1. Environmental Impact Assessment (EIA)

2. EIA: Introduction Introduction
Developmental activities like project implementation have economic, social and natural environment impacts in areas they are being implemented.
In order to predict environmental impacts of any development activity, to provide an opportunity to mitigate against negative impacts and to enhance positive impacts, the Environmental Impact Assessment (EIA) procedure was developed in the USA in the early 1970s.
The need to avoid adverse impacts and to ensure long term benefits led to the concept of sustainability.
EIA is one tool that can be used to ensure that developmental activities are in line with this concept of sustainable development .
 Definition
An EIA is a formal process for predicting environmental consequences of human development activities and for planning appropriate measures to eliminate or reduce adverse effects and augment positive effects (FAO, 1995).
An EIA is therefore a management tool for planners and decision-makers that complement the other engineering and economic considerations.
The purpose of an EIA is to present the consequences of different choices of actions and to make recommendations to a decision maker.

3. Aims and Objectives of EIA
There are different aims of EIA that will influence the choice of method and the scope of the study. The aim is dependent on who is the user as well as on the use of the result.
The aim of EIA according to Morgan (1998) is to; Anticipate important possible effects of proposed activities on the natural system (water, soil, air, biological system, and human health), anthropogenic systems (settlements and infrastructure), social and economic systems (work, education, recreation, health services) and cultural systems (beliefs, art, literature)
The process is formally sanctioned by a legislative or bureaucratic framework set within a national and local policy context.
These policies influence the character and direction of the EIA process in a given country and a given setting.

4. Roles and Perspectives in EIA
May vary since there are many persons of different categories involved in an EIA in various ways.
The following list is hypothetical, but may be used to illustrate what an EIA may mean to different categories (after Morgan 1998):
• Environmental scientist - a process that predicts a likely change in the environment (eg fish population, air quality etc)
• Sociologist - a process of informing local communities about changes in the environment allowing the population to participate in the decision-making
•Member of the local community - a way for the council and developers to justify a development project
Consultant - a job
Political scientist - a process that forces bureaucracies to recognise and respond to concerns about environmental change

5. Roles and Perspectives in EIA Cont.
Politician - a process that demonstrates that decision-making recognises environmental issues
•Developer - a process which allows the local authorities to employ more people
"Deep" ecologist - a process that allows the government and developers to maintain long term policy of resource development and growth without concern for the environment
Planner - a practical process for balancing the needs of development with the need to maintain important environmental and social characteristics of a locality
•Economist - a process for identifying externalities associated with a proposal and assign them monetary values
The information generated by the EIA process is used by the various groups and individuals, for formal and informal purposes and while formal purposes may dominate in terms of legal requirements, the informal purposes may well have important societal roles.
There may be many more perspectives than the mentioned, but they illustrate one problem that easily arises in the process of an EIA - the different perspectives can make it difficult to find a solution that all parties agree upon.

6. The composition of an EIA Team
This depends on the type of project to be implemented.
An EIA team for an irrigation and drainage project is likely to be composed of some or all of the following: a team leader; a hydrologist; an irrigation / drainage engineer; a fisheries biologist/ecologist; an agronomist/pesticide expert; a soil conservation expert; a biological/environmental scientist; an economist, a social scientist and a health scientist (preferably a epidemiologist).
The final structure of the team will vary depending on the project. Specialists may also be required for fieldwork, laboratory testing, library research, data processing, surveys and modelling.
The team leader will require significant management skill to coordinate the work of a team with diverse skills and knowledge.
There will be a large number of people involved in EIA apart from the full-time team members.
These people will be based in a wide range of organizations, such as the project proposing and authorizing bodies, regulatory authorities and various interest groups.
Such personnel would be located in various agencies and also in the private sector; a considerable number will need specific EIA training.

7. Advantages and benefits of EIA.
• Lower project costs in the long-term (fewer costly changes or add-ons at advanced stages of the project; lower probability of environmental disasters, court cases and/or costly clean-ups);
• Increased project acceptance by the public and key stakeholders;
• Improved project design/siting;
• More informed decision-making;
• More environmentally sensitive decisions;
• Increased accountability and transparency during the development process;
• Improved integration of projects into their environmental and social setting;
• Reduced environmental damage (mitigation measures planned and implemented in time to minimize adverse impacts on the environment).

