Flooding Begins on the Land
June 2, 2021
Save Buffalo Bayou believes that the focus of flood-risk and floodplain management should be on stopping stormwaters before they flood our streams. And while riverine flooding is only one aspect of our regional and state flooding problem, the goal of collecting as much stormwater as possible and moving it as quickly as possible is outdated, ineffective, and should be dropped. Enlightened practice focuses on managing flooding in place, stopping raindrops where they fall, and spreading out, slowing down, and soaking in the rain.
As a 2018 study of urban flooding reported, “[m]any cities and towns across the United States are giving considerable attention to plans that support the capture of rain in areas where it falls.” (p. 32)
We hope that the technical committee and the San Jacinto Regional Group will address the role of individuals, neighborhoods, homeowners’ associations, businesses, communities, cities and counties in reducing flood risk. Shared policies and strategies should be developed explaining, encouraging, even requiring responsible stormwater management from rooftops to parking lots.
The state flood planning guidelines do require consideration of the fundamental importance and beneficial function of floodplains. (p. 87) We would also point to this 2014 report by the American Society of Civil Engineers, which criticized the “tendency, for both historical and psychological reasons, to place greater reliance on traditional structural measures [dams and reservoirs, digging up bayous, for example] even though in the long run nonstructural and nature-based measures tend to be more efficient and sustainable solutions.” The report called for a national flood risk management strategy. (p. 27)
What Other Cities and States Are Doing
In that regard, we thought it would be useful to point out what some other cities and states are doing.
As a general though not exhaustive list, these practices include:
Green roofs, rain gardens, etc.
Cities like Toronto and Utrecht require green roofs, which can reduce stormwater runoff by more than 50 percent. (Toronto provides financial assistance.)
Simply disconnecting roof downspouts from the public stormwater drainage system can help prevent the system from being overwhelmed, a practice recommended by the Environmental Protection Agency.
From California to Illinois to New England, cities are asking residents to disconnect downspouts and instead allow rainwater to flow and soak into a yard, among many other things. (Directing roof runoff onto a concrete driveway, seemingly common practice in Houston, is not helping, since it runs directly into the paved street and into the stormwater system anyway.)
Protection of riparian corridors
The policy of stripping, channelizing, deepening and widening streams to speed up the flow of stormwater should be abandoned. The destruction of our remaining natural streams is only leading to increased flooding and erosion and increased and continuing costly maintenance.
The technical committee must address the dangerous and contradictory policies of “improving conveyance” in streams that feed into our federal flood control reservoirs on Buffalo Bayou when those reservoirs already are disastrously unable to handle a major storm like Harvey.
Denton County in north Texas has adopted an admirable plan to protect greenbelts along its streams, complete with programs to educate property owners and developers about why this is important. The state of Vermont is aggressive about protecting the natural functions of its streams and prohibiting property owners from making changes that would impair that.
Permeable paving and “daylighting” streams
The TWDB technical guidelines do mention Green Stormwater Infrastructure. (p. 88) This would include encouraging (requiring?) a greater use of permeable pavement, and, of course, trees, parks, and greenspace that can divert, absorb, disperse, hold, slow down, and filter rain runoff. “Daylighting” streams (streams, creeks, etc. that have been buried in concrete pipes) would also be considered green, as are open ditches. We have many creeks and ravines that have been filled in (and built on, flooding as a result). It might be useful to identify where that has happened.
Recommend statutory changes and increased funding
The technical committee and the regional group should address the limited legal tools and outdated function of the Harris County Flood Control District, established in 1937, and make recommendations for statutory changes that can bring the district into the modern flood management era.
The technical committee and regional group should request the federal government to provide adequate funding and staffing to the regulatory branch of the US Army Corps of Engineers so that it can properly fulfill its legal obligation to protect federal waters and wetlands so vital for reducing flooding.
Here is what some other cities (and states) are doing or suggesting to make themselves more like “sponge cities”:
Wuhan, also Shanghai and other cities
President and Executive Director