SALINITY INTRUSION Chesapeake/Delaware Bays Deepening Study - CHT assisted the US Army Engineer Research and Development Center (ERDC) at Vicksburg, MS on this study. The purpose of the study was to assess the impact on salinity intrusion and circulation of deepening the navigation channels in the Delaware Bay, the C&D Canal, and the upper Chesapeake Bay from their existing authorized depths. The three-dimensional CH3DZ model was applied with and without channel deepening using boundary forcings from 1993 and 1965. The 1993 forcings contained several typical events such as large setups and set downs in the water surface, along with a large flood event. The hydrology of 1965 contained the drought of record for the region. SEDIMENTATION Atchafalaya Bay Bar Channel Study - CHT is conducting this study for the New Orleans District of the US Army Corps of Engineers. The purpose of the study is to predict the impact of deepening the Atchafalaya Bay bar channel on the formation and transport of fluid mud within the channel. In addition, the impact of various structural alternatives will be investigated. A sediment transport fluid mud model has been developed in the three-dimensional CH3DZ hydrodynamic model, resulting in a model called CH3DZ-FM. Field data collected by ERDC for the New Orleans District are being employed to validate the numerical model. RESERVOIR CIRCULATION Lake Washington - CHT assisted the US Army Engineer Research and Development Center (ERDC) in the development and application of a three-dimensional (3D) hydrodynamic model of Lake Washington to provide flow fields to a 3D water quality model of the lake. Lake Washington is located near Seattle, WA. The CH3DZ hydrodynamic model was applied on the grid shown (with many vertical layers) for the years of 1995-97. During this period, sufficient data were available to set all freshwater inflows and wind forcing, along with the water surface elevation at the Hiram M. Chittenden Locks leading into Puget Sound. In addition, temperature data were available at several stations throughout the lake to aid in model validation. Velocity data collected in the 1970’s were employed to demonstrate the ability of the 3D hydrodynamic model to accurately compute the movement of lake waters during different periods of the year. STORM SURGE Hilton Head Island and Vicinity Storm Surge Study - CHT is conducting this study with the Charleston, SC District of the US Army Corps of Engineers. The purpose of the study is to compute storm surge frequency-of-occurrence relationships that reflect tidal phasing as well as both tropical and extratropical storm events. The computational grid of the study encompasses the eastern Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. High resolution was provided in the Hilton Head Island study area such that the minimum grid spacing is on the order of several hundred meters. Recent high precision bathymetry data have been interpolated onto the refined portion of the global grid. Tides and historically occurring tropical and extratropical storm events are being simulated over the grid domain with peak surge values archived at selected locations in the study area. These data will be input to the EST to develop frequency relationships for each location. PHYSICAL MODELS Olmsted Locks and Dam, Ohio River Study - CHT provided technical guidance and assistance to ERDC on the concept of using 1:60 section model and 1:120 general movable-bed model of Olmsted Locks and Dam, Ohio River. CHT partner, Tom Pokrefke, reviewed the testing program, met with the contractor, and provided guidance on data requirements, data measurements and analysis, and evaluation of various testing schemes. The Olmsted Locks and Dam project is presently under construction using an innovative, never performed, at this scale in the US, in-the-wet construction method. The test results from the section and general models will be used almost immediately to provide the contractor with specific construction sequences and potential problems during float-in, “sinking,” and placement. RIVER ENGINEERING Ohio River Bank Stabilization Study - CHT was part of a five-man team which conducted a site visit, discussed and developed alternatives, prepared design plans with justifications, and prepared a final report for the Ohio River at St. Marys, West Virginia. CHT worked with the US Engineer Research and Development Center (ERDC) in Vicksburg, MS and conducted the study for the Huntington District of the US Corps of Engineers. Timely completion of this study was critical since repair efforts had already started, but the District had major questions of the adequacy of repairs, as well as impacts to the adjacent Middle Island Creek, the downstream Ohio River channel, the scheduled construction by the West Virginia Department of Highways of a new bridge to Middle Island, and on Middle Island, which is owned and managed by the US Fish and Wildlife Service as a National Wildlife Refuge. DREDGED MATERIAL DISPOSAL Palos Verdes - CHT assisted ERDC in a field pilot study of in situ capping of contaminated bottom sediments on the Palos Verdes Shelf off the coast of California. CHT’s effort related to the modification and resultant application of the STFATE model for predicting the short-term fate of dredged material released in open water. STFATE was applied to simulate several placement operations that were monitored to assess the ability of STFATE to accurately compute the speed of bottom surges resulting from individual placement operations. Columbia River - CHT assisted the Pacific National Laboratory in a study to assess the impact of dredged material disposal in the Columbia River on bottom dwelling crabs. STFATE was modified to compute the impact pressure force and the spatially and time varying bottom shear stress field resulting from the bottom surge created by the impact of the dredged material with the river bottom. Many scenarios were then run for various water depths and material release times. FIELD DATA ANALYSIS Atchafalaya Bar Channel Fluff Field Study - CHT assisted the Coastal and Hydraulics Laboratory, ERDC, and USACE District, New Orleans, in the interpretation of a large and complex field data set collected by ERDC in and around the area where fluff and fluid mud have caused chronic channel maintenance problems. Instrumentation included both fixed ADP and moving ADCP for currents, wave and water-level pressure gauges, water column samplers and profilers, fluid mud and bed samplers, suspended sediment and salinity monitors, and acoustic survey equipment. Data were analyzed to identify factors contributing to the accumulation of fluff in the channel and possible operational, structural and non-structural remedial measures. TECHNICAL REVIEW CHT has a strong reputation for providing technical review of studies conducted by others. Examples include technical reviews for the ERDC on Savannah River modeling conducted by ATM, Inc. and for Versar, Inc. on the “Cumulative Impacts Analysis Report for Uniform National Discharge Standards”. Drs. Johnson and Teeter are currently serving on various Model Evaluation Groups (MEG’s). These include MEG’s for modeling studies in Florida Bay, the Indian River Lagoon in Florida, and in Chesapeake Bay. In addition, CHT Associates Drs Martin and Dortch have served on many technical review panels. These include Delaware Bay TMDL Study, Gulf of Mexico Hypoxia Study, South Florida Ecosystem Restoration Study, etc. Computational Hydraulics and Transport LLC. 2006.