FRESHWATER

CHAPTER 10PG. 314

Section 1: Water on Earth

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WATER CYCLE

• The continuous process by which water moves from earth’s surface to the atmosphere and back.

• Involves: Evaporation, condensation, and precipitation

Evaporation

• Liquid changes to a gas (water vapor)

• Happens when water from surfaces of water heat up and rise into the air as a gas.

• Plants also release water vapor into the air

Condensation

• Warm air carries water vapor up where it hits colder air in the atmosphere and cools off.

• Drops of water clump together, forming clouds.

Precipitation

• Water droplets in the cloud grow larger, causing them to get heavy.

• Heavy drops fall back to the earth

Earth’s Water

• 97% salt water, 3% freshwater

• Oceans: Contain salt water– Parts named Pacific, Atlantic, Indian, and Arctic

• Ice: Sheets of freshwater cover Antarctica (S. Pole) and Greenland (N. Pole). Icebergs break off and melt as they get closer to warm water.

• Rivers & Lakes: Sources of freshwater for humans. Contain very little of earth’s freshwater.

• Groundwater: Fills cracks and spaces in soil. More freshwater located here than in rivers and lakes.

Section 2: Surface Water

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Rivers

• Snow melts on mountains, and water runs off, eventually forming rivers.

• Tributaries: Feed into the main river.– A river system is made of the river and its

tributaries.

• Watersheds provide water for the river. They are also known as drainage basins.

• Divides: Are ridges of land that divide or separate watersheds.– Continental Divide is the longest in North America

and follows along the Rocky Mountains.

Ponds

• Small, shallow areas of standing water

• They form when water collects in low areas or hollows (depressions) in the land

• Can get water from rain, snow, ice, or runoff.

Lakes

• Deeper and bigger than ponds, sunlight doesn’t reach the bottom of a deep lake.

• Lakes form from the same processes as ponds, movements of earth’s crust, volcanoes that block rivers, empty craters of volcanoes, or dams.

• Reservoirs are lakes that hold human water supplies.

Wetlands

• An area that stays wet most of the year.• 3 types– Marshes: Grassy, covered by shallow water (No

tall plants)– Swamps: Flooded forests with trees Y Shrubs,

mostly in warm, humid climates.– Bogs: Cooler areas left from melting ice sheets

and has lots of moss.

Wetlands (Cont…)

• Wetlands provide an area of nutrients that is good for growing certain foods, they provide habitats for animals, they help control floods by absorbing runoff from heavy rains.

Section 3: Water Underground

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How does groundwater move?

• Comes from precipitation

• It soaks into the ground from the force of gravity

• It moves and fills up spaces between particles and in cracks.

Permeable vs. Impermeable

• Permeable rocks have large pores that allow water to pass through easily

• Impermeable rocks, such as clay and granite don’t allow water through easily.

• The more permeable rock in an area=the easier it is for water to soak in to the ground there.

Saturated vs. Unsaturated

• Saturated Zone is totally filled (or saturated) with water…can’t take any more water– Top is called the Water table (uppermost layer of

groundwater in the saturated zone)

• Unsaturated zone is the area above the water table where more water can be absorbed.

Groundwater Coming to Surface

• Springs form when groundwater flows from bubbles or cracks that go deep into the land.

• Aquifers are underground layers of rock and sediment that hold water.

• An area where the aquifer has been drilled is known as a well. Here, they drill below the water table to bring water to the surface.

Pumps

• Pumps can be used to bring ground water up easier than using a crank bucket.

• Pumping water out too fast can cause the well to dry up.

Wells

• Artesian Wells are drilled where there is pressure in the aquifer that causes the water to rise on its own.

• A regular well requires an outside force to bring up the water.

Spring vs. Geyser

• Springs flow easily from cracks in the surface.

• Geysers are areas of hot springs where the water “erupts” from the earth with force. This force comes from the pressure in the steam of the water.