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Two Hydropower Giants and Ecological Impact

Two Hydropower Giants and Ecological Impact

Two Chinese hydropower giants is credited with the construction of over half of the world’s dams and these dams have been causing irreversible damage to ecologically sensitive regions and rarest species, said a new report by International Rivers, a non-profit organisation.

The report – Advancing Ecological Civilization – was launched on October 14, 2021 during the biennial conference of the global Convention on Biological Diversity treaty.

The International Rivers say that PowerChina and China Three Gorges, the two dam-builders, lacked clearly defined no-go policies to exclude problematic projects that harmed the environment.

In the report, the authors looked at six projects each from these parent companies and found that the projects affected protected areas that are home to many a biodiversity. It said that the dams accelerated biodiversity loss that harmed the interests of the indigenous peoples and affected critically endangered species.

The report mentions that hydropower dams have had a particularly significant impact on global biodiversity and the ecosystem services that it provides. “They have been found to be a key culprit in the 84 per cent loss of freshwater species experienced since 1970. Dams and associated infrastructure such as roads and transmission lines have taken a significant ecological toll on terrestrial biodiversity as well, both directly by submerging or fragmenting habitats, as well as indirectly by bringing people and human settlements into previously inaccessible areas,” the report noted.  It pointed out that the dams also have a significant human cost.


Protected areas are not spared from dam construction, including in UNESCO World Heritage sites.

The report notes that over 500 dams under construction/ planned across the world are going to be built in protected areas. It says that half of the 12 projects analysed would directly impact protected areas that harbour considerable biodiversity, including national parks, Ramsar sites and even UNESCO World Heritage sites.

The report cites that PowerChina’s subsidiary Sinohydro is the primary subcontractor on the Julius Nyerere dam in Tanzania, which is under construction in the middle of Selous Game Reserve, a UNESCO World Heritage Site. The report notes that this construction would submerge habitats of some of Africa’s most iconic and endangered species like black rhinoceros. Moreover, the construction of 120 km of roads into the heart of the reserve will exacerbate the already persistent problem of poaching, which had nearly wiped out the reserve’s elephant and rhinoceros populations.

In its recommendation, the authors want companies to adopt an explicit policy prohibiting dams that are constructed in or have significant impacts on protected areas, including UNESCO World Heritage sites.

Growing number of dams, impact critically endangered great ape populations

In the report, the authors find that five of seven great ape species are critically endangered because of dam construction. According to one estimate, “by 2030, fewer than ten per cent of ape ranges in Africa and only about one per cent of those in Asia will remain untouched by infrastructure development and the associated habitat disturbance.

One of the worrying examples pinpointed in the report is that of the Batang Toru dam, a highly controversial project in North Sumatra, Indonesia. PowerChina subsidiary Sinohydro is indulged in the construction despite urgent global calls to halt the construction after orangutans local to the project site were discovered to be in danger. The Tapanuli orang-utan are already endangered. Conservationists and environmentalists warn that Batang Toru dam alone could lead to their extinction within decades.

The report mentions that companies should adopt a policy prohibiting projects that will entail irreversible impacts on endangered species, particularly apes. It also called for withdrawal of the company from Batang Toru and Koukoutamba dams immediately.

Dams planned on free-flowing rivers are of particular concern, including to biodiversity

The International Rivers pointed out that the first dam constructed on a previously free-flowing river has a disproportionately large impact on freshwater ecosystems. In some cases, 40 per cent of a river’s aquatic species can be lost as a result. Of the 177 largest rivers in the world, only one-third are free flowing, and just 21 rivers longer than 1000 kilometres retain an unobstructed connection to the sea.

The report said that the greater concern was that of the Mong Ton dam on the Salween River in Myanmar. The Salween, also called the Nu River upstream in China, is the longest undammed river in mainland Southeast Asia and supports the livelihoods of over ten million people, sustaining the rich fisheries and fertile farmland central to the lives of indigenous and ethnic minority communities living along its banks.

The Companies should forego projects proposed on a free-flowing river or the mainstream of a major river, the report recommended.

Human cost of biodiversity loss, particularly for indigenous peoples

The report mentions that dams could adversely affect indigenous cultures and identities.

The São Manoel dam located on Brazil’s Teles Pires River in the Tapajós Basin, one of eight areas of Amazonian biological endemism is slated to be dangerous to indigenous people including the Munduruku, Kayabi and Apiaká. They have long opposed hydropower development on their lands and on the stretch of river that sustains freshwater species and other species that are integral to their lives, livelihoods and culture.

The report calls for adopting a requirement to secure the Free, Prior and Informed Consent (FPIC) of communities before becoming involved in projects that may impact indigenous peoples and their territories

Pronounced impacts from the cumulative impacts of multiple dams on a river    

The construction of dams could alter the flow of rivers, which could have severe ecological impact. These impacts are mainly pronounced on freshwater species that face multiple barriers and find their habitats confined to a short stretch of river, or experience significant fluctuations in river flows that disrupt fish breeding grounds and aquatic biota that are critical to the food chain.

The authors of the report want a first hold a cumulative impact assessments for dams on rivers with multiple dams to fully assess impacts, and that robust mitigation measures are in place to address them.

Company policies regarding biodiversity and due diligence fall well below international standards.

The Advancing Ecological Civilization calls for adopting and implementing due diligence procedures with clear bottom lines aligned to international standards.



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