The impact assessment studies comprise a formal process to predict the environmental consequences of human development activities and to plan appropriate measures to eliminate or reduce adverse effects and to augment positive effects.

EIA thus has three main functions:

• to predict problems,
• to find ways to avoid them, and
• to enhance positive effects.

The third function is of particular importance. The Environmental Impact Assessment (EIA) provides a unique opportunity to demonstrate ways in which the environment may be improved as part of the development process.

The EIA Directive (EU legislation) on Environmental Impact Assessment of the effects of projects on the environment was introduced in 1985 and was amended in 1997. Member States have to transpose the amended EIA Directive by 14 March 1999 at the latest. 

The EIA procedure ensures that environmental consequences of projects are identified and assessed before authorisation is given. The public can give its opinion and all results are taken into account in the authorisation procedure of the project. The public is informed of the decision afterwards.

EIA is a management tool for planners and decision makers and complements other project studies on engineering and economics. Environmental assessment is now accepted as an essential part of development planning and management. It should become as familiar and important as economic analysis in project evaluation.