Living in the Environment Water Resources G. Tyler Miller’s Living in the Environment 14th Edition Chapter 15

Key Concepts The physical properties of water Availability of fresh water Methods of increasing freshwater supplies Using water more efficiently Problems associated with flooding

Water’s Unique Properties Hydrogen bonding Liquid over wide temperature range Changes temperature slowly High heat of evaporation Great dissolving power Filters out ultraviolet radiation Adhesion and cohesion Expands when it freezes

Supply of Water Resources Freshwater Readily accessible freshwater Biota 0.0001% Rivers Atmospheric water vapor Lakes 0.0007% Soil moisture 0.0005% Groundwater 0.592% Ice caps and glaciers 0.014% Fig. 15-2 p. 307

Surface Water Surface runoff Watersheds Reliable runoff

Evaporation and transpiration Ground Water Fig. 15-3 p. 308 Evaporation and transpiration Evaporation Stream Infiltration Water table 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

Use of Water Resources Humans use about 54% of reliable runoff United States Industry 11% Public 10% Power cooling 38% Agriculture Agriculture Industry Domestic Power plants Fig. 15-4 p. 309

Too Little Water Dry climate Drought Desiccation Water stress Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million Water stress Fig. 15-6 p. 310

Using Dams and Reservoirs to Supply More Water: The Trade-offs Large losses of water through evaporation Flooded land destroys forests or cropland and displaces people Downstream flooding is reduced Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Can produce cheap electricity (hydropower) Migration and spawning of some fish are disrupted Provides water for year-round irrigation of cropland Fig. 15-9 p. 313

Transferring Water from One Place to Another Watershed transfer North Bay Aqueduct South Bay California Aqueduct CALIFORNIA NEVADA UTAH MEXICO Central Arizona Project Colorado River Los Angeles Shasta Lake Sacramento Fresno Phoenix Tucson ARIZONA Colorado River San Francisco San Diego California Water Project Central Arizona Project James Bay Fig. 15-13 p. 317

Tapping Groundwater Year-round use No evaporation losses Often less expensive Potential Problems! Refer to Fig. 15-15 p. 319

Problems with Using Groundwater Water table lowering (See Fig. 15-15 p. 319) Depletion (See Fig. 15-16 p. 320) Subsidence (See Fig. 15-16 p. 320) Saltwater intrusion (See Fig. 15-17 p. 320) Chemical contamination Reduced stream flows

Converting Salt Water to Fresh Water and Making it Rain Distillation desalination Reverse osmosis desalination Desalination is very expensive Cloud seeding

Using Water More Efficiently Reduce losses due to leakage Reform water laws Improve irrigation efficiency (Fig. 15-20 p. 324) Improving manufacturing processes Water efficient landscaping (xeriscaping) Water efficient appliances

Too Much Water: Floods Natural phenomena Aggravated by human activities Reservoir Dam Levee Flood wall Floodplain Fig. 15-24 p. 327

Solutions: Achieving a More Sustainable Water Future Efficient irrigation Water-saving technologies Improving water management See Fig. 15-26 p. 329