Flood-prone communities face a unique set of challenges when it comes to preparedness and resiliency especially when faced with an ever changing climate.
To ensure long-term viability, it is imperative that these communities consider flood resiliency and preparedness as an essential part of doing business, rather than reacting during a flood or cleaning up after a flood. The long-term success of any resilient community will depend on its ability to research, plan, implement, involve stakeholders and fund their flood risk mitigation projects.
The community of LaCrosse, Wisconsin used the knowledge it gained after a flood event to capture important data that will help the city in future flood events.
While floods can devastate communities, there can be an upside when it comes to capturing data and analytics to minimize impacts of future flood events. Cities can actually stand to benefit when there is a flood or big rain event. It gives them the opportunity to get more accurate data, improving the flood mapping and modeling used to help prepare for major flood events. The improved modeling can have the potential to unlock financial savings for its residents as well, making it a smart approach for those communities looking to use data and analytics to their advantage.
After an intense storm and flooding in July 2017, the City of La Crosse, WIsconsin, evaluated whether the flood hazard was appropriately identified for the residents. To get the answer they needed, they required more accurate data. Floodway mapping and modeling provided them with answers.
The flood potential risks shown on a floodplain map should reflect that of the real world. Estimating, real world data from flood events provides us with a more accurate picture of whose impacted in a floodplain and how to plan for the future.
More accurate data can save the City and homeowners money. Previous models may have misidentified homes as being located in a floodplain. This would potentially cause the homeowners to pay for flood insurance they might not need. Or, if flood insurance is needed it would result in higher premiums than necessary.
La Crosse is taking the opportunity to capture the correct data on its floodplain by distributing surveys to landowners in a 1.13 square-mile region near the floodplain. This survey data coupled with modeling helps paint a more accurate picture.
Woznak says that any available data can help.
“Past modeling over-predicted the flood runoff, and roughly 88 homes should have been inundated because of that flood event," he says. "But, the survey data told us something different."
Now, the City is using this new set of data to better inform residents.
Ultimately, La Crosse and its residents may save on purchasing additional flood insurance.
More info on how SEH and La Crosse have partnered together on flood data can be found here.
The best way to protect your city against flood events is to have a plan. But all cities are different and those plans can vary a lot between cities. Over time, it's important to update your city's plan on the data you've gathered. If you don't have a plan, make one. There are some easy tips to get started on a plan right away. No plan has to be perfect right away—it can be something that evolves along the way.
Brad Woznak, PE, CFM is a Project Manager and Lead Hydraulic Engineer at SEH. Brad has helped clients prepare for more resilient futures through hydraulic and hydrologic analysis, watershed modeling and floodplain analyses. Please contact SEH project manager Brad Woznak to discuss your flood risk management projects. Contact Brad