Clam Pass undergoes major dredging in North Naples for second time in three years

For the second time in three years, Collier County has had to dredge Clam Pass, this time at a cost of $236,332.

Pelican Bay Services Division, an arm of county government, oversaw the dredging project, which was paid for by the county's tourist tax on hotel stays. Neil Dorrill, division director, said the dredging was a result of Hurricane Irma.

"Prevailing wind from Irma pushed all of the sand that had been at the beach into the inlet, which caused critical erosion at the beach and threatened to close the pass,” he said.

To fix it, engineers had to pump approximately 8,257 cubic yards of sand from the inlet back on the beach. The project finished earlier this month.

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Clam Pass is especially vulnerable to closures from waves and winds because it is a small inlet that does not have jetties to help keep it open, Dorrill said.

Unlike other small natural inlets in undeveloped parts of the Ten Thousand Islands, for example, Clam Pass is unable to move to stay open when it is threatened with closure.

“Clam Pass is one of, if not the smallest natural inlet on the west coast of Florida, so it’s very impacted by wave energy,” he said. “When the seas and storms are mild, the pass can go a long time, but when we have significant tropical storms, hurricanes or cold fronts like we’ve had in the last four years, the frequency of maintenance is there.”

Further complicating the issue is the fact that Clam Pass is a haven for migratory birds and other wildlife, which makes it difficult for the county to make any modifications to the inlet, even ones that would help prevent it from closing.

“Other inlets in Naples like Doctors Pass, Gordon Pass or Caxambas Pass (on Marco Island) have large revetment structures made out of boulders, pilings or other materials," Dorrill said, “but because of the environmental sensitivity at Clam Pass, it would be difficult, if not impossible, to get permits to create some sort of artificial support for the pass.”

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Clam Pass last filled with sand in 2013, just weeks after crews had reopened the pass after it closed in late 2012. Since then, the pass has undergone emergency repairs almost annually.

Due to the frequency of the repairs, Collier County obtained a 10-year permit from the U.S. Army Corps of Engineers that allows maintenance work at the inlet. Last year's repair cost $112,000.

The pass splits Clam Pass Park and Pelican Bay's South Beach before flowing into a 209-acre preserve filled with mangroves and tidal flats. Tidal flow in and out of the pass is critical for maintaining the saltwater-freshwater balance and the health of the mangroves.

The last major dredging project took place in 2016 after heavy winter rains and poor tidal flushing at the mouth of the choked pass flooded patches of mangroves, causing an 8-acre die-off.

The project cost more than $400,000, and officials had hoped it would keep the pass open for five years, but then Hurricane Irma hit Southwest Florida.

"On average we would hope that the inlet would only need to be dredged every four years," Dorrill said, "but again, it's entirely dependent on wave energy and weather events like Irma."

Dorrill said the contractor finished the project a week early, and he couldn't be happier with the work.

“Within hours of finishing there was a pair of manatees and dolphins in the back bay," he said. "It was a nice end to what had really been a very good project."