EIA Methods Flashcards
(18 cards)
Different aims require different methods . What methods would use for :
Scoping and identification.
Predicting and evaluating.
For scoping and identifying: you can use matrices , expert opinions, spatial and network analysis and checklists.
For predicting and evaluating you can use expert opinion , matrices, modelling nd the environmental evaluation index
True or false : several methods can be used in one step , one method can be used in different steps .
True
What are some key consider when selecting methods for and EIA
Methods selected depend on
Specific project , system or development
The VECs
The information need to be compiled and compared
Resources need (expertise,finances,time, is pre project data available).
What step or aim in the process (different steps require different methods)
Boundaries (spatial and temporal)
Methodology:expert judgement
Relies on the knowledge and experience of experts to predict and identify environmental impacts . Usually experts use understanding gained from similar projects to make these predictions.
Methodology: checklists
Systematic approach to identifying environmental impacts.
Two main types :
Questionnaire checklist: a set of questions designed to prompt consideration of various environmental aspects.
Threshold checklist: identifies potential impacts and also incorporate criteria for determine the significance of the impact . Uses threshold of concern (TOC), which is then compared to other alternatives
What are the pros and cons of expert judgement.
Pro: time efficient
Con very subjective and has a lot of uncertainty
What are the pros and cons of checklists.
Pros:
Structured approach
Facilitate comparison with other alternatives
Time efficient
Cons:
May not capture adequately the complex interactions between different environmental components.
Uncertainties
Maybe subjective and may not be tailored to specific projects
Methodology: matrices
There are four types of matrices :
Simple matrix.
Matrix with development over time.
Matrix with information about magnitude and significance-Leopold
Matrix with weighted information - Peterson
How can you define impact magnitude?
Magnitude is defined as the intensity or severity of and environmental impact.
-10(very negative ) to 10(very positive), 0 no impact.
This is determine based one :
Concentration of pollutants
Duration of impact
Area of influence
How can you define impact significance?
This refers to relevance r importance of an environmental impact. 0 to 10.
Dependent on :
Sensitivity of the area : is it an endangered or rare ecosystem impacts here more significant than on a resilient ecosystem.
Population density: impact in a densely populated area will be more significant that impacts on a sparsely populated one .
Endangered species : impacts on endangered species much more significant due to conservation status.
Protected areas: impacts in such areas much more significant dues cultural values .
Water supply areas
Breeding sites
What are the pros and cons of matrices ?
Pros: good visual over view
Links inputs to actions
Cons
As projects become larger there the risk of it becoming to complex and difficult to understand.
Risk of double counting impacts ( sometimes due to the structure of the matrix).
Simpler matrices may sometimes not capture indirect effects ,or effects that goes beyond the obvious impact of the project .
While numbers may give the impression of objectivity the selection of these numbers is often very subjective.
Methodology : Environmental Evaluation Index.
This a method that quantifies the environmental impacts of a projects making comparison with alternatives easy. Usually used with projects that have impacts on multiple environmental components.
A negative value = loss of environmental quality.
What are the pros an cons of the Environmental Index Unit ?
Pros : quantifies impacts making it easy to compare .
Allows for the combination of different parameters into a single index.
Cons: hidden subjectivity
Tendency to oversimplify complex environmental interactions.
A seemingly positive or neutral index may mask the significant negative effects on an individual environmental component if they are offset by positive effect on others.
Methodology: networks
Network: Network or system diagram : visual representation of interconnected elements showing how changes in one element can affect other elements.
Types: flow chart , concept diagrams , influence diagrams ( demonstrate cause and effect relationship )
Methodology: models
Modeled : these a simplified versions of real world systems.
Types :
COnceptual: uses flow diagrams to represent key components of a system.
Statistical models : use statistical relationships between variables to predict outcomes.
Dynamic model: incorporates time as variable allowing for simulations of how a system changes over time in response to various inputs and disturbances.
What are the pros and cons for modeling
Pros : useful for predictions especially when measurement is not an option.
Allows Dp for simulation of multiple mitigation alternatives leading to a more effective decision making process,
Cons :
Resource intensive : expertise , time and data
The accuracy and reliability of the model is highly dependent quality of inputted data .
True or false : GIS is another methodology for EIA?
True
Methodology: multi-criteria analysis (MCA)
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