Hazard-specific Vulnerability Mapping for Water Security in a Shale Gas Context

Abstract

Northeast British Columbia (NEBC) is estimated to hold large reserves of unconventional natural gas and has experienced rapid growth in shale gas development over recent decades. This industrial development has the potential to impact the quality and quantity of surface water and groundwater. In this study, hazard-specific vulnerability mapping was conducted across NEBC to identify areas most vulnerable to water quality and quantity deterioration due to shale gas development activities. Vulnerability represents the combination of a specific hazard threat and the susceptibility of the water system to that threat. Hazard threats (i.e. potential contamination sources and water abstraction) were mapped spatially across the region. The shallow aquifer susceptibility to contamination was assessed using the DRASTIC approach, while the aquifer susceptibility to abstraction was assessed according to aquifer productivity. Surface water susceptibility to contamination was assessed on a watershed basis to describe the propensity for overland flow (i.e. contaminant transport), while surface water susceptibility to water abstractions was assessed using watershed runoff estimates. The spatial distribution of hazard threats and susceptibility were combined to form hazard-specific vulnerability maps for groundwater quality, groundwater quantity, surface water quality and surface water quantity. The vulnerability maps identify priority areas for further research, monitoring and policy development.