The Report of the World Commission on Dams
November 16 2000
In April 1997, with support from the World Bank and IUCN-The World Conservation Union, representatives of diverse interests met in Gland, Switzerland, in light of a recent World Bank report, to discuss highly controversial issues associated with large dams. The workshop brought together 39 participants from governments, the private sector, international financial institutions, civil society organisations and affected people. One proposal that came out of the meeting was for all parties to work together in establishing the World Commission on Dams (WCD) with a mandate to:
The WCD began its work in May 1998 under the Chairmanship of Prof. Kader Asmal, who was then South Africa's Minister of Water Affairs and Forestry; its members were chosen to reflect regional diversity, expertise and stakeholder perspectives.
The final report of the World Commission on Dams, Dams and Development: A New Framework for Decision-Making, was released in November 2000.
This overview document provides a highly condensed summary of Dams and Development. We urge readers to refer to the relevant sections in the full report to capture both context and nuances of the findings and recommendations. The full report also includes a detailed list of
acknowledgements that could not be reproduced here, as well as a comment note by Medha Patkar.
The WCD Commissioners
Extensive consultation with all interested groups resulted in invitations to eminent persons to serve as members of the World Commission on Dams.
They were selected on the basis of their wide-ranging backgrounds, views, and the expertise they bring to the debate, with the Secretary General appointed an ex-officio member of the Commission.
The Commissioners collectively were responsible for fulfilling the terms of the WCD mandate. The Commission's work was advisory in nature and not investigatory. Unlike a judicial commission, the WCD was not set up to adjudicate on specific disputes.
Chair Vice Chair
Prof. Kader Asmal Mr. Lakshmi Chand Jain
Minister of Education Chairperson
South Africa Industrial Development Services
Mr. Don Blackmore Ms. Joji Cariño
Chief Executive Tebtebba Foundation
Murray-Darling Basin Philippines
Prof. José Goldemberg Dr. Judy Henderson
Institute of Electronics and Former Chair
Energy Oxfam International
University of São Paulo Australia
Mr. Göran Lindahl Ms. Deborah Moore
President and CEO Senior Advisor
ABB Ltd. Environmental Defense
Sweden United States
Ms. Medha Patkar Prof. Thayer Scudder
Founder Professor of Anthropology
Narmada Bachao Andolan California Institute of
(Struggle to Save the Narmada Technology
River) United States
Dr. Jan Veltrop
Mr. Achim Steiner
WCD Secretary General
International Commission on
(Ex-officio Member of the
The WCD Report - In Brief
The WCD report is a milestone in the evolution of dams as a development option. The debate about dams is a debate about the very meaning, purpose and pathways for achieving development. Through its Global Review of the performance of dams, the Commission presents an integrated assessment of when, how and why dams succeed or fail in meeting development objectives. This provides the rationale for a fundamental shift in options assessment and in the planning and project cycles for water and energy resources development.
The Commission's framework for decision-making is based on five core values - equity, sustainability, efficiency, participatory decision-making and accountability. It proposes:
The Commission's rationale and recommendations offer scope for progress that no single perspective can offer on its own. They will ensure that decision-making on water and energy development:
Dams and Development -- An Introduction
Dams have been built for thousands of years - dams to manage flood waters, to harness water as hydropower, to supply water to drink or for industry, or to irrigate fields. By 1950, governments, or in some countries the private sector, were building increasing numbers of dams as populations increased and national economies grew. At least 45 000 large dams have been built as a response to meet an energy or water need. Today nearly half of the world's rivers have at least one large dam.
As we start the new century, one-third of the countries in the world rely on hydropower for more than half their electricity supply, and large dams generate 19% of electricity overall. Half the world's large dams were built exclusively or primarily for irrigation, and some 30-40% of the 271 million hectares irrigated worldwide rely on dams. Dams have been promoted as an important means of meeting perceived needs for water and energy services and as long-term, strategic investments with the ability to deliver multiple benefits. Some of these additional benefits are typical of all large public infrastructure projects, while others are unique to dams and specific to particular projects.
Regional development, job creation, and fostering an industry base with export capability are most often cited as additional considerations for building large dams. Other goals include creating income from export earnings, either through direct sales of electricity or by selling cash crops or processed products from electricity-intensive industry such as aluminium refining. Clearly, dams can play an important role in meeting people's needs.
