Event-driven sediment transport in two southern CA canyons
Vertical sediment fluxes in Hueneme and Mugu canyons were calculated from sediment trap
data collected during a 6-month mooring observation. Peaks of sediment flux, as high as
300+ g/m2/day, were recorded during winter storms in which high waves and river floods
often coincided. It was found that the wave-induced resuspension of shelf sediment, not the
river flood plumes, that provided the sediment for the raised sediment flux during winter
storms. The narrower canyon and shallower rims at the Hueneme mooring site outweigh its
longer distance from rivers (10 km from either Santa Clara River or Calleguas Creek) to
produce higher sediment fluxes at the Hueneme than at the Mugu mooring site, which is only
2 km from the Calleguas Creek. Turbidity currents and internal bores, observed in both
canyons, greatly increase the sediment fluxes, especially in the lower sediment traps at 30
meters above canyon floor.