Suspended-sediment concentration and grain size in the San Lorenzo River, coastal California

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.

This data release is related to two earlier products. This data release does not supersede the two earlier products because those also contain geochemical information. This data release contains suspended-sediment concentration and sand break data for samples mentioned in the two earlier products, and includes a longer measurement time frame. The two earlier products are:

Draut, A.E., Conaway, C.H., Echols, K.R., Storlazzi, C.D., and Ritchie, A., 2011, Suspended sediment and organic
contaminants in the San Lorenzo River, California, water years 2009–2010: U.S. Geological Survey Open-File
Report 2011-1120, 24 p. and data tables [http://pubs.usgs.gov/of/2011/1120/]

and

Campbell, P.L., East, A.E., Conaway, C.H., 2022, Polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations in the San Lorenzo River, Santa Cruz, California, USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9GB8YSZ.