EIA Procedure for Irrigation Project

EnvironmentalImpact Assessmentof Irrigation andDrainage Projects

FAO Irrigation andDrainage Paper 53

Food and Agriculture Organizationof the United Nations

1995T.C. Dougherty - A.W. HallHR Wallingford

OVERSEAS DEVELOPMENTADMINISTRATION OF THE

UNITED KINGDOM

iTable of Contents

Preface 1Purpose 2

Acknowledgements 3

List of Abbreviations 3

Introduction 5The Need for Environmental Assessment 5

Objective 7

Using the Guide 8

The Context of Environmental Analysis 9Policy Framework 9

Social Context 10

Institutional Framework and EIA 11

Legal Framework for EIA 12

Building Institutional Capacity 14

To carry out an EIA 14

To implement the recommendations of an EIA 15

EIA Process 17Resources 19

Screening 20

Table of ContentsTable of Contents ii

Scoping 20

Prediction and Mitigation 21

Management and Monitoring 23

Auditing 24

Public Participation 25

Managing Uncertainty 27

Techniques 28

Baseline studies 28

The ICID Check-list 28

Matrices 29

Network diagrams 33

Overlays 34

Mathematical modelling 35

Expert advice 37

Economic techniques 37

Final Report - Environmental Impact Statement 38

Major Impacts of Irrigation and Drainage Projects 41Hydrology 43

Low flow regime 43

Flood regime 47

Operation of dams 47

Table of ContentsTable of Contents iii

Fall of water table 48

Rise of water table 49

Water and Air Quality 51

Solute dispersion 51

Toxic substances 52

Agrochemical pollution 55

Anaerobic effects 56

Gas emissions 56

Soil Properties and Salinity Effects 56

Soil salinity 57

Soil properties 58

Saline groundwater 59

Saline drainage 59

Saline intrusion 60

Erosion and Sedimentation 61

Local erosion 61

Hinterland effect 62

River morphology 62

Channel structures 63

Sedimentation 63

Estuary erosion 64

Table of ContentsTable of Contents iv

Biological and Ecological Change 64

Project lands 64

Water bodies 65

Surrounding area 67

Valleys and shores 67

Wetlands and plains 67

Socio-economic impacts 68

Population change 68

Income and amenity 69

Human Migration 69

Resettlement 70

Womens role 70

Minority groups 70

Sites of value 71

Regional effects 71

User involvement 71

Recreation 71

Ecological Imbalances 72

Pests and weeds 72

Animal diseases 73

Aquatic weeds 73

Table of ContentsTable of Contents v

Human Health 75

Disease ecology 76

Specific risks and counter measures 79

Health opportunities 81

Preparation of Terms of Reference 83Determining Study Requirements 83

Contents of the TOR 85

References 88Recommended Texts 88

Bibliography 89

Annex 1: Glossary 95Glossary 95

Fao Technical Papers 98FAO Irrigation and Drainage Papers 98

Environmental Impact Assessment of Irrigation and Drainage ProjectsEnvironmental Impact Assessment of Irrigation and Drainage Projects 1

Preface

The importance of environmental protection and conservation measureshas been increasingly recognized during the past two decades. It is nowgenerally accepted that economic development strategies must becompatible with environmental goals. This requires the incorporation ofenvironmental dimensions into the process of development. It is importantto make choices and decisions that will eventually promote sounddevelopment by understanding the environment functions. The UnitedNations Conference on Environment and Development (UNCED) in itsAgenda 21, Chapter 18: Protection of the Quality and Supply ofFreshwater, underscored the importance of environmental protection andconservation of the natural resource base in the context of water resourcesdevelopment for agriculture and rural development.

Much of the land currently under agriculture is deteriorating due toinappropriate planning, implementation and management. Naturalresources, particularly soil and water, are being seriously affected. Soilerosion, desertification, saliniza-tion and waterlogging reduce productivityand jeopardize long-term sustainability. Agricultural expansionprogrammes have often encompassed marginal land in many parts of theworld. Wise management of the environment requires an ability toforecast, monitor, measure and analyse envi-ronmental trends and assessthe capabilities of land and water at different levels, ranging from a smallirrigated plot to a catchment. Adoption of environmental impactassessments (EIAs) will enable countries to plan water and land use in anintegrated manner, avoiding irreversible environmental damage. Contraryto common perceptions, this would lead to higher economic benefits andsustainable resource use.

Irrigation and drainage projects invariably result in many far-reachingecological changes. Some of these benefit human population, while othersthreaten the long-term productivity of the irriga-tion and drainage projectsthemselves as well as the natural resource base. The undesirable changes arenot solely restricted to increasing pollution or loss of habitat for native plantsand animals; they cover the entire range of environmental components, suchas soil, water, air, energy, and the socio-economic system.

An increasing number of developing countries are accepting theprinciple of environmental screening of development projects at theplanning stage and hence are looking for guidelines to environmentalimpact assessments. Many multi- and bilateral agencies stipulate

environmental impact assessments of proposed developments as acondition for lending, technical assistance and development support.FAO has, for quite some time now, been emphasizing the environmentalimpacts of irrigation and drainage projects, and provided technicalassistance to a number of countries in evaluating environmental impacts.

The challenge now is to provide the appropriate tools to those whowish to undertake environ-men-tal impact assessment in irrigation anddrainage projects; a guide to a systematic approach to developing abasic understanding of the environmental problems and a methodologyto assess the scope and magnitude of environmental damage that may becaused by irrigation and drain-age. Despite many publications in recenttimes, it is felt that an appropriate guide is still lacking. The need for anobjective EIA guide with focus on methodology that is applicable todeveloping countries is indeed great. It was in this context that actionwas taken, jointly by FAO and the Overseas Development Administration(ODA) of the United Kingdom, to develop a guide to undertakeenvironmental impact assessment of irrigation and drainage projects indeveloping countries.

The guide is a follow-up to the ICID environmental checklist. It takesadvantage of some existing guidelines as well as country studies inenvironmental impact assessments.

PURPOSE

The aim of this publication is to provide guidance to personnel workingin irrigation and drainage to enable them to take into account theenvironmental impacts of such developments. The main focus of thedocument is on the process of undertaking environmental impactassessment. In addition, major environmental impacts of irrigation anddrainage projects are discussed in detail. Guidance is also provided forpreparing terms of reference for undertaking an environmental impactassessment study. A list of recommended texts and bibliography will helpthe reader to obtain additional information on the subject.

The document was first presented at the VIIIth International WaterResearch Association World Con-gress, Cairo, Egypt, 1994, andsubsequently submitted for comments to the Environment Working Groupof the International Commission on Irrigation and Drainage and the JointWHO/ FAO/UNEP/UNCHS Panel of Experts on EnvironmentalManagement for Vector Control.


ACKNOWLEDGEMENTS

The authors wish to acknowledge the considerable assistance providedby Dr. Arumugam Kandiah of the Land and Water Development Divisionof FAO, Random Dubois of the FAO Investment Centre and theircolleagues at FAO. Also Robert Bos, Executive Secretary of PEEM, made amajor contribution, in particular to the section Human health. Othernotable contributors include Peter Furu (Danish Bilharzia Laboratory),Alfred Heuperman (Institute of Sustainable Irrigated Agriculture, Victoria,Australia), Dr. A Mauderli and Martin Fritsch (Institute for LandImprovement and Water Management (ETH), Zrich, Switzerland), andWolfram Dirksen (German National Committee of the ICID). Thepublication was reformatted and prepared for printing by Han Kamphuisand Chrissi Redfern. The authors wish to thank the above, and others toonumerous to mention, for their contributions to this Guide.

