Water in the American West
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This EcoWest presentation examines water in the American West and the challenges of managing rising demands in a region with limited freshwater supplies. Learn more at EcoWest.org
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Water in the American West
- 1. EcoWest mission Inform and advance conservation in the American West by analyzing, visualizing, and sharing data on environmental trends. 1/20/2013 1
- 2. EcoWest decks This is one of six presentations that illustrate key environmental metrics. Libraries for each topic contain additional slides. Issue Sample metrics Water Per capita water consumption, price of water, trends in transfers Biodiversity Number of endangered species, government funding for species protection Wildfires Size and number of wildfires, suppression costs Land Area protected by land trusts, location of proposed wilderness areas Climate Temperature and precipitation projections Politics Conservation funding, public opinion Download presentations and libraries at ecowest.org 1/20/2013 2
- 3. Executive summary • The American West is facing a water crisis that is being compounded by population growth and climate change. • In most parts of the West, water is an especially scarce resource. The 11 coterminous Western states average just 18 inches of precipitation per year compared to 37 inches for the United States as a whole. • Scientists believe climate change will make the Southwest even drier and shrink the snowpack in many locations. • Although overall water use has leveled off over the past few decades, total municipal demand is increasing as cities continue to grow. • Laws like the Clean Water Act have reduced pollution and Western streams tend to have better water quality than those in other regions, but lakes are in poorer condition. Nutrient loading and degraded lakeshore habitat pose the greatest threats in the West. • The nation’s water infrastructure is crumbling, with hundreds of billions required to fix dams, levees, sewage plants, and drinking water systems. • Looking ahead, proposed water management strategies include water conservation, water reuse, reforms to state water laws, expanded water markets, and desalination. 1/20/2013 3
- 4. Table of contents 1. Water supply 4. Freshwater habitat • Total water supply • Biodiversity • Precipitation and drought • Habitat disruption • Runoff and snowmelt 5. Infrastructure 2. Water demand • National and regional needs • Withdrawals in the US • Withdrawals in the West 6. Solutions? • Water conservation • Water stress and conflict • Water markets 3. Water quality • Desalination • Water quality in streams • Water quality in lakes • Drinking water 1/20/2013 4
- 5. 1. WATER SUPPLY 1/20/2013 5
- 6. Water abounds, but freshwater supply is limited Saline Surface water Atmospheric groundwater and other water 0.22% and saline Freshwater freshwater lakes, 1% Biological 2.5% 1.3% water 0.22% Rivers 0.46% Swamps and marshes 2.53% Groundwater Lakes Soil moisture 30.1% 20.1% 3.52% Oceans Glaciers 96.5% and ice caps Ice and 68.6% snow 73.1% Global water supply Freshwater Surface water and other freshwater Source: Water in Crisis: A Guide to the World’s Fresh Water Resources 1/20/2013 6
- 7. Water is especially precious in the arid West Average annual precipitation (1971 – 2000) 100th Meridian 1/20/2013 7
- 8. Western states see relatively few rainy days Number of rainy days per year NH HI Most WV rainy days VT AK OH CO TX NM Fewest rainy CA days NV AZ 0 20 40 60 80 100 120 140 160 180 Source: NOAA 1/20/2013 8
- 9. Precipitation has been decreasing in parts of the West Changes in annual precipitation, 1959 - 2008 Source: U.S. Global Change Research Program 1/20/2013 9
- 10. Drought has increased in much of the West Observed drought trends, 1958 - 2007 Source: U.S. Global Change Research Program 1/20/2013 10
- 11. Precipitation is expected to decrease in the near future Predicted precipitation changes, 2020 - 2039 vs. 1961 - 1990 Source: Tetra Tech, Natural Resources Defense Council 1/20/2013 11
- 12. Later this century, major seasonal changes are expected Projected precipitation changes: 2080 - 2099 Source: U.S. Global Change Research Program 1/20/2013 12
- 13. Runoff is expected to fall sharply in the Southwest Change in Projected Runoff, 2041-2060 vs. 1901-1970 Source: U.S. Global Change Research Program 1/20/2013 13
- 14. Snowmelt will occur earlier, especially in Northwest Source: The Nature Conservancy 1/20/2013 14
- 15. Earlier peaks will alter dam operations and ecosystems Trends in peak streamflow timing, 2080 - 2099 vs. 1951 - 1980 Difference in days Source: U.S. Global Change Research Program 1/20/2013 15
- 16. 2. WATER DEMAND 1/20/2013 16
- 17. Two measures for national water use Water Withdrawals by Use Water Consumption by Use 8% 4% 3% 8% 12% 41% 39% 85% Irrigation Thermoelectric Domestic Industrial Source: U.S. Geological Survey, National Renewable Energy Laboratory 1/20/2013 17
- 18. Withdrawals are leveling even as population grows 500 350 450 Total withdrawals, billions of gallons/day 300 400 350 250 U.S. population, millions 300 200 250 150 200 150 100 100 50 50 0 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Source: U.S. Geological Survey 1/20/2013 18
- 19. Withdrawals dominated by power and irrigation Water withdrawals in the U.S. (billions of gallons/day) 500 Aquaculture 450 Commercial 400 350 Mining 300 Livestock 250 Self-supplied domestic 200 Self-supplied 150 industrial Public supply 100 50 Irrigation 0 Thermoelectric 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 power Source: U.S. Geological Survey 1/20/2013 19
- 20. Public supply withdrawals are steadily increasing Water withdrawals in the U.S. (billions of gallons/day) 90 Note: irrigation and thermoelectric power 80 removed Aquaculture 70 Commercial 60 Mining 50 Livestock 40 Self-supplied domestic 30 Self-supplied industrial 20 Public supply 10 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Source: U.S. Geological Survey 1/20/2013 20
- 21. Irrigation is the top water user in the West Water withdrawals in the West, 2005 Industrial Self- Supplied 0.1% Domestic, Self- Supplied 0.8% Public Supply 10.8% Irrigation 76.2% Thermoelectric 11.8% Mining 0.3% Livestock 0.2% Source: U.S. Geological Survey 1/20/2013 21
