USGS Coastal and Marine Geology Program Project Descriptions (Sample)
Theme 1: Environmental Quality and Preservation
Fundamental Environmental Studies
Large-scale Coastal Modeling Project
Richard P. Signell and Jeffrey H. List
U.S. Geological Survey
384 Woods Hole Rd.
Woods Hole, MA 02543
(This section can be taken almost verbatim from the National Plan) The sediments on the floor of many coastal areas, lakes, and estuaries within the U.S. and on areas of the continental shelf, particularly near urban centers, contain pollutants. Heavy metals, radioactive waste, organic chemicals, and nutrients have been introduced through natural processes, by intentional disposal, and by accidental spills. The contaminants are derived from sources such as industrial discharge, sewage treatment plants, agricultural and urban run-off, and atmospheric deposition. Many contaminants attach to sediments or behave as sediment-like particles.
The behavior of polluted sediment is strongly influenced by sea-floor geology and sediment transport processes, [like waves, storms, and currents?]. For example, many pollutants chemically and physically bind to fine-grained sediment. Mobilization and transport of the "host" sediment by waves and currents results in movement of the pollutants.
The presence of such materials and their movement into certain areas have created problems associated with public health and safety, viability of biological resources, and use of recreational areas. There are economic implications as well; for example, dredging, essential to the viability of many U.S. ports, requires environmentally-sound disposal of contaminated and non-contaminated material.
How the USGS is addressing this issue
To better understand pollutant accumulation and transport, the USGS will
- study how sea-floor sediments and associated pollutants are transported
- develop models that will help predict where sediment and associated pollutants might be carried
Accomplishments to date
(This section should be at an 8th grade comprehension level. This sample needs more simplification) Initial work on building the sediment transport modeling system focused on integrating a wave model with a 3D coastal circulation model and on developing analysis and visualization tools for assessing data generated by the models.
Bottom orbital velocities and mean wave periods predicted by wave model were combined with observed bottom currents predicted by the circulation model to calculate bottom friction due to waves. The increased friction was found to significantly reduce the coastal sediment transport during storms in Massachusetts Bay. Also, a method was developed for evaluating the long-term control of wave orbital velocities on the large-scale sediment distribution patterns in estuarine environments. This method was applied, in conjunction with circulation model results, to an ongoing study of the sediment and bottom-type distribution in Cape Cod Bay, Massachusetts, resulting in a much better understanding of the controlling physical processes.
Analysis and visualization routines developed for the wave model and the circulation model using MATLAB have greatly improved understanding of the model results. The use of MATLAB enables uniform access to and analysis and visualization of model-generated data from Mac, PC and UNIX workstations with no specialized graphics hardware.
(This section should be at an 8th grade comprehension level. This sample needs more simplification) The principal goal is to develop cohesive and non-cohesive sediment transport sub-models for the existing circulation model and wave model. This will be accomplished through cooperative work with private-sector scientists who have recently developed a cohesive sediment transport sub-model that interfaces with the circulation model. The cohesive sub-model is derived from work done by scientists at the University of California at Santa Barbara. The USGS will greatly benefit from private-sector expertise in practical application of sediment transport modeling and can begin to test different processes such as bed erosion, deposition, and consolidation. The results will be made available to the research community.
Sediment sub-models currently used by operational sediment transport models will be surveyed, and information for those presently in use at institutions such as the Delft Hydraulics Lab in the Netherlands, the University of Florida, and the U.S. Army Corps of Engineers Waterways Experiment Station, will be compared with USGS findings.
Testing of wave-prediction models will continue, including the wave model already in use and another developed at the University of Delaware. The models will be compared and validated using actual field data collected as part of the USGS Marine and Coastal Geology Program's Massachusetts Bay and Lake Pontchartrain projects.
Efforts will continue to make the increasingly complex codes more usable, maintainable and better documented. The codes will be placed under a new system to improve handling of updates and revisions. The codes will also be modified so that options may be more easily specified.
- University of California at Santa Barbara
- Delft Hydraulics Lab
- University of Delaware
- University of Florida
- U.S. Army Corps of Engineers
Knebel, H.J., Rendigs, R.R., List, J.H., and Signell, R.P., 1995, Seafloor environments within Cape Cod Bay: fine-grained sediment dispersal within a large coastal embayment, Abstracts, Geological Society of America Annual Meeting, New Orleans, p. 202.
Knebel, H.J., Rendigs, R.R., List, J.H., and Signell, R.P., in press, Seafloor environments within Cape Cod Bay: temporal and spatial variability of processes within a large coastal embayment, Marine Geology.
List, J.H. and Signell, R.P., 1995, Characterizing the climate of wave orbital velocity within coastal regions, AGU/ASLO meeting '96, San Diego, submitted.
List, J.H., and Terwindt, J.H.J., 1995, Introduction: large-scale coastal behavior. Special issue, Marine Geology: 126, 1-3.
Signell, R.P., List, J.H., and Jenter, H.L., in press, The effect of wave-enhanced bottom friction on storm-driven circulation in Massachusetts Bay, in : Buoyancy Effects and Transport Processes in Estuaries and Coastal Seas, JGR Press.
Planned products should be listed under current year activities.
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