Over 1,200 People at Telephone Town Hall About Deepening, Widening Buffalo Bayou
Public Comment Deadline is Nov. 20
Nov. 16, 2020
The Corps of Engineers is “going back to look at tunnels” to move stormwater from west Houston that can no longer be handled by the federal flood control dams there, said Col. Timothy Vail, commander of the Galveston District, during a telephone town hall sponsored by 7th Congressional District Rep. Lizzie Fletcher.
The conference call Sunday evening drew over 1,200 people concerned about the Corps’ proposals for dealing with too much stormwater flowing too fast into the 70-year-old federal dams, Addicks and Barker, in western Harris County north and south of Interstate 10.
During Hurricane Harvey in 2017, stormwater runoff held back by the dams flooded properties built in and behind the reservoir pools. When stormwater threatened to spill around or over the top of the earthen dams, the Corps was forced to open the floodgates, flooding thousands of properties along Buffalo Bayou immediately downstream from the dams.
In an Interim Report on its $6 million Buffalo Bayou and Tributaries Resiliency Study, the Corps proposed as one possible solution deepening Buffalo Bayou by almost 12 feet and widening it to some 230 feet for 22-24 miles from the dams to downtown Houston (actually to 1,500-feet below Montrose—about Stanford Street). This would be to accommodate a flow of 15,000 cubic feet per second (cfs).
In “areas of high erosion,” the Corps would use articulated concrete block to line the channel bottom and banks. However, articulated concrete block doesn’t work in Buffalo Bayou, where the primary type of bank collapse is vertical slumping. The weight of concrete block exacerbates slumping.
The Corps also suggested building a dam on Cypress Creek with a reservoir on 22,000 acres of the Katy Prairie to hold back floodwater overflowing the creek and draining south into Addicks Reservoir.
Impacts
The Corps admits that deepening and widening the bayou would basically eliminate all aquatic life in the bayou, including the threatened Alligator Snapping Turtle. The report, released Oct. 2, does not explain how it would purchase the property to eliminate wide swaths of the largely privately-owned upper bank of the bayou, how it will handle the proliferation of concrete and steel erosion control structures, public and private landscaping, the natural sandstone in the channel bottom and banks, or what happens in downtown Houston when a flow of 15,000 cfs hits below the Sabine Bridge—or a storm surge coming the opposite way.
Currently at that level of flow, floodwater inundates the trails in Buffalo Bayou Park and begins creeping towards Memorial Drive and Allen Parkway. The upper channel in the park was about 120-150 feet wide, according to Google Earth, before the Harris County Flood Control District spent nearly $10 million in federal funds narrowing the channel and lining the banks with concrete riprap in the last year.
The dam and reservoir on Cypress Creek would inundate a large portion of the remaining Katy Prairie, much of it under conservation easement, and ruin the prairie’s natural ability to slow and absorb stormwater by killing off the vegetation. (pp. 175-176)
Better Options
Save Buffalo Bayou, with other environmental organizations, supports green, nature-based solutions at the regional, community and neighborhood levels. We are opposed to deepening and widening Buffalo Bayou and a dam on Cypress Creek, which the Corps admits will likely only encourage more development and thus more stormwater runoff. (p. 175) (And once again place more people in harm’s way).
Deepening and widening streams increases flooding, among many other problems. Focusing on stopping and slowing stormwater, on managing flooding in place, is the modern, more effective, more practical approach. The Corps’ simultaneous Metropolitan Houston Regional Watershed Assessment was supposed to be looking at a more comprehensive approach to reducing flood risk, though the scope of the study seems to have changed since it was first funded. At a recent virtual meeting, Col. Vail said that regional assessment would be considered.
The Katy Prairie Conservancy, also opposed to deepening and widening the bayou and the reservoir on Cypress Creek, has proposed alternatives.
However, the Corps in its Interim Report said that nature-based alternatives had been “screened out.” (p. 6)
