How Carmel, Indiana tamed flooding despite increasingly powerful storms

May 2018

My city used to have a flooding problem. Back in 2003, an intense Labor Day storm dumped eight inches of rain on central Indiana, turning Carmel’s streets into rivers. Firefighters couldn’t respond to medical emergencies in their usual rapid manner and had to reach those in need, including a heart attack victim, by boat.

Severe rainstorms, like other extreme weather events, have become the new normal due to climate change. Between 1958 and 2012, heavy downpours increased by 37% in the Midwest, according to a report from the National Climate Assessment. Despite stronger and more frequent storms, we’ve managed to greatly reduce flooding events for Carmel’s 100,000 residents by taking action to reduce our risk. One way that I know our actions are working is that the volume of calls my office receives from residents after a storm has fallen by 95%.

Part of Greater Indianapolis, Carmel’s landscape makes it at risk of flooding for a number of reasons. The White River forms our eastern border, and several streams and creeks snake through the town. The area’s terrain is Midwest flat, with clay soil that doesn’t absorb water very well.

To address the problem of flooding, we instituted a stormwater district utility fee in 2014. Adding those funds to local tax revenue, we’ve spent roughly $40 million to increase the capacity of our drainage system. This system is largely made up of swales (ditches that help manage water runoff) along the sides of roads and underground piping. With the assistance of our City Engineer, Jeremy Kashman, we’ve prioritized the most flood-prone streets and areas, designing a system capable of handling eight or nine inches of rain in a day’s time. We’re also experimenting with more absorbent materials, such as porous concrete and asphalt, adding green medians to streets, and planting native flora in the swales to filter out contaminants that otherwise end up in our streams and drinking water.

Reducing flood risk is also a component of our sustainable city planning, with the aim to reduce local greenhouse gas emissions. We’ve redesigned the town center for people rather than cars, in some areas removing concrete and creating green spaces in an effort to improve flood resilience. Carmel’s re-imagined downtown is walkable and mixed-use, featuring both residential buildings and a variety of local businesses, as well as arts and entertainment. The city had only 41 acres of parkland when I began my first term as mayor in 1996, and today we have nearly 1,200 acres. We also have roughly 200 miles of bike trails within the city, up from zero back then.

The residents of Carmel consider the improvements to their safety and quality of life as money well spent. Nobody wants to pay fees or taxes, but if they know what the money is being used for and see the improvements, they’re generally supportive. We’ve also chosen projects that benefit the community beyond just reducing flood risk. The key here is effective communication. We communicate where the dollars go in detail through our public access channel, local media, and neighborhood association newsletters.

In 2017, the US experienced a historic year of weather and climate disasters, according to the National Oceanic and Atmospheric Administration. Sixteen separate billion-dollar disasters hit the country, including three hurricanes, eight severe storms, two inland floods, a crop freeze, drought, and wildfires. These events will continue to challenge cities and towns across the country. We can spend the money on sustainable and resilient planning now, or we can pay a whole lot more later.

James Brainard is the six-term mayor of the City of Carmel, Indiana.

For more information on how communities are taking action, click here.