4-2. FLOOD Generals Overflow of water that submerges lan d which is usually dry Occurs whenever/wherever the water is supplied more than the drainage capacity (how about sea flooding?) Upstream vs. downstream flooding

Stream (River) The main drainage of the watershed – so critical for the flooding Probably the most significant medium for erosion, transportation & sedimentation on land We are still heavily dependent on streams

Meandering Mississippi River.

Flood Damage Function of Water precipiation Drainage capability Landforms Floodplain usage Population

Flood Effects Primary Loss of life Damages to the properties Loss of the soils Pollution of water Secondary Disease (epidemic) Shortage of supplies (food, water etc) Economic hardship Psychological damage

Human Interference Artificial walls (levee) Channel dredging Dams Discuss “Four Major Rivers Projects”

For the third time in 15 years the Mississippi River massively burst its banks this spring, inundating tiny Missouri towns such as Winfield (population 720) and Foley (population 178), causing potentially billions of dollars' worth of destruction—although the damages are still being assessed—and hiking corn prices to $8.00 a bushel in the wake of the lost crop

Soyang Dam

Flood Damage in Longarone Village A church tower remains standing in the Italian village of Longarone after flood waters from the Vaiont Dam roared through the village, destroying most of it and killing over 2,000 people. October 10, Italy Vaiont Dam Disaster

Flood Forcasting?

Urbanization and Flood

Measures Regulations on floodplain usage Insurance Preparation (of food and other supplies) for emergencies Hazard map

FloodplainTerms.aspx

Deadliest Floods (from Wikipedia “Flood”) Death tollEventLocationDate 2,500,000–3,700, China floodsChina ,000–2,000, Yellow River (Huang He) floodChina ,000–700, Yellow River (Huang He) floodChina ,000 Banqiao Dam failure, result of Typhoon Nina. Appr oximately 86,000 people died from flooding and an other 145,000 died during subsequent disease. China ,000Indian Ocean tsunamiIndonesia , Yangtze river floodChina ,000+St. Felix's Flood, storm surgeNetherlands ,000Hanoi and Red River Delta floodNorth Vietnam , Yangtze river floodChina1911