Water Resources G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 14 G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 14

Water’s Unique Properties Hydrogen bonding Hydrogen bonding Major factor in determining water’s unique propertiesMajor factor in determining water’s unique properties

O HH O HH O HH Hydrogen bonds Covalent bonds

Water’s Unique Properties Liquid over wide temperature range Liquid over wide temperature range High boiling point 100°C (212°F)High boiling point 100°C (212°F) Low freezing point 0°C (32°F)Low freezing point 0°C (32°F) Changes temperature slowly Changes temperature slowly Helps protect organismsHelps protect organisms Moderates the earth’s climateModerates the earth’s climate Excellent coolantExcellent coolant High heat of evaporation High heat of evaporation Absorbs heat as it changes into water vaporAbsorbs heat as it changes into water vapor Releases heat as vapor condensesReleases heat as vapor condenses

Water’s Unique Properties Great dissolving power Great dissolving power Carries dissolved nutrients into tissueCarries dissolved nutrients into tissue Flush waste products out of tissueFlush waste products out of tissue All-purpose cleanserAll-purpose cleanser Remove and dilute water-soluble wastesRemove and dilute water-soluble wastes pH pH Helps maintain balance between acids and basesHelps maintain balance between acids and bases Adhesion and cohesion Adhesion and cohesion Surface tensionSurface tension Wetting abilityWetting ability Expands when it freezes Expands when it freezes Ice floatsIce floats

Supply of Water Resources Freshwater Readily accessible freshwater Biota % Biota % Rivers % Rivers % Atmospheric water vapor 0.001% Atmospheric water vapor 0.001% Lakes 0.007% Soil moisture 0.005% Groundwater 0.592% Groundwater 0.592% Ice caps and glaciers % 0.014%

Surface Water Surface runoffSurface runoff –Water flowing off the land into bodies of water Reliable runoffReliable runoff –One-third of world’s annual runoff –Represents a stable source of water Watershed (Drainage Basin)Watershed (Drainage Basin) –Region from which water drains

Groundwater

Evaporation and transpiration Evaporation Stream Infiltration Water table Infiltration Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Aquifer Less permeable material such as clay Confirming permeable rock layer Ground Water Fig p. 315 Unconfined Aquifer Recharge Area

Use of Water Resources AgricultureAgriculture IndustryIndustry DomesticDomestic Power PlantsPower Plants  Humans use about 50% of reliable runoff United States Industry 11% Public 10% Powercooling38% Agriculture41%

Too Little Water 1)Dry climate Air circulation patternsAir circulation patterns 2)Drought 21 days+21 days+ Precipitation <70%Precipitation <70% Increased evaporationIncreased evaporation 3)Desiccation Drying of the soilDrying of the soil 4)Water stress Low per capita availabilityLow per capita availability Caused by increased populationCaused by increased population Limited runoff levelsLimited runoff levels Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million

Water stressed – reliable runoff per person below 1700 cu meters per year Water scarcity – per capita availability below 1000 cu meter per year 500 million people live in countries that are either water stressed or water scarce limited access (live far away) limited access (live far away) arrives during short periods arrives during short periods hydrological poverty hydrological poverty –Collect water from unsafe sources –Purchase from private vendor

Increasing Fresh Water Supplies 1.Build dams and reservoirs to store runoff 2.Bring surface water from another area via aqueducts/channels 3.Withdraw groundwater 4.Convert salt water to fresh water 5.Waste less water 6.Import food to reduce water use

Using Dams and Reservoirs to Supply More Water (To Dam or Not To Dam)

Fig a, p. 317 Provides water for year-round irrigation of cropland Flooded land destroys forests or cropland and displaces people Large losses of water through evaporation Provides water for drinking Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Risk of failure and devastating downstream flooding Can produce cheap electricity (hydropower) Downstream flooding is reduced Migration and spawning of some fish are disrupted

Deliver nutrients to the sea which helps to sustain coastal fisheries Deliver nutrients to the sea which helps to sustain coastal fisheries Deposit silt that maintains deltas Deposit silt that maintains deltas Purify water Purify water Renew and nourish wetlands Renew and nourish wetlands Provide habitats for aquatic life Provide habitats for aquatic life Conserve species diversity Conserve species diversity Ecological Services of Rivers

RUSSIA MONGOLIA CHINA NEPAL BHUTAN INDIA BANGLADESH BURMA LAOS VIETNAM PACIFIC OCEAN Beijing CHINA Jailing River Chongquing Yichang Wunan Yangtze River Shanghai YELLOW SEA EAST CHINA SEA Three Gorges Dam Reservoir China’s Three Gorges Dam

