Conference Papers

Since 1939, the date of the Project's inception, the team has operated under the direction of two lead agencies - the U.S. Geological Survey and U.S. Army Corps of Engineers. The supporting agencies are the Agricultural Research Service, Bureau of Reclamation, U.S. Forest Service, Bureau of Land Management, Federal Highway Administration, and the Tennessee Valley Authority. Overall...

Ten people died on April 5, 1987 as a result of the collapse of two spans of a New York State Thruway bridge into the floodwaters of Schoharie Creek. The cause of the bridge failure was determined to be scour of bed material from under the foundations of piers supporting the bridge. To evaluate the hydraulic conditions that produced the scour, a two-dimensional finite element surface...

The generalized viscoplastic fluid (GVF) model is used to derive the theoretical expressions of two-dimensional velocities and surface profile for debris flow established in a flume with bed driven by a conveyor belt. The rheological parameters of the GVF model are evaluated through the comparison of theoretical results with measured data. A slip velocity of the established (steady)...

A vertically integrated, two-dimensional hydrodynamic/transport model has been implemented for the upper extent of the Potomac Estuary between Indian Head and Morgantown, Md. The model computes water-surface elevations, flow velocities, and time-varying constituent concentrations by numerically integrating finite-difference forms of the equations of mass and momentum conservation in...

An investigation is being conducted to (1) quantify the short-term effects of freshwater agricultural drainage on salinity in a tidal creek and (2) evaluate the off-site effects of water-control structures on flow and water quality in channels that drain cropland in the Albemarle-Pamlico region of North Carolina. A continuous record of velocity is being obtained in three canals. Salinity...

Inflow and outflow to a dry-pond detention basin in Topeka, Kansas, were monitored for 19 storms during a 14-month period. Samples of runoff were collected automatically at two inflow and one outflow locations. Inflow and outflow constituent loads were computed with subsequent computation of load-detention efficiencies. Three constituents (dissolved solids, ammonia plus organic nitrogen...

Comparison of local scour depths at bridge abutments computed using different equations yields a large variation in predicted values. To consolidate the fragmented results of previous investigations and assemble the most comprehensive data set possible, reported laboratory measurements of local scour at the end of an obstruction protruding from the side of an open channel of rectangular...

Litter along Lousiana's beaches has become a well-recognized problem. In September 1987, Louisiana's first statewide beach cleanup attracted about 3300 volunteers who filled 16,000 bags with trash collected along 15 beaches. An estimated 800,173 items were gathered. Forty percent of the items were made of plastic and 11% were of polystyrene. Of all the litter collected, 37% was beverage...

In common with most branches of science, the management of riverine fish populations is characterised by reductionist and isolationist philosophies. Traditional fish management focuses on stocking and controls on fishing. This paper presents a consensus of scientists involved in the LARS workshop on the management of fish populations in large rivers. A move towards a more holistic...

This abstract refers to technical recommendations for avoiding, minimizing, and restoring (i.e., mitigating) drilling site access impacts related to oil and gas activities in coastal wetlands through regulatory review, drawing mostly from the Louisiana experience. The two standard methods used to access wetland drilling locations are canals and roads, both of which require dredging. Each...

Five tracer runs were performed on a detention pond and wetlands system to determine mixing and residence times in the system. The data indicate that at low discharges and with large amounts of storage, the pond is moderately mixed with residence times not much less than the theoretical maximum possible under complete mixing. At higher discharges and with less storage in the pond, short...

The City of Austin, Texas, has played a pioneering role in the control of urban nonpoint source pollution by enacting watershed and stormwater ordinances, overseeing detailed monitoring programs, and improving design criteria for stormwater control methods. The effectiveness of the methods used in Austin, and perhaps in other areas of the United States, to protect urban water resources...