River Sensitivity in Coastal Modeling with SCHISM

The Unified Forecasting System (UFS) Coastal Applications Team (CAT) - Water Quantity (WQ) is a NOAA driven effort that focuses on the physical properties of two hydrodynamic models to provide support for the NOAA and NOS transition to a simplified modeling suite and insight on products that are employed by the marine navigation community. The New York Harbor and Long Island Sound are very significant regions for shipping and are both highly
trafficked. As a part of the UFS CAT WQ effort, teams are tasked with grid/mesh generation for this region and skill assessment of their chosen model. Throughout this effort, model results are highly dependent on the quality and nodal connectivity of a group's meshgrid. Here, we focus on the differences that mesh-grids can initiate in hydrological models and identify the importance of rivers with the most prominent discharge rates with the potential for nearshore current disruptions. If left unaccounted for in any hydrodynamic model, rivers have the potential to change the course of currents and resulting water quantity projections. However, including too much detail into the mesh and unnecessary rivers will increase the model cost. It is thus important to be able to create a baseline for which rivers will not be accounted for due to their small size or flow rate. Here, as one of the concurrent modeling works within the UFS CAT WQ effort, we use bathymetry data around the New York Harbor and Long Island Sound to create a mesh-grid that has a resolution small enough to account for the rivers flowing into these water regions, at a spatial resolution as high as 10 meters. Through iterations of the mesh, the sensitivity of the Semi-Implicit Cross-scale Hydroscience Integrated System Model (SCHISM) with regards to minor and major river discharge can be identified.