Flooding How does flooding relate to weathering, erosion, and deposition?

Floods A natural event or occurrence where a piece of land (or area) that is usually dry land, suddenly gets submerged under water. Can occur suddenly and recede quickly. Can take days or months to build and discharge. Water flows from high areas to low areas.

Causes Rains – more rain than drainage system can take River overflow – more water upstream flows and fills low-lying areas (floodplain) Strong winds in costal areas – water moved inland by hurricanes or tsunamis Dam breaking – too much water held in the dam Ice and snow-melts – cold areas where heavy layers of snow melt suddenly

What are the short term effects of a flood? What are the long term effects of a flood?

Types Flash Floods Rapid on-set floods Slow on-set floods

Flash Floods Occurs within a short time (2-6 hours) Usually due to heavy rain, dam breaking, or snow-melt Most destructive Usually no warning, no preparation can be made

Utah Flash Flood kgMw kgMw

Rapid on-set floods Similar to flash flood, but takes slightly longer to develop Can last for a day or 2 Very destructive, but not usually a surprise Generally enough time before to prepare quickly

Slow on-set floods Usually a result of water bodies over flooding their banks Develop slowly Can last for days and weeks Fields and low-lying areas are prone to flooding Effects of this type of flood tend to be disease, malnutrition, or snakebites

Flooding Areas Any low-lying area is more likely to flood Areas close to a river, lagoon, or lake Costal areas, and shorelines

Effects of Flooding Economy – roads, bridges, farms, houses, and automobiles are destroyed Environment – chemicals and other hazardous substances get into water sources; kills animals and destroys habitats People and animals – many may be injured or die, diseases and infection come after the flood

Roadways are damaged

Houses are destroyed

Farmlands are devastated

Wimberley, Texas (May, 2015)

Myrtle Beach (October, 2015)

This combination of Aug. 30, 2005 and July 29, 2015 aerial photos shows downtown New Orleans and the Superdome flooded by Hurricane Katrina and the same area a decade later.

Hurricane Ike

Prevention Sea/Costal Defense Walls – prevent tidal waves from pushing the water too far inland Retaining Walls – hold extra water during times of flooding (levees, dams, reservoirs) Town Planning – don’t block waterways Vegetation – help protect against erosion Education – know what you can do to minimize the damages of flooding Detention Basin – temporary storage for floodwaters

Buffalo Bayou Park Houston flooding this past May 4fA9c

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