The streams in the Kentucky portion of the basin have low to moderate gradients. The Lower Cumberland drains 2,084 square miles in Kentucky and also a large portion of northern Tennessee. It also receives drainage from the Upper Cumberland River in Tennessee and southeastern Kentucky. In Kentucky, the Cumberland flows for 75 miles from the Tennessee border northwest to the Ohio River. Lake Barkley, created by the impoundment of the Lower Cumberland by Barkley Dam, extends 118 miles upstream into Tennessee. Approximately 44 miles of Lake Barkley lie within Kentucky. There are 696 miles of streams in the Kentucky portion of the basin. The two major subbasins in the region are the Little River (draining 601 square miles) and the Red River, which drains 1,456 square miles (only 687 of which are in Kentucky). Because of its remoteness from the rest of the study area, the Red River was not included in this project.
Major tributaries and embayments of Lake Barkley include, in addition to the Little River, Eddy Creek, Donaldson Creek, and Crooked Creek. Tributaries are distinguished from embayments by the larger flow into the reservoir from the tributaries. Most of the water in the embayments is a result of backflow from the reservoir. Major Lower Cumberland tributaries include Livingston Creek, Claylick Creek, Sandy Creek, and Sugar Creek.
Impacts:
In the past, agriculture has been the most prevalent nonpoint source of pollution in this basin. Cropland, pasture land, feedlots and animal holding/management areas are significant pollution sources. Cropland erosion has decreased dramatically in the region since 1988 because of the widespread adoption of conservation and no-till practices. Logging associated with silviculture (forestry) and streambank erosion have also contributed significant impacts. In the past, some mining impacts were reported in this basin from runoff from abandoned fluorspar mines (Livingston Co.) and limestone quarries. Sewage treatment plants and septic tanks contribute bacteria (pathogens) and nutrients. A limited number of industrial point sources are also located in the basin.
Periodically, portions of streams and reservoirs are sampled to determine if conditions in them support various uses, such as aquatic life, swimming, and domestic water supply. Suitability for drinking water use is determined mostly by data from drinking water facilities. A Kentucky Division of Water ambient monitoring station is located on the Little River near Cadiz. Data are collected monthly at these stations. biomonitoring station in the same location indicated only partial support for aquatic life in the 1992-1993 period. In the period from 1994 to 1995 water quality at this station has improved from nonsupport to full support of all uses. The Ohio River Valley Water Sanitation Commission (ORSANCO) operates a water quality sampling station located at mile 16 near Pinckneyville on the Lower Cumberland River.
During 1994 through 1995, streams in the Lower Cumberland River Basin (total of 696 stream miles) fully supported use as a drinking water source and fish consumption in all areas assessed (209.1 miles and 134.9 miles respectively). Swimming was not supported on 27.2 miles, but was fully supported on 101.7 miles. Conditions were favorable for aquatic life on 554.5 miles. Sixty-five miles partially supported aquatic life, and on 69 miles of the streams conditions were unfavorable for aquatic life.
An examination of the specific streams which are currently impaired shows that swimming is not supported in the lower portion of the Lower Cumberland (Livingston Co.) because of the presence of pathogens from septic tanks, municipal sewage treatment plants, sewer overflow, land disposal, and agriculture. The Little River (Trigg Co.) only partially supports aquatic life due to nutrients and siltation from agricultural practices. Pathogens, nutrients, and siltation from urban runoff and storm sewers, mining, and agriculture prevent swimming and only partially support aquatic life in the North Fork of the Little River (Christian Co.). During the period from 1994 to 1995, fourteen miles of the North Fork of the Little River did not support swimming due to the presence of pathogens from urban runoff, storm sewers, and agriculture. An industrial point source and nutrients and siltation from agriculture impaired the ability of the South Fork of the Little River (Christian Co.) to support aquatic life.
According to the 1996 Kentucky Report to Congress on Water Quality, Lake Barkley supports the following uses: warm water aquatic habitat, secondary contact recreation (boating and fishing), domestic water supply, and fish consumption. However, secondary contact recreation use is threatened by suspended solids from unspecified nonpoint sources. Bacteriological samples were not routinely taken; therefore, primary contact recreation (PCR) (swimming) was not assessed.
The U.S. Army Corps of Engineers conducted a study in 1986 of the water quality in Lake Barkley, its embayments and tributaries, and the Lower Cumberland below the dam. Certain parameters behave differently in large reservoirs than they do in streams due to greater depth and stratification. Also, it was found that conditions in the embayments were different from both the reservoir (Lake Barkley) and the tributaries. A summary of these data is available in Appendix I, Table B (on Lake Barkley and Lower Cumberland River) for use studying these differences and in comparing conditions in 1986 with those presently occurring.