EARTHSC 2GG3 Lecture Notes - Surface Runoff, Flood Warning, Strahler Number
15 Nov 2013
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Document Summary
Some of precipitation in an area percolates through soil to become groundwater and is collected by rivers and streams. Losing streams lose water into the ground. Wet climates: groundwater flows into gaining streams, ensuring year-round flow. Dry climates: water from streams feed groundwater. Losing streams may dry up between rainstorms. Areas of moderate to high annual rainfall: groundwater continuously feeds streams, changes in precipitation result in changes to groundwater levels but stream inflow is generally constant. Semi-arid to arid regions: water from losing streams sinks into ground and streams may dry up between storms, flash floods can occur after any major or prolonged rainfall. Runoff: liquid water that travels over the surface of the earth, moving downward due to gravity. Some precipitation flows as surface runoff during torrential rainfall (rapid runoff is overland flow) Ability of ground to absorb rainwater depends on: rate of precipitation, permeability of soil, extent of prior saturation, whether ground is frozen.
