SERDP and ESTCP have launched a webinar series to promote the transfer of innovative, cost-effective and sustainable solutions developed through projects funded in five program areas. The webinar series targets Department of Defense and Department of Energy practitioners, the regulatory community and environmental researchers with the goal of providing cutting edge and practical information that is easily accessible at no cost.

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Webinar #92 (06/20/2019)

Developing Adaptation Strategies to Address Climate Change and Uncertainty

Dr. Yonas Demissie, Washington State University

Dr. Mark Wigmosta, Pacific Northwest National Laboratory

June 20, 2019

12:00 PM ET (9:00 AM PT)

Abstracts

“Linked Rainfall and Runoff Intensity-Duration-Frequency in the Face of Climate Change and Uncertainty” by Dr. Yonas Demissie

The Department of Defense (DoD) recognizes the effects of a changing climate as a national security threat with potential impacts on its mission, installations and operations. One of the anticipated effects of climate change is the increase in intensity or frequency of extreme precipitation and subsequent flood events. Adaptation to this change requires proper design and management of stormwater facilities using improved characterization of the intensity-duration-frequency (IDF) of storms by considering their nonstationarity, the different sources of uncertainty and impacts of snow. The primary objective of this project is to revise and update the storm and flood IDF curves for the selected military installations by considering the changes in past and future storm and flood events, the effect of snowmelt, modeling and data uncertainties. Regional frequency analysis coupled with Bayesian uncertainty quantification and model averaging methods were used to update the rainfall IDF curves, which are then used in site-specific hydrologic models to develop the runoff IDF curves and to assess the vulnerability of military installations to flooding. The resulted rainfall and runoff IDF curves provide reliable, forward-looking, and spatially resolved characteristics of storm events and flooding risks for thorough review and update of the current stormwater design standards at the selected installations. An interactive web-based GIS interface was developed containing tabulated and geo-referenced IDF data and figures. This presentation will describe the project’s technical approach and demonstrate the updated IDF results and the GIS web interface.

“Enhancing Hydrologic Design through Next-Generation Intensity-Duration-Frequency Curves Considering Snowmelt and Climate Nonstationarity” by Dr. Mark Wigmosta

This project supports SERDP’s efforts to update hydrologic design to assist in the management of design risks encountered under changing climate conditions. In particular, this project developed improved understanding of, and responses to, changes in the timing and intensity of rainfall- and snowmelt-based runoff events. Observation-based precipitation intensity-duration-frequency (PREC-IDF) curves are a standard tool used to derive design floods for hydraulic infrastructure worldwide. In snow-dominated regions where a large percentage of flood events are caused by snowmelt and rain-on-snow events, precipitation alone can be a poor predictor of flood risk. We developed and successfully tested next-generation intensity-duration-frequency (NG-IDF) curves, which characterize the actual water reaching the land surface (all melt events plus rainfall on snow-free ground), as an alternative to the standard PREC-IDF curves. NG-IDF curves are available at 1/16° spatial resolution covering the Contiguous U.S. for both historical (1950–2005) and future periods (2006–2099) under the RCP8.5 scenario. GCM model structure uncertainties are also considered. Both historical and future NG-IDF curves are accessible electronically. This presentation will describe the development of NG-IDF curves and evaluate the accuracy of estimated flood frequency when they are used in standard methods of hydrologic design.

Speaker Biographies

Dr. Yonas Demissie is an Assistant Professor of Civil and Environmental Engineering at Washington State University (WSU). His current research focuses on stochastic hydrology, hydro-climatology, data mining and machine learning, watershed hydrology, and stormwater management. He served as a principal investigator on multiple research projects focused on climate change and frequency analyses of floods and droughts. He has authored several articles and book chapters on the topics. Prior to joining WSU, he was a postdoctoral research associate in the Environmental Science Division at Argonne National Laboratory. He received a bachelor’s degree in agricultural engineering from Haramaya University in Ethiopia, a master’s degree in water resources engineering and hydrology from Vrije Universiteit Brussel in Belgium, and a doctoral degree in civil engineering from the University of Illinois at Urbana-Champaign.

Dr. Mark Wigmosta is a Chief Scientist and Technical Lead for the Computational Watershed Hydrology Team at the Department of Energy’s Pacific Northwest National Laboratory. He also has a dual appointment as a Distinguished Faculty Fellow in the Department of Civil and Environmental Engineering at the University of Washington. He has 30 years of experience in distributed watershed hydrology, including the potential impacts of land-use and climate change on water resources and renewable energy. He has authored more than 55 peer-reviewed research papers and book chapters, including the 22nd most citied paper since 1965 in the American Geophysical Union Journal of Water Resources Research. He earned both a bachelor’s (1981) degree and a master’s degree (1983) in geology, and a doctoral degree (1991) in environmental engineering from the University of Washington in Seattle, Washington.

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