- 22. Western states lead the nation in irrigation Total withdrawals for irrigation, 2005 Source: U.S. Geological Survey 1/20/2013 22
- 23. Some Western states are also top groundwater users Source: U.S. Geological Survey 1/20/2013 23
- 24. Nationally, groundwater withdrawals are rising Surface water vs. groundwater withdrawals 500 Withdrawals, Billions of Gallons per Day 450 400 350 300 250 200 150 100 50 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Groundwater Surface water Source: U.S. Geological Survey 1/20/2013 24
- 25. Runoff vs. water use: degree of water stress Source: The Nature Conservancy 1/20/2013 25
- 26. Growth will increase pressure on water supply Projected population change by county: 2000 - 2050 Source: U.S. Global Change Research Program 1/20/2013 26
- 27. Climate change, growth will cause water conflicts Potential water supply conflicts by 2025 Source: Bureau of Reclamation, U.S. Global Change Research Program 1/20/2013 27
- 28. 3. WATER QUALITY 1/20/2013 28
- 29. Major regions in Wadeable Streams Assessment Source: U.S. Environmental Protection Agency 1/20/2013 29
- 30. Western streams top the water quality rankings Biological condition of streams West 45.1% 25.8% 27.4% Plains and Lowlands 29.0% 29.0% 40.0% Eastern Highlands 18.2% 20.5% 51.8% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Good Fair Poor Not Assessed Source: U.S. Environmental Protection Agency 1/20/2013 30
- 31. Major regions in National Lakes Assessment Source: U.S. Environmental Protection Agency 1/20/2013 31
- 32. Western lakes are in poor condition Xeric Western Mountains Good Fair Poor National 0% 20% 40% 60% 80% 100% Percent of Lakes Source: U.S. Environmental Protection Agency 1/20/2013 32
- 33. Degradation of lakeshore habitat threatening lakes 45% 40% 35% 30% Percent of U.S. Lakes 25% 20% 15% 10% 5% 0% Lakeshore Physical Shallow Total Total Lakeshore Turbidity Dissolved habitat habitat water nitrogen phosphorus disturbance oxygen complexity habitat Source: U.S. Environmental Protection Agency 1/20/2013 33
- 34. 4. FRESHWATER HABITAT 1/20/2013 34
- 35. Freshwater ecoregions in the West Source: The Nature Conservancy 1/20/2013 35
- 36. The West has some hotspots for freshwater endemics Source: The Nature Conservancy 1/20/2013 36
- 37. Number of freshwater mammal species Source: The Nature Conservancy 1/20/2013 37
- 38. Number of freshwater bird species Source: The Nature Conservancy 1/20/2013 38
- 39. Even dry areas are home to many amphibians Source: The Nature Conservancy 1/20/2013 39
- 40. Some hotspots for threatened amphibians in the West Source: The Nature Conservancy 1/20/2013 40
- 41. Fewer fish species are present in the West Source: The Nature Conservancy 1/20/2013 41
- 42. The Pacific Northwest has many migratory fish Source: The Nature Conservancy 1/20/2013 42
- 43. Western fish runs suffer significant disruptions Source: The Nature Conservancy 1/20/2013 43
- 44. Invasive species imperil freshwater habitat Source: The Nature Conservancy 1/20/2013 44
- 45. 5. INFRASTRUCTURE 1/20/2013 45
- 46. Water infrastructure is in especially poor shape ASCE infrastructure report card, 2009 Sector Grade Drinking water D- Wastewater D- Dams D- Levees D- Schools D- Roads D- Aviation D Energy D+ Rail C- Public parks and recreation C- Solid waste C+ Source: American Society of Civil Engineers 1/20/2013 46
- 47. Crumbling water works will cost billions to fix Estimated investment need 2010 - 2015 Dams Levees Estimated Actual Spending Inland Waterways Rail American Recovery and Reinvestment Act Energy Hazardous Waste and Solid Waste 5-Year Investment Shortfall Public Parks and Recreation Aviation Schools Drinking Water and Wastewater Transit Roads and Bridges $0 $100 $200 $300 $400 $500 $600 $700 $800 $900 $1,000 Billions Source: American Society of Civil Engineers 1/20/2013 47
- 48. California has the greatest infrastructure need Necessary investment in water infrastructure over 20 years $30,000 $25,000 $20,000 Millions $15,000 Drinking Water Wastewater $10,000 $5,000 $0 Source: American Society of Civil Engineers 1/20/2013 48
- 49. The Southwest badly needs dam repairs Number and percent of dams in need of rehabilitation 180 45% 160 40% 140 35% 120 30% 100 25% 80 20% 60 15% 40 10% 20 5% 0 0% Source: American Society of Civil Engineers 1/20/2013 49
- 50. Price of water continues to climb Source: USA Today 1/20/2013 50
- 51. 6. SOLUTIONS? 1/20/2013 51
- 52. As top user, irrigation has most conservation potential Water withdrawals in the West, 2005 Industrial Self- Supplied 0.1% Domestic, Self- Supplied 0.8% Public Supply 10.8% Irrigation 76.2% Thermoelectric 11.8% Mining 0.3% Livestock 0.2% Source: U.S. Geological Survey 1/20/2013 52
- 53. Conservation strategies for agriculture Potential savings compared to fallowing and land retirement Source: Pacific Institute 1/20/2013 53
- 54. Outdoor use dominates household consumption Average household water use 100% Other Baths Dishwashers Leaks Unknown 90% Faucets 80% Showers Clothes Washers 70% Toilets 60% 50% 40% 30% Outdoor 20% 10% 0% Gallons per capita Source: American Water Works Association 1/20/2013 54
- 55. Reusing greywater can cut residential demand Average indoor residential water use for 12 North American cities Faucets 16% Leaks 14% Greywater: from Clothes Washer bath, shower, and 21% clothes washer. About 40%, or 28 gallons per capita Blackwater: per day. Toilets dishwasher, toilets, Shower 27% etc. account for 17% 28%, or 19.5 gallons per capita per day. Bath 2% Other Domestic 2% Dishwashers 1% Source: American Water Works Association 1/20/2013 55
- 56. Efficient toilets and clothes washers offer big savings Comparison of average daily water use: with and without conservation measures Dishwashers Baths With conservation Without conservation Other Domestic Uses Leaks Faucets Showers Clothes Washers Toilets 0 5 10 15 20 Gallons per capita per day Source: Handbook of Water Use and Conservation 1/20/2013 56
- 57. Distributing toilets is most cost effective option Ordinances Surcharges Classes Source: Water Conservation Alliance of Southern Arizona 1/20/2013 57
- 58. Water markets are already functioning in West Volume of water transfers in the West 3.0 2.5 2.0 Millions of acre-feet 1.5 Sales 1.0 Long-Term Leases 0.5 Short-Term Leases 0.0 Source: Brewer et al. (2007) 1/20/2013 58
