05_WaterSupplies

05_WaterSupplies - Water Supplies and Global Change - ESM...

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Unformatted text preview: Water Supplies and Global Change - ESM 203 - 1 Water for Life Decade - 2005 to 2015 U.N. initiative motivated by the following: 1 in 6 live w/o access to safe drinking water 2.4 billion people lack access to adequate sanitation water related diseases kill a child every 8 seconds 2 *Open sewer in a Nairobi slum. Click on image for more on the Water for Life Decade. Where is Earth's freshwater? Oceans Ice and snowpacks Groundwater (750-4000m) Groundwater (<750m) Lakes Soil Atmosphere Rivers Biosphere 97.2% 2.0 0.4 0.3 0.01 0.005 0.001 0.0001 0.00004 3 Read: Black, P.E. On the critical nature of "useless" resources; Water Resources Bulletin (1995) Where is the renewable freshwater? (precipitation = runoff + ET) Region River Runoff (km3/yr) 3,240 14,550 4,320 6,200 10,420 1,970 Share of global R (%) Share of global population (%) 13 60 12 8 6 0.5 global R/ global pop. 0.6 0.6 0.9 1.9 4.3 10 Europe Asia Africa N/C America S. America Australia 8 36 11 15 26 5 Source: Postel et al., Science, 1996 4 Global Water Use Gross use - total volume required for some purpose. Usable many times if purified, naturally or technologically Consumptive use --- made unavailable by evaporation 5 Global Water Use Sector Agriculture Industry (incl. power) Municipalities Reservoir losses Subtotal Instream flow needs Total as % of "available runoff" Projections for 2025 Gross use (km3/yr) 2880 975 300 275 4430 2350 54% 70% 6 Source: Postel et al., Science, 1996 Consumptive use (km3/yr) 1870 90 50 275 2285 0 (?) 18% % Consumption 65 9 17 100 How is water used across the globe? Source: Vorosmarty et al., Science, 2000 7 Factors affecting runoff use Moving freshwater from regions of surplus to regions of deficit. "In California, water doesn't flow downhill; it flows toward money." Great investment is needed to construct, operate, and maintain dams and pumps. Regulation of flow by dams worldwide ~3500 km3/yr out of a total "available" runoff of ~ 12,500 km3/yr (Postel et al, 1996, Science). China is considering a $7 billion investment to transfer water from the flood prone south to the drought stricken north. *Click on image for more from the BBC. California's water projects capture enough water to supply 8 cities the size of New York City. *More on the state's water projects later. "The only matter that could take Egypt to war again is water" (Anwar Sadat1979). *Click on image for more from the BBC. 8 Factors affecting runoff use Human society has become the equivalent of a geophysical [Earth-scale] process in affecting water availability through: Climate change (variable but still uncertain degree) Area of land occupied and vegetation cover altered Size of populations and intensity of use by various technologies increasing Expectations rising w.r.t. to lifestyle and health Abstraction of water from usable category for various uses and for various time scales because of pollution Geopolitical issues ("You ain't havin' my water!") 9 Options for increasing available runoff Humans currently consumptively use ~23% of total "available runoff" (Postel et al., Science, 1996) Options for increasing total available runoff: Increase reservoir storage reservoirs (New construction mainly in frontier regions of development, but may have to change. 885 large dams/yr 1950-1985; now `only' 500/yr and meeting resistance) Inter-basin transfers (Colorado, Sacramento, Yangtze) Induced groundwater recharge of flood runoff (Kern Water Bank) Ocean desalination (e.g. Santa Barbara?) Technical efficiencies in irrigation Retirement of marginal lands from irrigated agriculture. Climate change in some areas (but get less runoff in other areas) 10 The California Case Study *The Sacramento River, which delivers over 30% of California's water. Click on the image to learn more about California's State Water Project. 11 Where's California's rainfall? Source: http://www.californiaweekly.com/precipitation_ca.htm 12 Where's California's runoff? 22.4 MAF 7.9 MAF 3.3 MAF Total natural runoff per year = 70.8 million acre feet 13 Where's California's farmland? California's agricultural production is worth nearly 33 billion dollars Nearly 30% of California's land is farmed. 14 Where do Californians live? Nearly 12% of the total population of the U.S. lives in California. 15 How much water do people consume? The average person requires a minimum of 13 gallons of water per day.* Californians use an average of 137 gallons per day. 6 106 Historical Water Consumption by California's Population y = -1.3422e+08 + 69701x R2= 0.99608 Water Consumption (acre feet) 5 106 4 106 W at er U se Proj ect ion f or Calif ornia Year Usage ( Acr e Feet ) % of Tot al Runoff 2003 5 ,5 1 4 ,6 2 4 7 .8 2010 5 ,8 7 9 ,0 1 0 8 .3 2025 6 ,9 2 4 ,5 2 5 9 .8 2050 8 ,6 6 7 ,0 5 0 1 2 .2 3 106 Source: CA Dept. of Finance 2 106 1 106 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year *Read: Gleick, P.H. Basic water requirements for human activities: meeting basic needs. Water International (1996). 16 Characteristics of California 1. Greatest precipitation in north. 2. Greatest runoff in north. 3. Most farmland in south. 4. Greatest population in south. About 75% of water demand originates south of Sacramento. Over 75% of the water supply is located north of Sacramento. 17 Interbasin Transfers of Water From Carl, D. Introduction to Water in California. 18 The Major Redistributions 1. State Water Project (SWP) Moves water from the Feather River watershed in the Sacramento Valley to urban and industrial consumers. More than 67% of all Californians receive some of their water from the SWP. Between 2.3 and 4.2 MAF are delivered by the SWP. Consists of 29 dams, 18 pumping plants, 5 hydroelectric power plants, and 600 miles of canals and pipelines. 