Flash Flood of 2018: A Look Back, A Look Ahead


DISPATCH: There’s about five cars literally up to the roof. Nothing we can do. June 30th, 2018 brought a torrential downpour and in many neighborhoods particularly in the north side of town It was a record-setting amount of rainfall in a very short period of time and it absolutely overwhelmed the ability of the storm sewer system to handle that kind of rain. Something happened in Des Moines that had never happened before. We’re a pretty strong, great, resilient community But on June 30th the climate won, And we had to figure out a way to get around it. We’ve designed storm sewers to handle once-in-a-lifetime kind of events and this was once in three lifetimes. That is not something that any infrastructure is ever designed for. We ended up with over 1,800 homes that reported negative impacts from the flood. Whether it was minor basement flooding to just outright destruction of the structure, The City offered to purchase just short of 100 homes in the immediate weeks right after the event. Being able to do that with local dollars meant we could do that while the basement had not yet been repaired the basement walls were still open and unsecured and before any of the mechanicals had been repaired or replaced and step in to offer financial assistance to move those families onto new homes elsewhere. So all around the city, there were lines of people trying to get rid of damaged property; couches fridges, you know, carpet drywall. And it was astounding the amount of garbage and ruined materials that this flood created. Luckily the water dissipated quickly, but it was really obvious the pattern of problems that the city had. Issues that we could solve that we had never seen before because we had never seen a night like that. The stormwater experience in those neighborhoods is very different now than it was when those neighborhoods were built in the 1930s, 40s or 50s. The flood response has showed us exactly where we have problems in our storm sewer system. The ability to move homes out of kind of that escape path for the extremely large quantities of water has been very helpful. In this aftermath of the flood experience, the City Council asked the City staff to to be able to plan to do this even faster. We need bigger sewers we need to tear up our streets we need to spend the money that’s necessary. And we used to fight over petty things: “Can we use your land?” “Can we buy this property from you so we can put the sewer through this area?” It’s all for one and one for all now that this is a problem we’re going to solve. We’re actually looking at spending over $145 million over the next six years on stormwater improvements alone. Just to give a comparison the City spent $80 million in the past 10 years. So, pretty much tripling the rate of projects focusing on stormwater in the city. So what was already a a historic increase in the pace of construction of storm sewer improvements by the beginning of 2018 turned into, in the middle of 2018, an even faster, accelerated pace of construction of those improvements. We’re continuing forward with the plan to improve what’s called the Closes Creek Watershed which is primarily in the Beaverdale neighborhood work recently started on Maquoketa Drive which involves installing a large sewer box We’re also starting on installing some large sewer boxes in the area of 47th and Holcomb which will for one, provide conveyance, but also actually store water underground to slow the release of stormwater that makes it way through the system. A perennial question we get from property owners in and around the city is what can they do to help? And it is always hard to think about building big storm sewers. They’re big, large, expensive infrastructure that’s publicly owned. It’s in the street, it’s not on your property. But every single property in town has rainfall that lands on it. And there is always an opportunity to capture and infiltrate some of that water on one’s own property before it reaches the storm sewer. A great example is Soil Quality Restoration where you simply add extra organic matter to the existing turf. It stays exactly the same but it turns the yard into more of a sponge so it can capture and hold rainwater that lands on it and releases it back to the environment at a much slower rate so it doesn’t become contributory flood water to your neighbors downstream.

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