Tarbela Dam & Karkoram Highway Threatened in Pakistan

March 13, 2010
C N Anand

In 1840, upstream of the Indus, in the Shyok tributary, an ice bridge collapsed to form a dam resulting in the creation of a lake 19 Kms long, 800 meters wide, and 120 meters deep. When the dam breached, a 20 meter high wall of water and mud barreled down the gorges of the Indus, and burst into the plains at Tarbela, and reached Attock in two days time. The massive flash flood of mud devastated the Sikh army camping on the banks of the Indus near Attock! History would have taken a different course if the Sikh army had not been devastated!

In 1858, a similar landslide on the Hunza river (tributary of the Indus) created a reservoir. This also burst. Cultivated land was scoured out and villages flattened. When the flood waters reached the confluence of the Kabul river and the Indus, a reverse flow up the Kabul river, up to 50 kms, was created.

Coming to very recent times, two months ago, on 04 January, 2010, a portion of a mountain gave way to block the Hunza river at Atabad, in the Gilgit-Baltistan area. After hitting the lowest portion of the valley, the land-slide climbed up the opposite hill side and damaged the Karakoram Highway (KKH). Trade with China on the KKH remains disrupted since then. Fortunately, the water flow in the river is low in January, but the flow picks up as temperature rises and snow starts melting. By 27 February, 43 days after the landslide, the longest Bridge over the Hunza, 11 Kms upstream of the landslide area, got submerged. The water level is expected to rise another 30 meters above the bridge. The Karkoram Highway hugs the banks of the Indus and Hunza, crossing over at regular intervals to the opposite bank and back on bridges. Upstream of Atabad, the KKH is now submerged for a length of 15 Kms.

The final size of the lake is expected to be bigger than the lakes formed in 1840 and 1858.

The block in the valley at Atabad is long but narrow like the cork of a champagne bottle. It is 3000 meters long along the valley, and 200 meters wide. On top of the block, earth moving equipment has been placed to doze down the height to meet the rising waters at the earliest. The narrowness of the block restricts the number of dozers that can be deployed. Snow melt and water seepage has made the top of the earth block slushy and boggy, hindering the functioning of the earth moving equipment. The water flow is increasing day by day as temperature rises, resulting in the water level rising faster. In the race against time, the Pakistani engineers seem to be loosing. When the water level reaches the top of the landslide and starts spilling over, erosion will occur. Hopefully, the dam will be washed out slowly and not burst.

The difference between the earlier two situations of 1841 and 1858 and now is that Pakistan has created a lot of assets in the form of the Karkoram Highway (KKH) with many bridges, and the world's largest earth and rock-fill dam, the Tarbela dam. If the dam at Atabad bursts, the wall of mud will rip the KKH along the entire length of the Hunza and the Indus, till Tarbela. Bridges will be devastated. If the Tarbela reservoir is at the dead level as it is now, the wall of mud will push the sand delta over to overwhelm the off take tunnels, and clog up the turbines. The Tarbela dam will have to be written off, which will spell economic disaster to Pakistan.

Pakistan is advised to stop letting out water at the Tarbela dam immediately, and store water to a height of 30 meters above the dead level. The cushion of water in the reservoir will absorb the wall of mud well upstream of the dam and not allow the existing delta to be nudged forward and spill. The catch is that the Rabi crop will have to be allowed to wither away. Unfortunately, Pakistan is facing a drought.

The question that should be boggling every Indian's mind is how can India help? In the impending chaos, what will happen to the nukes? How will China be effected? Will history take another wrenching turn?

An Urdu translation, Tarbela Urao -- Pakistan ko Jhukao, of C N Anand's novel, Tarbela Damned Pakistan Tamed, is available in Pakistan.
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