But the last 50 years have also highlighted the performance and the social and environmental impacts of large dams. They have fragmented and transformed the world's rivers, while global estimates suggest that 40-80 million people have been displaced by reservoirs.
As the basis for decision-making has become more open, inclusive and transparent in many countries, the decision to build a large dam has been increasingly contested, to the point where the future of large dam-building in many countries is in question.The enormous investments and widespread impacts of large dams have seen conflicts flare up over the siting and impacts of large dams - both those in place and those on the drawing board, making large dams one of the most hotly contested issues in sustainable development today.
Proponents point to the social and economic development demands that dams are intended to meet, such as irrigation, electricity, flood control and water supply. Opponents point to the adverse impacts of dams, such as debt burden, cost overruns, displacement and impoverishment of people, destruction of important ecosystems and fishery resources, and the inequitable sharing of costs and benefits.
With these conflicts and pressures in mind, the World Commission on Dams began its work in May 1998. One of the Commissioners' first points of agreement was that dams are only a means to an end. What is that end? How central are the challenges that large dams set out to meet? And how well can they meet these challenges?
The WCD concluded that the 'end' that any project achieves must be the sustainable improvement of human welfare. This means a significant advance of human development on a basis that is economically viable, socially equitable and environmentally sustainable. If a large dam is the best way to achieve this goal, it deserves support. Where other options offer better solutions, they should be favoured over large dams. Thus the debate around dams challenges views of how societies develop and manage water resources in the broader context of development choices.
After more than two years of intense study, dialogue with those for and against large dams, and reflection, the Commission believes there can no longer be any justifiable doubt about five key points:
The Changing Context
The Commission's overall conclusions about large dams are grounded in a basic understanding about the relationships between water, dams and development. (See Box 1 for the definition of a large dam.) One of the greatest challenges facing the world in this new century is rethinking the management of freshwater resources. A number of global initiatives and reports have documented the dramatic impact of withdrawals from the world's lakes, rivers and underground aquifers. Total annual freshwater withdrawals today are estimated at 3800 cubic kilometres - twice as much as 50 years ago.
Box 1. What is a large dam?
According to the International Commission on Large Dams (ICOLD), a large dam is 15 m or more high (from the foundation).
If dams are between 5-15 metres and have a reservoir volume of more than 3 million cubic metres they are also classified as large dams.
Using this definition, there are more than 45 000 large dams around the world.
The imperative to supply growing populations and economies with water when groundwater is depleted, water quality is declining, and there are increasingly severe limits to surface water extraction has brought sustainable water resources management to the top of the global development agenda. These pressures on water contain a wide range of threats, but they also generate the momentum for new opportunities and policy changes.
During the past few decades, societies have moved from seeing water as a free good to viewing it as a limited natural resource and, more recently, as an economic good and a human right. Thus water is recognised as a scarce natural resource, which gives rise to equity considerations in its allocation.
How much water is required for one more person, or one more urban dweller? Water use per capita varies greatly in different regions of the world. Although what constitutes an appropriate level of domestic water consumption is influenced by climate and culture, several international agencies and experts have proposed 50 litres per person per day as enough to cover basic human requirements for drinking, sanitation, bathing and cooking. In 1990, more than a billion people had less than that. At the same time, households in industrial countries and wealthy city-dwellers in developing countries were using 4-14 times as much.
Dams and Development notes the forecasts of leading analysts who foresee growing competition for water to meet demands for agriculture, industry and drinking water.
During the last century, much of the world turned to dams to help meet escalating demands for water. Indeed, from the 1930s to the 1970s the construction of large dams became - in the eyes of many - synonymous with development and economic progress. Viewed as symbols of modernisation and humanity's ability to control and use nature's resources, dam construction saw a dramatic increase.
This trend reached a peak in the 1970s, when on average two or three new large dams were commissioned each day somewhere in the world. The decline in dam building since then has been equally dramatic, especially in North America and Europe, where most technically attractive sites are already developed.
