Module 3

E I A ME T H OD OL O G I ES : AD H O C , CH E C KL I ST ,
MA TRIX , NE TWO RK A ND ASS ESS MEN T O F
E CO L O G IC A L I M P AC T S AN D SO CI O E CO NO M I C
IMPACTS.
 Socioeconomic impacts

 Socio-economic impacts are the influence of projects and/or

programmes or policies on the human values, culture, living
standard.
 Institutions undertaking large investment projects such as
highways, air ports, sewerage systems, water resources projects
(reservoirs, water relating systems, diversions, canals) stimulates
secondary impacts in the form of associated investments and
changes in socio-economic activities.
 These effects include changes in the existing community
facilities and activities, induce new facilities in the next round
and changes in natural conditions. All such effects may be
substantial than the primary impacts of the original actions.
 SOCIO-ECONOMIC IMPACT ASSESSMENT
METHODOLOGY

 Step 1. Identification of potential socio-economic

impacts for assessment.
 This is to identify the basic indicators to assess the
environmental impacts of all kinds (air pollution, water
pollution, noise pollution) which will effect human quality
of life Other important factors will be
 demographic factors – population, density, literacy
 economic variables – land use patterns, income levels, price
levels, employment/unemployment level, commercial
activities
 social variables – patterns of life and work, ethnic
composition, religious and tribal factors, public utilities
 project specific variables – displacement, business,
recruitment of manpower, project technology
 Step 2. Description of existing socio-economic or
human environment of the project area Developing a social
profile based on siting of projects

 Step 3. Procurement of relevant standards, criteria and

guidelines
There are direct effects of pollutants/emissions on the public and
whenever people are affected, health and welfare socio economic
considerations become important
 Step 4. Prediction of Socio-economic Impacts
 Prediction of Socio-economic Impacts with or without the project is an
important technical exercise. There is no unique method for
predicting the impacts yet four approaches are indicated:

➢ qualitative description
➢ quantitative description
➢ application specific prediction technique (may involve survey from
secondary sources or qualitative descriptive approach like Delphi
method or Historical analogies
➢ comparison of the effects of alternatives
 Step 5. Assessment of Socio-economic Impact
 Assessment of socio-economic impacts with or without project in its surrounding
areas is difficult as there are no established standards for these. Some impacts
may be clearly visible and assessable such as:
➢ generation of employment for local people (+ve impact)
➢ increase in earnings of people (+ve impact)
➢ pressure on local services (-ve impact)
➢ increase in business and trade (+ve impact)
➢ increase in crime rate in the region (-ve impact)
➢ interaction with outside people (+ve impact)
➢ opening of attitudes of people (+ve impact)
 Step 6. Mitigation Measures
 Though there is very little in the form of mitigation measure to
reduce the adverse socio-economic impacts of the project.
 However, Some local benefits, particularly employment of the
local people, rehabilitation and resettlement of project affected
people will be mandatory by law.
 The project is a user of local resources and in lieu it has to give
back some benefits to the local population otherwise they resent
its activities and the project functioning is jeopardized.
 Mitigation measures will include, providing housing schools,
colleges, hospital, power and other social services.
 IMPACT ASSESSMENT METHODOLOGY

 Choice of a Methodology

➢ Use: Whether the document is for information or a decision document The decision
document requires more details and greater emphasis is on key issues, quantification and
comparison of alternatives.

➢ Alternatives: Much would depend on what alternatives to the project are available since
these would require a more thorough quantification and comparison.

➢ Public involvement: The role of stake holders and their participation may also require
issues which are relevant and need discussion and thus details.

➢ Resources: What resources are available for the document preparation in terms of
experts available, data, time and money.
 Familiarity: Familiarity with ground conditions will also be
a keen element. Greater familiarity will improve the validity
of subjective significance.
 Issue significance: If the issues involved are larger then
more details are needed, quantification is important and
hence the choice
 Administrative: Are the documents being prepared are
dictated by procedure of implementing agency
 1.AD HOC method

 Simple method based on subjective assessment of

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.
 Types of Ad hoc method

 Opinion polls.
 Experts opinion.
 Delphi methods (The Delphi method is a forecasting process
framework based on the results of several rounds of
questionnaires sent to a panel of experts. Several rounds of
questionnaires are sent out, and the anonymous responses are
aggregated and shared with the group after each round. The
experts are allowed to adjust their answers in subsequent
rounds. Since multiple rounds of questions are asked and the
panel is told what the group thinks as a whole, the Delphi
method seeks to reach the correct response through consensus)
 Advantages
 Specialists on a particular area will provide guidance.
 Disadvantage
 It requires expert.
 Short/long term impact are merely examined on guess
basis.
 Identification, prediction and interpretation of impacts are
quite poor
THE CHECKLIST METHOD
CHECK + LIST =
CHECKLIST

+ =
 Checklist Method

 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.
 Environmental Impact Assessment
Checklist is a list of items that has to be
checked or done to anticipate the
environmental consequences of a
development before planning permission is
granted. Environmental Impact
Assessment Checklist are designed to
establish whether a proposed project is
likely to have negative impacts on the
environment
 There are 4 types of Checklist : simple
checklist, weighted-scale checklist, forced
choice checklist and descriptive checklist.
Checklist method - Example
 Simple check list

 It includes certain statements of yes or no type.

