Camilla Zanzanaini/Bioversity International

A new report on the effectiveness of large dams (Ansar et al) gained a lot of international press recently. The CGIAR Research Program on Water, Land and Ecosystems and its partners  are working extensively around water and energy related issues and large dams feature prominently in our work particularly in the Mekong.

The new report asked the question “Should we build more large dams”.  In celebration of World Water Day (March 22), we asked this to a number of different thought leaders to stimulate discussion and dialogue around this issue.

See below for brief excerpts from each of our respondents.  


Akosombo Dam, Ghana. Photo: Camilla Zanzanaini/Bioversity International Akosombo Dam, Ghana. Photo: Camilla Zanzanaini/Bioversity International


We also want to hear from you. Please provide your own thoughts and ideas in the comment section below.


To a large extend I agree with Fred Pearce. I made a study in Peru about the effect of a large scale dam + a river diversion in the livelihood of poor peasants (depending of that river). Here the results in short:
- overrun investment, impossible to recover it.
- Although it gained some new agricultural lands, it also salinized fertile agriucltural lands (downstream)
- It dried water sources of many rural communities
- The irrigation of one hectare of the new agricultural land, implies the drying of 3 hectares of the fertile land of poor peasants.
- Ecological disaster downstream the diverted river
- Migration of poor peasants and sell of their wage labour in the newly subsidized agricultural lands, etc.

Are you interested in knowing more about this study?, here the link: , for the full study see my thesis: The ethno-politics of water security. Contestation of ethnicity and gender in strategies to control water in the Andes of Peru. Doctoral Thesis, Wageningen University. The Netherlands.

NO, we should not be building more dams. We need to find ways that do not poison our water systems to create our energy..these megadams are NOT green!

Save Muskrat Falls, Labrador, Canada from being dammed!!

Search us on facebook: Friends of Grand River/Mistashipu

Even conservative estimates indicate that the population of Pakistan will grow to 208 million by the year 2025. About 50 per cent of the population will be living in the urban areas thus exerting additional pressure on the already strained existing facilities. Situation at present is very precarious due to our typical lethargic policies. Our political leadership must wake up before it is too late.

An ambitious study conducted by Carnegie Corporation of New York USA projected Pakistan as severely water scarce country in South Asia in 2025. Pakistan will require 335 billion cubic meters of water whereas it will have no more than 233 billion cubic meters available. We need to appeal to the government and all non-government organisations to come forward and formulate united efforts to put an end to shortfall of 102 billion cubic meters.

In this connection, dynamic leadership promotes and formulates united efforts to construct Dams and reservoir in the country to put an end to shortfall of 102 billion cubic meters. If water sources were not developed, a human and economic Cates trophy will surely occur. That is why a dynamic leadership is needed for Pakistan to uplift water resources and resolve other water related issues on emergency basis. To achieve this target, we should focus on the water challenges which call for Strategic Planning & Management (SPM) across all sectors of the national economy as well as our political horizon. National water action agenda needs to be drawn up through active Youth, Gender and other stake-holder’s participation. In this connection, we should work in partnership with all parties including local communities, private sector, NGOs, and other stakeholders. Participation of Youth and Gender is a sustainable dividend in long run to change mindset of society towards emerging issues in water sector.

Without water humans and other living organisms die, farmers cannot grow crops, businesses cannot operate and environment cannot get better rather the whole human life comes to standstill without water, Ecosystem is completely threatened in the absence of water. Blue Revolution is the only way out in the world.

Sustainability is not only about what happens on the landscape to natural resources but also about what happens in the hearts and minds of citizens. We believe the best way to sustain the forest and water resources is to sustain the people who take care of it, if we fail to make this decision on time, we will face unbearable consequences in the time to come and bring the whole humanity to the stone age of poverty and extreme hunger, this is what nobody would like, particularly the committed and true leadership of the world. The vision of any idea including this one, can only be acknowledge by action and not by words, this is the reality which needs to be approached on time. Thank you for your paying your kind attention to this important issue.

According to the definition of International Commission on Large Dams (ICOLD), there are only 40 Dams and reservoirs in Pakistan despite a good Irrigation System. It is shocking information for the elites and political leadership of the country to know that Pakistan has built only 40 Dams and reservoirs in last fifty-five years where as there is an immense potential for building many Dams along North, South and West-East natural slopes in the country. The Dams, particularly the large Dams continue to be planned, constructed and operated with the aim of achieving important socio-economic development objectives. Their potential to alleviate poverty can, and in many cases will continue significantly to the improvement of human life. Benefit of the Dams is not disputed, but it is the uneven distribution of benefits including the poverty alleviation programs that need to be addressed in the planning, construction and operation of Dams. Employment opportunities and other economic related activities would be identified in the early stage and managed as an integral part of the Dam designing, construction and operation.
All stakeholders shall be given guarantees that their interest should be protected in the sense of ownership and equal distribution of benefits to all. The protection and promotion of stakeholders’ interest in the context of Dam projects can only be ensured if all potentially effected communities have an opportunity to gain economic benefits from the after effects of the large Dams.
Such an alarming situation increases the task of national and international organisations pertaining to water many fold. In the wake of the devolved government, “Blue Revolution and Dams for Development Partnership or Blue Revolution and Dams for Development Taskforce” can play a very important role as their root are embedded in the community and has linkages with national and international organisations. Being local, gender balanced, and fully aware of local customs and traditions with no language barriers it can easily bring awareness and educate the local communities about the optimised use of water.

