Predictions of surficial sediment composition in the littoral zone of lakes

Lacustrine sediment focusing presumes the removal of fine‐grained littoral particles (silt and clay) to storage sites in the deeper, less productive zone of a lake. In the littoral zone, shorter term sediment storage, on the time scale of biological transfers, demands attention as these clays and silts represent potential vectors in aquatic contaminant transfers. Two empirical models that predict surficial fine‐grained sediment composition of the littoral were developed in Lake Memphremagog, Quebec. A 5‐variable model explained 67% of the variance in the proportion of clay at 62 nearshore sites. A 3‐variable model including measures of fetch, depth, and slope explained 58% of the variance while the additional variables of plant presence or absence and sediment organic matter contributed the remaining 9% of explained variation. The two models performed exceedingly well when tested at 41 sites not used in the original derivation of the model. Of these 41 test sites, 13 represent samples from littoral zones of five eastern Canadian lakes (maritime provinces) representing different geologies and morphologies.