The document discusses various methods used for predicting and evaluating environmental impacts in environmental impact assessments (EIAs). It describes two main categories of impact prediction methods: extrapolative methods based on past data and trends, and normative methods based on desired targets or standards. Specific methods mentioned include mathematical models, statistical models, GIS, experiments, and expert judgment. Key considerations for impact prediction are also outlined. Impact evaluation methods discussed are significance determination based on factors like public concern, effects on ecosystems, and standards, as well as analytical methods like cost-benefit analysis and multi-criteria scoring. The document concludes by linking impact prediction, evaluation, and the role of mitigation measures in EIAs.

2. 2
In EIA, the term “impacts” is used
instead of “effects of activities.”
Definition of EIA
Environmental Impact Assessment is…
A formal process for identifying:
•likely effects of activities or projects
on the ENVIRONMENT, and on
human health and welfare.
•means and measures to mitigate &
monitor these impacts
Environment is broadly
interpreted: physical,
biological, and
social.
“An assessment of the impact of a planned activity on the
environment”. UNECE (1991)

3. What to predict?
The object of prediction is to identify the magnitude and other dimensions of identified
change in the environment with a project or action, in comparison with the situation
without that project or action.
• How any project component may give rise to an impact
• Probability of impacts occurring
• Magnitude of each impact
• Spatial and temporal of each impact
What type of
change will happen?
Prediction
After projectBefore project Impact
Generated CumulativeIndirectDirect
Impact at
different
time
Impact at
different
scale

4. Important Considerations for Impact Prediction
1. Baseline condition (surrounding environment)
2. Uncertainty (anything can be happened)
3. Spatial limits ( place limitation)
4. Temporal boundaries (change of time)
5. Incremental condition

5. 1. EXTRAPOLATIVE METHODS
2. NORMATIVE METHODS
1. MATHEMATICAL MODEL
2. STATISTICAL MODELS
3. GEOGRAPHY INFORMATION SYSTEM
4. FIELD AND LABORATORY EXPERIMENTAL METHODS
5. PHYSICAL MODELS
6. EXPERT JUDGMENTS

6. Made on the basis of past and present data---
include trend and scenario analysis (the common sense
forecast of the future), analogies (transferring experience from
elsewhere), and intuitive forecasting from group
consensus (Delphi Method).
How the fulfillment of a desired target is achieved.
For example, if in one construction project, a target set is to employ
50% of the local populace. Meeting this target may require
changing the project and associated employment policy.

7. • based on cause-effect relationships
• usually expressed in the form of mathematical functions. (They may be
simple input-output models or of complex dynamic types.)
• Such models are primarily used for predicting the impact only partially
(e.g., model for phosphorus retention in a lake, or model to predict the
economic multiplier in a particular area).
1. DETERMINISTIC MODELS
2. STOCHASTIC MODEL

8. Statistical analysis are sometimes used to indicate the relationship
between the data and test hypothesis,
For example, in predicting flood frequencies.
Satellite images, physical maps and aerial photographs provide
information on existing resources.
Prediction of impacts of the development project can be made by
analyzing the effect of project activities on the resources present in
the location by using GIS techniques.
Field inventory carried out prior to project implementation provide the
baseline information of resources.
For example, a fish resource survey in the River of Nepal
indicated that a long-distance migratory fish species are existing in
the river. It could then be determined that the construction of a dam
in the upstream part of the river might create an obstruction for their
upstream migration of the fish for breeding.

9. These models are closely linked to field and laboratory experiments
making critical engineering and other decisions on site. Basically, a
model of an area likely to be impacted is constructed but on a smaller
scale.
For example, it could show the physical parameters of a Run-
of-river hydropower project. Both natural features such as topography
and socio-cultural features such as villages, schools and bridges are
included. In the case of rivers, the effect of impoundment on flow can
be calculated.
The experience of one place could very well be utilized for similar
places elsewhere where the environmental impacts are unknown
a) Produce acceptable results,
b) Be replicable,
c) Be consistent, and
d) Be adaptable.