If the question is how to create more water storage in the most efficient, least cost way, with zero environmental consequences, then the answer is AQUIFER STORAGE. Managed aquifer recharge (MAR) technology in general, or aquifer storage recovery (ASR) technology in particular, have proven economic and water management success throughout the world. MAR solutions should always be thoroughly explored for feasibility before considering surface storage. In addition to all the environmental and water conservation benefits, MAR offers the incredible benefit of scaleability with almost immediate operation potential from initial investment and the option to expand projects incrementally as demand increases or financing becomes available. The US based American Ground Water Trust has convened over 30 conferences since 1998 that have focused on hydrologic, geologic, economic, engineering, legal, environmental and political aspects of MAR.

We should build more dam particularly in developing countries in Africa, Latin America and Asia. Dam can not only produce hydroelectricity but also provide important services including flood control, drought alleviation, water supply, and navigation. In the United States, only 2,066 (2%) out of 82,642 dams of all size are primarily used for hydropower. Large dams can protect densely populated countries from serious flood damage. The flood conditions downstream the Three Groges Dam in 1998 and 2012 are totally different with the flood storage of the TGD. In the era for developing new energy to adapt to climate change, hydropower can contribute to the stability of the electrical system by providing the full range of ancillary services required for the high penetration of variable renewable energy sources, such as wind and solar. Of course dam will result adverse environmental and social impacts including natural flow alternation, fragment of habitat, disruption of fish migration and resettlement. So the scientists, engineers and sociologist have been working for decades to assess the impacts and implement mitigation measures to avoid, mitigate and compensate these adverse impacts. It is easy to say no but is quite difficult to give solution or constructive suggestion. If we can find a solution which is better than dam in the aspect of electricity production and water operation, we won't build more dam. But who can?

Definitely, the fossil fuel lobby hates large dams !
The study by Ansar et al. completely ignores the climate change problem. They promote fast built fossil fuels plants instead . Their statistics are biaised since they forget that the main use of large dams is not power production but food production! (storing water to feed irrigation systems).
I think your panel of commentators is not equilibrated at all since they all share a common hatred against dams. IHA has published an answer here : and ICOLD will soon publish a more complete one.

the interrelations among water, energy, food, climate change, poverty, social and economical development etc etc are well known. Large dams can be the proper answer to several problems only if their design and management enter into a regional masterplan. The impact of large infrastructures, like large dams, is very high but also the benefits can be very important, such as flood control, water reservoirs for dry period to assure agriculture activities and also energy production. As other contributors said, it is impossible to give a generic answer. Each case must be considered independently. The aspects to be taken into account are several and goes from the purely technical ones to the ones related to transboundary management so that usually these large infrastructures affect international water courses. I am not negative at all about large dams a priori but I am convinced that for the success of the investment and the satisfaction of the down stream river side population, several fundamental aspects have to be taken into consideration. Among these: the regional impact; the set up of an international authority (such a basin authority) for the management of the new hydraulic regime according to hydrologic forecast and the needs of all the users. Not last, such large dams require highly specialised personnel for the real time regulation, especially in case of extreme events. So, the design and the construction of large dams must be always associated to advanced training for the benefit of the hydrografic district affected by the dam.

It is sad to see the CGIAR system being used to present thinly disguised propaganda as science.

The study of dam cited costs carefully avoided comparison with other sectors which would reveal that most public finance projects suffer similar challenges. Even in the private sector, many IT projects, for instance, fail to deliver anything close to the benefits initially promoted. Yet they form the basis of many successful businesses.

The notion that aquifers can provide equivalent storage to large dams is fantasy in many parts of the world, including much of Africa.

The fact that the only technology to store energy at national grid scale depends on dams and hydropower is conveniently ignored, thus carefully avoiding the critical role that flexible hydropower will play in the power systems of the future.

I could go on but see no point and only contribute to ensure that it is clear that the quality of work presented by no means represents ether a consensus or good science.

I endorse fully Mike Muller!
Suffice to say that enough damage has been done already by an agenda 'motivated' to kill dams (and storage that went along with it) in almost many parts of the world. But for this new wave that emerged since the last two decades, the world was moving slowly to create storage (large and small) wherever this was feasible. This action was decelerated so much with negative propoganda on dams so much that the world is facing with worse water security (and of course, energy, food and environmental security - in the face of GCC). To argue that science backs the agenda of 'no dams' by floating a topic of the sort by any reputed Institution and try to work towards goals that would result in widening gap in water availability and needs to secure food, energy and water in many parts of the world (which remained dormant in the last century in water harnessing) is but unfortunate! Is it an extension of the committed agenda of WCD in a different style?

If research is to go by, there is something to believe that construction of large dams must either be revisited or seized altogether.

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