Water Problems in USA Library Index :: Library of Reference Material
The Arid West—Where Water Is Scarce - WATER IN THE WEST—LIQUID GOLD
WATER IN THE WEST—LIQUID GOLD
The United States is a nation relatively rich in water resources. According to the U.S. Geological Survey's Estimated Water Use in the United States in 2000 (the latest data available), in the lower forty-eight states the total renewable supply of water is about 1,400 billion gallons per day. Nevertheless, while the nation as a whole is water-rich, this abundance is not spread evenly throughout the country. Some areas have more water than others, while some have a higher need than others. Those with the greatest need do not always have adequate water resources, a situation that can lead to serious problems and conflicts.
The American West is arid (characterized by desert land) and semiarid (prairie land), with limited and inconsistent supplies of water. From the Rocky Mountains, which form the Continental Divide, to the shores of California, lay the dry basins and deserts of the vast western region of the country. Some sources consider the threshold of the "Great American Desert" roughly at the hundredth meridian, where the landscape turns from green to brown. (A meridian is an imaginary line drawn from the North Pole to the South Pole and numbered according to the degrees of longitude. In this case, the hundredth meridian runs approximately from the central Dakotas through Abilene, Texas.)
Of the 1.9 billion acres of land in the lower forty-eight states, almost half are in the semiarid and arid regions, which receive less than twenty inches of precipitation per year. The small amount of rain and snow that falls is unevenly distributed. For example, Flagstaff, Arizona, receives more than twenty inches a year, but in Phoenix and Tucson, where most of Arizona's people live and most of the agriculture is located, the yearly rainfall averages barely nine inches. The reason for this is the North Pacific high pressure system. This is a huge zone of high atmospheric pressure that is the characteristic weather pattern for the Pacific Ocean off the coast of North America. The North Pacific High shoves virtually all precipitation toward the north.
No resource is as vital to the West's urban centers, agriculture, industry, recreation, scenic beauty, and environmental preservation as water. Throughout the history of the West, especially in California, battles have raged over who gets how much of the precious resource. The fundamental controversy is one of distribution, combined with conflicts between competing interests over the use of available supplies.
SOURCES OF WESTERN WATER SUPPLIES
Surface Water and Runoff
Precipitation (rain, snow, and sleet) is the main source of essentially all freshwater supplies in the West. The amount of precipitation largely controls the availability of surface water and groundwater. In the arid regions of the West, much of the available precipitation evaporates shortly after rains. Tucson, Arizona, for example, receives most of its annual rainfall from heavy thunderstorms during the hottest months of the year—between July and September—when much of the rainfall is lost through evaporation.
Runoff refers to water that is not immediately absorbed into the ground during a rain and runs off into lower-lying areas or surrounding lakes and streams. Runoff is the primary measure of a region's renewable water supply. In addition to rain, a large share of the West's runoff comes from the melting of mountain snowpacks, which are essentially huge reservoirs of frozen water that slowly release their supplies during the spring and summer. Much of western agriculture depends on this meltwater becoming available during the growing season.
FIGURE 8.1
Changes in Western snowpack, 1999–2095
SOURCE: "Figure 6-9. Projected Reductions in Western Snowpack Resulting from Potential Changes in Climate," in Climate Action Report 2002: The United States of America's Third National Communication under the United Nations Framework Convention on Climate Change, U.S. Global Change Research Program, May 2002, https://www.usgcrp.gov/usgcrp/Library/thirdnatcom/default.htm (accessed April 13, 2005)
Changes in climate can adversely affect this important water source. The U.S. Global Change Research Program (USGCRP) projected that the snowpack of the West's mountain ranges was very likely to decrease as the climate continued to warm, despite a projected increase in precipitation. (See Figure 8.1.) Their research suggested that in the coming years more precipitation would fall as rain (rather than as snow) and that snow-pack would develop later and melt earlier. As a result, peak streamflows would very likely come earlier in the spring, and summer flows would be reduced. The change in the timing of runoff from snowmelt is likely to have implications for water management, flood protection, irrigation, and planning.
Groundwater
The other source of water in the West is groundwater, or subterranean supplies. Most groundwater is found in aquifers, underground saturated zones full of water (all the spaces between soil and rocks, and the rocks themselves, contain water). These saturated zones are recharged (replenished) primarily from rainfall percolating through the soils. Water from streams, lakes, wetlands, and other water bodies may also seep into the saturated zones. In the saturated zone, water is under pressure that is higher than atmospheric pressure. When a well is dug into the saturated zone, water flows from the area of higher pressure (in the ground) to the area of lower pressure (in the hollow well), and the well fills with water to the level of the existing groundwater. If the pressure is strong enough, the water will flow freely to the surface; otherwise the water must be pumped.
The Ogallala or High Plains Aquifer is one of the world's largest. Located in the United States, it covers 156,000 square miles stretching from southern South Dakota to the Texas panhandle and is the largest single source of underground water in the United States. The Environmental Protection Agency (EPA) has designated the Ogallala Aquifer a sole source aquifer, meaning that at least 50% of the population in the area depend on it for its water supply. The Ogallala Aquifer provides water to portions of eight western states—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Like many aquifers in the West, this once plentiful source of underground water is rapidly being depleted because its water supply is being extracted by thousands of wells at a faster rate than can be replenished through annual rainfall. Falling water tables invariably signal that withdrawal of groundwater is exceeding the rate of replacement and that, eventually, the source of water could disappear.
In July 2002 concerns about excessive pumping of the Ogallala Aquifer prompted Senators Sam Brownback (Republican of Kansas) and Jeff Bingaman (Democrat of New Mexico) to introduce to Congress the Ogallala Aquifer Bill. Officially named the High Plains Aquifer Hydrogeologic Characterization, Mapping, and Modeling Act, the bill proposed establishing a program within the Department of the Interior to map and study the aquifer. The United States Geological Survey (USGS) would coordinate the program and would provide grants and technical assistance to those eight states (or local agencies and educational institutions) for projects that address groundwater issues. Reintroduced in 2003, the bill was passed by the Senate but stalled in the House of Representatives.
Because of the arid and semiarid climate found in much of the West, the natural replenishment of aquifer water is slow, and the consequences of the large-scale removal of groundwater are becoming more evident. These consequences include land subsidence; loss of springs, streams, wetlands, and their associated habitat; and degradation of water quality. Land subsidence is the sinking of the land surface, and can be caused by the slow drainage of water from the clay and silt sediments in and next to aquifers. As water levels in aquifers decline and the water is drained from the silt and clay soils, they compact, causing the land surface to drop. Uneven land subsidence can cause large cracks and holes in the ground, causing damage to roads, pipelines, buildings, canals and drainage ditches, railroads, and other structures. Significant land subsidence ranging from six to twenty-nine feet in depth has already occurred near Mendota and Lancaster, California; Las Vegas, Nevada; and Eloy and Phoenix, Arizona.
California has a vast network of underground water reserves. This groundwater resource is especially valuable when surface water is in short supply, as in a drought. In 1991 alone (during a seven-year drought), farmers withdrew a record 4.9 trillion gallons more than was put back in—an amount that could support every Californian at that time for almost three years. As long as the amount of groundwater extraction continues to increase, as is expected with the growing population, and recharge (the process by which water is added back to the reserves) remains below normal, the levels of available groundwater will continue to decline.
As water levels go down, a water supplier can deepen a well. The amount of energy, however, necessary to lift the remaining water to the surface increases, adding to the farmer's or water utility's cost of producing a crop or providing water supplies for cities. These additional energy costs are ultimately passed along to the water's users. Alternatively, a farmer may switch to a higher-value crop or let the land lie fallow (unplanted). Ultimately, if the groundwater is depleted, the well will go dry.
