The president of Tanzania has inaugurated a huge controversial hydroelectric dam project in a wildlife reserve at the centre of warnings over rhino and elephant populations.

Conservation groups have opposed the Stiegler’s Gorge project in the Selous Game Reserve, the country’s largest wildlife area, which Unesco says has one of the most significant concentrations of elephants and black rhinos.

President John Magufuli called the project “the start of economic liberation”, saying the reserve – which is also a haven for cheetahs and giraffes – has been considered a potential energy source for decades.

Only one in 10 households in in the East African nation has access to the national grid and electricity prices are high.

“Beginning today, this will indicate that Tanzania is an independent country... and not a poor country,” Mr Magufuli said.

Conservation success for the Gorongosa National Park in Mozambique Show all 8 1 /8 Conservation success for the Gorongosa National Park in Mozambique Conservation success for the Gorongosa National Park in Mozambique Tourists observe elephants Left devastated by Mozambique's civil war, Gorongosa National Park is now thriving Bob Poole / Gorongosa National Park Conservation success for the Gorongosa National Park in Mozambique Waterbuck graze in the open floodplains A restoration project with government backing has battled poachers who were depleting the already slim animal populations AFP/Getty Conservation success for the Gorongosa National Park in Mozambique Hippos take a dip In 2008, there were around 10,000 large animals in Gorongosa; today there are over 100,000 J Da Silva / Gorongosa National Park Conservation success for the Gorongosa National Park in Mozambique Wild dogs in Gorongosa National Park Tourism is an important part of the restoration project Gorongosa National Park Conservation success for the Gorongosa National Park in Mozambique Waterbuck on the savannah Tourists create jobs for locals, expanding the conservation workforce, and safaris in Gorongosa are used to educate visitors about the project Getty Conservation success for the Gorongosa National Park in Mozambique A lioness The civil war killed 95% of Gorongosa's lion population, today there are 104 lions who are monitored by conservationists Ticky Rosa / Gorongosa National Park Conservation success for the Gorongosa National Park in Mozambique Sunset over the Gorongosa National Park Sunset over the National Park Gorongosa in the center of Mozambique. istock Getty Conservation success for the Gorongosa National Park in Mozambique Tourists in Gorongosa National Park Tourists in Gorongosa National Park Credit: Bob Poole / Gorongosa National Park Bob Poole / Gorongosa National Park

The scheme, expected to take three years to finish, will mean chopping down 2.6 million trees to flood an area covering about 1,200sq km, including the habitats of the site’s last remaining black rhinos.

The dam would be 130 metres high and stretch 700 meters across the Stiegler Canyon at the Rufiji River, in a Unesco World Heritage Site that is one of Africa’s largest protected areas and relatively undisturbed by humans.

The president said he hoped the project would boost industrial development.

“It’s time to benefit from our national resources,” he said.

Opponents of the project say it could also threaten the livelihoods of tens of thousands of people downstream, who depend on the river for agriculture and fisheries.

Last month the IUCN, together with Unesco’s World Heritage Centre, called for an immediate halt to logging and other preparations, warning of “irreversible damage” if it went ahead.

An independent review commissioned by IUCN highlighted the “inadequacy” of the environmental impact assessment.

“It would cut the heart out of the Selous reserve, with catastrophic impacts on the site’s wildlife and habitats,” said Peter Shadie, of the IUCN’s World Heritage Programme.

Mr Magufuli (centre) at the ceremony with a 3D model of the project (REUTERS)

After the inauguration, the Worldwide Fund for Nature said the game reserve was of “extraordinary importance” and urged Tanzania’s government to consider “less harmful energy alternatives”.

But earlier this month, Mr Magufuli downplayed fears for the environment, saying that by providing energy, the dam would deter locals from felling trees for fuel.

“I want to reassure everyone this project in fact aims to promote the environment,” Magufuli said, Business Day reported.

“Also, it’s just a small part of the reserve – just 3 per cent of the total area.”

The president said the dam would not only meet national electricity needs but would also provide power to export.

The International Monetary Fund predicts the economy of Tanzania, will grow by 4 per cent this year, down from 6.6 per cent last year.

The Elephant Protection Initiative said the fact that a leading wildlife country was “prepared to contemplate drowning their natural crown jewels in pursuit of megawatts must serve as a serious wake-up call to everyone in conservation”.

“We need to make the case urgently that wildlife conservation can not only pay for itself, but that it is often the best way for the human populations who live around it to realise their legitimate aspirations for development and prosperity.

“Destroying habitat may present the illusion of short-term economic gain, but in the long run is counterproductive, not just for wildlife of course, but also people and economies.”