Although water may seem abundant, only 3% of Earth’s water is fresh water. Of that, only 0.3% is available for use by us, plants and animals. The rest is frozen in glaciers and ice caps or too far underground to be used. The most recent national water quality information from the Environmental Protection Agency (EPA) shows that 50% of the rivers and streams that have been surveyed in the U.S. are still impaired by some type of pollution. Of the lakes, reservoirs and ponds that have been surveyed, 66% are impaired.
Most people think that storm water runoff goes through the storm drains to a treatment plant before being released to the river. Actually, the runoff drains directly to the river without any treatment whatsoever. As it travels to the storm sewer system the runoff picks up debris, chemicals, dirt and other pollutants and carries them straight into our rivers, lakes and streams.
The most recent EPA information places urban-related runoff/stormwater ninth in the probable sources of contamination to our rivers, streams and lakes.
Polluted runoff contaminates the water we use for drinking and recreation and can have adverse effects on humans, wildlife and plants. Some of these effects can include:
Bacteria and other pathogens can wash into water bodies causing health hazards for both humans and wildlife.
Chemicals such as insecticides, paint, solvents, and automobile fluids can poison aquatic life. Animals and humans can become sick or die from eating contaminated fish and shellfish or from accidentally ingesting polluted water.
Debris and garbage in the water can choke, suffocate or disable fish, amphibians and birds. It also ruins the aesthetics of the water body and makes recreation undesirable.
Excess sediment in the water can cause cloudiness which makes it difficult for aquatic plants to receive the sunlight they need to grow. Sediment can also build up in waterways altering their natural course which could lead to increased flooding. Those waterways used for navigation may need to be dredged to restore them.
Many water bodies are used as sources for drinking water. Pollution in a water body (from any source) increases the cost of treatment to make our drinking water safe.
Nutrients from decaying biological material (leaves, garbage, etc.) and the overuse of landscape fertilizers can cause algae to bloom excessively. As the algae dies off, they sink to the bottom and decompose in a process that removes oxygen from the water. Fish and other aquatic organisms can’t exist in water with low oxygen levels.
For more information about water quality in the U.S. and Colorado visit the EPA's website.