Community Flood Planning
Total Page:16
File Type:pdf, Size:1020Kb
Community Flood Planning: An assessment of hazard and response in the Dawson City region, Yukon, Canada Supervised Research Project In partial fulfillment of the Masters of Urban Planning Degree Submitted by: Erica Beasley Supervised by: Professor David Brown School of Urban Planning McGill University, Montréal October 6th, 2010 Abstract: The Dawson City region has a long history of flooding that extends beyond its establishment during the Klondike Gold Rush. Dawson has evolved into a modern settlement with infrastructure that is vulnerable to inundation. After a devastating flood in 1979, a dyke was built to protect the townsite which has helped to ameliorate the flood-threat; however, residual risks exist and development that has occurred on the Klondike River floodplain has placed newer subdivisions in peril. In this report, the structural and policy approaches implemented in the region are assessed. Information on hazards associated with climate change are synthesised and GIS is used as a tool for flood-simulation. Research findings point to deficiencies in local hazard information and the inefficiencies in land use that contribute to the encroachment of vulnerable lands. Recommendations are made for risk-minimisation, which hinge on strategic residential growth and the redistribution of essential services. Key words: Dawson City, Yukon River, Klondike River, flood, hazard, climate change, GIS, simulation Acknowledgements: This research effort was made possible thanks to the knowing and patient supervision of Professor David Brown at McGill University, and to the enduring mentoring of Professor Frank Duerden at Ryerson University. Many thanks are extended to Ryan Hennessey (Northern Climate Exchange), Bill Kendrick (Tr’ondëk Hwëch’in First Nation), Ian Robertson (Inukshuk Planning) and Jim Regimbal (Dawson Fire Department) who shared their professional wisdom of the Dawson region with me. Special thanks also go out to Sarah and John Lenart (Rock Creek residents) who spoke to me of their encounter with flooding and provided the pictures that animate their story. The field work portion of this project would not have been a reality without the generous funding provided by the International Polar Year – for the opportunity to experience Dawson City, I am truly appreciative. Table of Contents: Chapter 1: Introduction.................................................................................. 1 Dawson study area............................................................................................................................. 2 Adaptation planning for climate change............................................................................................. 2 Research objectives and report structure............................................................................................. 3 Chapter 2: Literature Review........................................................................... 5 Floodplain management in Canada: from a structural to non-structural approach............................. 5 Disaster Financial Assistance Arrangements (DFAA).......................................................................... 6 The “eco-system” approach to sustainable floodplain management..................................................... 7 Defining risk, uncertainty and vulnerability........................................................................................ 8 Integrated flood-risk management...................................................................................................... 9 Structural response to flood.............................................................................................................. 10 a) Community-wide............................................................................................................... 10 b) Individual buildings........................................................................................................... 11 Non-structural responses to flood..................................................................................................... 12 GIS as a tool for flood-risk assessment.............................................................................................. 13 Community-level flood studies: perceptions of risk........................................................................... 14 Summary.......................................................................................................................................... 16 Chapter 3: Methodology............................................................................... 17 Phase 1: Background synthesis.......................................................................................................... 17 Phase 2: Production of cartographic tools for analysis....................................................................... 17 Phase 3: Field work........................................................................................................................... 18 Phase 4: Analysis and recommendation formulation......................................................................... 18 Chapter 4: Overview of Flooding in the Yukon River Basin........................... 19 Biophysical setting of the Dawson study area.................................................................................... 20 Flooding in Yukon communities...................................................................................................... 21 Flooding in the Dawson study area.................................................................................................. 22 Climate change and hydrological response....................................................................................... 23 Predicting future hydrological regimes through paleoflood study..................................................... 27 Monitoring and emergency response in flood-affected communities................................................ 28 Chapter 5: Overview of the Dawson Study Area............................................ 29 Historical context............................................................................................................................. 29 Modern Dawson: life after the gold rush.......................................................................................... 30 Regional land use and morphology.................................................................................................. 31 a) Dawson townsite............................................................................................................... 31 b) Klondike Valley subdivisions............................................................................................. 33 c) Other subdivisions............................................................................................................. 34 Experiences with flooding and structural response............................................................................ 34 a) Dawson townsite................................................................................................................ 35 b) Klondike Valley.................................................................................................................. 37 Non-structural responses to flooding................................................................................................ 39 a) Policy-based flood management......................................................................................... 39 b) Disaster assistance.............................................................................................................. 40 c) Formal emergency response............................................................................................... 40 Chapter 6: Dawson City Flood Simulation.................................................... 42 Residual risk..................................................................................................................................... 42 Flood scenarios and GIS simulation................................................................................................. 42 Impacts to critical facilities............................................................................................................... 43 Data limitations............................................................................................................................... 45 Chapter 7: Discussion and Recommendation................................................ 50 Informational deficiencies................................................................................................................. 50 Improving communication of flood hazard information................................................................... 51 OCP re-visioning for long-term sustainability................................................................................... 52 Growth strategies for residential development................................................................................... 53 Zoning for the reduced vulnerability of critical infrastructure........................................................... 54 Enhancing household capacity to deal with flooding......................................................................... 55 Summary of recommendations......................................................................................................... 55 References.....................................................................................................