Cutting Forest for Stormwater Basins
Is that A Good Idea?
The Value of Lost Ecosystem Services
April 29, 2025
Digging out the land to create basins to hold stormwater and prevent flooding is a good thing. But is cutting down forests of trees a good way to do it?
A study commissioned by Save Buffalo Bayou has found that removing forests to dig out stormwater basins results in the significant loss of vital ecosystem services.
Trees, especially a forest of old trees, provide numerous benefits. In addition to slowing and reducing stormwater on their own, protecting and stabilizing streambanks, trees and plants help cleanse and cool the air, provide habitat and help sustain biodiversity, and help us maintain our mental, physical, and emotional health, among many other things, like nourishing the water table, preventing subsidence, and more.
For years now the Harris County Flood Control District has been clearing hundreds of acres of forests alongside streams to create detention basins. These types of basins are generally designed to temporarily divert water from flowing streams, as opposed to upland basins that collect rainwater running over the land.
Of course, the district was created in 1937 to help the US Army Corps of Engineers strip, straighten, and encase in concrete our then-forested rivers and streams. (See Brays Bayou and White Oak Bayou, for instance, both formerly wooded and winding.) But that project was stopped in the early 70s, initially by environmentalists. It is now generally accepted that stripping and channelizing streams to make water flow faster only increases flooding. Slowing the flow is the way to go. Stop the runoff before it floods the stream. (See also here.)
It might come as a surprise that Harris County has so much forest. Though largely coastal prairie, historically the many streams, creeks, and rivers that wind through the county towards the gulf have been lined with magnificent forests of oaks, pines, sycamores, cottonwoods, and more. They are called riparian forests.
It might also come as a surprise that the Harris County Flood Control District, in its founding charter, was tasked with the seemingly contradictory responsibility for the “conservation of forests.” (p. 1, section 1) Unfortunately, the county has lost some 10 percent of its tree canopy between 2011 and 2021, according to recent report from Rice University’s Kinder Institute.
The world is losing its forests, a cause for global concern. But what is the local impact of removing forest in our own part of the world? And is there a better approach to reducing floodwaters?
Save Buffalo Bayou, with the help of the Jacob and Terese Hershey Foundation, commissioned a study to evaluate the loss of ecosystem services from deforestation, including removal of the soil. The study looked at four detention basin sites from a variety of watersheds and landscape contexts: Clear Creek in southeast Harris County, Cypress Creek in northwest Harris County, and two on Halls Bayou north of Houston.
To quantify the value of ecosystem services contributed by each of these sites before and after excavation, the study used the Ecosystem Services Valuation Tool developed by Earth Economics and the Land Trust Alliance. (p. 12)
The study also looked at the water storage capacity of the top five-foot layer of soil prior to removal at each site.
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