River Research & Design
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Large River & Physical Modeling Experience - David L. Derrick
Name: David Derrick
 Telephone: 601-638-7717
Cellular: 601-218-7717

For 19 years Mr. Derrick was the principle investigator on many physical movable-bed model studies involving some of the most hydraulically complex reaches of the Mississippi River. These research projects have involved the application of various river training structures to solve a number of environmental, navigation, and dredging problems.

He was instrumental in the development and implementation of the Bendway Weir methodology for navigable rivers, non-navigable rivers, streams, and very small streams.

A Bendway Weir is an upstream-angled underwater sill. Water flowing over the weir is redirected at an angle perpendicular to the weir. When the weirs are angled upstream water is directed away from the outer bank and toward the inner part of the bend. The river’s strong secondary currents in the bend are broken up. Weirs are typically built in sets (4 to 14 weirs per bend) and are designed to act as a system to capture, control, and redirect current directions and velocities through the bend and well into the downstream crossing.

Both model (since 1988) and prototype (1989) results indicate that construction of a series of Bendway Weirs in the navigation channel of a bend results in the following improvements: the navigation channel through the bend and immediate downstream crossing is widened and better aligned, deposition occurs at the toe of the revetment on the outside of the bend (increasing bank stability), surface water velocities are more uniform across any specific cross-section, flow patterns in the bends are generally parallel with the banks (not concentrated on the outer bank of the bend), and the thalweg of the channel is moved from the toe of the outer bank revetment to the stream ends of the weirs.

Using a physical movable-bed model, Mr. Derrick first explored and analyzed the multiple benefits of Bendway Weirs on two bends of the middle Mississippi River. Prototype Bendway Weir plans (and construction sequences) for these bends (Price’s Landing and Dogtooth) were developed using this model. Since 1989 over 190 weirs have been built in 22 bends of the Mississippi River. Prototype improvements have exceeded the results obtained from the model study. Andy Cannava of American Commercial Barge Line said “This is the best thing to happen on the river in a hundred years”. Analysis of the 5 oldest weir installations show that from 1990-95 dredging was reduced by 80%, saving $3,000,000. In addition, towboat accidents were reduced, tow delay times at bends were reduced, sediment and ice management were improved, Least Tern (an endangered species) nesting areas were undisturbed, aquatic habitat area was increased, and fish size and density in the weir fields dramatically increased.

This model study and associated prototype projects have revolutionized river training structure conceptualization and thinking to such an extent that St. Louis District present and future river plans almost exclusively involve Bendway Weirs. The weirs represent a unique and innovative solution to a perplexing set of problems in a number of bends where traditional solutions were not applicable.

Mr. Derrick has served as the principal investigator or designed all weir plans on the following Mississippi River physical movable-bed model studies that involved testing of Bendway Weirs: Greenville Bridge (improvement of current sets through a highway bridge navigation span), Memphis Harbor (shallow-draft navigation improvement), Old River (sediment diversion and navigation improvement), Redeye Crossing (deep-draft navigation improvement and protection of docking facilities) and St. Louis Harbor (improvement of navigation current sets through a series of six highway bridges). Mr. Derrick also tested weirs on the Montgomery Point reach of the White River (improvement of navigation approach channel to a lock and dam) and a small sand-bed stream model involving one unrevetted bend. In addition he assisted with the following movable-bed model studies: New Madrid, Old River (Fixed and Movable-bed), Kate Aubrey, Groins and Dikes Research, Lock and Dam 26, Redeye Crossing, Loosahatchie-Memphis Harbor, White River, and Buck Island.

Mr. Derrick designed a computer controlled automated sediment feeder to introduce coal into movable-bed models and assisted with the Redeye Crossing numerical and Greenville Bridge navigation modeling efforts.

Mr. Derrick conducted a four year Navigation Hydraulics research work unit, “Hydraulic Design of Bendway Weirs”, dedicated to expanding the envelope of knowledge of weir design in navigable rivers.

Mr. Derrick was the principle investigator in a four year REMR (Repair Evaluation, Maintenance and Rehabilitation) research work unit which inventoried all currently maintained Corps river training structures located in shallow-draft non-tidal influenced waterways (over 10,000 structures). This work documented all past dike repair work, recorded all current dike repair methods, evaluated all new technology related to the field of dike repair, and formulated guidelines for structure inspection, record keeping, evaluation, and repair. Results from this research unit were recorded in three REMR technical reports.

During 1997-2000 Mr. Derrick headed a team tasked with designing a 10 mile long innovative, cost-effective, bank stabilization project on a section of the laterally unrestrained Red River between Denison Dam and Index, AR (TX-OK border). Construction costs were estimated at 4-8 million dollars, less than one-half the cost of conventional bank protection. Mr. Derrick designed a 5-year monitoring program to assess the performance of this proposed project.