If you live in DFW, this is a pretty scary scenario. The Lake Lewisville Dam has spots that are failing. The Corp of Engineers has been downplaying the risk in the media. The impact of a breach would be enormous....greater than the impact Katrina had on New Orleans. Downtown Dallas would be 50 feet underwater.
The full article is a good read......
http://www.dentonrc.com/local-news/...lly-unstable.ece?ssimg=2575991#ssStory2576002
This is an excerpt:
"It is currently ranked as Dam Safety Action Class 2, with “very high” risk and “failure initiation foreseen.” But the Corps is weighing whether to raise this to Class 1, the category for dams that are “extremely high” risk and “critically near failure” and require immediate action to avoid catastrophe.
431,000 in harm’s way
For the last four years, while Vazquez served as the district’s dam safety program manager, avoiding catastrophe at the Lewisville Dam has been at the forefront of his mind. He studied the inundation maps and consequence data for all the district’s dams. If they failed, where would the water go? How many people would be flooded out? How many killed?
When he looked at the data for a breach at the Lewisville Dam, he couldn’t believe his eyes. It showed 431,000 people in harm’s way. The corps has prepared maps of the inundation area and casualty estimates but won’t release them to the public on orders from the U.S. Department of Homeland Security.
The corps also will not release a list of its top 10 high-hazard dams in the country because it might “open the public to security risks from those that could use the information to do harm,” according to a spokesman.
Standing atop the crest of the Lewisville Dam last February, his eyes fixed on the Dallas skyline, Vazquez grew silent as he thought about the catastrophic consequences of a breach. “I think about it a lot,” he says.
With a full reservoir behind it, a 65-foot-tall flood wave traveling 34 mph would quickly inundate a wide swath of Lewisville, Coppell, Carrollton, Farmers Branch, Irving, Las Colinas and other communities bordering the Trinity River.
The wave would sweep everything in its path — the Lewisville dump, water treatment plants, LBJ Freeway, the Bush Turnpike, Interstate 35E, the State Highway 121 Tollway, Love Field, the Hospital District, office complexes, senior citizen centers, shelters, schools, playgrounds and 53,000 other structures.
Like a tsunami, the wave would submerge downtown Dallas in roughly 50 feet of water, the corps estimates, causing more than $21 billion in property damage, before continuing south down the Trinity River toward the Gulf of Mexico. “It would be a much bigger magnitude to the Dallas area than Hurricane Katrina was to New Orleans,” says Vazquez. “It’s a nightmare scenario.”
Dhruv Pandya, assistant director in charge of the city of Dallas’ flood control system, peers at a photograph of the lake’s inundation area that he keeps atop his desk as a reminder of what would happen if the dam breached. “That keeps me on my toes all the time,” he says, pointing to the apocalyptic image.
A few years ago, Pandya says, Dallas set up a contingency Emergency Operations Center outside of downtown Dallas because its current center would be underwater if the dam breached.
The corps has not been idle, either. Over the last several years, it has implemented what it calls “interim risk reduction measures” to stave off a dam failure at Lewisville while at the same time preparing for the worst.
For example, the corps has drilled about 10 new relief wells in Seepage Area No. 1 to relieve pressure and prevent further piping under the dam. The new wells supplement dozens of wells and seepage collection systems already on site.
The federal agency has also stepped up emergency training exercises with officials downstream and urged them to set up an early warning system to alert residents if the dam begins to fail. It’s also built up its stockpiles of sandbags, pumps and other emergency materials to prevent a small-scale breach from mushrooming into a catastrophic one."
The full article is a good read......
http://www.dentonrc.com/local-news/...lly-unstable.ece?ssimg=2575991#ssStory2576002
This is an excerpt:
"It is currently ranked as Dam Safety Action Class 2, with “very high” risk and “failure initiation foreseen.” But the Corps is weighing whether to raise this to Class 1, the category for dams that are “extremely high” risk and “critically near failure” and require immediate action to avoid catastrophe.
431,000 in harm’s way
For the last four years, while Vazquez served as the district’s dam safety program manager, avoiding catastrophe at the Lewisville Dam has been at the forefront of his mind. He studied the inundation maps and consequence data for all the district’s dams. If they failed, where would the water go? How many people would be flooded out? How many killed?
When he looked at the data for a breach at the Lewisville Dam, he couldn’t believe his eyes. It showed 431,000 people in harm’s way. The corps has prepared maps of the inundation area and casualty estimates but won’t release them to the public on orders from the U.S. Department of Homeland Security.
The corps also will not release a list of its top 10 high-hazard dams in the country because it might “open the public to security risks from those that could use the information to do harm,” according to a spokesman.
Standing atop the crest of the Lewisville Dam last February, his eyes fixed on the Dallas skyline, Vazquez grew silent as he thought about the catastrophic consequences of a breach. “I think about it a lot,” he says.
With a full reservoir behind it, a 65-foot-tall flood wave traveling 34 mph would quickly inundate a wide swath of Lewisville, Coppell, Carrollton, Farmers Branch, Irving, Las Colinas and other communities bordering the Trinity River.
The wave would sweep everything in its path — the Lewisville dump, water treatment plants, LBJ Freeway, the Bush Turnpike, Interstate 35E, the State Highway 121 Tollway, Love Field, the Hospital District, office complexes, senior citizen centers, shelters, schools, playgrounds and 53,000 other structures.
Like a tsunami, the wave would submerge downtown Dallas in roughly 50 feet of water, the corps estimates, causing more than $21 billion in property damage, before continuing south down the Trinity River toward the Gulf of Mexico. “It would be a much bigger magnitude to the Dallas area than Hurricane Katrina was to New Orleans,” says Vazquez. “It’s a nightmare scenario.”
Dhruv Pandya, assistant director in charge of the city of Dallas’ flood control system, peers at a photograph of the lake’s inundation area that he keeps atop his desk as a reminder of what would happen if the dam breached. “That keeps me on my toes all the time,” he says, pointing to the apocalyptic image.
A few years ago, Pandya says, Dallas set up a contingency Emergency Operations Center outside of downtown Dallas because its current center would be underwater if the dam breached.
The corps has not been idle, either. Over the last several years, it has implemented what it calls “interim risk reduction measures” to stave off a dam failure at Lewisville while at the same time preparing for the worst.
For example, the corps has drilled about 10 new relief wells in Seepage Area No. 1 to relieve pressure and prevent further piping under the dam. The new wells supplement dozens of wells and seepage collection systems already on site.
The federal agency has also stepped up emergency training exercises with officials downstream and urged them to set up an early warning system to alert residents if the dam begins to fail. It’s also built up its stockpiles of sandbags, pumps and other emergency materials to prevent a small-scale breach from mushrooming into a catastrophic one."
