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Floods are an overflow of water that submerges land and usually happen because of a large amount of rainfall, saturated soil, and/or the capacity of the body of water is exceeded:
Often floods are seasonal in nature, coming after Spring rains. (e.g. Katrina)
Floods also occur in rivers, when flow exceeds capacity in certain areas of the river channel.
Floods have impacted society for centuries because people like to live near water and water transportation.
In certain parts of the world, typically those with regular monsoon conditions, flooding is a regular seasonal issue
Suggested graphics: http://www.kidcyber.com.au/IMAGES/Floods4.jpg
Types of Floods -- The flood type depends on the geographic location of the body of water and its tendencies:
Areal flooding happens when flat, low-lying areas cannot absorb any more water
River floods occur when the river cannot carry away all the extra water and the river overflows
Coastal floods are usually caused by harsh weather blowing waves onto land.
Flash Flooding is a quick flood caused by a sudden cloudburst or thunder storm. Often these happen in mountainous areas with steep slopes.
Flooding from Human Action occurs when an artificial structure like a dam fails, or levees or pipes burst or are poorly constructed.
Suggested graphics: http://www.sciencemediacentre.co.nz/wp-content/upload/2011/02/flood.jpg
Flood Causation -- Flood can occur for a number of reasons, which makes them incredibly hard to predict and prepare for, particularly since humans tend to congregate around water.
Water from storms can no longer be absorbed into the soil; either pools or runs to lower elevation.
Heavy snowfall pack in areas followed by strong Spring/Summer rains
Intense precipitation -- thunderstorms, etc. Or release from a landslide or glacier
In estuaries caused by tidal surges from storm-force winds
Tsunami's or hurricanes -- storm surges
Catastrophic from dam breakage, earthquake or volcanic eruption -- also called outburst flooding
Suggested graphics: http://www.cnn.com/video/weather/2011/01/12/vo.sri.lanka.floods.slrc.640x360.jpg
Effects of Flooding, Part 1
Primary effects -- damage to structures, bridges, buildings, sewage system, roadways, canals
Floods have had a major impact on human society for centuries
Floods disrupt society completely; including social structures and economics
Transportation issues affect surrounding areas
People may need to be evacuated and rehoused for a time
Disruption in entire socio-culture template
Suggested graphics: http://news.xinhuanet.com/english/2008-06/15/xin_5020605152044156235937.jpg
Effects of Flooding, Part 2
Secondary effects -- as the water recedes or damage due to pressure, weather, etc.
Secondary effects may last for months, even years
Water supplies -- water may become contaminated
Potable water becomes rare
Spread of waterborne diseases (lack of sanitation, standing water)
Crops and food supplies ruined, sometimes entire harvests
Inadequate disaster planning and evacuation procedures
Suggested graphic - http://cdn.punchng.com/wp-content/uploads/2012/06/Lagos-flood.jpg
Flood Control, Part 1
Humans have been trying to control floods for thousands of years. However, some flooding, particularly along the great river valleys (e.g. Nile) were the reason agricultural activities flourished and civilization developed
There is a balance between the regular flooding of river areas and catastrophic flooding
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Flood Control, Part 2
Dams and reservoirs are designed to aid in flood protection and control. They do this by controlling water levels and allowing water to flow as needed, but to protect lower elevations by storing water behind the dam wall.
River defenses -- Levees, bunds, reservoirs and weirs (low head dam) are all used to prevent rivers from bursting
Coastal defense -- sea walls, barrier islands, tide gates, enhancing beach areas
Suggested graphics: http://t1.gstatic.com/images?q=tbn:ANd9GcR8qfhdv0UvHzxKQsI8D1gJ06Ec72uZAtyhZzjc8VhjQb9k80MQ8z2n0mGv and/or http://crooksandliars.com/files/uploads/2008/06/illinois-levees.jpg
Flood Control, Part 3
Different regions have adapted flood control based on their economic wealth, type and frequency of flooding, and the density of population near flood-prone areas.
Americas -- Usually miles of levees, flood gates, and drainage systems
Asia -- Some building of massive dams, but deforestation…
Sylves, R. Diaster Policy and Politics: Emergency Management and Homeland Security. New York: CQ Press. 2008. Print.
May need to break into two slides
May need to break into two slides
They can also enable countries to become more self-reliant rather than relying on international sources of energy. In these five ways, dams may prove very beneficial to countries utilizing them. Many cities that build dams take advantage of damns as a resource for tourism and revenues. Because dams often pose a majestic view, and provide the opportunity for recreation in the form of boating and camping, many cities use them
Redland Wastewater Treatment Plant Redland Water is the department of the Redland City council that oversees the collection, treatment, and disposal of waste water in Redland City. Residential households and commercial premises such as shopping centers, cafes, commercial laundries, butchers, car-washing centers, and restaurants are the main sources of waste water in Redland City. Once collected, waste water is stored temporarily in abattoirs, before being released for treatment in one of
clarion call for the people and leaders of El Paso to better focus (or at least start focusing) on the subject of soil erosion, water runoff and sedimentary issues relating the land and material around the roads and bridges of our town. While some may treat this subject as relatively or completely unimportant, this could not be further from the truth. As shown by what can happen with things
" The U.S. Army Corps of Engineers is currently at work in the city on a project to increase the height of the levees and construct floodgates, at a cost of over $12 billion. This work will be able to protect from a "100-year" storm as they are called -- dangerous but not severe -- with a 1-in-100 chance of hitting in any given year. It is estimated it will take
For example, the soil in the Loess Plateau area is notoriously erodable and it is difficult to revegetate the steep slopes with a sufficiently dense cover of plantation and grass. Moreover, rainfall in the area is generally insufficient to support the growth of trees and plants even after their plantation; grazing by animals worsens the situation. Silt retention dams and structures in the silt-carrying gullies and valleys have proven
Another consequence of the exploitative use of water resources is the destruction of mangrove forests and the fragmentation of the habitats of endangered species. The United Nations Convention on International Trade in Endangered Species of Wild Flora and Fauna listed 189 endangered species in China among the 740 in the world. Sand content is quite high in the Yellow River. In the dry season, sand rises and flies up with the