Environmental impact assessment (EIA) is a policy and management tool for both planning and decision-making. EIA assists to identify, predict, and evaluate the foreseeable environmental consequences of proposed development projects, plans, and policies. The outcome of an EIA study assists the decision maker and the general public to determine whether a project should be implemented and in what form. EIA does not make decisions, but it is essential for those who do.
Environmental assessment (EA) refers to an understanding of the present status of environmental impacts and a study of how to manage them. An environmental impact statement (EIS) is the final step of an EIA/EA exercise where the conclusions of the assessment are put out in a communicable form to the concerned developer or authority. There is thus a distinction between the terms EIA, EA, and EIS.
A frequent opinion is that an EIA should usually only examine or look into the possible negative consequences of a project on the environment. Any positive issues emerging from the development are taken as stated by the project proponent or the developer. However, EIA is not restricted or biased to the examination and mitigation of negative impacts alone. EIA can also look into the possible positive issues due to the developmental projects and explore or suggest ways of enhancing them further by carrying out modifications in the project.
EIA is generally the responsibility of the project proponent and is often prepared with the help of external consultants or institutions, i.e., the EIA practitioners. In some cases, an independent commission is responsible for ensuring quality control throughout the implementation of the impact assessment, for setting appropriate terms of reference, and/or for the external review. The EIA study should be carried out by a multidisciplinary team comprising civil engineers, water supply and sanitation engineers, planners, chemists, life scientists, and socio-economists.
The agency responsible for receiving the impact assessment report and taking any subsequent action, i.e., the implementing agency, will usually indicate how the study is to be carried out and how the results should be used in the decision-making process. The institutional structures and agencies responsible for the management and implementation of EIA vary amongst countries, reflecting different political, economic, and social priorities. Mostly, they include local government agencies, NGOs, research institutions, and affected groups feeding into a specialist environmental unit within the implementing agency.
Apart from all these agencies, the general public is also involved in the process of EIA. Ideally public opinion should be solicited through public hearings arranged for the purpose of discussing the impacts of the project
Justifying an environmental assessment:
The following development activities justifying an environmental assessment
large industrial and manufacturing plants;
large construction projects - deep draught ports, highways, airports;
water resources structures - dams, irrigation systems;
large-scale intensified forestry, fisheries, or agriculture;
tourism facilities;
military facilities;
large-scale changes in land use.
EIA processes fall into four tiers:
EIA is generally conduced in tiers. In most countries, EIA processes fall into four tiers:
Screening: decides whether the EIA process is applicable at all to the development project. Screening should basically "clear'' all those projects where there are no major negative impact issues.
Scoping: helps in understanding the extent of environmental impacts and identifies significant environmental issues for further study. In the activity-component framework, this would mean that scoping should assist in the identification of impacting activities and impacted environmental components for all major negative impact issues.
Initial environmental examination: assesses the severity of the significant issues and finds ways to mitigate or enhance environmental impacts by considering the available information from past experience or the standard operating practices (SOPs; standard mitigation measures).
Detailed or comprehensive EIA: carries out a detailed examination of impacts by conducting relevant surveys. Studies are monitored by applying more rigorous impact evaluation/prediction tools where necessary and ensuring the effectiveness of the mitigation and enhancement measures. Detailed EIA thus focuses on impacts which are critical but not fully understood.
In a tiered EIA process, such as that above, the relevant regulatory agency decides whether there is nothing to be concerned about, or that the evaluation should proceed to the next tier.
Conducting EIA in tiers helps optimize the resources as well as to increase the effectiveness of the exercise by maintaining a better focus. Another advantage of a tiered approach is that the extent of the inquiry or examination expands with the advancing development of the project plans. Such a tiered process is most suited for developing countries which are in the rapid phase of development.
