Barriers to and opportunities for effective cumulative impact assessment within state-level environmental review frameworks in the United States

In the US, relatively little research has been done in recent years to inform the development and implementation of cumulative impact assessment (CIA) policy. Past studies have primarily focused on the requirements and practices of the National Environmental Policy Act, but little is known about the challenges and opportunities relating to CIA practices at the state level. By analysing data from a national survey of state environmental review programme administrators, this study identified the inability of state programmes to facilitate CIA practices as a major barrier to effective implementation, particularly reflected by the perceived lack of explicit procedures and data for conducting CIA. Important strategies for improvement included adopting detailed guidelines specifying what to include in an assessment and developing institutional mechanisms to encourage state agency co-ordination. Some differences in perception were observed across programmes due to the different types of state-level environmental review frameworks within which cumulative impacts are assessed. In addition, administrators from programmes without CIA requirements seemed to overestimate the cost and time needed to implement CIA. Changing their perception may contribute to the adoption of CIA procedures in these states.