LIST OF ABBREVIATIONS

ADB Asian Development BankAfDB African Development BankCWC Central Water Commission of IndiaEA, EIA Environmental Assessment, Environmental Impact Assessment.EAP/EMP Environmental Action / Management PlanEBRD European Bank for Reconstruction and DevelopmentEC Electrical ConductivityEIRR Economic Internal Rate of ReturnEIS Environmental Impact StatementEOP Effect on ProductionEPA Environmental Protection AgencyERL Environmental Resources LimitedESCAP Economic and Social Commission for Asia and the PacificFAO Food and Agriculture Organization of the United Nations GIS Geographic Information SystemGTZ Deutsche Gesellschaft fr Technische Zusammenarbeit

(German Agency for Technical Co-operation)ICID International Commission on Irrigation and DrainageICOLD International Commission on Large DamsIEE Initial Environmental Examination / EvaluationILO International Labour OrganizationIPCS International Programme on Chemical SafetyIUCN International Union for the Conservation of NatureIWRA International Water Research AssociationNGO Non-Governmental OrganizationODA Overseas Development Administration of the UKOECD Organization for Economic Cooperation and Development


PEEM Panel of Experts on Environmental Management for vector control (a joint acti-vi-ty of WHO, FAO, UNEP and UNCHS)

PE/RC Preventative Expenditure / Replacement CostsSAR Sodium Adsorption RatioTOR Terms of ReferenceUK United KingdomUNCHS United Nations Centre for Human SettlementsUNECE United Nations Economic Commission for EuropeUNEP United Nations Environment ProgrammeUSA United States of AmericaWHO World Health Organization


Introduction

THE NEED FOR ENVIRONMENTAL ASSESSMENT

Economic, social and environmental change is inherent todevelopment. Whilst development aims to bring about positive change itcan lead to conflicts. In the past, the promotion of economic growth as themotor for increased well-being was the main development thrust with littlesensitivity to adverse social or environmental impacts. The need to avoidadverse impacts and to ensure long term benefits led to the concept ofsustainability. This has become accepted as an essential feature ofdevelopment if the aim of increased well-being and greater equity infulfilling basic needs is to be met for this and future generations.

In order to predict environmental impacts of any development activityand to provide an opportunity to mitigate against negative impacts andenhance positive impacts, the environmental impact assessment (EIA)procedure was developed in the 1970s. An EIA may be defined as:

a formal process to predict the environmental consequences of humandevelopment activities and to plan appropriate measures to eliminate orreduce adverse effects and to augment positive effects.

EIA thus has three main functions:

to predict problems, to find ways to avoid them, and to enhance positive effects.

The third function is of particular importance. The EIA provides a uniqueopportunity to demonstrate ways in which the environment may be improvedas part of the development process. The EIA also predicts the conflicts andconstraints between the proposed project, programme or sectoral plan and itsenvironment. It provides an opportunity for mitigation measures to beincorporated to minimize problems. It enables monitoring programmes to beestablished to assess future impacts and provide data on which managers cantake informed decisions to avoid environmental damage.

EIA is a management tool for planners and decision makers andcomplements other project studies on engineering and economics.Environmental assessment is now accepted as an essential part of


development planning and management. It should become as familiar andimportant as economic analysis in project evaluation.

The aim of any EIA should be to facilitate sustainable development.Beneficial environmental effects are maximized while adverse effects areameliorated or avoided to the greatest extent possible. EIA will help selectand design projects, programmes or plans with long term viability andtherefore improve cost effectiveness.

It is important that an EIA is not just considered as part of the approvalprocess. Volumes of reports produced for such a purpose, which areneither read nor acted upon, will devalue the process. A key output of theEIA should be an action plan to be followed during implementation andafter implementation during the monitoring phase. To enable the actionplan to be effective the EIA may also recommend changes to laws andinstitutional structures.

Initially EIA was seen by some project promoters as a constraint todevelopment but this view is gradually disappearing. It can, however, be auseful constraint to unsustainable development. It is now well understoodthat environment and development are complementary andinterdependent and EIA is a technique for ensuring that the two aremutually reinforcing. A study carried out by the Environmental ProtectionAgency (USA) in 1980 showed that there were significant changes toprojects during the EIA process, marked improvements in environmentalprotection measures and net financial benefits. The costs of EIA preparationand any delays were more than covered by savings accruing frommodifications, (Wathern, 1988).

Irrigated agriculture is crucial to the economy, health and welfare of avery large part of the developing world. It is too important to bemarginalized as it is vital for world food security. However, irrigatedagriculture often radically changes land use and is a major consumer offreshwater. Irrigation development thus has a major impact on theenvironment. All new irrigation and drainage development results in someform of degradation. It is necessary to determine the acceptable level andto compensate for the degradation. This degradation may extend bothupstream and downstream of the irrigated area. The impacts may be bothto the natural, physical environment and to the human environment. Allmajor donors consider large irrigation and drainage developments to beenvironmentally sensitive.

An EIA is concerned both with impacts of irrigation and drainage on theenvironment and with the sustainability of irrigation and drainage itself.Clearly an EIA will not resolve all problems. There will be trade-offsbetween economic development and environmental protection as in all


development activities. However, without an objective EIA, informeddecision making would be impossible.

OBJECTIVE

This guide aims to assist staff in developing countries from variousdisciplines and backgrounds (government officials, consultants, planners)to incorporate environmental considerations into planning, designing,implementing and regulating irrigation and drainage programmes, plansand projects, thus leading to sustainable projects. The guide aims to be ofgeneral use throughout the developing world and has three mainfunctions:

to describe the methodology and output of an EIA; to provide inter-disciplinary advice related to irrigation and drainage

to those engaged in preparing EIAs; and, to enhance institutional capacity for carrying out an EIA.

In developing countries irrigation development is mainly theresponsibility of the public sector. This document therefore concentrates onpublic sector irrigation projects. Whilst national irrigation authorities willnot usually carry out EIAs, they will commission them, either as part of afeasibility study or separately. They must therefore be familiar with EIA inorder to formulate the terms of reference and to appraise the impactstatement. Private developers should also be required to demonstrate thattheir proposals are environmentally sound.

The objective has been to produce a brief reference text that will be ofmost benefit to non-specialists in developing countries who are perhapsfacing the need to carry out an environmental assessment for the first time.To ensure brevity, and accessibility to all readers, technical, scientific orengineering content has been kept to a minimum. It is assumed that thisinformation is readily available in other textbooks or manuals and thatmany readers will already be familiar with some technical aspects.

Similarly, no detailed explanation of the philosophy of EIA is given asthis is available in standard general texts. Throughout the guide the termsEIA and environmental assessment have been used synonymously. Aglossary of terms and abbreviations used in the text are included in Annex1. Chapter 6 provides a guide to other publications considered of most usethat are also widely available. Recommended texts, which are consideredparticularly useful, are reviewed at the start of Chapter 6.


USING THE GUIDE

Environmental assessment is appropriate for both site specific projectsand wider programmes or plans covering projects or sectoral activities overa wide geographic area. In this document the term project is usedinterchangeably for both the site specific and wider meaning.Rehabilitation or modernization programmes are more common than newgreen field projects and raise special issues which need to be addressed byan EIA. They provide more opportunities to correct situations where theenvironment is adversely affected and they are usually richer in availabledata, (Tiffen, 1989). Also, operation and maintenance reforms for regionsor basins will benefit greatly from an EIA. As this guide has beenspecifically prepared to address irrigation and drainage projects, plans andprogrammes, it is not sufficiently comprehensive to be used to carry outenvironmental impact assessments of other water resources projects.

Initially EIA was used for specific, particularly large scale, projects suchas dams, which have obvious long-term consequences. Now, however,greater attention is given to the wider relationship between developmentand the environment. The relatively insignificant actions of manyindividual people may cumulatively have a much greater impact on theenvironment than a single construction project. For example a programmeto support small-holder development, through agricultural credit schemesto Water User Groups, may not warrant an EIA if each scheme isconsidered in isolation. However, the impact within a river basin or in thewater sector in a region can be significant. A sectoral or basin-wide EIAwould enable an assessment of the collective impact of the programme. Ina further example from Tamil Nadu, India, a decision was made to providefree electricity to farmers to pump water for irrigation. Whilst thisincreased agricultural production it also led to groundwater mining: thereduction in the groundwater level in some areas has resulted in severeenvironmental and economic problems.

To enable the EIA process to be of maximum benefit, it must beincorporated into the planning process of a country. The social,institutional and legal issues concerned with the effective use of EIA arecovered in Chapter 2. Chapter 5, on how to prepare terms of refe-rence,has been prepared to assist those who need to employ others to carry outEIAs on their behalf. The mechanics of carrying out an EIA together with adescription of the possible environmental impacts of irrigation anddrainage are described, respectively, in Chapters 3 and 4.