DESERT BOOM
Cities and towns in Arizona, Nevada, Utah, and New Mexico have experienced unprecedented growth in the recent past. The creation of new jobs and the influx of more people continue. The growth of the job market there since 1980 has exceeded that of the United States as a whole, and population increase has mirrored the job opportunities. Some new residents, drawn by the natural beauty of the West, "telecommute" to offices in faraway cities.
According to data from the U.S. Census Bureau, population growth exploded in the West between 1990 and 2000. (See Figure 8.2.) Nevada, where the population increased by 66.3% during those years, and Arizona, with an increase in population of 40%, lead the nation.
The Census Bureau projected continued significant population growth in the West through the year 2025. In its report Population Projections for States by Age, Sex, Race, and Hispanic Origin: 1995 to 2025, the Bureau projected that population in the West would increase at a rate of nearly twice the national average from 1995 through 2025. California, which contained 12% of the U.S. population in 1995, was projected to contain 15% of the population by the year 2025, adding about 17.7 million people during the thirty-year period.
In its November 23, 1998, seminar (updated May 22, 2003), the United States Global Change Research Program (USGCRP) discussed how population increases have affected use of water from the Colorado River Basin. According to the seminar, four of the top five fastest-growing states in the country are in the Colorado River Basin. In addition, populations in the northern Mexican states of Sonora and Baja are also increasing significantly at 5% per year, a rate of growth expected to continue.
The accompanying increase in water demand has been very rapid. In 1988 Nevada used less than 130,000 acre-feet of its 300,000 acre-foot Colorado River entitlement. By 1995, however, its use of the water grew to 225,000 acre-feet per year. The state is expected to use its full entitlement before 2025. Moreover, the population of Las Vegas grew by more than 26% between 1990 and 1994, and the total population of southern Nevada in 1990 (800,000) is expected to more than double by the year 2020. Populations in Arizona and in the northwestern region of Mexico are both expected to grow by 90% over the same period.
Growth has another price. Water is the ultimate source of growth and political power in the arid West. Often, water has to be brought to western cities from distant sources. Although most of the West's cities sprang up alongside rivers, their increasing needs for water long ago outstripped the local supplies. Nationwide, southwestern states are more dependent on public and private community water systems than are other states where use of individual wells is more prevalent.
Drilling a well in the desert is unlikely to produce an adequate supply of water. Hence, even the smallest communities now depend increasingly on water imported from other states. In 1990, for the first time, states in the lower Colorado River Basin (Arizona, California, and Nevada) used their full 7.5-million acre-foot allotment. The unprecedented growth of Phoenix, Arizona, and Las Vegas, Nevada, has resulted in warnings to California from those states that they will likely cut their annual allotments of water to California, perhaps by as much as 50%.
FIGURE 8.2
Percent change in resident population for the fifty states and the District of Columbia, 1990–2000
SOURCE: Adapted from "Figure 1. Percent Change in Resident Population for the 50 States, the District of Columbia, and Puerto Rico: 1990–2000," in United States Census 2000 Resident Population, U.S. Census Bureau, December 2000, https://www.census.gov/population/cen2000/map01bw.pdf (accessed April 13, 2005)
Changes Coming to California
Southern California relies on the Colorado River for 70% of its water. For years, California has been able to take more than its lawful portion of Colorado River water because the other six states dependent on the river—Arizona, Nevada, Colorado, Utah, Wyoming, and New Mexico—did not need their allotted share. However, that situation is changing as the population of the West surges, and the other states are pushing the government to curtail California's use of water. California is currently exceeding its allotment by at least one-fifth.
THE WEST'S FRAGILE ECOSYSTEM
The natural environmental systems of the West are very fragile. Because much of the West is arid or semiarid in climate, the ecosystems are in precarious balance. Alteration of the life-sustaining water supply can dramatically affect habitat and the plant and animal species that reside there. Under natural conditions, most of the surface water and groundwater recharge occurs at higher elevations, resulting in flow toward the center of the basins. Many of the discharge points are wetlands, springs, and streams fed by groundwater. These oases are water-dependent habitats in an otherwise harsh, dry environment and are necessary to the continued survival of plant and animal populations.
When groundwater is continually withdrawn, particularly in excess of replenishment, the effects spread outward from the area of withdrawal, decreasing the amount of water in the aquifer. Entire natural ecosystems can be affected. For example, in 1942 a mesquite woodland was present along the Santa Cruz River near Tucson, Arizona. It was a thriving habitat valued for its wild bird population. By 1989 the woodland was gone. Groundwater levels in the area had declined by more than 100 feet, depriving the plants of their water supply.
In another example, the Cienega de Santa Clara, the largest remaining bird habitat in the Colorado River delta, is now sustained mostly by the agricultural drainage water from the Wellton-Mohawk Irrigation District, a very saline water supply. The salinity of this supply has increased the salinity of the Colorado River water entering Mexico, resulting in a dispute over water quality. The problem is so severe that Congress enacted the Colorado River Basin Salinity Control Act of 1974 to deal with the problem. Because so much of the water's flow has been captured and used long before the river reaches the sea, the Colorado River delta continues to shrink and dry out, cutting off delivery of nutrients to the sea and reducing critical habitat for fisheries. This has had a detrimental effect not only on the environment but also on the economics and society of local communities.
Under Title II of the Colorado River Basin Salinity Control Act of 1974, the U.S. Department of Agriculture and the U.S. Department of the Interior manage the river's salinity, including salinity contributed from public lands. According to the Natural Resources Conservation Service in "Colorado River Basin Salinity Control Program" (https://www.nrcs.usda.gov/programs/salinity/), salts dissolved in the Colorado River cause more than $300 million in damages each year.
UNREASONABLE EXPECTATIONS
The American pioneers who settled the West knew how precious water was. They had to dig their own wells and haul the water. They watched crops dry up and turn to dust and cattle die from lack of this precious commodity. Today, most people in the United States take a plentiful supply of water for granted because of our many efficient water supply systems. As populations grow, however, particularly in the arid and semiarid West, where the availability of water has been an issue since the earliest settlement days, water supplies are becoming more limited and increasingly vulnerable to drought.
Estimating the Water Supply
Many people base their expectations of "normal" on their experiences when they were younger or what conditions have been like for the past few years. Because of the relatively short human life span, very few people, including water planners, are conscious of the fluctuations in climate across decades or centuries. Some scientists argue that the only real climatic constant is change and that people have invented the idea of "normal weather" for their peace of mind.
Comparison of a region's worst recorded drought (the drought of record) against expectations of water supply can provide a harsh reality check. Urban and agricultural planning would undergo dramatic changes if city, state, and regional planners, managers, and officials operated as if the drought of record would be the next drought. According to the National Drought Mitigation Center (NDMC), droughts of record typically last between three and seven years. For most of the country, the drought of record occurred between the 1930s and 1960s. While the same weather conditions could recur, the effects would almost certainly be different because water-use patterns and population concentrations have shifted substantially since then. These effects can be simulated using economic input/output computer models to determine the effects on society.x
Planning for drought has its limitations. One limitation is that there is no way of knowing if the next drought will be worse than the drought of record. Another is that our climate records do not go back more than 100 to 120 years, while some drought cycles can span several decades or centuries. Scientific research into tree rings (dendochronology) is providing information as to how limited our knowledge really is. For example, the work of Charles Stockton and David D. Meko at the University of Arizona's Laboratory of Tree-Ring Research tells a compelling story about climate history. In January 1983 they reported their findings in the Journal of Climate and Applied Meteorology. Although 1934, 1936, and 1939 were very dry years in the Great Plains, the drought of the 1930s paled in comparison to the droughts of 1860 and 1757, when dry conditions lasted more than three to ten years.