10. Evaluation
The purpose of impact evaluation is to assign relative significance to
predicted impacts associated with the project, and to determine the
order in which impacts are to be avoided, mitigated or compensated.
• Impact assessment involves valuating the significance of the
impacts identified
• Significance can be determined through professional judgment,
reference to regulations etc.
• Potential for bias in determining what is significant
• The conclusions of the impact assessment can ultimately be used
by decision-makers when determining the fate of the project
application

11. • scientific and professional judgments;
• measure of disturbance to ecological systems;
• impacts on social values and quality of life;
• existence of environmental standards, that is, international, national,
provincial or local agreements;
The key elements for assessing the significance of impacts
include: level of public concern;

12. 1. Level of public concern;
2. Scientific and professional judgment;
3. Measure of disturbance to ecological systems;
4. Impacts on social values and quality of life;
How Is Impact Significance Determined?
Analytical Methods For Impact Evaluation:
Analytical methods seek to introduce a rational approach to
evaluation.
1. COST—BENEFIT ANALYSIS AND MONETARY VALUATION TECHNIQUES
2. SCORING AND WEIGHTING AND MULTI-CRITERIA METHODS

13. Cost-benefit analysis and monetary valuation techniques:
Cost-benefit analysis and monetary valuation techniques Cost-
benefit analysis itself lies in a range of project and plan appraisal
methods that seek to apply monetary values to costs and benefits
(Litchfield et al. 1975).
Example:
Cost Criteria WIND-FARM POWER GENERATOR COAL-FIRED POWER
GENERATORCentralized Generator Distributed Generator
Economic Cost
Initial Cost
site exploration ** *** ***
securing land access ** *** ***
wind turbines and components ** ***
installation cost ** **
foundation cost ** **
Total Initial Cost **** ***** ***
maintenance cost ** ** ***
replacement cost *** *** **
energy production cost ** ** *
transmission cost *** *** **
Total Operational-Maintenance Cost *** *** **
Average plant life 25 years 20 years 50 years
health damage of the society * * **
Environmental Cost
environmental damage * ** ***
emission trading scheme - - ***

14. Benefit Criteria
WIND-FARM POWER GENERATOR COAL-FIRED POWER
GENERATORCentralized
Generator Distributed Generator
Economic Benefit
reliability + + +++
security of supply +++ +++ ++
Social Benefit
employment opportunities + + +++
Environmental Cost
reduction of air pollution +++ +++ -
Benefit Analysis

15. Scoring And Weighting and Multi-criteria Methods:
Scoring may use quantitative or qualitative scales, according to
the availability of information on the impact under consideration.
How different levels of impact (in this example noise, whose
measurement is in units of Less 10dBA) can be scored in different
systems. These systems seek to standardize the impact scores for
purposes of comparison (Lee 1987).

16. The implementation of measures designed to reduce the
undesirable effects of a proposed action on the environment.
Mitigation aims to maximize positive impacts and (particularly)
minimize significant negative impacts.
Mitigation
Impacts remaining after mitigation are known as residual impacts

17. aim is the identification of likely adverse effects associated with
development, and their mitigation.
Mitigation In EIA Practice:
‘adverse effect’ can be defined as an effect
perceived by the developer or by
stakeholders to cause destruction to an
environmental parameter affected by the
development, either directly or indirectly

18. 1. The source of the effect (for instance, noise emitting
equipment, a toxicant, a tall structure);
2. The receptor (that is, the environmental entity likely to be
adversely affected); and
3. The pathway (the route by which a receptor could be exposed
to the effect)
4. Adverse effect can only occur when all three components are
simultaneously present in the
5. Surrounding environment, as is demonstrated.
Types of Mitigation In EIA :

19. The Mitigation Hierarchy:
Mitigation hierarchy
Avoid Reduce Remedy Compensate Enhance
Mitigation is the topic of an upcoming module!

20. Dimension/phase of Mitigation:
1. The phase of the project or timing when mitigations applied —
its ‘implementation phase’; and
2. ‘How to do it’ or the means by which the action envisaged is
to be enacted — the ‘methodology’.

21. Fig: Linkage between prediction, Evaluation and
Mitigation
• Impact prediction and the evaluation of the significance of impacts often
constitute a "black box” in EIA studies.
• Various Impact prediction, evaluation and mitigation are available to the
analyst, and these can help to underpin analysis.
• Mitigation measures come into play particularly at this stage. However,
the increasing sophistication of some methods does run the risk of cutting
out key actors, and especially the public, from the EIA process.
Summary

22. Thank You ALL…