BOTTOM STRESS ESTIMATES AND SAND TRANSPORT ON NORTHERN CALIFORNIA INNER CONTINENTAL-SHELF

Measurements of velocities and light transmission in the bottom bounda ry layer on the continental shelf off northern California demonstrate the importance of storms in the transport of sediment along the coast and offshore in this region. Time-series estimates of bottom stress ob tained from a combined wave-current bottom boundary layer model in whi ch wave and current measurements from the Geoprobe tripod were used as input show high stress values of 10 dynes cm-2 during two distinct st orm events in early February and early March, 1991. These stresses ind uce significant offshore sediment transport, achieving maximum values of about 0.5 g cm-1 s-1. The net transport over the entire measurement period from 30 January 1991 to 13 March 1991 was along the coast towa rd the north and offshore. This transport pattern explains slow migrat ion of low amplitude, broad crescentic dunes along and across this por tion of the inner continental shelf.