Natural hazard and disasters - floods - Assignment Example

Download file to see previous pages Floods are very devastating natural phenomenon. It is a temporary condition wherein dry lands are swamped with waters coming from the outflow of rivers, tidal waters, or from the unusual rapid accumulation of water from any source. Types of floods are riverine floods, flash flooding, storm surge, and dam failure. Riverine floods are caused by heavy rainfall when catch basins are no longer able to hold excess water. Storm surge in coastal areas due to a tidal wave, high tide, tsunami or hurricane. Dam failures are explosion of dams due to earthquake that cause great floods in down streams. Another kind of flood and most common is the “flash floods” that can occur almost anywhere when there is a sudden burst of intense rainfall wherein drainage is either clogged or it has not enough capacity to absorb. Usually, flash floods stay only for short hours. It is unlike river flooding that occurs in low-lying areas adjacent to river and streams that stays flooded for several days.(Geoscience Australia, August 2013.) 2. Explain the system used to classify floods. Several systems of floods classifications have been suggested by engineers and scientists, but I have not found a universal application that is appropriate for a region. For instance, Luke Howard Classification System (n.d.), depends on clouds classification. Accordingly, his system has been used for many years. For Luke, the appearance of clouds formation dictates the amount of rainfall. But to me, this is not the systematic way of classifying floods. Experts today have arrived at a more methodological manner of classifying floods. The National Geographic (2013) said hydrologists used past flood patterns to predict when and where floods could happen, but since these are only estimates, climate , weather, and land can change. Soil scientists study how much water the soil can absorb. The type of soil and the amount of groundwater tells the hydrologist how much more water the earth can absorb. They also determine the amount of water a runoff can absorb. Runoff water comes from natural processes such as excess irrigation, industrial wastes and sewage. Hydrologists also evaluate snowfall and snowpack. Snowfalls are also said to be contributory to flooding, and when snow melts, the grounds may not be able to absorb too much water (National Geographic 2013). Today, our weather stations use modern technology such as Doppler radar. This system helps meteorologist predict floods, it also shows them how severe a storm would be. Doppler system allows scientists to detect weather pattern and to create computerized images of rainfall. There are also automated gauges placed in rivers that measure the height and speed of river currents, and the amount of rainfall received. Scientists also designed a geographic information system that helps them to warn people if the river will overrun its banks and floods are expected. 2. Discuss the 1913 flood which occurred in Dayton, Ohio with regards to: a. The nature of the event. The Great flood in Miami in 1913 has been described as the worst flood ever experienced in the region. A large amount of rainfall that fell continuously in three days, coupled by snow melting winter produced a run-off of streams in the Miami River and other rivers to overflow. These run-offs caused every city along the river to be inundated with floodwaters . b. Issues directly related to the impact of the event . According to the report of Miami Conservancy District, “more than 360 people lost their lives and property damage exceeded $100 million (that’s more than $2 billion in today’s economy). The amount of water that passed through the river channel in Dayton equaled the amount of water that flows over Niagara Falls in a four-day period” (MCD, 2009)  . c. Lessons learned and actions taken as a result of the event. People were really unprepared for this tragedy so that the citizens of Miami, came together to make plans to prevent ...Download file to see next pagesRead More