GIS Spatial Modeling of Landscape and Water Systems in GTA, Canada

Modeling landscape with high-resolution digital elevation data (DEM) in a geographic information system can provide essential morphological and structural information for modeling surface processes such as geomorphologic process and water systems. This paper introduces several DEM-based spatial analysis processes applied to characterize spatial distribution and interactions of ground and surface water systems in the Great Toronto Area (GTA), Canada. The stream networks and drainage basin systems were derived from the DEM with 30-meter resolution and the regularities of the surface stream and drainage patterns were modeled from a statistical/multifractal point of view. Together with the elevation and slope of topography, other attributes defined from modeling the stream systems, and drainage networks were used to associate geological, hydrological and topographical features to water flow in river systems and the spatial locations of artisan aquifers in the study area. Stream flow data derived from the daily flow data recorded at river gauging stations for multi-year period were decomposed into “drainage-area dependent” and “drainage-area independent” flow components by two-step “frequency” and “spatial” analysis processes. The latter component was further demonstrated most likely due to the ground water discharge. An independent analysis was conducted to modeling the distribution of aquifers with information derived from the records of water wells. The focuses were given on quantification of the likelihood of ground water discharge to river and ponds through flowing wells, spring and seepages. It has been shown the Oak Ridges Moraine as a unique glacier deposit unit serves as a recharge layer and the aquifers in the ORM underlain by Hilton Tills and later deposits exposed near the steep slope zone of the ridges of ORM provide significant discharge to the surface water systems (river flow and ponds) through flowing well, springs and seepages.