The top five dam-building countries account for more than three-quarters of all large dams worldwide (see Figure 1), with approximately two-thirds of the world's existing large dams found in developing countries. Hydropower accounts for more than 90% of the total electricity supply in 24 countries, such as Brazil and Norway. Half of the world's large dams are built exclusively for irrigation, and dams are estimated to contribute to 12-16% of world food production. In addition, in at least 75 countries large dams
have been built to control floods. For many nations, dams remain the largest single investment project in the country.
These hydropower, irrigation, water supply and flood control services were widely seen as sufficient to justify the significant investments made in dams, and other benefits were often cited as well. These included the impact of economic prosperity on a region due to multiple cropping, rural electrification and the expansion of physical and social infrastructure such as roads and schools. The benefits were seen as self-evident. When balanced with the construction and operational costs - in economic and financial terms - these benefits were seen to justify dams as the most competitive option.
Figure 1: World population of dams, by country
Source: WCD estimates, based on ICOLD and other sources.
What Is the Debate About?
As noted earlier, the reported returns on the investments made in dams have increasingly been questioned. The notion of costs versus reported benefits emerged as a public concern, given growing experience and knowledge about the performance and consequences of dams. Driven by research and information on the impacts of dams on people, river basins and ecosystems, as well as data on economic performance, opposition began to grow. During the early stages of this process, debate and controversy focused on specific dams and their local impacts. But gradually these locally driven conflicts began to evolve into a more general and ultimately a global debate about dams.
The issues surrounding dams are the same issues that surround water, and how water-related decisions are made, as well as how development effectiveness is assessed. There is little public controversy about the choice between an embankment dam or a gravity dam, or about whether to use earth, concrete or rock-fill. The problems all relate to what the dam will do to river flow and to rights of access to water and river resources; to whether the dam will uproot existing settlements, disrupt the culture and sources of livelihood of local communities, or deplete or degrade environmental resources; and to whether the dam is the best economic investment of public funds and resources.
The debate is partly about what occurred in the past and continues to occur today, and partly about what may unfold in the future if more dams are built. In some countries, it is driven primarily by specific social or environmental concerns; in others, by broader development considerations. In the United States, where the rate of decommissioning is greater than the rate of construction of new large dams, the debate is perhaps as intense as - but qualitatively different from - the debate in India, which along with China is now building the most dams.
The two principal poles in the debate illustrate the range of views on past experience with large dams. One perspective focuses on the gap between the promised benefits of a dam and the actual outcomes. The other view looks at the challenges of water and energy development from a perspective of 'nation building' and resource allocation. To proponents, the answer to any questions about past performance is self-evident, as they maintain that dams have generally performed well as an integral part of water and energy resource development strategies in over 140 nations and, with exceptions, have provided an indispensable range of water and energy services.
Opponents contend that better, cheaper, more benign options for meeting water and energy needs exist and have been frequently ignored, from small-scale, decentralised water supply and electricity options to large-scale end-use efficiency and demand-side management options. Dams, it is argued, have often been selected over other options that may meet water or energy goals at lower cost or that may offer development benefits that are more sustainable and more equitable.
Although there may be agreement on such issues as the need to take environmental and social costs of dams more seriously and to consult systematically with affected people, deep fault lines still separate critics and proponents on a number of financial, economic, social and environmental issues. Among the most intractable are:
The decision to build a large dam today is rarely only a local or national one. The debate has been transformed from a local process of assessing costs and benefits to one in which dams in general are the focus of a global debate about development strategies and choices.
What Did the WCD Global Review of Large Dams Find?
To fulfil its mandate to review the development effectiveness of large dams and assess alternatives for water resources and energy development, the Commission undertook eight detailed case studies of large dams and prepared country reviews for India and China plus a briefing paper on Russia and the Newly Independent States. (See Box 2 for a list of the case study dams.)
A survey of 125 large dams was also developed, along with 17 thematic reviews on social, environmental and economic issues; on alternatives to dams; and on governance and institutional processes. There were also 947 submissions and presentations at four regional consultations. All these inputs formed the core of the WCD Knowledge Base that served to inform the Commission on the main issues surrounding dams and their alternatives.
