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There is evidence for 10 mechanisms of sediment distribution in small lakes. The sediment accumulation rates measured from a common horizon in cores from 64 sites on Esthwaite Water, U.K., were used to determine the relative importance of these mechanisms on the distribution of sediment in the lake.River inflows generally produced localized effects but there were indications of periodic turbidity flows to the deepest point of the lake from the major inflow. Active sediment focusing processes were the dominant distribution mechanisms, a major resuspension of sediment at autumn overturn probably being the most important. The remaining variance was much greater than observed in similar work elsewhere, suggesting that redistribution of sediment by direct and indirect wave action may be taking placeall over the lakebcd during isothermal periods. The relative contributions of the different processes were corroborated by analysis of previously published sediment trap data.

Four processes are important in causing either sediment focusing or overestimation of sediment accumulation rates by traps, or both. A simple model to predict the occurrence of these events was constructed from published data for monomictic and polymictic lakes which contained sufficient detail to identify the major redistribution process. Boundaries between the regions where different mechanisms dominate were calculated from the expected mode of operation of the processes. The model was tested using sediment trap and accumulation rate vs. water depth data from the literature. Other published work is in general agreement with the predictions of the model.

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