Corps of Engineers to Issue Repair Update Wednesday, March 9
March 7, 2016
Updated March 14, 2016
The US Army Corps of Engineers, Galveston District, is holding a public meeting Wednesday, March 9, 2016, to update the public about progress in repairing the Addicks and Barker dams on South Mayde Creek and Buffalo Bayou in rapidly developing west Houston.
The two earthen dams, completed in the 1940s, were labeled “extremely high risk” in 2009 when engineers noticed seepage around the dams’ gates and ends following a heavy storm. The “extremely high risk” designation did not mean the dams were in danger of failing soon. But the possibility of failure combined with the dams’ location upstream of a major metropolitan area lifted the dams into the urgent category.
As a result, the reservoirs, which are dry reservoirs and contain one of the region’s largest parks and recreation areas, cannot be filled to capacity during storms, which impacts the way water is released from the dams before and after storms: faster and more often. (Correction: The Corps of Engineers says that the structural problems with the dams have had no impact on the capacity limit or release rates.) This unnatural flow regime in turn impacts Buffalo Bayou downstream. (South Mayde Creek joins Buffalo Bayou just below the dams.) However, most of the flooding in Buffalo Bayou during heavy storms is caused by surface runoff from buildings, highways, streets, parking lots, and other paved surfaces below the dams, which are closed during rain events.
Until recently releases from the dams, combined with existing flow in the bayou, were limited to 2,000 cubic feet per second (cfs) as measured by the Piney Point gauge. In 2010, however, the Corps received permission to increase the flow to 4,000 cfs if necessary, the point beyond which severe flooding is expected to occur. (See also dam operation, pdf, page 2.)
Following the Memorial Day flood in 2015, the Corps began sustained releases reaching 3,000 cfs for the first time. (See Item V, Minute 3:25, appearance by Flood Control District Director Mike Talbott before Harris County Commissioners Court, June 2, 2015.)
The public meeting on Wednesday will address the Addicks and Barker Dam Safety Program, the 2016 Addicks and Barker construction plans and the proposed Section 216 Study. The meeting will take place from 6:30 to 8:30 p.m. at the Bear Creek Community Center, 16001 Clay Road, Houston 77084
In 2015 the USACE Galveston District awarded a contract in the amount of $71,902,340 to Granite Construction Company for construction of new outlet structures at the dams. Construction, expected to begin in September, began in February. Completion is projected for summer of 2019.
A Section 216 study is required by Section 216 of the federal Water Resources Development Act of 2000 whenever there are changes in the operations and management of a water resources project. However, the study cannot take place until it is authorized and funded by Congress, says Richard Long, supervisory natural resources manager for the Galveston District.
“First and foremost, these dams are not in danger of failing,” says Col. Richard Pannell, commander of the Galveston District, in a press release. “Addicks and Barker are dry reservoirs about 90 percent of the time, and they undergo daily, weekly and annual inspections and monitoring. While the likelihood of overtopping or failure is very low, the fact the dams protect the nation’s fourth largest metropolitan area makes the consequences to life safety relatively high risk.”