GEOL 2207 Lecture : Flood styles and causes.docx
Document Summary
Flood styles and causes: downstream or regional floods. Characterized by large slow rise and fall of discharge at particular location. Causes: storms of long duration, periods of intense snowmelt, cumulative effect of flooding in tributaries. Missouri & mississippi rivers, 1993: ~50 fatalities, 50,000 homes damaged/destroyed, billion in damage, lasted 6 months, started off with snowmelt, then wet spring and summer made it worst, levee system constrained flood water. Levees break, water stuck behind the levees. Primary damage: (during the flood: injury and loss of life, structural damage (currents, debris, sediment, erosion and deposition of sediment. Secondary damage: pollution, hunger and disease, displacement and dislocation. Flooding: impacts of flooding (a lot of primary impacts) Dykes: can provide false sense of security. Depth and velocity of floodwaters: are they strong enough to be eroding things and cause mechanical damage, how far the flood will go. Rate of rise and duration: if water rise slowly, people have time to move away.
