When a sinkhole four feet deep and 15 feet long opened up under a pathway in Port Royal Plantation onMonday, town engineers rushed to fill the cavity.
Workers dug up the pathway to examine the 30-year-old pipe that caused the problem.
What they found was not surprising.
"The pipe is so deteriorated it's like Swiss cheese," said Bill Dobbing, a Cleland Site Prep worker. "As these pipes get older and older, more of these (sinkholes) are going to happen," he said.
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Failing pipes have been an increasingly costly problem for the Town of Hilton Head Island since it began taking over aging drainage systems from gated communities about five years ago.
The town expects to spend $25 million over the next 10 years fixing and replacing aging pipes, said town public projects director Scott Liggett.
The town already maintains the drainage systems in Sea Pines, Shipyard, Hilton Head and Port Royal plantations, and will take over some facilities in Indigo Run and Palmetto Hall this year, Liggett said.
The crushing cost of fixing pipe failures has been siphoning away about 60 percent of the town's funding for drainage improvements each year, Liggett said.
At least 300 feet of pipe must be replaced under the Port Royal pathway on Grasslawn Avenue that failed this week -- a project that could easily cost $250,000, town stormwater administrator Cary Gaffney said.
It's the fourth major sinkhole this year, he said. The others were in Hilton Head Plantation, one in the winter and two this spring.
The town pays for the improvements through an annual stormwater fee levied on residents.
The fees will generate about $1.67 million in the next year, according to the town's budget. But that figure assumes the Town Council will raise the average fee from about $83 a year to $108 a year, Liggett said. It raised the fee last year from about $53 to its current level, he said.
The rate increase would cover basic maintenance costs and one major project in each of the gated communities a year, Gaffney said.
But that budget has no "cushion" to address emergency repairs like the one Monday, he said, adding that a rate of $108 "is the absolute bare minimum we can squeak by with," he said.
But even that fee increase will not cover what the town has already spent on emergency repairs, Gaffney said.
Town manager Steve Riley wrote in a memo to Town Council members Tuesday that the town has been overspending its stormwater maintenance budget for several years, using hundreds of thousands of dollars from other accounts to cover the deficit.
The town hopes to issue a bond of $5 million to $7 million this year to repay money it shifted from other funds to pay for the repairs, Gaffney said.
The bond also could help fund studies that would send video cameras into the pipes, allowing town engineers to predict potential problems instead of waiting until they arise, he said.
Earlier this year, some Town Council members expressed reservations about the fee increase. But Mayor Tom Peeples urged them to pass it.
"This is the one way we can get 70 percent of the island a benefit for their tax dollars," he said. "We can't just take on responsibilities and then act surprised when we have to fund them."