The St. Clair Township site is well suited for a secure landfill operation for several reasons. First and foremost, is the layer of natural clay till, approximately 42 metres (140 feet) thick, on which the township is located. The clay is so resistant to the passage of water (permeability 10-7 to 10-9 cm/sec.) that hydrogeologists predict it will take hundreds to thousands of years for even a trace of contaminated material to travel through the natural barrier.
