Impact prediction, evaluation and mitigation - Introduction to Environmental Impact Assessment - page 144

the nature of the methods used may vary, for example, according to the number of
alternatives under consideration, according to the level of aggregation of information and
according to the number and type of parties involved (e.g. “in-house” and/or “external”
consultation).
Evaluation methods can be of various types, including simple or complex, formal or
informal, quantitative or qualitative, aggregated or disaggregated (see Maclaren &
Whitney 1985, Voogd 1983). Much, if not most, current evaluation of significance in
EIA is simple and often pragmatic, drawing on experience and expert opinion rather than
on complex and sophisticated analysis. Table 5.3 provides an example of key factors used
in Western Australia, where there is a particularly well-developed
Table 5.3 Determinants of environmental
significance
Environmental significance is a judgement made by the Authority (West Australian Environmental
Protection Authority) and takes into consideration the following factors:
(i) the extent and consequences of biophysical impacts;
(ii) the environmental value of the area affected;
(iii) the extent of emissions and their potential to unreasonably interfere with the health, welfare,
convenience, comfort or amenity of people;
(iv) the potential for biophysical impacts of the proposal to significantly and adversely change
people's social surroundings;
(v) the extent to and the rigour with which potential impacts have been investigated and described
in the referral, and the confidence in the reliability of predicted impacts;
(vi) the extent to which the proposal implements the principle of sustainability;
(vii) the ability of decision-making authorities to place conditions on the proposals to ensure
required environmental outcomes are achieved; and
(viii) the likely level of public interest, and the extent to which the proponent has consulted with
interested and affected parties and responded to issues raised.
( Source: West Australian Environmental Protection Authority 2002.)
EIA system (see Chapter 10 also). To the factors in Table 5.3 could also be added scope
for reversibility. The factor of public interest or perception ((viii) in Table 5.3) is an
important consideration, and past and current perceptions of the significance of particular
issues and impacts can raise their profile in the evaluation.
The most formal evaluation method is the comparison of likely impacts against legal
requirements and standards (e.g. air quality standards, building regulations). Table 5.4
illustrates some of the standards which may be used to evaluate the traffic noise impacts
of projects in Britain. Table 5.5 provides an example of more general guidance on
standards and on environmental priorities and preferences, from the European
Commission, for tourism developments. Of course, for some type of impacts, including
socio-economic, there are no clear-cut standards. Socioeconomic impacts provide a good
example of “fuzziness” in assessment, where the line between being significant or not