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ENVS402 – Environmental Impact Assessment
7. Environmental Impact pMitigating measures
I. Benefit enhancing measures (selection and implementation)
II. Adverse Impact mitigating measures (selection and
implementation)
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7. Environmental Impact Mitigating measuresp g g
The purpose of mitigation measures is to avoid, reduce or minimize unwanted impacts
and enhance beneficial
impactsimpacts and enhance beneficial impacts
Selection of alternatives is also a form
ofSelection of alternatives is also a form of mitigation in terms of impact, cost and technologygy
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Mitigation is. . .Definition of mitigation
g . . .
The implementation of measures designed to reduce thedesigned to
reduce the undesirable effects of a proposed action on the
environment
Mitigation is a key part of theMitigation is a key part of the
EIA process. It is essential to achieving environmentally
d d i!
Source: ENCAP EA-ESD Course: Mitigation &
Monitoring3
sound design.
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Different types of mitigation measures act in different ways to
reduce adverse impacts:
Type of measure How it works Examples
Fully or partially prevent an PREVENT contamination of
Prevention & Control measures
y p y pimpact/reduce a risk by:
Changing means or techniqueChanging the site
PREVENT contamination of wells, by SITING wells a minimum
distance from latrines.Implement health education
Changing the siteSpecifying operating practices
programInitiate public awareness prog.
Compensatory measures
Offset adverse impacts in one area with improvements
elsewhere
Plant trees in a new location to COMPENSATE for clearing a
construction site.
Remediation/Correctivemeasures
Repair or restore the environment after damage is done.
Re-grade and replant a borrow pit after construction is
finished
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measures
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Example of Mitigation:O ti ti t t & t l i tOperating
practices to prevent & control impacts
IrrigationPotential impact:salinization of soilssalinization of
soilsMitigation: avoid water-logging by using
d f improved on-farm water management, including placement of
drainage p gstructures.
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Example of Mitigation:Change of site to prevent & control
impactsChange of site to prevent & control impacts
l d Rural road constructionPotential impact: route traverses
nesting area for a traverses nesting area for a threatened species
of bird Mitigation:
d d Re-route road to avoid nesting site.Also, minimize
,construction noise and other disturbance during nesting season
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nesting season
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Reliability of mitigation measures: Reliability of mitigation
measures: site & technique changes vs. operating practices
PREVENTION of impacts by changes to site or technique ischanges
to site or technique is the most reliable approach to
mitigation.
CONTROL of impacts with operating practices is less reliable,
because the practices
!, p
must be continued after hand-over of the activity.
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Do I mitigate EVERY impact?
NOT NECESSARILYNOT NECESSARILY.Mitigation is directed at two
targets.
serious impacts1 easily mitigated impacts
2
First, the most serious impacts identified by
After addressing the most serious impacts,p y
the EIA process should ALWAYS be mitigated.
there may be small impacts for which mitigation is easy and
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mitigation is easy and low-cost.
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7. Environmental Impact Mitigating measuresp g g
A Framework of Impact Mitigation
DesirableAVOIDANCE Alt. Sites/Technology
MITIGATION Actions
COMPENSATION Use as last resort
Undesirable
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7. Environmental Impact Mitigating measuresp g g
Characteristics of Impact Mitigation Measures
Proposed mitigation measures should be able to describe;1
the impact it will avoid mitigate or compensate1.
the impact it will avoid, mitigate or compensate
when implemented,2.
an assessment of the effectiveness of
protection measures,3.
the next best alternative,4.
the cost of the protection measures,p ,5.
and the implementation plan for putting the
measure into practice.
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7. Environmental Impact Mitigating measuresp g g
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7. Environmental Impact Mitigating measuresp g g
Implementation of Mitigation Measures
Implementation of Mitigation Measures:•
should be cost effective and locally applicable and can be
proposed during different stages of project
implementationproposed during different stages of project implementation.
•
Pre‐construction (such as compensation for land acquisition),•
Construction (such as planning and designing activities)•
Construction (such as planning and designing activities),•
Operational stages (such as maintenance activities).
• The cost is usually about 10 % of the total cost of the
project•
The cost is usually about 10 % of the total cost of the project (although it depends on the nature, size, location etc. of the project)
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