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Science Unit 9 Lesson 3 Human Impact On Water

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What are some reasons why water is important?
1) Earth is the only planet with water.
2) Water shapes Earth's surface.
3) Water affects Earth's climate and weather.
4) Water is vital for life.
How much of the Earth's water is salty?
97%
How much of the Earth's water is fresh?
3%
How much of Earth's fresh liquid water is on the surface?
less than 1%
Areas with high densities of people, such as cities, need
lots of fresh water.
Sources of fresh water include
precipitation and melting snow or ice.
An aquifer is a
body of rock or sediment that can store a lot of water and that allows water to flow easily through it.
Wells are dug
into aquifers to reach water.
Permafrost is
a layer of soil found in polar regions where water is frozen.
Fresh surface waters include
streams, rivers, and lakes.
A lake is a
bowl shaped area which fills up when a stream flows into it.
Water quality is
measure of how clean or polluted water is.
It is vital for living things to not only have water but to have
clean water in order to survive.
Water supply is
the availability of water and influences where and when farmers grow crops and where people build cities.
Water supply systems
carry water from groundwater or surface waters so people can use the water.
A shortage of clean, fresh water
reduces quality of life for people.
Water pollution occurs when
waste or other material is added to water so that it is harmful to organisms that use it or live in it.
Point-source pollution
is pollution that comes from one specific site, for example, a chemical spill.
Nonpoint-source-pollution
comes from many small sources, is more difficult to control, and reaches water supplies usually by runoff or seeping into ground water.
Thermal pollution
is the heating of natural water by human activity.
An example of thermal pollution is
when water is used for cooling power plants and is returned to the lake at a higher temperature than the lake or river water. Warmer water has less oxygen available for organisms in the water.
Chemical Pollution occurs when
harmful chemicals are added to water supplies.
Two major sources of chemical pollution are
industry and agriculture.
Acid rain is
another form of chemical pollution.
Acid rain forms when
gases formed by burning fossil fuels mix with water in the air.
Acid rain can lower
the pH of soil and water and make them too acidic for life.
Biological pollution occurs when
live or dead organisms are added to water supplies.
Wastewater is
any water that has been used by people for such things as flushing toilets, showering or washing dishes.
Microbes from wastewater from feed lots may contain
harmful diseases such as dysentery, typhoid or cholera.
What threatens fresh water quality?
Thermal Pollution, Chemical Pollution, Biological Pollution and Eutrophication.
Eutrophication is the
increase in the amount of nutrients in water. Sometimes this occurs naturally.
Artificial Eutrophication occurs when
human activity increases nutrient levels in water, sometimes from wastewater and fertilizer runoff.
Artificial Eutrophication can cause
the fast growth of algae over the water's surface which can reduce oxygen levels and kill fish.
How is water quality measured?
By testing water with modern equipment to find small quantities of toxic chemicals or harmful organisms.
Water quality tests include testing the levels of
dissolved oxygen, pH, temperature, dissolved solids, the number and types of microbes in the water.
What is the measurement for dissolved solids?
It is the measure of the amount of ions or microscopic suspended solids in the water.
What is the measurement for pH?
It is the measure of how acidic or alkaline the water is.
What is the measurement for Dissolved oxygen?
It is the measurement of the amount of oxygen gas that is dissolved in the water.
What is the measurement of Turbidity?
It is the measure of the cloudiness of water that is caused by suspended solids.
What is the measurement of Microbial loads?
It is the identification of harmful bacteria, viruses or protists in water.
Flocculation is the process
where particles in water stick together (because of chemicals added to the water) and drop out of the water.
Flocculation also removes
harmful bacteria and other microbes.
Potable water is water which is
safe to drink.
What are the steps of water treatment?
1) Screens take out large debris.
2) Chemicals are added to water to cause particles to stick together and drop out of the water (flocculation).
3) Chlorine is added to kill microbes.
4) Air is bubbled through the water.
One water is used, it
becomes wastewater.
The Safe Drinking Water Act is
the main federal law that ensures safe drinking water for people in the United States.
A reservoir is
a body of water that usually forms behind a dam.
Aqueducts and canals are
artificial channels which diverts water from reservoirs to pipelines for human use.
__________ water is a term used to describe water that is safe to drink.
Potable
The addition of nutrients to water by human activity is called artificial _______________.
Eutrophication.
____________ pollution comes from many small sources.
Nonpoint-source
An example of ______ pollution would be when a person empties an oil can into a storm drain.
chemical
An example of ________ pollution would be when a factory releases warm water into a local river.
thermal
An example of _____ pollution would be when untreated sewage is washed into a lake during a rain storm.
biological
Name two ways in which humans can affect the flow of fresh water.
1) building dams to create reservoirs
2) pumping wastewater into streams
Why does wastewater need to be monitored?
Since wastewater contains pollution, it needs to be monitored to ensure life in the water is not destroyed.