After reading this article you will learn about: 1. Meaning of EIA 2. Issues in EIA Process 3. Process 4. Impact Evaluation Methodology.
Meaning of EIA:
Environmental Impact Assessment (EIA) can be described as a process of identifying the likely consequences for the bio-geophysical environment and for man’s over all interest with respect to implementation of particular developmental activities and also to find out alternatives of developmental proposal.
Thus, EIA is a process having the ultimate objective of providing decision makers with an indication of the likely consequences of their action.
EIA is no longer seen as an “add-on” process. Indeed the greatest contribution of EIA to environmental management may well be in reducing adverse impacts before proposals come through to the authorisation phase. EIA has been regarded as both ‘science’ and ‘art’ reflecting the concern both with technical aspects of appraisal and the effects of EIA upon the decision making process.
An Environmental Impact has both spatial and temporal components and can be described as the change in an environmental parameter, over a specified period and within a defined area, resulting from a particular activity compared to the situation which would have occurred had the activity not been initiated (Fig. 24.1).
The outcome of an EIA is usually some formal document called Environmental Impact Statement (EIS). In general a major deficiency of EIS has been the failure to establish a time frame indicator when impacts are likely to be manifested. Impact are also site specific and determination of their spatial distribution is also important. Of course spatial aspects are usually considered more adequately than temporal ones.
In general in an EIA, there is a major emphasis given on scientific and technical aspect of environmental changes connected with the proposed development programme. There is growing concern about the need for social scoping in very early in the assessment process.
The compromise relationship between the subjectivity of value judgment and the objectivity of the scientific approach is largely a function of the relative importance of the role of science at various stages in the sequence of impact assessment activities (Fig. 24.2).
Major Issues in the EIA:
The design of effective EIA procedures can be envisaged as the search for mechanisms to deal with issues generated by the need to juxtapose the planning and authorisation of proposals. Some issues deal with technical matters such as impact identification and prediction and other related to the management of information.
There are four major issues that needs to be addressed in the EIA process:
1. Identification of project requiring EIA.
2. Identification of impacts to be assessed.
3. Assessment of impacts.
4. Completion of an appraisal with proper objectivity.
Land use planners have long assigned that all development proposals should be subject to environmental appraisal, the level of analysis being commensurate. EIA, however, implies a special type of analysis involving a careful, thorough and detailed analysis of the likely implications of a development.
Many countries have developed lists of projects which should be subject to EIA. The main consideration is drawing up in such lists are project type, size and the consequence of likely impacts.
Many of the impacts of a proposed development may be trivial or of no significance to the decisions which have to be taken. In practice, a decision will generally turn upon only a small subject of issues of overwhelming importance. Scoping is the process for determining which issues are likely to be important.
Several groups, particularly decision makers, the local population, and the scientific community have an interest in helping to delineate such issues which should be considered and scoping is designed to camas s their views.
A clear distance should be drawn between techniques for predicting individual changes, such as Guassian dispersion models with which likely ground level concentrations of atmospheric pollutants can be calculated and EIA methods used in assessment. EIA methods are used for various activities, viz. impact identification, prediction, interpretation and communication and in devising post-project monitoring schemes.
The final decision with respect to project authorisation may appear a logical point at which is an appraisal terminated. EIA should be characterised by a stream of data collection and analysis running from information on environmental status at the outset, baseline data, through a gradual process of refinement and augmentation during impact prediction to the collection of data on actual impacts.
Post implementation, that is monitoring, data can be used either to refine the proposal, perhaps by the inclusion of additional remedial measures and the relaxation of constrains found to be unnecessary restrictive or to modify the decision. In the most extreme case, it may be necessary to remind authorisation if predictions severely underestimate adverse impacts, then likely impact in the long-run will be disastrous.
The EIA process should then allow for the communication of this information to:
(a) The project proponent
(b) The regulatory agencies, and
(c) All stakeholders and interest groups.
Process of EIA:
The structure of an EIA process is dictated primarily by the need to accommodate each of the key issues discussed above. Although there may be variations in the detailed procedures, adopted within a particular country, most systems in essence conform to the pattern shown as a broad outline of an EIA system (Fig 24.3).
From technical point of view, an EIA can be thought of as data management process.
It has three components:
First, the appropriate information necessary for a particular decision to be taken must be identified and possibly collected;
Secondly, changes in environmental parameters resulting from implementation must be determined and compared with the situation likely to occur without the proposal;
Finally, actual change must be recorded and analysed.
Determining the priority value of society with respect to the potential effects of a particular development proposal is a major concern. There are various issues, which are of concern irrespective of the approach to scoping which is adopted.
ii. Baseline Studies:
Baseline studies are perhaps the most commonly recognised and yet least understood element of EIA. The term usually refers to the collection of background information on the environmental components physicochemical, biological and physiographic information’s including socio-economic setting for a proposed development project and it is normally one of the first activities undertaken in an EIA.
As baseline data describes the existing environmental status of the identified study are the site specific primary data should be monitored for the identified parameters and supplemented by secondary data if available.
iii. Impact Prediction:
Impact prediction is a way of ‘mapping’ the environmental consequences of the significant aspects of the project and its alternatives. Environmental impact can never be predicted with absolute certainty and this is all the more reason to consider all possible factors and take all possible precautions for reducing the degree of uncertainty.
iv. Assessing Alternatives:
For every project possible alternatives should be identified and environmental attributes should also be compared. Alternatives should cover both project location and process technologies. Alternatives should consider ‘no project’ option also. Alternative should then be ranked for selection of the best environmental option for optimum economic benefits to the community at large.
Once alternatives have been reviewed, a mitigation plan should be drawn up for the selected option and is supplemented with an Environmental Management Plan (EMP) to guide the proponent towards environmental improvements. The EMP is a crucial input to monitoring the clearance conditions and therefore details of post- project monitoring should be included in the EMP.
