Careful and thorough evaluation of the need for a project is of fundamental importance. The proposers of a project, be they politicians, government departments, ad hoc bodies, local authorities, private companies or individuals, may perceive a need which may not be shared or perceived by the local, regional or national community.

Fundamental questions must be asked and answered at the planning concept stage of a project, to ensure that the need is evaluated on a rational basis. Serious and costly mistakes are possible if such questions (as contained in Checklists 2 and 3, see Chapter 3) are not addressed at the earliest stage of a project. Engineers also have an important professional and environmental responsibility to question unclear motives and logic, omissions, possible misrepresentation of need and urgency, and possible unwise use of resources.

During the planning and design phases of a project many environmental issues will be raised. It is necessary to select relevant environmental effects and to determine in what detail they should be studied. This is the process of 'scoping'.

Scoping is used to determine whether an issue or impact (effect) is significant to the decisions affecting the project. It is important that the matters that are of concern to the authorities which issue statutory approvals be identified and specified. It is also important to identify and examine the issues or effects raised by other interested parties. Issues can be of a general nature (e.g. loss of recreational opportunities, increased traffic), in which case it is necessary to translate such issues into specific effects that can be studied. It is through the scoping procedure that peripheral issues can be rejected, and environmental assessment can become more cost-effective.

Scoping can be carried out in a number of ways. One way is through the use of a multi-disciplinary group assembled for the purpose. Another is through consultation with interested parties. Scoping will include:

• selection of effects to be studied
• agreement on effects to be studied
• geographical limits of the study
• selection of methods for measurement of effects
• selection of methods for evaluation of significance of effects
• agreement on methods and depth of study of issues
• identification of off-site and downstream effects and notification of these effects to relevant authorities if proponent does not have the responsibility for investigating or mitigating these effects.

As an example, an indicative selection of typical components for some particular types of project for which there may be environmental effects, is given in the accompanying tables. The categories of environment indicated are those described in Appendix 1.

These tables could form the basis for an environmental assessment matrix, as described in Section 7.7.