A good portion of California's water supply depends on runoff from precipitation (rain and snow) in the Sierra Nevada Mountains. Scott Stine, a geographer at California State University at Hayward, used carbon dating to study trees growing in lakes, rivers, and swamps. In June 1994 he reported in Nature evidence that for spans of more than a century at a time, the climate was so dry that there was little or no runoff from the Sierra Nevada Mountains. Stine was able to document that past dry spells lasted from 892 to 1112 (220 years) and from 1209 to 1350 (141 years). Stine also found that despite two droughts, the twentieth century was among the wettest in four thousand years.
What Records to Use?
Deciding which of the historic records to use in planning always involves some arbitrary judgments. The effects of these judgments can have far-reaching consequences. A good example is the basis for the 1922 Colorado River Compact, which determines how the river's water is allocated. In 1988 Barbara Brown of the National Center for Atmospheric Research investigated the data used by the U.S. Bureau of Reclamation to establish the allocations and reported her findings in Societal Responses to Regional Climatic Change: Forecasting by Analogy (Michael H. Glantz, editor, Boulder, CO: Westview Press, 1988). She reported that the Bureau used roughly calculated data gathered between 1899 and 1920 to arrive at an estimated average annual flow of 16.4 million acre-feet at Lee's Ferry, a point on the river. An acre-foot (43,560 cubic feet) is a unit of measure that is equivalent to the volume of water it takes to cover an acre to a depth of one foot.
Subsequent climatic record information now shows that theperiodfrom1899to1920wasanunusuallywetperiod in the Colorado Basin. Colorado River flows calculated from tree-ring records for the period reveal that they were the wettest twenty years in the past 450 years. Tree-ring records also show that the flow in the river has been as low as 4.7 million acre-feet per year. The ten-year annual average has been estimated to be 9.7 million acre-feet. Since the 1922 compact, flows in the river have been as low as 6.6 million acre-feet in 1934, with a ten-year annual average lowof12.5millionacre-feetayearfrom1931to1940.
The planners and engineers at the Bureau of Reclamation did not have the climate records and sophisticated technology available to us today. Despite our greater knowledge, drought management continues to be that of response to crisis instead of thoughtful advanced planning. Cities, states, and regions are reluctant to take actions that will anger citizens by restricting growth and access to water use and to raise taxes and increase expenditures to conserve water when the need for the water may not occur for many years. People are naturally optimistic and, even under drought conditions, frequently will not accept the fact that they are in a drought. They continue to reassure themselves that it will rain tomorrow, or that the next year will be a good year, despite the climatic data that show that droughts of record typically occur for two or more years in a row, or that new technology will find a way to solve the problem.
SPECTER OF INEVITABLE DROUGHT
Drought is a recurring and inevitable phenomenon. In arid and semiarid regions where water is particularly scarce, the effects of drought may be more immediately felt, but it happens everywhere in the world at some time, and all climates are susceptible. For example, an analysis of climate data for river basins in the United States from 1896 to 1995, based on National Oceanic and Atmospheric Administration data, shows that some part of the nation experienced an extreme or severe drought in every year in that period, and that in seventy-two of those years these conditions affected more than 10% of the United States. During that same period, the Pacific Northwest river basins experienced extreme or severe drought eighty-six times, while California river basins had these conditions fifty-three times. The Tennessee River Basin had the lowest number (thirty-one) of these drought events.
There is no such thing as "normal weather." The idea of normal or average weather is a mathematical construction used by the media to describe weather in terms of deviation from a mathematical norm. Close examination of climate records demonstrates that variation is normal in weather. Weather changes day to day, week to week, and one year to the next. Some weather patterns may last for years, with some decades being cool and wet while others are hot and dry. Drought is a naturally occurring part of the climate cycle.
The misconception that weather is normal and drought is an unusual circumstance is a very serious problem. Weather, in one form or another, is the source of all water for drinking, irrigation, power supply, industry, wildlife habitat, and other uses. When planners, managers, and citizens fail to recognize drought and its converse, flooding, as inevitable parts of the normal weather range, their plans fall short in anticipating water and societal needs.
A 2000 report from the U.S. Global Change Research Program stressed the importance of factoring in potential effects of climate variability when developing water conservation and supply strategies. The report, Climate Change Impacts on the United States, described various scenarios that would result from changes in climate in the United States. In addition, scientists and other researchers offered suggestions for water planners and managers to aid in efficient and effective water-supply strategies. Using historical climatic data, climate models, and sensitivity analyses (which ask how, and how much, the climate would have to change to cause major impacts on particular regions or sectors of the country) scientists suggested that in the coming years there will be more precipitation in the United States, with more of it coming in heavy downpours. In spite of this, however, scientists believe that some areas are likely to become drier as increased evaporation due to higher temperatures out-paces increased precipitation. They also suggested that droughts and flash floods are likely to become more frequent and more intense.
What Is Drought?
Drought can be defined simply as a deficiency of precipitation over an extended period, usually a season or more. This deficiency results in a water shortage for some group, activity, or part of the environment. Drought should be judged relative to some long-term average condition of balance between precipitation and evapotranspiration in a particular area. Drought is also related to the timing and the effectiveness of the precipitation. Timing refers to factors such as the period when drought is most likely to occur, delays in the start of the rainy season, and the occurrence of rain in relation to principal crop growth. Precipitation effectiveness refers to the duration, intensity, and frequency of rains or other precipitation events. In many regions of the United States and the world, high temperature, high winds, and low relative humidity are also associated with drought, increasing its severity. In normally arid and semiarid regions, the precipitation deficiency is over and above the more typical dry season.
The interaction between drought, a natural event, and the demand that people place on water supply affects society. Human activity often worsens the drought's impact. Changes in land use, land degradation, and the construction of dams all affect the hydrological characteristics of a water basin (the land area drained by a particular river and its tributaries). For example, changes in land use upstream may alter hydrologic characteristics such as water infiltration and runoff rates, causing more variable stream flow and a higher frequency of water shortage downstream.
Predicting Drought
Anyone can predict with absolute certainty that drought will occur because inevitably it will. It is the how, when, where, and for what duration that are difficult to predict. Drought is never the result of a single cause, but comes from the interaction, and sometimes compounding, of the effects of many causes. On the largest scale, global weather systems (teleconnections) play an important part in explaining global and regional weather patterns. These patterns occur with enough frequency and similar characteristics over a sufficient length of time to provide opportunities to strengthen our ability to predict long-range climate, particularly in the tropics. An example of these global systems is the El Niño/Southern Oscillation.
On a lesser scale, high-pressure systems inhibit cloud formation and result in lower relative humidity and less precipitation. Regions that are under the influence of high-pressure systems most of the year are generally deserts such as the Sahara and Kalahari Deserts in Africa. Most climatic regions experience high-pressure systems at some time, often depending on the season. Prolonged drought occurs when the large-scale deviations in atmospheric circulation patterns persist for months, seasons, or years. The extreme drought in 1988 that affected the United States and Canada was caused by the persistence of large-scale deviations in atmospheric circulation patterns, and is estimated to have cost the United States $40 billion.
There are too many variables for climatologists to accurately predict drought. Prediction depends on our ability to forecast two fundamental factors: precipitation and temperature. Scientists know that climate is inherently variable and that deviations in precipitation and temperature may last from several months to several decades. Other factors affecting their duration are air-sea interactions, soil moisture, topography, and the accumulated influence of dynamically unstable weather systems at the global scale. Until we can describe, interpret, and predict the interplay among all these factors, we cannot predict weather, including drought, with any real accuracy.
The USGCRP is actively working to promote understanding of climate change and the implications it has for the United States. According to the USGCRP's report Climate Change Impacts on the United States, advances in climate science are paving the way for scientists to project climate changes at the regional scale, allowing them to identify regional vulnerabilities and to assess potential regional effects. For example, the report suggested that the Earth's climate has changed in the past and that even greater climate change is very likely to occur during the twenty-first century. It also suggested that reduced summer runoff, increased winter runoff, and increased water demands are likely to compound current stresses on water supplies and flood management, particularly in the western United States. Understanding of the implications of these changes may help Americans adapt to an uncertain and continuously changing climate.
