1. Chapter 21 Water Supply, Use and Management

3. Groundwater and Streams Groundwater –Water found below the Earth’s surface, within the zone of saturation, below the water table –Water table, recharge zones, discharge zones, aquifer, cone of depression Effluent Stream –A type of stream where flow is maintained during the dry season by groundwater seepage into the channel Influent Stream –A type of stream that is everywhere above the groundwater table and flows in direct response to precipitation

6. Water Supply: A U.S. Example Water budget –a model that balances the inputs, outputs and storage of water in a system. –Defines the natural variability and availability of water Over 99% of the Earth’s water is unavailable or unsuitable for beneficial human use It is expected that the total water withdrawn from streams and groundwater in the U.S will decrease but the consumptive use will increase

9. Desalination as a Water Source Desalination: a technology to remove salt from water Increased cost

10. Water Use Off-stream use: –water removed from it’s source for use In-stream use: –the use of rivers for navigation, hydroelectric power generation, fish and wildlife habitats and recreation

15. Water Conservation -the careful use and protection of water resources -Agricultural Use -Domestic Use -Industry and Manufacturing Use -Perception and Water Use

17. Sustainable Water Use The use of water resources by people in a way that allows society to develop and flourish into an indefinite future without degrading the various components of the hydrologic cycle or the ecological systems that depend on it

19. Wetlands Areas that are inundated by water or where the land is saturated to a depth of a few centimeters for at least a few days per year Wetlands serve a variety of functions that benefit ecosystems and people

21. Channelization and the Environment Channelization: –An engineering technique that consists of straightening, deepening, widening, clearing, or lining existing stream channels –Purpose: Control floods, improve drainage, etc.

23. Flooding The most universal natural hazard in the world The frequency and severity are increased by urbanization Avoid building on floodplains