Sediment grain size at river outlets along the California coast

Fluvial sediment samples were collected from the lowermost reaches of 21 coastal watersheds in California, in order to characterize surficial grain size of river sediment from deposits that appeared to be recent based on field context. Samples were collected using a trowel to sample the uppermost 10 cm of sediment. Sampled locations included river-deposited sediment, upstream of tidal influence. Samples excluded coarse gravel and cobble grain sizes, if present. The watersheds selected for sampling have relatively little urban land use and no other recent data available on their fluvial sediment grain size. Sediment samples were analyzed for grain size at the U.S. Geological Survey (USGS) laboratory in Santa Cruz, California. The USGS gratefully acknowledges sampling permission granted by California State Parks.