Dune management discussed in Duck

Published 12:57 pm Wednesday, June 26, 2024

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During the June 19 Duck Town Council mid-month meeting, council members approved an updated public safety software system, authorized budget amendments to correct for some unforeseen costs during this fiscal year, moved money from a closed account to the town’s capital beach nourishment account, and heard a lengthy presentation on dune management techniques.

Taking a majority of the afternoon meeting time, Nick Cohn of the Army Corps of Engineers Field Research Facility talked about how best to manage dunes with fences and vegetation on the beach.

According to Cohn, dunes are global features that intermittently grow and erode. Vegetation can encourage dune growth and in turn reduce wave-driven erosion over short periods of time.

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During his talk, Cohn pointed out that while he was providing a lot of terminology, much of it was helpful toward understanding the dynamics of the presentation.

According to Cohn, beach-grass and sea oats have the highest survival rates, although the growth rate for sea oats is reduced after about two years.

That led Brenda Chasen to ask how the town could maximize its plantings.

While there is again no one answer, Cohn suggested mixing the plant species used since “that seems to help.”

Cohn also covered different vegetation and planting techniques available, adding that there is no one correct dune structure since erosion activity is not the same everywhere.

He then went on to say that sand fencing can similarly promote dune growth and, since the results can be seen quicker than from planting vegetation, that fences are an effective way of building new dunes.

Sand fence location can determine the dune form with different fence configurations producing different dune shapes. One drawback is that sand fencing is not effective in areas with little or no wind.

Looking at the long-term risks, storms are projected to grow in frequency and intensity. Cohn added that storm tracks are also moving farther north.

Effects of construction and development near oceanfront dunes was discussed briefly. In most cases there are changes to ground moisture and aquifers as well as bringing more people to trample the dunes and any grasses planted.

As an information only presentation, council took no action at the end of the presentation.

The next scheduled Duck Town Council meeting will be a regular session meeting Wednesday, July 3 at 1 p.m.