The Context of Environmental Analysis

POLICY FRAMEWORK

Increasingly, at the national level, new environmental policies are beingintroduced, perhaps including a National Environmental Action Plan orNational Plan for Sustainable Development. Such policies are oftensupported by legislation. Government policies in areas such as water, landdistribution and food production, especially if supported by legislation, arelikely to be highly significant for irrigation and drainage projects. An EIAshould outline the policy environment relevant to the study in question.Results are also likely to be most easily understood if they are interpretedin the light of prevailing policies.

Policies and regulations are sometimes conflicting and can contribute todegradation. It is within the scope of an EIA to highlight such conflicts anddetail their consequences in relation to the irrigation and drainageproposal under study. An example of conflicting policies would be anagricultural policy to subsidize agro-chemicals to increase production andan environmental policy to limit the availability of persistent chemicals. Atotally laissez-faire policy will result in unsustainable development, forexample through uncontrolled pollution and distortions in wealth. Thiscreates problems which future generations have to resolve. On the otherhand, excessive government control of market forces may also havenegative environmental impacts. For example, free irrigation water leads tothe inefficient use of this scarce and expensive resource, inequitiesbetween head and tail users and waterlogging and salinity problems.

Legal and policy issues have far-reaching consequences for theenvironment and are included here to illustrate the complex nature ofenvironmental issues. The FAO Legislative Study 38, The environmentalimpact of economic incentives for agricultural production: a comparativelaw study, is a useful reference. A forthcoming FAO/World Bank/UNDPpublication, Water Sector Policy Review and Strategy Formulation: AGeneral Framework, will address the need for environmental issues to beintegrated into water policy. If a regional, sector or basin-wide EIA isneeded, such issues will form an important part.


SOCIAL CONTEXT

A project or programme and its environmental impacts exist within asocial framework. The context in which an EIA is carried out will beunique and stereotype solutions to environmental assessments aretherefore not possible. Cultural practices, institutional structures and legalarrangements, which form the basis of social structure, vary from countryto country and sometimes, within a country, from one region to another. Itis a fundamental requirement to understand the social structure of the areaunder study as it will have a direct impact on the project and the EIA.

Local, regional and national regulations, laws and organizationsareinterlinked. The way in which they are interlinked needs to be explicitlyunderstood as part of the EIA. An understanding of the institutional andlegal framework concerning the environment and irrigation and drainagedevelopment is critical to the success of any project or programme.Indeed, it is likely that recommendations arising from the EIA will includerestructuring or strengthening institutions, particularly at a local level, forexample, ensuring adequate maintenance or effective monitoring of drainwater quality. Recommendations for new legal controls or limits may alsoform part of the EIA output; for example, stipulating a particular flowregime in order to maintain a wetland.

At a local or regional level there may be particular regulations andcustomary practices which will influence environmental aspects of anyproject and these must be understood. The participation of local groupsand the direct beneficiaries, mainly farmers, is essential to successful EIA.This may best be achieved by involving district councils. At the districtlevel there is more interaction between sectors. Consultation with localinterest groups, including non-governmental organizations (NGOs), willenable local views to be taken into account and their concerns addressed.An awareness of social and cultural problems may enable solutions to befound and conflicts to be averted before project implementationcommences. Ignorance of a problem will prevent a satisfactory solutionbeing found.

If land acquisition, economic rehabilitation (providing an alternativesource of income) or resettlement of displaced people are factors in anyproposed development, special care will be needed in carrying out theEIA. In most countries such issues are socially and politically sensitive andlegally complex and must be identified early, during screening. Theyshould be highlighted so that they are adequately studied by experts earlyin project preparation.

Poor people often find themselves in a vicious circle. They are forced bytheir poverty to exploit natural resources in an unsustainable manner and


suffer from increasing poverty because of environmental degradation. Theyoften inhabit fragile, marginal eco-zones in rural and, increasingly, semi-urban areas. High population growth is linked to poverty and furthercontributes to the dynamics of the vicious circle as ever increasingdemands are made on finite natural resources. Therefore, the needs of thepoor, their influence on the project and the projects impact on vulnerablegroups all require particular attention in an EIA.

INSTITUTIONAL FRAMEWORK AND EIA

Environmental, water and land issues involve many disciplines andmany government bodies. Data will therefore have to be collected andcollated from a wide range of technical ministries, other governmentauthorities and parastatals. The interests of some bodies may not initiallyappear to be relevant to irrigation and drainage. However, they may holdimportant information about the project and surrounding area on suchtopics as land tenure, health, ecology and demography.

The link between different ministries and departments within ministriesare often complex and the hierarchy for decision making unclear. There isa tendency for each ministry to guard its project and not consult or seekinformation from other government bodies unless forced to. This is directlycontrary to the needs of an EIA. Even if formal structures exist there maybe a lack of coordination between different organizations. Informal linksmay have been established in practice in order to overcome awkwardbureaucratic structures. These issues must be understood and notoversimplified.

There may be conflict between government organizations, particularlybetween the institution promoting the development and that given themandate for environmental protection. In countries where some planningprocesses are undertaken at the regional or district level, the regional ordistrict councils make it easier for affected communities to put forwardtheir views, which may differ from those of the central authorities. Theywill have different agendas and approaches. The EIA process must beinteractive and be sympathetic to the differing views; not biased towards aparticular organization.

One of the main conflicts arising from irrigation and drainage projectsis between those responsible for agriculture and those for water. In somecountries, there are several key ministries with differing responsibility, suchas agriculture, public works and irrigation, plus several parastatalorganizations and special authorities or commissions, some perhapsdirectly under the Office of the President. The institutional aspects arecomplex; for example in Thailand, over 15 institutions have responsibilityfor various aspects of soil conservation work.


Increasingly, at the national level, new institutions are being created, orexisting institutions reorganized, to address environmental issues. Often aMinistry of the Environment will be created with a mandate to preparelegislation, set standards and provide a policing role. In addition, anEnvironmental Protection Agency may also be created to coordinateenvironmental assessment activities and to monitor follow up actions.As well as specific environmental agencies, new units or departmentsconcerned with environmental issues are being created in technicalministries. Such units may have narrow duties related to the responsibilitiesof the institution. For example, several units could be concerned withvarious aspects of monitoring water pollution levels and setting acceptablequality standards. The responsibilities of all the relevant institutions needsto be clearly understood.

Institutional weakness is one of the major reasons for environmentallyunsound development. The multiplicity of institutions may also mitigateagainst effective enforcement of environmental control measures.The EIA must cover such issues in depth and highlight contradictions,weak or impractical legislation and institutional conflicts. To overcomesuch problems an EIA should propose appropriate solutions. This shouldinclude institutional strengthening.

LEGAL FRAMEWORK FOR EIA

Environmental policy without appropriate legislation will be ineffectiveas, in turn, will be legislation without enforcement. Economic andfinancial pressures will tend to dominate other concerns. In manydeveloping countries legislation on environmental issues has been inexistence for many years. For example, laws exist in most countries for theprevention of water pollution, the protection of cultural heritage and forminimum compensation flows. Much of the existing legislation orregulations have not been considered environmental. Recently, muchspecific new environmental legislation has been enacted. This may be as aresponse to major disasters, or may result from government policy, publicpressure or the general increased international awareness of theenvironmental dangers that now exist in the world. Relevant water andland law as well as environmental protection legislation needs stating,understanding and analysing as part of an EIA.

New legislation may include a statutory requirement for an EIA to bedone in a prescribed manner for specific development activities. Whencarrying out an EIA it is thus essential to be fully aware of the statutoryrequirements and the legal responsibilities of the concerned institutions.These are best given as an annex to the terms of reference. The legalrequirements of the country must be satisfied. New laws can impose an


enormous burden on the responsible agencies. The statutory requirementto carry out an EIA for specific projects will, for example, require expertstaff to carry out the study, as well as officials to review the EIA andapprove the project.

