UTILIZING PHOTOGRAMMETRY TO ANALYZE VARIATION IN THE LITHOLOGY AND STRUCTURE OF THE NIAGARA ESCARPMENT IN HAMILTON, ONTARIO, CANADA

The Niagara Escarpment is a major geomorphic feature in the northeastern U.S. and Ontario, Canada passing through southern Ontario and the northern states of New York, Michigan, Wisconsin and Illinois. The escarpment exposes Silurian aged rocks, primarily limestones, dolostones, shales and sandstones, which vary in structure and composition both vertically and along the length of the escarpment. The City of Hamilton, Ontario is divided and defined by the Niagara Escarpment, known locally as the “Hamilton Mountain”, as it separates the downtown core from upper suburban neighbourhoods. The presence of this feature has necessitated the creation and maintenance of access roads that climb up the escarpment, many of which were built almost 100 years ago. In recent years, a series of major rock falls and mudslides along the escarpment access roads have posed serious problems for transportation and have raised concerns about future erosion issues along the escarpment. Unfortunately, little is known about the rate of erosion, or susceptibility to erosion of the escarpment, or the factors that are contributing to the failure of the rock face which may include lithological variation, fracture patterns, and surface and groundwater movement. This study reports on methodologies that are now being utilized to efficiently map variations in bedrock lithology and structure, and the location of water seepage zones, at multiple locations along the Niagara Escarpment in the Hamilton region. Terrestrial-based photogrammetry and aerial photogrammetry collected using an unmanned aerial vehicle (UAV) have been employed to collect high resolution images of a number of study sites. High resolution three-dimensional outcrop models have been created using the remotely sensed data and will serve as a baseline for monitoring future erosion of the escarpment. The models will also be used to map fracture patterns, detailed variations in lithology and unit thickness across the city, and to identify surface and groundwater seepage zones. This study will report the methodologies used and preliminary results, of an ongoing investigation of the factors affecting erosion along the Niagara Escarpment in Hamilton, Ontario and has implications for the study of steep outcrop faces elsewhere.