8. Principles and Methodology of EIA
A suggested sequence of EIA steps is illustrated in Figure 2, where the arrows indicate possible iterations.
There is no standardised methodology of EIA.
The EIA process may be described as a number of steps, the contents of which are dependent on the purpose and nature of the study.
There is a large component of iteration in the process.
It is important that an EIA is carried out early in a development project, e.g. at a stage before the detailed design in a technical project see figure 1.
According to E7, (1997), EIA must begin as soon as a project is conceived, before irrevocable decisions are made.

9. FIGURE 1: EIA In the Project Life Cycle Source: E7, 1997.

10. Figure 2: The EIA process adapted from Morgan 1998.
Implementation
Needs/Justification
Figure 2: The EIA process adapted from Morgan 1998.

11. Summary of the EIA process
Need/justification
• What is the problem?
• What options/alternatives are available to solve the problem?
• What are the environmental implications of these options/ alternatives?
• What is the preferred option/ alternative? Why?
Screening
• Is a full EIA required?
Scoping
• What should the EIA include?
Impact identification and Prediction
• What are the environmental effects associated with proceeding with this project and its alternatives?
Impact Assessment
• What is the significance and/or importance of the effects?
• Which of the project alternatives is the preferred alternative?
Impact Mitigation
• Are there mitigation measures that could reduce the overall effects of the project and its alternatives?
Review and Decision-making
• Do the benefits of the proposed project outweigh the potential residual environmental effects?
Implementation
• How can the project best be implemented?
Monitoring
• ensure environmental regulations are being adhered to in project implementation,
• compare actual and predicted impacts
• Were there any unanticipated effects?
Evaluate performance /effectiveness of mitigation
Auditing
Analysis o f technical, procedural, and decision making aspects of the EIA process, draw lessons
Summary of the EIA process

12. Screening The process to decide whether an EIA is required or not.
Performed in order to ensure that proposals that will have a significant impact on the environment will undergo an EIA.
The process is governed by national legislation.
In some countries there is a list of projects where EIA is required.
Examples of projects that require EIA in Zimbabwe are;
Dams and lakes,
Drainage and Irrigation
Drainage of wetland or wildlife habitat,
Forestry
Conversion of forestry land to other use,
Housing Developments
Industry e.g. Chemical plants, Iron and steel smelting, cement plants, mining and quarrying plants, oil refineries, tourists resorts and recreational developments,
Infrastructure e.g. Highways, airports, railway lines, major pipelines, Thermal and hydro power plants, High voltage transmission lines, waste treatment and disposal facilities. 

13. Screening cont.
Project screening can be done in a number of different ways including: • measuring against simple criteria such as size, location or cost; • comparing the proposal with lists of project types that rarely need an EIA in other jurisdictions (e.g. minor transmission line) or that always need extensive study (e.g. major new power generation); • use lists of resources (e.g. rain forests), environmental problems (e.g. soil erosion, deforestation) and/or areas of special importance or sensitivity (e.g. national parks) so that any activity that affects such areas of concern will be judged to have significant environmental effects and require an EIA; • estimating the general impacts of a proposed project and comparing these against set thresholds; • doing a detailed, informal analysis using readily available data. Here tools like checklists or matrices (these are discussed in detail later in the text)

14. Scoping The process of deciding what should be included in an EIA.
It may be seen as a means for identifying the main public concern about a proposal and for organising the scientific work for the assessment.
The objectives of scoping are:
• to identify project stakeholders;
• to identify existing information sources and local knowledge;
• to inform stakeholders of the EIA and its objectives and get input on the EIA;
• to identify the key environmental concerns (community and scientific) related to a project and the relative importance of issues;
• to define the EIA work program, including a plan for public and stakeholder involvement;
• to define the range of project alternatives to be considered;
• to obtain agreement on the methods and techniques used in EIA studies and document preparation;
• to determine the spatial and temporal boundaries for the EIA studies. 
Scoping helps to centre EIA efforts on the collection and analysis of pertinent data and the assessment of significant environmental attributes.
The end result will be a work program which is well focused and cost-effective.
Failure to obtain government and public input at the scoping stage may result in later criticism of impact predictions and possible project delays.

