Nov. 20, 2020
Col. Timothy Vail, Galveston District Commander, US Army Corps of Engineers
Andrew Weber, Project Manager, Buffalo Bayou and Tributaries Resiliency Study
CC:
Russ Poppe, Executive Director, Harris County Flood Control District
Harris County Judge Lina Hidalgo
Harris County Commissioners Precincts 1,2,3,4
Mayor Sylvester Turner
Houston City Council
Rep. Lizzie Fletcher, 7th District
Rep. Dan Crenshaw, 2nd District
Sen. Ted Cruz
Sen. John Cornyn
Esteemed Engineers,
We appreciate the extended period to comment on the Galveston District’s Interim Report for the Buffalo Bayou and Tributaries Resiliency Study. However, we are deeply disappointed by the outdated, incoherent proposals contained in it.
This proposal purports to address the problem of too much stormwater flowing into the federal dams on Buffalo Bayou in west Houston during major storms. Unfortunately, it fails. In fact, if enacted, the proposals could make flooding worse.
The report violates the Corps’ Environmental Operating Principles,[1] [2]most blatantly in its outright rejection of nature-based alternatives.[3]
The centerpiece of the proposals is “improving conveyance” in Buffalo Bayou. Yet, modern science has shown that “improving conveyance” doesn’t work,[4] that it only causes more flooding and erosion.[5][6][7][8]
Creating capacity to convey more and faster rainwater runoff encourages the production of more and faster runoff. As the excellent Greater Houston Flood Mitigation Consortium reported in 2018, “conveyance projects can make flooding worse.”[9]
Furthermore, digging out Buffalo Bayou will only lead to extensive bank collapse and continued costly maintenance. (Who will pay for that?) The river will try to adjust to its natural and necessary shape.
Yet, in areas where the bayou is naturally deepening and widening, the Corps plans to stop that. This makes no sense.
Note that articulated concrete block doesn’t work in Buffalo Bayou.[10] Neither the Corps nor the Harris County Flood Control District seems to understand that the primary form of bank instability in our bayou is mostly from slumping, sliding down vertically.[11] This happens no matter the steepness of the slope. Adding the weight of concrete block, which is designed for erosion caused by horizontal flow, only increases the likelihood of collapse, according to our experts and common sense.
Does the Corps plan to determine “areas of high erosion” before or after they bulldoze the entire thing, which will lead to “areas of high erosion” everywhere?
Does the Corps realize that Buffalo Bayou is largely lined with sandstone on the sides and bottom? This sandstone has been there for at least 100,000 years.
The Corps admits the plan for Buffalo Bayou will eliminate all aquatic life in the bayou.
Deepening and widening will remove the trees and vegetation and contribute to increased sedimentation, pollution, and higher, more erosive flows.
There is no way for the Corps to mitigate the disastrous environmental impact of destroying such a large and vital natural stream.
The Corps in its cost benefit analysis did not put a financial value on the loss of environmental benefits and functions of the bayou or the prairie, which include holding, slowing, absorbing, cleansing polluted urban and agricultural runoff, not to mention the growing local[12] and worldwide problem of biodiversity loss.
The proposal is impractical, backwards, and contradictory. Some of the contradictions:
The bayou naturally deepening, widening, dredging itself is bad. But spending billions to do the same thing artificially is good.
There’s too much water flowing all at once into the dams during storms, so we should spend millions increasing the flow of streams behind the dams. See the Corps’ plan for Cane Island Branch and ongoing projects by the Harris County Flood Control district to speed up the flow of stormwater through tributary streams into Addicks[13] and Barker[14] reservoirs.
The Corps says that excavating the reservoirs would cause unacceptable environmental damage, but somehow excavating Buffalo Bayou would be acceptable. We think the functional environmental damage on both counts is unacceptable.
We are opposed to the deepening and widening of Buffalo Bayou and to the construction of a dam and reservoir on Cypress Creek and the Katy Prairie. The Corps admits that the Cypress Creek dam would destroy the beneficial, flood-mitigating functions of a large amount of prairie and likely encourage increased development and increased runoff below that new dam into Addicks Reservoir, once again encouraging people to move into harm’s way, negating any benefit of the dam.
