On January 4, a landslide knocked down houses, blocked the river and threatened the entire Hunza valley. Photo: Zulfiqar Ali Khan/AFP
The new year in the Hunza valley began with a catastrophe. On January 4, a crack in the sloped terrain of Attaabad in the Upper Hunza valley widened and gravity took its toll: houses in the village collapsed. A major landslide caused a wave of dust and gravel; subsequently, material from the moraine blocked and dammed the Hunza valley. Four months later, the villagers in the northwest of Karakoram still live in a state of uncertainty.
Attaabad is one of the younger villages in Hunza, inhabited by people from the central oasis five generations ago. The exposed location made irrigated agriculture difficult, favoured orchards and allowed easy access to the high pastures.
The crack in the slope had been discovered some time ago in the aftermath of the Astor earthquake. Humanitarian organisations such as Focus Humanitarian Assistance had assessed the likely danger and advised the villagers to leave their unstable abodes high above the Hunza river. Despite the timely warning, around 20 people lost their lives, 50 houses were destroyed and 1,500 people were displaced and forced to live in camps or with relatives and friends in neighbouring villages. The Karakoram Highway – while undergoing repairs by Chinese engineers – was damaged along a 1.5-km stretch. A lake formed upstream into Gojal where it submerged roads and bridges, lands and residences of Ainabad and Shishket. Recently it reached Gulmit, the largest village and tehsil headquarter of Gojal, however, the upper lake level has not been affected yet.
When the landslide occurred, the Hunza river released only 2% of its summer melt waters; day after day the run-off rate increases. The National Disaster Management Authority (NDMA) was assigned the task of mitigating the disaster by constructing a spill-over channel that stops the water level from rising and perhaps could support a controlled drainage. Time slipped away while politicians of Gilgit-Baltistan, development activists from NGOs, village representatives and council members, self-proclaimed experts and army engineers from the Frontier Works Organisation debated the future of the dam and lake. Some suggested utilising the lake water for power generation and/or tourism purposes; others discussed the stability of the dam without sound geological and geo-morphological evidence. There was also a call to bomb the dam.
Photo: AFP
Meanwhile, culprits were sought and demonstrations were staged against bureaucrats and politicians accused of inaction. The supply of basic foodstuffs and the transportation of ailing residents was initially enabled by army helicopters. As the crisis grew, a ferry service consisting of small boats was introduced that allowed some commuting and transportation of goods. On both sides of the lake, trucks meant to transport goods to and from Sost Dry Port, the hub of China-Pakistan trade across the Khunjerab Pass, became stuck. International trade along this one and only regularly functioning trade corridor between Central and South Asia has stopped for the time being.
Elders of Hunza society say the January landslide is the biggest natural disaster they have ever experienced. Hunza is a highly vulnerable environment and its extreme mountain valley system is characterised by the most extensive glaciation outside the polar regions as well as some of the steepest slopes on earth. Natural and man-made disasters are not unknown in the Karakoram; survival under these harsh environmental conditions has brought fame to the Hunzukuts for being capable and enduring mountain folk. To put the January disaster into perspective, its only necessary, to look back at history.
From 1830 to the 1990s, the details of 124 damaging events from the Hunza valley were preserved via archival sources, oral traditions, travelogues, reports, interviews and observations. The single most important destructive force has been the movement of glaciers. Glaciers have a role in nearly half of all recorded events. Glacial movements cause direct destruction when glacier advances cover cultivated lands, irrigation systems and roads. Glacier surges might be triggered by a variety of events, including landslides and rockfalls in the ablation zone, resulting in a significant deviation in glacier-surface velocities. In fact glacier advances and natural dams that cause lake formations can cause other disastrous effects.
Glacier dams can break, releasing the water stored in the temporary reservoirs and causing huge floods. The next biggest threat comes from snow and ice avalanches, which are as consequential as the combined phenomena of mud flows and rockslides. And while weather-related action from wind and thunderstorms has been of minor importance here, the heavy rains of September 1992 and 2001 caused substantial destruction to local infrastructure and agricultural resources. All these events have affected habitats, farmland, roads and bridges to varying degrees.