15. Scoping cont. Possible methods for scoping include:
• Examination of EIAs for similar types of projects in similar environments;
• EIA methods such as checklists, matrices, networks, overlays, evaluation techniques and adaptive methods (hypotheses of effects);
• Public participation methods, including: public meetings, networking, open houses and advisory councils;
• Group process methods, including: interactive group meetings, Delphi method, nominal group techniques, and workshops.
Results of the scoping exercise are presented in an EIA Scope Document, or Terms of Reference, which describes the proposed work program.
The EIA Scope Document represents an agreement with external stakeholders on the general approach and scope of the EIA.
It forms the basis for the EIA study and preparation of the EIA document.
The proponent may wish to provide a draft EIA Scope Document for review by government and the public before preparing a final.
The EIA Scope Document can become a critical piece of process documentation should disputes among stakeholders develop during the EIA study.
It can be used to bring the study back on-track with originally agreed to terms of reference, thereby saving time and money.

16. Figure 3. Sample EIA Scope Document Table of Contents for a Hydraulic Development Project. Source: E7, 1997.

17. Impact Identification and Impact Prediction
Identification of key effects can be achieved by using one or all of the following methods:
  • compile a list of important impacts from analysis of previous projects of a similar nature in a similar environmental setting;
• use checklists, networks, matrices or map overlays to match sources of project impact with potential receptors (see EIA Tools and Methods section);
• use hypotheses of effect to map out linkages and potential impacts on the environment.
Much of this identification work may have already been done at the scoping phase where critical issues should have been defined.
After impact identification, predicting the magnitude and severity of these impacts follows. At this stage there is a need for relevant baseline information.
 The predictions must be supported by documentation of process and data.
The prediction may also contain information on the probability of a certain impact to occur and the uncertainty in the prediction.

18. Impact identification and Impact prediction Cont.
Impact/Effects prediction is the most challenging and controversial stage of the EIA process.
Development projects can set in motion a complex chain of events that can affect the environment in ways which are often difficult to predict in advance.
Reliable methods are available for predicting some environmental parameters, e.g. air quality impacts, whereas other predictions will be based more on professional judgment, e.g. impacts on wildlife populations.
Impact/Effects prediction attempts to answer the following questions:
• How will a particular project activity give rise to an impact?
• How likely is it that an impact will occur?
• What will be the magnitude of each impact?
• What will be the spatial and temporal extent of each impact?

19. Impact identification and Impact prediction Cont.
An environmental effect is defined as a reaction to a change in the environment as a result of a project action.
Distinction is often made between direct and indirect effects;
Direct effects are the immediate physical effects and alterations to the environment which follow as a direct cause-effect consequence of a project activity,
e.g. reservoir flooding can result in bioaccumulation of methyl mercury in the aquatic food chain.
Indirect effects are effects induced or stimulated by the project, and at least one step removed from a project activity in terms of cause-effect linkages,
e.g. project access road construction in a remote area can result in secondary development along the access road.

21. Quantification/Estimation of Impacts/Effects
A number of methods which are commonly used in estimating/quantifying environmental effects include :
• Pre-project experiments (e.g. toxicity testing);
• Mathematical modelling (e.g. air dispersion, hydrology and hydrodynamics, water quality, groundwater quality, erosion and sedimentation, biotic habitat, oil spills, and risk analysis);
• Physical modelling (e.g. hydraulic models or wind tunnels);
• Computer simulation (useful in assessing visual impacts of a project);
• Constraint mapping (useful for predicting impacts related to land or resource use displacement, particularly siting and routing).

22. Quantification/Estimation of Impacts/Effects Cont.
To prevent unnecessary expense, the sophistication of the prediction method should be properly matched with the scope of the EIA.
For example, a complex mathematical model of atmospheric dispersion should not be used if only small amounts of relatively harmless pollutants are expected to be emitted. Simpler models may suffice.
These types of requirements should be established and documented at the scoping phase.
All prediction techniques involve some degree of uncertainty.
It is important to recognize this uncertainty, and state probabilities and margins of error involved in predicting the likely impact of a proposed project.

