Geology topics

David S. Mueller

Publications and source records attributed to David S. Mueller.

25 records · Page 2Linked to original sources

USGS1994

Design and operation of a system to monitor sediment deposition for protection of an endangered mussel

The USGS, in cooperation with the COE, has designed and installed a system to continuously monitor changes in elevation of the river bed over the mussel bed located downstream of the Olmsted Locks and Dam project. The installed system utilizes a multi-transducer acoustic ranging system to provide river bed elevation measurements accurate to plus or minus 1 cm. The system is currently collecting data to assess the baseline sediment deposition and erosion characteristics of the mussel bed.

Conference Paper↗

USGS1994

Real-time data collection of scour at bridges

The record flood on the Mississippi River during the summer of 1993 provided a rare opportunity to collect data on scour of the streambed at bridges and to test data collection equipment under extreme hydraulic conditions. Detailed bathymetric and hydraulic information were collected at two bridges crossing the Mississippi River during the rising limb, near the peak, and during the recession of the flood. Bathymetric data were collected using a digital echo sounder. Three-dimensional velocities were collected using Broadband Acoustic Doppler Current Profilers (BB-ADCP) operating at 300 kilohertz (kHz), 600 kHz, and 1,200 kHz. Positioning of the data collected was measured using a range-azimuth tracking system and two global positioning systems (GPS). Although differential GPS was able to provide accurate positions and tracking information during approach- and exit-reach data collection, it was unable to maintain lock on a sufficient number of satellites when the survey vessel was under the bridge or near the piers. The range-azimuth tracking system was used to collect position and tracking information for detailed data collection near the bridge piers. These detailed data indicated local scour ranging from 3 to 8 meters and will permit a field-based evaluation of the ability of various numerical models to compute the hydraulics, depth, geometry, and time-dependent development of local scour.

Conference Paper↗

USGS1993

Evaluation of historical scour at selected stream crossings in Indian

Geophysical data were collected by means of ground-penetrating radar and tuned transducer systems to estimate the historical scour at ten bridges in Indiana. These geophysical data were used to compare and evaluate the results of 13 published pier-scour equations. In order to make this comparison, it was assumed that the measured historical scour was associated with the peak historical discharge. Because the geophysical data were not sufficient to map the lateral extent of the refilled scour hole, local scour could not be isolated from concentration scour. For the evaluation, computed contraction scour and pier scour were used in combination with the existing channel geometry to determine a computed bed elevation. This computed bed elevation was compared to be minimum historic bed elevation estimated from the geophysical data. None of the selected pier-scour equations, when combined with the contraction-scour equation, accurately represented the historical scour at all of the study sites. On the basis of the limited data presented, the equations currently recommended by the Federal Highway Administration provided a combination of accuracy and safety, required by design equations, equal to or better than the other equations evaluated.

Conference Paper↗

USGS1993

Reference surfaces for bridge scour depths

Depth of scour is measured as the vertical distance between scoured channel geometry and a measurement reference surface. A scour depth measurement can have a wide range depending on the method used to establish the reference surface. A consistent method to establish reference surfaces for bridge scour measurements is needed to facilitate transferability of scour data an scour analyses. This paper describes and evaluates techniques for establishing reference surfaces from which local and contraction scour are measured.

Conference Paper↗

USGS1993

Instrumentation for detailed bridge-scour measurements

A portable instrumentation system is being developed to obtain channel bathymetry during floods for detailed bridge-scour measurements. Portable scour measuring systems have four components: sounding instrument, horizontal positioning instrument, deployment mechanisms, and data storage device. The sounding instrument will be a digital fathometer. Horizontal position will be measured using a range-azimuth based hydrographic survey system. The deployment mechanism designed for this system is a remote-controlled boat using a small waterplane area, twin-hull design. An on-board computer and radio will monitor the vessel instrumentation, record measured data, and telemeter data to shore.

Conference Paper↗

USGS1993

Bridge-scour analysis using the water surface profile (WSPRO) model

A program was developed to extract hydraulic information required for bridge-scour computations, from the Water-Surface Profile computation model (WSPRO). The program is written in compiled BASIC and is menu driven. Using only ground points, the program can compute average ground elevation, cross-sectional area below a specified datum, or create a Drawing Exchange Format (DXF) fie of cross section. Using both ground points ad hydraulic information form the equal-conveyance tubes computed by WSPRO, the program can compute hydraulic parameters at a user-specified station or in a user-specified subsection of the cross section. The program can identify the maximum velocity in a cross section and the velocity and depth at a user-specified station. The program also can identify the maximum velocity in the cross section and the average velocity, average depth, average ground elevation, width perpendicular to the flow, cross-sectional area of flow, and discharge in a subsection of the cross section. This program does not include any help or suggestions as to what data should be extracted; therefore, the used must understand the scour equations and associated variables to the able to extract the proper information from the WSPRO output.

Conference Paper↗

USGS1993

Development of bridge-scour instrumentation for inspection and maintenance personnel

Inspecting bridges and monitoring scour during high flow can improve public transportation safety by providing early identification of scour and stream stability problems at bridges. Most bridge-inspection data are collected during low flow, when scour holes may have refilled. More than 25 percent of the States that responded to a questionnaire identified lack of adequate methodology and/or equipment as reasons for not collecting scour data during high-flow conditions. Therefore, the U.S. Geological Survey (USGS), in cooperation with the Federal Highway Administration, has begun to develop instrumentation for measuring scour that could be used by inspection and maintenance personnel during high-flow conditions. A variety of instruments and techniques for measuring scour were tested and evaluated in real-time bridge-scour data-collection studies by the USGS. In the National Scour study, fathometers were found to be superior to sounding weights and will be the primary bed-measuring instrument. The ability of low-cost fathometers and fish finders to locate the bed accurately is being evaluated. Simple and efficient methods for deploying the transducer during floods are also important for a successful measurement. The information and additional testing are being used to design new, portable scour-measuring systems.

Conference Paper↗