An emerging area of science that may help with drought prediction is the extraction of information from tree rings, the Arctic and Antarctic ice caps, prehistoric sites, and other naturally occurring "records." This information is being used to calculate the frequency of droughts in a region's history and to identify the normal precipitation in a given period. Using this information, climatologists may not be able to predict a drought, but they can calculate the probability of a drought occurring in a specific region under a particular group of climatic conditions.
DROUGHT MANAGEMENT: TOO LITTLE,
TOO LATE
Hydro-Illogical Cycle
The National Drought Mitigation Center has characterized drought management in the United States as the hydro-illogical cycle. The public in the West and elsewhere tends to assume that abundant water supplies are normal, when in fact occasional droughts of moderate duration and intensity are unavoidable. When rainfall is plentiful, the public is apathetic about the need to conserve water and to plan for severe drought conditions. Once drought begins, and signs such as failing crops and restrictions on water use begin to penetrate the public awareness, the public becomes uneasy.
The longer the drought continues, the more concern, until panic sets in, particularly as socioeconomic effects such as a decline in crops, loss of water-related FIGURE 8.3
EQIP (Environmental Quality Incentive Program) allocations to states, FY 2005
SOURCE: "FY-2005 EQIP Allocations to States," in FY-2005 Conservation Program Allocations to States by Program, United States Department of Agriculture, Natural Resources Conservation Services, March 2005, https://www.nrcs.usda.gov/programs/2005_allocations/index.html (accessed April 13, 2005) recreational opportunities and the income they generate, and stringent water rationing become evident. Calls go out for the federal, state, and local governments to "do something," resulting in crisis management. Response to immediate needs, conflicting government activities and initiatives (almost always at higher costs than under non-crisis circumstances), and the need to balance competing interests in an emotionally charged atmosphere is neither good public policy nor good resource management.
Some federal government efforts are underway toward assisting farmers and rangers to implement technologies and practices to conserve water and to mitigate the long-term effects of drought. The USDA's Environmental Quality Incentive Program is one such effort. (See Figure 8.3 and Table 8.1.)
California and the Drought Years
Drought plagued California from 1986 until 1993, the longest dry period in nearly one hundred years of record keeping. California was not alone in experiencing the drought. In many ways, the water conflicts and issues it experienced were similar to, although more severe than, those found in many western states. In recent years, however, the rising population and the increased demand for water for wildlife, recreation, and scenic enjoyment taxed water supplies. The seven-year drought illustrated to California and the nation its vulnerability to financial and ecological ruin and inconvenience and prompted residents to consider new technologies.
California's elaborate system of dams, reservoirs, aqueducts, and canals permits residents to ignore the fact TABLE 8.1
EQIP funding by state, FY 2005
SOURCE: "Environmental Quality Incentives Program: FY-2005 Financial and Technical Assistance Dollars to States," in FY-2005 Conservation Program Allocations to States by Program, United States Department of Agriculture, Natural Resources Conservation Services, March 2005, https://www.nrcs.usda.gov/programs/2005_allocations/index.html (accessed April 13, 2005)
State EQIP FY-2005
Total allocations
Alabama $16,285,108
Alaska $7,345,521
Arizona $22,584,523
Arkansas $23,652,812
California $62,114,391
Colorado $39,185,835
Connecticut $6,171,688
Delaware $6,532,427
Florida $24,123,030
Georgia $18,674,184
Hawaii $8,192,003
Idaho $19,174,741
Illinois $17,969,667
Indiana $12,574,260
Iowa $25,856,704
Kansas $30,447,213
Kentucky $13,288,086
Louisiana $18,048,303
Maine $9,806,574
Maryland $7,732,193
Massachusetts $4,952,573
Michigan $18,629,584
Minnesota $32,924,161
Mississippi $21,420,866
Missouri $23,379,201
Montana $31,810,709
Nebraska $32,123,093
Nevada $8,914,534
New Hampshire $5,726,909
New Jersey $4,386,375
New Mexico $29,802,972
New York $13,128,566
North Carolina $17,985,395
North Dakota $22,014,952
Ohio $15,823,019
Oklahoma $29,017,864
Oregon $21,839,220
Pennsylvania $12,828,822
Rhode Island $5,461,693
South Carolina $9,663,381
South Dakota $20,547,674
Tennessee $12,759,284
Texas $90,007,418
Utah $23,107,745
Vermont $5,739,903
Virginia $13,336,380
Washington $20,694,391
West Virginia $7,404,453
Wisconsin $20,962,647
Wyoming $17,803,201
Pacific Basin $1,771,577
Puerto Rico $6,150,928
Total $991,878,752
that they live in a naturally semiarid climate. California is located in a climatic high-pressure zone that hovers off its coast, causing rainfall to be diverted northward. The state normally receives less than half (44%) as much precipitation as does the southeastern portion of the United States, the nation's wettest region. The rain that does fall in California is not evenly distributed; two-thirds of the state receives fewer than twenty inches of rain a year, and significant swings in annual rainfall occur regularly. Although Northern California provides two-thirds of the state's water supply, two-thirds of the state's population lives in Southern California, which has little water of its own.
California's early settlers knew about the state's lack of natural water supplies and warned about it. Nonetheless, the rugged individualists who migrated to California developed a powerful myth about their state—that in this potential Eden, everything was possible. California's development of its most precious resource, water, has been a major factor in making the myth a reality.
Throughout the preceding century, Californians had worked to develop a state of unparalleled abundance. More than 350 canals were dug to convert the arid soil into lush fields and orchards, and 1,200 dams and reservoirs helped to alter the state's natural cycles from drought to flood and back again. The attitude that has typified the history of modern California is a confidence in the human ability to conquer the forces of nature and a contempt for the dry environment from which their state, despite the odds, has flourished. For a century, Californians have managed to fulfill their water-dependent images of what their state should be: an agricultural empire, an industrial giant, and a green paradise for the thirty-six million people who lived there as of 2004.
California's agricultural survival, and that of the other Western states, has been possible only because of extensive irrigation. Although only approximately 15% of the country's harvested acres are irrigated, most of the irrigation takes place in those states that are west of the Mississippi (except Florida), particularly in the Southwest. In California, Nevada, Arizona, and New Mexico, 75% to 100% of the acreage is irrigated. As a result, much of that acreage is affected by the pollutants and salinity that accompany irrigation. For example, approximately 94% of California's estuaries have been affected by agricultural practices, including irrigation.
THE PENDULUM SWINGS.
Public attitude is changing about what constitutes the best use of water. State, local, and federal officials say the tug-of-war is a reminder of the political complexity of water, an issue that historically pitted farmers and cities against conservationists, but in which farmers now stand largely alone. And farmers concede their power is eroding. Although some crops still thrive, watered by sprinklers with snowmelt from the mountains, thousands of acres that once produced crops have reverted to sagebrush and tumbleweed. As Californians have concentrated in cities, they have come to care more about urban issues. While urban interests once joined with farmers to build more dams, urban dwellers now usually align with conservationists.
Attitudes are also changing about the "right" to water-extravagant lifestyles in an arid climate. Northern Californians are increasingly resentful of what they see as water waste in Southern California, a land of swimming pools, golf courses, and car washes. Southern Californians answer that they live in an area of perpetual drought and have invested hundreds of millions of dollars over the years to ensure their water supplies; they deserve to use them as they see fit.
