GG231 Chapter Notes - Chapter 9: Big Thompson River, Dynamic Equilibrium, Red River Floodway
Document Summary
Flooding = most universally experienced natural hazard. Killed more than 10,000 ppl in na since 1900. Property damage = billion per year. Water evaporates from earth surface, exists as gas, precipitates on oceans and land, infiltrates the ground and returns to the atmosphere through evaporation and transpiration by plants. Runoff: surface flow finds way to small streams (tributaries of larger streams) or rivers. Drainage basin/watershed/river basin/ catchment: region drained by a single stream: collects rain and snow. Gradient: the slope of the surface over which it flows: determined by calculating the drop in elevation of the channel over some horizontal distance, greatest in its headwaters, lowest at its base level. Lowest elevation to which it may erode (at or near sea level: longitudinal profile = graph showing downstream changes in a river"s elevation. Earth material transported by rivers: total load: water and tremendous amount of material.
