Recent studies of past climate and streamflow conditions have broadened understanding of long-term water availability in the Colorado River, revealing many periods when streamflow was lower than at any time in the past 100 years of recorded flows. That information, along with two important trends—a rapid increase in urban populations in the West and significant climate warming in the region—will require that water managers prepare for possible reductions in water supplies that cannot be fully averted through traditional means. Colorado River Basin Water Management assesses existing scientific information, including temperature and streamflow records, tree-ring based reconstructions, and climate model projections, and how it relates to Colorado River water supplies and demands, water management, and drought preparedness. The book concludes that successful adjustments to new conditions will entail strong and sustained cooperation among the seven Colorado River basin states and recommends conducting a comprehensive basinwide study of urban water practices that can be used to help improve planning for future droughts and water shortages.

Concern over terrorist attacks since 2001 has directed attention to potential vulnerabilities of the nation''s water and wastewater systems. The Environmental Protection Agency (EPA), which leads federal efforts to protect the water sector, initiated a research program in 2002 to address immediate research and technical support needs. This report, conducted at EPA''s request, evaluates research progress and provides a long-term vision for EPA''s research program. The report recommends that EPA develop a strategic research plan, address gaps in expertise among EPA program managers and researchers, and improve its approaches to information dissemination. The report recommends several high-priority research topics for EPA, including conducting empirical research in behavioral science to better understand how to prepare people for water security incidents.

National interests in greater energy independence, concurrent with favorable market forces, have driven increased production of corn-based ethanol in the United States and research into the next generation of biofuels. The trend is changing the national agricultural landscape and has raised concerns about potential impacts on the nation''s water resources. To help illuminate these issues, the National Research Council held a colloquium on July 12, 2007 in Washington, DC. Water Implications of Biofuels Production in the United States, based in part on discussions at the colloquium, concludes that if projected future increases in use of corn for ethanol production do occur, the increase in harm to water quality could be considerable from the increases in fertilizer use, pesticide use, and soil erosion associated with growing crops such as corn. Water supply problems could also develop, both from the water needed to grow biofuels crops and water used at ethanol processing plants, especially in regions where water supplies are already overdrawn. The production of "cellulosic ethanol," derived from fibrous material such as wheat straw, native grasses, and forest trimmings is expected to have less water quality impact but cannot yet be produced on a commerical scale. To move toward a goal of reducing water impacts of biofuels, a policy bridge will likely be needed to encourage growth of new technologies, best agricultural practies, and the development of traditional and cellulosic crops that require less water and fertilizer and are optimized for fuel production.

Growing demands for water in many parts of the nation are fueling the search for new approaches to sustainable water management, including how best to store water. Society has historically relied on dams and reservoirs, but problems such as high evaporation rates and a lack of suitable land for dam construction are driving interest in the prospect of storing water underground. Managed underground storage should be considered a valuable tool in a water manager''s portfolio, although it poses its own unique challenges that need to be addressed through research and regulatory measures.

Desalination assesses the state of the art in relevant desalination technologies, and factors such as cost and implementation challenges. It also describes reasonable long-term goals for advancing desalination technology, posits recommendations for action and research, estimates the funding necessary to support the proposed research agenda, and identifies appropriate roles for governmental and nongovernmental entities.

Of all the outputs of forests, water may be the most important. Streamflow from forests provides two-thirds of the nation''s clean water supply. Removing forest cover accelerates the rate that precipitation becomes streamflow; therefore, in some areas, cutting trees causes a temporary increase in the volume of water flowing downstream. This effect has spurred political pressure to cut trees to increase water supply, especially in western states where population is rising. However, cutting trees for water gains is not sustainable: increases in flow rate and volume are typically short-lived, and the practice can ultimately degrade water quality and increase vulnerability to flooding. Forest hydrology, the study of how water flows through forests, can help illuminate the connections between forests and water, but it must advance if it is to deal with today''s complexities, including climate change, wildfires, and changing patterns of development and ownership. This book identifies actions that scientists, forest and water managers, and citizens can take to help sustain water resources from forests.

The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation''s rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges. This book calls for an entirely new permitting structure that would put authority and accountability for stormwater discharges at the municipal level. A number of additional actions, such as conserving natural areas, reducing hard surface cover (e.g., roads and parking lots), and retrofitting urban areas with features that hold and treat stormwater, are recommended.

