Publications

As the Nation's principal earth-science information agency, the U.S. Geological Survey (USGS) is depended upon to collect data of the highest quality. This document provides the framework for collecting, analyzing and reporting ground-water data that are quality assured and quality controlled.

Comal Springs of Central Texas are the largest springs in the southwestern United States. The long-term average flow of the Comal River, which essentially is the flow from Comal Springs, is 284 cubic feet per second (ft3/s). The artesian springs emerge at the base of an escarpment formed by the Comal Springs fault. The Comal River (fig. 1) is approximately 2 miles (mi) long and is a tributary of t

No abstract available

As part of the National Water-Use Information Program, the U.S. Geological Survey (USGS) stores water-use data in standardized format for different categories of water use. The data base (Site Specific Water Use Data System) is updated annually or as more current water-use information becomes available. Information about amounts of water withdrawn, sources of water, how the water was used, and how

To evaluate the effects of the 1993 flood in the upper Mississippi River Basin on the determination of flood magnitude and frequency, discharges that had recurrence intervals of 10, 25, 50, and 100 years computed from data through the 1992 water year were compared with those computed from data through the 1993 water year for 62 selected streamflow-gaging stations in Iowa. On the basis of the flood

Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Lower Minnesota River Basin, located in south-central Minnesota are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and we

Pipe-outlet terracing was effective in reducing sediment losses from a field site, but total nitrogen and phosphorus losses with runoff were not significantly different before and after terracing. Median concentrations of dissolved nitrate in several ground-water sampling locations increased after terrace installation. Dissolved nitrate concentrations in ground water decreased significantly after

The Regional Aquifer-System Analysis (RASA) Program of the U.S. Geological Survey was initiated in 1978 and was completed in 1995. The purpose of this program was to define the regional geohydrology and establish a framework of background information on geology, hydrology, and geochemistry of the Nation's important aquifer systems. This information is critically needed to develop an understanding

An understanding of the magnitude and frequency of low-flow discharges is an important part of protecting surface-water resources and planning for municipal and industrial economic expansion. Low-flow characteristics are summarized for 7 continuous-record gaging stations and 23 partial-record measuring sites in the Deep River Basin in North Carolina. Records of discharge collected through the 1995

Upper Klamath Lake and the connecting Agency Lake constitute a large, shallow lake in south-central Oregon that the historical record indicates has likely been eutrophic since its discovery by non-Native Americans. In recent decades, however, the lake has had annual occurrences of near-monoculture blooms of the blue-green alga Aphanizomenon flos-aquae that are thought to be a result of accelerated

Nitrate concentrations (as nitrogen) were analyzed in water from 73 wells completed in surficial aquifers. Water from about one-third of the wells had concentrations greater than 10 mg/L (milligrams per liter), the regulatory limit for drinking water established by the U.S. Environmental Protection Agency. Nitrate concentrations: (1) were greater in water from wells in agricultural settings than i

Confined glacial and bedrock aquifers are present within Quaternary and Cretaceous deposits that fill buried valleys incised in the Sioux Quartzite surface in Rock County, in southwestern Minnesota and Minnehaha County, South Dakota. This report describes the areal extent, thickness, water-bearing characteristics, water-supply potential, and water-quality characteristics of confined aquifers withi