Addressing significant impacts coherently in environmental impact statements

Determining if and why an impact is significant is a key task to inform decisions on the acceptability of a project through Environmental Impact Assessment (EIA). Hence, an Environmental Impact Statement (EIS) should be coherent in reaching conclusions about impact significance and in reverberating them in recommendations about mitigation. In this paper we present a procedure to analyze whether significant impacts are addressed coherently in an EIS, by analyzing if significance determination is grounded in information presented in the baseline and project description, supported by prediction of impact magnitude and if it unfolds into mitigation measures. In order to test the procedure, we applied it to two EIS selected from the International Finance Corporation's database. Results show that all impacts classified as significant were supported by information presented in the baseline and project description, as well as connected to corresponding mitigation measures. However, prediction of impact magnitude was not substantiated either on qualitative or quantitative methods. We argue that coherence in addressing significant impacts is one measure of EIS quality. If an EIS does not address its impacts coherently its reliability and credibility are impaired.