Dam Aqueduct or canal Upper Basin Lower Basin IDAHO WYOMING UTAH Salt Lake City Las Vegas CALIFORNIA Boulder City Los Angeles Palm Springs San Diego Mexicali Yuma Phoenix Tucson LOWER BASIN ARIZONA Grand Canyon UPPER BASIN Grand Junction Denver COLORADO NEW MEXICO Albuquerque MEXICO Lake Powell Glen Canyon Dam All-American Canal Gulf of California mi. 150 km The Colorado River Basin

Transferring Water from One Place to Another North Bay Aqueduct North Bay Aqueduct South Bay Aqueduct South Bay Aqueduct California Aqueduct CALIFORNIA NEVADA UTAH MEXICO Central Arizona Project Colorado River Aqueduct Los Angeles Aqueduct Shasta Lake Sacramento Fresno Phoenix Tucson ARIZONA Colorado River Sacramento River Sacramento River San Francisco Los Angeles San Diego Watershed transfer California Water Project California Water Project Central Arizona Project Central Arizona Project James Bay (Canada) James Bay (Canada)

Tapping Groundwater AdvantagesAdvantages –Year-round use –No evaporation losses –Often less expensive Potential Problems!Potential Problems! –Many

Problems with Using Groundwater 2)Aquifer depletion Ogalala AquiferOgalala Aquifer WYOMINGSOUTH DAKOTA NEBRASKA COLORADO KANSAS OKLAHOMA NEW MEXICO TEXAS 0100 Miles Kilometers Less than 61 meters (200 ft) meters ( ft) More than 183 meters (600 ft) (as much as 370 meters or 1,200 ft. in places) 0160

Problems with Using Groundwater 3)Subsidence –Sinking of land when groundwater is withdrawn

Other Effects of Groundwater Overpumping Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.

Converting Salt Water to Fresh Water Desalination – removing dissolved salts from ocean water or brackish water.Desalination – removing dissolved salts from ocean water or brackish water. –Distillation desalination Heating salt water until it evaporates.Heating salt water until it evaporates. –Reverse osmosis desalination Salt water is pumped at high pressure through a thin membraneSalt water is pumped at high pressure through a thin membrane

Converting Salt Water to Fresh Water Desalination – removing dissolved salts from ocean water or brackish water.Desalination – removing dissolved salts from ocean water or brackish water. –Desalination is very expensive Larger amounts of energy neededLarger amounts of energy needed –Desalination produces large quantities of wastewater waste disposal problemwaste disposal problem

Making it Rain Cloud SeedingCloud Seeding –Water condensation nuclei –Silver iodide particles Limited SuccessLimited Success –Not useful in dry areas –Potential pollution from cloud seeding chemicals –Legal disputes: ownership of clouds

Using Water More Efficiently Reduce losses due to leakageReduce losses due to leakage –60 to75% of water people use is lost! Causes of wasteCauses of waste –Water subsidy policy Artificially low cost of waterArtificially low cost of water False sense of abundanceFalse sense of abundance

Fig , p. 325 Center pivot Drip irrigation Gravity flow (efficiency 60% and 80% with surge valves) Above- or below- ground pipes or tubes deliver water to individual plant roots. Water usually comes from an aqueduct system or a nearby river. (efficiency 90–95%) (efficiency 80%–95%) Water usually pumped from underground and sprayed from mobile boom with sprinklers.

Too Much Water: Floods Natural phenomena heavy rain, melting snow Natural phenomena heavy rain, melting snow Floodplain Levee Flood wall Dam Reservoir Renew and replenish Aggravated by human activities

Solutions: Achieving a More Sustainable Water Future  Efficient irrigation  Water-saving technologies  Improving water management

What Can You Do? Water Use and Waste Use water-saving toilets, showerheads, and faucet aerators. Shower instead of taking baths, and take short showers. Stop water leaks. Turn off sink faucets while brushing teeth, shaving, or washing. Flush toilets only when necessary. Wash only full loads of clothes or use the lowest water-level for smaller loads. Use recycled (gray) water for lawn, gardens, house plants, car washing. Wash a car from a bucket of soapy water, and use the hose for rinsing only. If you use a commercial car wash, try to find one that recycles its water. Replace your lawn with native plants that need little if any watering and decorative gravel or rocks. Water lawns and gardens in the early morning or evening. Sweep or blow off driveways instead of hosing off with water. Use drip irrigation and mulch for gardens and flowerbeds.