Water samples were collected in San Pablo Bay, Corte Madera Bay, and a tidal creek in Corte Madera Marsh between April 2022 and June 2023 to measure suspended-sediment concentrations and percent carbon of suspended sediment. The water samples were collected near the USGS instrument platforms (see time-series data page) with a peristaltic pump, via a Niskin sampler, or directly with a sample bottle.