Beach Erosion Mitigation and Sediment Management Alternatives at Wallops Island, VA
Williams, Greggory G.
Swean, Jerry W.
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The Goddard Space Flight Center, Wallops Flight Facility (WFF), is located on the eastern shore of Virginia facing the Atlantic Ocean. The island has experienced erosion throughout the six decades that NASA has occupied the site. Near the south part of the island, at the Mid-Atlantic Regional Spaceport (MARS) spaceport, shoreline retreat from 1857 to the present averaged about 3.7 m/year. Further south, adjacent to Assawoman Inlet, retreat exceeded 5 m/year. Since the early 1990s, part of the island has been protected with a stone rubblemound seawall, a replacement for an older wood wall that deteriorated. Although the seawall has temporarily fixed the shoreline position, the structure is being undermined because there is little or no protective sand beach remaining and storm waves break directly on the rocks. The south end of the island is currently unprotected except for a low revetment around the MARS launch pad. As a result, NASA officials are highly concerned that launch pads, infrastructure, and test and training facilities belonging to NASA, the U.S. Navy, and the (MARS) spaceport, valued at over $800 million, are increasingly vulnerable to damage from storm waves and that the foundations of structures and the Unmanned Autonomous Vehicle (UAV) runway may be undermined as the beach continues to erode. ERDC and U.S. Army Engineer District, Norfolk, have developed a shore protection plan to protect Wallops Island from ongoing beach erosion and storm wave damage incurred during normal coastal storms and northeasters. The key aspect of the plan is that the beach will have to be rebuilt with a sand fill along the entire island. The ultimate purpose will be to move the zone of wave breaking well away from the vulnerable infrastructure. This plan is not intended to protect against inundation and other impacts during major hurricanes and exceptional northeasters, when water levels can rise several meters. The more comprehensive of two alternatives includes beach fill and the construction of sand-retention structures such as detached breakwaters. Despite the higher initial costs, structures will probably reduce life-cycle costs because of reduced requirements for renourishment volumes.