Performance assessment of a water supply system under the impact of climate change and droughts: a case study of the Washington metropolitan area

Authors: BHATKOTI, R. - Virginia Tech; TRIANTIS, K.P. - Virginia Tech; Moglen, Glenn; SABOUNCHI, N.S. - Collaborator

Submitted to: Journal of Infrastructure Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2018
Publication Date: 7/9/2018
Citation: Bhatkoti, R., Triantis, K., Moglen, G.E., Sabounchi, N. 2018. Performance assessment of a water supply system under the impact of climate change and droughts: a case study of the Washington metropolitan area. Journal of Infrastructure Systems. https://doi.org/10.1061/(ASCE)IS.1943-555X.0000435.
DOI: https://doi.org/10.1061/(ASCE)IS.1943-555X.0000435

Interpretive Summary: The Washington metropolitan area (WMA) water supply is supported from several sources, the primary one being streamflow from the Potomac River. Infrastructure and agreements between Washington, DC, Maryland, and Virginia are in place to manage this water supply in the event of scarce resources. Although the WMA water supply is secure during normal flow conditions, the increasing frequency of drought and increasing WMA population have the potential to strain water resources in the future. This research employs a system dynamics model to examine complex forces and feedbacks that capture both the physical system and human interactions that relate to both water supply and demand in the WMA. The research outlines the considerations, data, and equations necessary to establish the planning-level framework that the systems dynamic model requires. Forecasts indicate that with increased population and changes in temperature, precipitation, and streamflow the reliability of the WMA would actually improve, but there is uncertainty in these forecasts. This research illustrates how human interactions with the system in the form of water price and/or reducing system losses and the feedbacks to such actions can influence future water supply reliability.

Technical Abstract: Fresh water demand is rising due to multiple factors such as, population growth, economic development and land use changes. At the same time, climate change is rendering 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 growing discomfort among people regarding the future water availability. This has led to an increased interest in modeling the availability of water resources among key stakeholders and local policy makers, with the aim of developing and implementing appropriate water resource infrastructure and management strategies. This paper examines the Washington Metropolitan Area (WMA) water supply system and assesses the adequacy of the study area’s water supply system to meet future water demand under the influence of substantial droughts and climate change. Our research has found that our study area is self-sufficient under normal climate conditions during the entire planning horizon but will be strained under moderately severe droughts. Based on temperature, stream flow and precipitation projections made by climate change models specific to the WMA region, climate change is expected to improve water supply reliability. However, climate change has uncertainty associated with it. Since one of the four climate models for the Potomac River basin projects a decrease in precipitation and stream flow, this may result in the reduction in water supply and the system’s reliability. Regulating price and 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.