City of Ithaca Local Flood Hazard Analysis Cayuga Lake Watershed Network Update, November 2018 Liz Moran, EcoLogic LLC

Acknowledgements FUNDING This project is funded through a Title 11 Environmental Protection Fund grant from the New York State Department of State to the City of Ithaca. PROJECT MANAGER Michael Thorne, Superintendent of Public Works PROJECT CONSULTANTS US Geological Survey, Barton & Loguidice, NYS Water Resources Institute, EcoLogic, T.G. Miller, and Watts Engineering & Architecture

Three Questions How do rainfall and lake level affect the risk of flooding in the City? Where is the flood risk greatest? What can be done to mitigate the risk? Geography is destiny

Tools Design Storm Modeling and Inundation Maps (USGS) Project impacts of streamflow events (e.g., 2-, 10-, 50- 100- and 500-year events) under three Cayuga Lake level conditions

Tools Continuous Simulation Modeling (NYSWRI) Use long-term stream gauge records to calibrate a model relating precipitation to discharge and water surface elevation 1976, Journal of the American Statistical Association

Constructing a Useful Model Capture local knowledge (Municipal Consultations) How do the model projections match your experience? Critical infrastructure?

Solutions, Please! Watershed approach essential--become a sponge-- Physical and institutional measures City: levees, channel maintenance, green infrastructure, stormwater fees Upstream municipalities: retention, streambank stabilization

What’s Next Finalize modeling and use to test scenarios Identify critical areas Recommended actions Presentations to Board of Public Works, Common Council, Water Resources Council, TCOG and others