Chapter 11: Water. A. The Water Cycle Water is a resource because it is circulated in the water cycle.

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1 Chapter 11: Water Sectin 1: Water Resurces Objectives 1. Describe the distributin f Earth s water resurces. 2. Explain why fresh water is ne f Earth s limited resurces. 3. Describe the distributin f Earth s surface water. 4. Describe the relatinship between grundwater and surface water in a watershed. A. The Water Cycle Water is a resurce because it is circulated in the water cycle. B. Glbal Water Distributin (Fig. 2, p. 270) Earth is abut 71% water: 68.87% (r 97% ttal water) is saltwater (ceans) 2.13% (r 3% ttal water) is freshwater, which is fund in (1.64% r 77% ttal freshwater) (0.47% r 22.1% ttal freshwater) Lakes, streams, sil, atmsphere, etc. (0.02% r 0.9% ttal freshwater) C. Surface Water Includes all fresh water that is abve grund: lakes, streams, wetlands, etc. Prvides drinking water, fd, pwer, and transprtatin 1. River Systems Streams frm as runff, either frm precipitatin r snwmelt, drains frm higher elevatins. Streams cmbine t frm rivers, and rivers cmbine t frm river systems. Largest river system in Nrth America: Largest river system in the wrld: 2. Watersheds (Fig. 3, p ) Drain variable amunts f water frm seasn t seasn and year t year Largest watershed in Nrth America: Largest watershed in the wrld: D. Grundwater (Fig. 4, p ) Is water stred in the grund Makes up the majrity f fresh water Water table Is the level undergrund at which rcks and sil are saturated with water Varies with climate: clse t surface in wet/humid areas and far belw surface in arid/dry areas 11-1

2 1. Aquifers Are undergrund rck frmatins that stre grundwater Cnsist f materials, such as rck, sand, and gravel, that have pen spaces, r pres Are an imprtant water surce fr cities and agriculture 2. Prsity and Permeability Prsity: the percentage f the ttal vlume f a rck r sediment that cnsists f pen spaces Permeability: the ability f a rck r sediment t let fluids pass thrugh it pen spaces r pres Permeable ; examples: sandstne, limestne, r layers f sand r gravel vs. Impermeable ; examples: clay, granite, metamrphic rcks, cncrete, asphalt 3. The Recharge Zne Size is dependent n the permeability f the surface abve the aquifer Is highly susceptible t pllutin Recharge can take a few years t 1000s f years 4. Wells Are hles that are dug r drilled t reach grundwater Dry up when water table falls belw the bttm generally due t a drught r (pumping ut water faster than it is recharged) Sectin 2: Water Use and Management Objectives 1. Identify patterns f glbal water use. 2. Explain hw water is treated s that it can be used fr drinking. 3. Identify hw water is used in hmes, in industry, and in agriculture. 4. Describe hw dams and water diversin prjects are used t manage freshwater resurces. 5. Identify five ways water can be cnserved. A. Glbal Water Use (Fig. 5, p. 277) Mst used fr Usage affected by availability f freshwater, ppulatin size, and ecnmics 11-2

3 «lack access t clean water (Wrld Health Organizatin). B. Residential Water Use (~8%) Water must be, r safe t drink. Water Treatment Used t remve txic elements, such as mercury (Hg), arsenic (As), and lead (Pb); and pathgens such as bacteria, viruses, prtza, and parasitic wrms Steps (Fig. 6, p. 277) (1) (2) (3) (4) (5) (6) C. Industrial Water Use (~19%) Used t manufacture gds, dispse f waste, and generate pwer D. Agricultural Water Use (~67%) Up t 80% f the water used evaprates befre reaching plant rts Irrigatin methds: water-filled ditches, high pressure sprinklers (mst cmmn in US but inefficient) E. Water Management Prjects 1. Water Diversin Prjects All r part f a river can be diverted t supply dry regins with water 2. Dams and Reservirs : built t cntrl water flw, but als useful fr generating electricity (20% f wrld s energy) : frm behind dams; water can be used fr fld cntrl, drinking, irrigatin, recreatin, and industry Cnsequences: species may be displaced, ecsystems may be destryed (behind and belw the dam), failure may cause deaths F. Water Cnservatin 1. In Agriculture 11-3

