Natural Disaster Exam 3

USC Upstate

what is a stream?

water that flows in a channel

what 2 things are surface water?

drainage basins and drainage divides

stream flow changes from ______ to _______

upstream to downstream

what is river discharge (Q)?

volume of water moving past a point on a river over a unit of time

what forms do rivers carry sediment?

suspended load, dissolved load, and bed load

what is the primary erosion agent in the rock cycle?

rivers

the amount of erosion and deposition depends on what?

stream velocity and discharge

stream flow ______ and ____ when moving from high to low gradient

widens and slows

slower water carries less or more sediment?

less

what are floodplains?

areas of flat ground bounding a river channel on either side

what is the discharge equation?

Q=w x d x v

when the discharge goes up, everything goes ____

up

floodplains are ____ in mountains/hills but ____ in low land areas

narrow, wide

a flood is……

more water that can fit in a channel

floods are related to:

amount and distribution of rain, infiltration, runoff velocity, moisture already in the soil, topography, and land use

the steaper the slope, the ______ of the runoff velocity

higher

incredibly dry soil will absorb water _____

slowly

what does impermeable mean?

surfaces that will not soak up water, bigger floods

what does permeable mean?

surfaces that will soak up water, smaller floods

do all rivers flood?

yes

what are floods are measured by?

stream discharge, velocity, and height. and hydrographs

what is lagtime?

when we hit maximum rain fall and maximum flood. also a warning time

recurrence intervals are used as a _______

forecast

recurrence intervals helps with ____ _____ ________

land use planning

100-year flood means what?

there is a 1% probability each year, 1/100