Sediment distribution and transport along a rocky, embayed coast: MontereyPeninsula and Carmel Bay, California

Field measurements of beach morphology and sedimentology were made along th e Monterey Peninsula and Carmel Bay, California, in the spring and summer o f 1997. These data were combined with low-altitude aerial imagery, high-res olution bathymetry, and local geology to understand how coastal geomorpholo gy, lithology, and tectonics influence the distribution and transport of li ttoral sediment in the nearshore and inner shelf along a rocky shoreline ov er the course of decades. Three primary modes of sediment distribution in t he nearshore and on the inner shelf off the Monterey Peninsula and in Carme l Bay were observed. Along stretches of the study area that were exposed to the dominant wave direction, sediment has accumulated in shore-normal bath ymetric lows interpreted to be paleo-stream channels. Where the coastline i s oriented parallel to the dominant wave direction and streams channels tre nd perpendicular to the coast, sediment-filled paleo-stream channels occur in the nearshore as well, but here they are connected to one another by sho re-parallel ribbons of sediment at depths between 2 and 6 m. Where the coas tline is oriented parallel to the dominant wave direction and onshore strea m channels are not present, only shore-parallel patches of sediment at dept hs greater than 15 m are present. We interpret the distribution and interac tion or transport of littoral sediment between pocket beaches along this co astline to be primarily controlled by the northwest-trending structure of t he region and the dominant oceanographic regime. Because of the structural barriers to littoral transport, peaks in wave energy appear to be the domin ant factor controlling the timing and magnitude of sediment transport betwe en pocket beaches, more so than along long linear coasts. Accordingly, the magnitude and timing of sediment transport is dictated by the episodic natu re of storm activity. (C) 2000 Elsevier Science B.V. All rights reserved.