4 Water lss due t evapratin, seepage, and run-ff Cnservatin strategies: drip irrigatin systems, watering early r late 2. In Industry Strategies: recycle cling water and wastewater; financial incentives t cnserve 3. At Hme (Table 2, p. 282) Strategies: water-saving technlgy, xeriscaping G. Slutins fr the Future 1. Desalinatin (1) Water is heated, which frces the water t evaprate. (2) The water vapr (steam) is cllected. «EXPENSIVE 2. Transprting Water Ship water frm ne area t anther ~50% f US freshwater is fund in Alaska ~77% f Earth s water is frzen in icecaps and glaciers why nt tw an iceberg? EXPENSIVE and inefficient 3. Other : water is pushed thrugh a semipermeable membrane that prevents the salt frm passing thrugh Sectin 3: Water Pllutin Objectives 1. Cmpare pint-surce pllutin and nnpint-surce pllutin. 2. Classify water pllutin by five types. 3. Explain why grundwater pllutin is difficult t clean. 4. Describe the majr surces f cean pllutin, and explain the effects f pllutin n ecsystems. 5. Describe six majr laws designed t imprve water quality in the United States. A. Pint-surce Pllutin Is discharged frm a single surce, such as a factry, a waste water treatment plant, r leaking il tanker Can generally be identified and traced but clean-up is difficult t enfrce Surces (Table 3, p. 284): B. Nnpint-surce Pllutin Cmes frm many surces, such as streets and strm sewers Surces (Table 4, p. 285): 11-4

5 C. Principal Water Pllutants (Table 5, p. 286) Type f Pllutant Agent Majr Surces 1. Disease-causing rganisms, such as bacteria, viruses, prtza, and parasitic wrms 2. Animal and plant matter remains, feces, fd waste, and debris frm fd-prcessing plants 3. Pesticides, fertilizers, plastics, detergents, gasline and il, and ther materials made frm petrleum 4. Inrganic chemicals Mstly nnpint surces; sewage r animal feces, livestck feedlts, and pultry farms; sewage frm verburdened wastewater treatment plants Mstly nnpint surces Mstly nnpint surces; farms, lawns, glf curses, rads, wastewater, unlined landfills, and leaking undergrund strage tanks 5. Pint surces and nnpint surces; industrial discharge, unlined landfills, sme husehld chemicals, and mining prcesses; heavy metals als ccur naturally in sme grundwater 6. Physical agents Pint surces and nnpint surces; heat frm industrial prcesses and suspended slids frm sil ersin A. Wastewater 1. Treating Wastewater (Fig. 17, p. 287) Primary Treatment (1) (2) Secndary Treatment (3) (4) (5) 2. Sewage Sludge Sewage sludge: the slid material that remains after wastewater has been treated Dispsal: difficult and expensive if it cntains txic r hazardus materials (hazardus waste) B. Artificial Eutrphicatin Eutrphicatin: natural prcess f nutrient enrichment 11-5

6 Artificial eutrphicatin: human-induced eutrphicatin; excess can lead t algal blms Surces f excess P and nitrgen (N): detergents, animal waste, and fertilizer C. Thermal Pllutin Is a human-induced increase in the temperature f a bdy f water, which has a harmful effect n water quality and n the ability f that water t supprt life Can ccur when industrial cling water is discharged int a bdy f water D. Grundwater Pllutin (Fig. 20, p. 290) Surces: pesticides, herbicides, chemical fertilizers, petrleum prducts, etc. frm surface water pllutin, undergrund strage tanks, unlined landfills, etc. The Envirnmental Prtectin Agency (EPA) has detected hazardus chemicals that can seep thrugh the sil and int the grundwater. Cleaning up is difficult and may take 1000s f years E. Ocean Pllutin cmes frm land activities: Sme due t rivers, which carry runff t the cean Mst frm near-shre activities, primarily threatening sensitive near-shre ecsystems like estuaries and cral reefs millin gallns f il/year cmes frm ther surces: Ships legally dump wastewater and garbage Accidental il spills (Fig. 21, p. 291): ~37 millin gallns/year spilled by tankers (=5% f all il pllutin in the ceans) The discharge f il and the dispsal r abandnment f plastics in the cean r castal water regulated by laws (UN 1982) Natin s laws extend 22 km frm shre = Natins have cntrl ver ecnmic activity, envirnmental preservatin and research ut t 370 km frm shre = The rest f the cean is cmmunal prperty cntrlled by the F. Water Pllutin and Ecsystems : accumulatin f pllutants at successive levels f a fd chain Example: DDT bimagnificatin (Fig. 22, p. 292) G. Cleaning Up Water Pllutin 11-6

7 : restre and maintain the chemical, physical, and bilgical integrity f the natin s waters Nt much prgress: ~30% increase Led many states t adpt stricter water-quality standards Led t ther federal laws (Table 6, p. 293) (1) Marine Prtectin, Research, and Sanctuaries Act f 1972, amended 1988: (2) Safe Water Drinking Act f 1975, amended 1996: This act intrduced prgrams t prtect grundwater and surface water frm pllutin. The act emphasized sund science and risk-based standards fr water quality. The act als empwered cmmunities in the prtectin f surce water, strengthened public right-t-knw laws, and prvided water system infrastructure assistance. (3) Cmprehensive Envirnmental Respnse Cmpensatin and Liability Act f 1980 (CERCLA): AKA Superfund Act. The act makes wners, peratrs, and custmers f hazardus waste sites respnsible fr the cleanup f the sites. The act has reduced the pllutin f grundwater by txic substances leached frm hazardus waste dumps. (4) Water Quality Act f 1987: (5) Oil Pllutin Act f 1990: 11-7