JANESVILLE — Phrases such as “hydrostatic pressure,” “seepage” and “Army Corps of Engineers” usually mean trouble.
Not in this case.
City officials Friday called in the Army Corps of Engineers, Department of Natural Resources dam specialists, and a private consultant to confirm what they already knew: the Centerway Dam’s structure is sound, despite rising river levels and tremendous pressure on bridges, dams and river walls.
Steps are being taken to relieve the strain on the sodden earth around the dam.
Engineers and public works employees have been monitoring areas near dams at regular intervals, said Jack Messer, the city’s director of public works. On Friday, they noticed that the area north of the Centerway Dam, on the east side of the river near Adams Roofing, was showing signs of seepage.
Seepage is what happens when floodwater soaks into the earth. Water begins to bubble up through the ground, as though as artesian well has come to life.
When a large section of ground becomes saturated, water begins to move through the ground, seeking the path of least resistance. There’s that hydrostatic pressure.
Water traveling through the earth can carve a new path around major obstructions—such as a dam.
Seepages coming up from sodden earth are called “boils.” Engineers used sandbags and other materials to relieve pressure at the site.
The river was expected to crest late Friday or early this morning.