The Bay of Fundy's diurnal tides and the fractured bedrock of the Saint John region create a subsurface drainage environment that can mislead even experienced engineers. In the Saint John area, the interaction between the Carboniferous metasedimentary rock and the overlying glacial till demands precise hydraulic conductivity data, not just a look at the borehole log. A standard site investigation without field permeability assessments often misses the dominant flow paths that control excavation stability and foundation dewatering needs. At our accredited laboratory, the Lefranc method is deployed in granular overburden and residual soils, while the Lugeon test characterizes the rock mass fractures that are prevalent in areas like Millidgeville and along the Kennebecasis River valley. These direct measurements, aligned with ASTM D6391 procedures, provide the design parameters necessary to manage groundwater in this geologically complex coastal city of roughly 70,000 residents.
A Lugeon value above 10 in the Coldbrook Group metasediments near Saint John often signals open, tidally influenced fractures that require grouting before any deep foundation work.
