Search results

The effects of climate change are increasingly considered in conjunction with changes in water demand and reservoir sedimentation in forecasts of water supply vulnerability. Here, the relative effects of these factors are evaluated for the Washington, DC metropolitan area water supply for the near (2010-2039), intermediate (2040-2069), and distant (2070-2099) future by repeated water resources model simulations. This system poses water management challenges because of long water-delivery travel times that increase uncertainty, multiple water jurisdictions that constrain potential decisions, and future scenarios that simultaneously increase demand and decrease water supply during the critical summer period. Adaptation strategies were developed for the system using a multiobjective evolutionary algorithm. Optimized reservoir management policies were compared using six distinct objectives ranging from reservoir storage to environmental and recreational benefits. Simulations of future conditions show water stress increasing with time. Reservoir sedimentation is projected to more than double (114% increase) the severity of reservoir storage failures by 2040. Increases in water demand and climate change are projected to further stress the system, causing longer periods of low flow and a loss of recreational reservoir storage. The adoption of optimized rules mitigates some of these effects, most notably returning simulations of 2070-2099 climate to near historical levels. Modifying the balance between upstream and downstream reservoirs improved storage penalties by 20.7% and flowby penalties by 50%. Changing triggers for shifting load to off-line reservoirs improved flowby (8.3%) and environmental (4.1%) penalties slightly, whereas changing demand restriction triggers provided only moderate improvements, but with few adverse effects. (C) 2017 American Society of Civil Engineers. ; Institute for Critical Technology and Applied Science (ICTAS) at Virginia Tech; Interstate Commission on the Potomac River Basin (ICPRB) and Hydrologics, Inc. ; This study was conducted while James Stagge was a Via Doctoral Fellow in the Department of Civil and Environmental Engineering at Virginia Tech. He gratefully acknowledges support from the Via program and the Institute for Critical Technology and Applied Science (ICTAS) at Virginia Tech. The authors would also like to thank the Interstate Commission on the Potomac River Basin (ICPRB) and Hydrologics, Inc. for providing data access and research support. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. The authors would like to thank two anonymous reviewers for their constructive comments regarding this paper. ; Public domain authored by a U.S. government employee

Forecasted changes to climate were used to model variations in the streamflow characteristics of a northern Virginia catchment. Two emission scenarios were applied from international climate projections along with four general circulation models (GCMs) by using two statistical downscaling methods to drive the hydrological simulations in two future time periods (2046-2065 and 2081-2100). Incorporation of these factors yielded 32 runoff simulation models for a 130-km(2) watershed located in northern Virginia. These models were compared with historical streamflow data from the late 20th century. Changes in streamflow were compared using median, low, and high flows. Results showed a general increase in median flows in both the mid- and late 21st century. Low flows were projected to decrease, whereas high flows were projected to increase, creating a larger range between low flows and high flows. In addition, statistical tests were conducted to identify the main factors that affected variations in future climate projections. The choice of the downscaling method emerged as the main source of uncertainty. This research quantifies the impacts of climate change as well as uncertainties within climate change projections for regional water resources. Considering the essential role of this watershed for water supply in northern Virginia, the findings of this study illustrate likely impacts of climate change on water supply reliability, supporting climate resiliency in the study area. (C) 2019 American Society of Civil Engineers. ; Australian Water Quality Centre (SAWater); Occoquan Watershed Monitoring Laboratory (OWML) ; The authors gratefully acknowledge the financial support provided by Australian Water Quality Centre (SAWater) and Occoquan Watershed Monitoring Laboratory (OWML) for this study. The views expressed in the paper are those of the authors and not necessarily of the funding bodies. The US Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, DC, 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. ; Public domain authored by a U.S. government employee

Fresh water demand is rising due to factors such as population growth, economic development, and land use changes. At the same time, climate change is rendering the water supply even more uncertain for the future. Due to recurring water restrictions and increasing water-related fees triggered by droughts and water shortages, there is a widespread, growing discomfort with respect to future water availability. Among key stakeholders and local policy makers, this has led to an increased interest in modeling the availability of water resources, with the aim of developing and implementing the appropriate water resource infrastructure and management strategies. This paper examines the Washington metropolitan area (WMA) water supply system and uses a system dynamics approach as a planning tool to make an exploratory assessment of the adequacy of the study area's water supply system to meet future water demand under the influence of substantial droughts and climate change. This assessment finds that the study area is self-sufficient under normal climate conditions during the entire planning horizon but that it will be strained under moderately severe droughts. On the basis of the temperature, streamflow and precipitation projections made by climate change models specific to the WMA region, climate change is expected to improve the water supply reliability. However, climate change has uncertainty associated with it. One of the four climate models for the Potomac River basin projects a decrease in the precipitation and streamflow, which may result in a reduction in the water supply and the system's reliability. Regulating the price and the system losses are valuable tools that can be leveraged. But these policy interventions require stakeholder participation (price regulation) and capital investments (reduction of distribution losses). Finally, system reliability can also be improved by increasing water supplies. ; Public domain authored by a U.S. government employee