A Comparison of a Standard Current Meter Sischarge Measurement Technique to One that Uses an Acoustic Doppler Current Profiler (ADCP) to Measure Discharge

Source: https://erdc-library.erdc.dren.mil/jspui/The Vicksburg District monitors multiple gaging stations along the Mississippi River using conventional methods. The records for these stations date back for many years giving the Corps an excellent understanding of bow the river discharge reacts to spring thaws and large-scale storm events. These records provide the Corps with information to maintain and operate the navigable waterways along the Mississippi. As technology develops, the Corps is always eager to incorporate new technology into its operating plans, but not without extensive testing. The Hydraulics Laboratory at the Waterways Experiment Station was contracted by the Vicksburg District to evaluate the present discharge measurement technique against a new technique using an Acoustic Doppler Current Profiler. A testing plan was developed to compare these two techniques over two different flow conditions. The focus of this report is to present the data from both exercises, describing how the two methods calculate discharge through a cross section and identifying possible sources of error

Near-Bed Optical Backscatter Sensor and Vector-Measuring Velocity Meter Calibration

Source: https://erdc-library.erdc.dren.mil/jspui/This report summarizes the procedures used to calibrate a Vector-Measuring Velocity Meter and an Optical Backscatter Turbidity Meter. Descriptions of facilities used in these calibration procedures are given, but they in no way limit the possibility of using other similar type facilities. Sensor thresholds and sensing limits are given to ensure accurate data collection

San Francisco Bay Long-Term Management Strategy (LTMS) for Dredging and Disposal. Report 2: Baywide Suspended Sediment Transport Modeling

Source: https://erdc-library.erdc.dren.mil/jspui/Field data analysis was used to examine suspended sediment transport in Central San Francisco Bay, and to develop and verify a two-dimensional numerical fine-grained sediment transport model. This study concerned the dispersion and fate of disposed dredged material in Central San Francisco Bay, California. The 1992 monitoring survey spanned a 2-week period in June, and used three boat-mounted acoustic Doppler current profiling (ADCP) systems to obtain repeated cross-sectional transects near the Golden Gate, the entrance to South Bay, and Richmond Point. Between acoustic transects, water samples were obtained over depth for salinity, total suspended material (TSM) concentration, and particle size determinations. Acoustic backscatter data were used to produce correlated suspended material concentration and flux fields. Discrete measurements were fit to empirical discharge and suspended flux models and integrated over a neap-spring-neap tidal sequence to estimate net transport. There was an observed net transport of suspended sediment seaward at the Golden Gate over the neap to spring sampling period. The total net transport was 188 x 10^6 kg (188,000 metric tonnes) seaward over 14 lunar days. Fluxes during the ebb flows averaged 44 percent greater than the flood flows, and instantaneous strong-ebb TSM fluxes were often more than twice those on flood tidal phases. Suspended sediment concentrations increased during the strongest part of the ebb at all Central Bay sampling_x000D_ ranges. Wind forcing did not appear important to this process. Suspended concentrations quickly returned to normal levels after the passage of peak ebb flows. Spatial variability in the TSM fields was relatively large. The ADCP backscatter intensity measurements correlated well with TSM especially on the Golden Gate range where a broadband unit was employed. The numerical sediment model reproduced the tidal flux across ranges adequately. Instantaneous TSM concentrations at a point were less well predicted by the model as was temporal variability. The model did not fully capture TSM variability. The model should be a useful tool in predicting general transport patterns in Central Bay

Effects of Breakwater Construction on Tedious

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