Chapter 21 Water Supply, Use and Management

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

The water table is dynamic

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Over 99% of the Earth’s water is unavailable or unsuitable for beneficial human use It is expected that the total water withdrawn from streams and groundwater in the U.S will decrease but the consumptive use will increase

Additional Readings: Create an Excel Graph that Shows % of water distribution 1.Total Water on Earth 2.Breakdown of total freshwater distribution 3.Total potentially economically available freshwater as a percent of total freshwater 4.Total amount of actually available freshwater as a percentage of economically available freshwater (remove unusable water due to pollution, etc)

Groundwater level changes as a result of pumping in the Plains Region

Ogallala Aquifer The Ogallala Aquifer occupies the High Plains of the United States, extending northward from western Texas to South Dakota. The Ogallala is the leading geologic formation in what is known as the High Plains Aquifer System. The entire system underlies about 450,000 square kilometers (174,000 square miles) of eight states.Aquifer

Desalination as a Water Source Desalination: a technology to remove salt from water Increased cost Carlsbad desalination plant

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

Calculate the rough approximate discharge of a stream that is flowing according to the following diagram. Depth at this point is 2 ft Width is 6.5 ft. Velocity at this point is.42 meters per second

Click to see the Aral SeaClick to see the Aral Sea disappear!

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

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

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

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.

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

The Colorado River Basin

Longitudinal profiles of the Colorado and Green Rivers showing major dams and reservoirs and canyons

Additional Readings and Stuff: Determine which is your own watershed. Draw it out on a map Research and discuss channelization, point or non-point pollution issues, and any other things that make your watershed special