No authority seems to want to operate or pay for operating and maintaining a new dam.
Further Questions:
Does the Corps plan to remove the numerous privately funded erosion control structures on the bayou and compensate owners for the loss? Or will the burden of property loss from widening the channel be placed unequally on property owners, including the public, on the opposite bank or where owners have wisely chosen to leave their banks natural?
Does the Corps plan to pay for restoring and re-landscaping our public parks on Buffalo Bayou?
The Interim Report does not address the issue of tidal surge in Buffalo Bayou, which is tidal through downtown Houston past the Shepherd Bridge, and what happens when a massively increased volume of stormwater hits a powerful high tide coming the opposite way; or, for that matter, what happens when the powerful, fast-moving flow towards the east hits the still relatively narrow channel closer to downtown.
We would like to see the models and numbers that led to the Corps’ conclusions, including but not limited to:
“If the dams were to be removed, the loss of benefits in the form of flood damage reduction in single-event damages is estimated to be $41,600,000.”[15]
The proposed depth and width for Buffalo Bayou.
Alternatives
We support the Katy Prairie Conservancy’s alternatives,[16] except for the concept of flood tunnels.
We think the focus should be on managing flooding in place,[17] on slowing, stopping, spreading out and soaking in rainwater before it floods our streams.[18] Nature-based, green. Trees, prairies, wetlands, wooded parks, meandering natural streams; rain gardens, swales, vegetated ditches, porous surfaces, green roofs, etc. See our page of Books and Articles about Buffalo Bayou, Rivers, Flooding, and Nature for more information.[19] See also the City of Houston’s Resilient Houston report[20] and Harris County’s Harris Thrives Resolution.[21]
We encourage the Galveston District to wait for and put serious effort into the original focus[22] of the Metropolitan Houston Regional Watershed Assessment.
We also think the Corps should look at the many stormwater outfalls, old and new in Buffalo Bayou, that violate the requirements of the Harris County Flood Control District’s Regional General Permit. Many of these large pipes angle directly across the stream, blocking the flow and causing turbulence and erosion.[23]
We also think the Corps should look at reuse of all this problem stormwater.[24] It is problematic that authorities are spending billions of dollars to build 55 miles of pipes to bring drinking water from east to west Houston[25] while at the same time proposing to spend billions of dollars to transport water the opposite direction.
We support buying out properties that are in harm’s way as well as properties to be used as restored floodplain, wetlands, and vegetated greenspace and detention.
Susan Chadwick
President and Executive Director
Save Buffalo Bayou
[1] Environmental Operating Principles, US Army Corps of Engineers, Galveston District. https://www.swg.usace.army.mil/Missions/Environmental/Environmental-Operating-Principles/
[2] Engineering with Nature, US Army Corps of Engineers, Engineer Research and Development Center. https://ewn.el.erdc.dren.mil/About.html
[3] Interim Report Key Terms and FAQs Final, Buffalo Bayou and Tributaries Resiliency Study, Galveston District, US Army Corps of Engineers, Oct. 1, 2020, p. 6 https://www.swg.usace.army.mil/Portals/26/BBTRS%20Interim%20Report%20Key%20Terms%20and%20FAQs%20Final%20%2810_07_2020%29.pdf
[4] “Taming the Mighty Mississippi Might Have Caused More Floods,” Stephanie Pappas, Scientific American, April 10, 2018. https://www.scientificamerican.com/article/taming-the-mighty-mississippi-may-have-caused-bigger-floods/
