Work on War footing required to release the water from Hunza Lake- Nazir Sabir

GB TIMES REPORT

Islamabad: Nazir Sabir talking to GB TIMES stated that the well known mountaineer and politician from Hunza, stressed that the work on the debris that has blocked Hunza River should be speeded up on the war footing.  He stated that FWO is involved in the process of releasing water from the lake which could be appreciated, however the pace of work is very slow, and delay which is putting the whole region of Hunza-Nagar, and Gilgit throughout the Indus River at high risk.

He further stressed on developing an early warning system for the information of people in case of the danger of out-burst of the water.  He was of the opinion that in Hunza-Nagar District and Gilgit food items must be stored in huge quantities  as the bridges on KKH and KKH itself will be destroyed with the flooding of lake water.

One Response to Work on War footing required to release the water from Hunza Lake- Nazir Sabir

  1. Dr. Bushra says:

    Hunza Lake- destroy it before to save Tarabala Dam
    Arshad H Abbasi
    ahabasi@gmail.com
    It was in the 3rd week of July 2004, while traveling toward Khunjerab, that we stayed for a few hours at Atabad . The locals drew our attention towards a ‘crack’ in the slope above their village. The crack approx 1 1/2feet wide also passed through some of the hamlets. It was generally felt, that the November 2002 earthquake caused this crack, while some felt that the heavy snow accumulation of glaciers could have put pressure on the slope. Authorities were informed by the locals of the crack, which kept on widening, but no one took notice of it. I personally felt, that if no remedial measures are taken, this huge chunk of mountain side would one day slide into the river. No interest was shown at any level, and ignored was the willingness of the local people to be shifted to the Punjab.
    It was most disturbing therefore, when on 4th January 2010 the news came, that the mountainside had actually collapsed. 13 people dead and a steadily rising artificial lake, upstream of the blockage, continues to inundate vast stretches of agricultural lands, orchards and home, the only source of livelihood for thousands of people. The increasing water pressure has the potentials of breaching the massive debris, which has dammed the natural flow of the Hunza River for 2 km, if rapid preventive measures are not undertaken. The effect a sudden breach would have downstream is unimaginable, as the Tarbela Dam is the backbone of Pakistan’s economy, its agriculture and hydropower. Due to the loose nature of the debris which at its lowest point is 100m above the riverbed and the absence of controlled spillway, this landslide dams may fail without any warning and can carry massive sediment (debris) with it. A common failure scenario may occur with a variety of failure processes that includes overtopping, seepage and sudden sliding caused by piping but there is greatly that it would surely burst.
    As the debris blocking the Hunza River is mainly fine-grained material, boulders and pebbles which do not have the capacity to support this dam much longer, especially since piping has already started. It is not unknown, that a force of water can destabilize massive deposits and cause extreme devastation downstream.
    The Indus River is one of the world’s largest rivers in term of water sediment loads and this massive debris (sedimentation) would have serious impact on theTarbala Dam, as it could completely dislodging the vast delta which dramatically expanded over the past decades at the mouth of the Indus. Should the dam created by the debris breach, it is said, that flash floods with a height of between 60 to 80 feet would create disaster along the embankments of the Indus River.
    In other countries, risk analysis study would immediately have been undertaken by a team comprising Remote Sensing, GIS, Hydrology and Risk Management experts to quantify the potential risk in case of a breach in the artificial lake/dam. There is a urgent need to develop a high-resolution digital terrain model (DTM) to determine longitudinal profiles and cross-sections of the river at 500 meters interval up to Junction of Hunza and Gilgit River and than through to Besham Qila. Simultaneously a team of Metrological Department and WAPDA, needs to conduct a quick but comprehensive study using remote sensing images, digital elevation and housing data, hydrological and spatial analyses to quantify the potential risk in terms of affected population size and estimated property losses.
    Emphasis needs to be placed on the characteristics of the breach, i.e. the geometry of a possible breach and how long it would take to develop needs to be formulated. Different types of dams tend to collapse in different ways and hence breach characteristics have to be defined first. If this dam/lake isl not thoroughly assess and properly disposed of, it would be catastrophe for downstream areas including a great threat to Trabala Dam.
    The loose nature of Attabad-Hunza landslide and with the absence of controlled spillway, this landslide dam may fail without any warning and can lead to downstream flooding with massive sediment (debris) flow. A common failure scenario could occur by overtopping, seepage and sudden sliding through excessive piping. Priority needs therefore be given to engineered breaching with precise technique to control sediment flow consider, before we have another “Zalzal Lake”. The “Zalzal Lake” was formed due to earthquake-2005 in Azad Kashmir and on February 09, 2010 its sudden failure caused water flooding onto the lower areas.
    The best model for our experts is the case of the Tangjiashan Lake. It was created during 2008 Sichuan earthquake in a extremely rugged terrain of Tangjiashan Mountain in China. The water was level rising at the rate of 8 feet day. When the capacity of lake was reached more than 200000 acre-feet Chinese engineers, scientists, and army considered three options. One was to use engineering techniques, including blasting, to release the water. The second was to reinforce the dam during the flood season. The third was to restructure the quake lake into a reservoir. All three schemes had evaluated after the speedy risk analysis study, including development of a high-resolution digital terrain model (DTM). After assessing all threats more than 250,000 people had been evacuated from downstream area in anticipation of the Tangjiashan Lake dam bursting.
    In May 2008, before start of flood season it was finally decided to breach the dam. Chinese army took ten days to drain water from the lake. Chinese army engineers used recoil-less guns, bazookas and dynamite to blast boulders and other obstructions in the channel and final massive blasts broke through the “bottleneck” in the spillway, the water outflow speeded up drastically. So the Tangjiashan Lake was emptied thus succeeded to eliminate a huge threat of a disaster.
    The need of the hour is to predict and avert colossal losses in landslide prone areas of Pakistan, a comprehensive landslide hazard analysis and mapping ought to prepare at the earliest. Who will do it? For this Government has to transform Nation Disaster Management Authority into a proactive organization.

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