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close this bookConducting Environmental Impact Assessment in Developing Countries (United Nations University, 1999, 375 p.)
close this folder3. EIA process
View the document3.1 Introduction
Open this folder and view contents3.2 Principles in managing EIA
View the document3.3 Framework of environmental impacts
Open this folder and view contents3.4 EIA process in tiers
View the document3.5 Resources needed for an EIA
Open this folder and view contents3.6 Some illustrations of EIA processes in various countries
View the documentFURTHER READING

3.3 Framework of environmental impacts

EIA is based on understanding how the natural world functions, and how social, technological, and economic forces interact with the environment and resources issues. An understanding of the natural process allows the prediction of the consequences of development, which is the essence of EIA.

Any simplification of the EIA system, such as neglect of an important component, could lead to inaccurate assessment prediction and inaccurate identification of mitigation measures. For example, in assessing a proposal to clear a wetland, it could be noted that a mangrove forest may protect a shore area against storm surges, thus assuring an ideal habitat for fish spawning. Partial or incomplete assessment should be avoided. For example, an oil-fired thermal generating plant would require oil transport and storage. Sewage treatment also means sewage sludge disposal, in addition to the disposal of treated wastewaters.

Impacts may be considered as interactions between the project and the environment. Impacts are essentially changes to the environment. In other words,

[ Project] + [Environment] → {Changed Environment}

Predicting the likely environmental changes, given the project setting and the site description, is the task of EIA. One of the approaches to understand project-environment interactions is to follow the principle of decomposition. The idea here is to decompose the project into activities and the environment into components. Generally, the environmental components may consist of a large number of terms which may enable the description of any site to a reasonable extent.

Project activities, on the other hand, may be rather specific to the project type. (More discussion on the setting up of the activity-component framework is described in Chapter 4.)

As the project consists of a number of activities and the environment consists of several components, we may make following representations.


[Project] = (Activity)1, (Activity)2, ... (Activity)n


[Environment] = (Component)1, (Component)2,... (Component)n

the impact relationship becomes,

(Activity)i(Component)j → (Impact)ji

where (Impact)ji denotes the impact on the jth component due to the ith activity. (Impact)ij is essentially an issue requiring a further inquiry or examination.

To illustrate this concept, let us consider project-environment interactions for a thermal power plant proposed near a coastal area. In this case, the activity component description may take a form such as:

[Thermal Power Project] =

(site acquisition), (site clearance), (construction of plant including utilities), (movement of equipment and construction materials), (erection and commissioning trials), (power generation), (fuel transport), (fuel rejection), (waste heat release), (waste emission release), (solid waste release), (employment), (power distribution), (power tripping and plant shutdown and start up).

[Coastal Environment] =

(coastal water quality), (marine life, e.g., fisheries), (coastal recreational use), (mangroves), (terrestrial vegetation), (coastal air quality), (land use and landform), (employment), (per capita income), (societal risk).

The typical impact interaction elements of the activities and components listed above are essentially (Impact)ji elements. An activity such as waste emission release may be associated with the environmental component of coastal air quality to speculate an impact. Another example could be that of the activity of waste heat release, which may be associated with an impact on the environmental components of coastal water quality. Marine life or fisheries may be affected by the discharge of the waste streams and thus the income of fishermen who depend on the fisheries may change. On the positive side, power generation may be considered as an activity leading to employment benefits and an increase in the per capita income.

In the case of a positive impact issue, efforts need to be made to further enhance the benefits or at least ensure that the benefits are realized by evolving management systems. However, in the event of an undesirable impact issue, it becomes necessary to assess the significance of the issue and look for suitable mitigation measures or even alternative project plans, technologies, and locations.

A wide range of measures are proposed to prevent, reduce, remedy, or compensate for each of the adverse impacts evaluated as significant. Possible mitigation measures include:

• changing project sites, routes, processes, raw materials, operating methods, waste disposal routes or locations, or engineering designs;

• introducing pollution controls, monitoring, phased implementation, landscaping, personnel training, introducing social services, or public education;

• offering (as compensation) restoration of damaged resources, money to affected persons, concessions on other issues, or fit site programmes to enhance some other aspects of the environment or quality of life for the community.

All mitigation measures cost something, and this cost must be quantified too. Because of the imposition of the mitigation measures, the "impact equation'' becomes:

(Activity)i (Component)j → (Impact)ji → (Prediction and Assessment)
→ Mitigation Measures → (Residual Impact)ji

Assessment evaluates the predicted adverse impacts to determine whether they are significant enough to warrant mitigation. Prescription of the mitigation measures in many cases leads to either add-on systems or in some cases a major reformulation of the project. The cost of the project also escalates.

There are the following possibilities in such an analysis:

• impacts are impossible to assess considering state of the art (alternatives need to be assessed at the project and location level);

• impacts are difficult to assess as more information and/or skills are needed (specific and detailed studies around the identified issue need to be carried out);

• impacts can be assessed but the available mitigation measures do not lead to total alleviation of impact, so the residual impacts are still at a non-acceptable level (either more studies are needed to understand the impact and its mitigation or additional mitigation measures need to be sought or both);

• impacts can be assessed and fully mitigated (adequate specification and translation of the mitigation and monitoring systems needs to be evolved).

Thus, an activity-component framework helps to prepare a sound impact framework for further analysis. To achieve effectiveness in the practice of EIA the impact framework, described above, has been translated into a formal and structured process of "tiers''.