More golf course sinkholes? What are the chances?

Michael Mihal in sinkhole
STLToday.com
Michael Mihal was rescued from a hidden sinkhole in a fairway at Annbriar Golf Course in Waterloo, Ill.
PGA.com

Series: Golf Buzz

Most of the golfers I know wanted to put the thought of getting swallowed up by a sinkhole out of their minds as quickly as possible after that guy in Illinois plunged into an 18-foot deep sinkhole in the middle of a fairway a few weeks ago.

Being a curious reporter, Jennifer Welsh of The Business Insider wanted to know more, not less, about the odds of dropping through the ground on a golf course. Specifically, she wondered whether golf course landscaping techniques might increase those chances.

She asked David Weary, a geologist at the U.S. Geological Survey who specializes in karst terrain – sinkhole-susceptible areas made up of soft rocks like limestone, gypsum or salt beds that can be washed out by water.

''In my opinion it is possible for irrigation and landscaping to affect the risk of sinkhole development on golf courses over karst areas,'' he told her in an email. However, he noted, 'Golf courses are usually graded to avoid standing water, so the chances of this should be pretty low.''

Normal irrigation ''would probably not put enough water on the surface to cause sinkholes directly,'' he wrote. 'It is possible that over-irrigation over time could cause some movement of sediment in the subsurface (through caves) and result in eventual localized sinkhole development. Also, if landscaping resulted in a spot where the surface drainage ponds it's possible that the combination of heavy standing water and enhanced drainage of that water to the subsurface could move sediment and initiate a collapse.

The most likely causes of collapse sinkholes in areas like golf courses 'are leaking irrigation pipes or leaking stormwater handling structures like drain pipes and retention ponds,'' he added. ''Chronic water leaks can, over time, erode the subsurface soils and cave fills leading to creation of void spaces and subsequent collapse of the surface into them.

''We don't have enough site-specific information about the Illinois golf course sinkhole to comment as to whether it is purely natural, or man-induced.''

So there. Don't worry about falling through a sinkhole in the fairway of your favorite course. But watch where you step!

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