Investigations of Hydrodynamics and Sediment Transport in the Monterey Bay National Marine Sanctuary

Abstract

The Monterey Bay Sediment Exchange Experiment (MOBSEE) is studying hydrodynamics, sediment movement, and water properties at a site on the inner shelf near Davenport to improve our knowledge of the pathways and processes of sediment transport in Sanctuary. A shallow-water environmental monitoring station roughly 400 m offshore in 12 m water depth measures currents, water levels, waves, bed level changes, temperature, salinity, water clarity, and material suspended in the water column every hour. This study has been collecting data for more than a year; the data set is not continuous, however, because of instrument failures and servicing time between deployments. The environment in which the instrument has been deployed is extremely energetic. Wave orbital flows near the bottom during storms are nearly 100 cm/s in the spring and summer; in the fall and winter these flows have greatly exceeded 100 cm/s. Combined with mean currents that can attain velocities greater than 20 cm/s, these flows transport large quantities of sediment and result in a very unstable seafloor. Individual storms can cause the seafloor to erode or accrete more than 10 cm. Additional results on water properties, hydrodynamics, and sediment transport magnitudes and directions are presented.

This abstract is from Monterey Bay National Marine Sanctuary Symposium, Sanctuary Currents '99, Climate Change and the Sanctuary, Poster Session, 1999.