Presentation on theme: "Chapter 11 Water WATER AND HUMANS"— Presentation transcript:
1 Chapter 11 Water WATER AND HUMANS Section I Water ResourcesWater is ESSENTIAL to life.Can live almost a month without foodCan live only a few days without water. WHY?WATER AND HUMANS* The human body is more than 60 percent water. Blood is 92 percent water, the brain and muscles are 75 percent water, and bones are about 22 percent water.* A human can survive for a month or more without eating food, but only a week or so without drinking water.Chapter Water
2 EARTH - the Water Planet Water is essential to lifeAnimals drink itPlants must have itOceans don’t exist without itWater is called the “Universal Solvent” because so many substances dissolve in this polar substanceWe search for water on other planets as an indicator that life exists – or has existedWater exists on Earth as solid, liquid, and gasWater is critical to moderation of temperature on Earth
4 Global Water Distribution – 326 million trillion gallons! *97% is salt water – Desalination is expensive, but is a process used to obtain fresh water by rich, desert nations.*2.3% is frozen fresh water (glaciers and ice caps)*0.7% is liquid, fresh water for humans to use to grow crops, hydroelectric power, in industry, and in transportation.Surface water is water in streams, ponds, wetlands, rivers, and lakes that provides water for most large cities.River systems carry water to the ocean. Some of the world’s largest river systems are the Amazon, the Mississippi, and the Nile. The area of land drained by a river system is called a watershed.
5 WATERSHEDS of the WORLD Find the Amazon, Mississippi, Nile, Ganges, Ob, Yellow, Nile, Congo, Mekong, Yukon, Yangtze.
6 RIVERSHEDS OF GEORGIA Find the Altamaha, the Tennessee, the Chattahoochee, the Oconee, the Ochmulgee, the Coosa, and the Flint.Georgia’s 14 Major Watersheds. Georgia has 14 major watersheds: Altamaha, Chattahoochee, Coosa, Flint, Ochlockonee, Ocmulgee, Oconee, Ogeechee, Saint Marys, Satilla, Savannah, Suwannee, Tallapoosa and TennesseeTennesseeCoosaTallapoosaChattahoocheeFlintOcmulgeeOconeeSavannahOgeecheeAltamahaSatillaOchlockoneeSt. Mary’sSuwanneeCoosaOCNEChattahoocheeOCMULGESavannahOGECHFLINTALTMHSatillaOchlockonee
7 GROUNDWATER - Most of the freshwater that is available for human use is groundwater. (20 times the water in rivers and lakes!)Precipitation that falls and does NOT runoff into streams, rivers, lakes, and wetlands percolates through rocks and soil and is called Groundwater. Some cities and many individual households depend upon this groundwater as their water source.
8 Depending upon the structure of the soil and rocks underground, aquifers of varying sizes and depths contain much of Earth’s groundwater. Though rocks appear solid, many are porous, allowing water to seep through and finally fill all the tiny pores. Porosity is the percentage of the total volume of the rock that is pores. The more porous the rock, the more water it holds.The ability of rock or soil to allow water to flow through it is called Permeability. Clay and granite are impermeable materials, while sand, gravel, sandstone, and limestone are permeable materials SEE AQUIFER DIAGRAM ON PAGE 294-5
9 The Ogallala Aquifer The largest aquifer in North America holds about 1 quadrillion gallons of water and exists under the Midwestern states of SD, WY, CO, NE, KS, NM, OK, an TX. This aquifer is widely used for irrigation and for human and animal consumption. Because water is withdrawn 10 to 40 times faster than it is being replaced, the WATER TABLE has dropped more than 100 ft. since pumping began. The area of Earth’s surface where water percolates downward into an aquifer is called the RECHARGE ZONE. Why would it be important to keep pollution in these areas to a minimum? As more and more surface area has been paved or covered by buildings, more precipitation has tended to become runoff, reducing the amount of water that percolates the area and recharges aquifers. What is being done to reduce runoff? Many individual households rely on WELLS – holes that are dug or drilled – to access groundwater in aquifers. In many parts of the U. S., the water table generally stays around feet underground, making access easier. However, due to inconsistent amounts of precipitation, many wells are drilled several hundred feet – to a few thousand feet – to insure a constant supply of water. How do you account for the fact that groundwater is safe for human use, despite the fact that wastes from wildlife and from domesticated animals – AND HUMANS – is present in the area above aquifers???
