Water: Hydrologic Cycle and Human Use

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The World’s Fresh Water 9.25 trillion gallons 9.25 trillion gallons  69.6%  69.6% million trillion gallons are frozen in ice sheets, glaciers, permanent snow cover and permafrost.  30.1%  30.1% million trillion gallons are beneath the ground in soil and aquifers.  0.3%  0.3% - 31,341 trillion gallons are in lakes, rivers, wetlands – Also includes water in plants, animals, and the atmosphere.

Water: A Vital Resource

The Water Cycle

A B G I F Ground water loop Surface runoff loop Evapotranspiration loop C E D H Stores and Flows in the Cycle

Human Impacts on the Water Cycle Changing the Earth’s surface Floods Climate change Atmospheric pollution Withdrawing water supplies

Groundwater Decreased infiltration Increased runoff Decreased groundwater recharge

Human Impacts on the Hydrologic Cycle

Water Uses – 2/3 used to grow food

MEAT 1,857 gallons of water to produce 1 pound of beef 756 gallons of water to produce 1 pound of pork 469 gallons of water to produce 1 pound of chicken

To raise a cow or a steer in our industrial production system… 808,400 gallons of water for 18,700 pounds of pasture feed and hay + 6,300 gallons for drinking + 1,900 gallons for cleaning = 816,600 gallons used during the lifetime of the animal

Animal Products 1,382 gallons of water to produce 1 pound of sausage 589 gallons of water to produce 1 pound of processed cheese 400 gallons of water to produce 1 pound of eggs 371 gallons of water to produce 1 pound of fresh cheese 138 gallons of water to produce 1 pound of yogurt

Fruits & Veggies 185 gallons of water to produce 1 lb. of cherries 103 gallons of water to produce 1 lb. of bananas 84 gallons of water to produce 1 lb. of apples 78 gallons of water to produce 1 lb. of grapes 55 gallons of water to produce 1 lb. of oranges 33 gallons of water to produce 1 lb. of strawberries

Common Goods 2,900 gallons to produce 1 pair of blue jeans 2,800 gallons to produce 1 cotton bed sheet 766 gallons to produce 1 cotton T-shirt 634 gallons to produce 1 hamburger 53 gallons to produce 1 glass of milk 37 gallons to produce 1 cup of coffee 9 gallons to produce 1 cup of tea

So there were 2 fish swimming in a river… … One fish runs into a concrete wall and says… DAM!!

Funny Dam story.

Dams: Disrupt Integrity of River System Above the dam  Flooding  Sediment deposition  Loss of functional floodplain Below the dam  Loss of normal river flow patterns  Loss of river biota  Loss of functional floodplain

DAM! Dam projects have displaced up to 80 million people worldwide. The Itaipu dam in South America cost $18 billion and took 17 years to build. The weight of the 3 gorges reservoir tilted the Earth’s axis nearly and inch!

Hoover Dam – Colorado River on the border of Arizona and Nevada (Lake Mead)

DAM! Itaipu Dam 3 Gorges Dam

China’s 3 Gorges Dam

Consequences of Overdrawing Groundwater Falling water tables Diminishing surface waters (wetlands) Land subsidence Saltwater intrusion

Aquifer Exploitation Groundwater use exceeds aquifer recharge Many remaining aquifers are heavily polluted

Saltwater Intrusion

Using Less Water Irrigation  Surge flow  Drip irrigation $$$$ Municipal uses  Incentives and regulations limiting water use  Gray water

Desalting Seawater Reverse osmosis Distillation

National Water Policy Promote water efficiency Reduce or eliminate water subsidies Charge polluters Add watershed management to pricing of water

While Americans use about 100 gallons of water at home each day… Millions of the world’s poorest subsist on fewer than 5 gallons per day. 46% of people on Earth do not have water piped to their homes. Women in developing countries walk and average of 3.7 miles to get water. In 15 years, 1.8 billion people will live in regions of severe water scarcity. 1 out of 8 people lack access to clean water 3.3 million dies from water-related illnesses each year

Recreation More Americans fish than play golf or tennis. $33.6 billion The U.S. recreational boating industry generated $33.6 billion in In Florida, 3,000 gallons are used to water the grass for each golf game played. U.S. swimming pools lose 150 billion gallons every year to evaporation.