- 59. Agriculture is the top source for water transfers Number of water transfers in the West, 1987 - 2005 Environmental to Agricultural Environmental to Urban Environmental to Environmental Urban to Agricultural Urban to Environmental Combination Agricultural to Environmental Urban to Urban Agricultural to Agricultural Agricultural to Urban 0 500 1,000 1,500 2,000 Number of Transfers Source: Brewer et al. (2007) 1/20/2013 59
- 60. California, Arizona, and Idaho lead in water transfers Volume of water transferred by state and transfer type … … NV … Ag to Urban UT Ag to Envir … Ag to Ag Urban to Urban … Urban to Ag CO Urban to Envir TX Combination ID AZ CA 0 2 4 6 8 10 12 Millions of acre-feet Source: Brewer et al. (2007) 1/20/2013 60
- 61. Desalination capacity growing steadily Global cumulative contracted capacity of desalination plants 70 60 Millions of cubic meters per day 50 40 30 20 10 0 Source: Pacific Institute 1/20/2013 61
- 62. Many new desal plants proposed in California Source: Pacific Institute 1/20/2013 62
- 63. Desalination is very energy intensive—and costly Energy intensity of water sources in San Diego County Seawater desalination San Francisco Bay Delta Imperial Irrigation District Colorado River Water bags Local groundwater Recycling Local surface water 0 1000 2000 3000 4000 5000 Energy intensity, kWh/af Source: Pacific Institute 1/20/2013 63
- 64. Conclusion • A limited and unpredictable water supply is one of the defining features of the American West, which faces a water crisis that is being compounded by growth and climate change. • Climate change is expected to make the Southwest even drier and shrink the snowpack in many locations, causing problems for water managers and freshwater ecosystems. • Overall, we’re becoming more efficient in our water use, but total demand continues to rise along with the region’s growing population and energy use. • Although water quality has generally improved, our water infrastructure is crumbling in the West and across the nation. • Looking ahead, water conservation, water reuse, expanded water markets, and desalination are likely to play a role in addressing the challenge of water in the West. 1/20/2013 64
- 65. Download more slides and other libraries ecowest.org Contact us by e-mailing mitch@ceaconsulting.com 1/20/2013 65
- 66. EcoWest advisors Jon Christensen, Adjunct Assistant Professor and Pritzker Fellow at the Institute of the Environment and Sustainability and Department of History at UCLA; former director of Bill Lane Center for the American West at Stanford. Bruce Hamilton, Deputy Executive Director for the Sierra Club, where he has worked for more than 35 years; member of the World Commission on Protected Areas; former Field Editor for High Country News. Robert Glennon, Regents’ Professor and Morris K. Udall Professor of Law and Public Policy, Rogers College of Law at the University of Arizona; author of Water Follies and Unquenchable. 1/20/2013 66
- 67. EcoWest advisors Jonathan Hoekstra, head of WWF’s Conservation Science Program, lead author of The Atlas of Global Conservation, and former Senior Scientist at The Nature Conservancy. Timothy Male, Vice President of Conservation Policy for Defenders of Wildlife, where he directs the Habitat and Highways, Conservation Planning, Federal Lands, Oregon Biodiversity Partnership, and Economics programs. Thomas Swetnam, Regents' Professor of Dendrochronology, Director of the Laboratory of Tree-Ring Research at the University of Arizona, and a leading expert on wildfires and Western forests. 1/20/2013 67
- 68. Contributors at California Environmental Associates Mitch Tobin Editor of EcoWest.org Communications Director at CEA Micah Day Associate at CEA Matthew Elliott Contact us by e-mailing Principal at CEA mitch@ceaconsulting.com Max Levine Associate at CEA Caroline Ott Research Associate at CEA Sarah Weldon Affiliated consultant at CEA 1/20/2013 68
Editor's Notes
- Narrative: Breaking down the complex issue of water in the West is a task unto itself, and in this presentation we’ve organized the metrics into six broad categories. 1) We begin by discussing the West’s water supply—how it is naturally limited, how climate change will continue to alter precipitation patterns, and what all this means for the West’s streams, rivers, and reservoirs.2) Next, we discuss the demand for water: what sectors and users consume and withdraw the most water in the US and the West? Where is there increasing conflict?3) The following section discusses water quality in streams, lakes, and our drinking water.4) Our focus then shifts to the West’s aquatic and riparian habitats and some of the threats to native biodiversity in freshwater systems.5) We provide a brief discussion of the state of our nation’s water works and the steep repair bill facing utilities across the nation.6) Finally, we outline some potential solutions: conserving water and using it more efficiently, using markets to reallocate the supply, and tapping the ocean through desalination.
- Narrative: Let’s begin by discussing the West’s water supply: where our water comes from and how those sources may change in the future. Climate change is expected to make the Southwest drier, and while precipitation is projected to increase in the Pacific Northwest, it will be more likely to fall as rain than snow, causing major changes to the runoff that feeds Western rivers.
- Narrative: Water abounds on Earth, but our freshwater supply is extremely limited. These bars illustrate Earth’s total water distribution. About 97 percent of all water is in the oceans, with freshwater comprising just 2.5% of total water supply. The majorityof this freshwater is locked up in glaciers and icecaps, with most of the remaining freshwater found below our feetas groundwater. Surface and other freshwater (including ice, snow, lakes, and rivers) make up a very small fraction of total freshwater.Source: Igor Shiklomanov’s chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World’s Fresh Water Resources (Oxford University Press, New York).URL: http://ga.water.usgs.gov/edu/earthwherewater.htmlNote:“Glaciers and ice caps” represents semi-permanent storage of freshwater, while “ice and snow” represents seasonally frozen water supply.