The present cultural landscape of the Hunza valley is the result of coping with these disasters. Direct earthquake-triggered mass movements have not been registered although 42 earthquakes occurred in the Hindukush-Karakoram region between 1876 and 1911. This run of seismic activity damaged roads and buildings, mainly in Chitral and the Gilgit valley. Out of 102 earthquake events with epicentres in Northern Pakistan between 1912 and 1971, no direct destruction to habitations could be established for the Hunza valley. The Attaabad disaster falls into this category: an earthquake contributed to the destabilisation of the slope, the slope collapsed years later causing the blockage of the Hunza valley and the formation of the Gojal lake.
Within the period of recorded observation there have been only four events that led to the complete abandonment of settlement sites in the Hunza valley. The 1830 mudflow and glacier advances in the Chupursan valley were the most dramatic events as a whole tributary valley of the Hunza river had to be sacrificed; all villages were destroyed and covered under a thick layer of fluvial deposits. Only within the last century has systematic resettlement resumed and continued until today – more than 330 households have built hamlets there.
Less than three decades later, in 1858, the severe rockfall at Sarat and the damming of the Hunza river caused flooding of all villages from Sarat to Pasu. In addition to the loss of village lands due to the undercutting of terraces, the juvenile village of Sarat was abandoned and resettlement took place after 1931. Both areas had been newly developed filial settlements of settlers from Central Hunza and of migrants and refugees from Wakhan who had superseded Kirghiz nomads and converted seasonally utilised pasture areas into permanent habitations with mixed mountain agriculture.
The case of Sarat holds an important lesson for the present Attaabad crisis. Sarat’s ground zero is within two kilometres from Attaabad’s danger zone and acts as a historical reminder of the scope of a disaster to be expected. In 1858 a lake was formed in a similar manner as now. When the lake had reached a length of more than 20 kilometres the dam collapsed and the lake released a flood wave that followed the course of the Hunza river into Gilgit and the Indus. The contribution from the Hunza river to the Indus was of such force that close to Attock, where the Indus leaves the mountainous terrain into its floodplain, the water level rose in virtually no time.
To quote a contemporary report: “At 5 a.m. on August 10, 1858, the Indus at Atak (Attock) was very low; at 7 a.m. it had risen 10 feet; by half an hour after noon it had risen 50 feet, and it continued to rise until it stood 90 feet higher than in the morning.” The speed of the rising flood waters drowned a colonial army that was camping on the bank of the Indus. The event took place when British dominance in South Asia was at stake and their supremacy was challenged. Because of the political significance the records of the 1858 Indus flood are well known.
What is likely to happen one and a half centuries later? If the Attaabad dam collapses and the Gojal lake empties at a high speed, the effects will be significantly more dramatic. During the 20th century the Karakoram Highway changed the infrastructure and livelihoods of people on the Indus and Hunza valleys in a manner that caused the expansion of follow-up construction of link roads, extension of village lands and settlements closer to the river banks. Nowadays every tributary river to the big rivers is connected by a jeep or truck friendly suspension bridge or concrete viaduct.
Development agencies, the Public Works Department – sometimes labelled the public’s worst department – and international donors have contributed to bridge construction and road building. The Tarbela Dam on the Indus claims to be the world’s largest earth-filled dam and is both the major regulator for Punjab’s irrigation and Pakistan’s prime hydro-electric power generation station. Above Tarbela, Basha Dam is under construction. Feasibility was attested despite high probabilities of earthquakes and flood releases. Damage caused by the Attaabad flood wave would be a mega disaster in every sense of the term.
While the NDMA predicted the lake to overflow by May 29, no significant damage was reported whenNewsline went into print on June 2. Although the lake’s water levels are steadily on the rise, Assistant Commissioner Hunza Zameer Abbas commented that the breach was unlikely for another three days. The NDMA has worked hard to enable a controlled overflow: they completed the planned spillway within the soft top layer of the dam. The spillway seems to be working as it is discharging the water building up in the lake, but the outflow to inflow ratio of 1000:3000 cusecs paints an unpromising picture. In addition, one news report suggested that the water leakage level had reached 350 cusecs on June 1. Other emergency measures have also been taken in the form of standby helicopters and early warning sirens placed at vulnerable locations to facilitate evacuation. But the glacier melt is increasing day by day, and as the lake exceeds a length of 14 kms, more terraced fields and orchards are inundated along with surrounding villages. No potato crop will be harvested this year; thus the only cash crop of the valley fades. The scope of the upcoming disaster seems to be grossly underestimated and in the meantime, residents wait with bated breath for the looming catastrophe and what could be Hunza’s worst natural disaster to date.
No comments:
Post a Comment