Coastal Nature Based Solutions to Mitigate Flood Impacts and Enhance Resilience

Objective:

This project aims to develop an integrated modeling and stakeholder-informed framework to evaluate and guide the use of nature-based solutions (NBS) for mitigating compound flood risks in Mobile Bay under current and future climate conditions.

Approach:

"To assess the effectiveness of nature-based solutions (NBS) such as wetland restoration in reducing compound flood risks, we are developing a high-resolution, site-specific hydrodynamic model of Mobile Bay, Alabama. This model is being tightly coupled with upstream hydrologic models to simulate the joint influence of fluvial and coastal drivers on flood hazards. A comprehensive field campaign has generated a rich set of localized hydrologic, ecological, and geomorphic data that are essential for calibrating and validating the integrated model. The numerical framework allows simulation of historical storms, probabilistic return period events, and future climate scenarios.
Stakeholder engagement is a foundational component of this project. Through a co-development process involving agencies, practitioners, and non-governmental groups, we have hosted multiple engagement events to ensure that the modeling framework and priority scenarios are aligned with on-the-ground planning and mitigation goals. These efforts also support social science integration, enabling risk perception research and identifying barriers to NBS adoption. A novel compound flood risk index, combining depth, velocity, and duration, has been developed to enhance communication of risk and to assess the relative performance of different NBS interventions. Together, these elements create a decision-support system that is both scientifically robust and practically relevant."

Impact:

Abstract:

This project builds a decision-support framework for evaluating and designing nature-based solutions (NBS) that mitigate compound flood risks in Mobile Bay, Alabama. With coastal communities increasingly exposed to complex flooding from the combination of riverine discharge, storm surge, and sea level rise, effective planning tools that incorporate both natural infrastructure and stakeholder priorities are urgently needed. To address this gap, we are developing a high-resolution hydrodynamic model of Mobile Bay, coupled with hydrologic models and calibrated using an extensive dataset collected through field campaigns since 2022. These models simulate a range of scenarios—from historical storms to future climate projections—to assess the flood mitigation potential of NBS such as wetland restoration.

The core products of this research include:
- A coupled hydrologic-hydrodynamic-ecologic model of Mobile Bay tailored for compound flood analysis and response of wetlands to these forcings.
- A stakeholder-informed prioritization of NBS projects and scenarios, aligned with local planning objectives.
- A compound flood risk index that integrates depth, velocity, and duration of floods to communicate safety and exposure.
- A set of design guidelines for NBS implementation based on performance under compound flood conditions.

Today, flood mitigation planning often relies on siloed models, limited risk metrics, and sparse community engagement. This project overcomes these limitations by integrating scientific rigor with real-world context and input, using co-development to ensure outcomes are immediately useful for policy and planning. The impacts of this work include: (1) empowering communities and practitioners with credible data to support NBS adoption, (2) enhancing flood risk communication with a simplified but comprehensive flood risk index, and (3) enabling climate-resilient design strategies grounded in local needs and system dynamics. The approach directly supports CIROH research priorities across predictive modeling, hydroinformatics, and community response.