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

半个世纪以来，百年一遇洪水危险区（FHZ）作为一种限制洪水风险增长的规划工具被载入文化和法律。该FHZ可以被看作是一个洪水风险降低工具，有两个主要组成部分：1）空间范围; 2）洪水规则。虽然洪水规则各不相同（防洪要求、使用限制、保险法规等），但美国和加拿大的许多管辖区使用单一洪水概率来绘制空间范围。一般来说，1%的概率或100年一遇的重现期已被选定为这之间的妥协创收土地利用和洪水风险。我们试图探索这种任意重现期的影响，并问：如何100年FHZ影响洪水风险？为了回答这个问题，我们将比较不同FHZ洪水概率的预期寿命洪水损失。首先，我们将模拟一个不断发展的城市景观的防洪要求FHZ内的重建反应随机洪水。然后，假设洪水规则绑定到一个重新定义的FHZ将只适用于重建，我们将专注于重建决策的时间和空间动态，随之而来的脆弱性减少，和缩放-这些行动对一个城市的预期洪水损失总额的影响。这项拟议的研究利用了IBI集团在2013年南阿尔伯塔省之后对卡尔加里市进行的洪水风险评估。洪水，通过预测现有的风险来为决策提供信息。与IBI合作，拟议的研究将采取下一步：调查洪水风险如何在动态城市中改变时间，以及如何将其最小化。这种基于代理的建模的新应用将为决策者提供一个额外的工具，以导航在一个动态的城市洪水风险的不确定性。

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.