23. Impact Evaluation
Once predictions are made and quantified, the next step is to decide if these predicted changes really “matter”, i.e. are significant or are perceived to be important.
The significance of environmental effects is generally evaluated in terms of ;
Their spatial extent (geographic distribution),
Duration (short vs. long-term),
Magnitude (measured level of change in a parameter and whether thresholds are being exceeded),
Reversibility (reversible versus irrevocable), and
Special sensitivity (whether an impact affects a sensitive area within the country - like a nature reserve). 

24. Impact Evaluation Cont.
Judgment of significance can be based on one or more of the following:
• Comparison with laws, regulations or accepted standards (i.e., does the project meet legal requirements, are standards exceeded?);
• Reference to pre-set criteria (such as threshold limits, dose-response relationships, conflicts with protected sites, features or species, and/or maintenance of local breeding populations);
• Consistency with government policy objectives and goals; and/or
• Social acceptance (i.e., acceptability to the local community or the general public).

25. Impact Evaluation Cont.
The impact evaluation stage usually involves utilizing a mixture of both quantitative comparison and qualitative judgment.
Impact evaluation should be undertaken in a way that allows a comparison of project alternatives and facilitates the communication of results to the public and decision-makers.
It should be tied back to issues and concerns raised during scoping exercises and issue identification.
Additional stakeholder input will likely be required during this stage of the EIA process to help determine the significance and relative importance of impacts. 

26. Impact Evaluation Cont.
Factors used in determining whether or not environmental effects are adverse include (CEA A 1994 in E7, 1997): • Negative effects on the health of biota including plants, animals, and fish • Threat to rare or endangered species • Reductions in species diversity or disruption of food webs • Loss of, or damage to, habitats, including habitat fragmentation • Discharges or release of persistent and/or toxic chemicals, microbial agents, nutrients (eg. nitrogen, phosphorus), radiation or thermal energy (eg. cooling wastewater) • Population declines, particularly in top predator, large, or long-lived species • Removal of resource materials (e.g. peat, coal) from the environment • Transformation of natural landscapes • Obstruction of migration, or passage of wildlife • Negative effects on the quality and/or quantity of the biophysical environment (e.g., surface water, groundwater, soil, land and air) • Negative effects on human health, well-being, or quality of life • Increase in unemployment or shrinkage in the economy • Detrimental change in the current use of lands and resources for traditional purposes by aboriginal persons • Negative effects on historical, archaeological, paleontological, or architectural resources • Loss of, or damage to, commercial species or resources • Foreclosure of future resource use or production • Decreased aesthetic appeal or changes in visual amenities (e.g. scenic views)

27. Impact Mitigation
If identified impacts “matter”, i.e. are significant and/or important, it is necessary to identify and implement mitigation measures.
Mitigation measures are selected to reduce or eliminate the severity of any predicted adverse environmental effects and improve the overall environmental performance and acceptability of the project.
Where mitigation is deemed appropriate, a proponent should strive to act upon effects, in the following order of priority, to:
1. Eliminate or avoid adverse effects, where reasonably achievable.
2. Reduce adverse effects to the lowest reasonably achievable level.
3. Regulate adverse effects to an acceptable level, or to an acceptable time period.
4. Create other beneficial effects to partially or fully substitute for, or counter-balance, adverse effects.
 Mitigation is an integral part of impact evaluation. It looks for better ways of doing things so that the negative impacts of the proposal are eliminated or minimized and the benefits are enhanced.

28. Impact Mitigation cont.
As soon as significant adverse impacts are identified, discussions should be held to see if they can be ‘designed out’ through changes in project design, location or operation.
It is important therefore, that there is good integration between the EIA team and project design engineers.
Where residual impacts remain after mitigation has been applied, some form of monetary or other compensation (e.g., create new fish spawning habitat, or build a new school) might be considered or required to ensure the public do not bear costs which are greater than the benefits which accrue to them from the project.
Special financial and other assistance to communities affected by the operation and construction of major facilities may be necessary.