Reality of Drought
A drought occurs when the water supply is reduced to a level that cannot support existing demands. A recent California drought lasted more than seven years, the fiercest drought since the Dust Bowl in the 1930s, when California had only seven million people. Beginning in 1986, water supplies dwindled to a point where reservoir storage was only 54% of normal. Thirty-nine of the state's fifty-eight counties rationed water, and many asked the governor to proclaim a state of emergency. In 1990 the State Water Project was forced to reduce water deliveries to agricultural customers by 50%. The severity of the continuing drought was worsened by the steadily increasing demands created by industrial growth and a population increase of nearly 750,000 additional people per year.
In the San Joaquin Valley, an area the size of Connecticut, the earth dropped more than a foot, damaging roads and buildings. Water resource authorities suspended the agricultural deliveries of water. More than 2.1 million acres of crops such as grapevines and fruit trees failed due to insufficient water. Farmers who planted thirsty crops such as cotton, alfalfa, and rice were the hardest hit. Grocery shoppers in every part of the country paid higher prices for some fruits and vegetables since California is the nation's largest agricultural producer, growing more than 50% of the nation's fresh produce.
Throughout the drought, many cities and towns in California instituted severe penalties for excessive water use. Rationing, cutbacks, and conservation were required. The average mandatory reduction was 50%. The first steps by urban residents to save water were to buy low-flow showerheads, install ultralow-volume toilets, avoid washing cars, stop filling swimming pools (every fifteenth home in California has a swimming pool) and hot tubs, use dishwashers less frequently, and let lawns become brown. City dwellers were then forced to adopt more severe measures to save their meager allotments of water.
Water was categorized either as "clear" (direct from the tap), "gray" (recycled water from showers, bathtubs, sinks, and washing machines), or "black" (toilet waste-water). The "gray" water was reused to water vegetable gardens or plants. Some Californians switched to paper plates to avoid using dishwashers. Others never allowed the tap water to run while brushing their teeth or did not wait for hot water when taking showers. As water rationing became increasingly serious, code enforcers watched for violators and issued citations with fines.
The area's wildlife may require years to recover from the effects of the drought. The drought years also had a significant impact on trees. Insects, which can survive adverse conditions more easily than many other forms of life, killed enough trees to equal twelve billion board feet of lumber. Because of the dryness, fire officials continually battled forest fires. In 1990 wildfires forced the closing of Yosemite National Park for the first time in history. Many expensive homes burned to the ground as wildfires roared down the canyons. With water from rivers and reservoirs severely limited, helicopters were fitted with large buckets to allow them to scoop water from swimming pools, if necessary. These events could be repeated during any extended period without rainfall.
WATER POLICIES—STATES LEAD THE WAY
Water shortfalls are first and foremost a local and regional problem. Because of the lack of a cohesive federal water policy, states have become important innovators in devising ways to reduce long-term vulnerability to drought. In 1976–77, during the widespread U.S. drought, no state had a drought plan. In 1982 only three states had them. According to the National Drought Mitigation Center (NDMC), as of December 2003, thirty-seven states had drought plans, four had plans in development, two delegated drought planning to local authorities in lieu of a state plan, and seven remained without plans.
Most, but not all, of the more drought-prone states are committed to drought planning, as are many states in the East. The drought occurrence since 1996 has led to a rapid increase in drought planning in the southwest, south-central, and southeast states. The 2001 report of the National Drought Policy Commission to Congress emphasized the need for drought planning at the local, state, tribal, and federal levels of government.
Most state plans do not meet all the goals of the NDMC recommended planning process. Most of the plans address the response component of drought planning, defining the basic linkages between local, state, and federal entities for coordinated planning and response efforts.
Western Water Policy Review Act of 1992
At the recommendation of the Western Governors' Association, Congress adopted the Western Water Policy Review Act of 1992 (PL 102–575, Title XXX), which directed a comprehensive review of federal activities affecting the allocation and use of water in nineteen western states. The Western Water Policy Review Advisory Commission was appointed and chartered in 1995.
The commission released its findings and recommendations in 1997. In the arid West, providing adequate water supplies to meet future demands remained a top priority. Deep concern exists about the ramifications of the claims being advanced by Native American tribes to water resources and the impacts of those claims on existing rights in nonnative communities. Better cooperative efforts among the states, tribes, and federal agencies are needed.
In addition to the need for more supplies to meet growing water demands, the commission recognized that a need exists to overhaul existing water infrastructure (irrigation canals and ditches, water piping, and water storage devices). There is a significant challenge in addressing these needs while meeting the expanding demands to sustain in-stream flow and water quality for environmental maintenance and enhancement. Overlaying all of these challenges are legal and institutional conflicts that need to be addressed at the federal-state level, between states, and among various water users. The commission recommended the development and implementation of an integrated, coordinated federal policy for federal activities affecting the allocation and use of water in nineteen western states. The policy was to be developed with the full involvement of the affected states.
National Drought Policy Act of 1998
As a result of the devastating $6 billion drought in the West in 1996 and the recommendation of the Western Governors' Association in Status of Drought Report Recommendations (Response Working Group, March 1998) "to develop a national framework that integrates actions and responsibilities among all levels of government (federal, state, regional, local, and tribal)," Congress passed the National Drought Policy Act of 1998 (PL 105–199). The new law established a National Drought Policy Commission to make recommendations concerning the creation and development of an integrated, coordinated federal drought policy. The commission was to seek public input on recommendations for legislative and administrative actions to help prepare for and alleviate drought's adverse economic, social, health, and environmental effects.
In June 2001 the commission released Preparing for Drought in the 21st Century—Report of the National Drought Policy Commission. The commission recommended the following national policy:
National Drought policy should use the resources of the federal government to support but not supplant nor interfere with state, regional, local, tribal and personal efforts to reduce drought impacts. The guiding principles of national drought policy should be:
Favor preparedness over insurance, insurance over relief, and incentives over regulation
Set research priorities based on the potential of the research results to reduce drought impacts
Coordinate the delivery of federal services through cooperation and collaboration with non-federal entities
The policy is a marked shift from emphasis on drought relief, and encourages the adoption of a forward-looking stance to reduce the nation's vulnerability to drought impacts. The commission summarized its findings by stating that preparedness was the key to successful drought management; that information and research are needed to support and achieve preparedness; that insurance against drought impacts needs to be reevaluated and revamped to accommodate some new subscribers and eliminate some historic subscribers; and that a safety net is needed for the period of transition from relief-oriented drought programs to drought preparedness.
The commission recommended that the United States, through its federal government, take up a national drought policy with preparedness at its core. Federal resources should be dedicated to assisting nonfederal interests and the public-at-large to prepare for drought. The commission provided specific recommendations as to how this should be done and urged Congress to pass a National Drought Preparedness Act to achieve the implementation of the recommended policy.
WATER FIGHTS WATER RIGHTS
The early history of the migration of people to the American West in the latter part of the nineteenth century has been told in innumerable histories, films, and stories. Two important events in the process of settling the West led to laws for the allocation of the scarce water supplies in the extremely arid environment—the discovery of gold and silver in the western mountain regions and the widespread use of irrigation for crop production.
Miners searching for gold and silver diverted stream water into pipes. As a result, an informal code of water regulations started in the mining camps. The first person to file a claim to a gold or silver mine was allowed priority in getting water over any later claims. To remain the owner of a mining claim, the individual had to mark it off, take possession of it, and "work" the claim productively. This informal water law, conceived more than one hundred years ago, was called the "prior appropriation doctrine."
A few years later, this legal practice was adopted by farmers, whose absolute needs for water to irrigate the parched desert were similar to those of the miners. The "first in time, first in right" priority system gave the first farmers guaranteed water supplies in times of drought, which were frequent. This right to use water by both the miners and the farmers, who were the first nonnative settlers of the West, was exclusive and absolute. Where water was concerned, the early pioneers envisioned a dreamland with hundred-mile-long canals, emerald-green farms, and bustling cities. The prior appropriation and first in time, first in right practices conflict with the more traditional riparian rights (the right to use water, such as a stream or lake, that abuts one's property) used in the East. Riparian rights cannot be sold or transferred; water rights governed by the doctrine of prior appropriation can.
