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.
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.
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.