29. Impact Mitigation cont.
Community Impact Agreements (CIAs) can be developed with host communities to ensure that assistance will be available to help local areas adjust to the possible “boom and bust” effects often associated with the construction and operation of major electricity projects.
This type of agreement might also provide a sum of money to the community to help offset identifiable local, social and community effects, and establish a monitoring program to measure the impacts on the community during construction and operation.
Mitigation and compensation measures should be identified early and properly costed and incorporated in the overall capital budget for the project to ensure that recommended actions do get carried out.
Mitigation/compensation costs can account for up to 10 percent of total project costs, but are more typically in the 3 to 5 percent range (World Bank 1991in E7, 1997).

30. Decision Making
The EIA document should describe the evaluation process and the methodology used in arriving at the recommended project, so that decision-makers are able to trace each step of the process.
The assumptions and subjective judgments used in the evaluation should be stated in the document. As well, the issues leading to and influencing the selected course of action, and any unresolved issues, should also be described.
The most acceptable alternative which emerges from the evaluation and decision-making process is usually the recommended project to be put forward in the EIA document by the proponent for approval.
Any residual effects which cannot be avoided or alleviated through mitigation or compensation measures should be described in the overall assessment section of the EIA document.
It is the job of decision-makers to assimilate all the information provided and decide if the benefits to be accrued through a project justify the potential disruptions that will occur.

32. Project Implementation
During this stage a proponent is responsible for ensuring that the environmental commitments made to regulatory agencies, lending agencies and other stakeholders during the EIA process are met.
EIA follow-up documents, such as an Impact Management Plan, should be prepared, defining for project staff and any consultants or contractors, the environmental guidelines, regulations and criteria to be followed in the design, construction and operation of the generating station including the specific comments and conditions imposed by government agencies during the EIA process.
Project specific environmental construction guidelines should be developed.
These should specify precautions and mitigation measures for construction activities, and include a plan for monitoring those activities which could have a significant environmental effect (e.g. stream crossing, dredging, dewatering).
Construction monitoring, including field inspections and surveys, should be carried out by an environmental specialist, to ensure that environmental protection requirements are being met.
It is important to plan and budget for environmental construction monitoring as part of the project.
If construction is to be contracted out, specific environmental requirements during construction should be built into construction bidding documents and contracts to ensure they are met (e.g. requirements for local hiring).

33. Impact monitoring
Environmental Impacts/effects monitoring is used to identify environmental changes resulting from the implementation of the project. In the context of EIA, effects monitoring programs are carried out to achieve the following results: 
• To ensure that the facility is meeting all environmental regulatory requirements, and that commitments made in the EIA document and/or the conditions of approval are being met;
• To test impact hypotheses, and to verify the predictions and assessment of environmental effects, thus contributing to better assessments in the future;
• To evaluate the performance effectiveness of mitigation;
• To compare actual and predicted changes to the environment, so that immediate actions can be taken to mitigate unanticipated impacts;
• To strengthen confidence by both government and the public in the EIA process, the decisions made, the station design etc., especially when a decision is made to proceed with a project with a high level of uncertainty.

34. Impact monitoring Cont.
The monitoring programs to be carried out during the construction and operation of the undertaking are normally described in the EIA document.
The effects monitoring program should include several years of pre-operational monitoring (depending on the scope of the project), and continue several years into the operation of the project.
The pre-operational phase establishes a baseline against which to measure change, while the operational phase measures the change and trends over time.
The results of the effects monitoring program should be summarized in an Environmental Effects Report.

35. EIA Auditing/Verification
In order to capitalise on the experience and knowledge gained, the last stage of an EIA is to carry out an Environmental Audit some time after completion of the project or implementation of a programme.
It will therefore usually be done by a separate team of specialists to that working on the bulk of the EIA.
 The audit should include an analysis of the technical, procedural and decision-making aspects of the EIA.
Technical aspects include: the adequacy of the baseline studies, the accuracy of predictions and the suitability of mitigation measures.
Procedural aspects include: the efficiency of the procedure, the fairness of the public involvement measures and the degree of coordination of roles and responsibilities.
Decision-making aspects include: the utility of the process for decision making and the implications for development.
The audit will determine whether recommendations and requirements made by the earlier EIA steps were incorporated successfully into project implementation.
Lessons learnt and formally described in an audit can greatly assist in future EIAs and build up the expertise and efficiency of the concerned institutions.