As the population of the West expanded and states began to write down their laws, the rules for water rights and use changed. The prior appropriation doctrine was modified. "Beneficial use" became the basis for a landowner's rights to water. Beneficial use has two components: the nature or purpose of the use and the efficient or nonwasteful use of water. State constitutions, statutes, or case law may define the beneficial uses of water. The uses may be different in each state, and the definitions of what uses are beneficial may change over time. The right to use water established under state law may be lost if the beneficial use is discontinued for a prescribed period, frequently summarized as "use it or lose it." Abandonment requires intent to permanently give up the right. Forfeiture results from the failure to use the water in the manner described in state statutes. Either requires a finding by the state resource agency that a water right has been abandoned or forfeited.
Priority determines the order of rank of the rights to use the water in a system: that is, the person first using the water for a beneficial purpose has a right superior to those who begin to use the water at a later date. Priority becomes important when the quantity of available water is insufficient to meet the needs of all those having rights to use water from a common source. Under a priority system, water shortages are not shared as they are under a riparian water rights system. Some western state statutes contain priority or preference categories of water use, under which higher-priority uses (such as domestic water supply) have first right to water in times of shortage, regardless of the priority date. There also may be constraints against changes or transfers involving these priority uses.
Water Projects
The federal government played a major role in encouraging the economic growth and settlement of the West. The Reclamation Act of 1902 (PL 57–161) began many years of federal involvement in constructing and subsidizing water projects in the West. The Reclamation Act was designed to provide subsidized water for small farmers who worked up to 320 acres. Over the years, however, farmers and corporations have used subsidized water to farm thousands of acres by entering into arrangements in which they lease (but do not own) farms.
Based on the existence of irrigated farmland guaranteed by federal subsidies, the West grew rapidly. Cities sprang up in the deserts, attracting a large array of support industries as people from the Eastern and Midwestern United States moved to the Southwest to enjoy the warm, dry climate, stark beauty, and sunshine.
Although some continue to argue that the American West is still a frontier—the total land area is sparsely populated, with an average of 29.4 people per square mile in New Mexico, Colorado, Utah, Nevada, and Arizona combined—the low average population density is deceptive. According to the Bureau of the Census (All Across the U.S.A.: Population Distribution and Composition, 2000), population growth in metropolitan areas in the West increased almost 20% between the years 1990 and 2000, while the population in nonmetropolitan areas in the West increased by almost 21%. (See Figure 8.4.)
UNANTICIPATED CONSEQUENCES OF IRRIGATION.
In much of the West, millions of acres of profitable irrigated land overlie a shallow and impermeable clay layer, the residual bottom of an ancient sea, that is sometimes only a few feet below the surface. Significant changes in the land can be caused by the interaction of irrigation water and this ancient seabed. During the irrigation season, temperatures in much of the desert fluctuate between 90 and 110 degrees, and much water is lost because of evaporation and plant transpiration. The water lost in "evapotranspiration" is relatively pure because chemicals are left behind to precipitate as salts and to accumulate in the soil. Evapotranspiration is the combined effect of evaporation of moisture from water bodies and land surfaces and the transpiration of plants.
Water retained in the soil seeps downward, carrying the salts with it, until it hits the impermeable clay layer. Because the water has nowhere to go, it rises back up into the plant root zone, increasing the salt content. The excessive salts can interfere with crop growth. Generally, high salt concentrations obstruct germination and impede the absorption of nutrients by plants and in some cases have rendered the soils unable to grow crops. The salts (dissolved solids) continue to accumulate as irrigation continues. A few thousand acres have already gone out of production because the soil is too salty; salt is actually visible on the ground.
To stop excessive buildup of the salts in the soil, extra irrigation water is required to flush out the salts, generally into surface drainage or groundwater. In locations where FIGURE 8.4
Percentage change in metropolitan and nonmetropolitan
populations, by region, 1990–2000
SOURCE: "Figure 2-1. Percentage Change in Metropolitan and Nonmetropolitan Populations by Region: 1990–2000," in Population Profile of the United States: 2000, U.S. Census Bureau, 2002, https://www.census.gov/population/popprofile/2000/profile2000.pdf (accessed April 13, 2005) these dissolved solids reach high concentrations, the artificial recharge from irrigation return flow can result in degradation of the quality of groundwater and the surface water to which the groundwater discharges. In severe cases, the increased salinity renders the water useless for irrigation or drinking and contributes to degraded aquatic habitats.
Buying and Selling Water Rights
Prior to the mid-1980s, the preferred method of getting water was to develop a new supply. As new supplies became less accessible and environmental regulations made supply development more difficult and expensive, creating mechanisms for voluntary water reallocation as a component of managing the demand for water has become more important. Water marketing and demand management promote efficiency and allow a considerable amount of flexibility in water resource management.
In 1986 Aurora, Colorado, a growing suburb of Denver, went shopping for water to meet its ever-increasing needs. For $50 million, the city bought the water rights from 300 financially strained farmers in the Arkansas River valley and thus increased Aurora's water supply by 30%. At one time, this sale of water rights by farmers was considered unthinkable, but the growing water demands by the West are now forcing such sales to increase. While demand for water for growing cities is far outpacing the available supplies, federal money to finance huge water projects has all but dried up. Realizing that water scarcity will inhibit future growth, western cities and industries are looking to the agricultural community for water.
Agriculture has traditionally claimed the lion's share of the West's water supplies, accounting for 80% to 90% of consumption in most states. If farmers or ranchers, however, can earn more money selling water to a nearby city than spraying it on their crops or watering their stock, shifting the water from farm to city is in their economic best interest. If the city is saved from damming a local river to increase supplies or depleting an aquifer, it may also benefit the environment.
The value of water rights has varied enormously. Advocates of the sale of water rights maintain that a free market will allow for more efficient distribution of a source that is often subsidized and just as often squandered. Conservative politicians favor it because it reduces the federal government's role in developing new water supplies. Liberal politicians also like it because more efficient use of water could benefit the environment by lessening the need for dams, which are often environmentally harmful. Since 1981 and continuing into the twenty-first century, western state legislatures have been slowly changing the old laws dealing with water rights to make water right transfers more flexible.
Opponents, including some of the farmers who agreed to sell, claim that the sales are draining the life from small, rural communities and can cause irreparable damage to the environment in the long run as the now waterless land is left to crack, bake, and turn into dust. The farmers and ranchers who have refused to sell their water rights are concerned about not only their own water supplies but also the surrounding weeds, dust, and barren land. Once water rights are sold, the use of the land for farming is over. Nevertheless, in hard financial times, many landowners take whatever price they can get.
Whether water marketing continues or not, agriculture water rights will probably erode over time wherever water demands exceed the water supply because the value of crops is normally far less than the value of drinking water or industrial water supply. Urban dwellers do not identify with the needs or problems of agriculture in maintaining the food supply. Worldwatch Institute, a private environmental group, estimated that a given amount of water used in industry generates more than sixty times the economic value of the same amount used to produce food. This trend, however, could have consequences in the future as a growing national and world population has increased need for food.
Water Banks
Not all water right transfers require that water be shifted permanently away from agriculture. Voluntary market transactions can reallocate water on a temporary, long-term, or permanent basis. A water bank (a clearing-house between the buyers and sellers of water), acting as a water broker and usually subsidized by the state, can be authorized to spend money to buy water from farmers or other sellers who are willing to temporarily reduce their own use. The bank then resells the water to drinking water suppliers, farmers, ranchers, and industries that need the water. California, Idaho, Montana, and Texas are among the states that operate water banks.
