Environmental Impact Assessment

Environmental Impact Assessment

An environmental impact assessment is a systematic analysis of the potential impacts of proposed development projects on the natural and human environment (seeSOCIAL IMPACT ASSESSMENT), for identifying measures to prevent or minimize impacts prior to major decisions being taken and project commitments made.


Environmental impact assessment (EIA) originated in the United States under the National Environmental Policy Act of 1970 and is now among the most widely practiced ENVIRONMENTAL MANAGEMENT tools in the world. EIA was formally introduced in Canada in 1973 by the federal Environmental Assessment and Review Process (EARP). In 1992, the Canadian Environmental Assessment Act was proclaimed as law to replace EARP and to strengthen EIA in Canada. The Act came into force in 1995. EIA is also required under the law of the provinces and territories, and under various LAND CLAIM agreements in Canada's north. Municipalities and corporations are subject to the EIA requirements of their respective provincial, territorial or land claim jurisdictions, and are also subject to the Canadian Environmental Assessment Act if the federal government holds some decision-making authority concerning the proposed development or the acceptability of its impacts. Informally, EIA is increasingly becoming a routine part of the environmental management and auditing systems of municipalities and corporations.


The purposes of EIA are to ensure that projects do not cause significant adverse environmental effects and to encourage actions that promote SUSTAINABLE DEVELOPMENT. The Canadian Environmental Assessment Act sets out responsibilities and procedures for the EIA of projects for which the federal government holds decision-making authority, for example, a federal department's or agency's own project proposal; or project proposals on lands the federal government administers, provides funding to, or has some regulatory or permitting responsibility for. The kinds of projects involved include building an airport, funding or transferring lands for mining developments, establishing nuclear developments, dredging a harbour, constructing a fish ladder and all projects in NATIONAL PARKS.

EIA Process

The EIA process consists of a number of steps that are practised under more or less all EIA systems in Canada and internationally: i) a detailed description of the proposed project; ii) a screening process to determine whether an EIA is required; iii) a baseline study to identify past, present and future conditions against which the effects of the project will be assessed; iv) identifying and evaluating potential project effects; v) developing strategies to manage these effects; vi) a technical and public review of the information generated; vii) a decision as to whether the project should proceed and, if so, under what conditions; and, if the project is approved, viii) monitoring and managing actual outcomes. Early involvement of the public, and the public's sustained involvement throughout the process, is regarded as essential to good EIA.

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Further Reading

  • Kevin S. Hanna, ed, Environmental Impact Assessment: Practice and Participation (2005, second edition 2009); Bram F. Noble, Introduction to Environmental Impact Assessment: A Guide to Principles and Practice (2006, second edition 2010).

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