[5] “Practices to reduce flooding risk are out of line with our region’s needs,” Susan Chadwick, Houston Chronicle, Jan. 23, 2017. https://www.houstonchronicle.com/opinion/outlook/article/Chadwick-Practices-to-reduce-flooding-risk-are-10877720.php?t=425a551bac438d9cbb&cmpid=twitter-premium&utm_campaign=twitter-premium&utm_source=CMS%2520Sharing%2520Button&utm_medium=social&utm_campaign=twitter-premium&utm_source=CMS%20Sharing%20Button&utm_medium=social
[6] “Why Dredging Makes Flooding Worse,” Charles Rangley-Wilson, Dec. 19, 2015. https://charlesrangeleywilson.com/2015/12/19/why-dredging-makes-flooding-worse/
[7] “DREDGING: Is it a Good Solution to Flooding Problems?” New York State, Dept. of State, Nov. 2012. http://www.stcplanning.org/usr/Program_Areas/Flood_Mitigation/Beneficial%20Functions/Dredging_Factsheet.pdf
[8] “Natural Defenses from Hurricanes and Floods,” National Wildlife Federation, 2014, p. 50 https://www.nwf.org/~/media/PDFs/Global-Warming/2014/Natural-Defenses-Final-Embargoed-Until-102114-10amET.pdf
[9] “Greater Houston Strategies for Flood Mitigation,” Greater Houston Flood Mitigation Consortium, April 9, 2018, p. 17. https://www.houstonconsortium.com/graphics/StrategiesReport_pages.pdf
[10] Failed Erosion Control in Buffalo Bayou, video by Save Buffalo Bayou, 2017. https://www.youtube.com/watch?v=DOX4ve3iE00
[11] “Help, the Bank Slid Away,” Save Buffalo Bayou. https://www.savebuffalobayou.org/?page_id=4661
[12] “Resilient Houston,” City of Houston, p. 105. https://www.houstontx.gov/mayor/Resilient-Houston-20200518-single-page.pdf
[13] F-53, Rehabilitation of Channels Upstream of Addicks Reservoir, Harris County Flood Control District. https://www.hcfcd.org/Find-Your-Watershed/Addicks-Reservoir/F-53-Rehabilitation-of-Channels-Upstream-of-Addicks-Reservoir
[14] F-52, Rehabilitation of Channels Upstream of Barker Reservoir, Harris County Flood Control District. https://www.hcfcd.org/Find-Your-Watershed/Barker-Reservoir/F-52-Rehabilitation-of-Channels-Upstream-of-Barker-Reservoir
[15] Interim Report, Buffalo Bayou and Tributaries Resiliency Study, Final. Oct. 1, 2020, p. 174 https://www.swg.usace.army.mil/Portals/26/BBTnT_Interim_Report_202001001_Final_1.pdf
[16] “KPC Alternative Concepts, Buffalo Bayou and Tributaries Resiliency Study,” https://www.savebuffalobayou.org/wp-content/uploads/2020/11/KPC-Prairie-Solution-for-Reducing-Flooding-2020_10_26-FINAL.pdf
[17] “Managing Flooding in Place,” Steven Eubanks, Chief Stormwater Engineer, City of Fort Worth, January 2018. https://www.savebuffalobayou.org/wp-content/uploads/2018/01/Managing_Flooding_in_Plac.pdf
[18] Floodplain Management: A New Approach for a New Era, Frietag et al, Island Press, Washington, D.C. Sept. 2009. https://islandpress.org/books/floodplain-management
[19] Books and Articles about Buffalo Bayou, Rivers, Flooding, and Nature. https://www.savebuffalobayou.org/?page_id=4850
[20] Resilient Houston, City of Houston, May 18, 2020. https://www.houstontx.gov/mayor/Resilient-Houston-20200518-single-page.pdf
[21] Harris Thrives Resolution, Harris County Commissioners Court, Houston, TX, Aug. 27, 2019. https://files.constantcontact.com/81a41547001/98fd956e-4e6a-4f0e-bd37-f1fbe2a12b72.pdf
[22] Draft Proposal, Metropolitan Houston Regional Watershed Assessment, Galveston District, US Army Corps of Engineers, Sept. 13, 2017. https://www.savebuffalobayou.org/wp-content/uploads/2018/02/Regional-Watershed-proposal-9.13.17-1.pdf
[23] “You Blockin’ My Bayou: Outfalls Right and Wrong,” Save Buffalo Bayou, Dec. 16, 2019. https://www.savebuffalobayou.org/?p=7964
[24] Circular Water Systems in Urban Areas. https://www.circularwatersystems.eu/
[25] Surface Water Supply Project. https://www.surfacewatersupplyproject.com/
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