Geological and Bioregional Assessments: assessing direct and indirect impacts using causal networks

The Geological and Bioregional Assessment (GBA) Program assesses the potential impacts of shale, tight and deep coal gas development on water and the environment. The cause-and-effect relationships that allow unconventional gas resource development activities to lead to an impact on environmental values are often interrelated, leading to both direct and indirect impacts. The GBA Program developed an impact assessment methodology based on causal networks that explicitly map out these cause-and-effect relationships, including all direct and indirect impacts. This network approach is coupled with a spatially explicit, systematic evaluation of the likelihood, consequence, control and mitigation strategy for each cause-and-effect relationship. Combining these evaluations based on the network structures identifies which activities could lead to potential impacts. The assessment identifies where more detailed local-scale assessments, management and monitoring should focus, as well as where impacts are unlikely to occur.