Box 2. WCD Case Study dams
Aslantas dam, Ceyhan River Basin, Turkey
Glomma-Lågen Basin, Norway
Grand Coulee dam, Columbia River, United States/Canada Kariba dam, Zambezi River, Zambia/Zimbabwe
Pak Mun dam, Mun-Mekong River Basin, Thailand Tarbela dam, Indus River Basin, Pakistan
Tucuruí dam, Tocantins River, Brazil
Gariep and Vanderkloof dams, Orange River, South Africa (pilot study)
The Global Review had three components:
The WCD's evaluation of performance was based on the targets set for large dams by their proponents - the criteria that provided the basis for government approval and financing. The Commission's analysis gave particular attention to understanding why, how and where dams did not achieve their intended outcome, or indeed produced unanticipated outcomes. An integral part of this research involved documenting good practices that have emerged as a response to past shortcomings and difficulties. Presenting this analysis does not overlook the substantial benefits derived from dams, but rather responds to the question of why some dams achieve their goals while others fail.
Technical, Financial and Economic Performance
The degree to which large dams in the WCD Knowledge Base have delivered services and net benefits as planned varied substantially from one project to the next, with a considerable portion falling short of physical and economic targets. In spite of this, the services produced by dams are considerable, as noted earlier. Irrespective of performance against targets, the Knowledge Base also confirmed the longevity of large dams, with many continuing to generate benefits after 30-40 years of operation.
A sectoral review of technical, financial and economic performance of dams in the Knowledge Base in terms of planned versus actual performance suggested the following:
The review of performance suggested two further findings:
The review also examined factors related to the physical sustainability of large dams and their benefits and confirmed that:
severe, long-term and often permanent impacts on land, agriculture and livelihoods where rehabilitation is not undertaken
Using the information on the performance of large dams collected in the WCD Knowledge Base, the Commission's report shows that there is considerable scope for improving the selection of projects and the operation of existing large dams and their associated infrastructure. Considering the enormous capital invested in large dams, it is surprising that substantive evaluations of project performance are few in number, narrow in scope and poorly integrated across impact categories and scales.
Ecosystems and Large Dams
The generic nature of the impacts of large dams on ecosystems, biodiversity and downstream livelihoods is increasingly well known. From the WCD Knowledge Base it is clear that large dams have led to:
On balance, the ecosystem impacts are more negative than positive and they have led, in many cases, to significant and irreversible loss of species and ecosystems. In some cases, however, enhancement of ecosystem values does occur, through the creation of new wetland habitat and the fishing and recreational opportunities provided by new reservoirs.
The Commission found that reservoirs sampled so far by scientists all emit greenhouse gases, as do natural lakes, due to the rotting of vegetation and carbon inflows from the catchment. The scale of such emissions is highly variable. Preliminary data from a Case Study hydropower dam in Brazil show that the gross level of these emissions is significant, relative to emissions from equivalent thermal power plants.
However, in other reservoirs studied (notably those in boreal zones), gross emissions of greenhouse gases are significantly lower than the thermal alternative. A full comparison would require measurements of the emissions from natural pre-impoundment habitats. More research is needed on a case-by-case basis to demonstrate the capacity of hydropower to offset climate change.
Efforts to date to counter the ecosystem impacts of large dams have met with limited success due to the lack of attention to anticipating and avoiding such impacts, the poor quality and uncertainty of predictions, the difficulty of coping with all impacts, and the only partial implementation and success of mitigation measures. More specifically:
Given the limited success of traditional mitigation measures, increased attention through legislation is now given to avoidance or minimisation of ecological impacts through setting aside particular river segments or basins in their natural state and through the selection of alternative projects, sites or designs. In addition, governments are experimenting with a 'compensatory' approach, offsetting the loss of ecosystems and biodiversity caused by a large dam through investment in conservation and regeneration measures and through protection of other threatened sites of equivalent ecological value.
Finally, in a number of industrialised countries, but particularly in the United States, ecosystem restoration is being implemented as a result of the decommissioning of large and small dams.
People and Large Dams
In terms of the social impacts of dams, the Commission found that the negative effects were frequently neither adequately assessed nor accounted for. The range of these impacts is substantial, including on the lives, livelihoods and health of the affected communities dependent on the riverine environment:
livelihoods and the future productivity of their resources has been put at risk
In sum, the Knowledge Base demonstrated a generalised lack of commitment or lack of capacity to cope with displacement. In addition, large dams in the Knowledge Base have also had significant adverse effects on cultural heritage through the loss of cultural resources of local communities and the submergence and degradation of plant and animal remains, burial sites and archaeological monuments.