Laws designating what projects require EIA should, ideally, limit thestatutory requirements to prevent EIA merely becoming a hurdle in theapproval process. This will prevent large volumes of work being carriedout for little purpose. Most legislation lists projects for which EIA is adiscretionary requirement. The discretionary authority is usually the samebody that approves an EIA. This arrangement allows limited resources to beallocated most effectively. However, it is essential that the discretionaryauthority is publicly accountable.

When external financial support is required it will also be necessary tosatisfy the obligations of the donor organization. Most major donors nowrequire an EIA for projects relating to irrigation and drainage. Chapter 6gives details of publications outlining the requirements of the main donors.

The function of environmental legislation can vary. It is not easy to givea precise definition of when an EIA is needed. Therefore the statutoryrequirement for an EIA is not particularly well suited to law. On the otherhand many of the most important environmental hazards are easilyaddressed by law. For example, it is straightforward to set legal limits forpollution, flow levels, compensation etc: here the problem is one ofenforcement. It is normal for an EIA to assess the acceptability or severityof impacts in relation to legal limits and standards. However, it isimportant to highlight cases where existing standards are insufficientlystringent to prevent adverse impacts and to recommend acceptablestandards. Enforcement problems can be partially addressed by changinginstitutional structures.

Laws relating to irrigated lands are complex and according to an FAOstudy of five African countries they are not generally applied (FAO, 1992).There are conflicts between modern and customary laws: the former tendto be given prominence although the latter are usually strong locally.Traditional and customary rights have often developed in very differenthistorical and political contexts and can vary greatly over a short distance.They may also be mainly oral and imprecise. Local participation in thepreparation of the EIA will help to understand important customary rightsand highlight possible weaknesses in any proposed development.


BUILDING INSTITUTIONAL CAPACITY

To carry out an EIA

It may be desirable to have both a Ministry of the Environment (whichwill have responsibility for setting norms and new legislation) and anEnvironmental Protection Agency, EPA, (as a coordinating authority toorchestrate the cross-sectoral EIA activity). Whatever the institutionalstructure, the ministry promoting the development will usually be requiredto carry out an EIA or to commission others to carry it out on their behalf.The EIA will then be approved or otherwise by the central regulatingauthorities. To enable this process to function satisfactorily trained staff willbe required in:

the environmental authority for commissioning and effective reviewand approval of EIAs;

the technical authority for carrying out EIAs or preparing terms ofreference or guidelines for others to do the work; and,

Universities and the private sector, should the work be put out tocontract.

There is thus a clear need for skilled professional staff in a variety oforganizations who are familiar and competent with EIAs.

To achieve the required skills, training should cover all educationallevels. Environmental studies should be introduced in schools anduniversities so that future expertise is nurtured. In-service training for bothprofessional staff and technicians is important. Senior planners anddecision makers also need to attend short environmental awarenessprogrammes so that they appreciate the issues raised in EIA reports andcan make enlightened decisions.

If environmental assessment is a statutory requirement, local expertisewill be needed to carry out the work that this will impose. For largeprojects, with external financial support, foreign expertise may be used butthis would not be viable for most projects. Foreign consultants, becausethey are outsiders, are at a disadvantage in making recommendations thatare realistic and implementable. Local expertise, for both the public andprivate sectors, must be developed through adequately funded training andtechnology transfer programmes. Training should focus on the skills neededfor an intersectoral decision making process at the crucial points in theproject cycle. It should not aim to make pseudo EIA specialists out of othertechnical specialists.


In those countries where there is no central environmental authorityand no statutory regulations for EIA the need for skilled staff will beequally important but less obvious. The pressure to carry out an EIA maycome from external donors, the general public or specific pressure groups.In this case those who carry out the work may come from a small pool ofacademics or from external consultants. Part of their remit should be totrain counterparts in government service. This situation is unsatisfactory inthe long-term and will tend to restrict EIA to only the largest and mostcontroversial projects. Governments must address this problem byappropriate policies for environmental protection and adequate resourcesto train skilled staff to carry out the work.

EIA is not a subject in itself but a procedure which relies on expertisefrom many disciplines. Training should not therefore be solely targeted toenvironmental scientists or ecologists. It is important that training isprovided for specialists in all disciplines involved in an EIA, from scientiststo sociologists and engineers to economists, so that they can contribute tomeaningful EIAs. An important, but highly specialized area of training is inthe health aspects of irrigation development. The PEEM Secretariatorganizes an intersectoral course on health opportunities in waterresources development which is held in developing countries.

Data are essential to an EIA and the organizations responsible for datacollection and analysis, for meteorology, hydrology, water quality etc,should be strengthened (or established if not already existing). Theorganizations must be well funded so that the data collected are reliableand complete and the staff well trained and motivated. Inadequate andunreliable data will result in poor studies based purely on qualitativeanalysis which can be subjective and easily refuted.

To implement the recommendations of an EIA

As part of an EIA, it may be necessary to consider how existingorganizations will need to be changed or new laws promulgated in orderto ensure environmentally sustainable development. The implementationof mitigating measures or monitoring will often have an impact on thework of one or several institutions. It will therefore be necessary torecommend precisely the structure and role of new units within anorganization or the restructuring of existing units, so that the proposedmeasures can be implemented effectively.

The EIA should also give recommendations on local capacity building.Definition of such local needs may involve several national and localgovernment authorities, NGOs or other participatory groups such as WaterUsers Associations and academic institutions. It is crucial that local and


not just central government institutional capacity is strengthened. This willhelp to overcome the feeling that environmental issues are imposed from aremote central authority and are a diversion from more importantdevelopment activities. It will also build into project planning theimportance of environmental management.

Once a project has been approved, responsibility for ensuring that EIArecommendations are implemented may fall to a weak unit within theexecuting agency. This institutional weakness can considerably devalue anEIA and render it a mere hurdle on the path to implementation to bediscarded once a project starts. When preparing an EIA it is essential thatthe environmental authorities are identified and strengthened to ensurethey are not toothless. The authority responsible for project implementationshould be accountable to watchdog environmental agencies. One way ofensuring this would be to link budget allocations from the Ministry ofFinance/Planning to satisfactory performance.


EIA Process

The EIA process makes sure that environmental issues are raised when aproject or plan is first discussed and that all concerns are addressed as aproject gains momentum through to implementation. Recommendationsmade by the EIA may necessitate the redesign of some projectcomponents, require further studies, suggest changes which alter theeconomic viability of the project or cause a delay in projectimplementation. To be of most benefit it is essential that an environmentalassessment is carried out to determine significant impacts early in theproject cycle so that recommendations can be built into the design andcost-benefit analysis without causing major delays or increased designcosts. To be effective once implementation has commenced, the EIAshould lead to a mechanism whereby adequate monitoring is undertakento realize environmental management. An important output from the EIAprocess should be the delineation of enabling mechanisms for sucheffective management.

The way in which an EIA is carried out is not rigid: it is a processcomprising a series of steps. These steps are outlined below and thetechniques more commonly used in EIA are described in some detail inthe section Techniques. The main steps in the EIA process are:

screening scoping prediction and mitigation management and monitoring audit

Figure 1 shows a general flow diagram of the EIA process, how it fits inwith parallel technical and economic studies and the role of publicparticipation. In some cases, such as small-scale irrigation schemes, thetransition from identification through to detailed design may be rapid andsome steps in the EIA procedure may be omitted.



FIGURE 1 - Flow diagram of the EIA process and parallel studies

Screening often results in a categorization of the project and from thisa decision is made on whether or not a full EIA is to be carried out.

Scoping is the process of determining which are the most criticalissues to study and will involve community participation to somedegree. It is at this early stage that EIA can most strongly influence theoutline proposal.

Detailed prediction and mitigation studies follow scoping and arecarried out in parallel with feasibility studies.

The main output report is called an Environmental Impact Statement,and contains a detailed plan for managing and monitoringenvironmental impacts both during and after implementation.

Finally, an audit of the EIA process is carried out some time afterimplementation. The audit serves a useful feedback and learningfunction.

RESOURCES

An EIA team for an irrigation and drainage study is likely to becomposed of some or all of the following: a team leader; a hydrologist; anirrigation / drainage engineer; a fisheries biologist/ecologist; anagronomist/pesticide expert; a soil conservation expert; abiological/environmental scientist; an economist, a social scientist and ahealth scientist (preferably a epidemiologist). The final structure of the teamwill vary depending on the project. Specialists may also be required forfieldwork, laboratory testing, library research, data processing, surveys andmodelling. The team leader will require significant management skill to co-ordinate the work of a team with diverse skills and knowledge.

