Low inflow estuaries are prevalent throughout Southern California providing extensive ecological and human benefits. These systems have been drastically reduced and those that remain are heavily modified by human development. Thus it is unclear if these estuaries can maintain their roles contributing to habitat, biodiversity, carbon storage, and coastal protection. Most poorly understood is these systems response and resiliency to extreme events. Some work has shown that extreme events have the ability to drastically modify morphology and transition vegetation structure, yet the physics underlying these processes has not been studied, nor has the physical response of the hydrodynamics to these morphological changes. Thus we aim to explore in detail the coupled hydrodynamic/morphodynamic response of urbanized Southern California estuaries to extreme events in order to inform sustainable development and future adaptation. Specifically this project will investigate the relative importance of offshore waves versus stream flow in altering estuary mouth morphology (potentially closing the mouth) and circulation through in-situ observations of morphologic and hydrodynamic conditions.