Watershed

Oral

395074 - Risks associated with sea level extremes under nonstationarity arising from systematic trends and natural variability

Wednesday, June 6
2:00 PM - 3:30 PM
Location: Greenway IJ
Co-Authors: Jose Salas, Fort Collins – Colorado State University

Populated urban centers and natural areas located in low-lying coastal regions are highly vulnerable to sea level extremes. They are affected by a variety of factors such as, systematic trends and interannual variability in mean sea level, astronomical tides, prevailing wind patterns, and dynamics of ocean currents, which cause nonstationarity (in sea level extremes.) For these reasons, hydrologic designs of coastal infrastructure based on concepts of return periods and risks need to incorporate nonstationarity arising from systematic trends and natural variability. Current projections of future sea levels include systematic trends with varying degrees of acceleration in both scenario-based and probabilistic approaches. Recent advances in extensions to concepts of return period and risks provide guidance for hydrologic design under nonstationarity in systematic trends but not natural variability of external factors which may influence probability distributions of extremes. Because natural variability is basically a stochastic process, its evolution into the future cannot be predicted deterministically. Therefore, sea level extremes may be modeled as functions of covariates representing such natural variability and the concepts of return period and risks will need to incorporate the stochastic nature of future natural variability in hydrologic design of coastal infrastructure. This presentation will review the concepts of risks and nonstationarity relevant to sea level extremes and provide an approach for dealing with both systematic trends and natural variability in hydrologic designs associated with coastal infrastructure. The presentation will end with a discussion of many challenges associated with this approach.

Jayantha T B Obeysekera


South Florida Wtr Mngt Dstrct

Jayantha Obeysekera, Ph.D., P.E, D.WRE
South Florida Water Management District | Chief Modeler
Jayantha Obeysekera is the Chief Modeler at the South Florida Water Management District (SFWMD), a regional governmental agency in South Florida, United States. He served as a member of the federal advisory committee which directed the development of the most recent National Climate Assessment in 2014. He was also a co-author of the sea level rise projections report published by NOAA for the National Climate Assessment and a lead author for the Southeast Chapter of the National Climate Assessment. Dr. Obeysekera was a member of three panels of the National Research Council dealing with water resources issues of (a) Klamath River in California and Oregon; (b) California Bay Delta; and (c) Edwards Aquifer system in Texas (serving currently). He is also serving as a member of the Coastal Assessment Regional Scenario Working Group associated with the Department of Defense.
Dr. Obeysekera holds a bachelor’s degree in Civil Engineering from University of Sri Lanka, M. Eng. from University of Roorkee, India, and a Ph.D. in Civil Engineering from Colorado State University with specialization in water resources. He worked as an Assistant Professor in the Department of Civil Engineering at Colorado State University. He also has taught courses in the water resources area at George Washington University, Washington, D.C. and at Florida Atlantic University, Boca Raton. He has also held the position of Courtesy Associate Professor, Department of Civil and Environmental Engineering, University of South Florida in Tampa. Currently he serves as an Affiliate Research Professor at Florida Atlantic University.
Dr. Obeysekera is the recipient of the 2015 Norman Medal of the American Society of Civil Engineers for a technical paper that makes a definitive contribution in engineering.


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395074 - Risks associated with sea level extremes under nonstationarity arising from systematic trends and natural variability



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