There will be a large number of people involved in EIA apart from thefull-time team members. These people will be based in a wide range oforganizations, such as the project proposing and authorizing bodies,regulatory authorities and various interest groups. Such personnel wouldbe located in various agencies and also in the private sector; aconsiderable number will need specific EIA training.

The length of the EIA will obviously depend on the programme, plan orproject under review. However, the process usually lasts from between 6and 18 months from preparation through to review. It will normally beapproximately the same length as the feasibility study of which it shouldform an integral part. It is essential that the EIA team and the team carryingout the feasibility study work together and not in isolation from each other.This often provides the only opportunity for design changes to be madeand mitigation measures to be incorporated in the project design.


The cost of the study will vary considerably and only very generalestimates can be given here. Typically, costs vary from between 0.1 and0.3 percent of the total project cost for large pro-jects over US$ 100million 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 ofthe project cost.

SCREENING

Screening is the process of deciding on whether an EIA is required. Thismay be determined by size (eg greater than a predetermined surface areaof irrigated land that would be affected, more than a certain percentage orflow to be diverted or more than a certain capital expenditure).Alternatively it may be based on site-specific information. For example, therepair of a recently destroyed diversion structure is unlikely to require anEIA whilst a major new headwork structure may. Guidelines for whether ornot an EIA is required will be country specific depending on the laws ornorms in operation. Legislation often specifies the criteria for screeningand full EIA. All major donors screen projects presented for financing todecide whether an EIA is required.

The output from the screening process is often a document called anInitial Environmental Examination or Evaluation (IEE). The mainconclusion will be a classification of the project according to its likelyenvironmental sensitivity. This will determine whether an EIA is neededand if so to what detail.

SCOPING

Scoping occurs early in the project cycle at the same time as outlineplanning and pre-feasibility studies. Scoping is the process of identifyingthe key environmental issues and is perhaps the most important step in anEIA. Several groups, particularly decision makers, the local population andthe scientific community, have an interest in helping to deliberate theissues which should be considered, and scoping is designed to canvasstheir views, (Wathern 1988).

Scoping is important for two reasons. First, so that problems can bepinpointed early allowing mitigating design changes to be made beforeexpensive detailed work is carried out. Second, to ensure that detailedprediction work is only carried out for important issues. It is not thepurpose of an EIA to carry out exhaustive studies on all environmentalimpacts for all projects. If key issues are identified and a full scale EIAconsidered necessary then the scoping should include terms of referencefor these further studies.


At this stage the option exists for cancelling or drastically revising theproject should major environmental problems be identified. Equally it maybe the end of the EIA process should the impacts be found to beinsignificant. Once this stage has passed, the opportunity for majorchanges to the project is restricted.

Before the scoping exercise can be fully started, the remit of the studyneeds to be defined and agreed by the relevant parties. These will varydepending on the institutional structure. At a minimum, those who shouldcontribute to determining the remit will include those who decide whethera policy or project is implemented, those carrying out the EIA (orresponsible for having it carried out by others) and those carrying outparallel engineering and economic studies relating to the proposal.Chapter 5 gives details on preparing terms of reference for an EIA. Acritical issue to determine is the breadth of the study. For example, if aproposed project is to increase the area of irrigated agriculture in a regionby 10%, is the remit of the EIA to study the proposal only or also toconsider options that would have the same effect on production?

A major activity of scoping is to identify key interest groups, bothgovernmental and non-governmental, and to establish good lines ofcommunication. People who are affected by the project need to hearabout it as soon as possible. Their knowledge and perspectives may have amajor bearing on the focus of the EIA. Rapid rural appraisal techniquesprovide a means of assessing the needs and views of the affectedpopulation.

The main EIA techniques used in scoping are baseline studies,checklists, matrices and network diagrams. These techniques collect andpresent knowledge and information in a straightforward way so that logicaldecisions can be made about which impacts are most significant. Risk anduncertainty are discussed further in the section Managing uncertainty.

PREDICTION AND MITIGATION

Once the scoping exercise is complete and the major impacts to bestudied have been identified, prediction work can start. This stage formsthe central part of an EIA. Several major options are likely to have beenproposed either at the scoping stage or before and each option mayrequire separate prediction studies. Realistic and affordable mitigatingmeasures cannot be proposed without first estimating the scope of theimpacts, which should be in monetary terms wherever possible. It thenbecomes important to quantify the impact of the suggested improvementsby further prediction work. Clearly, options need to be discarded as soonas their unsuitability can be proved or alternatives shown to be superior inenvironmental or economic terms, or both. It is also important to test thewithout project scenario.


An important outcome of this stage will be recommendations formitigating measures. This would be contained in the Environmental ImpactStatement. Clearly the aim will be to introduce measures which minimizeany identified adverse impacts and enhance positive impacts. Formal andinformal communication links need to be established with teams carryingout feasibility studies so that their work can take proposals into account.Similarly, feasibility studies may indicate that some options are technicallyor economically unacceptable and thus environmental prediction work forthese options will not be required.

Many mitigating measures do not define physical changes but requiremanagement or institutional changes or additional investment, such as forhealth services. Mitigating measures may also be procedural changes, forexample, the introduction of, or increase in, irrigation service fees topromote efficiency and water conservation. Table 6 in Chapter 4 describesthe most common adverse impacts associated with irrigation and drainageschemes and some appropriate mitigating measures.

By the time prediction and mitigation are undertaken, the projectpreparation will be advanced and a decision will most likely have beenmade to proceed with the project. Considerable expenditure may havealready been made and budgets allocated for the implementation of theproject. Major changes could be disruptive to project processing and onlyaccepted if prediction shows that impacts will be considerably worse thanoriginally identified at the scoping stage. For example, an acceptablemeasure might be to alter the mode of operation of a reservoir to protectdownstream fisheries, but a measure proposing an alternative to damconstruction could be highly contentious at this stage. To avoid conflict itis important that the EIA process commences early in the project cycle.

This phase of an EIA will require good management of a wide range oftechnical specia-lists with particular emphasis on:

prediction methods; interpretation of predictions, with and without mitigating measures; assessment of comparisons.

It is important to assess the required level of accuracy of predictions.Mathematical modelling is a valuable technique, but care must be taken tochoose models that suit the available data. Because of the level ofavailable knowledge and the complexity of the systems, physical systemsare modelled more successfully than ecological systems which in turn aremore successfully modelled than social systems. Social studies (includinginstitutional capacity studies) will probably produce output in non-numerical terms. Expert advice, particularly from experts familiar with thelocality, can provide quantification of impacts that cannot be modelled.Various techniques are available to remove the bias of individual opinion.


Checklists, matrices, networks diagrams, graphical comparisons andoverlays, are all techniques developed to help carry out an EIA and presentthe results of an EIA in a format useful for comparing options. The mainquantifiable methods of comparing options are by applying weightings, toenvironmental impacts or using economic cost-benefit analysis or acombination of the two. Numerical values, or weightings, can be applied todifferent environmental impacts to (subjectively) define their relativeimportance. Assigning economic values to all environmental impacts is notrecommended as the issues are obscured by the single, final answer.However, economic techniques, can provide insight into comparativeimportance where different environmental impacts are to be compared, suchas either losing more wetlands or resettling a greater number of people.

When comparing a range of proposals or a variety of mitigation orenhancement activities, a number of characteristics of different impactsneed to be highlighted. The relative importance of impacts needs agreeing,usually following a method of reaching a consensus but includingeconomic considerations. The uncertainty in predicting the impact shouldbe clearly noted. Finally, the time frame in which the impact will occurshould be indicated, including whether or not the impact is irreversible.

MANAGEMENT AND MONITORING

The part of the EIS covering monitoring and management is oftenreferred to as the Environmental Action Plan or EnvironmentalManagement Plan. This section not only sets out the mitigation measuresneeded for environmental management, both in the short and long term,but also the institutional requirements for implementation. The terminstitutional is used here in its broadest context to encompassrelationships:

established by law between individuals and government; between individuals and groups involved in economic transactions; developed to articulate legal, financial and administrative links

among public agencies; motivated by socio-psychological stimuli among groups and

individuals (Craine, 1971).

