Sinkhole Dangers Lurk When Underground Infrastructure Fails

ROGER SCHNEIDER
Associated Press

DETROIT (AP) — Massive sinkholes in Michigan and Pennsylvania in recent weeks underscore an often overlooked aspect of the nation's aging infrastructure lurking underground.

Sinkholes in streets in Fraser, Michigan, and Bethlehem and Philadelphia, Pennsylvania, have disrupted lives, and swallowed or threatened to take houses and vehicles. Here is a look at those sinkholes and others.

THE SINKHOLES

The latest string of sinkholes started in the Detroit suburb of Fraser on Christmas Eve. Of 22 houses affected by the sinkhole, three have been condemned. Officials temporarily evacuated 19 others because water and gas service had to be shut off. About 400,000 people in nearby communities were asked to take shorter showers and wash only full loads of clothes as part of a voluntary water conservation plea until a fix is completed.

The next sinkhole occurred four days later on a street in Bethlehem, about 70 miles north of Philadelphia. About 30 residents were evacuated and a four-block area was closed to traffic. A utility worker suffered minor injuries when he fell into the hole. That city also had a massive sinkhole in September that forced the evacuation of homes in a six-block area.

Then on Sunday, a sinkhole opened up on a street in Philadelphia that swallowed two cars. Twenty homes were left without water and gas service to six residences was shut off as a precaution. Bottled water has been provided to all affected residents.

SINKHOLES AND INFRASTRUCTURE

Water main breaks caused the sinkholes in Bethlehem last month and Philadelphia. Officials still have not determined the cause of the Fraser hole. Public works officials are investigating whether a 2-inch diameter hole bored through a sewer pipe after a 1978 collapse allowed groundwater to move up into the line and erode the soil beneath the pipe, resulting in the collapse.

SINKHOLE COSTS

Repairs to just the sinkholes can run into many millions of dollars. Officials are a long way from determining and finishing repairs, for instance, to the Fraser sinkhole. That hole is larger than a 2004 sinkhole in the same area that cost $55 million to repair. Michigan Gov. Rick Snyder last week declared a state of emergency for the county where the collapse occurred. The disaster declaration makes state resources available to the county and communities affected by the sewer collapse. It also raises the possibility that state, and possibly federal funds, could be secured to pay for some of the work and costs.

Besides the possibility of losing their homes, residents who can return home face the likely loss of property value — at least in the near term — since few people want a sinkhole for a neighbor.

Another sinkhole in 2013 under a Florida house swallowed a 36-year-old man whose body never was recovered.

SINKHOLES AND THE ENVIRONMENT

Sewage was pumped into the Clinton River because of the Fraser sinkhole to prevent flooding into residential basements. City and state officials say the discharge was a last resort.

A Florida sinkhole in August caused more than 200 million gallons of tainted water to drain from a waste heap through a 45-foot-wide hole into the aquifer, which provides water to millions of people. The tainted water came from fertilizer plant waste.

PREDICTING SINKHOLES

Many sinkholes occur in Florida because of its geological makeup. The Florida Department of Environmental Protection says on its website that it is not possible to predict when or where a sinkhole will develop. It says that in some cases geological tests can assess the potential for sinkhole development, but they are costly and require experts to perform.

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