Publications

Statistical analyses were made of selected water-quality properties and constituents for Lake Travis, northwest of Austin in central Texas. Objectives for the evaluation were: (1) to provide information on levels of selected water-quality properties or constituents to use as reference values for assessing the future effectiveness of the Lake Travis Nonpoint-Source Control ordinance of the Lower Co

Simple and reliable methods for estimating hourly streamflow are needed for the calibration and verification of a Chattahoochee River basin model between Buford Dam and Franklin, Ga. The river basin model is being developed by Georgia Department of Natural Resources, Environmental Protection Division, as part of their Chattahoochee River Modeling Project. Concurrent streamflow data collected at 19

The depth distribution of temperature in lakes and reservoirs establishes vertical-density gradients that regulate the distribution of a wide array of chemical and biological features. In Lake Powell, the depth at which inflowing river water enters the reservoir is controlled by the water temperature of the river compared to the vertical-thermal structure of the reservoir in late spring and early

Data from more than 200 sites in nontidal portions of the Chesapeake Bay were compiled to document annual nutrient and sediment loads and trends for the period 1985 through 1996 as part of the 1997 Reevaluation of the Chesapeake Bay Program goal of reducing nutrient loads 40 percent by the year 2000. Annual loads were estimated by use of the Minimum Variance Unbiased Estimator (MVUE) model at

Elevated tritium concentrations in the unsaturated zone at the Amargosa Desert Research Site (ADRS), immediately south and west of the low-level radioactive-waste burial site south of Beatty, Nevada, have stimulated research of processes that control the transport of tritium in arid unsaturated zones. In May 1997, 58 samples were collected from 1.5 m (meters) depth within a 250 m by 250 m grid at

No abstract available.

Factors relating to the estimation of areas contributing recharge to wells, such as complexity of the ground-water flow system, effects of changing hydrologic conditions, and effects of well-screen locations and pumping rates, are reviewed. The point of view that simulation is the best means to obtain physically based estimates of contributing areas is emphasized. An extensive list of USGS reports

The city of Santa Barbara pumps most of its ground water from the Santa Barbara and Foothill ground-water basins. The Santa Barbara basin is subdivided into two storage units: Storage Unit I and Storage Unit III. The Foothill basin and Storage Unit I of the Santa Barbara basin have been studied extensively and ground-water flow models have been developed for them. In this report, the geohydrology

Ground-water discharge is a significant source of nitrate load to tidal creeks, coastal estuaries, and Chesapeake Bay. Different studies have found that forest buffers greater than 200 feet wide remove most of the nitrate from passing ground water. These buffers are commonly included in regional nutrient-management strategies. Results of a U.S. Geological Survey study on the Eastern Shore of Virgi

Methane gas, commonly referred to as "natural gas," is being produced from coal beds in central Utah (fig. 1) at an increasing rate since the early 1990s. The methane was generated over millions of years during the formation of coal in the area. Coal originates as plant matter that has been deposited in a swamp-like environment and then decays as it is buried and compressed over geologic time. Gia

The Susquehanna River contributes nearly 50 percent of the freshwater discharge to the Chesapeake Bay in a year of normal or average streamflow. The river also transports the greatest amount of nutrients (estimates of nearly 66 percent of the nitrogen and 40 percent of the phosphorus load) from all nontidal areas in the Chesapeake Bay Basin. Excessive nutrients in the Bay result in algal blooms th

Approximately 170 Mgal/d (million gallons per day) of ground- and surface-water was withdrawn from the Barataria-Terrebonne Basins in 1995. Of this amount, surface water accounted for 64 percent ( 110 MgaVd) of the total withdrawal rates in the basins. The largest surface-water withdrawal rates were from Bayou Lafourche ( 40 Mgal/d), Bayou Boeuf ( 14 MgaVd), and the Gulf Intracoastal Waterway (4.2