The Aquifer Vulnerability Index (AVI) is a method of assessing the vulnerability of aquifers to surface contaminants in Alberta. An aquifer is a geological formation that is permeable enough to transmit sufficient quantities of water to possible to support the development of water wells. In the assessment of aquifer vulnerability to potential contamination, the depth to the aquifer and the types of geological materials above them are considered. For example, aquifers closer to the surface overlain with pervious surface materials are more vulnerable to contaminants, as compared to aquifers found deeper and covered with a thick layer of impervious material. The AVI ratings indicate the potential of surficial materials to transmit water withy contaminants to the aquifer over a period of time. This data was created in 2002 using ArcGIS.