Accurate representation of river systems within Earth System Models (ESMs) is essential for understanding and predicting hydrological processes. The choice of spatial discretization introduces uncertainties in capturing the river-land-ocean continuum. In this poster, we present a pioneering study on mesh-independent river modeling in the Sagavanirktok River Basin, utilizing the E3SM river model, MOSART. We assess the performance of the river modeling approach by comparing results obtained from a "unified" Model for Prediction Across Scales (MPAS) mesh, seamlessly integrating river, land, and ocean components, with an established configuration based on Advanced Terrestrial Simulator (ATS). By analyzing the impacts of spatial discretization on flow routing, we identify potential sources of uncertainties in the modeling process. This study provides insights into the implications of spatial discretization on river simulations and offers a foundation for improved river modeling and predictive capabilities. Furthermore, it opens opportunities for enhanced representation of complex hydrological dynamics in coastal regions.