lagoon morphodynamics

A new USC Sea Grant funded project with PIs Giddings and Pawlak is investigating the response of low-inflow estuarine lagoons to extreme events. Graduate student Madeleine Harvey is collecting the measurements and using this work as the basis of her PhD dissertation. Specifically, we are examining the physical response to extreme water levels (tides, waves) and runoff as these provide windows into future climate conditions. Extreme water level events in these estuaries can significantly impact the morphology, i.e., the shape of the lagoon, by moving large amounts of sediment and thus moving channels and banks, and even altering the height of the bed. These lagoons can completely close in response to import of sand from the beach. When the lagoons shut off from the ocean, circulation drastically changes and slows. This can lead to prolonged periods of hypoxia, or low oxygen conditions. This feedback between hydrodynamics (circulation) and morphology (shape) forms the basis of the processes we are trying to better understand. Please see the USC Sea Grant site for a project summary.

LosPen_mouthMorphology

These images are 1 day apart near low tide on 09 January 2015 17:00 and 10 January 2015 17:15 where the channel morphology shifted substantially. Thanks to the Tijuana River National Estuarine Research Reserve and the System-Wide Monitoring Program (SWMP), particularly Michelle Cordrey for data access and maintenance.