1. 11-1 Water Resources Fresh Water is a very limited resource!
Liquid fresh water for human use is even more limited! (comes mainly from lakes, rivers, groundwater)
71 % of Earth’s surface is water. Of this…
97% is salt water (oceans, seas)
3% fresh water. Of this…
77% of fresh water is frozen

2. 2 Main Sources of Freshwater:
1) Surface Water (water on Earth’s land surface)
In lakes, rivers, streams, wetlands.
Settlements (towns, cities) have been typically situated on sources of water.
Used for – drinking, crops, fish, power generation, transportation
River System: flowing network of water made of streams and rivers
More streams = larger river
Amount of water varies by season and year.
Amazon River System is the largest in the world.
Watershed: area of land that is drained by a river.
Pollution anywhere in a watershed may end up polluting a river.

3. 2) Groundwater: water stored beneath Earth’s surface in sediment and rock formations

4. Water table: area where rocks and soil are saturated with water (the top of an aquifer) – it is NOT level
Aquifer: underground formation that contains groundwater (often made of rock, sand, gravel)
Porosity: amount of space between the particles that make up a rock (more porous rocks hold more water)
Permeability: ability rock or soil to allow water to flow through it
Permeable = allows flow (gravel, sandstone, limestone, sand)
Impermeable = stops the flow of water (clay, granite)

5. Recharge Zone: area of Earth’s surface where water enters into the aquifer
* Environmentally sensitive areas (pollution in the recharge zone could enter the aquifer)
Well: hole dug/drilled to reach groundwater
Water filtered and purified as it travels underground
height of eater table changes seasonally
if water is pumped out faster than it’s replenished, water drops (well can go “dry”)

6. 11-2 Water Use and Management
3 Main Types of Water Use
1. Residential
About 14% of worldwide water use
Amount varies widely around the world
In U.S. about ½ is for activities inside the home (drinking, cooking, washing, flushing), ½ goes to outdoor activities (lawns, washing cars)
Water Treatment
Physical and/or chemical
Usually needed to make water potable (safe to drink)
Removes harmful elements (mercury, arsenic, lead) and pathogens (organisms that cause illness {bacteria, viruses, parasites, etc.})

7. 2. Industrial 19% of worldwide water use
Manufacturing, dispose of waste, generate power (1,000 L of water to make 1 kg of aluminum, 500,000 L of water to make a car)
Most used to cool power plants

8. 3. Agricultural Worldwide most water use is agricultural (67%).
Plants need a lot of water to grow (an ear of corn can take nearly 80 gal – about as much as you use in a day)
A lot evaporates
Irrigation: providing plants with water from sources other than direct precipitation

9. Water Management Projects
1. Water Diversion Projects
All or part of a river can be diverted into canals that carry water across great distances to supply dry regions with water. (The Colorado River is heavily diverted to places like AZ, UT, CA.)

10. 2. Dams & Reservoirs
Dam: structure built across a river to control the river’s flow
Reservoir: artificial lake that forms behind a dam
 Also used to generate electricity = hydroelectric dam
 Can be used for flood control, drinking, irrigation, recreation, industry
 Dams flood land behind them (displacing people and destroying ecosystems)
 Dams slow water, dropping sediment in reservoirs, robbing land downstream of nutrients
 Dam failure can cause death or injury below the dam

11. Water Conservation 1 way to ensure that everyone will have enough water at a reasonable price
1. Agricultural Water Conservation
Drip irrigation systems: deliver small amts. Of water directly to plants as needed, at a controlled rate – loses very little water to evaporation, seepage, or runoff
2. Industrial Water Conservation
Recycling cooling water and wastewater

12. 3. Home Water Conservation
Use only the water you need
Xeriscaping: designing a landscape that requires minimal water use (drought-tolerant plants)

13. Just a few things you can do to Conserve Water
Take shorter showers, and avoid taking baths unless you keep the water level low.
Install a low-flow shower head in your shower.
Install inexpensive, low-flow aerators in your water faucets at home.
Purchase a modern, low-flow toilet, install a water-saving device in your toilet, or simply place a water bottle (or brick) inside your toilet tank to reduce the water used for each flush.
Don’t let the water run while you are brushing your teeth.
Fill up the sink basin rather than letting water run when you are shaving, or washing dishes.
Wash only full loads in your dishwasher and washing machine
Water your lawn sparingly, and in the early morning or late evening to avoid evaporation

14. Solutions for the Future
As populations grow, other sources of fresh water need to be developed.
Desalination: removing salt from salt water – heat up salt water and collect the evaporation (consumes a lot of energy = expensive)
Transporting Water