Highlighting action and environmental component interactions using a network theory approach

In Environmental Impact Assessment (EIA), the either positive or negative impacts that specific N project actions might generate on a number M of environmental components are typically summarized in the form of Interaction Matrix (IM). This is an NxM tabular array containing numbers whose sign and magnitude represent the type and severity of impacts. Current approaches to interpret the IM mainly remain on a qualitative level which are limiting its practical usage. In this work, we build on previous works and adopt network theory as a methodology to represent the IM in a graphical form, and to obtain quantitative information that can be inserted in the EIA. The IM corresponds to a bipartite network linking actions and environmental components. The associated network is useful to perform quantitative statistical analyses, which summarise the complexity of cross and mutual interconnections between actions and environmental components under simple and understandable metrics. We show some results from EIAs related to water projects and other case studies, whose different complexity helps to appreciate the general applicability of the method.