First large Westlake sinkhole
Over Memorial Day weekend, a sinkhole measuring 25 feet in width, 50 feet in length and 25 feet in depth opened up on 30532 Detroit Road, adjacent to Fifth Third Bank’s parking lot in Westlake. Days later, a smaller second sinkhole appeared near the first one.
These two sinkholes were caused by a collapsed storm sewer pipe, according to Westlake Chief Engineer Robert Kelly. In all, 300 feet of storm sewer pipe needed to be replaced. It will cost the city $183,278.67. Kelly said that this particular segment of pipe had served “its useful life.” Made of metal corrugated pipes, popular in the '70s, it was retrofitted when the Savannah development was put in.
The old pipe accounted for about 5% of Westlake’s storm sewer lines, Kelly estimated. “We know where they are at … [the] vast majority.” This is the first-reported sinkhole in Westlake.
In a 2015 Cleveland.com article, Solon, which tracked sinkholes that ”average in size from as small as a coffee can to as large as a five-gallon bucket” reported approximately 100 sinkholes a year. John Busch, Solon’s city engineer, said he could not verify the total number of sinkholes currently, but they’re typically caused by leaking joints in older storm sewers. Their largest sinkhole was from a water main break.
Manmade sinkholes like the ones in Westlake and Solon are different from natural sinkholes, a result of natural soil composition and water runoffs. The at-risk area is called a karst.
Douglas Aden, mapping geologist from the Ohio Department of Natural Resources, said, “Most sinkholes around [Northeast] Ohio are manmade. Common causes of [manmade] sinkholes include collapsed sewers, leaking water pipes, broken field tile, old cisterns and wells, buried rotting wood like construction materials and stumps, and in Eastern Ohio – abandoned underground mines.
“There are currently 6,999 field verified [natural] sinkholes in Ohio. This number is steadily increasing as we map the state in further detail. … All told that’s a total of 15,566 known or suspected sinkholes in Ohio which includes about 200 caves. In addition, there are 474 springs related to karst across Ohio.”
The Bellevue-Castalia Karst Plain, which straddles Seneca, Huron, Sandusky and Erie Counties, is the closest to Northeast Ohio. It has the largest number of sinkholes in Ohio with depressions up to 270 acres in size.
For more information on Ohio karst, visit geosurvey.ohiodnr.gov/geologic-hazards/karst-geology/karst-mapping.
The final repair to the Westlake sinkhole will be completed in the fall.