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On October 23, the Minerals Management Service (MMS) sponsored a workshop hosted by the Delaware Geological Survey (DGS) on locating and using offshore sand resources for nourishing eroding beaches on the Atlantic coast.
Coastal erosion, involving land loss, property damage, and sometimes loss of life, is a major issue for developed areas of all 30 U.S. coastal States and territories, as well as for much of the world's low-lying or developed coastal regions.
The causes of erosion are complex. Mostly, coastal erosion is caused by natural processes, such as storms and relative sea-level rise; but increasingly, human causes, such as inlet jetties, seawalls, dams, and dredging, are exacerbating coastal erosion by depleting sediment input and blocking sediment transport at the coast.
Coastal erosion is likely to increase and have additional impacts on society as sea-level rise accelerates and storminess increases over the 21st century in response to climate change that is already underway.
One preferred method of mitigating beach erosion, at least temporarily, is beach nourishment. In this method, sand is dredged from offshore, pumped onto the beach, and engineered to build up the beach berm and dunes to enhance storm protection and recreation potential.
Although beach nourishment is being increasingly used to mitigate erosion, it is temporary and expensive, and large volumes of high-quality sand are needed over the 50-year life span of most such projects. Because onland sand and gravel resources are limited, marine sand bodies on inner-continental-shelf areas are becoming increasingly attractive sources of sand.
The recent Offshore Sand Workshop was convened so that participants could share information about offshore sand resources in the mid-Atlantic region (Virginia to Maine) and discuss environmental issues and needs for future studies.
Speakers from six States, as well as the MMS and the U.S. Army Corps of Engineers, were on the agenda. S. Jeffress Williams, of the U.S. Geological Survey (USGS)'s Woods Hole Science Center, summarized results from the USGS' Marine Aggregate Resources and Processes study in a talk titled "Insights to Seafloor Sedimentary Character, Aggregate Resources, and Processes of U.S. Continental Margins" and presented two posters.
The workshop agenda and copies of the PowerPoint slides from Jeff's talk and others are available as pdf (portable document format) files (click on link "workshop_pdf_files").
in this issue: Seamount Environments off California
Mid-Atlantic Offshore Sand Resources
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