Publications

A method for estimating the height reached by floods having recurrence intervals of 10, 20, and 100 years is defined for unregulated streams in Charlotte and Mecklenburg County draining areas of less than 1.0 square mile. Flood heights, defined as the vertical distance between the streambed at riffles and the floodwater surface, can be used to estimate flood elevations on small streams where flood

The 3,550 square miles of the Upper Chattahoochee River basin is an area of diverse physiographic and land-use characteristics. The headwater areas are mountainous with steep, relatively narrow channels. Land in the headwater areas is heavily forested, but small towns and farms are common in the valleys of large streams. Downstream, the basin is characterized by low hills and wider stream channels

Extensive modification and excavation of stream channels in the 6-square mile Chicod Creek basin began in mid-1979 to reduce flooding and improve stream runoff conditions. The effects of channel improvements on this Coastal Pain basin 's hydrology will be determined from data collected prior to, during, and for several years following channel alternations. This report summarizes the findings of da

Land-surface subsidence has been mapped in the Houston-Galveston area and is known to have occurred in other areas within the Texas coastal region. Most of the subsidence has been caused by both the withdrawal of ground water and by the production of oil, gas, and associated ground water. Land-surface subsidence was determined by comparing adjusted elevations of bench marks for various periods of

Hydrologic investigations of urban drainage basins in Texas were begun by the U.S. Geological Survey in 1954. These studies are now in progress in Austin, Dallas, Dallas County, Fort Worth, Houston, and San Antonio.The Geological Survey, in cooperation with the Texas Department of Water Resources, expanded the existing gaging-station network in the San Antonio metropolitan area in May 1968 to begi

Water-level measurements in wells were started by the USGS in Iowa in 1935. Since then a total of about 450 different wells have been measured. The present network consists of about 70 wells. The measurement of these water levels aids in evaluating the present and future water resources of the State. Many factors influence water-level fluctuations. These factors include atmospheric pressure, withd

This map shows the altitude of the water table in the alluvial and Wilcox aquifers in the vicinity of Richland and Tehuacana Creeks and the Trinity River, Tex., in December 1979. The water-table contours were constructed on the basis of water-level control derived from an inventory of shallow wells in the area, topographic maps, and field locations of numerous small springs and seeps. (USGS)

A three-phase study was conducted during July and August 1979 to determine the effects of varying release rates through the power-outlet works at Sam Rayburn Reservoir, eastern Texas, on aeration capacity of a 14-mile reach of the Angelina River below Sam Rayburn Dam. The dominant factors that affected the aeration capacity during the study time were time of travel and the dissolved-oxygen deficit

A technique for estimating the magnitude and frequency of floods in the Houston, Texas, metropolitan area was developed by use of a multiple-regression flood-frequency analysis of flow data from unregulated streams in the area. A regression model, relating flood-peak discharge to concurrent rainfall and antecedent soil moisture conditions, was used to simulate 67-year records of annual peak discha

A water-quality study of the Neuse River, N.C., based on data collected during 1956-77 at the U.S. Geological Survey stations at Clayton and Kinston, employs statistical trend analysis techniques that provide a framework for river quality assessment. Overall, water-quality of the Neuse River is satisfactory for most uses. At Clayton, fecal coliform bacteria and nutrient levels are high, but algae

The Ogallala aquifer of Texas historically has been known for elevated fluoride concentration, with many areas in excess of 4 milligrams per liter. In addition, on a regional scale, silica concentrations are also somewhat elevated, with concentrations averaging in the 40 to 50 milligrams per liter range. This aquifer provides a unique geochemical and epidemiological study area because it is comple

This report continues a publication format that annually presents both water-level and water-quality data. In this format the information is presented in two-page units: the left page presents a text which summarizes the information for an area or subject and the right page consists of one or more illustrations. Daily mean water-level fluctuations and trends are shown in hydrographs for the previo