$105M Sewer Plan Raises Concerns About Cahill Basin

The $11.5 million plan to route storm water flows from Cahill Park to the Milwaukee River is one part of a larger 15-year plan to protect the village for a 10-year storm, and with street ponding, a 100-year storm.

The proposal to turn the Cahill Park softball field , route: {:controller=>"articles", :action=>"show", :id=>"residents-react-to-cahill-storm-water-detention-basin"} -->into a storm water retention basin was the center of attention at a Wednesday night village meeting about the village's

Bob McBride September 21, 2012 at 12:06 PM
It was a good meeting. I think it was the first one I've been to where they did a good job of explaining the project as a whole. The presentation made it easier to understand why certain aspects of it are being done and the rationale behind the order of progression in the plan. I think it would have helped a bit if they'd had an opportunity to explain some of the more expensive and less reliable alternatives to the Cahill retention pond that would have to be put into the system in lieu of going that route. Although there did seem to be a number of people in attendance who just were unwilling to accept that they weren't going to be able to have access to the current non-regulation softball diamond and soccer practice fields, regardless.
Bob McBride September 21, 2012 at 12:19 PM
Jeff, the plan as a whole, with "street storage" included, is designed to give protection from a 100 year storm. Your subtitle kind of suggests that the project as a whole gives protection from a 10 year storm.
Jeff Rumage September 21, 2012 at 01:24 PM
Thanks Bob. I added the 100-year street storage.
StaynConnected September 21, 2012 at 03:05 PM
I see a major flaw with the plan that the Village is considering. It favors lining sanitary sewer laterals rather than the installation of sump pumps. I am firmly convinced that the majority of the infiltration of water into the sanitary sewers under significant rain fall events is caused by foundation drains that overflow into the sanitary sewers. Lining the sewers won't address this problem. The Village is proposing to spend millions of dollars on the wrong fix (IMHO).
Bob McBride September 21, 2012 at 03:57 PM
I think that's why they're not embarking on a village wide program to line/replace laterals. Rather, they're running a test of that in Sanitary Basin 1203 first. The cost for lining/replacement is borne by the property owner. I believe Trustee Roemer stated that the alternative, to have every household in the village disconnect their floor drain and install sump pumps would cost the homeowners approximately $5K and that the Village wasn't ready to impose that on homeowners yet. They intend, I believe, to examine the results of the lining/replacement of laterals to see what, if any, difference it makes and if it's negligible, attempt to go forward with floor drain/sump pump option.
MrPierre September 21, 2012 at 05:27 PM
The village has told us (living in 1203) that we can expect to pay between $3000-$6000 for the lateral lninig or replacement. I sure hope they don't come back in five years and tell us we have to pay another $5000 to have sump pumps put in.
Gordon E Lang September 21, 2012 at 05:57 PM
Listen to Whitefish Bay Engineer Dan Naze discuss the Cahil Basin and Sewer Plan. https://www.youtube.com/watch?v=GqwjncTc2YE&feature=plcp
Chris Hayes September 22, 2012 at 12:48 PM
Lateral Line - I live in the 1203 basin and of course I'm part of the $3000-$6000 science project. If lining/repair does not make a difference then the village plan is to make us install sump pumps. How is this fair to all living in 1203? Village needs to rethink this BAD plan, Time to move?
Bob McBride September 22, 2012 at 12:58 PM
Maybe it is time to move. That's something I've certainly considered. Not so much because of this project in particular, though.. Anyways, I seem to remember at one time hearing (and this may be addressed in Naze's discussion that Gordon has linked to above) that, regardless, we're eventually all going to have our laterals inspected and either lined or replaced. MMSD has put very tight restrictions on the amount of fresh water they're going to allow to infiltrate the sanitary sewer discharge we send downline to them. The sanitary sewer lateral project is the minimum we'll have to do. If it turns out that the amount of infiltration corrected in 1203 isn't of a degree consistent with meeting those limitations, they will then push for the disconnection of floor drains and installation of sump pumps (some folks have already gone ahead and done this on their own). So while you're, in a way, part of a "science project", everyone eventually will have to have their laterals dealt with. Some folks have already done this on their own as well. That's my understanding of it.
Bob McBride September 22, 2012 at 01:19 PM
Here's some other stuff to think about: 1) The cost of this project is being based on the current cost of money (i.e., borrowing interest rates), which is extremely low as, no doubt, everyone knows. This is a project with a 15 year lifespan with yearly re-evaluations and financing done incrementally. A fair assumption is that, over that 15 year span, interest rates are going to rise, effectively increasing the cost beyond current estimates. 2) In those areas where groundwater flooding is an issue (as opposed to basement flooding based primarily on sanitary sewer floor drain backup), anything that tightens up infiltration into the sanitary system (lateral lining/replacement - floor drain disconnection/installation of sump pumps) is going to effectively increase the amount of ground water flooding to the area. For whatever period of time elapses between actions to address the infiltration issues and actions to address storm sewer issues, those areas are actually going to be more vulnerable to storm water related flooding than they are currently - although by what degree is not possible to determine. When I asked what that period of time may be for those types of areas, I was told it could be 7-10 years.
MrPierre September 27, 2012 at 05:13 PM
I still see hundreds of downspouts connected to the sewer system, when will these people be required to disconnect these rainwater sources?


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