CHATHAM — The Barnstable County dredge Sand Shifter is living up to its name as it works to clear the Stage Harbor entrance channel, nourishing eroded south-side beaches at the same time.
The dredge began operation on Feb. 3, but adjustments had to be made to the newly rebuilt booster pump, which is stationed on Harding's Beach. The booster relays the sand-and-water slurry churned up by the dredge to another pipe leading to a beach just west of Cockle Cove Beach, where it is deposited. Over the summer, the new sand will migrate to the east, nourishing several erosion-prone public beaches. The booster pump was properly adjusted and dredging began in earnest on Feb. 10.
“So far, so good,” Chatham Coastal Resources Director Ted Keon said this week. The dredge is successfully clearing the inside portion of the channel before moving outside the harbor. There, conditions will become more challenging.
“The currents that we were concerned about haven’t yet posed a significant issue. Hopefully that will stay,” he said. The Sand Shifter was unable to work early this week because of gusty winds from the south and southwest, which make the seas too choppy.
“When conditions are good, the production seems to be pretty good,” Keon said. The dredge is moving more than 800 cubic yards of sand each day toward its target of between 20,000 and 30,000 cubic yards. It is the largest dredge project of its type since the early 2000s, and required some special preparations.
Moving sand to a beach nearly two miles away has always been a challenge, requiring long lengths of pipe and a booster pump. The pumps sometimes fail, and the pipe is often in use at other dredge projects around the Cape. To solve the problem, the town purchased 3,000 feet of its own pipe, which was assembled at Harding's Beach into 10 300-foot long pieces. Because annual dredging is required to keep the Stage Harbor channel navigable, the town will get regular use of the new pipes.
While dredging operations in the fall must finish in time to avoid interfering with rules that protect young winter flounder, the only environmental deadline facing this job is the arrival of nesting piping plovers, which becomes a concern after April 1. Barring unexpected problems, the dredging of Stage Harbor will be complete long before that time – perhaps as early as a week or two from now.
The area outside the harbor receives sand from the west, but is also subject to shoaling from currents passing through the barrier beach inlet to the east. In recent years, the sand has accumulated quickly, filling the navigation channel and immobilizing navigational buoys. The goal of the Sand Shifter is to make progress on the large shoal that is blocking the outer channel, not to get the harbor entrance fully cleared for the start of the summer boating season, Keon said.
“There’s plenty of sand to be moved,” he said. “We were fully anticipating that this, by itself, would not offer us I think the comfort level that we would want for the channel going into the season.” The town has asked the U.S. Army Corps of Engineers to make one of its dredges available to complete the job sometime in the late spring or early summer, and Keon said the Corps has the available funds to do so. Stage Harbor is a federally-maintained harbor.
The federal dredge won’t be the Currituck, the Corps’ hopper dredge that routinely visits Chatham, since that vessel is in drydock for maintenance. A newer version of the ship, the Murden, will likely be the one coming to local waters. Both vessels are of similar size and have similar capabilities, Keon said.
When it completes its work at Stage Harbor, the Sand Shifter won’t be leaving town. Its next assignment is to clear the mooring basin in Aunt Lydia’s Cove, west of Tern Island. Though it will not require the booster pump, the job will involve pumping sand ashore to nourish a beach, Keon said. As was done once before, the recovered sand will be moved to the private beach at Linnell Lane, which is severely eroded, Keon said. Previously, property owners in that neighborhood contributed funds for the beach nourishment; this time, they are providing the public with a “strolling easement” that allows people to walk across the private beach.