If the Addicks and Barker Dams Fail
The psychic's office at South Highway 6's Briarhills Parkways strip mall would be one of the first ones to go. Later, jungle gyms and mailboxes painted in Texas state flag colors might join the bobbing televisions and tombstones from Memorial Oaks Cemetery in the crude river that's been formed by a breached Barker Dam.
North of Interstate 10, Barker's younger sibling, Addicks Dam, has also been wiped out by an unstoppable current that starts to overwhelm Buffalo Bayou.
Behind the swell, suitcases — left behind by evacuated guests of the Omni Hotel — thud against upper-floor windows of an Energy Corridor office tower. Further east on Katy Freeway, Bibles from area churches, unsliced foot-long bread rolls from a Subway and family pets float toward downtown like New Braunfels tubers.
Years afterward, as Houston continues to clear debris from the multibillion-dollar disaster, survivors might demand to know how this happened. Outdoor freaks who never could get over the loss of the soccer fields, bike trails, dog park and shooting range at George Bush Park, which had been built around Barker Dam, might relocate to the Hill Country to get their parks and rec fixes.
Others, while combing through the mangled ruins of the Texas Medical Center and River Oaks, could wonder if the psychic had seen it coming.
For more than 60 years, the Addicks and Barker dams have prevented an estimated $4.6 billion in flooding damages by limiting large amounts of water from reaching flood-prone Buffalo Bayou. But the dams, once located in the rural nothingness of Harris and Fort Bend counties, have been pushed to their limits, largely due to all of the people and buildings that currently coexist upstream and downstream of the dams.
In April 2009, during an unnamed weather event that leveled the west side with more than nine inches of rain in 24 hours, the dams exhibited signs of irreversible failure. Five months after the 2009 storms, the United States Army Corps of Engineers, which owns the dams, which are located near the intersection of Interstate 10 and Beltway 8, slapped Addicks and Barker with an "extremely high risk of catastrophic failure" label. The dams are currently two of the country's six most dangerous, according to the Corps.
Despite the Corps' "urgent and compelling" Dam Safety Action Classification I ranking, the local chapter of the Sierra Club, concerned residents and a professional engineer say the Corps has downplayed the risk — a member of the Houston Sierra Club says that she accidentally discovered the Level I distinction while researching other matters.
Additionally, in Sierra Club v. U.S. Army Corps of Engineers — filed on August 22, 2011, in the United States District Court for the Southern District of Texas, Houston Division — the environmental group alleges that the Corps tested fate when, in June 2011, they gave a thumbs-up to the construction of Segment E of the Grand Parkway (Highway 99). While some say the toll road is needed to keep up with fast-growing Houston, environmentalists say that the 15.2-mile segment between I-10 and Highway 290 will coax more concrete from housing and retail projects, which could send more water to the aging dams.
Local environmental attorney James Blackburn, who is representing the plaintiffs in the civil suit — currently in the appeals process after a district court sided with the Corps — says that if the dams broke, folks would have to deal with a lot more than soiled couches and temporary power outages.
"It could dwarf New Orleans and Katrina," says Blackburn, who adds that the Memorial Drive area, the Energy Corridor, River Oaks, the Texas Medical Center and maybe even downtown could be wading in nasty, disgusting floodwaters.
Not that everyone agrees. According to Michael Sterling of the Corps' Galveston District, Addicks and Barker dams aren't about to crumble. The Corps, which has put in a couple of quick fixes that may or may not work, says the soonest that Addicks and Barker can be fully repaired is by September 2017.
"All dams present risk potential; however, it is important to know that Addicks and Barker dams are not in imminent danger of failing," says Sterling, who adds, "The fact that the Houston metropolitan area is the nation's fourth largest population center is a primary concern. Any dam safety issues at Addicks and Barker could have a far greater impact due to the magnitude of people and property downstream as opposed to other dams around the country located in rural or low-population density areas."
Meanwhile, in order to prevent the reservoirs from getting too full, the Corps doubled the amount of water that can be released downstream. Properties and homes from Wilcrest Drive down to Chimney Rock Road could be flooded during a big storm, an issue that homeowners in the immediate flood plain aren't even aware of.
"I would say if you talk to 99 out of 100 people in West Houston and ask them about this problem, they wouldn't know anything about it," says Steve Rosencranz, a Sierra Club member and West Houston dweller. "It's something that nobody is talking about."
Though a Texas-based licensed professional engineer acknowledges that the dams were dry about 90 percent of the time during last summer's drought — a far cry from last week's heavy rain and flash-flood warnings that saturated Austin County down to Galveston — he says that it might not take an apocalyptic weather event to turn our town into the lost underwater city of Houston, Texas.
Before June 2001's Tropical Storm Allison, which destroyed 90 of 105 buildings on the University of Houston campus, and Hurricane Ike in 2008, dam-less Houston had to swim its way out of the devastating Memorial Day flood of 1929, which caused Buffalo Bayou to crest over the top of the Preston Avenue Bridge at more than 43 feet.