An EIA report should provide clear information to the decision maker on the different environmental scenario without the project alternatives. Uncertainties should be avoided in the EIA report. There were a number of methods adopted for EIA impact evaluation.
The methods were checklist, matrix, network, overlay and Battelle approach. Each of the method has its own merits and demerits. However, in most cases matrix method was used for impact prediction purpose. In some EIA, risk assessment and disaster management plan also has to be prepared along with the EIS report. Otherwise project may not be cleared by the EIA appraisal authority in due course.
Impact Evaluation Methodology:
From the Table 24.2, it appears that for most of the project’s impact evaluation, matrix system is suitable and widely used. Quite considerable numbers of matrix system were known in recent years. Among the different matrix method Leopold method and method from Lohani and Thanh are widely used.
A case study example of a hydroelectric projects impact evaluation is given below:
1. Ad Hoc:
These methodologies provide minimal guidance for impact assessment beyond suggesting broad areas of possible impacts (e.g., impacts upon flora and fauna, lakes and forests), rather than defining the specific parameters within the impact area which should be investigated.
2. Simple Checklist:
These methodologies present a specific list of environmental parameters to be investigated for possible impacts, or a list of agency activities known to have caused environmental concern. They may have considerable value when many repetitive actions are carried out under similar circumstances. They do not, themselves, establish a direct cause- effect link, but merely suggest lines of examination.
These methodologies rely upon a set of maps of project area’s environmental characteristics (physical, social, ecological, aesthetic). These maps are overlaid to produce a composite characterisation of the regional environment.
Impacts are identified by noting the congruence of inherently antagonistic environmental characteristics within the project boundaries. The Geographic Information System (GIS), is modern development of this method.
The matrix methodologies incorporates both a list of project activities and a checklist of potentially impacted environmental characteristics. In a way, the matrix presents both alternatives from the checklist approach (i.e., both attributes and activities) to be considered simultaneously.
The two lists are then related in a matrix which identifies cause and effect relationships between specific activities and impacts. Matrix methodologies may either specify which actions impact which environmental characteristics or may simply list the range of possible actions and characteristics in an open matrix to be completed by the analyst.
These methodologies work from a list of project activities to establish cause-condition- effect relationships. They are an attempt to recognise that a series of impacts may be triggered by a project action. Their approaches generally define a set of possible networks and allow the user to identify impacts by selecting and tracing out the appropriate project actions.
6. Combination Computer-Aided:
These methodologies use a combination of matrices, networks, analytical models and a computer-aided systematic approach to:
a. Identify activities associated with implementing major federal programs;
b. Identify potential environmental impacts at different user levels;
c. Provide guidance for abatement and mitigation techniques;
d. Provide analytical models to establish cause-effect relationships to quantitatively determine potential environmental impacts;
e. Provide a methodology and a procedure to utilise this comprehensive information in responding to requirements of EIS preparation.
7. Battle Environmental Evaluation System (BEES):
This is a quantitative evaluation system based on assumed values of environmental quality.
In recent years however, a new type of ‘Environmental Evaluation System’ is often implemented. This is called “Battele Environmental Evaluation System” (BEES). This process involves identification of environmental parameters likely to be affected by project implementation, estimation of resulting changes in the selected parameters and aggregating the changes in determining resultant environmental parameters likely to be affected by project implementation, estimation of resulting changes in the selected parameters and aggregating the changes in determining resultant environmental quality.
Thus, this process necessitates transformation of parameter estimates into Environmental Quality (EQ) on a scale ranging from zero to one. Such a transformation is achieved through value function graphs which provide functional relationships between the parameter estimates and environmental quality scale.
In addition as each of the selected parameter represents only a part of the total environment, weights are assigned to the parameters to reflect their relative importance for ascertaining impact of the project on natural and socio-economic environment.
These weights are verified by an interdisciplinary expert team using ranked pair-wise comparison technique and expressed as Parameter Importance Units (PIU). A total of 1000 ‘PIU’s are allocated amongst all the parameters.
For evaluation of impact of project on environment, an index expressed as Environmental Impact Units (EIU) has been estimated for three alternative environmental conditions, viz the baseline without project, project without Environmental Management Plan (EMP) and project with EMP.
The index value is the summation of the product of EQ and PIU for individual parameters for above three alternatives as follows:
where, EIU = Environmental Impact Unit for i th environmental condition
n = Number of parameters consider for environmental impact evaluation
EQi = Environmental quality for i th parameter
PIUi = Parameter Importance units for i th parameter
The inference regarding impact of project is drawn on the basis of extent of positive or negative changes obtained in EIU from the difference in EIU of project with EMP and the EIU for baseline Environmental conditions. EIU of project without EMP is also assessed.
The exhaustive list of parameters selected for impact assessment by BEES methods is prepared along with PIU’s by numbers in parenthesis adjacent to parameters. The PIUs allocated amongst the selected environmental parameters for impact evaluation of the project, represent consensus in the opinion of experts of an interdisciplinary team. Depending on the type of projects the PIUs allocation and parameter selection differs widely.
However, a total of 1000 units in most cases allocated in the three to four major environmental categories viz., ecology, environmental pollution and human interests including socio-economics and aesthetics. The higher the number of PIUs, greater the relative importance (Table 24.4).
The impact scaling in this process has been accomplished through the use of value functional relationships of identified 45 typical parameters. Functional relationships refer to transforming parameter measurements (baseliner or predicted values) into subjective evaluations through graphical means.
Objective measurements are transformed into subjective interpretation of environmental quality (EQ) on a scale representing, a value of 1.0 for good quality and 0.0 for poor quality.