State of the Bayou
Downed Trees. New Channel. New Riprap. Washed Out Sidewalks, Beavers, and Turtles
But Some Banks Naturally Rebuilding
Does It Make Sense to Repair?
Sept. 1, 2016
Updated Sept. 11, 2016
You could not step twice into the same river. Heraclitus
We finally had a chance recently to float down beautiful Buffalo Bayou to see how things have changed. Our trip took us past Memorial Park in the middle of Houston. We also biked along the bayou through Terry Hershey Park far upstream in west Houston below the dams to see what was happening there.
The good news is that some of the high banks that had slumped in Memorial Park and the Hogg Bird Sanctuary during the Memorial Day 2015 flooding are naturally rebuilding.
The bad news is that the River Oaks Country Club has added more riprap to the south bank, hard armoring the bank with ugly, damaging concrete rubble, including where it should not be.
Nature’s Miraculous Way of Restoring. For Free.
Houston has had multiple record-breaking rains and flooding since the spring of 2015. When Buffalo Bayou overflows its high banks, as it did in the Memorial Day flood of 2015, the banks in places sometimes slump or slide away. This happens when the overflowing water seeps through the ground and saturates layers of sandy clay that liquefy, sometimes causing the bank to give way. Buffalo Bayou is 18,000 years old, and this has been happening for a very long time.
This natural tendency to slump is one reason why we think attempting to engineer these banks as proposed by the $6 million Memorial Park Demonstration Project won’t work. It’s also the reason why we think building and repeatedly repairing sidewalks at the bayou’s edge is wasteful and foolish.
Dammed If They Do, Dammed If They Don’t
The Conundrum of the Buffalo Bayou Dams
Why so much water for so long in Buffalo Bayou?
May 26, 2016
The water in the normally empty reservoir had dropped only a few feet by the time we stood on the earthen dam looking down at the dark, opaque blue-gray surface. After almost a month, the rippling water below was still some twenty-three feet deep, and extended as far as we could see along the thirteen-mile long dam and far into the thousands of acres of flooded woods.
It had taken only a little more than twenty-four hours for the rains that began on April 18 to fill the vast flood control reservoirs in west Houston with a record amount of water: a total of more than 206,000 acre feet, a massive amount of water. Imagine 206,000 acres covered in a foot of water. Enough to cover more than eight times the acreage of both reservoirs to a depth of one foot. That much water would take an estimated four weeks to drain, according to reports at the time.
But that was only if there was no more rain. There was more rain, and it was taking much longer. The reservoirs, vast wooded parks with recreational facilities and nature paths, are still draining. As of May 24, the combined total of the two reservoirs was still about 90,000 acre-feet, down to a little less than half.
And Buffalo Bayou was still flowing high and fast, higher and faster for longer than ever before. Property owners upstream had flooded and property owners downstream who had hoped for more moderate flows were instead seeing long-standing trees falling into the fast-flowing stream, banks eroding, sediment collecting, debris causing water to back up onto their property.
Why was this happening and is there a way out of it?
Protecting Galveston, Houston, and the Texas Coast
Public Comment Needed By May 9
April 11, 2016
You may have heard about proposals to protect development along Galveston Bay, the Houston Ship Channel, and Houston itself from a giant storm surge. Dubbed the Ike Dike after Hurricane Ike in 2008, one leading plan is to build a 17-foot high levee for 50 miles along Galveston Island and Bolivar Peninsula, with a massive floodgate across the Houston Ship Channel.
Buffalo Bayou Runs Through It
But the Ike Dike is only one of several ideas being considered for the Houston-Galveston region by the US Army Corps of Engineers and the State of Texas. And in fact, in light of sea level rise (and due to subsidence, sea level is rising more rapidly on the upper Texas coast) and the potential flood damage from future storms, the Corps has been studying the entire Texas coast and gathering information for the past several years. In August 2014, the Corps issued a report called the Coastal Texas Protection and Restoration Project and held a series of four public workshops. And in May 2015 the Corps issued a Coastal Texas Protection and Restoration Study Final Reconnaissance 905 (b) Report.
A Notice of Intent to prepare a Draft Integrated Feasibility Report and Environmental Impact Statement for a Coastal Texas Protection and Restoration Feasibility Study, dated March 23, 2016, was published on the Corps’ Galveston District website. And on March 31 the Corps published a notice in the Federal Register calling for public comment on a draft Environmental Impact Statement for a Coastal Texas Protection and Restoration Feasibility Study. The public has only until May 9 to comment.
No Changes in Operation of Buffalo Bayou Dams
Release Rates May Be Looked At in Future
March 13, 2016
It was a dark and stormy night. Thunder boomed and heavy rain pelted the roof as a small group of us sat nervously in the middle of the rising Addicks Reservoir in far west Houston listening to the district commander of the Army Corps of Engineers tell us Addicks and Barker dams are safe.
Flanking Col. Richard Pannell last Wednesday, March 9, was a panel of officials from the Corps’ Galveston District office, as well as representatives from the Harris County Flood Control District and Granite Construction, the company awarded the $71.9 million contract to replace the leaky conduits in the 70-year-old earthen dams. The audience was a small crowd of about thirty hardy citizens who had braved the heavy traffic and heavy rain and managed to find the Bear Creek Community Center in the middle of a dark, wet forest despite the wrong address in the Corps’ public notice.
Col. Pannell made a thorough and convincing presentation of the history of the dams, the current problems, and what is being done about them. Among other work, the conduits in the two dams will be entirely replaced by new conduits in separate locations. This process will take about three years. He emphasized that the dams were in no immediate danger of failing and explained that the dams are labeled “extremely high risk” because of the potential consequences to Houston, the nation’s fourth most populous city, in the unlikely event that the dams failed.
Dams Operating Normally Despite Leaks
There were several questions about the capacity of the dams and the impact of repairs on the rate of future releases of water impounded behind the dams. The pattern of extended high releases and rapid drops has been criticized for damaging property on the bayou and killing trees and vegetation that control erosion.
After the enormous Memorial Day storm last year, the Corps began releasing impounded stormwater at 3000 cubic feet per second (cfs) for the first time. Normally the release rate is limited to 2000 cfs as measured by the Piney Point gauge. The Corps does not release water from the dams during a rain event, and the high releases began on June 1 and continued for ten days, finally dropping on June 12. The banks were already saturated from the storm, and the damage from the extended high flow was plainly visible up and down the bayou.
Public Meeting on Buffalo Bayou Dams
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.