Post by bamaguy on Sept 10, 2005 17:43:33 GMT -5
I was doing a little bit of research today whe I came across this article on the Civil Engineering Website.
www.pubs.asce.org/ceonline/ceonline03/0603feat.html
---quote---"If a storm of category 4 or 5 were to hit New Orleans before the city was adequately prepared, what toll would it exact?
In the 1980s Joseph Suhayda, then a coastal oceanographer in the civil engineering department at Louisiana State University (LSU), began to seek an answer to this question by simulating storms with a modified version of a hurricane model used by the Federal Emergency Management Agency (FEMA). Suhayda first began modeling the storms to help parishes in southeastern Louisiana determine appropriate flood elevations for FEMA’s National Flood Insurance Program. As his modeling capabilities improved, he began to more closely investigate the level of protection provided by the levees encircling New Orleans.
Suhayda’s model contains a geographic information system overlay that divides a fairly large boundary, from Alabama to Texas, into 0.6 mi (1 km) grids containing information about ground elevations, land masses, and waterways. The FEMA hurricane model does not draw on the same processing power as AdCirc and in general produces more liberal projections of flooding from storm surges. But by solving numerical equations representing a storm’s pressure, wind forces, and forward velocity, Suhayda was able to use the model to predict the storm surge associated with an actual hurricane dozens of hours before it hit land. By subtracting the elevations on a topographical map of coastal Louisiana from those surge values, he was able to approximate the flood risk of a given storm.
In the 1990s, Suhayda began modeling category 4 and 5 storms hitting New Orleans from a variety of directions. His results were frightening enough that he shared them with emergency preparedness officials throughout Louisiana. If such a severe storm were to hit the city from the southwest, for instance, Suhayda’s data indicate that the water level of Lake Pontchartrain would rise by as much as 12 ft (3.7 m). As the storm’s counterclockwise winds battered the levees on the northern shore of the city, the water would easily top the embankments and fill the streets to a depth of 25 ft (7.6 m) or more.
Suhayda’s model is not the only one that describes such a catastrophe. A model called SLOSH (Sea, Lake, and Overland Surges from Hurricanes), which is used by the National Weather Service and local agencies concerned with emergency preparedness, portrays an equally grim outcome should a storm of category 5 hit New Orleans. The SLOSH model does not contain nearly as many computational nodes as does AdCirc, it does not use a finite-element grid to increase the resolution of the nodes on shore, and its boundary is much smaller. Even so, its results are disheartening.
“Suppose it’s wrong,” says Combe, the Corps modeler. “Suppose twenty-five feet is only fifteen feet. Fifteen feet still floods the whole city up to the height of the levees.”
Experts say a flood of this magnitude would probably shut down the city’s power plants and water and sewage treatment plants and might even take out its drainage system. The workhorse pumps would be clogged with debris, and the levees would suddenly be working to keep water in the city. Survivors of the storm—humans and animals alike—would be sharing space on the crests of levees until the Corps could dynamite holes in the structures to drain the area. In such a scenario, the American Red Cross estimates that between 25,000 and 100,000 people would die.
That prospect—and the amount of time it would take the Corps to construct adequate levee protection against a storm of category 4—have inspired Suhayda to push for what he calls a community haven project. His idea is for the city to construct a 30 ft (9 m) tall wall equipped with floodgates through the center of town to protect the heart of New Orleans and such culturally important areas as the French Quarter. That portion of the city lies between two bends in the Mississippi River and is therefore already protected by adequate levees on three sides. With its gates closed, the wall would complete a waterproof ring around the area.
Suhayda says the wall would be cheaper and faster to build than the larger projects under consideration by the Corps. It could be constructed along an existing right-of-way and act as a sound wall most of time. “We’re going to build sound barriers along most of these roads anyway,” Suhayda says. “So for a small added cost, go ahead and make them capable of withstanding wind loads and hydrostatic heads.”
The Corps would not necessarily be involved in the construction of such a wall because the latter would be land based. Even so, Naomi is adamantly opposed to the idea. “How do you protect people from two-hundred-mile-per-hour winds?” he asks. “Where do they go? What buildings are designed to withstand that? Where do they get their power and their food, and where do they rest their heads at night? Just keeping the water out isn’t enough. You don’t want to give people a false sense of security by saying that this is a refuge unless you have a place for them to go.”
For the most part, New Orleans does not have places for people to go. The American Red Cross no longer provides emergency shelters in the city because its officials cannot guarantee the structural integrity of the locations. There simply are not enough buildings in the area that could withstand the forces of a category 4 or 5 storm.
