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Scope of the Study Adding Value with LIDAR Study Activities Agency Roles and Responsibilities |
 Over the
past century, the beaches of the Columbia River littoral cell have
accreted substantially, providing an expanding land mass seen as
favorable to development. Recently, however, that trend of
accretion has slowed throughout the region and has reversed in
certain "hot spot" areas, yielding dramatic erosion rates and the
potential for hundreds of millions of dollars in damages. In the
mid-1990s, there was much speculation about the cause(s) of
the trend reversal, but virtually no scientific or technical data
had previously been collected to serve as a basis of comparison to
current conditions.
To meet the need for information, a federal-state-local cooperative research program, the Southwest Washington Coastal Erosion Study, has been initiated to examine coastal geology, coastal processes, and natural hazards in order to predict and avoid emergencies along the southwest Washington coast. The Study is codirected by the U.S. Geological Survey (USGS) Coastal and Marine Geology Program and the Washington Department of Ecology's Coastal Monitoring & Analysis Program (CMAP), with active participation of local communities in Pacific and Grays Harbor Counties. Solid technical data will serve as a foundation for understanding the evolution of the littoral cell and enable predictions of future coastal change. Translating Study results into management tools and information products will help local communities identify cost-effective solutions to current coastal crises, manage resources, protect life and property, and prevent damage from future erosion. Without the necessary information, communities and agencies can not engage in effective land use planning and decision making, and instead are forced to respond on a crisis-by-crisis basis to erosion events.  Return to Top
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The Southwest Washington Coastal Erosion Study is documenting historical and current shoreline change rates to assess and, ultimately, predict coastal change at time and space scales relevant to coastal management (decades and tens of kilometers). Two key research components of the Study include shoreline change and sediment budget analyses. Shoreline change is being quantified by converting historical paper maps and aerial photographs to geographic information system (GIS) data layers. Quantitative sediment budgets for the littoral cell are being developed for historical and modern time periods. The sediment budget analysis details sediment sources and sinks, the total volume of sediment in the littoral system, and its rate and direction of transport.
Historically the Columbia River has been the main supplier of sediment to the beaches between Tillamook Head, Oregon and Point Grenville, Washington. This 165 kilometer stretch of coast is known as the Columbia River littoral cell. Sand transported down the Columbia travels primarily northward from the mouth of the river, replenishing the coastal beaches along the way. At the onset of the Study, one hypothesis for the recent erosion trend was that the 12 major dams along the river's path, and hundreds of others throughout the drainage basin, were slowing the water flow enough to cause a substantial decrease in sediment reaching the ocean. While this is most certainly true, a major finding of the Study indicates that shorelines along much of the littoral cell are still responding to the jetties at Grays Harbor and the Columbia River that were installed approximately 100 years ago.
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LIDAR data was collected along the Columbia River littoral cell in both 1997 and 1998 as part of the Airborne LIDAR Assessment of Coastal Erosion (ALACE) project in order to quantify the impacts of one of the strongest El Niños on record. The regional nature of the LIDAR data made it an ideal addition to the existing data collection efforts of the Study. LIDAR data, combined with beach monitoring data and historical bathymetric and topographic charts, will help scientists understand the changes that have occurred as the littoral cell has evolved over time. LIDAR data make it possible to derive a highly accurate digital elevation model (DEM) of the entire study area. This DEM can be used to measure dune heights, beach slopes, and sediment volume in the barriers. Repeat LIDAR surveys would assist in quantifying changes in these beach state parameters, essential information for coastal management and decision making.
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The Study is comprised of a multidisciplinary research team. Listed below are some of the key activities that are underway or contained in the study work plan:
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Federal, state, and local agencies contribute their resources and capabilities where they are most needed. Much of the work is jointly conducted with partners and investigators providing expertise to accomplish specific tasks along the way.
The United States Geological Survey (USGS) and funded collaborators are responsible for investigating sediment budgets, framework geology, and inner continental shelf processes. The USGS is applying its expertise in regional scale oceanographic and geologic processes to guide and integrate the research.
The Washington Department of Ecology is conducting specific research tasks to examine changes in beach form and shoreline position. Ecology also serves as the link between the federal and local efforts and is assisting in the technology transfer process to the coastal communities.
Local agencies are primarily responsible for identifying products needed by the communities in order to best use the data in resource management and land-use planning. Local groups, represented through a consortium, serve in a substantive advisory capacity to the Study, participating in the development of specific objectives and in the ongoing review of Study progress. Local groups also engage in long-term planning in collaboration with the state and federal agencies.
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