Ground-penetrating radar survey: the search for the foundation remnants of the first Huron Street Public School

Ground-penetrating radar (GPR) uses the principle of scattering of electromagnetic waves to locate buried objects. This is a non-destructive and non-hazardous technique which aids in assessing archaeological, forensic, and geological sites. The purpose of this study was to detect the sub-surface remnants of the old Huron Street Public School which had been demolished in 1956. We assumed that the foundation of the old building still remains in its original location, which has since been turned into a playground. Our experiment was used to evaluate the feasibility of GPR for the required archaeological assessment of terrain before any construction can occur. GPR was used to image the subsurface of the Huron Street Public School's playground with an approximate area of 30 metres by 60 metres. The total area was divided into grids incorporating parallel lines approximately 10 metres apart that marked the starting point of GPR measurement. We found several prominent subsurface reflections that we concluded mark the foundation of the old building. Our results confirmed that the asphalted area of the basketball court differed significantly from the grass area in the radar sections. Small diffraction hyperbolas could be correlated to the position of trees and thus interpreted as roots. A strong reflector coming at 120 nanoseconds along one of the West-East lines of the study area was most likely the remnant of the old building's foundation, since its position appeared similar to that determined from a photograph of the school taken in the 1890s. The photograph was not used as conclusive evidence but rather as a guide. These findings of the school playground were promising and contributed directly to the main aim of this study. We suggest an in-depth survey covering a larger area to map the full extent of the old school building.