Mitigating Increasingly Intense Rainfall in St. Louis
- Published on Wednesday March 1st, 2023
Author: Anna Chott, Sustainability Planner at East-West Gateway Council of Governments
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Brentwood Bound Park in progress, part of the Brentwood Bound Plan to overcome flooding challenges and restore the natural floodplain for Deer Creek.
Photo credit: Planning Design Studio
The U.S. Global Change Research Program confirms heavy precipitation is becoming more intense and frequent across most of the United States. In St. Louis, the rains of July 2022 caused extensive, costly damage to public transit infrastructure and homes. In urban areas where natural, porous surfaces have been paved over, intense bursts of rainfall can result in such flooding. As Daniel Swain, climate scientist at the University of California, Los Angeles, said in an article in The Washington Post, “It is precisely that type of flooding, urban flooding and flash flooding from shortish duration but very high-intensity downpours, that is expected to increase the most in a warming climate.”
It is critical for cities to plan ahead for massive flooding events. The City of Brentwood is working on a comprehensive solution to mitigate flooding, the Brentwood Bound Plan. Their floodplain restoration project is a response to the long history of flooding on Manchester Road. The city’s fire department maintains a water rescue team and boat for this all-too-common occurrence.
Brentwood Bound aimed to restore the natural floodplain for Deer Creek and construct water retention basins. The city also revitalized an underused and water damaged area. They redefined the limits of the corridor so the restored floodplain would not be built on.
The downpour on July 26, 2022, tested Brentwood’s work. At the Rock Hill Stream Gage, there was 60% more water flow than in 2005 and 2015 storm events, and the water traveled through the restored floodplain without flooding Manchester Road. The pavilion, event lawn, and playground area situated near the main water retention basin did not flood either.
According to Great Rivers Habitat Alliance, a wetland will be part of the Brentwood Bound project, which will use native plants to collect stormwater, help prevent flooding, cycle nutrients, store carbon, and serve as a habitat for wildlife. Learn more about the project in this presentation by Brentwood Director of Parks and Recreation, Eric Gruenenfelder, at a Missouri Gateway Green Building Council event.
In addition to floodplain restoration, rain gardens are another tool to help manage stormwater. Tower Grove Park recently restored a stream that had been buried for 120 years. Five rain gardens now border the stream, capturing and redistributing stormwater. The stream would have been above ground when the Osage people lived in the area until their forced removal in the early 1800s. Tower Grove Park consulted with the Osage Nation’s Tribal Historic Preservation Office on the design of the project and intends for it to be a place where people can learn about the area's original inhabitants.
Residents and businesses can develop their own rainscaping projects with native plants, and various grants are available to fund these projects. St. Louis Metropolitan Sewer District’s Project Clear program awards rainscaping grants for landowners to complete their own stormwater mitigation projects. Past projects have included St. Louis FOOD Roof rooftop farm and rain garden and permeable pavement in the North Sarah development managed by the St. Louis Housing Authority. The Deer Creek Watershed Alliance also offers a rainscaping cost-share program for eligible landowners.
