Water!! Water!! APES: Chapter 12
In Groups of 4: • What is the difference between: • Aquatic • Marine • Limnology • Freshwater • How much of our world is covered in water? • Fresh vs salt • List @ least 5 ways humans use water
Freshwater First ;) D:\Chapter_12\C_Animation_and_Video_Files\ABC News Video Clips\water_wars
Activity: • Same Groups, Using your textbook: • List the freshwater systems • What is the difference between consumptive and non-consumptive use? Give examples • List the 4 ways humans use water • Check out figure 12.10 page 263: what are your thoughts? • Answer the Weighing the Issues Reaching for Water on page 264 as H/W tonight
Water!! Water!! APES: Chapter 12
Most Water is in the Ocean • ~97.5% of water on Earth is in the ocean • ~2.5% is considered Fresh
So lets talk Freshwater • Name some freshwater ecosystems • Rivers, bogs, marshes, lakes, ponds, streams, swamp • How does groundwater effect hydrologic system? • Storage of freshwater to be used slowly, and replenished in equal amounts • What is an aquifer? • Areas of in-ground water storage: rock that is spongy or porous (rock, sand or gravel)
Stats: • Ground waters average age: 1,400 years!! • Some can be 10’s of thousands of years old!!!! • The US releases 492 Billion gallons of water per day from its aquifers!!!! • On average, surface water enters aquifers at a rate of 3 ft per day. • Is this sustainable?
We are depleting groundwater • Groundwater is easily depleted, because aquifers recharge slowly. • Most water goes to agriculture. • Amount of irrigated land is increasing. • Water is being “mined”: 15-35% of irrigation withdrawals are unsustainable. • As aquifers become depleted: • Water tables drop • Salt water intrudes in coastal areas • Some cities (Venice, Mexico City) are slowly sinking • Wetlands dry up
The Ogallala Aquifer • The world’s largest known aquifer • Underlies Great Plains of U.S.- 8 states • Most bountiful grain-producing region in world because of H2O • It is down 10% = 18 yrs of Colorado River Flow!! Overpumping has reduced the aquifer’s volume by 10%.
Equal Shares for Everyone? • No…. • Water is NOT infinite and everywhere • MANY MANY nations with high populations of people have very very little water • Or no access to it
Water is unequally distributed in space and time • Different regions possess different amounts of groundwater, surface water, and precipitation. • Many areas with high population density are water-poor and face serious water shortages. • Dams store water so it can be used when needed.
Climate change may bring water shortages • Climate change will cause: • Altered precipitation patterns • Melting glaciers • Early season runoff • Intensified droughts • Flooding • Models predict a drier future for the American Southwest. • 4 western states are building new water supply projects for $2.5 billion.
Activity: • Comprehension question 1-3 due today • Print off Section 1 readings to work on in class Monday….. Quite a lot of work, so if you complete over the weekend… ;)
Homework for This Weekend: • Pre-read next section: • “Solutions to Depletion of Fresh Water” • Answer Questions 4-5 of Testing Your Comprehension • Print off and complete from web-site, • “Ch 12 Freshwater Activity,”. • Be prepared to discuss on Monday, must have work available for a grade ;)
Activity: • In groups of 2: • Explain how a dam works (p. 361-363) and what they do: remember that dams of today are very different • Include the terms Consumptive/Nonconsumptive • Where are the largest dams located • Include both benefit and cost • What is a Dike/Levee? How do they work, etc. • Benefit vs cost • How/Why are we depleting Surface Water? • Benefit vs cost • Give examples • How/Why are we depleting Ground Water? • Benefit vs cost • Give Examples • What is the future outlook when it comes to Water Wars?
We have erected thousands of dams • Dam: an obstruction placed in a river or stream that blocks water flow so that water can be stored in a reservoir • Prevents floods, provides drinking water and irrigation, and generates electricity • Only a few major rivers in remote regions remain undammed. • Dams are dismantled when their costs outweigh their benefits. • 500 dams have been removed in the U.S. • Rivers with dismantled dams: • Have restored riparian ecosystems • Reestablished fisheries • Revived river recreation
Problems??? • What happens when you build a dam? • HELP!! • Sediment accrues up river • Sediment is washed out downstream • Ecosystems are destroyed • Areas are flooded, encasing all materials in water • Factories, chemicals, grasslands, habitat, homes….
China’s Three Gorges Dam • The largest in the world • Electricity, shipping, flood control • May replace coal or nuclear plants • Cost $25 billion to build • 10 trillion gallons of water • Flooding cities/homes 1.2 mil displaced • Submerging archaeological sites • Drowning farmland /wildlife habitat • Suspended sediments/waste/will fill the reservoir • Sub-climates/hydrologic cycle changes
On the Other Hand….. • At full power, Three Gorges reduces coal consumption by 31 million tonnes per year, avoiding 100 million tonnes of greenhouse gas emissions, millions of tonnes of dust, one million tonnes of sulfur dioxide, 370,000 tonnes of nitric oxide, 10,000 tonnes of carbon monoxide, and a significant amount of mercury. Hydropower saves the energy needed to mine, wash, and transport the coal from northern China.