Six years later, during the Great Houston Flood of 1935, the city basically shut down after storms bombarded the Houston Ship Channel and downtown, turning 25 city blocks into a lake and causing an unheard-of $3 million in damages.
In response — and echoing similar flood-control projects throughout the country — the Corps of Engineers finished constructing the Barker Dam and Watershed (which sits on the south side of I-10) in 1945 and the Addicks Dam and Watershed (located on the north side of I-10) in 1948. The once mighty fail-safes, two of Harris County's 22 watersheds, were originally able to protect Houston from a 1,000-year flood.
However, the U-shaped, earthen dams have deteriorated because of an increased presence of stored water behind the structures, a consequence of more residential and commercial properties in what has become — or is becoming — urban West Houston and Katy.
Addicks and Barker have also been weakened due to the natural decline of dams that are made out of a big pile of dirt. According to a 2010 study released by the United States Society on Dams, soil and rocks that have been used in dam construction tend to deform, erode and lose strength over time. (Other nationwide Level I dams that need hole-plugging include two reservoirs upstream of Nashville, Tennessee, one in Piedmont, Missouri, and the Success Dam in California's Central Valley.)
As a result, Houston's most valuable and proven flood-control mechanisms might not be able to protect the city against a 25-year storm event, says Lawrence Dunbar, a former head of the Army Corps of Engineers' flood control and reservoir regulation section in Chicago.
Unlike Allison and Ike, which beat down upon east and northeast Harris County, the bursts of rain on April 27 and 28, 2009, did a number on the west side of town — Addicks Reservoir rose to just two inches short of its previous high, or the equivalent of a 25-year event. During the weather event that the Harris County Flood Control District later called "extreme," the Corps observed leakage in the dams, which are constructed with outfit pipes (known as culverts) and a gate that can be opened so that water can escape from the reservoir.
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"The Corps isn't quite sure how these voids got formed. Therefore, they're not sure if you get another big rain and the reservoir fills up again, even if it doesn't get high as it got before, they're not sure it can hold and voids won't form again," says Dunbar, a licensed professional engineer in Texas since 1983.
In the 1980s, the Corps installed concrete walls inside the earthen part of the dam to discourage leakage. However, the concrete wasn't installed above or below the culverts, which need replacing in the worst way.
"That's where they found these voids — under the culverts," says Dunbar. "What happens when a void forms is, it can basically let water blow through under the culverts or through the dam. When that happens, it's bad and dam failure is imminent. It's a big concern," says Dunbar.
In the meantime, the Corps is trying to win approval of an improvement proposal for Addicks and Barker dams. Ricky Villagomez, the Corps' Galveston District Project Manager, says a plan of action will be on the table in October; if approved, the three-year construction project would begin in October 2014. Even after the upgrades, the targeted lifespan of the reinforced dams tops out at 50 years.
For the Corps of Engineers to slap a dam with a skull-and-crossbones-type Level I designation, two criteria have to be met: What's the likelihood the dam will fail? And if the dam were to collapse into rubble, what would be the consequences in terms of economic damage and dead people?
After the 2009 deluge, the Corps of Engineers' Dam Safety Action Classification risk number for Addicks and Barker shot from an "urgent" Level II rating (which had been determined by the Corps in 2005) to the "urgent and compelling" Level I. Under the Corps' classification, Level I means that immediate action must be taken to avoid dam failure.
"From going to a II to a I, the consequences didn't change. The risk of failure must have increased," says Dunbar. "The Corps tried to downplay the Level I tag, but that's their designation. They're the ones that raised it to Level I, but then they said there's not an imminent danger of failure?"
"The Corps admits that the consequence of a failure is 'catastrophic,'" adds Dunbar. "It's unacceptable."
Evelyn Merz, conservation chair of the Lone Star Chapter and the Houston Regional Group of the Sierra Club, agrees that the Corps hasn't been upfront to home and business owners who could be S.O.L. In fact, says Merz, she stumbled upon the information while researching Sierra Club v. Federal Emergency Management Agency, a court case that concerns flood insurance maps for Cypress Creek-area residents.
"We came across a document in a Freedom of Information Act that pointed out that the Corps of Engineers had changed the operating plan for Addicks and Barker reservoirs due to the highest level of risk," says Merz about the July 2010 internal memo.
In an attempt to get some answers, Merz wrote letters to Harris County officials, the mayor's office and the Corps of Engineers. She scored a meeting with a Corps staff member on a Tuesday, but three days before, the Corps' Galveston District Regulatory Branch okayed the building of Grand Parkway's $350 million Segment E.
Merz and Blackburn were appalled. They say that Segment E and the potential development will reduce Katy Prairie's ability to retain runoff during major storms. That's because water travels faster on a paved chunk of land than it does across the spongy soil of the Katy Prairie.
The Houston Sierra Club is trying to halt the construction of the Grand Parkway's Segment E, claiming that the prospective toll road might have a devastating impact nobody can imagine. "The long-term effects are significant of what we will face if we don't get the issue of runoff controlled and accounted for in those watersheds," says Merz.
