Morphometry, spatial analysis and development of lakes on the Mackenzie Delta plain

The origin, development, and distribution of lakes on arctic river deltas and their relation to delta geomorphology are poorly understood. The purpose of this study was to develop a digital, automated system for accurate, georeferenced measurement of spatial properties of arctic delta lakes, to apply this to the Mackenzie Delta, N.W.T, and then to interpret the results and propose a conceptual model of lake development for the subaerial delta plain.; Several morphometric equations were translated into digital map algebra algorithms for use within a geographic information system (GIS). The algorithms were evaluated for redundancy, sensitivity to differences in spatial characteristics, and consistency over several sizes and rotations of test objects. The most reliable measures, shoreline complexity and lake elongation, were applied to a map of Mackenzie Delta lakes extracted from a Landsat Thematic Mapper image. Measures of lake density, average lake area, percent of area in lakes, and the distance of lakes from the delta head and the main distributary channel were also developed and applied.; Patterns can be explained by northward progradation of the delta front with simultaneous lake formation followed by thermokarst take development on the delta plain. Spatial variation of the results suggests the channel network affects lake development through a distance gradient of flood-related processes and must be considered in conjunction with distance from the delta head. The southwest upper delta is occupied by thermokarst lakes situated on the oldest part of the delta plain. The area south of Point Separation is dominated by a small number of point bar lakes typical of a highly active part of the delta. The middle and outer delta were more difficult to interpret due to the unknown effects of rising relative sea levels and enhanced thermokarst activity during the Holocene climatic optimum.