Sunday, July 21, 2024

Nearly 1K flooding events in 10 years spark needed improvements at Battleship NC

The USS Battleship NC sits along a low-lying area of the Cape Fear River, leading to constant tidal flooding; to remedy the impacts, staff is undergoing a Living with Water project to incorporate ecological solutions to reduce high waters. (Port City Daily/file)

NEW HANOVER COUNTY — A significant spike in tidal flooding at one of the Cape Fear region’s most visited historic attractions has led to a reduction in visitors and in turn, the need for biological intervention.

The USS North Carolina, the most highly decorated American battleship of World War II, is situated along the west banks of the Cape Fear River. It’s undergoing a $4.5-million Living with Water project in an effort to reduce flooding by using ecological solutions, including a living shoreline and bioswale through the parking lot. 

Development director Terry DeMeo researched historic tidal levels on the Battleship NC property, across from downtown Wilmington and adjacent to the low-lying Eagle’s Island. The tide in this area fluctuates daily by 4 or 5 feet. She found flooding events — measured by the National Oceanic and Atmospheric Administration as 5-1/2 feet or higher — have increased by 6200% since the 1940s.

In the ‘40s there were 16 flooding events on the Battleship NC property over the decade and by the 2010s that number spiked to 997.

In 2020, high tides around the Battleship — the highest ground only a few feet above sea level — rose to 5-1/2 feet or more during 174 days of the year.

DeMeo explained the issues first became apparent in 2015, as the access road — North Carolina Road — and its 500-space parking lot were flooded even when it wasn’t storming. She said for example, if there’s wind coming up the Cape Fear River it pushes the water onto the property more quickly.

“So, if our road is flooded or our parking lot is flooded, then it causes people to be uncertain about driving through the water,” she said. “So, really, the coastal flooding was affecting our business model and our livelihood.”

DeMeo said the loss of revenue can’t really be tracked, as many variables impact their visitation numbers as is. 

“You don’t ever know the number of people who are visiting from like Ohio,” she said, “for instance, who come to the top of our access road and see water on the road and say, ‘I don’t think so.’ And turn around and drive away.”

As stated on the Battleship NC Living with Water story map: “If the public cannot visit or decide not to visit, the Battleship is in financial jeopardy.”

Though typically the battleship welcomes 200,000 to 250,000 people annually and is self-sustained.

“The battleship functions as an enterprise of the state of North Carolina,” she said. “That means we receive no taxpayer dollars out of the general budget of the legislature. So, we are required by statute to pay for all our operations.”  

The Living with Water project is fully funded though through four grants — North Carolina Land and Water Grant, National Fish Wildlife Foundation, Kerr McGee Superfund Site settlement, and Fish and Wildlife Service — as well as a $1 million state appropriation for the non-nature-based construction.

The first phase will remove the portion of the parking that floods most frequently, about 2 acres. It will reduce its lot from about 500 to 350 spots.

“The ones we’re losing have experienced such chronic flooding, people tend not to park there anyway,” DeMeo said.

The lot renovation also requires moving infrastructure, such as utilities and installing new lights.

The removed portion of impervious surface will then be replaced with a wetland to help capture the tide waters. DeMeo explained the wetland will provide a place for the water to flow to, help facilitate percolation, and guide the waters back to the Cape Fear River.

The work also includes softening of the ship’s berth, which is basically the shoreline of the river. The eroded portion of the shoreline will be removed and replaced with an 800-foot estuarine living shoreline. It will consist of vegetation and a combination of hard surfaces like rock sills and oyster reefs to stabilize the area. It will also help restore fishery habitat.

The portion of the parking lot that will remain will be elevated to provide safer parking, DeMeo said, by installing down the middle a bioswale — a channel designed to direct water runoff. The artificial stream will be vegetated with native grasses and plants, and also help offset the tide waters.

“It’s effective in infiltration as well,” DeMeo added.

Together the improvements will improve traffic flow and pedestrian safety.

When Battleship staff first realized the flooding was consistent and extreme, they engaged NOAA. The federal agency conducted hydraulic studies and installed water-level sensors to confirm it was tidal in nature.

“[T]hey were able to determine that by salinity measures at the various monitoring locations they had,” DeMeo said.

NOAA also found the flooding mimics what’s occurring at the tidal gate at the foot of the Cape Fear Memorial Bridge, further corroborating the flooding was due to rising tides and not necessarily storm events.

Battleship NC staff engaged design engineering firm Moffat and Nichol in 2018 for preliminary work. The company went under contract in 2020 to design the needed site improvements. 

Construction drawings are finalized and the Battleship NC is authorized to send the work to bid this summer. Construction is expected to begin later this year — specifically post-hurricane season — and take six to seven months.

DeMeo said during construction, the Battleship will remain open; renovations will be phased to avoid disruption to visitors.

The goal is for everything to be completed by July 2024. Staff will then begin to monitor the tides for effectiveness of the installed elements.


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