In simple checklist method, equal

importance or weightage is given to all
the statement.
 Simple Lists.
➢ Presents a list of parameters related to the project
➢ No guidelines on how to interpret and measure the parameter
➢ Does not help in decision making
➢ No information on cause effect relationship
➢ Strong in impact identification
➢ No information needed on magnitude or importance of impacts"
➢ List of parameters without guidelines provided on how to
interpret and measure an environmental parameter.
 Weighted scale checklist

 Weights are assigned to different statements to

indicate their importance.
FORCED CHOICE CHECKLIST
In this method, the raters are given a set
of multiple choice (forced choice)
questions, from which they are to select
one option and rate the statement.
This list contains only positive or
negative sets of readymade choices of
behaviors to choose from.
 Descriptive checklists

 Descriptive checklists include list of environmental factors along with

information on measurement, impact prediction and assessment.

• This provides more information on nature and magnitude of

impacts rather than just identifying whether they would occur or not.

• The information within each box can be quantitative or qualitative.

• The identification of the incidence of cumulative impacts is again

essentially reliant upon expert opinion.

Descriptive checklist
 Descriptive checklists

• Checklists are very descriptive and focus on details about methodology

• Generally used by decision makers during project appraisal.
• Simply identify the possible potential impacts without any rating regarding
their relative magnitudes
 Questionnaire Checklist

• Checklist prepared based on the questions asked.

• This is used mainly for Public Consultation; it tells about the

stakeholders awareness and responses towards the proposed project.

• The questionnaire is then further evaluated in spread sheets to find

the scale of impacts and weight of parameters based on public

opinion.
Questionnaire check list
ADVANTAGES OF CHECKLIST
Encourages discussion during the
initial stages of assessment.
Helps to ensure that the vital impacts
are not neglected.
Checklists may also help to produce
a higher degree of awareness of the
environmental aspects of a project.

Quantification of impacts is possible

using the weighted-scale method.
 DISADVANTAGES

 Do not distinguish between direct and indirect impacts.

 They are too general or incomplete
 Lack of detailed information because of ready made options
 Time consuming and trained people are required.
 The identification of effects is qualitative and subjective.
 The main drawback of the checklist method is the inability to
relate individual activities to environmental components
affected by these activities
 Matrix Method

 Matrix are two-dimensional tables which facilitate the

identification of impacts arising from the interaction between
project activities and specific environmental components.
Identifies interaction between Project actions- Environmental
Parameter
 Gives information on cause effect relationship
 Environmental items (Y axis) and Project actions (X axis)
 The relationship between Action & Env. Parameter will be given
at the intersection
 TYPES OF MATRIX

1 Simple Matrix Weighted Matrix

5

Time Quantified Matrix

dependent (Leopold Matrix)
2 matrix 4

Magnitude
Matrix
3
 SIMPLE MATRIX
2-dimensional in nature.
It is formed where project actions are listed along
horizontal axis and their environmental impacts in the
vertical axis.
A simple “x” is given to those pairs that have an interaction
between themselves.
TIME DEPENDENT MATRIX
2-dimensional matrix.
Include a number sequence to represent the
time scale (eg.one figure per year) of the
impacts.
 MAGNITUDE MATRIX
Go beyond the mere identification of impact
according to their magnitude, importance
and or time frame(eg short, medium, long
term)
The magnitude of the impact is denoted in
the matrix by putting symbols.
 QUANTIFIED MATRIX
The best known type of quantified matrix is the
Leopold Matrix, which was developed for the US
geological survey by Leopold et al in 1971.
This matrix is based on a horizontal list of 100
project action and a vertical list of 88
environmental components.
HOW TO USE LEOPOLD MATRIX
Identify All actions that are part of the proposed project.
Under each of the proposed actions, place a slash
at inter section with each item in the side of the
matrix if an impact is possible.
 HOW TO USE LEOPOLD MATRIX
In the upper left hand corner of each box with a slash,
place a number from 1 to 10 which indicate the
Magnitude of the possible impact; 10 represents- the
greatest magnitude of impact and 1, the least (no
zeroes). Before each number place + (if the impact
would be beneficial).

