The Impact Assessment Acts (May 12)
Both NEPA and Act 250 require that assessment of impact be conducted prior to the implementation of a project OR a policy (in the case of NEPA). As you discovered, these assessment need to cover a wide variety of environmental aspects such a water quality, wildlife habitat, traffic, economic development, etc. While some of these topics are specified in the legislation, impact assessment is often not just limited to specified topics but can include many aspects of the concept of impact. If you look at actual Environmental Impact Assessments, the bulk of the assessments are about individual topics (such as impact on wetlands). Thus, these assessments are multidisciplinary in their approach. Much more difficult to achieve is an interdisciplinary and holistic assessment of the impacts of the project or policy. In addition, the really long-term impacts are also very difficult to assess.
The art and science of impact assessment is challenging, and not often agreed upon by all parties involved. Dispute then often moves the process to a adversarial one with mediation or court actions required. One outcome of all of this is that the project gets public scrutiny of some kind, possibly with press coverage. This takes the project into a political realm. So one major role of NEPA and Act 250 is just to make the project more visible.
In your comments, please comment on how available and helpful you find the information that you found (tell us what you found). Then, from the reading that you have done, reflect on how important you feel the Acts are and what you think they accomplish. If you didn’t look at an Environmental Impact Statement, the NEPA link goes to a selection of these often very long documents. You should just skim one or two to get a sense of what the document is like.