36. Public involvement
The degree of public involvement in EIA varies between different countries due to different legal requirements as well as to tradition.
In many countries like Sweden or the USA the public is supposed to have a large influence on the EIA process.
However, reality shows that public participation is often treated as a procedural exercise instead of a living process.
The contact with public often comes far too late in the process.
The importance of early communication with the public is essential to the success of an EIA and to the outcome of the proposed project.
The public can be providing information into the process, regarding concerns to be recognised or considered or values to be reflected.
Also in the procedural phase the public has a role as scrutinisers of the process, thereby encouraging better quality of the assessments.
There are many examples of problems connected to public opinion against projects due to lack of communication during the planning and design process.

37. Public involvement Cont.
Potential stakeholders include:
An investor;
Regulatory authorities;
Government policy makers;
Regional planners;
The local community and its representatives;
Public interest groups (i.e., nongovernment organizations or NGO’s);
Politicians
Customers
Indigenous/ Local Peoples
Resource users

38. Documentation
All pertinent information that was collected as part of the EIA process, as well as the manner in which it was assessed and the judgments used in selecting the preferred alternatives must be described in an EIA document.
The EIA document is the main vehicle for the project proponent to present their case (i.e., rationale and justification) for proceeding with a proposed development activity.
It is critical that information presented in this report is clear, focused, and useful to decision-makers.
The language of the EIA document must be clear and concise.
The information presented should be balanced, relevant, and succinct.
Detailed technical data should be generally confined to appendices or referenced to reports.
As the EIA document is used for decision making, it should focus on clarifying issues which are important to project decisions, such as trade-offs, evaluation criteria, evaluation and selection process, irreversible impacts, etc.

39. Documentation Cont.
An EIA document should typically include: • Executive Summary providing a concise discussion of significant findings and recommended actions. • Policy, legal and administrative framework within which the EIA is prepared. • Project Need/Justification. • Description of project and its alternatives in a geographic, ecological, social and temporal context. • Description of existing environment including a description of relevant physical, biological, resource use and socio-economic conditions prevailing before the project is developed. • Discussion of potential environmental impacts, both positive and negative, that are likely to result from the proposed project - including an identification of mitigation measures, residual impacts that cannot be mitigated, opportunities for environmental enhancement, and uncertainties associated with impact predictions.

40. Documentation cont.
• An analysis of alternatives, which compares design, site, technological and operational options systematically (and quantitatively where possible) in terms of potential environmental impacts, capital and operating costs, appropriateness, and institutional and monitoring requirements.
• Impact management plan including proposals for feasible and cost-effective mitigation measures that may reduce potentially significant adverse environmental impacts to acceptable levels; and compensatory measures where mitigation measures are not possible.
• A summary of the EIA for the general public
• Appendices - including a list of EIA contributors, references and record of inter-agency meetings.
Detailed data and analysis that are important but not critical to the EIAs findings should be provided in a series of support documents to the main EIA report.

41. The Length and Cost of on EIA
The length will depend on the programme, plan or project under review.
However, the process usually lasts from between 6 and 18 months from preparation through to review.
It will normally be approximately the same length as the feasibility study of which it should form an integral part.
It is essential that the EIA team and the team carrying out the feasibility study work together and not in isolation from each other.
This often provides the only opportunity for design changes to be made and mitigation measures to be incorporated in the project design.
The cost of the study will vary considerably and only very general estimates can be given here.
Typically, costs vary from between 0.1 and 0.3 percent of the total project cost for large projects over US$ 100 million and from 0.2 to 0.5 percent for projects less than US$ 100 million.
For small projects the cost could increase to between 1 and 3 percent of the project cost.

