chapter 2c section 1 fresh water is an essential resource
TRANSCRIPT
Chapter 2CSection 1
Fresh water is an essential resource.
Fresh water supports life.
Our bodies are more than ½ water.• Without water in your blood, your
cells would not receive the nutrients you need.
• Skin and tissues hold water in yourbody, but some is lost every day.
• Without water, a person cannot livefor more than a few days.
• Without water, people wouldn’t be able to grow food.
Fresh water on Earth is a limited resource.
• If too much water is taken from aquifers, the supply will eventually run out.
• If the water in rivers and lakes becomes polluted, we can no longer use it.
Most human activities require water.
• Farming• Industry• Transportation and Recreation• Fisheries and Aquiculture• Energy
Farming
• In U.S., about 40% of the water that is used goes to growing crops and raising livestock.
• Irrigation – in drier areas, farmers draw water from aquifers, rivers, or lakes to grow crops
1. Flood irrigation – pours water through canals and waterways so that it flows through the fields
2. Spray irrigation – sprays water onto the fields
Irrigation
• Flood Irrigation • Spray Irrigation
Industry
• Making cars – begins with the mining of minerals and ends with the final washing
• Huge amounts of water are used to cool down machines.
• Coal mine – water is used to separate chunks of coal from other clumps of dirt and rock
• Paper mill – uses 100 to 300 metric tons of water to manufacture one ton of paper
• Factories can clean the water they use and return most of it to lakes and rivers
Industry
Transportation and Recreation
• In the U.S., major rivers and the Great Lakes provide an efficient way to transport goods.
• On the Great Lakes, large ships carry iron ore from Minnesota to cities where it is used to make steel.
Continued…
• Whitewater rafting, canoeing, and kayaking• Along the shores – camp, picnic, swim, and fish
Continued…
• A river may flow too fast or be too shallow for safe travel, so people dig channels called canals that bypass rough spots and connect waterways.
Fisheries and Aquaculture
• Rivers and lakes provide fish for our food and also provide food for frogs, insects, birds, and larger mammals.
• Aquaculture – the science and business of raising and harvesting fish in a controlled situation (provide a cheap, ready source of catfish, trout, and salmon)
• To help maintain the population of fish in rivers and lakes, fish hatcheries are used to raise fish to release into lakes and rivers.
Continued…
Energy
• Dam – a structure that holds back and controls the flow of water in a river or other body of water
• Hydroelectric dam – water rushing through the dam turns machines called turbines, generating electricity
• Many plants us coal or nuclear power to heat water, creating steam that turns the turbines.
• Nuclear power stations also use water to cool the system.
Energy
• http://www.duke-energy.com/about-energy/generating-electricity/nuclear-how.asp
• http://www.duke-energy.com/about-energy/generating-electricity/pumped-storage-how.asp
• http://www.duke-energy.com/about-energy/generating-electricity/coal-fired-how.asp
Dams and other structures alter rivers.
• When a dam is built on a river, the landscape and the shape of a river are greatly changed.
1. Below the dam, the speed and volume of water flow may change, making a new ecosystem.
2. Behind the dam, water may collect and form a lake covering what once had been a river valley.
Reservoirs
• A reservoir is a lake that is used to store water.1. Many communities rely on reservoirs for their water
needs.2. They provide opportunities for boating and other
recreational activities.
Locks
• A lock is a section of waterway, closed off by gates, in which the water level is raised or lowered to move ships through.
• They are used in canals and rivers that connect lakes of different elevations.
• They are used in canals that slope upward then downward, such as the Panama Canal.
• The Panama Canal is dug into a strip of land between the Atlantic and Pacific Oceans, allowing ships a handy shortcut.
The Welland Canal
• The Welland Canal was built to connect Lake Ontario and Lake Erie.
• The southern end, on Lake Erie, is 326.5 ft. higher than the northern end on Lake Ontario.
• There are a series of 8 ship locks to raise and lower the ships as they navigate the canal.
• The length is 26 miles, and it takes ships an average of 11 hours to traverse the entire length.
The Welland Canal
Locks– https://www.youtube.com/watch?NR=1&v=U15Fwo9tbJ4&feature=endscreen&safe