3.3.8 EIA Effectiveness
Opinions differ regarding the role played by EIA in decision making. It may be argued that by identifying the likely effects of a project at an early stage EIA can help improve the quality of planning and decision making. Ideally a properly conducted EIA should lead to rejection of environmentally unsound projects (Wood 1995). Mitigation can be planned based on the revelations by EIA so that the likely environmental effects of the human action are acceptable. As has been mentioned before, acceptability criteria for environmentally sustainable projects include complete impact compensation by means of conservation of total natural capital (weak sustainability criterion) and maintenance of assimilative capacity of the environmental sink resources.

EIA, per se, does not pre-empt the possibility of implementing a project with significant adverse environmental impacts. It only ensures that authorisation of such projects are done with full knowledge of environmental consequences.

EIA should be viewed both as science and art. The 'art' of EIA aims at aiding the decision-making process by attempting analyses of actions and consequent impacts. Identification, prediction and evaluation of environmental impacts fall in the realm of the 'science' of EIA

While the role of EIA as a key integrative element of the overall environmental policy cannot be over emphasised, it must be borne in mind that EIA takes place in a political context and therefore economic and social factors may at times assume greater importance.

There exists a considerable disagreement among EIA scholars regarding the essential elements of an effective EIA system. The EIA process however, is generally accepted as very important in determining the effectiveness of an EIA system.

This author is of the opinion that EIA may be considered effective if
* the revelations of EIA studies influence the decision making in a significant manner; and,
* the estimates of impacts and effectiveness of mitigation measures are within reasonable degree of accuracy.

3.4 EIA Methodology
As has been repeatedly emphasised in this thesis one of the principal objective of EIA is to help achieve an optimisation of resource utilisation so as to ensure environmental sustainability. The EIA procedures include an evaluation of many different things on a commensurate scale. This involves valuing aspects of environment through a series of objective and subjective routes (Gilpin 1994). Environmental impact may be defined as any change in the environmental system that can be attributed to human activities relative to alternatives under study for meeting a project need (Canter 1977). EIA methodologies provide an organised approach for predicting and assessing these impacts (Canter 1977). Such methodologies, also termed as EIA methods, attempt to assess collectively the results of the specific impact predictions in terms of an overall or summary evaluation (Rau 1980). Bisset (1983) argued in favour of a clear distinction between EIA methodologies. EIA techniques deal with gathering necessary data and information for an EIA study while the organisational principles of the EIA methodology adopted are employed for collating, arranging, presenting and sometimes interpreting the data generated.

Following the passage of the National Environmental Policy Act (1969) in USA numerous EIA methodologies have been developed. In fact during the early years, methodological aspects dominated the literature on EIA. EIA methodologies, although initially thought of as impact summarisation tools, can also be effectively applied to the following components of EIA process: -
* Identification of anticipated impacts.
* Description of the affected environment. Methodologies can be of particular use in identifying a finite number of environmental attributes that can provide an adequate description of the affected environment.
* Prediction and assessment of specific impacts.
* Systematic evaluation of alternatives.
* Summarisation and communication of EIA study results.

This study in a subsequent chapter presents a critical appraisal of EIA methodologies.
Tomlinson (1984) extended application of EIA methodology to screening. Beyond EIA, the methodologies can also be logically applied to environmental monitoring and post-evaluation of EIA effectiveness.

3.5 Environmental Impact Assessment: Origin and Development
The numerous stimuli in response to which EIA has developed as an approach to the evaluation of development actions included unforeseen harmful effects of large-scale development actions undertaken during the post-war period (Clark 1984). Also, as the human society, - at least in the developed world, transformed from modernism (characterised by production dominated activities) to post-modernism (characterised by dominant service generating activities) an upsurge in the environmental activism was witnessed.

Till the 1950s project appraisal studies were mainly on grounds of technical feasibility, financial viability and legal permissibility (Clark 1984, Smith 1993). As the post-war decades witnessed unprecedented growth in industrialisation the inherent weaknesses of such studies to address the increasing complexity, scale and implications of resource development were exposed threadbare.

3.5.1 Cost Benefit Analysis
Initial attempts to overcome the deficiencies of project appraisal methodology was through incorporation of (social) cost benefit analysis (CBA), which attempts to express all impacts in terms of resource costs valued in monetary terms. (Johansson 1993, Smith 1993, Clark 1984, Harris 1984). However, as highlighted by Pearce and Nash (1981), practical problems of using cost-benefit analysis for environmental decision making, inter alia, include the following:

1. It is often difficult, if not impossible, to attach prices to the environmental and natural resources by using market values. Artificial measures are undertaken by economists to allocate price to environmental and natural resources.

2. Even if monetary prices can be justifiably allocated to environmental resources such prices may not be of great significance in the real life situations involving uncertainty. The problem is further augmented due to imperfect information and an unequal distribution of income, wealth and power.

Other demerits of cost benefit analysis include the following:
1. Inability to account for the distributional aspects of costs and benefits and the problems of aggregation (Carley and Bustels 1984, Smith 1993).

2. Inability to account accurately for, and incorporate, such temporal changes as variations in interest rates, adequate discount rates and price levels (Smith 1993).

3. Inability to evaluate complex environmental interrelationships and the broader social issues of resource allocation (O'Riordan and Swell 1981).

Arguably cost-benefit analysis remains a good technique so long as its limitations are recognised and application is made with caution. However, this seldom was the case and in consequence pressures mounted to search for an alternative which led to the appearance of environmental impact assessment (Smith 1993).