19 From Carl, D. Introduction to Water in California. The Major Redistributions 1. State Water Project (SWP) From the SF Delta, water is continuously pumped uphill. At the Edmonston Pumping Plant, water is lifted 1,926 feet over the Tehachapi Mountains. The SWP is California's largest energy consumer. Although hydroelectric power generated by SWP supplies 5.8 kilowatt-hours per year, it is only 75% of the power required to pump water to Southern California. 20 From Carl, D. Introduction to Water in California. The Major Redistributions 2. The Central Valley Project (CVP) Conceived to irrigate 3 million acres of the southern Central Valley (only 15% of the water is used for urban/industry). It stores 7 MAF or 17% of the state's developed water. The CVP dams and diverts water from 5 major rivers: Trinity River (Trinity Dam), Sacramento River (Shasta Dam), American River (Folsom Dam), Stanislaus (New Melones Dam), San Joaquin River (Friant Dam). 21 The Major Redistributions From Carl, D. Introduction to Water in California. 22 The Major Redistributions 3. Colorado River Delivery Systems Supplying up to 4.4 MAF per year, the Colorado River supplies 12% of California's developed water; 25% of this water is used for urban/industry. The Colorado River supplies ~60% for the SoCal Metropolitan Water District Over half a billion dollars have been allocated to the Bureau of Reclamation to mitigate the effects of dams and diversions on habitat in the Colorado River 23 From Carl, D. Introduction to Water in California. The Major Redistributions 1. Los Angeles Aqueduct The first major long-range water project in CA, completed in 1913. To obtain Owens River water, L.A. purchased 98% of all private land in Owens Valley. The aqueduct supplies an average of 400,000 AF per year. 24 From Carl, D. Introduction to Water in California. Image of the Owens Lake bed. Ramifications of Interbasin Redistribution 1. 2. 3. 95% of California's original wetlands are gone. 89% of its riparian woodlands no longer exist. About 1400 dams convert rivers into reservoirs; 600 river miles have been flooded. Dams are major obstacles to the migration of salmonids. Dams alter the sediment characteristics of rivers, degrading spawning habitat. Dams trap sediment and promote erosion in rivers and coastal beaches. 25 From Carl, D. Introduction to Water in California. 4. 5. Challenges to the Redistribution: The Levee System *Click on the image for more on the Jones Tract levee break of 2004. 26 Challenges to the Redistribution "There are 2 kinds of levees: those that have failed and those that will fail." 1. Levee System The Central Valley has over 2,600 miles of levees. Breaches in the levee system could contaminate water supplies. Breaches in the levee system could flood great portions of the Central Valley. Over 2 billion dollars are required to repair and maintain the levee network. 27 Challenges to the Redistribution: Global Warming From Dettinger, M. Changes in Streamflow Timing in the Western United States in Recent Decades. USGS Publication. 28 Challenges to the Redistribution 1. Global Warming The California redistribution system is dependent on snowmelt. During the winter, dams protect citizens from flooding. During the summer, reservoirs supply water for irrigation and municipalities. GW has the potential to reduce snowpack and to cause snow to melt earlier. *Shasta Dam. Click on the image to learn more about the threats of global warming on California. 29 Challenges to the Redistribution 1. Population Growth California's population is expected to increase by 14 million by 2030. As a result of this population growth, water demand is expected to increase by 40% in 2030. Through conservation and the reallocation of water rights, the state should be able to meet this demand. 30 *The sprawl of Los Angeles. Click on the image to learn more about challenge of supplying water to a growing California population. CalFed to the Rescue! "You redesign the river, you restore it to a more natural functioning, and hopefully you need less water to make the system work the way it's supposed to - everybody wins." 1. CalFed originated in 1994 in an effort to balance the interests of cities, farmers, and environmentalists. 2. In this effort, billions of dollars have been allocated to CalFed from federal and state funds. 3. Specific goals: a) b) c) d) e) f) Restore 188,000 acres of wetlands and streamside habitat. Recharge underground aquifers. Streamline water transfers. Promote water use efficiency. Clean contaminated agricultural runoff. Build reservoirs and increase dam storage? 31 Is CalFed working? "I would recommend to the governor that they not spend a penny of that until somebody understands what's going on." 1. Fish and zooplankton populations in the Bay-Delta have declined since 1994. 2. CalFed has yet to significantly address water supply issues facing the state.* 1. Gov. Schwarzenegger has asked for an audit of the $3 billion spent since 2000. 1. Federal funds for the program have declined significantly since 1994. Federal appropriation for the program expired in 2000. *Read: http://www.enn.com/today.html?id=8640 32 Thought Experiment A clear-cut drought solution? In 2002, Colorado governor Bill Owens suggested that mountain forests be removed to prevent wildfires and to increase water yield. What kind of information do we need to fully evaluate his proposal? 33 34 The State Water Plan (SWP) goes for energy intensive solutions! From Bob Wilkinson`s presentation ...
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05_WaterSupplies - Water Supplies and Global Change - ESM...

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