- Narrative: Water is an especially scarce resource in the West. This map shows average annual precipitation from 1971 to 2000. As you move from east to west, the climate gets noticeably drier, with the exception of the Pacific Northwest. In the 11 contiguous Western states (Washington, Oregon, Idaho, Montana, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, and California), annual average precipitation is just 18 inches, while the US average is 37 inches.Source: Map from PRISM Oregon State University, precipitation data from NOAA National Climatic Data CenterURL:http://prism.oregonstate.edu/products/viewer.phtml?file=/pub/prism/us_30s/graphics/ppt/Normals/us_ppt_1971_2000.14.png&year=1971_2000&vartype=ppt&month=14&status=final http://www.currentresults.com/Weather/US/average-annual-state-precipitation.php
- Narrative: So how does the West’s precipitation compare with the rest of the country? This graphic displays the states with the highest and lowest number of rainy days (defined as number of days with precipitation 0.01 inch or more). At the extremes, New Hampshire sees the most rainy days (close to every other day), while Arizona sees the fewest (about once every ten days). Not surprisingly, several Western states, including Nevada, California, New Mexico, and Colorado, have the lowest number of rainy days.Source: NOAA Environmental Satellite, Data, and Information ServiceURL: http://www1.ncdc.noaa.gov/pub/data/ccd-data/prge0110.txt
- Narrative: Parts of the West have become even drier over the past fifty years. From 1959 to 2008, US annual average precipitation increased about 5 percent. However, many areas in the West and Southeast experienced a decrease in annual precipitation; Arizona and the Pacific Northwest, for example, havebecome noticeably drier.Source: U.S. Global Change Research Program URL: http://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf
- Narrative: Changes in precipitation are connected to patterns of drought, with some parts of the West experiencing more droughts over time and others less. This map shows trends in end-of-summer drought as measured by the Palmer Drought Severity Index from 1958 to 2007. Hatch marks indicate areas where major trends have occurred; in the West, drought has been on the increase in more areas than it has been on the decline. By contrast, drought in the Northeast has become less common.Source: US Climate Change Science Program, Guttman and QuayleURL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdf
- Narrative: Looking ahead, precipitation is projected to decrease in many regions of the West. This map focuses on the period between 2020 and 2039—not far off from today—and shows a projected decrease in precipitation for large portions of California, Nevada, Utah, and Oregon, and virtually all of Arizona and New Mexico. Regions at lower latitudes, in particular, are expected to get drier, while the Pacific Northwest and Northern Rockies are projected to get wetter. Source: Evaluating Sustainability of Projected Water Demands Under Future Climate Change Scenarios, Tetra Tech/NRDC, July 2010, page 13URL: http://rd.tetratech.com/climatechange/projects/doc/Tetra_Tech_Climate_Report_2010_lowres.pdf
- Narrative: Climate models using a high emissions scenario predict that in the winter and spring, northern areas are likely to get wetter, while southern areas are expected to get drier. In the summer, most regions of the US are expected to get drier. There’s less certainty on where exactly the transition between wetter and drier areas will occur, but the hatched areas indicate where confidence is highest. Source: Global Climate Change Impacts in the United States, US Global Change Research ProgramURL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdf
- Narrative: Add it all up and we’re expecting to see pretty significant declines in runoff, which is the melting snowpack and rainfall that flows into streams, rivers, reservoirs, and the ocean. This map shows projected changes in median runoff for 2041-2060, relative to a 1901-1970 baseline. Hatched areas indicate greaterconfidence due to strong agreement among model projections, while white areas indicate divergence among model projections. We can see that a 10 to 20 percent decline in runoff is expected throughout California, the Great Basin, and the Upper Colorado River, as well as along the Rio Grande. Source: U.S. Global Change Research Program, Milly et al, page 45URL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdfNotes: Results are based on emissions in between the lower and higher emissions scenarios.
- Narrative: The West’s snowpack and the timing of the spring and summer snowmelt are critical ingredients in the region’s water supply. For many rivers in the West, spring and summer runoff contributes 50 – 80% of annual flow. The timing of this snowmelt discharge ranges from as early as February in some of the rivers along the Pacific coast to as late as June for rivers in the Rocky Mountains. Over the next thirty years, however, the surge of snowmelt that feeds Western rivers is expected to come dramatically earlier. This map shows the projected change in peak snowmelt timing from 1975 to 2040, by freshwater ecoregion. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=7819b679e4104e46952ce3a79e0cd7b5
- Narrative: These changes in snowmelt timing mean that peak streamflow will also occur earlier. This map shows projected changes in snowmelt-driven streams by 2080-2099, compared to 1951-1980, under a higher scenario for greenhouse gas emissions. An earlier snowmelt runoff poses difficulties for water supply management and ecosystem health. Dam managers will have to alter their operations and species will have to adapt to new seasonal patterns.Title: Trends in peak streamflow timing, 2080 – 2099 vs. 1951 - 1980Source: U.S. Global Change Research Program, Stewart et al.URL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdf
- Narrative: We know that the supply of water is naturally limited in most parts of the West and that there aren’t many sources that haven’t been tapped yet. But where does all that water go? In this section we discuss water demand and the changing patterns in how we use water in the West. Irrigation remains the top water user in the West, but municipal demand is increasing as cities continue to grow. The energy sector is a major water user (and plenty of energy is required to pump, move, and treat water).
