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 Shoreline vulnerability is depicted in this illustration of Cape Cod National Seashore, Massachusetts, produced by the USGS project in 2001. Erosion rates, sea level rise rates, storm surge, and other factors were evaluated to determine the susceptibility of the park shoreline to inundation and change. U.S. Geological Survey
Rebecca Beavers |
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 By Rebecca L. Beavers Shoreline erosion, lower water levels in the Great Lakes, saltwater intrusion in groundwater supplies, and inundated wetlands and estuaries are serious concerns along more than 7,000 miles of shoreline managed by the National Park Service. Potential climate change–induced impacts such as these confront more than 80 coastal park units. To obtain the information needed to address these challenges, the U.S. Geological Survey National Assessment of Coastal Change Hazards project (USGS project) continued efforts to quantify coastal change and created map products in 2001. These USGS products will help park managers understand and predict emerging threats to fragile coastal resources and develop appropriate management responses. The USGS project has implemented new technologies that have vastly improved the quantity and quality of coastal change data. For example, emergent lidar technology, a laser version of radar, makes cost-effective data available nationally. The acquisition of shoreline position data is feasible for numerous parks; however, the analysis of large, complex raw lidar data is not practical at parks with small natural resource management staffs and competing priorities. Through the USGS project, coastal parks like Assateague Island National Seashore, a pilot park for the project, are receiving assistance with analyzing lidar data and developing maps. In 2001 the USGS project worked with Assateague Island National Seashore to develop high-resolution GIS topographic layers and digital aerial photomosaics for landscape monitoring and habitat mapping. Impacts of feral horse grazing on dune vegetation and the extent of piping plover brood habitat were quantified and used to make resource management decisions. Lidar baseline information is also used to evaluate historic shoreline changes. Accurate rates of historic change are critical to defining human vs. natural changes along NPS-managed shorelines and developing appropriate management responses. For example, managers at Assateague have used the information developed through the project to evaluate previous shoreline engineering projects and critically evaluate plans for an island restoration project. “Lidar data enhances our ability to manage a changing island and make intelligent decisions,” according to Carl Zimmerman of the national seashore. Defining the physical response of shorelines to sea-level rise is another challenge facing NPS managers as they try to protect complex coastal systems. Global sea level has risen 4–8 inches (10–20 cm) in the past century and current models suggest this rise is likely to accelerate. For example, the level of the Great Lakes is projected to decline by 3–10 feet (1–3 m) in the next 50 years. Implementing protection or retreat strategies for vulnerable coastal resources requires consideration in areas where beaches and wetlands migrate inland to survive elevated sea levels and increased storm surges. To improve understanding of sea level change, the USGS project will continue to assess the spatial distribution of specific risk types, including erosion, shoreline retreat, and inundation. The project will produce park-specific vulnerability maps and GIS data layers. During 2001, the USGS used information on coastal geomorphology, shoreline erosion rates, sea level rise rates, storm surge, wave height, tide range, and regional coastal slope to develop the Coastal Vulnerability Index for shorelines at Cape Cod National Seashore (see map), Olympic National Park, and Gulf Islands National Seashore. Olympic National Park used USGS project products to identify vulnerable infrastructure and implement plans to relocate the Kalaloch Lodge. In 2002, this cooperative project will map the Coastal Vulnerability Index at 10 additional parks with Fee Demonstration Program funding. The lidar technology used to define coastal change and climate change–induced impacts has been developed in the last decade. New technologies are increasingly able to provide the types of detailed information park managers will need to protect fragile coastal resources as the USGS project has begun to demonstrate. In the future, partnership efforts like the USGS project will yield important information that will allow the National Park Service to protect natural shoreline conditions, recreation opportunities, cultural and historic resources, and park infrastructure. |
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This material is from Natural Resource Year in Review--2001, published by the National Park Service, U.S. Department of the Interior, in May 2001 (publication D-2255) /YearInReview/yir/yir2001/04_marine/_04_4_beavers.html Last Updated: |