During the past 10 years Marc Levitan, a wind and structural engineer and the director of LSU’s Hurricane Center, has been involved in hundreds of building investigations throughout New Orleans to determine if certain structures could be used as so-called refuges of last resort. “With the vast majority of them, if you really do an analysis, you really wouldn’t want to use them,” he says. “They all have some sort of deficiency.”
Most people would not wish to remain in the city if a category 4 or 5 storm were in prospect, but evacuating could be difficult. Experts say close to 400,000 people could be stranded in the city. There are an estimated 100,000 people without easy access to automobiles, and those who can drive may not be able to do so. During Hurricane Andrew, interstates throughout the South were brought to a standstill because simultaneous evacuations were taking place in several states. The only major planning improvement since then has been the decision to keep traffic away from the coast on both sides of evacuation routes.
Complicating the difficulty in New Orleans is the fact that each of the city’s three major evacuation routes is over or near water. Suhayda’s model indicates that during a storm of category 5 Interstate 10, which is constructed on piers for a distance of almost 20 mi (32 km) west of the city, could be covered by more than 5 ft (1.5 m) of water.
ater has literally made New Orleans what it is today. Some locals call southern Louisiana the re–United States because in essence the ground is made up of sediment from throughout North America that has made its way down the basin of the Mississippi. The decision to live in this place, however, has also made water the enemy. "---end quote----
While I am in no way in attack mode WANTING to point fingers (it might seem like this) but I am wanting to "Maybe" educate people to the fact that there is ADEQUATE blame on many fronts and at many locales. The Federal government should be blamed, the City of NEw Orleans officials should be blamed, the Government of Louisiana should be blamed. Some of you might think I defend Presidnet Bush, and I do in some sense, however Bush is only 1 person in this long chain of bureacrats. I have seen a Pointedly POLITICAL Attack towards our current president Bush. IMHO it is unwarranted. Some are suggesting Race had a hand in this federal effort, that is so untrue. Liberla persuasive people have seen an oppertunity to castigate President Bushm this is so sad and also unwarranted.
Back to my find of this article. Read it it will OPEN your eyes to the very SERIOUS Problems that new Orleans faces. In essence this city of NEw Orleans plays a game of Russian Roulete every Hurricane season. To even suggest that our Federla Government can Engineer some sort of protection from Mother Nature's fury of a very Strong Hurricane category 4-5 is a DELUSION.
Any feedback will be interesting, if only open minds and hearts are brought to the discussion.
Thanx,
BamaGuy from Birmingham
www.pubs.asce.org/ceonline/ceonline03/0603feat.html
---quote---"If a storm of category 4 or 5 were to hit New Orleans before the city was adequately prepared, what toll would it exact?
In the 1980s Joseph Suhayda, then a coastal oceanographer in the civil engineering department at Louisiana State University (LSU), began to seek an answer to this question by simulating storms with a modified version of a hurricane model used by the Federal Emergency Management Agency (FEMA). Suhayda first began modeling the storms to help parishes in southeastern Louisiana determine appropriate flood elevations for FEMA’s National Flood Insurance Program. As his modeling capabilities improved, he began to more closely investigate the level of protection provided by the levees encircling New Orleans.
Suhayda’s model contains a geographic information system overlay that divides a fairly large boundary, from Alabama to Texas, into 0.6 mi (1 km) grids containing information about ground elevations, land masses, and waterways. The FEMA hurricane model does not draw on the same processing power as AdCirc and in general produces more liberal projections of flooding from storm surges. But by solving numerical equations representing a storm’s pressure, wind forces, and forward velocity, Suhayda was able to use the model to predict the storm surge associated with an actual hurricane dozens of hours before it hit land. By subtracting the elevations on a topographical map of coastal Louisiana from those surge values, he was able to approximate the flood risk of a given storm.
In the 1990s, Suhayda began modeling category 4 and 5 storms hitting New Orleans from a variety of directions. His results were frightening enough that he shared them with emergency preparedness officials throughout Louisiana. If such a severe storm were to hit the city from the southwest, for instance, Suhayda’s data indicate that the water level of Lake Pontchartrain would rise by as much as 12 ft (3.7 m). As the storm’s counterclockwise winds battered the levees on the northern shore of the city, the water would easily top the embankments and fill the streets to a depth of 25 ft (7.6 m) or more.
Suhayda’s model is not the only one that describes such a catastrophe. A model called SLOSH (Sea, Lake, and Overland Surges from Hurricanes), which is used by the National Weather Service and local agencies concerned with emergency preparedness, portrays an equally grim outcome should a storm of category 5 hit New Orleans. The SLOSH model does not contain nearly as many computational nodes as does AdCirc, it does not use a finite-element grid to increase the resolution of the nodes on shore, and its boundary is much smaller. Even so, its results are disheartening.
