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Chapter 11 -Water Resources
Water © “Water Planet”- Earth has an abundance of water in all forms: solid, liquid, and gas. © Renewable resource because it is circulated in the water cycle. © Humans can only survive a few days without water. © Two kinds of water on Earth: ©Fresh water- Can drink because it contains little salt. ©Salt water- Ocean water with a high concentration of salt.
The Water Cycle
Global Water Distribution © 97% salt water © 3% fresh water © 77% of fresh water frozen in icecaps and glaciers © 22% ground water © 1 % other
Global Water Distribution ©Surface water- Fresh water on Earth’s land surface. ©Lakes, rivers, streams, and wetlands ©River systems- Flowing network of water comprised of streams and rivers. ©Amazon river system- largest in the world ©Watershed- Area of land that is drained by a river.
Watersheds of the World
Global water Distribution © Ground Water- Water stored beneath the Earth’s surface in sediment and rock formations. ©Water table- Level where the rocks and soil are saturated with water ©Aquifer- Underground formation that contains water ©Porosity- Amount of space between the particles that make up a rock. ©Permeability- The ability of rock or soil to allow water to flow through it. ©Permeable- Allows the flow of water. ©Impermeable- Does not allow the flow of water.
Ground Water- Cont’d. ©The Recharge Zone- The area of the Earth’s surface where water percolates down into an aquifer. ©Wells- A hole that is dug or drilled to reach groundwater
Chapter 11 -Water Use and Management
Global Water Use © Most freshwater used globally to water crops. © 19% of global water use for industry © Only 8% of global water used for washing and drinking.
Residential Water Use © Striking differences among countries around the world © U. S. residents use on average 300 L of water per day © Indian residents use on average 41 L of water per day
Water Treatment ©Potable- Safe to drink. ©Treatment must remove elements: mercury, arsenic, and lead ©Found in polluted and ground water ©Pathogens- Organisms that cause illness or disease ©See Figure 6, Pages 276 -277
Water Use © Industrial- 19% of water use in world ©Manufacture goods ©Dispose of waste ©Generate power ©Most used to cool power plants © Agricultural- 67% of water use in world © 80% of water used in agriculture evaporates ©Irrigation- Method of providing plants with water from sources other than direct precipitation.
Water Management Projects © Aqueducts- Huge canals that brought water from the mountains to dry areas. © Dams and water diversion canals used today. © Water management projects today: ©Bring in water to make a dry area habitable ©Create a reservoir for recreation or drinking water ©Generate electric power
Water Management Projects ©Water Diversion Projects- To supply dry regions with water, all or part of a river can be diverted into canals that carry water across great distances.
Water Management Projects ©Dam- Structure built across a river to control the river’s flow. ©Can be used to generate electricity. ©Problems: flooding, ecosystem destruction, and dam failure ©Fertile sediment builds up behind dams ©Reservoir- Artificial lake formed behind a dam.
Water Conservation ©Water becomes more expensive as it depletes. ©Agriculture: Most water loss from evaporation, seepage, and runoff ©Drip Irrigation System- Small amounts of water delivered directly to roots using perforated tubing.
Water Conservation © Home: ©Water-saving technology such as low-flow toilets and shower heads ©Water lawns at night ©Xeriscaping- Designing landscapes that require minimal water use. © Industry: ©Recycling of cooling water and wastewater ©City wide/company wide water saving plans
Solutions for the Future © Desalination- Process of removing salt from salt water ©Heats water and collects evaporation ©Middle East/Kuwait has desalination plants © Transporting Water ©Transporting in bags and/or large plastic containers from abundant supplies to low supplied regions ©Towing icebergs? ?
Chapter 11 -Water Pollution
Water Pollution ©The introduction of chemical, physical, or biological agents into water that degrade water quality and adversely affect the organisms that depend on the water.
Types of Water Pollution © Nonpoint-source Pollution © Pollution that comes from many different sourecs © Difficult to identify and trace/regulate and control © 96% of polluted water in U. S © Point-source Pollution © Pollution discharged from a single source © Can be identified and traced ©.
Pollutant Types and Sources
Wastewater ©Water that contains waste from homes or industry. ©Treating ©Most contaminates are biodegradable ©Some toxic substances cannot be removed by standard treatment
Wastewater ©Sewage sludge ©Solid material that remains after treatment ©Sometimes hazardous waste ©Often incinerated and ash buried ©Can be used as fertilizer or bricks
Water Pollution © Eutrophication ©Containing an abundance of nutrients ©Leads to swamp or marsh ©Artificial Eutrophication. Sewage and fertilizer runoff enhances ©Ex: Algal blooms © Thermal Pollution. Increased temperature of water sources caused by factories and industries cooling systems ©Decreases oxygen levels ©Kills organisms
Water Pollution © Groundwater pollution- Polluted surface water percolates down to groundwater ©Leaking underground storage tanks are large problem ©Remains for 100 s to 1000 s of years © Ocean pollution ©Coastal ecosystems most affected ©Legal to dump in some parts of ocean ©Oil spills © 5% of ocean pollution ©Nonpoint-source pollution from land 10 times more than tanker spills
Water Pollution © Biomagnification. Accumulation of pollutants at successive levels of the food chain. ©Many pesticides ©Example: DDT and the Bald Eagle © Clean Water Act of 1972 To restore and maintain the chemical, physical, and biological integrity of the nation’s waters. © Goal to make fishing and swimming safe by 1983. © Not achieved © 30% increase © Opened door for more legislation
Water Quality Federal Laws