x Abu Dhabi, UAESaturday 22 July 2017

Hunza Valley inches towards flood

Around 13,000 residents are ordered to evacuate as a glacier-fed lake rises steadily to the edge of a dam.

Residents in Pakistan's Hunza Valley are at risk from a possible flash flood.
Residents in Pakistan's Hunza Valley are at risk from a possible flash flood.

KARIMABAD, Pakistan // Hanif, a sergeant in the Pakistani army's corps of engineers, squatted at the edge of a road overlooking a massive grey-black mound of landslide debris. It was this debris that had on January 4 buried alive 19 residents of Ata-abad, a riverside settlement in the northern Hunza Valley.

"We've been here, working with the Chinese, for nearly five months, when there was still snow in the valley," he said, untying a cloth containing a modest lunch of chapattis and congealed lentils. Before he could tuck in, however, Tariq, another sergeant, dragged him back to the arduous task of excavating a spillway through the 70-metre-high mound. The landslide is holding back a 20km glacial lake that has been rising by a metre per day since the onset of summer at the start of May.

Yesterday, excavation of the dam stopped and the countdown to the possible collapse of the spillway began. "Oye! Why isn't that machine back at work yet?" Tariq shouted, pointing to a bright yellow Chinese earth-moving machine that stuck out in the moonscape-like scene. "They're waiting for fuel," Hanif shouted back. About 30,000 litres of diesel had finally arrived after landslides caused by the rains on Thursday and Friday blocked the road linking the Ata-abad area to the regional capital of Gilgit. The seasonal acceleration in the melting rate of the six glaciers feeding the huge body of water has injected a renewed sense of urgency to the army engineers' efforts.

By Saturday, the lake was hardly six metres from reaching the lip of the dam, the critical point at which it would become clear whether the dam will hold, crumble in stages, or collapse, a very unlikely but terrifying worst-case scenario, Pakistani engineers and international experts have agreed. Hanif frowned with frustration. "Every time we excavate, more debris slides down and fills the spillway," he said in an interview. "All we can do is to keep excavating and hope it reduces at least some of the force of the [flash] flood, when it comes."

Authorities in the Gilgit-Baltistan region have ordered 13,000 residents of downstream riverside settlements to evacuate to schools and healthcare clinics more than 30 metres above the riverbed by Thursday. The impending crisis point has attracted a bevy of helicopter-borne dignitaries from Islamabad, the federal capital, about 720km to the south. The latest, on Saturday, was Arbab Alamgir, the federal minister for communications, who held court in a tent at the base camp of the Frontier Works Organisation, the army's go-anywhere-anytime road-building engineers.

Accompanying him was Chaudhry Altaf Hussain, the chairman of the National Highway Authority, who stepped outside to view the gradient between the top of the dam and the empty riverbed. He agreed with a prediction of Nespak, a state engineering consultancy, that no more than 70 per cent of the dam would collapse in one go, but disagreed with its conclusion that a flash flood would not exceed 30 metres, which was the assumption made in evacuation plans for downstream communities.

"Obviously, the water has to attain the level of the riverbed below, so the flood could be as high as 40 to 50 metres," he said in an interview. His calculations concur with models developed by two international experts: David Petley, a professor of hazard and risk at Durham University in the United Kingdom, and Alessandro Palmeri of the World Bank. The government is in the process of installing warning sirens for residents of the Hunza and Nagar areas, which sit respectively on the west and east banks of the river.

It has identified nine relief centres where 60 days' worth of food, medicines and army doctors are to be positioned before May 25 - the earliest date by which the government believes the lake would brim the landslide dam. Attempts are also under way to develop back-valley pony tracks for jeep usage in the event that the Karakorum highway, which links Islamabad to China, is rendered unusable by the flash flood, and communities are cut off.

Irrespective of whether the dam crumbles or collapses, there is consensus that the outflow of the lake will change the low-lying geography of the Hunza Valley. Already, the outflow has gradually submerged three villages and the small town of Gulmit. Community leaders in four villages along the valley, from Ata-abad to Juttal near the southern convergence with the Gilgit Valley, recall a 1962 collapse of the Shamshal Glacier, one of the six feeding the present-day lake.

Khawaja Khan, a government doctor and voluntary head of a relief camp for more than 1,000 landslide refugees at Altit village, said the resultant flash flood had washed away half of what was then the thriving town of Ganesh, demolishing its Nagar-side portion and leaving behind the small village that is now located in Hunza. Syed Karim Ali Shah, a retired police officer in Juttal, a village of about 400 extended-family households on the Nagar bank, said he was a primary school student when the flash flood from Shamshal hit, changing the course of the river and destroying the previous settlement based on the Hunza side.

"That was caused by a blockage to one glacial stream. Six glaciers have fed this lake. The devastation will be utter and our lives will be changed forever," he said. thussain@thenational.ae