42. EIA TOOLS AND METHODS
EIA methods are generally selected to meet and reflect the nature of the project, its setting, and societal conditions.”
Some of the more commonly used tools are summarized below.
These include;
Baseline studies,
Checklists
Matrices,
Network diagrams,
Overlays,
Mathematical modelling,
Graphical comparisons
Economic techniques,

43. Baseline Studies and Checklists
Required for scoping.
Once key issues have been identified, the need for further in-depth studies can be clearly identified and any additional data collection initiated.
Specialists, preferably with local knowledge, will be needed in each key area identified.
They will need to define further data collection, to ensure that it is efficient and targeted to answer specific questions, and to quantify impacts.
A full year of baseline data is desirable to capture seasonal effects of many environmental phenomena.
However, to avoid delay in decision making, short-term data monitoring should be undertaken in parallel with long-term collection to provide conservative estimates of environmental impacts.
Checklists
A common, simple and inexpensive. These can be of different types:
Help to organise the work and identify important issues.
The risk of using checklists is that important issues not included in the checklist may exist.
Below is an example of a simple checklist used to identify impact categories.

44. A simple checklist of impact categories for land development projects
A simple checklist of impact categories for land development projects. (from Morgan 1998)
1 Local economy
Public fiscal balance
Employment
Wealth
2 Natural environment
Air quality
Water quality
Noise
Wildlife and vegetation
Natural disasters
3 Aesthetics and cultural values
Attractiveness
View opportunities
Landmarks
4 Public and private services
Drinking water
Hospital care
Crime control
Feeling of security
Fire protection
Recreation - public facilities
Recreation — informal settings
Education
Transportation - mass transit
Transportation - pedestrian
Transportation — private vehicles
Shopping
Energy services
Housing
5 Other social impacts
People displacement
Special hazards
Sociability/friendliness
Privacy
Overall contentment with neighbourhood

45. Matrices
The major use of matrices is to indicate cause and effect by listing activities along the horizontal axis and environmental parameters along the vertical axis.
In this way the impacts of both individual components of projects as well as major alternatives can be compared.
An example of a matrix is given as Table 1.
The choice of symbols in this example enables the reader to see at a glance whether or not there was an impact and, if so, whether the impact was beneficial or detrimental, temporary or permanent.
The greatest drawback of matrices is that they can only effectively illustrate primary impacts.
Network diagrams, described below, are a useful and complementary form of illustration to matrices as their main purpose is to illustrate higher order impacts and to indicate how impacts are inter-related.
Matrices help to choose between alternatives by consensus.
One method is to make pair-wise comparisons. It provides a simple way for a group of people to compare a large number of options and reduce them to a few choices.
First a matrix is drawn with all options listed both horizontally and vertically. Each option is then compared with every other one and a score of 1 assigned to the preferred option or 0.5 to both options if no preference is agreed.
An example of such a matrix is given as Table 2. As can be seen, Z is the preferred option.

46. Table 1 .Ultimate net environmental impact assessment at a glance, Feitsui reservoir

47. TABLE 2 - Example of pair-wise comparison

48. Network Diagrams
These are techniques for illustrating how impacts are related and what the consequences of impacts are.
For e.g., it may be possible to fairly accurately predict the impact of increased diversions or higher irrigation efficiencies on the low flow regime of a river. However, there may be many and far reaching secondary or tertiary consequences of a change in low flow.
These consequences can be illustrated using network diagrams. For example, reduced low flows are likely to reduce the production of fish which may or may not be of importance depending on the value (either ecological or economic) of the fish.
If fish are an important component of diet or income, the reduction may lead to a local reduction in the health status, impoverishment and possibly migration.
Also, reduced low flow coupled with increased pollution, perhaps as a result of increased agricultural industry, may further damage the fish population as well as reduce access to safe water.
Table 3 shows an example of a network diagram for a proposed plan to increase the use of groundwater for irrigation by providing subsidies for sinking deep tube wells.
This shows the primary through to quaternary impacts, as anticipated at the scoping stage.
The main crop in the area is rice. Detailed prediction work following scoping would estimate the level to which the groundwater would fall and quantify the impacts which, together with economic analysis, would clarify which impacts were most important and most likely and also determine the most suitable mitigation measures.

