No abstract

The United States is undergoing a dramatic growth of population and demands on its natural resources. The effects are widespread and often produce significant alterations of the environment. The hydrologic benchmark network was established to provide data on stream basins which are little affected by these changes. The network is made up of selected stream basins which are not expected to be significantly altered by man. Data obtained from these basins can be used to document natural changes in hydrologic characteristics with time, to provide a better understanding of the hydrologic structure of natural basins, and to provide a comparative base for studying the effects of man on the hydrologic environment. There are 57 benchmark basins in 37 States. These basins are in areas having a wide variety of climate and topography. The benchmark basins and the types of data collected in the basins are described. 1. BLACKWATER RIVER NEAR BRADLEY, ALA. (02369800) Location. About 50 miles inland from the Gulf of Mexico, south-central Alabama. Drainage area. 86.8 sq mi. Physiographic area. East Gulf Coastal Plain section of the Coastal Plain province of the Atlantic Plain. Climate. Average annual precipitation: about 61 in. Monthly mean temperature extremes: 52°and81°F. Topography. The uplands are gently rolling ridges which are somewhat broken in the central part of the basin. A few sinks and depressions are scattered in the eastern basin area. Basin elevations range from 125 to 300 ft. Rock type. Clay, sandy clay, sand, gravel, and sandstone. Vegetation. About 90 percent of the basin is covered by pine and hardwood forest. The remainder is in pasture and row crops. The upland forest is predominantly longleaf pine, and there is a dense wiregrass ground cover. The lowland forest is about 90 percent pine and 10 percent bay hardwood; the undergrowth is dense. Manmade influences. About 60 percent of the basin is publicly owned. Sections of this land are subject to being logged every 10 years. Extensive erosion control is practiced. The remaining 40 percent is 70 percent forest and 30 percent pasture and cultivation. Not more than 10 percent of the privately owned forests are normally cut in any one year. The land in row crops may produce unproportionately high sediment yields. Three small communities are within the basin. Gage location. Lat 31°01'45", long 86°42' 35", in SWi/4 sec. 24, T. 1 N., R. 25 W., 1.2 miles southeast of Bradley. Flow characteristics. Stream is perennial. Average annual runoff: about 23 in. Water quality. No information. Ground water. Water-table conditions prevail. Small to moderate quantities of water are yielded to domestic wells. Springs and seeps occur in the lower basin. Data collected. Type Period of record Low-flow streamflow measurements at 36 sites in the basin _ Various times. Continuous streamflow _____December 1967-present. Groundwater levels (intermittent observations in three wells) __________December 1968-present. Continuous precipitation ___December 1967-present. Type Period of record Cont...

A stream-quality reconnaissance at 318 locations in May 1965 offered the first opportunity for a contemporaneous regional collection and appraisal of water-quality data in Appalachia. The results provide a means of regional comparison of the influence of coalmine drainage on stream quality at approximately median streamflow. The results disclose that the chemical quality of the water at nearly 200 sites did not meet recommended drinking-water standards. At many of these sites, inferior quality was caused by excessive concentrations of solutes commonly associated with coalmine waters. Water-quality damage from mine drainage is particularly severe in the more heavily mined northern one-third of the region where high sulfate content, free mineral acidity, and low pH are typical of most affected streams. A deficiency in natural stream alkalinity in this part of the coal region contributes greatly to the massive effect of mine drainage upon stream quality. However, data collected from streams affected by mine drainage along the west edge of this part of the coal field suggest extensive neutralization of mine water. In southern Appalachia coalmine drainage had less influence on stream quality than in northern Appalachia. Fewer streams in this area were influenced by mine drainage, and the magnitude of stream damage for affected streams was less than in northern Appalachia. EXPLANATION Coal deposits Appalachia boundary as defined in Public Law 89-4 (1965) Figure 1. Location of coal deposits.

No abstract

No abstract