“Suppose it’s wrong,” says Combe, the Corps modeler. “Suppose twenty-five feet is only fifteen feet. Fifteen feet still floods the whole city up to the height of the levees.”
Experts say a flood of this magnitude would probably shut down the city’s power plants and water and sewage treatment plants and might even take out its drainage system. The workhorse pumps would be clogged with debris, and the levees would suddenly be working to keep water in the city. Survivors of the storm—humans and animals alike—would be sharing space on the crests of levees until the Corps could dynamite holes in the structures to drain the area. In such a scenario, the American Red Cross estimates that between 25,000 and 100,000 people would die.
That prospect—and the amount of time it would take the Corps to construct adequate levee protection against a storm of category 4—have inspired Suhayda to push for what he calls a community haven project. His idea is for the city to construct a 30 ft (9 m) tall wall equipped with floodgates through the center of town to protect the heart of New Orleans and such culturally important areas as the French Quarter. That portion of the city lies between two bends in the Mississippi River and is therefore already protected by adequate levees on three sides. With its gates closed, the wall would complete a waterproof ring around the area.
Suhayda says the wall would be cheaper and faster to build than the larger projects under consideration by the Corps. It could be constructed along an existing right-of-way and act as a sound wall most of time. “We’re going to build sound barriers along most of these roads anyway,” Suhayda says. “So for a small added cost, go ahead and make them capable of withstanding wind loads and hydrostatic heads.”
The Corps would not necessarily be involved in the construction of such a wall because the latter would be land based. Even so, Naomi is adamantly opposed to the idea. “How do you protect people from two-hundred-mile-per-hour winds?” he asks. “Where do they go? What buildings are designed to withstand that? Where do they get their power and their food, and where do they rest their heads at night? Just keeping the water out isn’t enough. You don’t want to give people a false sense of security by saying that this is a refuge unless you have a place for them to go.”
For the most part, New Orleans does not have places for people to go. The American Red Cross no longer provides emergency shelters in the city because its officials cannot guarantee the structural integrity of the locations. There simply are not enough buildings in the area that could withstand the forces of a category 4 or 5 storm.
During the past 10 years Marc Levitan, a wind and structural engineer and the director of LSU’s Hurricane Center, has been involved in hundreds of building investigations throughout New Orleans to determine if certain structures could be used as so-called refuges of last resort. “With the vast majority of them, if you really do an analysis, you really wouldn’t want to use them,” he says. “They all have some sort of deficiency.”
Most people would not wish to remain in the city if a category 4 or 5 storm were in prospect, but evacuating could be difficult. Experts say close to 400,000 people could be stranded in the city. There are an estimated 100,000 people without easy access to automobiles, and those who can drive may not be able to do so. During Hurricane Andrew, interstates throughout the South were brought to a standstill because simultaneous evacuations were taking place in several states. The only major planning improvement since then has been the decision to keep traffic away from the coast on both sides of evacuation routes.
Complicating the difficulty in New Orleans is the fact that each of the city’s three major evacuation routes is over or near water. Suhayda’s model indicates that during a storm of category 5 Interstate 10, which is constructed on piers for a distance of almost 20 mi (32 km) west of the city, could be covered by more than 5 ft (1.5 m) of water.
ater has literally made New Orleans what it is today. Some locals call southern Louisiana the re–United States because in essence the ground is made up of sediment from throughout North America that has made its way down the basin of the Mississippi. The decision to live in this place, however, has also made water the enemy. "---end quote----
While I am in no way in attack mode WANTING to point fingers (it might seem like this) but I am wanting to "Maybe" educate people to the fact that there is ADEQUATE blame on many fronts and at many locales. The Federal government should be blamed, the City of NEw Orleans officials should be blamed, the Government of Louisiana should be blamed. Some of you might think I defend Presidnet Bush, and I do in some sense, however Bush is only 1 person in this long chain of bureacrats. I have seen a Pointedly POLITICAL Attack towards our current president Bush. IMHO it is unwarranted. Some are suggesting Race had a hand in this federal effort, that is so untrue. Liberla persuasive people have seen an oppertunity to castigate President Bushm this is so sad and also unwarranted.
Back to my find of this article. Read it it will OPEN your eyes to the very SERIOUS Problems that new Orleans faces. In essence this city of NEw Orleans plays a game of Russian Roulete every Hurricane season. To even suggest that our Federla Government can Engineer some sort of protection from Mother Nature's fury of a very Strong Hurricane category 4-5 is a DELUSION.
Any feedback will be interesting, if only open minds and hearts are brought to the discussion.
Thanx,
BamaGuy from Birmingham