This research team will create a transferable economic benefit-cost impact GIS tool to evaluate the ability of natural and nature-based features (NNBFs), such beaches, dunes, wetlands, living shorelines and seagrass beds, to change the extent, severity and probability of sea-level rise flooding impacts. The tool will compare transportation, tourism, infrastructure and quality-of-life economic costs associated with sea-level rise (SLR) impacts when NNBFs are not used in a community compared with the costs associated with reduced SLR impacts when they are. The project also will include a case study that applies the tool to Mobile, Alabama.

Objectives

The goal of this project is to create an Economic Benefit-Cost Impact GIS Tool to evaluate the ability of Natural and Nature-Based Features (NNBFs) to preserve coastal communities and businesses. We will achieve this goal through the following measurable objectives: (a) To develop high resolution hydrodynamic model that is able to quantify how different NNBFs will change the extent, severity, and probability of flooding due to SLR and extreme storms within a coastal community; (b) To quantify the impacts that NNBFs have on SLR flooding risk and severity; (c) To develop a transferrable GIS Tool that utilizes publicly available SLR, roadway, building infrastructures, and other spatial data to calculate (a) the economic costs associated with SLR impacts when NNBFs are not implemented in the community compared with (b) the economic costs associated with reduced SLR impacts when NNBFs are implemented in the community; (d) To provide a case study application of the economic impacts with and without NNBFs in Mobile, AL; (e) To coordinate among local partners to determine best practices associated with NNBFs.

Methodology

The project objectives are built upon two main hypothesis tests: (a) Do NNBFs influence the flooding characteristics of the areas in which they are built? (b) If NNBFs change flooding characteristics, are these changes substantial enough to change the community economic impact costs? This goal will be accomplished through the following tasks: First, we will quantify how different NNBFs will change the extent, severity, and probability of SLR flooding impacts within a coastal community by advancing an existing hydrodynamic model that can simulate flow dynamics in estuary. Second, we will create an updated EFDC+ hydrodynamic model that allows users to select, place and analyze different NNBFs in their community to generate and compare maps/ GIS layers of flooding. Third, we will create an innovative total economic cost impact cost calculation (improving upon FHWA and Rand Corporation methods) to quantify how the flooding map layers with and without NNBFs present will translate to community economic impacts. Finally, we will apply the tool to Mobile, AL to conduct an economic impact case study related to potential NNBF implementation and share the results through a workshop with our project partners.

Rationale

It is well documented that short- and long-term flooding associated with Sea Level Rise (SLR) continues to be a concern for coastal communities and business in Alabama and Mississippi. This flooding has the potential to lead to significant property and roadway damage, lost tourism, generated freight and personal traffic congestion, and reduction in residents’ quality of life. Over the past decade, many civil and environmental engineers have been studying Natural and Nature-based Features (NNBFs) as a sustainable means of absorbing and adapting to flooding. Unfortunately, there is little knowledge or guidance on where and what types of NNBF are most effective in terms of curbing the impact of inundation on coastal communities. Furthermore, it can be difficult to communicate these benefits of NNBFs with the local, regional and state decision-makers who would approve the construction of these features. Therefore, the goal of this project is to create an Economic Benefit-Cost Impact GIS Tool to evaluate the ability of Natural and Nature-Based Features (NNBFs) to preserve coastal communities and businesses by comparing how much an NNBF is saving the community in prevented economic loss versus the cost of the NNBF construction. We will achieve this goal through the following innovative objectives: (a) developing an innovative high resolution hydrodynamic models that quantify how different NNBFs will change the extent, severity, and probability of flooding due to SLR and extreme storms within a coastal community and (b) developing a transferrable GIS Tool that utilizes publicly available NOAA SLR, roadway, building infrastructures, and other spatial data to calculate the economic costs associated with SLR impacts when NNBFs are and are not implemented in the community.