Two kinds Salt water Freshwater We can only live a few days without water, but we can live a month without food
The water cycle Continuous movement of water between earth and its atmosphere Is water a renewable resource?
Global water distribution What percent of earth is covered by water? About two thirds, or more specifically 71% What percentage of that water is salt water? 97% So 3% of water on earth is fresh water Most of this is ICE (77%) A lot is GROUNDWATER (22%) Less than 1% is SURFACE WATER (that we can drink)!
Most of the freshwater available for human use cannot be seen – it exists underground When it rains some water goes into the streams and rivers, but most of it percolates down through the soil and into the rocks below This water is called groundwater Groundwater
As you travel down through the earths surface, eventually you reach a point where the soil is saturated with water, this is the water table. The water table
Water Pollution Introduction of chemical, physical, or biological agents that degrade water quality Adversely affect the organisms that depend on water
Point source pollution Pollution from a single source
Non-point source Comes from many different sources that are often difficult to identify
Wastewater Water that contains waste from homes or industry
Artificial Eutrophication Nutrients are good for water….but… TOO much can be bad: When nutrients break down or decompose, they use up oxygen. Fertilizers cause excess phosphorus and nitrogen to enter surface water through sewage or runoff.
Thermal Pollution Did you ever think warmth can be a pollutant? It can, if a body of water rises just a few degrees, large amount of fish can die. Like eutrophication, thermal pollution causes decreased levels of oxygen in water, cold water holds more oxygen.
Groundwater Pollution Groundwater can get polluted through Pesticide Herbicide Petroleum products Very difficult to clean
Ocean Pollution Most of the pollution that occurs in the ocean comes from ACTIVITIES ON LAND. Oil spills
How do we clean up oil spills? Booms: Barriers to prevent the oil from spreading Dispersants: chemicals that break up the oil so that it is diluted by more water Pros/cons Skimmers: remove oil from the surface of water Burning
Ecosystem Biomagnification – buildup of pollutants at higher levels of the food chain
Cleaning up Cuyahoga River Clean Water Act of 1972 – Goal was to make all surface water clean enough to swim and fish in by ’83. Not met, but 30% increase Clean Air Act of 1990 – requires oil tankers traveling US water to have double hulls