Mapping the nearshore substrates and hydrodynamics in lakes

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Cooley, Paul M.
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This study sought to better understand the spatial distribution of substrates in the nearshore area within and among six small lakes in the Precambrian Shield. For this task a new nearshore classification system (NSCS) and wave energy programs were developed. A GIS database containing detailed substrate, slope, and depth data, was compiled for 6 lakes. This multi-lake database containing 16 km of detailed substrate distribution data was used to describe and contrast the habitat structure of the lakes using a hierarchical classification system. Substrate diversity decreased with an increase with water depth. Substrate diversity was correlated with the shoreline development index which indicates the shape of shorelines are good indicators of aqueous habitat. Inter-lake statistical comparisons of the NSCS substrate data were prevented by the high inter-lake habitat diversity which has resulted from the erratic nature of glacial action and deposition in the region. However, by aggregating substrate classes, comparisons were possible at higher levels of the classification hierarchy. Spatial sediment dynamics were investigated in one lake by comparing the lower limit of the sub-surface wave base predicted from a maximum fetch model and the zone of offshore deposition from a detailed substrate map. (Abstract shortened by UMI.)