'No sea monsters, no runaway tug' boat led to Hutchinson Island sinkhole, but cause still unknown

The damage sustained this weekend on Hutchinson Island was not caused by a runaway tugboat, a rogue ferry or a "sea monster," but the cause — and total cost — of the sinkhole has yet to be uncovered.

Chatham County officials gave media an update on the sunken sidewalk and dock landing Thursday, five days after the first signs of shifting soil were uncovered on the island across from River Street.

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"The early assessment is that it's multiple contributing factors (and) it's contained to the area that you can see just outside of the building here at the Convention Center," said Chatham County Manager Lee Smith.

While city officials first blamed the weekend's 3.9-magnitude earthquake for the damage, Smith said no one cause can be ruled out or blamed completely. In all likelihood, he said, the damage was caused by a "confluence of events" that could include the earthquake, settling soil and nearby construction.

"No sea monsters, no runaway tug... CAT ferries didn't run into the wall. Nothing like that," Smith said. "As far as the issue with the earthquake, you can't say it has or has not. But if you looked at the type of earthquake, it was fairly concentrated."

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The county has pulled in several local contractors to assess the issues and is currently conducting ground-penetrating radar to find out the depth and scope of the damage.

The area is blocked off with fencing and caution tape, but activity on the island will not cease, Smith said. The ferry is picking up and dropping off in front of the convention center (which will host the Georgia Municipal Association Annual Conference beginning Friday) and Westin operations have not been impacted.

The $271million convention center expansion project is still under construction, as well. It was not impacted, according to Joe Marinelli, president of Visit Savannah.

"It's basically a construction site," Smith said. "So, just like you would in the front (convention center construction), do not interfere with operations and construction and assessments."

The City of Savannah was the first agency to jump on the issue last weekend. Smith said the county is grateful to the city for getting ahead of the issue, and ordering sheet piles to protect pedestrians and workers, but the county was taking the lead from here on out.

According to an email sent to Smith from City Manager Jay Melder, the county declined to address the issue until Tuesday, June 21.

"We started bringing people in, they've been on site, looking at all these things since Saturday," Smith said. "... somebody's been here every day. And what we wanted to make sure is that I can have all of our partners in the room hearing the same thing, because our messages going out, will come through the county."

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Smith said the county pulled together all stakeholders on the project Thursday morning and it's believed the damage sustained near the dock has been a growing issue for longer than previously suspected.

Major construction is happening on all sides of the damaged walkway, including extensive work to drive pilons into the ground to support the weight of a new apartment building, and the 200,000-square-foot convention center expansion. Smith said they are looking into whether the construction caused this damage, but said the ongoing activity is not at-risk.

"Where you have buildings is different than construction right on the river, because it's a whole different system," Smith said, noting the soil and method of building is different, too. "When you put sea walls up or retaining walls, they take a major beating. So again, all these things we've got to take a look at."

Smith did not give a timeline or cost estimate, since damage assessment is still in the early stages.

"It's safe, operations are not changing, and we feel really good about that."

Zoe covers growth and how it impacts communities in the Savannah area. Find her at znicholson@gannett.com, @zoenicholson_ on Twitter, and @zoenicholsonreporter on Instagram. 

This article originally appeared on Savannah Morning News: Hutchinson Island GA sinkhole cause unknown, operations still a-go