- Narrative: When examining water use, it is important to distinguish withdrawals from consumption. Water withdrawals refer to water diverted from a surface water or groundwater source. In many cases, water withdrawals are returned to the environment for future use. Consumptive water use, on the other hand, refers to water that is permanently removed from its source—in other words, water that is no longer available because it has evaporated, been incorporated into products or crops, been consumed by people or livestock, or otherwise been removed from the immediate water environment. This distinction becomes especially apparent when examining water use by thermoelectric power plants; while power plants account for 39% of all withdrawals, they consume just 3% of all water. Nationally, irrigation for agriculture accounts for 85 percent of consumptive water use.Source: Consumptive Use for U.S. Power Production, Appendix AURL: http://www.nrel.gov/docs/fy04osti/33905.pdf
- Narrative: Between 1950 and 1980,water use in the United States steadily increased. During this time, the expectation was that population growth would continue to drive an increase in water withdrawals, but the level declined shortly after 1985 and has since remained relatively stable despite a growing population. One reason the overall per capita rate has been steady is that power plants have shifted to recirculating technologies that withdraw less water. There have also been gains as farmers have shifted from flood to sprinkler irrigation. If you just look at domestic water use, the per capita rate declined slightly from 101 gallons a day in 1995 to 99 in 2005, but the rate varied from 51 gallons a day in Maine to 189 in Nevada.Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/
- Narrative: This chart depicts total water withdrawals in the US by water use from 1950 to 2005. Thermoelectric power withdraws more water than any other use, with irrigation in a close second. Overall, withdrawals peaked in 1980 and have over the past 25 years hovered around 400 billion gallons per day.Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/
- Narrative: This graph displays the same water data as the previous slide, but removes thermoelectric power and irrigation. While total withdrawals for most uses have leveled off, there has been a steady increase in water use for public supply (utilities delivering water to homes and businesses). In fact, public-supply withdrawals more than tripled during this 50-year period and increased about 2 percent from 2000 to 2005. This increase reflects the trend towards urbanization over the last 50 years; the percentage of the population served by public suppliers increased from 62 percent in1950 to 86 percent in 2005. Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/Notes: Values for aquaculture, commercial, and mining are included in self-supplied industrial for the years 1950 - 1980
- Narrative:Focusing on the West, we see that irrigation accounts for the vast majority of withdrawals. Irrigation has been by far the largest water user since USGS began collecting data in 1950. Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/
- Narrative: In 2005, the majority of withdrawals (85 percent) and irrigated acres (74 percent) were in the 17 coterminous Western states. California, Idaho, Colorado, and Montana combined accounted for 49 percent of the total irrigation withdrawals and 64 percent of surface-water irrigation withdrawals. Source: US Geological Survey Water Use in the US 2005URL: http://pubs.usgs.gov/circ/1344/pdf/c1344.pdf
- Narrative: Similarly, many Western states were also the top groundwater users in 2005. The top three consumers of water for agriculture (California, Idaho, and Colorado) were also among the states consuming the most groundwater. Source: US Geological Survey Water Use in the US 2005URL: http://pubs.usgs.gov/circ/1344/pdf/c1344.pdf
- Narrative: While surface water withdrawals have leveled off over the past half-century, USGS data shows some increase in the use of groundwater since 1950. Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/
- Narrative: So what do the West’s water use trends mean for the future availability of water? This map displays water availability by ecoregion based on the ratio of runoff to water use—essentially the supply of surface water vs. the demand for those resources. This calculation does not account for the use of water from alternate sources such as groundwater, desalination, or reuse of wastewater. Nevertheless, huge regions of the West are classified as having some degree of water stress, with the most threatening imbalances occurring in southern Arizona, central and northern California, Nevada, and the western high plains. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=04aad4fac63e47248b84d5fe2c6d5209Notes:Data derived from:Alcamo, J., P. Döll, T. Henrichs, F. Kaspar, B. Lehner, T. Rösch, and S. Siebert. 2003. Development and testing of the WaterGAP 2 global model of water use and availability. Hydrological Sciences Journal 48, no. 3: 317-338.Döll, P., F. Kaspar, and B. Lehner. 2003. A global hydrological model for deriving water availability indicators: Model tuning and validation. Journal of Hydrology 270: 105-134.
- Narrative: Another factor increasing Western water demand—and particularly demand for public supply—is population growth. This map shows projected population growth from 2000 – 2050. Many counties in the West are expected to experience significant growth, with population doubling in many counties in California, Arizona, and Nevada, among other states.Source: US Climate Change Science ProgramURL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdf
- Narrative: With increasing demand and decreasing supply, water conflicts are expected to multiply in the coming years. This map from the US Bureau of Reclamation shows regions in the West where water supply conflicts are likely to occur by 2025. The assessment was based on a combination of factors, including population trends and endangered species’ water needs. The red zones are where the conflicts are most likely to occur. Areas where the potential for conflict is greatest include the San Joaquin River and Bay Delta in California, the Great Salt Lake in Utah, the lower Colorado River, the Mogollon Rim area of Arizona, the Rio Grande River, and the Colorado Front Range. Source: US Climate Change Science Program/ US Bureau of ReclamationURL: http://downloads.climatescience.gov/usimpacts/pdfs/climate-impacts-report.pdf http://downloads.climatescience.gov/usimpacts/pdfs/water.pdf
- Narrative: Let’s move on from water supply and demand to talk about the quality of our water. In general, water quality has improved in the United States thanks to laws like the Clean Water Act. We no longer have rivers on fire and we generally don’t dump raw sewage into streams anymore. Measuring the quality of the West’s water is actually somewhat difficult because there aren’t a lot of good sources of high-level data, but here’s what we’ve found.
- Narrative: While the USGS and EPA closely monitor water quality at a watershed level, inconsistent reporting standards have led to a dearth of information on water quality trends in the United States. In an attempt to fill this gap, the EPA in 2006 launched the National Aquatic Resource Survey, an examination of water quality in the nation’s streams, lakes, coastal areas, and wetlands. The map above displays the three major regions for which the EPA studies have aggregated data: the Eastern Highlands, the Plains and Lowlands, and the West. Source: Wadeable Streams Assessment, EPA, 2006URL: http://water.epa.gov/type/rsl/monitoring/streamsurvey/upload/2007_5_16_streamsurvey_WSA_Assessment_May2007-2.pdf
- Narrative: Of the three major regions examined in the EPA’s study, the West was in the best biological condition, with 45% of stream length rated good. Source: Wadeable Streams Assessment, EPA, 2006URL: http://water.epa.gov/type/rsl/monitoring/streamsurvey/upload/2007_5_16_streamsurvey_WSA_Assessment_May2007-2.pdf Notes: These results were based on a macroinvertebrate index of biological condition that weighs several factors, including taxonomic richness, habit and trophic composition, and sensitivity to human disturbance. EPA is currently analyzing the second round of the streams survey, which will also include data on rivers. These results will be available in May of 2012.
- Narrative: For its assessment of water quality in lakes, the EPA reported data for nine regions. In the West, these include the drier xeric region (displayed in orange) and the Western mountains (displayed in green). The xeric ecoregion is comprised of a mix of physiographic features. The region includes the flat to rolling topography of the Columbia/Snake River Plateau; the Great Basin; Death Valley; and the canyons, cliffs, buttes, and mesas of the Colorado Plateau. Source: Environmental Protection Agency, National Lakes AssessmentURL: http://water.epa.gov/type/lakes/upload/nla_newlowres_fullrpt.pdf
- Narrative: While the majority of the nation's lakes and the lakes of the Western mountains are relatively healthy,nearly half of the lakes in the xeric (dry)ecoregion arein poor condition.Source: Environmental Protection Agency, National Lakes AssessmentURL: http://water.epa.gov/type/lakes/upload/nla_newlowres_fullrpt.pdf
- Narrative: This graphic illustrates key stressors affecting the biological condition in lakes. Specifically, it shows the proportion of poor biological conditions that could be improved if a stressor were eliminated (e.g., 43% of U.S. lakes' biological conditions would improve if their lakeshore habitat were improved). Nationally, the most widespread stressors are those that affect the shoreline and shallow water areas, which in turn can affect biological condition. The most widespread of these is the alteration of lakeshore habitat, measured by the amount and type of shoreline vegetation. According to the EPA, poor lakeshore habitat conditions pose a serious threat to lakes, suggesting the need for stronger management of shoreline development.Source: Environmental Protection Agency, National Lakes AssessmentURL: http://water.epa.gov/type/lakes/upload/nla_newlowres_fullrpt.pdf
- Narrative: We have another presentation available on ecowest.org that explores biodiversity in the West and discusses both aquatic and riparian ecosystems. Here we offer a couple of summary slides on freshwater habitat in the West.