49. Table 3 Example of network analysis showing of a policy to utilize groundwater by subsiding tube wells

50. Overlays
Overlays provide a technique for illustrating the geographical extent of different environmental impacts.
Each overlay is a map of a single impact. For example, saline affected areas, deforested areas, limit of a groundwater pollution plume etc can be analysed and clearly demonstrated to non experts.
Manual overlay techniques can be used as an effective tool for analyzing small projects.
For large projects, geographic information systems (GIS) are favoured for map overlay analysis, due to their capacity for handling very large data sets incorporating many map layers.
Geographic Information Systems (GIS)
These are computer based systems to support the capture, management, manipulation, analysis, modelling and display of spatial data.
UNEP’s Global Resources Information Database (GRID) is a global environmental data system which assembles, processes and supplies geo-referenced environmental information to users around the world.
It is intended to be a world-wide GIS network which is accessible from any country in the world, and which can support individual project EIAs.
The most significant uses for GIS technology in EIAs are facility siting, modelling, change detection and decision support.
The scale and scope of anticipated impacts will influence the type of method selected.
In general, even the largest projects will begin with the use of checklists, matrices and network diagrams to aid in the identification of pertinent environmental components and ecosystem linkages.

51. Mathematical modelling and Economic techniques
Mathematical modelling One of the most useful tools for prediction work.
It is the natural tool to assess both flow quantities and qualities (eg salt/water balances, pollution transport, changing flood patterns).
However, it is essential to use methods with an accuracy which reflects the quality of the input data, which may be quite coarse.
It should also be appreciated that model output is not necessarily an end in itself but may be an input for assessing the impact of changes in economic, social and ecological terms.
Economic techniques Developed to try to value the environment and research work is continuing in environmental economics.
This is a specialist subject and only a brief introduction is included here.
Environmentally sound development brings long term economic benefits.
Unfortunately, short term gains are often given priority.
The most commonly used methods of project appraisal are cost-benefit and cost-effectiveness analysis.
It has not been found easy to incorporate environmental impacts into traditional cost-benefit analysis, principally because of the difficulty in quantifying and valuing environmental effects.
An EIA can provide information on the expected effects and quantify, to some extent, their importance. This information can be used by economists in the preparation of cost-benefit calculations.

52. Economic techniques cont.
Cost effectiveness analysis can also be used to determine what is the most efficient, least-cost method of meeting a given environmental objective; with costs including forgone environmental benefits.
Valuing the environment raises complex and controversial issues.
The environment is of value to the actual users (such as fishermen), to potential users (future generations or migrants), and to those who do not use it but consider its existence to have an intrinsic value (perhaps to their “quality of life”).
Clearly it is difficult to quantify such values.
Nevertheless, attempts have been made and the two most useful methods for irrigation projects in developing countries are “Effect on Production” (EOP) and “Preventive Expenditure and Replacement Costs” (PE/RC).

53. Economic techniques cont.
The EOP method attempts to represent the value of change in output that results from the environmental impact of the development.
This method is relatively easy to carry out and easily understood.
An example would be the assessment of the reduced value of fish catches due to water pollution or hydrological changes.
The PE/RC method makes an assessment of the value that people place on preserving their environment by estimating what they are prepared to pay to prevent its degradation (preventive expenditure) or to restore its original state after it has been damaged (replacement cost).
Both methods have weaknesses and must be used judiciously.
Environmental health effects present similar problems, cost-effectiveness analysis is a useful tool in the selection of mitigating or control measures, but for ex-ante project appraisal the incompatibility of human health and monetary values has forced economists to develop other techniques and indicators.

54. References
E7 Network of Expertise for the Global Environment, Environmental impact Assessment: An electric utility overview
FAO, Environmental Impact Assessment of Irrigation and Drainage Projects. FAO Irrigation and Drainage Paper 53.
FAO, Irrigation Manual: Planning, Development, Monitoring & Evaluation of Irrigated Agriculture with Farmer Participation, Volume I Module 1–6. FAO, Harare.
GoZ (2006). Environmental Management Act, Chapter 20: 27.
GWP (2006). Integrated Water Resources Management (IWRM) Tool Box Training course. Cuttysark Hotel, Zimbabwe June 2006.
Manual for Environmental Impact Assessment in Lithuania. (Undated). Ministry of the Environment of the Republic of Lithuania and Finnish Environment Institute.
Morgan, R K. (1998) "Environmental Impact Assessment" Kluwer Academic Publishers, Dordrecht