1. WATER RESOURCES  Essential for life (people can live roughly 3-4 days without water)  Renewable Resource  Percentages of water on Earth - 97% salt water 3% fresh water--- a) 77% of this is frozen b) 22% groundwater c) 1% potable water  Circulated through Earth by means of the water cycle

2. WATER CYCLE Driving force of water cycle-sun 1.Sun evaporates water from ocean, lakes, rivers, moist soils, through transpiration, and evaporation of our skin 2.Water vapors cool in the atmosphere and condenses as droplets in clouds 3.When clouds meet cold air it falls to Earth in the form of precipitate—rain, sleet, or snow (most falls into the ocean) 4.Precipitation that falls on land does one of three things 1. evaporates quickly 2. collects in streams and rivers 3. seeps into the soil (groundwater)

3. TYPES OF WATER SURFACE WATER— Above ground in lakes, ponds, rivers, and streams May come from Aquifers Runoff--- Water from rainfall and melting ice Flows down a slope; does not seep into ground Creates riffs- shallow grooves in ground

4. TYPES OF WATER GROUNDWATER Water within porous or jointed bedrock Soil zone– water that fills the spaces between soil particles Saturation zone- another name for AQUIFERS--- underground rock formation Water table– top of the zone of saturation Aeration zone-area where water enters the aquifer Recharge zone-area of land where groundwater originates Discharge zone- area where groundwater leaves the aquifer and becomes surface water Water moves only a few cm/year—amount depends on amount of precipitation, open space, porosity of rock, and slope of aquifer

5. OGALLALA AQUIFER Largest Aquifer in the world Holds about 2000 km 3 of water High Plains states depend on it for agriculture Scientists predict that the aquifer will run dry in about 40 years as a result of overdraft

6. WATER USE RESIDENTIAL USE average person uses 300L/Day outside water use accounts for half ActivityDaily Consumption Brushing teeth 19-39 L (faucets running) Showering 75-80L (faucets running) Tub bathing 96-116L (full tub) Toilet flushing 16-21 L (per flush) Washing face/hands 4-8 L (faucets running) Lawn sprinkler 40L (per minute) Swimming pool 100-1000L (per fill)

7. WATER USE INDUSTRIAL USE Industry uses 44% of all used fresh water Used as power source, transportation, waste disposal, mining, and refining of natural resources EX: 15,000L is used to make one washing machine 20,000+L is used to produce synthetic materials such as Rayon fabric

8. WATER USE Farming Practices FLOOD IRRIGATION flooding of a flat area advantage– inexpensive disadvantage-50% lost to evaporation FURROW IRRIGATION flooding of a flat area with furrows (ditches) advantage-better than flood irrigation water is deposited right to plants Disadvantage-evaporation rate is high mineral salts accumulate

9. WATER USE Farming Practices Overhead Irrigation sprinkler systems used on flat ground and uneven slopes Drip irrigation---developed in Israel  uses tubing to deliver water directly to root system of plants  expensive  used with irregular sloping or where water supply in low

10. WATER USE Farming Practices Subirrigation water is introduced naturally or artificially beneath the soil may develop an underground water source most effective in areas where underground water is already near the surface EX: The diversion of water from Mono Lake to LA -650 km away PROBLEM: Mono Lake is drying up and the salt concentration of the lake is increasing

11. WATER RESOURCE PROBLEMS Overdraft- occurs when an aquifer is drained faster than it is filled leads to: Subsidence---sinking of bedrock above aquifers Saltwater intrusion- problem is solved through the process of desalinization

12. SOLUTIONS Distillation---removal of salts from fresh water with high heat (too expensive to be feasible) Reverse --- using pressure to push water Osmosis through semipermeable membrane to remove salts Water ---- transporting icebergs Towing(expensive, ice melts) transporting water in plastic bags (floating bags down the coast?)