Building A Stormwater Flood Resilience Plan: Mapping to Mitigation

Objectives:
Communities are facing increasing stormwater flood risk driven by intensified precipitation, sea level rise, storm surge, urban development, and funding challenges. Many lack the tools and frameworks to develop holistic, effective, and actionable mitigation plans. This presentation will describe how to develop a stormwater flood resilience plan, providing communities with a roadmap to assess this risk and implement optimal, equitable, and actionable flood mitigation solutions.

Status:
The approach has been implemented in various municipalities across the US, customized to the specific needs and conditions in each community. Case studies in New York City, Virginia, and New Jersey will be presented.

Methodology:
The approach begins with the development of a stormwater flood risk map, leveraging hydrologic and hydraulic modeling. We will share guidance on adapting the model-building approach to the data and resources available and considerations on how to effectively share flood risk maps with stakeholders and the public. This is followed by an exposure and risk analysis that integrates the latest climate, modeling, and existing infrastructure data to assess and prioritize vulnerabilities. The presentation will cover how this step can be automated to facilitate efficient updates as new datasets become available. After the risk analysis we will present approaches to prioritize project locations and project types, leveraging additional datasets such as risk quantification, asset and infrastructure criticality, social vulnerability, community input, and economic indicators. We'll share dashboards typically created for this process to facilitate stakeholder engagement and support decision making. Using prioritized project locations, we'll describe the process for refining the model in these areas and developing solution concepts that can be used to develop project scoping and funding information, such as concept designs and cost estimates. Both cost estimates and risk quantification information can be used to develop a benefit-cost analysis (BCA). The BCA may be required for federal funding but also provides a policy and communication tool that helps communicate the need and justification for a given project and ensure strategic, cost-effective use of public funding. We will share additional automated tools that help conduct the BCA and are adaptable to each project based on the needs and data available. Finally, we will present public engagement strategies that have been used to ensure community-focused solutions. This methodology has been proven through multiple case studies, which will highlight key considerations and lessons learned for other municipalities interested in developing a stormwater flood resilience plan.

Findings:
Key findings demonstrate that integrating multi-dimensional data sets-such as H&H modeling results, climate projections, social vulnerability indices, and economic metrics-enables effective prioritization of projects and investments. Case studies from NYC, Virginia, and New Jersey illustrate how stakeholder engagement enhances the translation of data into actionable flood mitigation projects. These examples highlight scalable methods for combining technical methods with practical, equitable implementation strategies.

Significance:
This work provides critical guidance for municipalities and floodplain managers to adopt and implement Stormwater Flood Resilience Plans. By offering tools, methodologies, and real-world case studies, it equips communities to proactively address stormwater flood risks and adapt to evolving climate challenges. The insights shared foster collaboration and inform the development of resilient urban environments, ensuring sustainable and equitable solutions.