The above list highlights the breadth of options available forenvironmental management, namely: changes in law; changes in prices;changes in governmental institutions; and, changes in culture which maybe influenced by education and information dissemination. All themanagement proposals need to be clearly defined and costed. One of themore straight-forward and effective changes is to set-up a monitoringprogramme with clear definition as to which agencies are responsible fordata collection, collation, interpretation and implementation ofmanagement measures.


The purpose of monitoring is to compare predicted and actual impacts,particularly if the impacts are either very important or the scale of theimpact cannot be very accurately predicted. The results of monitoring canbe used to manage the environment, particularly to highlight problemsearly so that action can be taken. The range of parameters requiringmonitoring may be broad or narrow and will be dictated by theprediction and mitigation stage of the EIA. Typical areas of concernwhere monitoring is weak are: water quality, both inflow and outflow;stress in sensitive ecosystems; soil fertility, particularly salinizationproblems; water related health hazards; equity of water distributions;groundwater levels.

The use of satellite imagery to monitor changes in land use and thehealth of the land and sea is becoming more common and can prove acost-effective tool, particularly in areas with poor access. Remotelysensed data have the advantage of not being constrained by political andadministrative boundaries. They can be used as one particular overlay ina GIS. However, authorization is needed for their use, which may belinked to national security issues, and may thus be hampered byreluctant governments.

Monitoring should not be seen as an open-ended commitment tocollect data. If the need for monitoring ceases, data collection shouldcease. Conversely, monitoring may reveal the need for more intensivestudy and the institutional infrastructure must be sufficiently flexible toadapt to changing demands. The information obtained from monitoringand management can be extremely useful for future EIAs, making themboth more accurate and more efficient.

The Environmental Management Plan needs to not only include clearrecommendations for action and the procedures for their implementationbut must also define a programme and costs. It must be quite clear exactlyhow management and mitigation methods are phased with projectimplementation and when costs will be incurred. Mitigation andmanagement measures will not be adopted unless they can be shown tobe practicable and good value for money. The plan should also stipulatethat if, during project implementation, major changes are introduced, or ifthe project is aborted, the EIA procedures will be re-started to evaluate theeffect of such actions.

AUDITING

In order to capitalise on the experience and knowledge gained, the laststage of an EIA is to carry out an Environmental Audit some time aftercompletion of the project or implementation of a programme. It willtherefore 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 thetechnical, procedural and decision-making aspects of the EIA. Technicalaspects include: the adequacy of the baseline studies, the accuracy ofpredictions and the suitability of mitigation measures. Procedural aspectsinclude: the efficiency of the procedure, the fairness of the publicinvolvement measures and the degree of coordination of roles andresponsibilities. Decision-making aspects include: the utility of the processfor decision making and the implications for development, (adapted fromSadler in Wathern, 1988). The audit will determine whetherrecommendations and requirements made by the earlier EIA steps wereincorporated successfully into project implementation. Lessons learnt andformally described in an audit can greatly assist in future EIAs and build upthe expertise and efficiency of the concerned institutions.

PUBLIC PARTICIPATION

Projects or programmes have significant impacts on the localpopulation. Whilst the aim is to improve the well being of the population,a lack of understanding of the people and their society may result indevelopment that has considerable negative consequences. Moresignificantly, there may be divergence between national economic interestsand those of the local population. For example, the need to increase localrice production to satisfy increasing consumption in the urban area maydiffer from the needs as perceived by the local farmers. To allow for this,public participation in the planning process is essential. The EIA providesan ideal forum for checking that the affected public have been adequatelyconsulted and their views taken into account in project preparation.

The level of consultation will vary depending on the type of plan orproject. New projects involving resettlement or displacement will require themost extensive public participation. As stated before, the purpose of an EIA isto improve projects and this, to some extent, can only be achieved byinvolving those people directly or indirectly affected. The value ofenvironmental amenities is not absolute and consensus is one way ofestablishing values. Public consultation will reveal new information, improveunderstanding and enable better choices to be made. Without consultation,legitimate issues may not be heard, leading to conflict and unsustainability.

The community should not only be consulted they should be activelyinvolved in environmental matters. The International Union for theConservation of Nature, IUCN promotes the concept of PrimaryEnvironmental Care whereby farmers, for example, with assistance fromextension services, are directly involved in environmental management.The earlier the public are involved, the better. Ideally this will be before adevelopment proposal is fully defined. It is an essential feature of


successful scoping, at which stage feedback will have the maximuminfluence. Openness about uncertainty should be a significant feature ofthis process. As the EIA progresses, public consultation is likely to bedecreased though it is important to disseminate information. Thepublication of the draft Environmental Impact Statement (EIS), willnormally be accompanied by some sort of public hearing that needs to bechaired by a person with good communication skills. He/she may not be amember of the EIA team.

There are no clear rules about how to involve the public and it isimportant that the process remains innovative and flexible. In practice, theviews of people affected by the plan are likely to be heard through someform of representation rather than directly. It is therefore important tounderstand how decisions are made locally and what are the methods ofcommunication, including available government extension services. Therange of groups outside the formal structure with relevant information arelikely to include: technical and scientific societies; Water User Groups;NGOs; experts on local culture; and religious groups. However, it isimportant to find out which groups are under-represented and which onesare responsible for access to natural resources, namely: grazing, water,fishing and forest products. The views of racial minorities, women,religious minorities, political minorities and lower cast groups arecommonly overlooked, (World Bank,1991).

There has been an enormous increase in the number of environmentalNGOs and Green pressure groups throughout the world. Suchorganizations often bring environmental issues to the attention of the localpress. However, this should not deter consultation with such organizationsas the approach to EIA should be open and positive with the aim ofmaking improvements. Relevant NGOs should be identified and theirexperience and technical capacity put to good use.

In some countries, open public meetings are the most commontechnique to enable public participation. However, the sort of open debateengendered at such meetings is often both culturally alien andunacceptable. Alternative techniques must be used. Surveys, workshops,small group meetings and interviews with key groups and individuals areall techniques that may be useful. Tools such as maps, models and posterscan help to illustrate points and improve communication. Whereresettlement is proposed, extensive public participation must be allowedwhich will, at a minimum, involve an experienced anthropologist orsociologist who speaks the local language. He/she can expect to spendmonths, rather than weeks, in the field.

Information dissemination can be achieved using a number ofmechanisms including the broadcasting media, in particular newspapersand radio. Posters and leaflets are also useful and need to be distributed


widely to such locations as schools, clinics, post offices, communitycentres, religious buildings, bus stops, shops etc. The EIA process must beseen to be fair.

The public participation/consultation and information disseminationactivities need to be planned and budgeted. The social scientist teammember should define how and when activities take place and also thestrategy: extensive field work is expensive. It is important to note that publicparticipation activities are often reported as a separate section of the finalEIA. Where experience of managing community involvement is limited,training is highly recommended. Further reading on public participationcan be obtained from: Ahmed L and G K Sammy (1988) and on RapidRural Appraisal from Chambers R (1981). Rapid Rural Appraisal techniquesmay be an appropriate and cost effective method of assessment.

MANAGING UNCERTAINTY

An EIA involves prediction and thus uncertainty is an integral part.There are two types of uncertainty associated with environmental impactassessments: that associated with the process and, that associated withpredictions. With the former the uncertainty is whether the most importantimpacts have been identified or whether recommendations will be actedupon or ignored. For the latter the uncertainty is in the accuracy of thefindings. The main types of uncertainty and the ways in which they can beminimized are discussed by de Jongh in Wathern (1988). They can besummarized as follows:

uncertainty of prediction: this is important at the data collection stageand the final certainty will only be resolved once implementationcommences. Research can reduce the uncertainty;

uncertainty of values: this reflects the approach taken in the EIAprocess. Final certainty will be determined at the time decisions aremade. Improved communications and extensive negotiations shouldreduce this uncertainty;

uncertainty of related decision: this affects the decision makingelement of the EIA process and final certainty will be determined bypost evaluation. Improved coordination will reduce uncertainty.

