THE OAK RIDGES MORAINE OF SOUTHERN ONTARIO - A GROUNDWATER RESOURCE AT RISK

Protection of ground-water resources is an emerging theme in many urba n areas. In south-central Ontario, the Oak Ridges Moraine (similar to 1400 km(2)) is a prominent glacial moraine complex on the rapidly urba nizing northern margin of the Greater Toronto Area and constitutes a m ajor regional aquifer system. Given the pre-eminent economic importanc e of the region, the ground-water resource can be argued to have provi ncial significance, and there is much current debate regarding the imp act of urbanization and other anthropogenic activities on ground-water quality and supply. Particular issues are the degree of acceptable fu ture development and the definition of the most environmentally and hy drogeologically sensitive areas. This paper reviews what is currently understood of the geology and hydrogeology of the Oak Ridges Moraine, and provides an overview of quantitative modelling studies.