- Narrative: This close-up of the West shows its two-dozen or so freshwater ecoregions, as defined by The Nature Conservancy. This is the unit of analysis we’ll be using in the next few slides. The geographic definitions of freshwater ecoregions don’t always line up with the boundaries of river basins. The Colorado River Basin, for example, includes the Colorado, Bonneville, Vegas-Virgin, and Gila freshwater ecoregions. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xmlNotes: “Freshwater ecoregions divide the world into regions that contain similar freshwater species. Each of the world’s 426 freshwater regions contains a distinctive suite of fish species, other aquatic species, and freshwater habitats.”
- Narrative: One measure of biological diversity is the number of endemic species that are found in a given location but nowhere else on the planet. In the United States, freshwater endemism is greatest in Virginia, the Carolinas, and Georgia; out West, hotspots include California, Oregon, Utah, and Arizona.Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=c36f49c00c8d4494986befe0ec1e39d3Notes: The map of the number of freshwater endemic species shows the number of endemic fish, freshwater turtles, crocodiles, and amphibians found in each freshwater ecoregion. To calculate the total number of endemic species by ecoregion, we simply added the number of endemic species in these four taxonomic groups. Fish endemics are from Abell et al. (2008). Extirpated fish species are included in these tallies, but resolved extinct species, as determined by the Committee on Recently Extinct Organisms, and introduced species are excluded. Data on amphibian species were generated from distribution maps for 5,640 amphibian species gathered by the Global Amphibian Assessment (IUCN et al. 2006). Data on freshwater turtles were generated from species distribution maps provided by Dr. Kurt A. Buhlmann, the Savannah River Ecology Laboratory, University of Georgia, United States; and the International Union for Conservation of Nature–Species Survival Commission (IUCN-SSC) and Conservation International/Center for Applied Biodiversity Science (CI/CABS) Global Reptile Assessment (preliminary results). For both amphibians and turtles, species distribution maps were used to determine endemism by ecoregion. If at least 90 percent of a species’ range occurred in only one ecoregion, that species was said to be endemic. Some ecoregions with a long and narrow shape may have an overestimation of species given the way the range polygons were drawn.Our primary data sources for the maps were the following:Abell, R., M. L. Thieme, C. Revenga, M. Bryer, M. Kottelat, N. Bogutskaya, B. Coad, et al. 2008. Freshwater ecoregions of the world: A new map of biogeographic units for freshwater biodiversity conservation. BioScience 58, no. 5: 403–414.Buhlmann, K. A., T. B. Akre, J. B. Iverson, D. Karapatakis, R. A. Mittermeier, A. Georges, A. G. J. Rhodin, P. P. van Dijk, and J. W. Gibbons. 2007. A global analysis of tortoise and freshwater turtle distributions. Data from the preliminary results of the Global Reptile Assessment. International Union for Conservation of Nature–Species Survival Commission (IUCN-SSC), Conservation International/Center for Applied Biodiversity Science (CI/CABS), and Savannah River Ecology Laboratory, University of Georgia, Athens, Georgia, USA.International Union for Conservation of Nature (IUCN), Conservation International, and NatureServe. 2006. Global Amphibian Assessment. Available at www.iucnredlist.org/amphibians. Digital media.
- Narrative: In the United States, most areas have between four and eight freshwater mammal species, but there are upwards of 20 in the Pacific Northwest, parts of the Midwest, and along the eastern seaboard. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=fe75950e6b524b548d30053861d884beNotes: Freshwater mammals include aquatic or semiaquatic species that spend a considerable amount of time in freshwater to feed and that usually live in the riparian vegetation close to rivers, lakes, marshes, swamps, and other freshwater habitats. We used species range maps, visual assessment of locations based on literature descriptions, and expert opinion to assign mammal species presence to ecoregions. Range species maps and distribution information for individual species obtained from multiple sources and literature sources were used to determine whether a species is considered a freshwater mammal. Rodents make up at least 50 percent of all mammal species, and this percentage is probably underestimated given that every year more than thirty to forty new rodent species are recognized. In general, rodents are a poorly studied group; therefore, the number of species considered “freshwater rodents” in this data set is underestimated, and the species numbers are likely to be much higher.
- Narrative: In the United States, Texas is the state with the most freshwater bird species, but at least 60 species are found in nearly every part of the country.Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=eb185e881fe54f3ea40977cfac8bf927Notes: Freshwater obligate birds include those species that need freshwater habitats for breeding (e.g., ducks, herons) or feeding (i.e., birds that depend almost exclusively on food found in freshwater habitats, such as freshwater fish, mollusks, and crustaceans). In all, 815 bird species were found to meet this criterion globally, with almost all bird families represented. We mapped freshwater bird species to freshwater ecoregions. Literature sources were used to determine whether a species was considered a freshwater bird.
- Narrative: The Southeast United States has the greatest number of amphibian species and an especially large number of salamanders. There aren’t as many amphibian species out West, but there are still plenty even in places that aren’t especially wet, such as the Colorado Plateau and Mojave Desert. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=08a1ba612a744b88bb5c37c7da4d6975Notes: We calculated the number of amphibian species per freshwater ecoregion using species range maps of the Global Amphibian Assessment (GAA, www.iucnredlist.org/amphibians) (IUCN et al. 2006). The 2006 GAA assessed 5,918 amphibian species and provided distribution maps for 5,640 of those species. When a range overlapped several ecoregions, we counted species as present in all those ecoregions that had part of the range. This may have resulted in an overestimate of species numbers in some ecoregions, especially those that are long and narrow in shape.Distribution maps from the GAA represent the “extent of occurrence” for each species—that is, the area contained within the shortest continuous imaginary boundary, which can be drawn to encompass all the known, inferred, or projected sites of present occurrence of a taxon. Because of the conservative approach taken in the GAA to mapping species, the ranges for many species are likely to be minimum estimates. The GAA followed a rule of allowing interpolation of occurrence between known locations if the ecological conditions seem appropriate, but not permitting extrapolation beyond known locations. Some species are therefore almost certain to occur much more widely than the GAA has mapped. Because of this, some regions were recorded as having much lower numbers. Finally, the percentage of data-deficient species (23.4 percent) were very high compared to other taxa in the GAA.Data derived from: International Union for Conservation of Nature (IUCN), Conservation International, and NatureServe. 2006. Global Amphibian Assessment. www.iucnredlist.org/amphibians. Digital media.
