Arbitrary Flood Hazard Zones: Dialing-in the 100-yr Paradigm

点击翻译按钮获取中文摘要

For half a century, the 100-year flood hazard zone (FHZ) has been enshrined in culture and law as a planningtool to limit the growth of flood risk. This FHZ can be seen as a flood risk reduction tool with two maincomponents: 1) spatial extents; and 2) flood rules. While flood rules vary (flood proofing requirements, userestrictions, insurance regulations, and so on), many jurisdictions in the US and Canada use a single floodprobability to map the spatial extents. Generally, a 1% probability or 100-yr return period has been selected forthis as a compromise between revenue generating land-uses and flood exposure. We seek to explore the effectof this arbitrary return period, and ask: how does the 100-yr FHZ affect flood risk?To answer this question, we will compare the expected lifetime flood damage of different FHZ floodprobabilities. First, we will simulate stochastic flooding on an evolving city-scape in reaction to flood proofingrequirements for reconstructions within the FHZ. Then, assuming flood rules tied to a redefined FHZ wouldonly apply to reconstruction, we will focus on temporal and spatial dynamics of reconstruction decisions, theaccompanying reduction in vulnerability, and the scaled-up effect of these actions on the total expected flooddamage in monetary terms for a city.This proposed study leverages the flood risk assessments conducted by IBI Group for the City of Calgaryfollowing the 2013 Southern Alberta Floods, which informed decisions by projecting the existing risk forward.In partnership with IBI, the proposed study will take the next step: investigating how flood risk may changeover time in a dynamic city and how this can be minimized. This novel application of agent-based modellingwill provide an additional tool for decision makers to navigate the uncertainty of flood risk in a dynamic city.