Lecture 4 Flashcards
1
Q
EIA Methodologies
A
- Methodology / structural approaches for doing one or more activities of EIA.
- There are some specific characteristic which an EIA methodology should depict.
✔ It should be appropriate to the necessary task of EIA process such as impact
identification/comparison of alternatives.
✔ It should be significantly free from assessors bias
✔ It should be economical in terms of costs, and its requirement of data, investigating time,
personnel, equipment and facilities.
✔ This stage of EIA identifies and predicts the** likely Environmental and social impact** of the
proposed project and focuses on
1. Impact Identification
2. Impact Prediction
3. Impact Evaluation
2
Q
Impact identification
A
- Impact Identification attempts to answer the question, “what will happen when a project
enters its operational stage?” - A List of important impacts such as changes in ambient air quality, changes in water and soil qualities, noise levels, wildlife habitats, species diversity, social and cultural systems, employment levels etc may be prepared.
- The important sources of impact like smoke emission, consumption of water, discharge of
effluents etc are identified.
Methods include - Ad hoc method
- Checklists
- Matrices
- Networks
- Overlays
3
Q
Ad hoc methods
A
- Simple method based on **subjective environment impacts **on broad aspects.
- Ad hoc method is useful when **time constraints and lack of information **require that the EIA
must rely exclusively on expert opinion. - It provides **minimal guidance for total impact assessment **while suggesting the broad areas
of possible impacts and the general nature of these possible impacts. - When more scientific methods are available, it is not recommended.
4
Q
Types of Adhoc method
A
Opinion polls.
Experts opinion.
Delphi methods etc
5
Q
Advantage of Adhoc method
A
Guidance from Specialists on a particular area .
6
Q
Disadvantages of Adhoc method
A
✔ It require expert.
✔ Short/long term impact are examined merely on guess basis.
✔Poor Identification , prediction and interpretation of impacts
7
Q
Checklist methods
A
- Checklist means a listing of potential Environmental Impacts.
- This method is done to assess the nature of the impacts i.e. its type such as adverse
/beneficial , short term or long term , no effect or significant impact, reversible or irreversible
etc
8
Q
Types of checklist method
A
- Simple Lists.
- Descriptive Checklists.
- Scaling Checklists.
- Questionnaire Checklists
9
Q
Advantages of checklist method
A
✔ Simple to understand and use.
✔ Good for site selection and priority setting.
10
Q
Disadvantages of checklist method
A
✔ Do not distinguish between direct and indirect impacts.
✔ Do not link action and impact.
✔ Sometime it is a cumbersome task
11
Q
Matrices
A
- Matrix and its variants provide us a framework of interaction of different actions /activities of
a project with potential EI caused by them. - A simple interaction matrix is formed where project actions are listed along one axis i.e.
vertically and **EI **are listed along the other side i.e. horizontally. - It was pioneer by Leopold et al(1971).
- It lists about 100 project actions and about 88 environmental characteristic and condition.
11
Q
Advantages of matrix method
A
✔ Link action to impact
✔Good method for displaying EIA results
12
Q
Disadvantages of matrix method
A
✔ Difficult to **distinguish **direct and indirect impacts
✔ Significant potential for double-counting of impacts
✔Qualitative
13
Q
Networks method
A
- It uses the **matrix **approach by extending it take into account primary as well the secondary
impacts. - Shown in the form of tree called as **Relevance/Impact tree/Sequence diagram. **
- Identification of direct, indirect /short and long term environment impact is a crucial and intact basic step of making Impact tree.
- Used to identify cause-effect linkages
- Visual description of linkages
14
Q
Advantages of Network method
A
✔Link action to impact
✔Useful in simplified form in checking for second order impacts
✔Handles direct and indirect impacts
15
Q
Disadvantages of Network method
A
✔Can become overly complex if used beyond simplified version
✔Qualitative
16
Q
Overlay method
A
- Rely on a set of maps of a project area’s environmental characteristics covering physical,
social, ecological, aesthetic aspects. - **Separate mapping **of critical environmental features at the same scale as project’s site plan
e.g. wetlands, steep slopes, soils, floodplains, bedrock outcrops, wildlife habitats, vegetative
communities, and cultural resources… - Older Technique: environmental features are mapped on transparent plastic in different colors.
- Newer Technique: **Geographic Information Systems **(GIS).
17
Q
Advantages of Overlay method
A
✔ Easy to understand and use
✔Good display method
✔Good for site selection setting
18
Q
Disadvantages of overlay method
A
✔ Address only direct impacts
✔ Do not address impact duration or probability
19
Q
Impact prediction
A
- The accumulated knowledge of the findings of the environmental investigations form the
basis for the prediction of impacts. - The objective 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.
Points to be consider for impact prediction.
1. **Baseline condition **
2. **Uncertainty **
3. Spatial limits
4. **Temporary boundaries **
5. **Incremental condition **
6. Quantitative and Qualitative methods
20
Q
Characteristics of environmental impacts
A
- nature (positive, negative, direct, indirect, cumulative);
- magnitude (severe, moderate, low);
- extent/location (area/volume covered, distribution);
- timing (during construction, operation, decommissioning, immediate, delayed, rate of
change); - duration (short term, long term, intermittent, continuous);
- reversibility/irreversibility;
- likelihood (probability, uncertainty or confidence in the prediction);
- significance (local, regional, global).
