Chapter 11 WATER

DO NOW: Where does water come from? Is there more or less water on Earth than there was 1 billion years ago? The amount of water on Earth has not changed significantly since Earth formed. Water came from cooling rocks, which released a lot of water

The Water Cycle Three forms: solid, liquid, gas Renewable Resource (nonrenewable if what happens?)  Pollution!!! 1. Evaporation-from surface, water vapor rises 2. Condensation- gas cools & condenses into liquid (clouds) 3. Precipitation- water falls back to Earth

The Water Cycle

Global Distribution 97% is salt water 70% of Earth is water ONLY 3% is fresh water 70% of Earth is water

Global Distribution 3% FRESHWATER Of that 3% ONLY 23% is usable How much out of ALL water is usable? 0.23 x 0.03 = ???? (23%) x (3%) 0.7% of ALL water

Fresh vs. Salt Water Why can’t we drink salt water!?!?!!???

SURFACE WATER Surface water  fresh water on Earth’s land surface Ex: rivers, lakes, streams, wetlands

SURFACE WATER River Systems- network of water that flows into one larger river Watersheds- area of land drained by a river

GROUND WATER Groundwater- water stored beneath Earth’s surface in sediment and rock formations Most of the fresh water available for human use Water Table- a level beneath Earth’s surface where rock & soil are saturated with water Wet regions- near surface Deserts- far beneath surface

GROUNDWATER Aquifers- underground formation that contains groundwater Water table is upper boundary Rock, sand, gravel, limestone Space where water can accumulate

GROUNDWATER Porosity  the amount of space between the particles that make up a rock Permeability  the ability of rock/soil to allow water to flow through it  Permeable vs. Impermeable

GROUNDWATER Recharge Zone  area of Earth’s surface where water drains down into aquifer Depends on permeability above How do humans affect recharge zones?

Water Pollution

The Ogallala Aquifer One of largest in world Supplies 1/3 of U.S. groundwater used Glaciers at end of last ice age 174,000 sq. miles Pro Keystone Pipeline Against Keystone