New Orleans' Hurricane Katrina Hurricane Term Paper
- Length: 15 pages
- Subject: Weather
- Type: Term Paper
- Paper: #75945030
Excerpt from Term Paper :
Folkman, MI. California Engineer Sees Fears About New Orleans Levee system Come True, 2005
The author writes about the thoughts and experiences of Robert Bea, civil engineer at the University of California in Berkeley on the recent killer hurricane in New Orleans. Bea studied the city's levee system since 1954 when began working for the U.S. Army Corps of Engineers, He discovered that it was not high enough and that parts of the city were far below sea level. Fixing the levee system permanently could be a multi-year and multi-dollar effort. The Corps of Engineer reported that major breaches of the levees at the 17th Street and London Canals had been sealed and that water was being pumped out of the city. It, however, said that the entire system was designed to contain only up to Category 3 of a fast-moving hurricane. When Katrina reached land, it was a strong Category 4 disaster and the conditions exceeded the design of the levees system.
Behar, M. Hurricanes, 2005
The author writes that the Saffir-Simpson hurricane scale defines a Category 5 storm as one with "winds greater than 155 miles per hour" and with a surge greater than 18 feet. It was assumed that one such storm was likely to occur only once in every 500 to 1,000 years, and if one did, its surge would swell, overtop the levees and put the city under water up to 40 feet. When it would occur, the levees would serve only as a bathtub, the author quotes chief coastal engineer Harley Winer of the Army Corps at the New Orleans District. Winer then thought that the water getting trapped between the Mississippi levees and the hurricane-protection levees as highly improbable, though possible.
This paper used the descriptive-normative research method in recording, describing, interpreting and analyzing information from various authoritative sources, such as books, reports, news and journal articles and professional accounts.
Damaging winds are the primary concern with any hurricane, but the people of New Orleans know that their biggest threat is water (Galle 2005). They actually live in a bowl or underwater, according to Director Frank Hijuelos of the New Orleans Office of Emergency Preparedness. The city is 6 feet below sea level. A complex series of levees built between the city and the Gulf (Folkman 2005). South of the city is the Mississippi River and Lake Pontchartrain in the North. The Gulf is 100 miles to New Orleans and covers 630 square miles yet is only 25 feet deep. This shallowness is precisely the greatest threat to the city during a hurricane. The formal levee system was established in 1890 along with the Orleans Levee District. To begin with, levees are not permanent structures and not as strong as earthen dams. They are also not engineered to sustain flood pressure beyond a few days. Most other levees in the U.S. were also fortified after the Mississippi River flood in 1927. But those along the northern edge warding off the waves of Lake Pontchartrain were unlike other levees, which were built by the federal Army Corps of Engineers according to high standards and made quite strong. In comparison, those built around the Lake were privately or locally built without the same or similar degree of engineering. Only 17 of the 79 levees that were breached by the Mississippi River flood were federally constructed. The federal government also said that it was unlikely for floodwaters to overtop these levees because they usually seep underneath the river and then appear on the land slide. Severe pressure sometimes leads to "sand boils," the soil within the levee liquefies and structural failure occurs. It, however, admitted that improvements on these levees were done only on piece meal basis because these were expensive. Instead, designs were made to reinforce and prevent the backflow of water into the city during heavy storms (Folkman 2005, Handwerk 2005). It has been reported, though, that reinforcements were built in only one of the three major drainage canals.
There have been lessons to learn from. The levee system already proved ineffective in warding off waves from Lake Pontchartrain as can be gleaned from the consequences of Hurricane Georges in 1998 and Hurricane Betsy in 1965 (Folkman 2005, Handwerk 2005). The natural location, the insufficient height of the levees, their design and the discontinuation of funding are significant issues to address, not only on account of the aftermath of Hurricane Katrina, but also in view of succeeding hurricanes of the same or similar intensities to which the city has become prone. According to civil engineer Robert Bea of the University of California at Berkeley (Folkman 2005), New Orleans used to be a flat, sea-level marshland when early settlers found it. In order to inhabit it, they filled the marshland with sand and drew water from underground. As a result, the ground subsided and parts of it eventually sank.
In time, low-level levees were put up to keep the waters of the Lake and the Mississippi River off the city (Carrn and McKay 2005). In the 50s, New Orleans prospered and became a major seaport. Big channels were set up to allow ships to enter the port from the Gulf of Mexico. Civil engineer from the University of California in Berkeley Robert Bea said new Orleans was bordered by water in all sides and that the electric and gas pump systems for collecting water stood below sea level. This made the systems useless during floods. Bea recounted his experience when Hurricane Betsy stormed the city in the 60s. Many lost their homes and even their lives and damage to the Gulf Coast reached to billions of dollars. Yet this destruction from Hurricane Betsy would not compare with the aftermath of Hurricane Katrina's wrath at Category 5.
New Orleans' extensive levee system was designed to contain only up to Category 3 storm (Carrn and McKay 2005). When Hurricane Katrina raged into the city, the water levels in Lake Pontchartrain at the north border went up and the two levees in the south section yielded under the strain and siege. The ferocious storm pushed the Lake's waves into the heart of the city, demonstrating what experts described as a catastrophic failure of this formal levee system. The U.S. Federal Emergency Management Agency considers a direct and powerful hurricane surge against New Orleans as one of the biggest threats confronted by the nation along with terror attacks and earthquakes. Experts warned that a Category 4 or 5 hurricane would crush many more famous levees in New Orleans. They predicted that the city would drown.
Hurricane Katrina reached land near New Orleans in Louisiana last August 29 and its storm surge razed the levees protecting the city from the Lake (Carrn and McKay 2005). Waters poured into and flooded most of the city. Recent estimate of the damage exceeded $200 billion, surpassing that of Hurricane Andrew as the most expensive natural disaster in U.S. history. The damage spanned the coastal regions of Louisiana, Mississippi and Alabama with hundreds dead and more than a million people displaced. The scale of destruction also attained an unprecedented scale in the U.S. since the San Francisco earthquake in 1906. Mayor Ray Nagin ordered mandatory evacuation before the hurricane struck on August 28 and the order was repeated three days later. The following month, people were told to move to neighboring states. A spread of 90,000 square miles was declared a disaster area and, when it departed, Hurricane Katrina smashed power lines and plunged about five million people into darkness. Homeland Security Secretary Michael Chertoff described the destruction brought about by Hurricane Katrina as "probably the worst catastrophe" to occur in the country's history (Carrn and McKay).
The U.S. Army Corps of Engineers said that it had sealed the major breaches on 17th Street and London Canals and had begun pumping water out of the city (Carrn and McKay 2005). It, however, also warned that the entire levee system had become untenable. It emphasized that the walls and levees were designed to contain a fast-moving Category 3 Hurricane only and Katrina grew into a strong Category 4 when it reached land. Accompanying conditions surpassed the design and its capabilities. Natural and human factors affect the coast. Delta soils by nature compact and sink in time, giving way to open water, except when fresh layers of sediments are placed to offset them. The Mississippi spring floods previously retained that balance, but yearly deluges were often destructive. The strong flood 1927 erased the levees, lined with concrete and funneled marsh-building sediments to the deep waters of the Gulf. Engineers also severed more than 8,000 miles of canals through the marsh for petroleum exploration and ship traffic (Bourne 2005). These new ditches increased the…