Ayat S. Karokaro, South Tapanuli, Indonesia – The death toll from a landslide at the site of a hydropower plant being built in Indonesia's Batang Toru forest has risen to 10, with three people still missing and feared dead, authorities said.
The site, in the north of Sumatra Island, was struck last week with its second deadly landslide in five months, renewing questions over whether the developer has formulated an adequate disaster mitigation plan.
The landslide was triggered April 29 by heavy rains, according to Indonesia's disaster mitigation agency. Using search dogs and excavators to sift through the wreckage, authorities have since recovered the bodies of 10 victims, with three more reported as missing, local disaster mitigation agency head Hotmatua Rambe told AFP.
The China-backed project is already controversial for its location in the only known habitat of the critically endangered Tapanuli orangutan (Pongo tapanuliensis).
An estimated 767 Tapanuli orangutans still live in the Batang Toru forest, divided among three subpopulations, according to a recent study. Researchers say the dam would further fragment their habitat, increasing the risk of extinction.
Deforestation may also exacerbate landslides, already common in Indonesia during the rainy season. In December, at least one worker went missing after a landslide struck.
"Because of the steep topography, if the forest is cleared for a dam, the soil will dissolve, erosion will occur, and landslides become inevitable," Teuku Abdullah Sanny, a geophysicist at the Bandung Institute of Technology (ITB), told Mongabay.
The project developer, PT North Sumatra Hydro Energy (NSHE), could take measures to mitigate landslides, he said, such as by strengthening the slopes through plastic mesh reinforcement.
The area is also prone to earthquakes, with the dam site sitting near a known fault line, a risk acknowledged by the developer. Abdullah said it was necessary to investigate whether the landslide had anything to do with tectonic movements. If a major earthquake happened, he said, a much worse disaster could occur.
Walhi, Indonesia's biggest environmental NGO, unsuccessfully sued the North Sumatra government to revoke the project's environmental permit. A researcher at a local university, Onrizal Onrizal, has said his signature on an environmental impact analysis, known locally as an AMDAL, used by the company to obtain the permit was forged.
In response to the latest landslide, Walhi said the company had failed to formulate an adequate disaster mitigation plan, and reiterated its call for the project to be cancelled.
"The Indonesian government should suspend the AMDAL for the project and conduct an urgent review of the project's viability in terms of risk to worker safety, structural integrity linked to flooding and earthquake risk and the existential threat the dam construction poses to biodiversity," Roy Lumban Gaol, deputy for advocacy and campaigns at Walhi's chapter in North Sumatra, said in a statement.
Company representatives Emmy Hafild and Myrna Soeryo declined to comment.
[This story was reported by Mongabay's Indonesia team and first published here on our Indonesian site on May 5, 2021.]