Cntd • From 2003 to 2007, power production equaled that of 84 million tonnes of standard coal, reducing carbon dioxide by 190 million tonnes, sulfur dioxide by 2.29 million tonnes, and nitrogen oxides by 980,000 tonnes. • The dam increased the Yangtze's barge capacity sixfold, reducing carbon dioxide emission by 630,000 tonnes. From 2004 to 2007 a total of 198 million tonnes of goods passed through the ship locks. Compared to using trucking, barges reduced carbon dioxide emission by ten million tonnes and lowered costs by 25%. Wikipedia
Will we see a future of water wars? • Freshwater depletion leads to shortages, which can lead to conflict. • 261 major rivers cross national borders. • Transboundary disagreements are common. • Water is a key element in hostilities among Israel, Palestinians, and neighboring countries. • Many nations cooperate with neighbors to resolve disputes. • Treaties have been signed by nations in Europe along the Rhine and Danube rivers. • What do YOUthink????? • Another way to die!!!
Activity: • Pre-read next section, “Solutions to Depletion of Fresh Water” • Answer Questions 4-5 of Testing Your Comprehension • Print off and complete from web-site, Ch 12 Freshwater Vocabulary • Be prepared to discuss tomorrow, must have work available for a grade ;)
Waste-water Treatment APES Water: The Story of Stuff
Indicators of water quality • Scientists measure properties of water to characterize its quality. • Biological indicators: presence of fecal coliform bacteria, algae, and aquatic invertebrates • Chemical indicators: nutrient concentration, pH, taste, odor, hardness, dissolved oxygen • Physical indicators: temperature, color, turbidity
Groundwater pollution is a serious problem • Groundwater pollution is hidden (“out of sight, out of mind”). • Difficult to monitor and manage • Retains contaminants for decades and longer • Some toxic chemicals occur naturally. • Aluminum, fluoride, sulfates, arsenic • Pollution from human activity is widespread. • Wastes leach through soils • Pathogens enter through improperly designed wells. • Hazardous wastes are pumped into the ground. • Underground storage and septic tanks may leak.
Legislative efforts reduce pollution • Clean Water Act (1977) • Illegal to discharge pollution without a permit • Standards for industrial wastewater • Funded construction of sewage treatment plants • Legislation has improved the situation. • Conditions improve when citizens push governments. • Other nations have also reduced pollution.
We treat our drinking water • EPA sets standards • It is chemically treated, filtered, and disinfected • Wastewater: water that has been used by people • Sewage, showers, sinks, manufacturing, storm water runoff • Septic systems: wastewater disposal in rural areas • Underground septic tanks separate solids and oils from wastewater. • The water drains into a drain field and decomposes. • Solid waste is periodically pumped and landfilled.
Municipal sewer systems • In populated areas, sewer systems carry wastewater. • Physical, chemical, and biological water treatment • Primary treatment: the physical removal of contaminants in settling tanks (clarifiers) • Secondary treatment: water is stirred and aerated so aerobic bacteria degrade organic pollutants • Chlorine-treated water is piped into rivers or the ocean. • Reclaimed water can be used for irrigation, lawns, or industry. • Dried solid material (sludge) is landfilled, incinerated, or used as fertilizer.
Artificial wetlands • Natural and artificial wetlands can cleanse wastewater. • After primary treatment at a conventional facility, wastewater is pumped into the wetland. • Microbes decompose the remaining pollutants. • Cleansed water is released into waterways or percolated underground. • Constructed wetlands serve as havens for wildlife and areas for human recreation. • More than 500 artificially constructed or restored wetlands exist in the U.S.
Activity: • Pre-read next section; Marine and Coastal Ecosystems: pages 269-275 • Answer Questions 6-7 of Testing Comprehension
Activity: • List the 5 major oceans; describe the physical makeup of the ocean • Include; currents, Coriolis Effect (p. 286), Upwelling, Downwelling, Marianas Trench, the longest mtn chain, convergent/divergent/transform fault boundaries (p. 236 237), photic/benthic/pelagic zones • The text list 8different coastal ecosystems. List them including unique features • Figure 12.17 shows the profile of the benthic zone; • Where does seafloor spreading occur? Sub-duction? What can you expect along trenches? Is the Pacific or the Atlantic more likely to have seismic activity? why? • Compare/Contrast the following: rocky intertidal zone, salt marsh, mangrove forest. • Include where they are located • ~2/3rds of human pop. Live w/in 100 miles of an ocean. Describe the ways in which this has altered these ecosystems. Due to me: Monday, 3/17/14