POWRE: Development of Instrumentation for In-Situ Measurement of Bottom Shear Stress over Moveable Beds at LEO-15 The proposed effort involves the development of a multi-directional shear plate to obtain in-situ direct bottom shear stress measurements over moveable beds at the Long-term Ecosystem Observatory (LEO-15) research area located offshore of the southern coast of New Jersey in 15 m of water. These types of measurements are of critical importance to ocean scientists and engineers. Numerical models for sediment transport, for the prediction of wave transformation in shallow water, and for the circulation of water bodies on meso- and large- scales, all require as input estimates of bed shear stress. At the present time, the direct measurement of the time-average bed shear stress, EMBED Equation.2 , under complex flow regimes remains unattainable; estimates of EMBED Equation.2 used for sediment transport and wave transformation models are obtained through indirect methods. A technique for the direct measurement of the bottom shear stress over a moveable bed in the laboratory was recently developed by the Principal Investigator (Rankin, 1997). This technique offers direct, real time measurements of the bottom shear stress and does not require information about the flow characteristics in the boundary layer above the bed; it is thus well suited for complicated flow regimes. I propose to continue the development of a shear plate device for use at LEO-15. The proposed instrumentation development effort will contribute in several significant ways to our knowledge of sediment transport and oceanographic field installation, and to the nation's academic research infrastructure. The development of this device will be of value to physical oceanographers modeling sediment transport and hydrodynamic processes, to environmental engineers studying dredging techniques and mapping the fate and transport of contaminated sediments and to biological oceanographers examining the patch dynamics of benthic communities. The POWRE award would have a significant impact on the career of Dr. Rankin. As a new investigator, this award will provide an opportunity to enhance her research activities through the development of new instrumentation and access to state-of-the-art oceanographic field equipment. Through POWRE's Visiting Professor program, Dr. Rankin will be afforded the opportunity to collaborate with a nationally known team of oceanographers.
