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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%
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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
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Evaporation and transpiration
Ground Water 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
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Too Little Water Dry climate Drought Desiccation Water stress
Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million Water stress
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Problems with Using Groundwater
Water table lowering Depletion Subsidence Saltwater intrusion Chemical contamination Reduced stream flows
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Kinds of Water Pollution
Inorganic Pollutants Organic Pollutants Biologic Pollutants
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Case Study: The Great Lakes
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Types, Effects and Sources of Water Pollution
Point sources Nonpoint sources Water quality
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Point and Nonpoint Sources
Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES
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$23 billion/year for 8-10 years to bring clean drinking water to those who don’t have it
Consequences of a warmer world Pollution of freshwater streams Dilution and biodegradatoin Breakdown of pollutants by bacteria—oxygen sag curve
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Point source vs. non-point source pollution; developed vs
Point source vs. non-point source pollution; developed vs. non-developed. Developing countries: half of world’s 500 major rivers are heavily polluted
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Mississippi River Basin Ohio River Missouri River Mississippi River LOUISIANA Mississippi River Depleted Oxygen Gulf of Mexico
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Solutions: Preventing and Reducing Surface Water Pollution
Nonpoint Sources Point Sources Reduce runoff Clean Water Act Buffer zone vegetation Water Quality Act Reduce soil erosion
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Pollution of Lakes Eutrophication
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Groundwater Pollution: Causes
Low flow rates Few bacteria Low oxygen Cold temperatures Hazardous waste injection well Pesticides Coal strip mine runoff De-icing road salt Buried gasoline and solvent tank Pumping well Cesspool septic tank Gasoline station Waste lagoon Water pumping well Sewer Landfill Leakage from faulty casing Accidental spills Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow
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Groundwater Pollution Prevention
Monitor aquifers Find less hazardous substitutes Leak detection systems Strictly regulating hazardous waste disposal Store hazardous materials above ground
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Case Study: Chesapeake Bay
Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major problems with dissolved O2
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Ocean Pollution
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Coastal Water Pollution
Solutions Coastal Water Pollution Prevention Cleanup Reduce input of toxic pollutants Improve oil-spill cleanup capabilities Separate sewage and storm lines Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful byproducts (still under development) Ban ocean dumping of sludge and hazardous dredged material Protect sensitive areas from development, oil drilling, and oil shipping Require at least secondary treatment of coastal sewage Regulate coastal development Use wetlands, solar-aquatic, or other methods to treat sewage Recycle used oil Require double hulls for oil tankers
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Technological Approach: Septic Systems
Require suitable soils and maintenance
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Sewage Treatment Physical and biological treatment Fig p. 511
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Advanced (Tertiary) Sewage Treatment
Uses physical and chemical processes Removes nitrate and phosphate Expensive Not widely used
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Technological Approach: Using Wetlands to Treat Sewage
Fig p. 513
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Prevent groundwater contamination Greatly reduce nonpoint runoff
Solutions Water Pollution Prevent groundwater contamination Greatly reduce nonpoint runoff Reuse treated wastewater for irrigation Find substitutes for toxic pollutants Work with nature to treat sewage Practice four R's of resource use (refuse, reduce, recycle, reuse) Reduce resource waste Reduce air pollution Reduce poverty Reduce birth rates
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Wetlands Home to ~33% of nation’s threatened and endangered species
Statistics— 50% loss since 1900 in US; cities on filled wetlands; rising sea level Mitigation banking—Nat’l Academy: ~half of attempts to build a wetland fail. More than 500 wetland restoration banks in US
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Virtues of Wetlands Home to wildlife and flora Flood protection
Cycling and storage of chemical and biological substances Found at heads of rivers Remove toxins from sewage
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How Wetlands are Destroyed
Mostly by draining for development or farming. To ‘reclaim’ land along coastlines
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The Everglades ~77,000 sq km; 3 sub-basins
Thin sheet of water miles wide Formed ~5000 yrs ago--how Human influences: late 1880’s—first dredging 1907 and 1928: canals—saltwater; draining south of Lake O. : Kissimee River channelized 65% now drained Plants and animals depend on water level timing—seriously disturbed Number of species of wading birds—dropped 95% since 1947
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Protecting, Sustaining, and Restoring Wetlands
Regulations Wetlands protection Mitigation banking Wetlands restoration Control of invasive species
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