Surface-sediment grain-size distributions from the Elwha River delta, Washington, February 2016
Dates
Publication Date
2016
Date Collected
2016-02-16
Citation
Stevens, A.W., Gelfenbaum, G., Warrick, J.A., Miller, I.M., and Weiner, H.M., 2016, Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, February 2016: U.S. Geological Survey data release, http://dx.doi.org/10.5066/F7ZK5DTS.
Summary
This portion of the USGS data release presents sediment grain-size data from samples on the Elwha River delta, Washington, in February 2016 (USGS Field Activity Number 2016-608-FA). Surface sediment was collected at a total of 83 locations using a small ponar, or 'grab', sampler from the R/V Frontier in water depths between 1 and 17 m around the delta. An additional 18 samples were collected by hand at low tide. A handheld global satellite navigation system (GNSS) receiver was used to determine the locations of sediment samples. Grab samples that yielded less than 50 g of sediment were omitted from analysis and are classified as "no sample". The grain-size distributions of samples that yielded more than 50 g of sediment were determined [...]
Summary
This portion of the USGS data release presents sediment grain-size data from samples on the Elwha River delta, Washington, in February 2016 (USGS Field Activity Number 2016-608-FA). Surface sediment was collected at a total of 83 locations using a small ponar, or 'grab', sampler from the R/V Frontier in water depths between 1 and 17 m around the delta. An additional 18 samples were collected by hand at low tide. A handheld global satellite navigation system (GNSS) receiver was used to determine the locations of sediment samples. Grab samples that yielded less than 50 g of sediment were omitted from analysis and are classified as "no sample".
The grain-size distributions of samples that yielded more than 50 g of sediment were determined in the USGS Pacific Coastal and Marine Science Center sediment lab. Approximately 20 g of sediment was sub-sampled and 10 mL of 35% hydrogen peroxide was added to remove organic material in the sample. The sample was heated at 250 °C to remove any remaining hydrogen peroxide and was placed in an ultrasonic bath to liberate the fine fraction. Subsequently the sample was centrifuged for 1.5 hours to remove soluble salts. Samples were funneled through 2 mm and 63 um sieves to separate the gravel (>2 mm), sand (63 um to 2 mm), and mud (<63 um). The sand and gravel fractions were dried in an 80 °C oven and weighed. Five mL of sodium hexametaphosphate was added to the mud fraction and a 20 mL aliquot was taken from a 1 L graduated cylinder to determine the weight of the mud. The particle-size distribution of the mud and sand fractions was analyzed separately using a Beckman Coulter LS 13 320, and the gravel, sand, and mud results were integrated into a single grain-size distribution for each sample. The final grain-size data are provided in comma-separated ASCII format.
Data were obtained to assess the ecosystem response following the removal of two dams on the Elwha River. These data are intended for science researchers, students, policy makers, and the general public.
