Estimation of the in-situ settling velocity of particles in lakes using a time series sediment trap

1. We outline a simple method for estimating the in-situ settling velocity of particles in wind disturbed lakes. The total sedimentation rate (primary and secondary sedimentation) was measured during storm events in two lakes using a time series sediment trap. 2. The sediment trap had 12 sample bottles which were programmed to open for periods of 3-4 h, giving total deployment times ranging from 36 to 48 h. 3. Wave mixed layer theory was used to infer if and when sediment resuspension occurred and the first order rate equation was used to estimate the settling velocity of resuspended particles. 4. The settling velocity during three resuspension events in Lough Neagh and one in Lough Macnean were 34.3, 29.5, 24.1 and 77.3 m day(-1), respectively. These are similar to values obtained using recent in-situ video imaging in marine environments, but much larger than previous lake sediment trap studies.