The Science of Disasters
EAS 201 – Written Assignment 5
1. What is the difference between a flash flood and a regional flood? Are the causes the same? Are the effects the same?
Flash Flood; are walls of water, set up in a matter of hours by a large convective storm. Many automobile related deaths in a flash flood are in 2 feet of water due to the buoyant lift and current of the water.
In 1997, in Antelope Canyon a flash flood took 12 hikers, tumbling them down the canyon as helpless on lookers could only watch. A wall of water builds due to steep topography, channeling the water and striking a particular area in a thunderstorm.
In Big Thompson Canyon, Colorado in 1976, a ...view middle of the document...
A regional flood occurs over a prolonged rainfall lasting several days or intense rainfall over a short period of time. A regional flood can be the result of ice or debris jam causing a river or stream to overflow. Melting snow can combine with rain in the winter and early spring, a severe thunderstorm can bring heavy rain or tropical cyclone can bring intense rainfall to the coastal and inland states. Where as a flash flood can occur within six hours of rainfall, after a dam or levee failure, following a sudden release of water held by ice or a debris jam. Flash floods can catch people unprepared. There is not always a warning to these deadly floods.
The effects of a flood are much more devastating, as they are intense rains within a very short period of time with little to no warning. A regional flood can be seen on radar and forecasted with time for preparation.
2. Will we be able to control the Mississippi River in the future? Evaluate the possibilities and potential problems. Discuss the effectiveness of some of our most common mitigation techniques, for example, levees and dams.
According to many sources, the Mississippi is an ecological treasure and an economic powerhouse, providing clean water and navigation. I believe the corps of engineers will try their best to control the river for as long as possible. However, as we’ve seen throughout our text, we can’t expect to control natural forces. The Mississippi is a very powerful natural source. The constant drudging to remove sediment and channeling will never change the instability of the river.
As sediment is deposited from its adjoining river systems, raising the riverbed floor, bringing the water over the levees and dams. In the lowest portion of the river, the average water flow is 645,000ft3/sec. We see evidence of levee and dam failure dating back to 1882, killing hundreds if not thousands of people since the commencement of mitigation.
When the levees and dams failed in 1973, the Mississippi flooded ten states. In 1993, the flooding of the Mississippi caused record flooding in 9 states, killing 48 people, submerging 75 towns, destroying 50,000 homes, closing 12 commercial airports and four interstate highways.
This ecological treasure and economic powerhouse is costing the US taxpayers a lot of money! Total cost for damages in 1993 alone was 12 billion dollars. The problem is human interaction is obstructing natures natural course. As evidenced throughout our course material, human interaction regularly causes more damage in dollars and to the environment than actually helping. The river grows as it ages, if the river had been left alone in the 1700 and 1800’s it would have cut its new path and dug its new riverbeds. With our current condition of controlling the Mississippi, more homeowners have moved closer to the river, relying on the dams and levees. As populations grow, we can only expect the damages from future failures to increase the death toll and cost...