The recent water marshes of Currituck Sound are important for birds and folks alike, offering globally necessary habitat for waterfowl and serving as a water filtration and erosion management system for communities. However these identical wetlands are additionally going through intense stress from rising seas and encroaching improvement.
That’s why Audubon is enterprise a sequence of marsh restoration pilot initiatives at our Donal C. O’Brien, Jr. Sanctuary at Pine Island. Due to funding from the Nationwide Fish and Wildlife Basis’s Nationwide Coastal Resilience Fund, the ultimate design of the initiatives is beginning to take form.
The work ought to assist stem erosion and even construct again the marsh in locations that want it most. A latest evaluation historic and present-day photographs discovered that, during the last 50 years, the marsh had receded by greater than 300 toes in among the most severely affected parts of the undertaking space.
The work is a part of a broader Marsh Conservation Plan developed by Audubon and the Currituck Sound Coalition, with the last word purpose of defending and reviving marsh habitat on this fast-changing ecosystem.
As we put together to step into the subsequent part of this undertaking, right here’s a deep dive into what it is going to seem like.
Utilizing Christmas timber to cut back erosion
For this pilot undertaking, we’ll be putting in pilings within the water in entrance of marsh islands. Pine timber will then be positioned in between the pilings, making a buffer that helps take up wave power earlier than it reaches the marsh.
This system is useful as a result of it makes use of pure materials and permits sediment to maneuver via the buffer. It has been examined via formal, permitted initiatives on barrier islands in North Carolina and has been used to efficiently defend marshes alongside the Gulf Coast. It additionally presents a possibility to interact neighborhood members in recycling their Christmas timber.
The normal method: coir logs
Coir logs are made from woven, biodegradable materials and resemble a rolled up carpet. Setting coir logs on naked mud simply in entrance of marsh islands will help to dampen the pressure of waves. This can be a normal and cost-effective erosion management approach.
Just like the Christmas tree breakwater undertaking, this undertaking will happen on the jap aspect of the sound. For each, we’d wish to see sediment accumulate behind the buffer, ultimately supporting new marsh grass development. However even when that doesn’t happen, the initiatives ought to assist management erosion of what’s already there.
The query for the coir logs and the Christmas tree breakwater is how properly they may maintain as much as sturdy winds and storms on the sound. These pilot initiatives will give us a clearer thought of what to anticipate.
Rebuilding the marsh from the mud up
Probably the most revolutionary approach we’re enterprise is named thin-layer placement, which includes dredging sediment from one space and making use of it in skinny layers on the marsh floor. The purpose is to actually rebuild the marsh in locations the place it has disappeared.
This undertaking will happen at two websites on the western aspect of the sound, in areas of the marsh that undergo from “ponding.” Ponding happens when rising water ranges slowly drown inside areas of the marsh over time.
Skinny-layer placement has solely been tried at a number of small-scale marsh restoration initiatives within the state. Nonetheless, this method has been used efficiently in different states like New Jersey and Louisiana. Our purpose is to match its effectiveness and value with different restoration methods in North Carolina.
Investigating the specter of an invasive swamp rodent
Should you spend sufficient time on Currituck Sound, you’ll get a glimpse of enormous rodents swimming throughout slender channels within the marsh, their snouts raised simply above the water. These are nutria, a species that’s native to South America and is a bigger relative of the muskrat.
Nutria are thought-about an invasive species in Currituck Sound. As they transfer via the marsh, foraging and consuming the roots of grasses, they go away a community of deeply lower paths of their wake that additional intensify marsh loss to sea stage rise. We’re taking a preliminary take a look at how the nutria may influence marsh restoration efforts by putting in fencing round a few of our thin-layer sediment websites, whereas preserving others as management websites.