The importance of very wide consultation cannot be overemphasized inminimizing the risk of missing important impacts. The significance ofimpacts is subjective, but the value judgements required are best arrived atby consensus: public participation and consultation with a wide sector ofthe community will reduce uncertainty. One commonly recurring theme isthe dilemma of whether to place greater value on short-term benefits orlong-term problems.


The accuracy of predictions is dependant on a variety of factors such aslack of data or lack of knowledge. It is important not to focus onpredictions that are relatively easy to calculate at the expense of impactsthat may be far more significant but difficult to analyse. Predictioncapabilities are generally good in the physical and chemical sciences,moderate in ecological sciences and poor in social sciences. Surveys arethe most wide-spread technique for estimating peoples responses andpossible future actions.

The results of the EIA should indicate the level of uncertainty with theuse of confidence limits and probability analyses wherever possible.Sensitivity analysis similar to that used in economic evaluation, could beused if adequate quantifiable data are available. A range of outcomes canbe found by repeating predictions and adjusting key variables.

EIA cannot give a precise picture of the future, much as the EconomicInternal Rate of Return cannot give a precise indication of economicsuccess. EIA enables uncertainty to be managed and, as such, is an aid tobetter decision making. A useful management axiom is to preserveflexibility in the face of uncertainty.

TECHNIQUES

Baseline studies

Baseline studies using available data and local knowledge will berequired for scoping. Once key issues have been identified, the need forfurther in-depth studies can be clearly identified and any additional datacollection initiated. The ICID Check-list will be found useful to define bothcoarse information required for scoping and further baseline studiesrequired for prediction and monitoring. Specialists, preferably with localknowledge, will be needed in each key area identified. They will need todefine further data collection, to ensure that it is efficient and targeted toanswer specific questions, and to quantify impacts. A full year of baselinedata is desirable to capture seasonal effects of many environmentalphenomena. However, to avoid delay in decision making, short-term datamonitoring should be undertaken in parallel with long-term collection toprovide conservative estimates of environmental impacts.

The ICID Check-list

A comprehensive and user-friendly checklist is an invaluable aid forseveral activities of an EIA, particularly scoping and defining baselinestudies. The ICID Environmental Check-List to Identify Environmental


Effects of Irrigation, Drainage and Flood Control Projects (Mock andBolton, 1993) is recommended for use in any irrigation and drainage EIA.The Check-list has been prepared for non-specialists and enables muchtime-consuming work to be carried out in advance of expert input. Itincludes extensive data collection sheets. The collected data can then beused to answer a series of questions to identify major impacts and toidentify shortages of data. A matrix indicates which data are linked towhich questions. Chapter 4 describes the major impacts based on the 8Check-list topics.

The results sheet from the Check-list is reproduced as Table 1. The verysimple layout of the sheet enables an overview of impacts to be presentedclearly which is of enormous value for the scoping process. Similarly, datashortages can be readily seen. The process of using the ICID Check-listmay be repeated at different stages of an EIA with varying levels of detail.Once scoping has been completed, the results sheet may be modified toomit minor topics and to change the horizontal classification to providefurther information about the impacts being assessed. At this point theoutput from the Check-list can be useful as an input to matrices. The ICIDCheck-list is also available as a WINDOWS based software package. Thisenables the rapid production of a report directly from the field study.

Matrices

The major use of matrices is to indicate cause and effect by listingactivities along the horizontal axis and environmental parameters along thevertical axis. In this way the impacts of both individual components ofprojects as well as major alternatives can be compared. The simplestmatrices use a single mark to show whether an impact is predicted or not.However it is easy to increase the information level by changing the sizeof the mark to indicate scale, or by using a variety of symbols to indicatedifferent attributes of the impact. An example of a matrix is given as Table2. The choice of symbols in this example enables the reader to see at aglance whether or not there was an impact and, if so, whether the impactwas beneficial or detrimental, temporary or permanent. Figure 8 is anotherexample of a matrix, in this case used to clearly indicate the importance ofa range of wetland values.

ICOLD has prepared a large and comprehensive matrix for use in EIAsfor dams. The system of symbols for each box shows: whether the impactis beneficial or detrimental; the scale of the impact; the probability ofoccurrence; the time-scale of occurrence; and, whether the design hastaken the impact into account, (ICOLD, 1980). This comprehensiveapproach, however, makes the final output rather difficult to use and amaximum of three criteria is recommended per impact to maintain clarity.Ahmad and Sammy (1985) suggest that the most important criteria are:magnitude, or degree of change; geographical extent; significance; and,


special sensitivity. Significance could be further sub-divided to indicatewhy an impact is significant. For example, it may be because ofirreversibility, economic vulnerability, a threat to rare species etc. Specialsensitivity refers to locally important issues. A series of matrices at allstages of the EIA process can be a particularly effective way of presentinginformation. Each matrix may be used to compare options rated against afew criteria at a time.

The greatest drawback of matrices are that they can only effectivelyillustrate primary impacts. Network diagrams, described below, are auseful and complementary form of illustration to matrices as their mainpurpose is to illustrate higher order impacts and to indicate how impactsare inter-related.

Matrices help to choose between alternatives by consensus. Onemethod is to make pair-wise comparisons. It provides a simple way for agroup of people to compare a large number of options and reduce them toa few choices. First a matrix is drawn with all options listed bothhorizontally and vertically. Each option is then compared with every otherone and a score of 1 assigned to the preferred option or 0.5 to bothoptions if no preference is agreed. An example of such a matrix is given asTable 3. As can be seen, Z is the preferred option.


TABLE 1 - Results sheet for assessing the ICID check-list

1-1 Low flow regime1-2 Flood regime1-3 Operation od dams1-4 Fall of water table1-5 Rise of water table2-1 Solute dispersion2-2 Toxic substances2-3 Organic pollution2-4 Anaerobic effects2-5 Gas emissions3-1 soil salinity3-2 Soil properties3-3 Saline groundwater3-4 Saline drainage3-5 Saline intrusion4-1 Local erosion4-2 Hinterland effect4-3 River morphology4-4 Channel regime4-5 Sedimentation4-6 Estuary erosion5-1 Project lands5-2 Water bodies5-3 Surronding area5-4 Valleys & shores5-5 Wetlands & plains5-6 Rare species5-7 Animal migration5-8 Natural industry6-1 Population change6-2 Income & amenity6-3 Human migration6-4 Resettlement6-5 Womens role6-6 Minority groups6-7 Sites of value6-8 Regional effects6-9 User involvement6-10 Recreation7-1 Water & sanitation7-2 Habitation7-3 Health services7-4 Nutrition7-5 Relocation effect7-6 Disease ecology7-7 Disease hosts7-8 Disease control7-9 Other hazards8-1 Pests & weeds8-2 Animal diseases8-3 Aquatic weeds8-4 Structural damage8-5 Animal imbalancesNumber of crosses (Total = 53)

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TABLE 2 - Ultimate net enviromental impact assessment at a glance, Feitsui reservoir

Features likely Roads Colony Blasting Borrowing Importing Dam Canal Evacuation Soil Reservoir Irrigation Hydro-powerto be affected and construction operation of of construction construction and conservation filling generation

trails materials labour rehabilition andlandscaping

Forestry/Vegetation -1P +2P -1T -1P -1P -1P +4P -3P +3P +1PBirds -2T -2T -1T +3P +4P +2PFisheries -1T -1T -1P +2P +3P +2POther wildlife/land animals -1P -1T -1T -1T -1T -1T -1P +2P +3P +2PSedimentation/erosion -1T -1T -2T +2P +2P +3P -1P -1PFloods -1P -1P +1P +3PHistorical/ culturalMonuments +2P -2PCommunications +3P +2P +1P +2P -1T +2PLand/area development -2P +2P +2P +2P -2P +2P +2P +4P +3PAgriculture +2P -1P -1P -1P -1P +2P -1P +4P +3PFood production +2P +1P -2P -1P -1P +2P -1P +4P +3PPublic revenue/income +2P +2P +3T +2T -2P +2P -2P +4P +3PDrinking water +1P -1T -1T +4P +3P +2PWater quality -1T -1T -2T -2T -1P +1PAir quality -1T -1T -1T -1T +1P +2P +1PClimate +1P +2P +1PGroundwater table +2P +2PIndustrialization +2P +1P +3T +2T +2P +3P +3PHousing +2P +1P +1T +2P -2P +1P +1PEmployment/training +1T +1T +4T +2T +2T +2P +2PHealth and safety -1T -1T -2T -1T -1T -2T +2P +2P +2PScenic views and vistas +1P +2P -1P -2T +2P +2P +3P +4P +2P +2PTourism +2P +2P +3P +3P +1P +2P

