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Why did Figure 8 Island want to install a terminal groin?

Three other beach communities are seeking permits for their own structures; Figure Eight Island in New Hanover County, and Holden and Ocean Isle Beaches, both in Brunswick County, also want a terminal groin to trap sand, slow erosion, and lessen the frequency of expensive beach nourishment projects.

Why did Figure 8 Island want to install a terminal groin?

Three other beach communities are seeking permits for their own structures; Figure Eight Island in New Hanover County, and Holden and Ocean Isle Beaches, both in Brunswick County, also want a terminal groin to trap sand, slow erosion, and lessen the frequency of expensive beach nourishment projects.

What does a terminal groin do?

In the most basic sense, a terminal groin is a type of rock wall built on the shoreline, extending into the water that are used to help grow beaches and slow erosion.

Why is it called a terminal groin?

They are often built in a series of parallel structures on one section of beach and can be made of wood, concrete, steel or stone. Terminal groins are relatively new concoctions. They are the name proponents have given to small jetties built at inlets — the terminus of islands.

What would the cost of the terminal groin be?

A steel groin with concrete fascia and cap is approximately $4,000 – $5,000 per linear foot for groins up to 15 – 20 feet in height. Steel groins can be reinforced for use in greater depths of water; however, this is typically cost prohibitive to use for depths greater than 20 feet.

Why are beach groins bad?

The negative impact of groins on downdrift shorelines is well understood. When a groin works as intended, sand moving along the beach in the so-called downdrift direction is trapped on the updrift side of the groin, causing a sand deficit and increasing erosion rates on the downdrift side.

What is the difference between a jetty and a groin?

Jetties. Jetties are large, man-made piles of boulders or concrete that are built on either side of a coastal inlet. Whereas groins are built to change the effects of beach erosion, jetties are built so that a channel to the ocean will stay open for navigation purposes.

What is an ocean groin?

Groins are shore perpendicular structures, used to maintain updrift beaches or to restrict longshore sediment transport. By design, these structures are meant to capture sand transported by the longshore current; this depletes the sand supply to the beach area immediately down-drift of the structure.

Why do beaches have groynes?

The purpose of a groyne is to stop sand and pebble movement along a stretch of coast. It does this by trapping beach material which helps build up a larger section of beach in front of an area that’s experiencing coastal erosion.

How much does it cost to build a groin?

How could this terminal groin the beach on the other side of the inlet on the West?

What’s at stake. Damage and erosion: A terminal groin at the east end of the island could impose navigational hazards and influence, in a negative manner, the beach on the other side of the inlet at the west end of Holden Beach.

What is the major drawback of groins?

The problem with groins is that they trap sand that is flowing to a neighboring beach. Thus, if a groin is growing the topographic beach updrift, it must be causing downdrift beach loss.

What happens to a beach located down the coast from a groin?

What happens to a beach located down the coast from a groin? groins deprive beaches down the coast, also eroding it. Why does anchorage behind breakwater have to be dredged? to prevent the current’s movement and slow the ability to move sediment if left alone.

Are terminal groins a good idea for Figure Eight Island?

A number of beach communities, led by Figure Eight Island, have long lobbied for an exception to the legislative ban to allow “terminal groins.” They were trying to sell the notion that these small jetties at the end of island will control erosion and reduce beach re-nourishment costs.

Which islands have received permits for a terminal groin so far?

Four permit applications for construction of a terminal groin have been submitted to the federal U.S. Army Corps of Engineers’ district office: Figure Eight Island, Ocean Isle Beach, Holden Beach and Bald Head Island. Only Bald Head Island has acquired a permit from the Corps and the first phase of their terminal groin is complete.

What is the function of terminal groins?

Terminal Groins. A jetty is built perpendicular to the shore, usually at inlets, and extends out into the water. It blocks the current moving down the beach, called the longshore drift, and holds sand in place and prevents the end of the island from washing away and the channel through the inlet from filling with sand.

What happened to terminal groins in North Carolina?

The North Carolina Senate passed a bill in 2008 to allow “terminal groins” but it went nowhere in the North Carolina House. In an attempt to break the logjam, the legislature ordered the Coastal Resources Commission to conduct a study on “terminal groins.”