Water Ranching
In Arizona, where state law prohibits buying the rights to water without also buying the land, a more drastic measure for obtaining water has evolved. Growing cities such as Tucson and Phoenix have purchased 575,000 acres of farmland to be used as "water ranches." Some of the land will be farmed until the cities actually need the water, but if rapid growth continues, as is expected, all of it will eventually be removed from farming. In Pima County, where Tucson is located, irrigated agriculture is expected to disappear by the year 2020 as the city expands and continues to buy even more land for its water needs.
Water Conservation and Transfers in the West
Under the doctrines of prior appropriation and beneficial use, water that is not put to beneficial use will be appropriated by those next in line. If less water is needed due to a change in crops or more efficient water use, the holder risks losing the full amount of the original right. There is little incentive to conserve water unless that water can be used to irrigate additional acreage on the same property or be transferred to another user for a price. Most experts believed that legislation was necessary to encourage conservation and permit the transfer of water to other uses. California, Montana, Oregon, Texas, and Washington have enacted legislation to accomplish this.
California, the first state to pass such legislation (1982), allows conserved water to be sold, leased, or exchanged. Under the statute, a person who conserves water does not risk loss of water if it is not put to immediate use, since conservation is now defined as beneficial use. Oregon (1987) also protects the holder's allocation, although the statute allocates 25% of the conserved water to the state to maintain or enhance flows for fish and wildlife protection. Washington (1990), however, also provides financial assistance to encourage conservation efforts. Water transferred to the state is placed in a trust program to enhance stream flows, irrigation, or municipal water supplies.
Montana (1991) authorizes holders who conserve water to retain that water right and transfer the water to another user, with approval of the state government. To encourage water conservation, Texas (1993) allows appropriated water saved through a documented conservation plan to be sold or leased without fear that the right will be lost or amended under the use it or lose it rule. Despite the legislation, it is difficult to attribute actual water savings to these laws. The states continue to study the practices and will likely pass further legislation.
DESALINATION—A GROWING WATER
SUPPLY SOURCE
According to an online fact sheet of the American Water Works Association (https://www.awwa.org/Advocacy/pressroom/Desalination.cfm, 2005), there are more than 12,500 desalination plants operating in 120 countries. These plants convert seawater, brackish water, and wastewater to freshwater suitable for a variety of purposes. Sixty percent of desalination plants are located in the Middle East. As of 2005 Saudi Arabia had twenty-seven plants desalinating 70% of the country's drinking water. Only 12% of the world's desalination capacity is located in the Americas, with most of the plants in the Caribbean and Florida.
In the past few years, desalination has become a rapidly growing alternative to water scarcity. With population growth and the threat of drought throughout the United States—particularly in the nineteen western states and Florida—desalination, once considered too expensive, is looking more attractive. Hundreds of desalination plants of all sizes are operating throughout the United States, and more are coming online everyday.
The growth in the use of desalination was fueled by the adoption of the Reclamation Wastewater and Groundwater Study and Facilities Act of 1992 (PL 102–575, Title XVI). The Act directed the Secretary of the Interior to undertake a program to investigate and identify opportunities for water reclamation and reuse and authorized participation in five water-recycling projects. In 1996 Congress reauthorized the Act, expanding it to include another eighteen projects, eight of which are in Southern California, an area in desperate need of water. At the same time, Congress enacted the Water Desalination Act of 1996. The Act is based on the fundamental need to find additional sources of potable (drinkable) water. Its primary goal is development of more cost-effective and technologically efficient means to desalinate water.
What Is Desalination?
Desalination is the removal of dissolved minerals (including, but not limited to, salts) from seawater, brackish water, or treated wastewater. A number of technologies have been developed for desalination. In the United States, desalination research is directed by the Bureau of Reclamation, which is a branch of the Department of the Interior.
There are several desalination processes:
Reverse osmosis—filtered water is pumped at high pressure through permeable membranes, separating the salts from the water.
Distillation—water is heated and then evaporated to separate out the dissolved minerals. The most common methods of distillation are:
Multistage flash distillation, where the water is heated and the pressure lowered so that the water "flashes" into vapor that is drawn off and cooled to provide desalted water.
Multiple effect distillation, where the water passes through a number of evaporators in series with the vapor from one series being used to evaporate the water in the next series.
Vapor compression, where the water is evaporated and the vapor compressed; the heated compressed vapor is used to evaporate additional water.
Electrodialysis—electric current is applied to brackish water, causing positive and negative ions of dissolved salt to split apart.
The two most common desalination processes worldwide are multistage flash distillation and reverse osmosis. Although water of different quality, including seawater, brackish water, or impure industrial wastewater, can be desalinated, seawater and brackish water are the most common water sources.
Desalination Plants
In 1962 Buckeye, Arizona, became the first town in the United States to have all its water supplied by its own electrodialysis-desalting plant. The plant provides about 650,000 gallons of water daily at a cost of about $1 per 1,670 gallons. In 1967 Key West, Florida, opened a flash-evaporation plant and became the first city in the United States to draw its freshwater from the sea.
The Yuma desalting plant in Arizona is the second-largest reverse osmosis desalting plant in the world, producing about ninety-five mgd. The plant was built as a result of a dispute with Mexico over the salinity of drainage water from the Wellton-Mohawk Irrigation District in Arizona. The salinity of this irrigation return flow has caused marked deterioration in Colorado River water quality in Mexico. The problem was so severe that Congress enacted the Colorado River Basin Salinity Control Act to fund the plant's construction.
The saline drainage water from farmlands east of Yuma flows in a concrete drainage canal to the desalting plant. The drainage water enters the plant intake system where screens remove algae and large debris such as tree limbs. As the drainage water flows into the plant, it is treated with chlorine to kill organisms and stop the growth of algae, which would damage or plug the filters and membranes.
Before being desalted, the water passes through several pretreatment steps to remove all solids that would interfere with the membrane performance. Pretreatment extends the life of the reverse osmosis membranes three to five years. Without pretreatment, the membranes would last about one hour. It takes about 4.5 hours for a unit of water to travel through the plant, from where it enters as untreated drainage water, is pretreated and subjected to reverse osmosis, and then discharged to a small canal that empties into the Colorado River.
LIMITATIONS OF SEAWATER DESALINATION.
One major limitation of desalination projects is their cost. The cost to produce water through desalination depends on the technology used, the plant capacity, and other factors. Price estimates for water produced by desalination plants in California ranged from $1,000 to $4,000 per acre-foot. In comparison, traditional water source costs range from $27 to $269 per acre-foot. For new supplies that are developed, costs are about $600 to $700 per acre-foot. During the 1988 drought, however, Santa Barbara, California, paid $2,300 per acre-foot, while permanently tying into the California Water Project would cost about $1,300 per acre-foot. Given the cost of new supplies, the cost of desalting water becomes more competitive.
Desalination requires relatively large parcels of land, preferably near the coast. Pumping seawater and brine over long distances to avoid the need for a coastal location would add to desalination's already considerable expense. Nevertheless, the demand for water by a growing population, the effects of drought on the cost and availability of water, and the technical improvements in the desalination process have led city planners to consider the expensive alternative. As other sources of water become more expensive or less available, desalination becomes more attractive. Advocates of desalting plants claim that the price of water in the West will inevitably rise as demand outpaces supply, while the cost of desalting will fall as technology improves.
On February 12, 2003, the U.S. Bureau of Reclamation and the U.S. Department of Energy's Sandia National Laboratories announced the release of a "research road map" designed to guide future investments necessary to reduce the cost of desalination. The report, Desalination and Water Purification Technology Roadmap: A Report of the Executive Committee, also described related advanced water treatment technologies and enhanced uses of desalination.
