In the framework of an investment project for the Lachine Canal National Historic Site, reconstruction works were carried out on concrete walls in several sectors, namely a partially wooded industrial area and another one located close to a major arterial road. A study was conducted to evaluate the condition of existing concrete and ancestral masonry structures, in order to issue recommendations regarding rehabilitation options. During the work planning phase, the proposed solutions were evaluated based on the necessity of minimizing the impacts on the watercourse, vegetation, fauna, vehicular traffic, as well as the site’s archeological potential. Tridimensional modelling and several types of surveys were carried out in order to reproduce the original linearity of the heavily damaged walls.