- Narrative: In the United States, Texas has the most threatened amphibians. There are three to seven such species in California, Oregon, and the Four Corners states.Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=461e58214aa54ad79382066ab829c05fNotes: We generated the map of the number of freshwater amphibian species per ecoregion that are threatened with extinction using data from the Global Amphibian Assessment (GAA) (IUCN et al. 2006). The GAA assessed the conservation status of 5,918 amphibian species, and we analyzed the subset of 4,035 that depend on freshwater during some stage of their life cycle. Strictly arboreal species that do not require freshwater for their larval stage, species that develop directly from eggs without a larval stage, as well as a few live-bearing species were excluded from this analysis. As of 2006, 1,356 freshwater amphibians were considered threatened. It is important to note, however, that for 1,427 amphibian species, there were insufficient data to assess their conservation status—these are classified by the GAA as “data deficient.” Therefore, these estimates for threat are conservative.Data derived from IUCN, Conservation International, and NatureServe.
- Narrative: This map illustrates the number of fish species by freshwater ecoregion. Areas around the Mississippi River and its tributaries harbor the most freshwater fish species, in some cases five times as many as in Western ecoregions.Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xmlhttp: //app.databasin.org/app/pages/datasetPage.jsp?id=4f8f2f8e3ace42dca7141ca7781c0e4fNote: For more information on freshwater habitat, see the Biodiversity slide deck.
- Narrative: If we’re looking at the number of migratory fish species, however, the Pacific Northwest has relatively high diversity. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=61528bc77dce4fada2a7610dbc1ca2fcNote: For more information on freshwater habitat, see the Biodiversity slide deck.
- Narrative: In the United States, which has nearly 80,000 dams, virtually all ecoregions have seen their fish runs significantly disrupted, making it impossible for species to follow their natural movement patterns. In the West, the problem is especially serious along the Columbia and Colorado Rivers, both of which have major hydroelectric dams. Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=b8b04bdfd89b4647bf64c92e615cfea1Note: For more information on freshwater habitat, see the Biodiversity slide deck.
- Narrative: Harmful invasive species are present throughout the country, with the greatest number found around the Great Lakes and in the Northeast.Source: Hoekstra et al. The Atlas Of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Berkeley: University of California Press. 2010URL: http://www.nature.org/ourscience/sciencefeatures/conservation-atlas.xml http://app.databasin.org/app/pages/datasetPage.jsp?id=11a22d0ce62142258baaa1cbaf520fb2Note: For more information on freshwater habitat, see the Biodiversity slide deck.
- Narrative: The nation’s water works—dams, levees, aqueducts, sewage plants—have come a long way over the past century. They’re a major reason why we’ve been able to settle arid parts of the West and clean up many rivers and streams. But as with the rest of the country’s infrastructure, many elements are in disrepair. Fixing the nation’s water works will cost tens of billions of dollars.
- Narrative: Put simply, our nation’s infrastructure is crumbling. When engineers grade the various sectors of infrastructure, none of them do very well, but elements of our water works—dams, levees, and sewage plants—score particularly poorly.Source: American Society of Civil Engineers, Infrastructure Report Card 2009URL: http://www.infrastructurereportcard.org/
- Narrative: The American Society of Civil Engineers projects that we will need an additional $108 billion dollarsover the next five years in order to comply with existing and future federal regulations for drinking water and wastewater. Source: American Society of Civil Engineers, Infrastructure Report Card 2009URL: http://www.infrastructurereportcard.org/
- Narrative: Looking at the investments needed to improve water infrastructure, California comes out on top for both drinking and wastewater systems. Source: American Society of Civil Engineers, Infrastructure Report Card 2009URL: http://www.infrastructurereportcard.org/
- Narrative: Dams in the Southwestern states are most in need of repairs. The blue bars show the number of dams in need of rehabilitation in each state and the orange squares show the percentage of each state’s dams that need this work.Source: American Society of Civil Engineers, Infrastructure Report Card 2009URL: http://www.infrastructurereportcard.org/
- Narrative: Rising infrastructure costs are a major reason why water prices are continuing to climb. This graphic shows that water bills increased faster than natural gas or electricity costs for American consumers between 2000 and 2012. Many experts believe that water rates will keep going up in the West as utilities struggle to find new supplies in response to the increasing demands of a growing population. Higher water prices could also make conservation measures more attractive to individuals, businesses, and water providers.Source: USA TodayURL: http://www.usatoday.com/story/money/business/2012/09/27/rising-water-rates/1595651/Notes: A USA TODAY study of residential water rates over the past 12 years finds that crumbling infrastructure is forcing repairs from coast to coast, with costs more than doubling in 1 of 4 localities.
- Narrative: In this final section, we discuss some water management strategies that are meant to address the crisis in the West, and elsewhere. This isn’t an exhaustive list, but these three strategies are among the most important: 1) conserving water and using it more efficiently; 2) using markets to transfer water from low- to high-value uses; and 3) desalination of seawater to create new potable supplies.
- Narrative: Let’s start with conservation. As we saw earlier, irrigation uses the vast majority of water in the West. For that reason, many researchers and nonprofit organizations have focused on ways to increase water efficiency in agriculture. Source: US Geological Survey Water Use in the US 2005URL: http://water.usgs.gov/watuse/
- Narrative: This graphic shows some of the possible conservation strategies and how they measure up compared to fallowing the land or retiring it from agriculture. Source: More With Less: Agricultural Water Conservation and Efficiency in California, Pacific InstituteURL: http://www.pacinst.org/reports/more_with_less_delta/index.htmNotes: According to the report, “smart irrigation scheduling provides a means to evaluate and apply an amount of water sufficient to meet crop requirements at the right time. Despite the promise of irrigation scheduling and other new technologies, California’s farmers still primarily rely on visual inspection or personal experience to determine when to irrigate. Soil or plant moisture sensors, computer models, daily evapotranspiration reports, and scheduling services, which have long been proven effective, are still fairly uncommon, suggesting there is significant room for improvement.”
