A former longtime employee of the Detroit Water and Sewerage Department believes a combination of failure to reinforce some pipes, faulty connections into them, and a lack of frequent-enough inspections are to blame for the massive sinkhole that led to the evacuation of 22 homes in Fraser, Michigan, on Christmas Eve.

“I don’t think it’s any one person. It’s a systemic problem with communities that fail to perform inspections like they should,” James Heath told the Detroit Free Press. Heath spent nearly 40 years with the department, retiring as assistant director of water operations in 2002.

The 100-foot-wide, 250-foot-long sinkhole was discovered early in the morning Dec. 24. The suspected cause? A compromised 11-foot-diameter sewer main buried 60 feet deep known as the 15 Mile Interceptor. Bypass pumping is in place to handle flow while repairs are made, which is expected to take months. Most of the residents who were evacuated were expected to be able to return to their homes today, but three homes are officially deemed condemned.

Another sinkhole developed nearby in 2004, and the site of that sinkhole was the same location the pipe had collapsed in 1978, about six years after its initial construction. Another line tying into the 15 Mile Interceptor — the Edison Corridor Interceptor — also developed problems around that time.

“Inspection and maintenance should be a continuous process,” Heath told the Detroit Free Press. “I think there was a lax period where the inspection was not being done as often as it should.”

He questions why the most recent inspection of the area of pipe that collapsed was in 2009, especially considering its proximity to the site of the 2004 sinkhole.

“I would say somebody was falling asleep. Out of sight, out of mind — that’s the mentality of too many bureaucratic people running systems,” says Heath.

He also notes that the area of the sinkhole has sandier soils, and that many of the pipes were not reinforced with steel bar but probably should be.

Source: Detroit Free Press