East Lansing's water system
For the most part all of our wastewater flows almost to the Red Cedar River and there's a large interceptor that collects everything and diverts it to the wastewater treatment plant on the far west side of the city. But during wet weather flow in the past the city had 14 separate points that overflowed directly into the Red Cedar River when the sewer reached capacity. During 1993-5 the city built a large tunnel sewer under the ground- on this map the pink line- that flows along Michigan Avenue and Grand River Avenue all the way to Bogue Street. so that when there are large flows the main lines run into this tunnel so that when there are large flows instead of getting down to the river area they all dump into this tunnel. When it gets to the end of this tunnel it can be pumped to our wastewater treatment plant. So now there is only one place where there is overflow directly into the river that has primary treatment and overflows only one, maybe two times a year...
One of the things with a combined sewer is trying to not just upsize the existing infrastructure that's in the ground, but are there some other ideas we can use......As part of the (MS4) stormwater permit one of the things we'll be needing to do is some green infrastructure projects...
-Todd Sneathen, Director, East Lansing Department of Public Works
excerpt from 12.11.13 presentation