Flood Forecasting and Warning Vienna Flood Model Presentation to Town of Tillsonburg July 13, 2009 Heather Surette Manager of Watershed Services

Nanticoke Creek on Thompson Road February 12, 2009 Overview Background Role of Conservation Authority Vienna Flood Model History Approach Application Next Steps Summary Nanticoke Creek on Thompson Road February 12, 2009

History of Flooding October 1954 Hurricane Hazel passed into southern Ontario. 81 people died Damages estimated at $25 M ($180 M current dollars)

Flooding Contributing factors (e.g. ice jams, rainfall) Major cause spring snowmelt ‘Flood plains’ or ‘flood hazard lands’ Flood plains managed to protect residents Occupied floodplains = risky business Vienna February 13, 2009

Flood Management Prevention (e.g. land use policies) Protection (e.g. dams, dykes) Emergency Preparedness and Response Emergency response plans Mitigation strategies Specific hazard identification and response (e.g. floods) Vienna February 12, 2009

Role of Conservation Authorities (CAs) Ontario Ministry of Natural Resources (MNR) and CAs are responsible for forecasting where and when flooding is likely to occur and issuing flood warnings. Monitor watershed conditions including snow conditions, precipitation and flows to aid in forecasting and warning. Advance warning of an impending flood allows municipalities to put emergency response plans into operation, and notifies the public of developing or ongoing unsafe river and lake conditions and allows individuals to take precautions. The purpose of the system is to minimize flood damage and loss of life.

Role of CA’s Conservation Authorities generally issue three different types of flood warnings: High Water Safety Bulletin Flood Advisory Flood Warning Sandusk Creek February 12, 2009

Flooding in LPRCA’s Watershed Municipality of Bayham Winter/Spring 2008 Winter/Spring 2009 significant flooding No fatalities Minor damage Big Otter Creek near Port Burwell

Village of Vienna Located in Big Otter Creek watershed Flooding in 2008/09 Infrastructure Sanitary sewers Roads Bridges Residences and business in flood plain

Vienna Flood Model History LPRCA and Bayham partnership LPRCA Comprehensive Study Impact analysis Detailed mapping Effectiveness monitoring

Vienna Flood Model Approach Computer model to determine water levels Simulation of flows and ice jams Statistical data analysis Army Corps of Engineers model

Vienna Flood Model Application Stages of flooding Identification of vulnerable infrastructure Mapping Model application Model accuracy analysis Marking of bridges Information distributed to residents Development of partnerships

Flood Stages Mapped

Vienna Flood Model Next Steps Defined agency roles and responsibilities Communication plan to improve interagency consultations Model upper reaches of Big Otter Creek Ongoing refinement Ice Jam Port Burwell February 12, 2009

Flooding at Bailey Bridge Summary Improved communications between agencies Emergency response mitigation strategies Enhanced emergency management programs Enhanced profile of LPRCA-Municipal partnership Reduces potential for negative environmental impact Flooding at Bailey Bridge