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

• https://www.youtube.com/watch?v=mHJmfySkgMw

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• https://www.youtube.com/watch?v=wnD3D-

4fA9c

• http://app.discoveryeducation.com/player/view/assetGuid/5FB51B76-B551-464C-BAFE-46A572D2FE50