environmental science chapter 20. “water, water, everywhere, nor any drop to drink” – the...
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Environmental ScienceCHAPTER 20
“Water, water, everywhere, nor any drop to drink” – The Rime of the Ancient Mariner
Water
300 Liters – average US person daily usage
Personal hygiene and home cleaning
Small amount of 300 Liters – cooking and cleaning
40 Liters – lawn sprinkler use every minute
15,000L of water to get the steel used to make one washing machine
Availability of water WON’T effect where companies locations are?
True or False?
Irrigation - Process of bringing water to an area for use in growing crops
Irrigation increases crop yield
9% of water is used by?
Residential
44% of water is used by?
Industrial
47% of water is used by?
Agriculture
Define
Flood Irrigation:
Flooding of an area land that is flat. It is wasteful because most of the water drains into soil
Furrow Irrigation:
Releases water into furrows, or ditches, dug between rows of crops. It’s used in flat areas evaporation rate is high and mineral salts accumulate quickly
Define
Overhead Irrigation:
Sprinkler systems. Drip, or trickle irrigation. Less efficient as winds increase
Subirrigation:
Water is introduced naturally or artificially beneath the soil
Effects of Water Use on Ecosystems
Mono lake to other areas
Mono Lake is a saltwater lake fed by streams that carry meltwater rich in dissolved minerals from surrounding mountains
No outlet – salts are left behind from evaporation
Humans began reverting meltwater for use; no water added to Mono Lake
A major rise in salt
Water Resources 20.2
Surface Water and Aquifers
Runoff - is the water that does not seep into the ground, but instead flows down a slope over land.
Rills - are shallow grooves that are carved from runoff
Soil water - is water that fills the spaces between soil particles
Joints - layers of bedrock beneath the soil that is full of cracks
Ground water – is the water within porous or jointed bedrock
A water table is the top of the saturated layer of rocks
Zone of Saturation - The saturated rock layer beneath the water table. Also know as an aquifer
Zone of Aeration - The area where groundwater enters an aquifer
Zone of Discharge – The area where groundwater leaves the aquifer and becomes surface water
Water Resource Problems
Overdraft – when a body of water is drained faster than it is filled
Two main problems with overdraft:
Saltwater intrusion – when saltwater intrudes into inland freshwater bodies, soil, and bedrock
Subsidence – when bedrock is weakened by the removal of freshwater from underground aquifers
Fig. 20.8 – Ogallala Aquifer
Water Treatment 20.3
Water
Tap water is not considered safe to drink in much of South America, Mexico, China, and parts of Africa.
A large supply of fresh water is essential to a nation’s development. Fresh water areas may not be able to support their human populations or the populations of other organisms.
Water
Penguins can tolerate the high concentration of salt in ocean water because they have special glands that remove the salts. Most organisms do no have such adaptations.
Desalination
The process by which salts are removed from water is called DESALINATION.
Desalination can be used to obtain fresh water for drinking, cooking, and irrigation. It also can be used to remove salt from agricultural waste water. For example, high concentrations of salt in the water of Colorado were killing the crops in Mexico.
Distillation
Salt water is heated to boiling
Water is evaporated and salt remains
Water vapor is cooled and fresh water collected
Reverse Osmosis
Salt water is forced through a strainer that traps the salt and lets the fresh water pass. The strainer is a thin membrane with tiny pores. The pores are large enough for water to pass through but too small for the salt.
Freezing
Salt water is frozen
As it freezes, salt and water separate
Fresh water is frozen and brine slush is secreted
Almost 1 million L of fresh water each day – Wrightsville Beach, North Carolina
Water Purification
The treatment of fresh water for the removal of minerals along with water treatment
Purification removes harmful chemicals and microorganisms which would usually make water unpotable
Several Processes:
Sedimentation
Filtration
Aeration
Sterilization
Sedimentation and Filtration
These processes use a series of screens to trap debris and other particles
Water is allowed to stand and over time, sediments settle to the bottom of the tank and purer water is left on top
COAGULANTS – chemicals added to the water to aid in the settling process (causes finer particle to clump together)
Water is then filtered through a 1M layer of sand for final purifying
Aeration and Sterilization
Water that has undergone Sedimentation and Filtration it can still have undesirable traits such as bad odor or taste due to dissolved gases
Aeration – the exposure of water to air
Any bacteria or microorganisms introduced during this process are killed using sterilizing chemicals such as chlorine and ozone which are very effective
True
Water purification removes harmful chemicals from the water.
Aeration is the exposure of water to air and sunlight.
True.
https://www.youtube.com/watch?v=r4cX2EPt2zE
https://www.youtube.com/watch?v=n7SZb53TE6U