In the lower right hand corner of the box place a

number 1 to 10 which indicates the importance of the
possible impact (e.g regional vs local); 10 represents the
greatest importance and 1 the least (non zeroes).
HOW TO USE LEOPOLD
MATRIX
 LEOPOLD MATRIX
The leopold matrix is easily understood, can be
applied to a wide range of developments, and is
reasonably comprehensive for first order, direct
impact.
LIMITATIONS OF LEOPOLD MATRIX
It can’t reveal indirect effects of development.
The inclusion of magnitude/significance scores
has additional drawbacks: It gives no indication
on whether these values are based are qualitative
or quantitative.
It doesn’t specify the probability of impact occurring.
 Advantages

 It presents an easily understood summary of a large number of

primary impacts.
 It is a generalized but well defined approach, forcing a
comprehensive consideration of environmental components and
primary impacts.
 It is an easily performed process which can specify the overall
character of a project early in the design phase.
 In an extended form, the method can include information about
many impact attributes, and clarify the assumptions supporting
the assessments.
 Matrices have low resource requirements.
 WEIGHTED MATRIX
Weighted matrices were developed in an
attempt to respond to some of the above
problems.
Importance weightings are assigned to
environmental components, and sometimes
to project components.
The impact of the project (component) on
the environmental component then
assessed by multiplying the appropriate
weightings with magnitude of impact.
WEIGHTED MATRIX
 OVERLAY METHOD
The overlay approach to impact assessment
involves the use of a series of transparencies to
identify, predict, assign relative significance to, and
communicate impacts in a geographical reference
frame larger in scale than a localized action would
require.

The overlay approach can accommodate both

qualitative and quantitative data.
 OVERLAY METHOD

It enables separate mapping of critical

environmental features at the same scale as project's
site plan (Ex: wetlands, steep slopes, soils,
floodplains, bedrock outcrops, wildlife habitats,
vegetative communities, cultural resources, etc).
APPLICATIONS OF OVERLAY METHOD
The approach has
been employed for
selecting highway
corridors.
For evaluating
development options
in coastal areas.
Used to map impacts
spatially and display
them editorially.
 McHARG OVERLAY
The original overlay technique, the McHarg overlay
is based on a set of transparent maps, each of which
represents the spatial variation of an environmental
parameter (e.g., susceptibility to erosion or
recreational value).

The maps are shaded to show three degrees of

parameter compatibility with the proposed
project.
 McHARG OVERLAY

A composite picture of the overall social cost of

affecting any particular area is approximated by
superimposing all the transparent maps.
 McHARG OVERLAY
Any number of project alternatives can be located
on the final map to investigate the degree of
associated impacts.

The validity of the analysis is related to the type

and number of parameters chosen.

For a readable composite map, the number of

parameters in a transparency overlay is limited
to about 10 (Munn, 1979).
 McHARG OVERLAY

Parameter maps present data in a summarized

and easily interpreted form but are unable to
reflect the possibility of secondary impacts. They
also rely heavily on cartographic skills and their
effectiveness depends to a large degree on
cartographic execution.
 MODERN TECHNIQUE
Modern technique of the same activity is done
using computer software, hardware, data and
skilled people. It is called GIS (Geographic
Information Systems).

The old method is easily adaptable for use with

a computer, programmed to perform the tasks
of aggregating the predicted impacts for each
geographical subdivision and of searching for
the areas least affected.
 MODERN TECHNIQUE

Automated procedures are also available for

selecting sequences of unit areas for routing
highways, pipelines, and other corridors.

The computer method is more flexible, and

has an advantage whenever the reviewer
suggests that the system of weights be
changed.
ADVANTAGES OF OVERLAY
METHOD
It is easy to understand and use.

It has a good display .

It is good for setting site selection.

DISADVANTAGES OF OVERLAY METHOD
It addresses only direct impacts.
The burden of ensuring comprehensiveness is largely
on the analyst
It does not address impact duration or probability
The approach is selective because there is a limit to
the number of transparencies that can be viewed
together.
Extreme impacts with small probabilities of
occurrence are not considered. However, a skilled
assessor may make indications in a footnote or on a
supplementary map.
 Network Method
4

•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

 Advantages
•Presentation matrices can only clearly show the primary
or first-order impacts within any particular activity-
component framework. It is possible, however, to
investigate higher order linkages in two dimensions by
using networks.

• It is possible to translate networks into mathematical

models for a more quantitative judgement. The network
method structures the relationships implied in qualitative
simulations.
 Disadvantages:
• One of the main limitations of the network method is
that since impacts are not scored in any quantitative
way, the comparison of project alternatives is not
readily achieved.

• Spatial representation of impacts is not possible.