While recognizing the high cost of desalination technologies—$1 to $3 per thousand gallons of desalinated water compared to prices as low as pennies per thousand gallons—researchers believe that by 2020 desalination and water purification technologies can contribute significantly to ensuring a safe, sustainable, affordable, and adequate water supply for the United States. In fact, the report stressed the increasing strain on water supplies in the United States and the possibility that desalination technologies will have to be used to keep up with demand.
Researchers suggested that while the desalination cost of $3 per thousand gallons of water might appear to be expensive, consumers have shown a willingness to pay the equivalent of $7,945 per thousand gallons for bottled water (based on a shelf price of $.99 per half-liter bottle).
Desalination is becoming increasingly important in this age of severe water shortages. On March 12, 2003, five major municipal water agencies in California joined together to form the U.S. Desalination Coalition. According to information on the group's Web site (www.usdesal.org), the coalition's mission is to pursue federal legislation to establish a new program to provide federal financial assistance to encourage the development of seawater desalination projects. Specifically, their goal is to develop and pass legislation to assist in funding the planning, design, construction, operation, and maintenance of projects to desalinate seawater and convey the treated water for municipal and industrial use.
WATER REUSE
Wastewater from sewage treatment plants is one of the largest potential sources of freshwater where supplies are limited. About 60% to 90% of the potable water delivered to urban residents in the United States is discharged into sewage collection systems. After it has been treated to kill pathogens and remove contaminants, it can be reused for irrigation and industrial use, and to maintain stream flow.
Indirect reuse of treated municipal wastewater is becoming increasingly attractive to many municipalities, especially in the West. The Orange County Water District in California injects treated wastewater from a sewage treatment plant into its water supply aquifer to prevent the intrusion of salt water. Throughout California, construction is already underway on a number of reclamation facilities to provide reclaimed water for irrigation, and landscape and lawn watering. When completed, the program will serve an area of more than 700 square miles, providing 50,000 acre-feet of reclaimed water annually to local water supplies. Facilities will include up to eleven new or expanded water reclamation plants, state-of-the-art water purification plants, and hundreds of miles of reclaimed water delivery pipelines.
TABLE 8.2
The five realities of water in the West
SOURCE: "The Five Realities," in Water 2025: Preventing Crises and Conflict in the West, U.S. Department of the Interior, Bureau of Reclamation, May 2003, https://www.doi.gov/water2025/index.html (accessed April 13, 2005)
Five interrelated realities of water management are creating crises in important areas in the West. These realities are:
Explosive population growth
Water shortages exist
Water shortages result in conflict
Aging water facilities limit options
Crisis management is not effective
WATER (2025)
Problems in the West, including explosive population growth, existing water shortages, conflicts over water, aging water facilities, and ineffective crisis management, have led to a U.S. Department of the Interior proposal designed to assist communities in addressing these needs. A May 2, 2003, Department of the Interior press release, Water 2025: Preventing Crises and Conflict in the West, calls for concentrating existing federal financial and technical resources in key western watersheds and in critical research and development, such as water conservation and desalinization, that will help to predict, prevent, and alleviate water supply conflicts. Table 8.2 outlines the five "realities" of water in the West as identified in Water 2025.
The proposal emphasizes the need for states, tribes, local governments, and the public to decide how best to resolve the water supply crisis in the West. As part of this plan, the Bureau of Reclamation prepared an analysis of potential water supply crises and conflicts that may occur by the year 2025. The Bureau of Reclamation intends to seek extensive input from states, tribes, and the public on the prepared analysis and will revise and improve the analysis as needed.
Water 2025 is a departure from previous plans in that its focus is on strategies and measures that can be put in place before events such as drought bring further divisiveness to communities in the West. The Bureau of Reclamation believes that conflict can be minimized or avoided when potential water supply crises are addressed in advance by local and regional communities. (See Figure 8.5.) Its water-crisis prevention efforts will focus on four key tools:
Water conservation, water-use efficiency, and markets
Collaboration
Improved technology
Removal of institutional barriers and increasing inter-agency coordination
FIGURE 8.5
Potential water supply crises by 2025
SOURCE: "Potential Water Supply Crises by 2025," in Water 2025: Preventing Crises and Conflict in the West, U.S. Department of the Interior, Bureau of Reclamation, May 2003, https://www.doi.gov/water2025/index.html (accessed April 13, 2005)
WATER CONSERVATION, WATER-USE EFFICIENCY, AND MARKETS.
The Bureau of Reclamation has identified Supervisory Control and Data Acquisition systems as one area in which water conservation efforts can be improved in the management of rivers. These systems allow river managers to remotely monitor and operate key river and canal facilities on a real-time basis. The Bureau recommends that individual stations be set to monitor river levels or flow rates continuously. This will help the Department of the Interior and water district managers to respond to daily water management needs and emergencies in a timely fashion by controlling pump and canal facilities remotely. According to the Bureau of Reclamation, although the cost of this high-tech equipment has become more affordable over time, less than 20% of irrigation water delivery systems use this technology.
Research indicates that for every dollar spent on canal modernization (such as rehabilitating canal gates), an expected return of three to five dollars in conserved water can be achieved. In addition, for every dollar spent on maintaining an existing canal lining, a return of up to $10 in conserved water can be achieved. Canal-lining technologies have reduced seepage losses in central Oregon by as much as 50%.
Additional measures recommended by the Department of the Interior's Bureau of Reclamation include improvement in design and construction of new measuring devices for irrigation water delivery systems, continued support for water banks and water markets, and interagency efforts to coordinate existing and new water conservation programs.
COLLABORATION.
The Bureau of Reclamation points to litigation over competing water rights as one of the problems affecting water supply and conservation efforts in the West. Water managers sometimes must wait years or even decades until adjudication is completed. In the meantime, they do not know how to allocate water in times of scarcity. The Department of the Interior intends to work with states, tribes, and other interested stake-holders to find ways in which to accelerate court proceedings in order to protect existing federal and nonfederal rights.
An example of successful facilitation efforts occurred in California. According to the Bureau of Reclamation, for more than two decades the East Bay Municipal Utility District and several localities struggled over the management of the Sacramento River, resulting in the disruption of the efficient use of water. Facilitation sponsored by the Bureau of Reclamation led to a sustainable and locally developed agreement among the interested parties.
IMPROVED TECHNOLOGY.
Recognizing that waste-water, salty water, and other impaired water can be purified to increase their usefulness, the Department of the Interior will facilitate research to reduce the high costs that impede adoption of new water purification technologies. The Department of the Interior recommends that the United States Geological Survey make a comprehensive study of untapped but impaired water supplies with a focus on locations with a high probability of water demands exceeding supplies by 2025.
Another recommendation by the Bureau of Reclamation is the reduction of the high costs of water desalination. The Department of the Interior intends to facilitate the implementation of desalination and advanced water treatment through improved interagency coordination of research and focused investments to areas most in need of planning support.
REMOVAL OF INSTITUTIONAL BARRIERS AND INTERAGENCY COOPERATION.
According to the Department of the Interior, in some areas of the West, federal facilities have excess capacity during certain times of the year that could be used to satisfy unmet demands elsewhere. Sometimes this excess capacity is not available because of policy or legal constraints. The Department of the Interior believes that in some cases, this additional capacity can be made available with appropriate changes in Department of the Interior policies.
The Department of the Interior will cooperate with other federal agencies to more effectively focus federal dollars on critical water shortage areas. Through active support of the National Drought Monitoring Network the Department will help accelerate the development of strategies for drought preparedness.
Additional measures include the formation of Drought Action Teams to focus scarce resources quickly when and where they are needed, and the publication by the USGS of water resources assessments online so that decision makers can better understand the water supply component of drought conditions.
Disputes over water and its use will continue to be a major issue in the West well into the twenty-first century.
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