Events Calendar

PhD Seminar

Speaker: Dr. Timu Gallien , Chancellor’s Fellow and postdoctoral scholar at Scripps Institution of Oceanography

Talk Title: Urban Coastal Flood Prediction: Implications of modeling methodology, infrastructure and coastal management

Abstract: Globally, coastal flooding represents a significant humanitarian and socioeconomic hazard for urbanized communities. Accurate flood mapping is critical to quantifying evolving flood risk. However, flood maps are not rigorously validated to determine sensitivities and uncertainties relative to modeling methodology and infrastructure resolution. A two-dimensional Godunov type hydrodynamic model that solves a local Riemann problem to accommodate weir-like overflow is successfully applied to simulate tidal flooding. The shallow water model is then augmented with temporally variable empirical and numerical overtopping estimates to investigate wave overtopping flooding. Simulation results are compared to two unique validation datasets. Three critical issues in coastal flood prediction emerge; the effects of methodology (i.e. equilibrium vs. hydrodynamic), characterizing wave overtopping volumes and finally, resolving flood control infrastructure and mitigation measures. Hydrodynamic modeling methodologies integrating flood control infrastructure and overtopping processes significantly outperform traditional static flood mapping methods. Results show skilled flood predictions require substantially higher flood defense elevation accuracies, ~2 cm, than is currently associated with LiDAR topographic data (~15 cm). Finally, flood mitigation measures (e.g., elevating sea walls, storm drainage, beach management) have significant, and at times, unintended implications for backshore flooding.

Biography: Dr. Timu Gallien is a Chancellor’s Fellow and postdoctoral scholar at Scripps Institution of Oceanography. She holds a Ph.D. in Civil Engineering from University of California, Irvine and M.S. and B.S. degrees in Agricultural Engineering from Purdue University. Dr. Gallien’s research focuses on quantifying evolving coastal flood risk from sea level rise, storm events, and urbanization. She uses a combination of high resolution fluid-mechanics based models to comprehensively resolve both key flooding processes (e.g., tide, waves, embayment amplification, drainage) and urban flood defense structures (e.g., sea walls, anthropogenic berming). Dr. Gallien conducts extensive nearshore field observations to advance coastal process knowledge and quantitatively evaluate model performance.

Host: Katie Russo

Location: Seeley Wintersmith Mudd Memorial Hall (of Philosophy) (MHP) - 106

Audiences: Everyone Is Invited

Contact: Kaela Berry