Portions of metro Milwaukee got as much as six inches of rain from Sunday through Wednesday morning, according to the Milwaukee Metropolitan Sewerage District.
The city’s Department of Public Works says some streets were flooded because storm sewers backed up due to the heavy rainfall, and the debris that blocked some sewer drains.
DPW Marketing and Communications Officer Tiffany Shepherd told WUWM’s Teran Powell that even if sewer grates had been completely clear, the volume of water alone could have overwhelmed the system.
Shepherd says the DPW got about about 1,000 calls for service related to flooding.
This conversation has been edited for length and clarity.
Clean drains help after storms, but cannot prevent flash flooding
Tiffany Shepherd: People have questions about drains being like plugged up and what might be the cause of the flooding, but honestly, there's a flash flood warning so we were already sort of aware that the potential for that could happen and that potential was because of the weather conditions. Nothing to do with the drains per se, or the system, just the conditions that existed were going to be that extreme.
We always promote cleaning out drains. In a normal rain, if you see flooding, it could very well be because that drain was plugged. This kind of heavy rain — our storm systems are in perfect working condition, but no system is really is built to handle that amount of water in a short amount of time. If that same amount of water had [fallen over] a longer time where the system could handle it better — but that much water that quickly it just overwhelmed the system.
We even saw some manhole covers popping as a result, because the system just got full.
Again, we always encourage people to clean out drains, 'cause yes, once the rain stops and the water starts to recede we want it to be able to dissipate as quickly as possible. Clean drains help that, but clean drains are not going to prevent the kind of flooding we saw. It can't stop flash flooding. That's why you'll notice it's not just in Milwaukee, but we have these issues all over the area. It's just really because of the conditions.
Ahead of the initial rain that we saw on Tuesday, our crews even went to two known areas that are known for flooding and make sure that drains and everything were clear, but that still didn't prevent the flooding from happening.
Even when drains are clear, sometimes what can happen is when the rain starts, any debris or anything that's in the street, it still pushes it to the drain, even if the drain was originally clear. Our crews ahead of springtime do go out and clean drains.
If some of public sees that their drain is clogged, that they can safely just remove that debris themselves, that's amazing.
Obviously, if it's flooded and you don't feel safe, you call us, we'll always respond. And that's sort of just in normal rain events, but again, what we saw was not a normal rain event, that was exceptional and unfortunately [even] with clean drains, couldn't prevent that kind of flash flooding.
Teran Powell: What does cleaning the water, the drains look like?
That's our sewers team and they have hand crews who come and do it. They also have like vacs that help with that. And again, they do that on a normal basis. They also did that on this basis, so that once the intensity of the rain stopped, to help facilitate that better drainage, but ultimately it just took time and for the intensity of the rain to slow down for the water to be able to drain appropriately and clear up that flooding.
Are you able to say where most of the calls for drains, or where most of the flooding has impacted in parts of the city?
I don't have the data in front of me specifically, but we know that there was heavier rain on the north part of the city. It just experienced more rain so therefore more flooding.
