U.S. Geological Survey Bedload Sampling Policy
During the late 1960's, the U.S. Geological Survey's (USGS) Water Resources Division (WRD) developed the Helley-Smith bedload sampler. Since then, the USGS and the Technical Committee...
Incipient Motion in Gravel-Bed Rivers
Incipient motion processes are reviewed for bed material in gravel-bed rivers. Prediction difficulties are identified. Research results are reported for field and flume studies to investigate...
The Fallacy of Local Abutment Scour Equations
Existing laboratory model studies for quantifying local abutment scour deviate significantly from conditions typically found in the field. This has resulted in predictive local abutment...
Preliminary Studies of Pressure Flow Scour
Bridges that become inundated during floods have slightly pressurized flow that impacts bridge piers and creates an aggravated scour condition. Results of two preliminary laboratory studies...
Economics of Floods, Scour, and Bridge Failures
Hydraulic events occur more often and account for more losses than any other natural disaster. The damage inflicted on our nation's highway facilities during these events not only results...
Scour Around Bridge Piers in Oklahoma Streams in 1986
Historically, Oklahoma has received many severe rainfall and flooding events due to hurricanes hitting the coast of Florida and moving to the Gulf Coast area. One such event occurred during...
An Experimental Study of Bivalve Siphonal Jets in a Turbulent Boundary Layer Crossflow
We conducted experiments in a laboratory flume to study the interaction of bivalve siphonal jets with the turbulent boundary layer which forms in the benthic region of shallow estuaries....
Shape Effect on Bed-Load Transport in Pipes
The nature of part-full flows in pipe sewers produces different channel shapes resulting in non-uniform shear stress distribution on the wetted perimeter. New experimental data were utilized...
McCormick Bridge Scour Evaluation?A Case Study of a Tidal Bridge
Although the Federal Highway Authority has implemented procedures for bridge scour analysis in their HEC-18 publication, they do not indicate a procedure for scour depth determination...
A Tidal Inlet Bridge Scour Assessment Model
Undermining of bridge structures constructed in tidal inlets is a common problem. Scour mechanisms in tidal inlets are often complex combinations of local contraction and regional tidal...
Fish Screen Developments, Columbia River Dams
This paper describes developments to date for a fish diversion and bypass system being tested for two Columbia River dams. Because of the concern for the negative impacts of screen systems...
Flow Resistance Properties of Flexible Linings
Flow resistance for flexible channel linings is a function of the relative roughness of the lining in accordance with boundary-layer principles. As with vegetation, flexible linings have...
The Influence of Protective Material on Local Scour Dimensions
Protective materials installed around the base of a bridge pier can reduce or prevent local scour. The performance of four materials: grout mats, grout bags, footings, and riprap, are...
Repeatability and Oblique Flow Response Characteristics of Current Meters
Laboratory investigation into the precision and accuracy of various mechanical-current meters are presented. Horizontal-axis and vertical-axis meters that are used for the measurement...
Laboratory Study of the Characteristics of Shallow Open Channel Flow Using Fiber-optic Laser Doppler Velocimetry
An experimental study was proposed to investigate the characteristics of shallow rain-impacted flow using a recirculating flume and an artificial rainfall simulator. The fibre-optic Laser...
Distorted Physical Models for Mixing Studies
The frictional resistance and mixing process affected by roughness bars are investigated. Specific combinations of the size and layout of the bars for various flow conditions are suggested...
Determination of Pulsating Pressures for Baldhill Dam, N.D. Spillway
Model tests of the existing Baldhill Spillway were conducted with symmetrical and asymmetrical gate openings to determine for various flow conditions the characteristics of the hydraulic...
Hydraulic Model Studies of Y-Branch
Hydraulic model studies were made for the Y-branch steel penstock located in a vertical bend. The model tests were performed for various modes of pumping and generating operation. The...
Confirmation of Seismic Safety at Stafford Dam
A critical aspect of the North Marin Water District's mission to maintain reliable water supply facilities and water service is periodic assessment and re-evaluation of the seismic safety...
Pier Scour on the South Saskatchewan River
A continuing program to measure river bed scour near bridge piers and abutments on the Alberta rivers has been on going for over thirty years. The objectives are to verify the existing...
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