FY 1987

Measurements of benthic sediment erodibility in Puget Sound, Washington

Lavelle, J.W., and W.R. Davis

NOAA Tech. Memo. ERL PMEL-72, NTIS: PB87-208450, 32 pp (1987)

Rates of erosion of bottom sediment were studied at seven locations in Puget Sound, Washington. Fresh, unremoulded sediment from box cores was exposed to turbulence in a fluid chamber in which turbulence is generated by oscillating a perforated disk at controlled frequencies. Resulting time series of particulate concentration in the chamber at each stepped level of equivalent bottom stress were used to calculate estimates of erosion rates and deposition velocities. Resulting rates of erosion at 1 dyne/cm do not appear to be consonant with rates at higher stress, suggesting that a thin surficial layer of sediment is more easily eroded than sediment below. Differences of erosion rates among sites at stresses of 2 dynes/cm and above are not resolvable with the available data.