EMS Flood Event

Last data update: April 29, 2021 This Emergency Management System (EMS) layer contains both riverine and Lake based floodplain delineations. The storm event levels (5, 10, 25, 50, 100 year and regional) riverine floodplain delineations are based on existing hydraulic and hydrologic analysis. In general, engineered riverine floodplain is available for York Region, Municipality of Durham, and in Innisfil and Bradford-West Gwillimbury of Simcoe County. In general, estimated riverine floodplain is available for Ramara, Oro and in isolated locations within Uxbridge and Brock. The storm event levels (5 and 100 year) for Lake based floodplain, are based on existing coastal engineering analysis. The EMS flood event floodplain delineations are to be used only in support of EMS activities. These flood event delineations are not to be used for any regulatory limit discussion or development application. Please follow-up with the LSRCA Engineering Department to confirm any additional requirements to support submissions with an impacts on the floodplain. The EMS flood event floodplain delineations are a new product based on "engineered" or "estimated" modelling are calculated by following standard methodologies as outlined in provincial and federal floodplain modeling guidelines. Additional cross-sections were added to the analysis from the most recent terrain surface available, to refine delineations of event storms. All EMS flood event delineations were completed using digital Elevation Model (DEM) with an elevation accuracy of +/-0.5 m. The delineation layers have been dissolved at each discrete EMS flood event level.