Methodology and Framework for Developing Groundwater FEFLOW Conceptual and Numerical Model to Couple with Mike 21 FM: Miami Beach Case Study

Sea level rise (SLR) is occurring in coastal environments and poses a major threat to communities and infrastructure. Cities along the eastern coast of the United States are currently being affected by SLR; thus, adaptation is crucial to assure resiliency. In Miami, FL, a large portion of densely urbanized areas within Miami-Dade County are experiencing major investments in infrastructure. Consequentially, the entire area is very vulnerable to effects of climate-change, such as SLR and hurricanes, among others.

Miami Beach, FL, is a quite interesting example to analyze considering that it experiences a lot of what was mentioned above. It is a densely urbanized coastal city that is exposed to extreme weather events, sea level rise, and its residents and infrastructure are in a very vulnerable position. Residential and commercial high rises, high end neighborhoods, and preserved historic buildings are the general makeup of the city. Moreover, highly permeable formations, shallow groundwater levels, rising sea levels, and tidal effects, create a perfect setting for saltwater intrusion (SI) to occur and worsen through the years.

As part of a larger study, a groundwater model is being developed for coupling with a surface water model with the purpose of assessing interactions between them. The City of Miami Beach (City) is the testbed for this study and the broader goal is to evaluate soft and hard engineering solutions for adapting to SLR. A comprehensive assessment and modeling of dike-subsurface barrier systems (DSBS) for adaptation in coastal areas, at various scales worldwide, as a function of coastal prevailing geology is carried out. The coastal geology of South Florida, where a highly porous limestone aquifer exists (i.e., Biscayne Aquifer), is one of the various settings to be considered.

For this portion of the study, the main goal is to delineate the methodology and framework to develop the groundwater conceptual model, generation of numerical model, data input process, boundary conditions applications, running, and results analysis processes. The numerical model is FEFLOW and this methodology follows the specific requirements for the model to be adequately suited for the coupling interface with the surface water numerical model, Mike 21FM.