After hearing inaugural results of an annual survey tracking sand movement on New Hanover County’s beaches, coastal leaders agreed the surveys will ultimately help them tackle beach management projects more efficiently and effectively.
Data collected by Raleigh-based engineering firm Moffatt & Nichol was presented during a Nov. 12 Wilmington-New Hanover Port, Waterway and Beach Commission meeting.
The first round of results was interesting, said county shore protection coordinator Layton Bedsole, but the surveys will yield new understanding about how sand moves on beaches and in inlets over time.
“This is a great building block for the county for years to come,” Bedsole said.
Moffatt & Nichol studied cross-sections of the beach strand, from the top of the dune to the outer sandbar, on Wrightsville Beach, Masonboro Island and Pleasure Island during March and May. To help interpret the first round of numbers, results of a 2009 shoreline mapping project performed by a U.S. Army Corps of Engineers contractor were presented in tandem with the 2014 data.
The initial numbers suggest erosion on all county beaches, except for Fort Fisher, at an average countywide rate of 6.6 cubic yards of sand per foot per year, a conclusion that underlines the need for and success of ongoing renourishment projects.
Wrightsville Beach Town Manager Tim Owens said the results confirmed some known areas of erosion on the beach, especially on the north and south ends near the inlets, but he hesitated to draw any conclusions based on only two sets of data.
“This first year is not a blockbuster-type statement. As we get more data, we’ll better understand where the sand is going and if we need to do anything different,” Owens said.
The central portion of Wrightsville Beach, roughly from the Blockade Runner to Sand Dollar Lane, receives the majority of sand deposited during renourishment. Owens suspects sand drifts north and south toward the inlets between renourishment cycles. A few more years of shoreline mapping surveys will hopefully prove or disprove that and other ideas about sand movement on Wrightsville Beach, giving stakeholders information needed to better maintain beaches with limited resources.
“If we do this every year, we’ll get a better picture. I think that’s the take-home that I got,” Owens said. “We spend a lot of money on this beach and we need to know what’s going on year to year. We started that effort, and if we keep doing it, it’ll pay dividends in the future.”
Moffatt & Nichol also collected data on sand movement in Masons, Masonboro and Carolina Beach inlets, which was not discussed during the presentation because no historical data exists to compare to the first year of results.
The surveys cost $150,000 annually, absorbed by the county’s room occupancy tax revenues. A request for the 2009 corps data included in the final report tacked an additional $50,000 onto the total bill.
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