Development and Application of a Coastal Community Flood Resilience Planning Toolkit

Abstract

Resilience of communities against natural hazards has always been a concern of planners and engineers, but the 21st century has seen a sharp increase in the exposure of our built environment to increasing frequency and intensity of these events. Flooding has grown to be of particular importance given the wide breadth of citizens who live within proximity to coastlines, rivers and are exposed to more intense rainfall with an ever-widening lens of those in direct danger of this hazard. In fact, the US Senate estimates that flooding generates between $179.8 to $496.0 billion in direct and indirect damages annually (Jec 2024). However, planners and engineers have struggled to adapt the traditional transportation planning process to include measures related to resilience against these flood events due to a lack of proper assessment tools. This has led them to create their own methodology for evaluating their community’s vulnerability and where to prioritize investments for future mitigation practices. This document aims to describe a flooding resilience evaluation toolkit developed to address this apparent gap between academic knowledge and practical application so that communities can begin to incorporate flood resilience into their planning process. This toolkit will consist of an excel-based GIS attribute table calculator program and an online vulnerability assessment map that will be (a) centered around quantifiable performance measures, (b) utilize readily available data sources, (c) be scalable across different geographies and regions, (d) provide visual and/or analytical insights into resilience impacts, and (e) be validated and assessed. The results of this effort show that the toolkit can accurately utilize existing flood prediction models and census records to identify areas of concern for planners and engineers to better prioritize project development. This is accomplished with nine, literature-based performance measures to compliment existing databases and build on the knowledge of infrastructural, economic and social resilience evaluations. These performance measures were incorporated into both an excel-based and online tool that can work in tandem to form the full toolkit. The application of this toolkit in a case-study evaluation of Mobile Bay found that the online portion is ideal of initial assessment of current conditions, while the excel-based tool is meant for subsequent, in-depth analysis and possible impact changes from future mitigation practices. Furthermore, a subsequent destination-choice model found that the level of resilience of a coastal community to flood hazards has a direct effect on visitation rates to these communities, suggesting that resilience improvements do not just affect infrastructure, but economic performance as well. This toolkit can greatly improve the transportation planning process to include preliminary resilience assessment that can compliment existing economic, social and infrastructure methods in one, concise program.