Earth Science News  





. Engineers Find New Way To Close Levees

Photo courtesy of AFP.
by Staff Writers
Los Angeles (SPX) Aug 28, 2006
A team of University of South Carolina civil engineers who have studied the failure of the 17th Street canal levee in New Orleans say they have found a cost-effective and efficient way to halt flooding caused by breached levees.

The study, done by researchers in USC's College of Engineering and Information Technology, is believed to be the first to look at the hydraulics of the 17th Street canal breach and the closing procedures used in the hours after Hurricane Katrina.

Their research, funded by $25,000 from USC's Office of Research, will continue with a $100,000 grant from the National Science Foundation and could have implications for levees throughout the United States and the world.

Dr. Hanif Chaudhry, chairman of USC's department of civil and environmental engineering, and his colleague, Dr. Ahmed Kassem, a civil-engineering research professor, examined the breach of the New Orleans levee and found that a concept for closing cofferdams - temporary barriers made of wood, steel or concrete that hold back water - may prevent the widespread flooding that results from levee failure.

Like millions of Americans, Chaudhry watched as engineers raced against time to close the breached levee. But he watched with a civil engineer's keen eye.

"It was apparent that the ordinary dumping of sandbags would not work and that a more systematic approach utilizing knowledge and experience gained from the closing of rivers might have been better," said Chaudhry, who has been a consultant on a number of projects for the U.S. Army Corps of Engineers.

The attempts to close the breached levee failed because the velocity of the water flowing through the breach was too high for the size of the sandbags that were used, Chaudhry said.

"Even sandbags that weighed 10,000 pounds washed away," he said. "Our laboratory tests confirm this and show that it would have taken sandbags weighing about 50,000 pounds to stay."

In the hydraulics laboratory, USC's researchers constructed a scale model of the canal, the breach and the surrounding area, which included a number of homes. One foot on the model represents about 50 feet on the levee.

They utilized "similitude relationships" to produce, to scale, the flow velocity, flow rate, and sandbags used in New Orleans to close the breached levee in New Orleans.

Then, using a concept for closing rivers, the USC researchers added stones between the homes to obstruct the water. The houses also acted as barriers to the water.

Although the obstruction didn't stop the flow completely, it backed up water to the breach location, reducing the flow velocity and allowing the use of smaller sandbags. Researchers believe that if the same method had been used in New Orleans, the city's flooding would have been much less.

"By doing this, we were successful in closing the breach with sandbags that weighed about 7,500 pounds," Chaudhry said. "Our next step will be to try closing the breach with sandbags weighing as little as 5,000 pounds or less, but utilizing another concept from river closure". These concepts are cost effective and efficient and have been successfully used for closing large rivers," he said.

"These procedures should help to close breached levees in a shorter time, thereby reducing the extent and depth of flooded areas," Chaudhry said.

USC's levee research could have an impact beyond New Orleans. Levee systems throughout the United States, including those in San Diego, along the Mississippi River and the Congaree River in South Carolina, and throughout the world could be affected by the USC studies.

Chaudhry's first grant for the levee study was one of 18 funded with $400,000 from USC's Office of Research for studies on the societal and environmental implications of Hurricane Katrina. The new NSF grant will enable USC's civil-engineering researchers to expand their research.

"Having this grant will greatly add to our preliminary findings," Chaudhry said. "The flooding caused by Hurricane Katrina will never be forgotten by those who watched it on television and by those who lived through it. We want to prevent this type of disaster from occurring again."

Related Links
Bring Order To A World Of Disasters

ER Hardship In The Big Easy
Washington (UPI) Aug. 23, 2006
Almost one year to the day that Hurricane Katrina pounded New Orleans and the surrounding Gulf region, a new survey of the area's emergency room (ER) physicians paints a grim scene of ERs struggling to treat growing numbers of uninsured patients with sometimes only half the number of beds and staff needed, dangerously long wait times for patients and a dwindling pool of specialists to whom ER patients can be referred.

.
Get Our Free Newsletters Via Email
  



  • Engineers Find New Way To Close Levees
  • ER Hardship In The Big Easy
  • Pakistan Clerics Order Quake Aid Groups To Fire Women
  • Landmark New Orleans Hospital Operates In Department Store

  • Prevention Vital Against Desertification
  • More Carbon Dioxide May Help Some Trees Weather Ice Storms
  • Study Breaks Ice On Ancient Arctic Thaw
  • Deep-Sea Sediments Could Safely Store Man-Made Carbon Dioxide

  • Renewed Volcanic Activity At The Phlegrean Fields Tracked By Envisat
  • China To Launch 1st Environment Monitoring Satellite
  • NG Demonstrates Synthetic Aperture Laser Radar for Tactical Imagery
  • MODIS Images Western Wildfires

  • Researchers Aim To Close "Green Gap" In LED Technology
  • Gulf Oil And Gas Output Trails Pre-Katrina Production
  • Australia To Build 232 Megawatt Wind Farm
  • "Frozen" Natural Gas Discovered At Unexpectedly Shallow Depths Below Seafloor

  • HIV Life Expectancy Now Normal
  • Analysis: Time To Quit On AIDS Vaccine
  • Fear Of Human Spread Of Bird Flu Lessens
  • Analysis: AIDS Research Pipeline Bursting

  • Scientists Uncover Critical Step In DNA Mutation
  • New Definition Of Species Could Aid Species Identificationon
  • Insect Predation Sheds Light On Food Web Recovery After The Dinosaur Extinction
  • Calendrical Bacteria

  • Lebanese Fishermen Crippled By Wartime Oil Spill
  • Giant Ramses Statue Flees Central Cairo Pollution
  • Massive Philippines Oil Spill Raises Health Fears
  • Lebanon Oil Spill Cleanup May Take A Year

  • Premier To Open World-Leading Research Unit
  • No Hobbits In This Shire
  • Is Functional RNA The Missing Link
  • Newly Discovered Gene May Hold Clues To Evolution of Human Brain Capacity

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement