By: GM Shimshali
Viržrav Lake in Shimshal valley of upper Hunza is a notorious artificial lake, known not only for its periodic outbursts leaving devastating socio-economic impact, but also for the immense psychological impact it has on the communities in Shimshal, and those living downstream, from Gilgit-Baltistan, to Punjab and Sindh. This fear of the Shimshal Lake outburst has lingered for decades, and perhaps centuries. The psychological impact of the past devastation can clearly be seen in the eyes of elderly villagers who saw the 1960s great outburst.
Most of us may not know about how it traumatized people for decades, because it was, by and large, silent for the last 57 years. Come 2017, and the giant seems to have awoken, yet again.
Historically Viržrav Lake ensues due to surge of Khurdopin glacier, a 47 meters long glacier junctions with Yukshin Gardan glacier in Khurdopin Valley, where it bumps into the side rock wall of the valley and blocks Vīrjerāb River that results in formation of a gigantic temporary artificial lake. The lake expends for several months and outbursts when the glacier surge retreats. Millions cubic feet stored water flows in Hunza River in a short span of time and destroys everything on its way. According to local people, the lake outburst befallen three times(1920,1942 and 1960-64) in the 19th century that washed away half of Shimshal and Passu villages with full intensity and also damaged agriculture land, settlements, bridges and roads on its way down stream.
The indigenous knowledge of local people also reveals that the glacier surge cycle is on average 20 years and the movement lasts up to three years during each cycle, but sometimes the water drain shortly as the glacier surge remains slow and downturns quickly. In such a scenario, medium intensity of flood can be expected, which was experienced in 1999 and in 2017 that damaged roads, agriculture land and posed immense difficulties for the inhabitants in the valley. Currently the speed and intensity of the glacier movement is abnormal which resembles with that of the situation in 1942 and the Vīrjerāb River is turned into a frozen lake, so the alarming situation in the near future is likely to happen.
Scientist (including NASA) are studying the glacier movement using high-resolution optical satellite images, who have confirmed that the glacier is moving with fast pace which may grow further and result in a sudden flare-up. But they are yet not confirm about the volume of flooding and destruction downstream. A study by Jakob F. Steiner (Utrecht University’s Physical Geography Department) shows that for a few weeks in 2017, Khurdopin glacier’s velocity peaked to above 5,000 metres per year (ma-1), which is among the fastest rates reported globally(see the link below)
Some Disaster Risk Reduction related institutions (AKAH and GBDMA) in Gilgit-Baltistan with support of local community are regularly monitoring the glacier activity and they have also confirmed that the situation is getting worsened, however, it is still chaotic for them to give a clear point of view about high intensity outburst. They are considering all three possible scenarios of small, medium and large scale floods intact and expecting to get a clear picture by March, 2018.
Video link: https://www.youtube.com/watch?v=IFQa9jxIgA4
Considering the historical fact of the disasters over the past century, it can be effortlessly foreseen that in worst case scenario villages along its way are many ways at high risk. The outburst of lake can wash away roads, bridges, settlements, agriculture land and other livelihood sources and leave thousands of people homeless downstream along Indus River.
The fact cannot be ignored that the situation may get even more calamitous if the burst of the lake is like that of 1960, its disaster magnitude may become be doubled due to Ataabad Lake on its way.
Knowing the fact that there is quite possibility of overwhelming disaster, Local Community Based Institution, GBDMA, NGOS and other concerned institutions in Gilgit-Baltistan have become mobilized toward preparatory measures. But the situation may go beyond capacities and resources of provincial level setup and national level intervention is deemed necessary. It is evident that if the situation turns exacerbated the destruction will not be limited to Gilgit-Baltistan but will also be experienced in Punjab and Sindh along Indus River. The issue must be given due importance at national level proactively.
The necessary actions would be certainly required before it gets too late. The required actions can be:
1)Forming a team of national and international experts visit the glacier to assess the situation in order to sort out possible ways of water drainage.
2) Establishing an early warning system in case of Lake Outburst found probable,
3) Prepare action plan for evacuation in emergency situation, and
4) planning for relief work must be done in advance as access to the upper villages may cutoff due to possible damage of roads and bridges.