Water Use and Resource Problems Fall into Three Categories -Too much water -Too little water -Poor quality/contamination
Water Use and Resource Problems • Fall into Three Categories – Too much water – Too little water – Poor quality/contamination
Too Much Water ·Flooding -Both natural and human-induced Modern floods are highly destructive because humans: -Remove water-absorbing plant cover from soil Construct buildings on floodplains 。Floodplain -Area bordering a river channel that has the potential to flood
Too Much Water • Flooding – Both natural and human-induced • Modern floods are highly destructive because humans: – Remove water-absorbing plant cover from soil – Construct buildings on floodplains • Floodplain – Area bordering a river channel that has the potential to flood
Too Much Water:Floods Natural phenomena Aggravated by human activities Rain on snow Living on floodplains Impervious surfaces (floods in Beijing) Removal of vegetation Draining wetlands Reservoir Dam Levee Flood wall Floodplain @2002 Brooks/Cole-Thomson Learning
Too Much Water: Floods • Natural phenomena • Aggravated by human activities • Rain on snow Living on floodplains • Impervious surfaces (floods in Beijing) • Removal of vegetation • Draining wetlands Floodplain Levee Flood wall Dam Reservoir
Flood plain Left:Traditional levees adjacent to river Higher levee adjacent to river Channelized river Flood plain Right: Suggested levee style,set back from river Smaller levee set Natural river back on flood plain with meanders
Left: Traditional levees adjacent to river Right: Suggested levee style, set back from river
Urban vs.Pre-Urban Floodplains Evaporation and Precipitation Precipitation Evaporation and transpiration 100% 100% transpiration 40% 25% Surface runoff 43% Surface runoff(includes storm sewer runoff from roads and buildings) Groundwater 50% 32% Groundwater Pre-urban Urban
Urban vs. Pre-Urban Floodplains