Notes: likely effects is symbolized as follows:Mild Considerable high very high

Beneficial +1 +2 +3 +4Detrimental -1 -2 -3 -4T= temporary effect; P=permanent effect

A number of methods have been developed to compare impacts byapplying values to them. The relative importance of impacts, eg wetlandsloss versus rare species loss, or the relative importance of criteria, e.g.economic vulnerability versus probability of occurrence, will depend onthe local environment and priorities. Ranking, and therefore implicitlyvalue, can be determined by using the pair-wise comparison techniquedescribed above, except that, rather than comparing options, criteria arecompared instead. This can enable a series of weightings to be developedwhich will be entirely site-specific and dependant upon the subjectivechoices of those participating in the group which develops the weightings.

A simple example would be to develop weightings for environmentalversus economic acceptability. Thus, in the example illustrated in Figure 2,weightings would have to be developed to determine the preference foreither option B or option C. Is more weight to be given to environmentalor economic criteria?

Reducing information about impacts to a single number should beavoided as it obscures understanding and disguises the subjective nature ofthe analysis. However, it can be useful to compare, for example, thedegree to which different mitigating options are effective in managingwater quality.

Network diagrams

A network diagram is a technique for illustrating how impacts arerelated and what the consequences of impacts are. For example, it may bepossible to fairly accurately predict the impact of increased diversions orhigher irrigation efficiencies on the low flow regime of a river. However,there may be many and far reaching secondary or tertiary consequences ofa change in low flow. These consequences can be illustrated using networkdiagrams. For example, reduced low flows are likely to reduce theproduction of fish which may or may not be of importance depending onthe value (either ecological or economic) of the fish. If fish are animportant component of diet or income, the reduction may lead to a localreduction in the health status, impoverishment and possibly migration.


TABLE 3 - Example of pair-wise comparison

With alternativeCompare alternative W X Y Z Sum

W - 0 0 0.5 0.5X 1 - 1 0 2Y 1 0 - 0 1Z 0.5 1 1 - 2.5

Also, reduced low flow coupled with increased pollution, perhaps as aresult of increased agricultural industry, may further damage the fishpopulation as well as reduce access to safe water.

Table 4 shows an example of a network diagram for a proposed plan toincrease the use of groundwater for irrigation by providing subsidies forsinking deep tube wells. This shows the primary through to quaternaryimpacts, as anticipated at the scoping stage. The main crop in the area isrice. Detailed prediction work following scoping would estimate the level towhich the groundwater would fall and quantify the impacts which, togetherwith economic analysis, would clarify which impacts were most importantand most likely and also determine the most suitable mitigation measures.

Source: (Ahmad and Sammy, 1985)

Overlays

Overlays provide a technique for illustrating the geographical extent ofdifferent environmental impacts. Each overlay is a map of a single impact. Forexample, saline effected areas, deforested areas, limit of a groundwaterpollution plume etc can be analysed and clearly demonstrated to non experts.


FIGURE 2 - Graphical comparison of alternatives. The final choiceofeither option B or option C will depend on the weighting chosen

The original technique used transparencies which is somewhat cumbersome.However, the development of Geographic Information Systems (GIS) canmake this technique particularly suitable for comparing options,pinpointing sensitive zones and proposing different areas or methods ofland management.

Mathematical modelling

Mathematical modelling is one of the most useful tools for predictionwork. It is the natural tool to assess both flow quantities and qualities (egsalt/water balances, pollution transport, changing flood patterns).However, it is essential to use methods with an accuracy which reflectsthe quality of the input data, which may be quite coarse. It should alsobe appreciated that model output is not necessarily an end in itself butmay be an input for assessing the impact of changes in economic, socialand ecological terms. Mathematical modelling was used very effectivelyto study the Hadejia-Jamaare region in Nigeria. In this case themodelling demonstrated the most effective method of operating upstreamreservoirs in order to conserve economically and socially valuable, andecologically important downstream wetlands. Optimal operation wasfound to be considerably different from the traditional method originallyproposed. Under the revised regime the economic returns were alsofound to be higher.


TABLE 4 - Example of network analysis showing of a policy to utilize groundwater by subsiding tubewells

Primary Impacts Secondary impacts Tertiary impacts Quaternary impacts Mitigation

Lowering of groundwater Loss of income & water from Use of poorer quality water Increased health risksin dry season domestic hand pump 1. Ensure that the new DTW either

Income diverted to buy water Decreased income & time hold domestic water locally or feedinto distributary system

Travel to distant source Reduced quality of life Note: Effected group are poorer people

Loss of income & water from Income diverted to buy water Decreased income & time 1. Deepen STWshallow tubewells for irrigation leading to possible food shortage 2. Ensure new DTWs supply STWs in dry season

3. Provide compensation from DTW taxation Crop failure Reduced quality of life

Abandonment of land & migration

Drawdown of surface water bodies Decreased fish capture/fish mortality Loss of protein intake 1. Artificially stock water bodies2. Recharge water bodies from DTW

Note: Fishermen are already poorer than farmers in general

Loss of wetland Loss of wetland flora/fauna migratory 1. Restrict DTW development in vulnerable areasbirds, fish spawning areas Note: Landness & Rural poor are greatest

users of wetlands Loss of wetland products

Reduced navigation possibilities Increased transport costs 1. Increase navigation depth by dredging

Agricultural intensification Increased fertilizer Groudwater contamination Polluted drinking water by nitrate 1. Control fertilizer useby nitrate causes various illness, particularly 2. Educate users of groundwater as well

in babies as fertilizer users babies

Eutrophication of surface water Increased weeds in channels & 1. Remove and control weedsdue to runoff surface water bodies, algal blooms 2. Educate about dangers of algal blooms

Increased pestidice use Groundwater contamination More expensive alternative for 1. Regulate pesticide usedrinking water must be found 2. Encourage rainwater storage

3. Encourage integrated pest management Poisoning of fish & shrimp Reduction in fish catches 4. Subsidize non-persistent pesticides

& protein availability 5. Tax undesirable pesticides6. Educate pesticide users & fish eaters

Reduced income for fishermen

Bioaccumulation of pesticide in man

Increased level of pest & disease Increased pesticide use Bioaccumulation of pesticide in manvectors due to loss of fallow period 1. Vaccinate to prevent epidemics

Increase in animal & human disease Loss of quality of life 2. Encourage alternative cropping patternsdue to vector 3. Educate about disease vectors

Reduced fallow land & grassland Fewer livestock or poor Reduced protein intake & income 1. Develop alternative grazingfor grazing quality livestock for landness groups

Reduced scrubland for fuel wood Alternative sources sought for fuel Income & time spent collecting fuel 1. Develop fuelwood supplies2. Introduce more efficient cookers

Destruction of trees

STW = shallow tubewellsDTW = deep tubewells

Expert advice

Expert advice should be sought for predictions which are inherentlynon-numeric and is particularly suitable for estimating social and culturalimpacts. It should preferably take the form of a consensus of expertopinion. Local experience will provide invaluable insight. Expert opinionsare also likely to be needed to assess the implications of any modellingpredictions. For example, a model could be developed to calculate thearea of wetlands no longer annually flooded due to upstream abstractions.However, the impact on wetland species or the reduction in wetlandproductivity resulting from the reduced flooding may not be so preciselyquantifiable but require a prediction based on expert opinion.

Economic techniques

Economic techniques have been developed to try to value theenvironment and research work is continuing in environmental economics.This is a specialist subject and only a brief introduction is included here.For more detailed information the reader is advised to r

Documents

EIA Procedure for Irrigation Project