Because long-term improvements are at least five years away, the Corps' interim fix was to shave 975 years off of Addicks's and Barker's 1,000-year-flood capability. Currently, the reservoirs are permitted to hold only around 60,000 acre-feet of water, a level the reservoirs nearly reached during the April 2009 downpour.
Additionally, the Corps doubled the maximum amount of water that can be released downstream (from 2,000 cubic feet per second to 4,000 CFS). If reservoir water levels swell to 2,500 CFS, properties will start to flood. At 4,100 CFS, homes near West Beltway Bridge, North Wilcrest Drive and Chimney Rock Road could be marinating in floodwaters.
"In trying to protect the safety of the dams, which I have no problem with, they're saying better flooding a few homes than let the dams fail," says Dunbar. "They're pushing the envelope."
In the meantime, Dunbar believes that the Corps is crossing its fingers, hoping that a big storm doesn't sweep through the region.
"They or anybody can't tell you what the current risk of failure is because they don't know," says Dunbar. "They don't know if, during a ten-year event, if the water level rises to less than a 25-year event that it won't fail. They just don't know."
Dunbar says there's another issue to consider. During its risk analysis in 2009, the Corps discovered that the natural ground at the top of Addicks and Barker dams had subsided. If water started to spill over the top of the reservoirs — an unlikely but not impossible scenario — there might be hell to pay.
"When the reservoir fills up high enough, before it can spill over and out over the concrete part, it will start spilling out over the natural ground, which is dirt, which means it can start eroding right next to the concrete part of the dam," explains Dunbar. "It would create the same problem as if the concrete wasn't there."
If the reservoirs bubbled over with rainwater, Dunbar says, a 30-foot wall of craziness could be released.
"I've done a little bit of analysis and if the dam is full and it fails, you're getting flooding that's higher than a 500-year event. Depending upon where Barker dam fails — for example, on the north end — it's not going into Buffalo Bayou, it's going over land and maybe into White Oak." According to Dunbar, the Corps hasn't addressed the over-the-top spillage scenario.
While the Corps is scrambling to ink a deal so that they can start repairing Addicks and Barker dams, work is in progress to shore up Kentucky's Wolf Creek and Tennessee's Center Hill dams, which protect Nashville from Cumberland Lake's pent-up water. When it's complete, the project, which will help protect the Music City against a 200-mile flood, will cost an estimated $584 million. At press time, the Corps hadn't determined estimated repair costs to Addicks and Barker.
Along with filling the voids, Dunbar says that more needs to be done to prevent additional water from making its way to Addicks and Barker. One option would be to direct overflow to Cypress Creek, but that probably wouldn't work because the creek is plagued with its own flooding issues.
Instead, Dunbar says, "The best thing to do is to get more capacity within the reservoir and don't let more development occur upstream that would send more water to the watershed. Then let the water be retained in the Katy Prairie west of the Grand Parkway — you can almost use the Grand Parkway as a dam — and let it sit there and not let it get into the reservoir quickly."
While Dunbar thinks that the Army Corps of Engineers is definitely addressing the complex situation from an engineering standpoint, he has an issue with the Corps' hush-hush strategy.
"I hear that the dams are not at risk of imminent failure and to an extent, I agree. 'Imminent' meaning it's about to fail. There's no water in the reservoir, so it's not going to fail if there's no water in the reservoir," says Dunbar before last week's storms. "The problem is that they're giving the public a false sense of 'Oh, don't worry, it's not a problem.' Well, it is a problem."
Dunbar explains that the Corps held one public meeting in 2010, but after he reviewed the PowerPoint slides and spoke with some people who attended the confab, he determined that "neither the presentation nor these people recalled the Corps ever talking about the fact that this was at an extremely high risk of failure and what the real problems were. The presentation really was, 'Well, we designated this as Level I, but don't worry about it. We've really done this to get priority in funding to do repairs, and everything is fine and dandy.'"
That doesn't sit well with attorney Mary Carter, who is counseling Blackburn on Sierra Club v. U.S. Army Corps of Engineers. She also happens to live on the edge of the flood plain in the Memorial Glen subdivision. "The Corps and Harris County Flood Control have assured that people are safe. I certainly hope that's good information."
Meanwhile, West Houston resident Rosencranz, one of the select few who are hip to the potential dangers, says that Houston might not ever recover if the dams failed. "It's a lot like the lower Ninth Ward levee — as long as it doesn't break, everything is fine, but if it breaks, you have a major issue."
He also says that he shouldn't have to consider moving to higher ground. "Part of the solution isn't to move out of the area; it's something that the Corps of Engineers should deal with," says Rosencranz. "Pretty much all of West Houston and downtown is in that flood plain. Where would you move? Beaumont?"
In fall 2009, the U.S. Army Corps of Engineers tagged West Houston's Addicks and Barker dams with an "extremely high risk of catastrophic failure" label. According to the Corps, the 1940s-era dams, which leaked in April 2009, are two of the country's six most dangerous. As a result, the Corps, during an abnormal weather event, might be forced to release more rainwater downstream, which could send Buffalo Bayou out of its banks and flood homes in Memorial and Tanglewood.
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