Summary

Any choice with a significant impact on the environment should, in principle, be the outcome of a political process reflecting the social preferences of everyone involved. Unfortunately, this ideal procedure requires a level of time and money that does not justify its application for planning each specific intervention. Different methods, mainly derived from traditional investment analyses, have been proposed for providing a rational basis for environmental decisions that cannot be analyzed through a public debate. These methods have proved inadequate, however, and are being replaced by Environmental Impact Assessment (EIA) as a less formal, but more applicable, method of incorporating environmental considerations in the decision process. Though the interpretation of EIA differs among various national and regional laws, it is now widely accepted as a potentially useful aid and is becoming a routine procedure for environmental planning and management in many countries. Computers can help to make EIA as explicit and repeatable as possible by supplying tools supporting its various phases. Information Systems (GIS) in the first screening phase, the development of mathematical models or expert systems to predict the impacts, and the use of multicriteria methodologies to support the final choice. Actual implementations of integrated computer systems that can be used throughout the decision process are also described.