Sewer repair plan would prevent some backups

Wauwatosa public works staff expects that the plans to repair the sanitary sewer system in the Ruby Avenue neighborhood would prevent flooding in basements as a result of sewer backups if rain falls at the rate seen during the June storms of 2008 and 2009.

But whether the designed pipe size and pitch could handle the amount of water that fell on the area during floods that occurred in 1997 and 1998 remains up in the air.

Consultants are studying the scenarios before taking the project to the Common Council for approval to complete the design and submit plans to Milwaukee Metropolitan Sewerage District for its approval. Construction could start this summer.

There is a caveat to the expectation of eliminating basement backups, City Engineer Bill Wehrley said. The MMSD's system has to be functioning without any excessive backups that could cause problems down the line.

And there was a "fluke" incident a few years ago when sewage in MMSD's pipes backed up 12 feet, but it didn't occur after a large rainfall. In those unexplained cases, extra precautions, like installing sump pumps and disconnecting foundation drains, would be needed to prevent backups.

The city could build a pump station to handle these rare incidents, but at an anticipated price tag of $500,000, that goes above the level of protection city staff want to provide, Wehrley said.

The Ruby Avenue area is just one part of the city that has experienced flooding.