The study provides background data for future more intensive investigations and research regarding the causes and contro.1 of mine drainage in the basin. The U.S. Geological Survey conducted this study as a part of the cooperative water-resources-investigation program with the Kentucky Geological Survey. A special note of acknowledgment is due J. E. Palmer and others in the Madisonville office of the U.S. Geological Survey, the Kentucky Geological Survey, and Tennessee Valley Authority for help with the geology of the area; P. H. Murdoek of the Kentucky Water Pollution Control Commission, and R. J. Pickering of the U.S. Geological Survey for help in the early stages of waterdata collection; and Douglas Griffin of the Division of Water, Kentucky Department of Natural Resources, for assistance in data synthesis and analysis. The cooperation of landowners and companies as exemplified by Ames Oil and Gas Company and Island Creek Coal Company is appreciated. BASIN CHARACTERISTICS The Tradewater River basin is in western Kentucky (fig. 1) and the river is the only major tributary to the Ohio River between the Cumberland River on the west and the Green River on the east. It occupies 943 square miles along the southwestern edge of the Western Coal Field in six Kentucky counties Caldwell, Christian, Crittenden, Hopkins, Union, and Webster. The basin is approximately 52 miles long and is 32 miles wide between the towns of Marion on the west and Madisonville on the east. TOPOGRAPHY AND STREAMS