Recent studies of past climate and streamflow conditions have broadened understanding of long-term water availability in the Colorado River, revealing many periods when streamflow was lower than at any time in the past 100 years of recorded flows. That information, along with two important trends—a rapid increase in urban populations in the West and significant climate warming in the region—will require that water managers prepare for possible reductions in water supplies that cannot be fully averted through traditional means. Colorado River Basin Water Management assesses existing scientific information, including temperature and streamflow records, tree-ring based reconstructions, and climate model projections, and how it relates to Colorado River water supplies and demands, water management, and drought preparedness. The book concludes that successful adjustments to new conditions will entail strong and sustained cooperation among the seven Colorado River basin states and recommends conducting a comprehensive basinwide study of urban water practices that can be used to help improve planning for future droughts and water shortages.

Concern over terrorist attacks since 2001 has directed attention to potential vulnerabilities of the nation''s water and wastewater systems. The Environmental Protection Agency (EPA), which leads federal efforts to protect the water sector, initiated a research program in 2002 to address immediate research and technical support needs. This report, conducted at EPA''s request, evaluates research progress and provides a long-term vision for EPA''s research program. The report recommends that EPA develop a strategic research plan, address gaps in expertise among EPA program managers and researchers, and improve its approaches to information dissemination. The report recommends several high-priority research topics for EPA, including conducting empirical research in behavioral science to better understand how to prepare people for water security incidents.

National interests in greater energy independence, concurrent with favorable market forces, have driven increased production of corn-based ethanol in the United States and research into the next generation of biofuels. The trend is changing the national agricultural landscape and has raised concerns about potential impacts on the nation''s water resources. To help illuminate these issues, the National Research Council held a colloquium on July 12, 2007 in Washington, DC. Water Implications of Biofuels Production in the United States, based in part on discussions at the colloquium, concludes that if projected future increases in use of corn for ethanol production do occur, the increase in harm to water quality could be considerable from the increases in fertilizer use, pesticide use, and soil erosion associated with growing crops such as corn. Water supply problems could also develop, both from the water needed to grow biofuels crops and water used at ethanol processing plants, especially in regions where water supplies are already overdrawn. The production of "cellulosic ethanol," derived from fibrous material such as wheat straw, native grasses, and forest trimmings is expected to have less water quality impact but cannot yet be produced on a commerical scale. To move toward a goal of reducing water impacts of biofuels, a policy bridge will likely be needed to encourage growth of new technologies, best agricultural practies, and the development of traditional and cellulosic crops that require less water and fertilizer and are optimized for fuel production.

Growing demands for water in many parts of the nation are fueling the search for new approaches to sustainable water management, including how best to store water. Society has historically relied on dams and reservoirs, but problems such as high evaporation rates and a lack of suitable land for dam construction are driving interest in the prospect of storing water underground. Managed underground storage should be considered a valuable tool in a water manager''s portfolio, although it poses its own unique challenges that need to be addressed through research and regulatory measures.

Desalination assesses the state of the art in relevant desalination technologies, and factors such as cost and implementation challenges. It also describes reasonable long-term goals for advancing desalination technology, posits recommendations for action and research, estimates the funding necessary to support the proposed research agenda, and identifies appropriate roles for governmental and nongovernmental entities.

Of all the outputs of forests, water may be the most important. Streamflow from forests provides two-thirds of the nation''s clean water supply. Removing forest cover accelerates the rate that precipitation becomes streamflow; therefore, in some areas, cutting trees causes a temporary increase in the volume of water flowing downstream. This effect has spurred political pressure to cut trees to increase water supply, especially in western states where population is rising. However, cutting trees for water gains is not sustainable: increases in flow rate and volume are typically short-lived, and the practice can ultimately degrade water quality and increase vulnerability to flooding. Forest hydrology, the study of how water flows through forests, can help illuminate the connections between forests and water, but it must advance if it is to deal with today''s complexities, including climate change, wildfires, and changing patterns of development and ownership. This book identifies actions that scientists, forest and water managers, and citizens can take to help sustain water resources from forests.

The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation''s rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges. This book calls for an entirely new permitting structure that would put authority and accountability for stormwater discharges at the municipal level. A number of additional actions, such as conserving natural areas, reducing hard surface cover (e.g., roads and parking lots), and retrofitting urban areas with features that hold and treat stormwater, are recommended.