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The nature of environmental impact assessment

The nature of environmental impact assessment


Definitions of environmental impact assessment abound. They range from the oft-quoted and broad definition of Munn (1979), which refers to the need “to identify and predict the impact on the environment and on man’s health and well-being of legislative proposals, policies, programmes, projects and operational procedures, and to interpret and communicate information about the impacts” to the narrow UK DoE (1989) operational definition: “The term ‘environmental assessment’ describes a technique and a process b y which information about the environmental effects of a project is collected, both by the developer and from other sources, and taken into account by the planning authority in forming their judgements on whether the development should go ahead”. The UN Economic Commission for Europe (1991) has an altogether more succinct and pithy definition: “an assessment of the impact of a planned activity on the environment”.

Environmental impact assessment: a process

In essence, EIA is process, a systematic process that examines the environmental consequence of development actions, in advance. The emphasis, compared with many other mechanisms for environmental protection, is on prevention. Of course planners have traditionally assessed the impacts of developments on the environment, but invariably not in the systematic, holistic and multidisciplinary way required by EIA. The process involves a number of steps, as outlined in figure 1.1. These are briefly described blow, pending a much fuller discussion in Chapters 4 to 7. It should be clearly noted at this stage that, although the steps are outlined in linear fashion, EIA should be a cyclical activity, with feedback and interaction between the various steps. It should also be noted that practice can and does vary considerably from the process illustrated in figure 1.1. For example, current UK EIA legislation does not require some of the steps, including the consideration of alternatives, the post-decision monitoring (DoE 1989).

The order of the steps in the process may also vary.

  • Project screening narrows the application of EIA to those projects that may have significant environmental impacts. Screening may be partly determined by the EIA regulations operating in a country at the time of assessment.
  • Scoping seeks to identify at an early stage, from all of a project’s possible impacts and from all the alternatives that could be addressed, those that are the key, significant issues.
  • Consideration of alternatives seeks to ensure that the proponent has considered other feasible approaches, including alternative project locations, scales, processes, layouts, operating conditions, and the “no action” option.
  • Description of the project/development action includes a clarification of the purpose and rationale of the project, and an understanding of its various characteristics – including stages of development, location and processes.
  • Description of the environmental baseline includes the establishment of both the present and future state of the environment, in the absence of the project.

steps of EIA process

Figure 1.1 Important steps in the EIA process. Note: EIA should be a cyclical process with considerable interaction between the various steps. For example, public participation can be useful at most stages of the process; monitoring systems should relate to parameters established in the initial project and baseline descriptions.

Taking into account changes resulting from natural events and from other human activities.

  • Identification of key impacts brings together the previous steps with the aims of ensuring that all potentially significant environmental impacts (adverse and beneficial) are identified and taken into account in the process.
  • The prediction of impacts aims to identify the magnitude and other dimensions of identified change in the environment with a project/action, by comparison with the situation without that project/action.
  • Evaluation and assessment of significance seeks to assess the relative significance of the predicted impacts to allow a focus on key adverse impacts.
  • Mitigation involves the introduction of measures to avoid, reduce, remedy or compensate for any significant adverse impacts.
  • Public consultation and participation aims to assure the quality, comprehensiveness and effectiveness and effective of the EIA, as well as to ensure that the public’s views are adequately taken into consideration in the decision-making process.
  • EIS presentation is a vital step in the process. If done badly, much good work in the EIA may be negated.
  • Review involves a systematic appraisal of the quality of the EIS, as a contribution to the decision-making process.
  • Decision-making on the project involves a consideration by the relevant authority of the EIS (including consultation responses) together with other material considerations.
  • Post-decision monitoring involves the recording of outcomes associated with development impact, after a decision to proceed. It can contribute to effective project management.
  • Auditing follows from monitoring. It can involve comparing actual outcomes with predicted outcomes, and can be used to assess the quality of predictions and the effectiveness of mitigation. It provides a vital step in the EIA learning process.

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