- Narrative: Municipal water use has been growing faster than other sectors, so when it comes to conservation, it also makes sense to focus on water use in the home and businesses. In the US, household water use averaged 172 gallons per person per day in 2005. Nearly 60 percent of water use occurred outside of the home for watering lawns, irrigating landscaping, washing cars, filling pools, and the like. Source: American Water Works AssociationURL: http://www.drinktap.org/consumerdnn/Home/WaterInformation/Conservation/WaterUseStatistics/tabid/85/Default.aspxNotes: Original study: Residential End Uses of Water (Denver, Colo.: Water Research Foundation, 1999).
- Narrative: Inside the home, toilets consume about one quarter of all water, clothes washers one fifth. It’s important to note that leaks account for 14 percent of all water use. Another opportunity for water conservation is the use of greywater, or recycled water used twice in the home. Water from baths, showers, and clothes washers can be used for outdoor irrigation, thereby reducing a household’s demand. This graphic shows that greywater accounts for an average of 40 percent of the water used by residents in 12 North American cities. There’s another category, known as blackwater, that includes water from dishwashers and toilets, but that source is too contaminated for immediate use outdoors. On a larger scale, many municipalities in the Southwest reuse their effluent to irrigate turf and some are considering treating the sewage to drinking water standards and delivering it to customers. Source: White Paper on Graywater, Bahman SheikhURL:http://www.awwa.org/files/Resources/Waterwiser/references/PDFs/GraywaterFinal%20Report2010.pdf
- Narrative: Inside the home, a typical homeowner can reduce water consumption by about 30% by implementing conservation measures, such as installing more efficient fixtures and checking for leaks, to say nothing of the savings associated with behavior changes, such as taking shorter showers. Source: Amy Vickers, Handbook of Water Use and Conservation, 2001.URL: http://www.waterplowpress.com/info.html
- Narrative: On average, it costs more to conserve water through audits, device giveaways, washing machine rebates, and landscape conversion than through other conservation measures, such as progressive rate structures and ordinances. Toilet distribution programs showed the highest savings per participant on average and the highest persistence in water savings of all the programs analyzed.Source: Evaluation and Cost Benefit Analysis of Municipal Water Conservation Programs, Water Conservation Alliance of Southern ArizonaURL: http://www.watercasa.org/research/ecoba/
- Narrative: Let’s move on to another potential solution to the imbalance between water supply and demand in the West: shifting water uses among sectors, especially from low-value agricultural uses to cities. Water markets exist where water users voluntarily agree to buy or sell access to new supplies. These sorts of transfers have been taking place for years, with the majority of volume contracted under short-term leases. Water sales—or the permanent reallocation of water rights—actually account for sixty-seven percent of all transactions, but just thirteen percent of the water transferred. To contextualize the total volume, the cumulative volume of water transferred since 1987 amounts to about ten times the annual flow of the Colorado River.Source: Jed Brewer, Robert Glennon, Alan Ker, and Gary Libecap. Transferring Water in the American West: 1987 - 2005, 40 Univ. Mich. J.L. Reform 1021 (2007) URL: http://www2.bren.ucsb.edu/~glibecap/MichiganLawReform.pdfNotes:For context, an acre-foot is roughly the volume of water used in one year by an average suburban family household. (http://dnrc.mt.gov/wrd/water_rts/wr_general_info/wrforms/627.pdf)
- Narrative: This graph shows the number and source of water transfers in the West. Agriculture is the source of most transferred water,which is not surprising given that agriculture accounts for approximately 80 percent of consumptive water use in the West. Agriculture-to-urban exchanges are the most numerous, with fifty-six percent of transfers and eighteen percent of all water transferred. Urban-to-environmental and combination exchanges also involve considerable amounts of water. Urban-to-agriculture, environmental-to-agriculture, environmental-to-urban, and environmental-to-environmental exchanges are comparatively unimportant.Source: Jed Brewer, Robert Glennon, Alan Ker, & Gary Libecap. Transferring Water in the American West: 1987 - 2005, 40 Univ. Mich. J.L. Reform 1021 (2007) URL: http://www2.bren.ucsb.edu/~glibecap/MichiganLawReform.pdf
- Narrative: A couple of states are responsible for most water transfers in the West. Arizona accounts for53 percentof agriculture-to-agriculture and 58 percent of urban-to-urban water transactions. California and Idaho dominatethe agriculture-to-environmental category. Water transfers are comparatively rare in Montana, Nevada, Utah, Washington, and Wyoming, regardless of transfer classification.Source: Jed Brewer, Robert Glennon, Alan Ker, & Gary Libecap. Transferring Water in the American West: 1987 - 2005, 40 Univ. Mich. J.L. Reform 1021 (2007) URL: http://www2.bren.ucsb.edu/~glibecap/MichiganLawReform.pdf
- Narrative: Another often-mentioned solution to the West’s water dilemma is desalination of seawater. In this chart, we see the cumulative total of global desalination capacity, which has been steadily rising over the past two decades.Source: “Desalination, With A Grain of Salt: A California Perspective.” Heather Cooley, Peter H. Gleick, Gary Wolff, Pacific Institute,June 2006.URL: http://www.pacinst.org/reports/desalination/desalination_report.pdf
- Narrative: New desalination plants are being proposed and built along the California Coast. This graphic shows what was proposed in 2006, but not all of these plants have been built. Source: “Desalination, With A Grain of Salt: A California Perspective.” Heather Cooley, Peter H. Gleick, Gary Wolff, Pacific Institute. June 2006URL: http://www.pacinst.org/reports/desalination/desalination_report.pdf
- Narrative: While the capacity of desalination plants continues to grow, this water supply solution is an expensive one, mainly due to its high energy consumption. All of our major water sources require some amount of energy, but desalination is typically at the top of the list when it comes to energy intensity. As an example, this graphic illustrates the energy requirements of the water supply options in San Diego County. Seawater desalination would require even more energy than moving water hundreds of miles from the San Francisco-Bay Delta to Southern California. There are also major concerns related to the disposal of the reject brine stream and the impact of desalination on marine and coastal ecosystems. But because freshwater is so limited in the West, some communities along the coast feel they have no choice but to explore desalination.Source: “Desalination, With A Grain of Salt: A California Perspective.” Heather Cooley, Peter H. Gleick, Gary Wolff, Pacific Institute. June 2006URL: http://www.pacinst.org/reports/desalination/desalination_report.pdf