21
Q
Baseline
A
- An impact or effect can be described as the change in an environmental parameter,
which results from a particular activity or
intervention. - The change is the difference between the
environmental parameter with the project
compared to that without the project. - It is predicted or measured over a specified period and within a defined area
22
Q
Methods of prediction
A
- Extrapolative Methods
- Normative Methods
Other Prediction Methods - Mathematical Model
- Statistical Models
- Geography Information System
- Field And Laboratory Experimental Methods
- Physical Models
- Expert Judgment
23
Q
Extrapolative methods
A
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).
24
Normative methods
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
25
Mathematical model
* 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).
* DETERMINISTIC MODEL
* STOCHASTIC MODEL
26
Statistical models
Statistical analysis are sometimes used to **indicate** the relationship between the **data and test hypothesis**, For example, in predicting flood frequencies.
27
GIS methods
* **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.
28
Field and laboratory methods
* 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
29
Physical model
* 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.
30
Expert judgement
The **experience** of one place could very well be utilized for similar places elsewhere for evaluating unknown environmental impacts a) Produce acceptable results, b) Be replicable, c)
Be consistent, and d) Be adaptable.
31
Evaluation of impact significance
* A **systematic process** should be followed in evaluating significance, distinguishing between ‘as **predicted**’ and ‘**residual**’ impacts.
* Step one involves evaluating the **significance of ‘as predicted’** impacts to define the requirements for mitigation and other remedial actions.
* Step two involves evaluating the significance of the ‘**residual’** impacts, i.e. after mitigation
measures are taken into account.
* This test is the critical measure of whether or not a proposal is likely to cause significant impacts.
* It is determined by the **joint consideration of its characteristics** (magnitude, extent, duration
etc.) and the importance (or value) that is attached to the resource losses, environmental
deterioration or alternative uses which are foregone
32
Criteria for impact evaluation
* Impact evaluation is a difficult and **contestable exercise**, between ‘facts’ and values and between EIA and decision-making.
* a **technical judgement** must be made of the extent to which mitigation will reduce ‘as
predicted’ impacts. Second, a **subjective value** must be placed on the significance of
residual impacts, using criteria and tests.
* Often specified criteria are environmental standards and thresholds, protected and sensitive
areas, valued ecological functions and components and resource and land use capabilities.
✔ emissions based, comprising standards for air and water quality, noise etc.
✔ environmental quality based, comprising significance criteria for valued ecosystem
components or similar attributes.
* The environmental acceptability of a proposal and the terms and conditions to be attached
to its implementation must be weighed against other economic and social factors by the
decision-maker
33
Criteria for impact evaluation
Part 2
* **Emissions based** standards will be jurisdiction specific (although certain standards may be
internationally recognised) and provide an objective, technical means of determining significance.
* The anticipated residual impacts either do or do not exceed the relevant standard.
* In many cases, an appropriate technical standard will not be available for the evaluation of significance
(e.g. ecological, social and visual impacts).
* **Environmental quality based** criteria or thresholds are qualitative, broadly drawn and require
interpretation.
* Impact evaluation is a subjective exercise, linking scientific criteria to social preferences and relating
them to the environment and community affected.
* When applying them, the criteria should be modified to take account of local value systems and
traditional practices.
* some countries and international agencies have established environmental sustainability criteria and
environmental acceptability rules
34
Aids and principles for evaluating significance
* environmental standards, guidelines and objectives;
* level of public concern (particularly over health and safety);
* scientific and professional evidence for:
* loss/disruption of valued resource stocks and ecological functions;
* negative impact on social values, quality of life and livelihood; and
* foreclosure of land and resource use opportunities
35
Probability and Acceptance of Risk
* Risk-based principles may be used to establish ‘rules of thumb’ for the acceptability of
effects.
* statistical threshold of significance may be established to define an acceptable incidence of
disease per million people exposed to a specified hazard (e.g. carcinogenic chemical).
* This approach is often controversial. It is important to document why and how the level and
acceptability of risk has been determined.
* A risk-based approach can be useful to address the significance of cumulative effects and
ecosystem level changes.
* Quantitative risk assessment will not be possible because of lack of knowledge of the
variability of natural systems.
* Qualitative rules of thumb may be set for cumulative loss or change.
* limiting drainage of wetlands to no more than 25 per cent of the area
36
Guiding principles for determining significance include
* use procedure and guidance established by the jurisdiction;
* adapt other relevant criteria or identify points of reference from comparable cases;
* assign significance in a rational, defensible way;
* be consistent in the comparison of alternatives; and
* document the reasons for the judgements made.
A test of significance can be applied by asking three questions:
✔ Are there residual environmental impacts?
✔ If yes, are these likely to be significant or not?
✔ If yes, are these significant effects likely to occur e.g. is the probability high, moderate or
low?
