Environmental setting and its relations to water quality in the Kanawha River basin
The Kanawha River and its major tributary, the New River, drain 12,233 mi2 in West Virginia, Virginia, and North Carolina. Altitude ranges from about 550 ft to more than 4,700 ft. The Kanawha River Basin is mountainous, and includes parts of three physiographic provinces, the Blue Ridge (17 percent), Valley and Ridge (23 percent), and Appalachian Plateaus (60 percent). In the Appalachian Plateaus Province, little of the land is flat, and most of the flat land is in the flood plains and terraces of streams; this has caused most development in this part of the basin to be near streams. The Blue Ridge Province is composed of crystalline rocks, and the Valley and Ridge and Appalachian Plateaus Provinces contain both carbonate and clastic rocks. Annual precipitation ranges from about 36 in. to more than 60 in., and is orographically affected, both locally and regionally. Average annual air temperature ranges from about 43ºF to about 55ºF, and varies with altitude but not physiographic province. Precipitation is greatest in the summer and least in the winter, and has the least seasonal variation in the Blue Ridge Province. In 1990, the population of the basin was about 870,000, of whom about 25 percent lived in the Charleston, W. Va. metropolitan area. About 75 million tons of coal were mined in the Kanawha River Basin in 1998. This figure represents about 45 percent of the coal mined in West Virginia, and about seven percent of the coal mined in the United States. Dominant forest types in the basin are Northern Hardwood, Oak-Pine, and Mixed Mesophytic. Agricultural land use is more common in the Valley and Ridge and Blue Ridge Provinces than in the Appalachian Plateaus Province. Cattle are the principal agricultural products of the basin. Streams in the Blue Ridge Province and Allegheny Highlands have the most runoff in the basin, and streams in the Valley and Ridge Province and the southwestern Appalachian Plateaus have the least runoff. Streamflow is greatest in the spring and least in the autumn. About 61 percent of the basin's population use surface water from public supply for their domestic needs; about 30 percent use self-supplied ground water, and about nine percent use ground water from public supply. In 1995, total withdrawal of water in the basin was about 1,130 Mgal/d. Total consumptive use was about 118 Mgal/d. Surface water in the Blue Ridge Province is usually dilute (less than 100 mg/L dissolved solids) and well aerated. Dissolved- solids concentrations in streams of the Valley and Ridge Province at low flow are typically greater (150-180 mg/L) than those in the Blue Ridge Province. The Appalachian Plateaus Province contains streams with the most dilute (less than 30 mg/L dissolved solids) and least dilute (more than 500 mg/L dissolved solids) water in the basin. Coal mining has degraded more miles of streams in the basin than any other land use. Streams that receive coal-mine drainage may be affected by sedimentation, and typically contain high concentrations of sulfate, iron, and manganese. Other major water-quality issues include inadequate domestic sewage treatment, present and historic disposal of industrial wastes, and logging, which results in the addition of sediment, nutrients, and other constituents to the water. One hundred eighteen fish species are reported from the Kanawha River system downstream from Kanawha Falls. Of these, 15 are listed as possible, probable, or known introductions. None of these fish species is endemic to the Kanawha River Basin. The New River system has only 46 native fishes, the lowest ratio of native fishes to drainage area of any river system in the eastern United States, and the second-highest proportion of endemic fish species (eight of 46) of any river system in the eastern United States.