Water samples were collected from the San Lorenzo River, Santa Cruz, California, and analyzed for suspended-sediment concentration and sand break (proportion of sand vs. silt-plus-clay) at the U.S. Geological Survey (USGS) laboratory in Santa Cruz, California. The samples were all single-vertical samples collected from the thalweg of the river, using a D-95 sampler deployed from a bridge box at a pedestrian bridge across the river in downtown Santa Cruz. All samples were collected from that location: 36.97565, -122.02322. The USGS acknowledges sampling permission granted by the city of Santa Cruz. Sediment concentrations and sand-break data are presented for use alongside stream-flow data collected by the USGS at gaging station 11161000, “San Lorenzo River at Santa Cruz”. The discharge data for gaging station 11161000 are separately accessible at https://waterdata.usgs.gov/ca/nwis/uv/?site_no=11161000. The discharge values associated with the suspended-sediment sampling reported here are provided so that users may easily reproduce the sediment rating curve.

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.

Water samples were collected in South San Francisco Bay and Whale's Tail South marsh tidal creeks from June 2021 through September 2021. The water samples were collected near pre-established USGS instrument moorings with a peristaltic pump, via a Niskin bottle, or directly with a sample bottle to analyze for suspended sediment concentration.

Water samples were collected in South San Francisco Bay and Whale's Tail South marsh tidal creeks from June 2021 through September 2021. The water samples were collected near pre-established USGS instrument moorings with a peristaltic pump, via a Niskin bottle, or directly with a sample bottle to analyze for suspended sediment concentration.

Suspended-sediment concentrations are reported in mg/L for water samples collected from the San Lorenzo River during the rainy seasons from 2008 to 2019. Samples were collected during 2-, 5- and 10-year flood events.

Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg piston sampler operated by Taber Drilling Company of Sacramento, California, and overseen by AECOM, Inc. Sediment was recovered using a split-barrel sampler and a rotary drill bit was added to the sampler where needed to penetrate coarse sediment. Samples from four boreholes are described in this data release: three sampled at multiple sediment depths (B2, B3, and B7) and a fourth (B4) from which only the topmost sample is included. Each borehole was drilled to the depth of apparent pre-dam alluvium or bedrock. Alternate sections were described and sampled; every second section was discarded without examination. Sediment samples were analyzed for grain size and charcoal abundance at the U.S. Geological Survey (USGS) laboratories in Santa Cruz, California. This data set complements data analyzed and presented by AECOM, Inc., for the Los Padres Alternatives Study Technical Memorandum prepared for the Monterey Peninsula Water Management District in October 2017 (https://www.mpwmd.net/asd/board/committees/watersupply/2018/20180123/02/Item-2-Exh-C.pdf). The USGS gratefully acknowledges collaboration with B. Kozlowicz of AECOM in the collection of these data.

Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg piston sampler operated by Taber Drilling Company of Sacramento, California, and overseen by AECOM, Inc. Sediment was recovered using a split-barrel sampler and a rotary drill bit was added to the sampler where needed to penetrate coarse sediment. Samples from four boreholes are described in this data release: three sampled at multiple sediment depths (B2, B3, and B7) and a fourth (B4) from which only the topmost sample is included. Each borehole was drilled to the depth of apparent pre-dam alluvium or bedrock. Alternate sections were described and sampled; every second section was discarded without examination. Sediment samples were analyzed for grain size and charcoal abundance at the U.S. Geological Survey (USGS) laboratories in Santa Cruz, California. This data set complements data analyzed and presented by AECOM, Inc., for the Los Padres Alternatives Study Technical Memorandum prepared for the Monterey Peninsula Water Management District in October 2017 (https://www.mpwmd.net/asd/board/committees/watersupply/2018/20180123/02/Item-2-Exh-C.pdf). The USGS gratefully acknowledges collaboration with B. Kozlowicz of AECOM in the collection of these data.

Water samples were collected in South San Francisco Bay and Whale's Tail South marsh tidal creeks from November 2021 through February 2022. The water samples were collected near pre-established USGS instrument moorings with a peristaltic pump, via a Niskin bottle, or directly with a sample bottle to analyze for suspended sediment concentration.

Water samples were collected in South San Francisco Bay and Whale's Tail South marsh tidal creeks from November 2021 through February 2022. The water samples were collected near pre-established USGS instrument moorings with a peristaltic pump, via a Niskin bottle, or directly with a sample bottle to analyze for suspended sediment concentration.

Water samples were collected in San Pablo Bay and Grizzly Bay on five days from January through June 2020. The water samples were collected from a small vessel near pre-established USGS instrument moorings using a peristaltic pump or a Niskin bottle. Data are provided in a comma-delimited values spreadsheet.