David Purkey

Senior Scientist


Davis, CA
dpurkey@sei-us.org
skype: dpurkey
+1 (530) 753-3035 x1#

David Purkey runs the Northern California office of SEI-US and is actively involved in the SEI Water and Sanitation Program in the the United States and globally. Much of his work centers around the development, dissemination and application of SEI's Water Evaluation and Planning (WEAP) system. His research interests include understanding the potential impacts of and adaptation to climate change in the water sector and aquatic ecosystems, integrated water resources management that focuses on linking the management of surface water and groundwater to meet a broad spectrum of objectives, and equitable management of transboundary water resources. David and his team are experienced in applying a range of hydrologic, hydraulic, and planning models in setting as diversion as California, the US-Mexico border, the Great Lakes, and West and Southern Africa. David received his Ph.D. in hydrology from the University of California, Davis in 1998.


Recent Publications by David Purkey

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An integrated assessment of water-energy and climate change in Sacramento, California: How strong is the nexus?

Climatic Change, online July 14, 2015

Author(s): Dale, L.L. ; Purkey, D. ; Heaps, C. ; Sieber, J. ; Karali, N.; Millstein, D.; Carnall, M.; Vicuña, S.; Borchers, N.; Bustos, E.; O'Hagan, J.; Collins, W.D.; Sohn, M.D.
Year: 2015

Research Area(s): Water Resources ; Energy Modeling ; Adaptation & Vulnerability

Description: This paper is among the first to report on the full integration of basin-scale models that include projections of the demand and supply of water and energy for residential, commercial, industrial, and agricultural sector users. The authors link two widely used regional planning models, WEAP and LEAP, to study the impact of rising climate variability on water and electricity use in Sacramento, Calif. Historical data, combined with the current energy and water system configuration, were used to assess the implications of changes in temperature and precipitation. Climate simulations suggest that electricity imports to the region would increase during hot dry spells, when regional power production is most constrained. In particular, regional imports of electricity would increase over 35% in hot dry years, assuming a 4°C increase in average temperature and a 25% decrease in average precipitation.
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Relevancia y utilidad del proceso ADR y del sistema WEAP para la formulación de Planes de ordenamiento y Planes de manejo de cuencas y ríos en Colombia (POMCAs y PORHs)

SEI and USAID discussion brief

Author(s): Purkey, D. ; Mendoza Salamanca, T.
Year: 2015

Research Area(s): Water Resources

Description: Este resumen de discusión describe cómo el marco Apoyo a Decisiones Robustas (ADR) y el Sistema de Evaluación y Planeación del Agua (Water Evaluation And Planning - WEAP) fortalecen y a la vez vinculan a los Planes de Ordenamiento y Manejo de las Cuencas (POMCA) y los Planes de Ordenamiento de los Recursos Hídricos (PORH). En la actualidad, los principales obstáculos para la Gestión Integral del Recurso Hídrico (GIRH) en Colombia son el insuficiente conocimiento del recurso en términos de oferta, demanda, calidad y riesgos, y la exigua participación y coordinación social en el proceso, todo lo cual tiene como resultado una menor capacidad de administración y toma de decisiones informadas. Con la metodología de planificación ADR y la herramienta WEAP se ha logrado construir una sólida base de datos numéricos y gráficos, y modelos de simulación de incertidumbres relativas a los impactos del cambio climático, cambios en el uso de la tierra, presiones demográficas y patrones de desarrollo económico sobre la cantidad y la calidad del agua necesaria para diferentes usos (biodiversidad, agricultura, energía y consumo humano).
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SEI Research Synthesis: The water-energy-food nexus

SEI Research Synthesis Brief, Managing Environmental Systems theme

Author(s): Davis, M. ; Huber-Lee, A. ; Purkey, D. ; Hoff, H.
Year: 2014

Research Area(s): Water Resources

Description: SEI's expertise in land, air and water systems has provided fertile ground for interdisciplinary research. Some of our most promising work in this regard has focused on the water-energy-food nexus, a topic that is deeply relevant to sustainable development planning and policy. The nexus approach, which grew out of systems analysis, recognizes that water, energy and food are closely linked, through global and local water, carbon and energy cycles. All three are also essential resources, but billions of people have limited access to them; and all three are under pressure from supply constraints and rapidly growing demand. This brief, part of a series synthesizing SEI research from 2009 to 2013, presents four key insights from our work, an overview of major projects and publications, and a look at new and ongoing work as well as future research pathways.
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Robust decision-making under uncertainty for a moorland ecosystem's water resources management under scenarios of climate variability

Presented at the American Geophysical Union Fall Meeting, 9-13 December 2013

Author(s): Flores, F. ; Forni, L. ; Escobar, M. ; Purkey, D.
Year: 2013

Research Area(s): Water Resources

Description: This study focuses on modeling the moorland ecosystem's water resources management under climate variability, and strengthening the capacities of local actors through a robust decision-making under uncertainty framework to analyze and plan water resources use in the region of Piura, Peru. The objective is to determine the reliability of the moorland ecosystem's water supply and to provide relevant hydrological information under scenarios of climate variability and other non-climate uncertainties. As a first step, a participatory workshop was carried out to identify the uncertainties that define availability of water resources, the potential strategies for adaptation to improve existing conditions, and the performance indicators by which to assess these uncertainties and strategies, using the XLRM assessment framework (eXogenous uncertainties, policy Levers, Relationships, and Measures). This study also used the WEAP (Water Evaluation And Planning system) platform to support water resources planning and decision-making under uncertainty e.g. climate change and other stresses in the system. The model includes the results of the XLRM framework and seeks to determine the importance that the moorlands have on the regional water system.
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Integrated assessment of policy interventions for promoting sustainable irrigation in semi-arid environments: A hydro-economic modeling approach

Journal of Environmental Management 128, 144-160

Author(s): Blanco-Gutierrez, I. ; Purkey, D. ; Varela-Ortega, C.
Year: 2013

Research Area(s): Water Resources

Description: This paper describes the development of a hydro-economic modeling framework that links a farm-based economic model and a semi-distributed hydrologic model, and its application to a semi-arid river basin in Spain. Sustaining irrigated agriculture to meet food production needs while maintaining aquatic ecosystems is at the heart of many policy debates, especially in arid and semi-arid areas. There is a growing interest in integrated approaches that include ecological and social aspects in water management programs. This paper describes an integrated economic-hydrologic modeling framework that captures the socio-economic and environmental effects of various policy initiatives and climate variability. It includes a risk-based economic optimization model and a hydrologic water management simulation model that have been specified for the Middle Guadiana basin, a vulnerable drought-prone agro-ecological area with highly regulated river systems in southwest Spain.
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