1. Modeling coastal flooding in urbanized lowlands: a multi- dimensional high-resolution approach Brett F. Sanders, Professor Timu Gallien, Ph.D. Student Civil and Environmental Engineering University of California, Irvine UC Center for Hydrologic Modeling http://sanders.eng.uci.edu bsanders@uci.edu

2. Sanders Lab, UC Irvine Motivation –Coastal flooding from extreme high tides and waves / sea level rise –Inland flooding from intensified precipitation/levee failure –Emergency Management –Zoning –Infrastructure Assessment and Planning Technology Integration –Improved coverage and resolution of geospatial data –High performance computing –Advanced numerical methods Predictive models for flood risk management –Physically representative parameters –High resolution (< 10 m ) –Timely Developing knowledge base and tools for accurate mapping of flood impacts in topographically complex regions Aerial LiDAR Spatial Resources Flood Simulation, Houston, TX Baldwin Hills Flood DWR

3. Newport Harbor, CA Study Flooding from high tides and waves –Highest tides in winter and summer –Non-tidal anomalies of ~0.3 m can exacerbate flooding (El Niño storms) –Wave effects magnified at high tide Factors affecting flood map accuracy –Tidal amplification –Inventory of flow paths –Vertical accuracy of overtopping thresholds –Wave setup / wave overtopping flows –Erosion of flow barriers –Routing (hydraulic versus static) Findings to date –Static models overestimate flood extent –LiDAR insufficient for overtopping thresholds LiDAR vertical accuracy (~15 cm) RTK survey vertical accuracy (~3 cm) –Flood extent sensitive to tide height 4.4 cm tide height bias causes 250% increase in flood extent Static January 10, 2005 (Gallien et al., in prep.)

4. San Francisco Bay, CA NOAA Tsunami Inundation DEM (30 m) Spatially variable grid resolution Emphasis on topographic features (levees) near mean sea level SF Bay 2100 South SF Bay 2050 South SF Bay 2100 Simulations 2050: 16 inches SLR 2100: 55 inches SLR Tide: 12 hr period; Great Diurnal Range for SF Computing: ~1 hr on 64 processors

5. Acknowledgements We thank the National Science Foundation (CMMI-Resilient and Sustainable Infrastructure Program) and the UC Water Resources Center for grants that supported this work And we thank the City of Newport Beach and Los Angeles County for their gracious cooperation http://sanders.eng.uci.edu

6. Newport Harbor, CA Results