Palatine sinkhole fix will take a while longer

The two-week time frame officials provided when estimating how long it would take to close the massive sinkhole that formed on Palatine’s north side after a 100-year storm hit the area has come and gone.

Fixing the 15-by-20-foot opening at the northwest corner of Hicks and Dundee roads quickly proved complex because of the utilities involved, as well as the discovery of buried bracing material from when the sewer line was originally built, Public Works Director Matt Barry said.

The sinkhole formed July 23 about 30 feet below the surface when a sewer line collapsed in the wake of a torrential downpour — 5.43 inches of rain in three hours.

Barry said he went to the scene Monday and found crews still in the excavating phase, so it’s premature to say how much longer repair work will take.

It’s also too early to determine the total cost of the project, according to Patricia Young of the Metropolitan Water Reclamation District of Greater Chicago. The water agency reached an emergency contract with Burr Ridge-based Sheridan Plumbing and Sewer to do the work.

Village Manager Reid Ottesen said that whatever the amount, Palatine isn’t on the hook for anything. However, officials estimate the storm will cost the village about $100,000 in other cleanup and overtime expenses unrelated to the sinkhole.

After another storm passed through Monday afternoon, yet again leaving hundreds of Palatine residents without power and prone to flooding, a frustrated Councilman Aaron Del Mar asked Ottesen to invite a ComEd representative to an upcoming council meeting to address concerns at a public meeting. That likely wouldn’t take place until October, Ottesen said.

Sinkhole causes

Broken and collapsed water mains and sewer lines may be the most common culprits behind sinkholes, but there are plenty of others.

Regions with ample limestone, such as Illinois, are prone to sinkholes, as the rock dissolves easily. Sinkholes can be thousands of years in the making, as water dissolves minerals, forming voids whose surface may collapse for reasons including:

Ÿ Decline of water levels or change in groundwater gradients

Ÿ Soil disturbance through digging, soil removal or drilling

Ÿ Heavy loads on the surface

Ÿ Creation of dams, reservoirs or ponds

Ÿ Vibration

Ÿ Overpumping of groundwater

Ÿ Freezing and thawing, and big changes in precipitation

Source: Pennsylvania Department of Environmental Protection, Geohazards Inc.