The Integrated Coastal Modeling (ICoM) project brings together four programs within BER, namely Regional & Global Model Analysis (RGMA), Earth System Model Development (ESMD), MultiSector Dynamics (MSD), and Environmental System Science (ESS). This unique collaboration offers the opportunity to explore various facets of coastal science in an interdisciplinary setting that accounts for the complex, multiscale interactions among physical, biological, and human systems. In our ESS contributions to ICoM we consider coastal regions as comprised of a range of natural and engineered features that play a critical role in determining their resilience to various climate influenced drivers, including drought, sea level rise, storm surge, and shifting precipitation patterns. In this setting, the full coupling of high-fidelity process-based models of surface and subsurface processes is critical to developing a predictive understanding of how these systems function.  While high performance computing makes it possible to scale these simulations to large watersheds and river basins, equally important is the potential of this understanding to underpin advances in Earth system models and to support advances in operational models for MultiSector Dynamics.

To demonstrate this benefit of fully coupled high-fidelity process-based models in a natural system we used the Advanced Terrestrial Simulator (ATS) to study the impact of antecedent conditions on flooding through the response of the Harbeson watershed to a series of storms. This work highlighted that due to the slow drainage of the subsurface relative to the surface, even small storms may cause significant flooding, while topography may diminish the impact of storm surge.  Next, to continue exploring the natural system response we used the saltwater intrusion capabilities in the ATS to study the formation of ghost forests in the Delaware bay. This capability also supports studies related to salt marsh migration and the loss of agricultural land to saltwater intrusion. Finally, to study the engineered environment and its response to these drivers we highlight a prototype storm-drain network process kernel in the ATS that is coupled to its integrated hydrology model. This fully coupled system has the unique capability to not only capture the impact of the drainage network on flooding, but also the impact of green space or riparian zones. We demonstrate this new urban modeling capability in a synthetic setting.  In future work we will consider specific sites with data supporting green space performance assessments under flooding and storm drain networks inferred from publicly available data.