The Knowledge Base indicated that the poor, other vulnerable groups and future generations are likely to bear a disproportionate share of the social and environmental costs of large dam projects without gaining a commensurate share of the economic benefits:
Where such inequities exist in the distribution of the costs and benefits, the Global Review emphasises that the 'balance-sheet' approach to adding up the costs and benefits is increasingly seen as unacceptable on equity grounds and as a poor means of choosing the 'best' projects. In any event, the true economic profitability of large dam projects remains elusive, as the environmental and social costs of large dams were poorly accounted for in economic terms.
More to the point, failures to account adequately for these impacts and to fulfil commitments that were made have led to the impoverishment and suffering of millions, giving rise to growing opposition to dams by affected communities worldwide. Innovative examples of processes for making reparations and sharing project benefits are emerging that provide hope that past injustices can be remedied and future ones avoided.
Options for Water and Energy Resources Development
The Global Review examined the options for meeting energy, water and food needs in today's circumstances and the barriers and enabling conditions that determine choice or adoption of particular options. Many options currently exist - including demand-side management (DSM), supply efficiency, and new supply options. These can all improve or expand water and energy services and meet evolving development needs across all segments of society. Viewing these options in an integrated fashion, rather than for individual sectors, suggested the following general findings and lessons:
The ability of various options to meet existing and future needs or to replace conventional supplies depends on the specific context, but in general they offer significant potential, individually and collectively.
Decision-Making, Planning and Compliance
As a development choice, large dams often became a focal point for the interests of politicians, dominant and centralised government agencies, international financing agencies and the dam-building industry.
Involvement from civil society varied with the degree of debate and open political discourse in a country. However, dams in the WCD Knowledge Base reveal a generalised failure to recognise affected people as partners in the planning process, with rights, and to empower them to participate in the process.
Foreign assistance has accounted for less than 15% of total funding for dams in developing countries. Still, the funds provided - more than $4 billion per year during the peak of lending in 1975-84 -played an important role in promoting and financing large dams in countries building only a few dams. These countries have often been vulnerable to conflicts between the interests of governments, donors and industry involved in foreign assistance programmes, on the one hand, and improved development outcomes for rural people, particularly the poor, on the other hand.
To a lesser extent this assistance has supported larger countries seeking to build many dams (including China, India and Brazil), primarily through the provision of finance for dam-building programmes. In shared river basins, the lack of agreements on water use is an increasing concern and cause for tension, particularly as demands grow and unilateral decisions by one country to build large dams alter water flows within a basin, with significant consequences for other riparian States.
Evaluation of the planning and project cycle for large dams revealed a series of limitations, risks and failures in the manner in which these facilities have been planned, operated and evaluated:
The net effect of these difficulties is that once a proposed dam project has passed preliminary technical and economic feasibility tests and attracted interest from government, external financing agencies or political interests, the momentum behind the project often prevails over further assessments.
As a result, many dams were not built based on a comprehensive assessment and evaluation of the technical, financial and economic criteria applicable at the time, much less the social and environmental criteria that apply in today's context. That many such projects have not met standards applicable in either context is therefore not surprising, but nonetheless cause for concern.
Conflicts over dams stem also from the failure of dam proponents and financing agencies to fulfil commitments made, observe statutory regulations and abide by internal guidelines. In some cases, the opportunity for corruption provided by dams as large-scale infrastructure projects further distorted decision-making, planning and implementation. Whereas substantial improvements in policies, legal requirements and assessment guidelines have occurred, particularly in the 1990s, it appears that business is often conducted as usual when it comes to actual planning and decision-making. Moreover, where substantial differences arise between proponents and those potentially affected, efforts to modify plans and decisions often must resort to legal or other action outside the normal planning process. Regional Consultations held by the Commission underscored that past conflicts remain largely unresolved for a number of reasons, including poor experience with appeals, dispute resolution and recourse mechanisms.
Throughout the Global Review recent examples and illustrations of good practice are presented that form the basis of the Commission's optimism that these barriers are surmountable, and that these difficulties are not inevitable. As a means of reducing negative impacts and conflicts, these experiences indicate that there are opportunities, and indeed a responsibility, to: