Recreating a Natural Bayou to Prevent Flood Damage

Kevin Shanley, ASLA, now CEO of the SWA Group, partnered with the local Sims Bayou Coalition in Houston to re-design a massive federal flood damage reduction project. The flood mitigation project was originally planned to be a straight, man-made, concrete channel; Shanley instead proposed a natural, meandering bayou. According to The Houston Chronicle, “the flood-control project was of an entirely different scale: It concerned nearly 20 miles of Sims Bayou, stretching from the Houston Ship Channel almost to South Post Oak . But the tiny Sims Bayou Coalition desperately needed professional help to negotiate with the flood-control district. When Shanley offered his services, the members hoped he could find ways to mitigate the project, make its footprint smaller, its ugliness less unbearable.”

Shanley studied “fluvial geomorphology,” the way rivers shape themselves, in an effort to develop a new proposal which would reflect the natural flow of bayous. According to The Houston Chronicle, “bayous are slow rivers, ones that meander over flat land toward the sea. In flood control, faster was considered better. The goal was to rush rainwater into the bayous, then hustle it out to sea. Rivers, though, don’t like to be rushed. They don’t like to flow in straight lines, and they’re wider in some places than in others. In low spots, they regularly overflow their banks. Wildlife loves those wetlands.”

The district had available large blocks of land, which the Sims Bayou cuts through diagonally. “The district, Shanley realized, owned a lot more land than it needed for a straight, deep channel.” Shanley used this extra land to develop a new proposal featuring a more natural, meandering bayou. Ideas that guided the proposal: “What if you let Sims Bayou meander? What if, instead of rushing the floodwater out toward the Gulf, you gave it a place to collect safely? What if you made the bayou wider and curvier — able to hold more water but also slower? What if, instead of paving it with solid concrete, you bolstered the banks with concrete that grasses could grow through?”

The plan was presented to neighborhood activists and flood control engineers. While some neighborhood groups were concerned that the new plan took up more land (as more room is needed for a natural bayou’s movement), “the engineers, to his surprise, were intrigued. And when they ran sophisticated flood-control models on Shanley’s plan, they found that it worked better to control flooding than their original proposal.” The new idea became the basis behind the Sims Bayou Federal Flood Damage Reducation project, expected to finish in a few years. The Houston Chronicle writes that the flood-control district will lead to the removal of 35,000 houses and 2,000 businesses from the 100-year flood plain.

The Houston Chronicle added that neighborhood groups have also now largely embraced the plan. “The project, complete with fish ponds and trees, is great to look at. Wildlife thrive on its banks. And when the bayou isn’t at flood stage, the land can be used for other purposes. “‘The Hill at Sims Greenway,’ for instance, is a 60-foot-tall hill created from the dirt dug from a big hill storm-water detention pond near Scott and West Orem.”

Additionally, SWA group worked on the Buffalo Bayou Promenade, led by the Buffalo Bayou Partnership, which won an ASLA 2009 Professional Award of Excellence.

Read the article and learn more about the project

Image credit: Kevin Shanley

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