Lecture 6 Flooding Flashcards
what is runoff
orecipitation that des ni infiltrate and flows along the surface
what is a drainage basin
surroudning areas drained by that river or lake
what is a divide
boudnries of drainage basins, higher land seperates which way rivers flow
what is the continential divide
rocky mountains, separates which ocean water will enevtually drain into
what is the river gradient
longintidual profile (slope) / length of river
what are the materials transported by rivers
bed load: materials that roll or slide along the bottom (rocks pebbles)
suspended load: slit or clay particles
dissolved load: chemicals
what is the dishcarge
the colume of water flowing past a psnt in the river over a specifed period of time
discharge (q) = velocity (v) / area (a)
what are the channel patterns
braided: lacks vegetation, melting glaciers, shallow
anastomosing: two or more channels supports vegetation
meandering: bends, mau avulse creating an oxbow lake
waht detmerined the magnitude and duration of a flood
precipitation in the drainage basin rate at whihc precipitation inflintres the soil presence of snowpack amount of moisture already in the soil speed of runoff ice jams in winter
what is a stage and flood stafe
stage: the level of the river surace at a certain point in time
flood stage: the level of river must reach in order of it to cause property damage
describe upstream floods and downstream floods
upstream: heavy rainfall of short duration over a relatively small area
downstream floods; rain of long duration or rapid melting of snowpack
what is the red river
g
what are the links to other hazards
hurricanes are a major cuase of flooding, landlisdes and colanic eruptions are capable of producing floods, flooding causes erosion leading to landslides, flooding can cause fires
what are the nautral service function
floodplains are very fertile because of periodic deposits of nutrients by flooding good for argiculture, floods flush out debris from channles this having a postive effect of aqua ecosystmes, sustain wetlands by adding sediment
what are the human interactions
dam constriuction channel get eroded, unraization storm sewers decrease the lag time between heavy rain and flooding