10 SECTION 2 – WATER USE AND MANAGEMENT Globally about 67% of water is used agriculturally; 19% is used in industry; and 8% is used for residential use. Most industrial and residential water use is INDIRECT - that is – the water does not actually become part of the product or be drunk by the residents. Examples: 49 gallons of water are required to produce 1 gallon of milk (water for the cow; water used in making the polyethylene container and cap; water used in making the label) 132,000 gallons of water are used to manufacture a car! 80 gallons of water are used to produce one ear of corn!
11 Water is NOT used at the same rate in every country Water is NOT used at the same rate in every country. (Example: the average person in the U. S. Uses 80 gal of water every day, but in India the average person uses only about 7.5 gal) Since the U. S. is the most highly industrialized nation, water use in industry is much higher than in other less highly developed nations.Which continent would you predict to use the greatest volume of water in agriculture? Which continent would you expect to use the least volume of water for industry?
13 Purpose of Water Treatment All Surface Water (from lakes, rivers, and streams) is exposed to contamination from wildlife – and from humans: treated sewage and overflows from treatment plants. Animal wastes have the potential to cause disease from viruses, bacteria, and parasites – called PATHOGENS. Pollution from industry is also a danger. Water treatment must remove pathogens and heavy metals such as mercury (Hg), lead (Pb), and arsenic (As). The physical and chemical treatments on the previous slide are designed to make water POTABLE (safe to drink).
14 World Water Use 67% - Agriculture 19% - Industry 8% - Household Use Greater amounts of water are used for industrial purposes in industrialized nations; Greater amounts of water are used for agricultural purposes in countries with agricultural based economies (Asia, Africa, Australia, South America).Irrigation is needed for agriculture when rainfall is inadequate. Irrigation may be done by flooding shallow ditches, by high-pressure overhead sprinklers, or by controlled area drip irrigation. Which would be most efficient?
15 Water Management and Conservation: Romans built aqueducts centuries ago.Dams, reservoirs, and canals are modern tools to expand agricultural areas and make desert areas suitable for human development.(examples: Lakes Lanier and Allatoona; Water from Colorado River supplies much of California, Arizona, and Utah.)Reservoirs caused 50 million people to be displaced, and ecosystems were destroyed – so no new dams are anticipated in the U. S. Water management projects are still important in China, India, and South America.
16 Population growth increases need for potable water and water for growing crops. Water conservation by industry, households, and by agriculture is critical to maintain adequate supply.Alternate sources of water (desalination, glacier water, and transfers of fresh water) are being studied.
17 ONE BILLION PEOPLE ON EARTH (14% of the population) DO NOT HAVE ACCESS TO CLEAN WATER!Why? And Where is this such a terrible problem?List 6 Things You Can Do To Conserve Water
18 WATER POLLUTION POINT-SOURCE POLLUTION – EASY TO SPOT Leaking septic-tankLeaking storage lagoonUnlined landfillLeaking underground storage tanksLeaks from mining operationsPolluted water discharged by industryLeaks from waste-water treatment plants
19 WATER POLLUTION – Contd. NONPOINT-SOURCE POLLUTION - HARD TO SPOTChemicals from roadsRunoff from streets (contains oil, gasoline, wastes)Pesticides, herbicides, fertilizer from lawns, golf courses, farmlandFeces and chemicals from livestock feedlotsPrecipitation containing air pollutantsSoil runoff from farms and construction sitesOil and gasoline from watercraft