Grand Rapids on flood mitigation: higher walls are not the solution

In the ongoing quest to improve the Grand River for human and ecosystem communities, one of the remaining barricades is the city’s floodwalls. Rising one foot above the 100-year flood recurrence interval—that’s 25 feet total height in places—the walls are a literal barrier to citizen connection with their river.  

For years, the floodwalls’ height has been a point of contention between the City of Grand Rapids and the Federal Emergency Management Agency (FEMA). The City has long maintained that the walls were high enough, while FEMA pushed for two feet of vertical additions. While two feet may sound inconsequential, the 2008 estimate for the cost of increasing the floodwall height by this amount was $9 million, according to MLive’s Garret Ellison.  

“When Katrina hit New Orleans, The Army Corps of Engineers was reevaluating flood protection throughout the nation,” said Christopher Reader, co-chair of the Green Grand Rapids Committee, “and our floodwalls are at the 100 year flood level. So what FEMA would like us to do is raise that flood protection.”

The push for greater flood protection is also linked to climate change, according to Rachel Hood, Director of West Michigan Environmental Action Council.

“We know that climate change is increasing the frequency and intensity of storm events,” she said. “We know that the EPA is strengthening stormwater rules. And we know that for the last decade, the City and FEMA have been negotiating the infrastructure investments that are needed to protect the city of Grand Rapids from flooding.” The city was built in a floodplain—protecting it from flooding is easier said than done.

Construction of Grand Rapids’ first floodwalls began in 1907. It was clear even then that the river, one of the primary economic boons for the city, also presented a significant risk whenever it burst its banks. In 2003, the walls were reconstructed to a height of one foot above the 100-year flood level. Now, with climate change threatening increased frequency and severity of storm events, flood protection demands even greater ingenuity.

“If you just raise the wall, in some places in the city you would be standing on the bank, right next to the river, right next to the wall, but not see the water because the wall would be so high,” said Reader. “And that was not our goal.”

“If we’re going to invest some money in the river corridor, we wanted to do it in a way that connects people back to the river rather than creating more barriers between people and the river,” said Hood.

Other cities across the United States faced the same dilemma—build higher walls, investing money and materials in barring citizens from river access, or take the hit of increased insurance rates and risk of flood damage?

“Many communities have been able to make the case and defend the position, and back it up with science, that we can control water differently through design and stormwater management practices.” Hood said.

The goal is to reach the necessary riverbank elevations using landscape design, rather than the traditional concrete walls. Managing the stormwater before it reaches the river is also key. Non-permeable concrete and asphalt surfaces, from which stormwater flows quickly into the river, will be augmented with more permeable surfaces, such as rain gardens.

Stormwater management techniques are moving away from the “gray infrastructure” tactic of using pipes to direct water, and toward the “green infrastructure”—landscape features that will capture and contain rainwater where it falls, allowing it to seep more gradually into the ground. These features, a far cry from concrete barriers and impermeable surfaces, actually serve as public facilities.

“One of the things we looked at is: how do we make our river an amenity?” said Reader. “Part of it is by allowing people access to it. So the response to having better flood protection was not bigger walls, but to move the protection farther away from the river, and use it as the base of a bike trail or part of another amenity.”

Tim Kelly, Planning Manager at Downtown Grand Rapids Inc., noted that, during the planning phase of GR Forward, “the importance of access was a number one priority that came out of our engagement.”

“The City essentially bought ten years of time,” said Hood. “And in that time… they took some risks, and pushed FEMA back a little bit in order to create a solution—a series of solutions—that take that $17 million we’re spending [on flood protection] and provide some really significant public benefit with it.”

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