Milwaukee Mile gets caution flag over erosion

A race is on – 15 feet beneath the Milwaukee Mile track – to prevent the collapse of leaking metal pipes carrying the entire flow of Honey Creek under State Fair Park in West Allis.

Should the pipes fail, sinkholes could form on the infield of the historic oval and swallow a section of a road course used by sports car clubs, officials said.

Though a NASCAR race is not scheduled this year at the Milwaukee Mile, the track and road course will be open to car clubs and driving schools.

The ground surface already has subsided 2 feet at three spots adjacent to the infield course, said facility engineer Jeff Jacobson. The pipes are not much deeper, just 15 feet or so below ground.

Fair Park crews have dumped gravel on the depressions, first observed in the summer of 2008, as they monitor the stability of the soil, Jacobson said. The area is fenced off from parking during the annual State Fair.

The Milwaukee Metropolitan Sewerage District's commission on Monday will discuss hiring a contractor to line the bottom of each of four metal pipes with concrete to stop leaks and prevent further corrosion of bolts holding the pipes together. During construction in late 1964 and early 1965, corrugated steel plates were bolted together to form 9-foot by 13-foot oval culverts.

Water from the creek has been leaking out cracks in the bottoms of the aging pipes, eroding soil around them, said David Fowler, MMSD senior project manager.

Soil above the pipes drops down, filling voids but causing depressions on the surface, he said. More at JSonline.com