CHATHAM – Just as panelists were discussing the dynamic nature of the town's shoreline during a forum at the community center Saturday morning (see the story on page 14), Mother Nature was proving their point by creating a new break in North Beach Island.
By Sunday the northernmost tip of the island was an isolated sandbar and the new cut was more than 100 feet wide and deep enough for boats to navigate, though extensive shoaling caused a fishing boat to get stuck there Monday.
The development is not unexpected and is part of the evolution of the north inlet, formed in a storm on Patriot's Day in 2007. It could, however, signal the beginning of a shift in the inlet dynamics of the system, with the 2007 inlet taking more of the flow of water between Pleasant Bay and the Atlantic and becoming the dominant inlet, a position up until now held by the 1987 inlet across from Lighthouse Beach.
If so, it could mean a quicker and easier passage to the ocean for commercial fishermen based at nearby Aunt Lydia's Cove. The 1987 inlet has steadily become more difficult to navigate over the past few years, with some fishing boats relocated during the winter months to Stage Harbor and Saquatucket Harbor in Harwich. The situation was exacerbated on April 1 when a new inlet formed in South Beach adjacent to the earlier break. That created a passage from Nantucket Sound through the Southway for the first time in more than 20 years.
If more water begins to flow out the 2007 inlet, it will mean less pressure and more shoaling in the 1987 inlet, which is already showing extensive buildup of sand along the inner shoreline of North Beach Island, which is visible from Lighthouse Beach even at high tide. Keon and others who keep a close watch on Chatham's dynamic shoreline have expected the changing in inlet dominance, but it's taken longer than anticipated.
Keon pointed out that the area that broke through over the weekend was “very, very skinny” and had washed over in previous storms; he was surprised that the lobe at the northern tip of the island held on for the past few years. Just as sand building up at the southern tip of the island forced the deep channel against South Beach and set the stage for the April 1 break, the southern end of North Beach has been growing and may have helped spur the latest cut by pushing the 2007 inlet channel to the south, he suggested.
There was deep water on the bay side at the location where the new cut occurred, setting up a good flow on the outgoing as well as incoming tide. Aerial photos taken Monday clearly show a delta of sand on the ocean side of the new cut, indicating a strong outgoing tide.
“It's way too early to make a prediction, but this is not surprising,” he said. “More water is going to move more sand. Whether that's an advantage to navigation will have to be seen.”
Assistant Harbormaster Jason Holm took a boat through the new cut Monday, said Harbormaster Stuart Smith, and found about three feet of water inside the inlet along with extensive shoals at either end.
“It's a fluid situation out there,” Smith said. Sand from the new cut is flowing into a section of the channel through the 2007 inlet that had been marked with buoys. “Now half of it's no good,” Smith said. Several buoys were sanded in, he added.
He plans to reassess the situation later in the week and relocate navigation buoys as needed. He said his staff was busy Tuesday repositioning buoys in the Morris Island channel. “That has moved,” he said.
More than likely the sandbar left stranded by the cut won't last long, Keon said, and coastal geologists have forecast that North Beach Island will deteriorate and break apart over the coming years.
“Over the next few weeks this is going to change and develop appreciably. We have to just wait and see how it develops,” he said.
Whether the change will have an impact on the inner shoreline likely won't be known for several months. The extensive shoaling around the inlet currently will prevent major wave action from reaching the inner shoreline, but the usual shift in weather patterns later in the year could change that.
“That's really going to be something we're going to watch come fall and winter,” Keon said.
Michael J. Reilly, whose home is just south of the Cow Yard landing, will be watching too. The new cut, he said, is “looking right at us.” Three years ago a storm took out 10 feet of beach in front of his and neighboring properties, and a restoration projects has succeeded in holding the shore in place since. He concerned, however, that changes could expose the low shoreline to northeast storms during the winter months. He's also watching a sandbar off the north side of Tern Island which has been growing and could provide some protection for the inner shore.
“I'm hoping the town will learn [from the erosion that followed the 1987 break] and think about allowing us to do something” to protect the shore, Reilly said.