Flood-prone communities face a unique set of challenges when it comes to preparedness and resiliency.
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.
In the United States, we typically consider areas as floodplains only if they are shown on a Federal Emergency Management Agency (FEMA) map or located in low-lying areas along a river, lake or stream. Of course, the level of flood risk increases for the areas we typically identify as floodplain or which have been flooded in the past.
Unfortunately, Mother Nature doesn’t read flood maps. Every year areas are flooded that are not in mapped floodplains or have never experienced flooding in the past. In other words, all communities are at risk of flooding on some level and therefore located within a floodplain.
Even if your community is not identified on a flood map, researching and developing an understanding of your community’s flood risk or areas of the community most at risk for flooding is essential to increasing resiliency. In addition, flood research leads to defining a course of action to help flood damaged areas bounce back faster or potentially avoid being flooded altogether.
Flood damage to area businesses, residents or critical facilities can be catastrophic to your community’s future growth and economic development. When businesses or critical community facilities experience long-term flood damage, businesses can lose valuable revenue for days, weeks and months.
Many businesses may not survive or do not want to be at risk for additional future flooding and will move to a more resilient community instead of rebuilding in a flood-prone area. This can be a major economic blow to a community resulting in a loss in community identity and tax base.
This not only affects the community in the short term, but can have a chilling effect on the local economy as potential new businesses and commercial developments shy away from opening up in a flood-affected area. In addition, as floods damage residential areas, it can negatively affect the social fabric of your community by discouraging new residential and retail developments. This can erode a community’s confidence and stunt its potential for growth.
Fortunately, communities already have many tools at their disposal to increase flood resiliency. Hazard mitigation and flood planning can be incorporated into a community’s comprehensive plans by involving local government emergency response personnel, the community floodplain manager, and department of public works in the planning process.
Resilient communities — communities that are actively planning ahead — often incorporate pre-disaster mitigation measures such as acquisition of flood-prone lands, adopt No Adverse Impact floodplain regulations, and promote green infrastructure into their local Hazard Mitigation Plans.
Even if a flood does occur, resilient communities are able to bounce back faster and move toward measuring recovery time in hours of receding floodwaters, instead of measuring recovery time in days or weeks. This strategy allows communities to move toward increased flood resiliency and also positions them well for future pre-disaster and post-disaster grant applications.
Once your community has researched where flooding occurs most often and which areas of the community are most vulnerable, you can begin to implement a plan to mitigate flood risks and increase the resiliency of these affected areas.
Implementation can include a variety of strategies including:
Community-led activities such as active participation in FEMA’s National Flood Insurance Program Community Rating System can increase flood resiliency and benefit the community as a whole through a reduction in flood insurance premiums.
Resilient communities are ones that promote active involvement from area stakeholders, businesses and residents when developing, updating or implementing their flood risk mitigation strategies. It is important to involve your community early and take every opportunity to engage your businesses and residents.
Ask questions, obtain feedback and work closely with area stakeholders when developing and implementing your community’s plan. Promote an active discussion and help educate your stakeholders about the benefits of your community’s short- and long-term project solutions.
It is imperative that your project stakeholders never lose sight of your community’s main objectives: To increase the resiliency, and the social and economic viability of your community’s future.
Funding for flood mitigation projects can take many forms and will be largely dependent on the project type being pursued. Be sure to check for project funding from federal (such as FEMA Hazard Mitigation Grant Program (HMGP) and Department of Housing and Urban Development (HUD)), and state grants and low interest loans.
Also, many communities earmark funds in their capital improvement plans, funds from sales tax revenue, or sales tax levies and special assessments. Because of the complexities involved in raising the necessary funds, in most cases, you will not only need to get review and approval by the applicable governing agencies, but you will also need to secure project buy-in from area businesses and local residents.
As you build your flood mitigation projects and your resiliency increases, area businesses, residents and community leaders will begin to experience the benefits of these flood mitigation efforts. These benefits include a noticeable reduction in flood damage; improvements in community safety, infrastructure and aesthetics; increases in community pride and peace of mind; greater economic and social stability; increases in more resilient commercial and residential development; and an increased tax base and quality of life.
But, if you don't have the resources or the time to create a long-term plan, there are some things you can do in the short-term to beef up your city's flood resiliency.
Most importantly, make sure they are communicated to your community, and the residents understand they are all at risk.
The Flood Control and Coastal Emergency Act (PL-84 Authority) is one way the federal government can provide funding and expertise during disasters and emergencies.
FEMA Hazard Mitigation Grant Programs (HMGP) can provide funding to elevate your community's structures, among other benefits.
Sandbags and plywood will be very helpful to prevent the spread of flooding in high-risk areas. This means all the way down to the residential level, as well. Preparedness is key.
Make sure residents who are at risk know they are at risk, and that they are prepared to relocate in the short-term.
Do you have an evacuation plan? How will you know if the river will flood, or even your neighborhood pond? Know what information is available. Make sure operating and emergency action plans are up to date. You’re only as good as the efforts you put in.
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 floodway 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 or not the City should require floodplain residents to purchase flood insurance. 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. Instead of 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.
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