Lesson from a superstorm
Hurricane Sandy struck United States on October 29. It started as a mere Caribbean wave ten days earlier but as it closed in towards American shores it converged with a cold-weather system transforming into a Superstorm – a monstrous hybrid that delivered massive rains, winds gusting to the velocities of 85 mile per hour and tons and tons of snow. Deadly storm and a high tide in ocean delivered surges of over 13 feet at Battery Park and the Statute of Liberty gazing from the southern tip of Manhattan.
By the end of the three-day mayhem, at least 8.5 million people were grappling in the dark across 13 States and the nation’s capitol. The storm claimed 68 lives in the Caribbean, 38 in United States, forced half-dozen US nuclear-power plants to slow or shut down and brought transportation system of the East Coast to a grinding halt – the rest is sad history.
Such ire of nature is not uncommon or alien to our people. During the last 40 years, Pakistan has been struck by more than a dozen furious storms followed by massive flooding, loss of thousands of lives and billions to the economy.
Disastrous weather events should not be seen in isolation or classified merely as nature’s fury. The sequence of such events in Pakistan matches World Meteorological Organisation’s Inter-governmental Panel on Climate Change (IPCC) projecting frequent and intense weather events during years to come.
But does that demand building new dams and additional infrastructure over increasingly troubled rivers? Hasn’t our plumbing approach towards nature already killed thousands, caused undue and excessive losses? After all why should Sandy kill only 38 in USA but we lose thousands every time a butterfly flaps its wings in some faraway lands?
How does it all work?
Could we just look at one set of events say for example, those that took place during 2010?
Monsoon should be viewed as a giant sea-breeze with ocean moisture sucked in by rising hot air over the South Asian plains. Since April there were warnings of abnormal monsoon rains for Pakistan due to a well established El Nina in the western pacific that had risen normal surface temperatures of the Indian Ocean by almost a degree.
Monsoons are also influenced by large scale weather patterns such as the swiftly flowing, westerly air currents called jet-stream located high above the earth’s surface. They affect the Asian Monsoons over the Tibetan plateau where the warm equatorial air, after rising and flowing pole-ward, descends on the subtropical areas to flow back equator-ward. This jet-stream wobbles north and south as it flows around the Northern Hemisphere. As it shifts, the jet-stream drags the weather systems along.
During July, meteorologists noticed the jet-stream coming to a halt as a consequence of Rossby Waves created by the earth’s rotation. Normally, these meandering waves are overpowered by the jet-stream’s force, but that year‘s much weaker stream resulted in unusually hot summers leading to the breakout of wildfires in Russia, and unprecedented rains that poured over the slopes of the Western Himalayas. Gushing quickly down the tributaries into the Indus River the rain waters gave rise to floods of catastrophic proportions.
But being one of the largest rivers of the world Mighty Indus should have been able to carry out the excess waters into the Arabian Sea.
So then, why did it fail in its job as a drainage channel?
Over the last hundred years or so, with funding from International Financial Institutions, a series of dams and barrages have been built along the hill slopes to prevent water from reaching the Indian Ocean. Instead the irrigation system diverts Indus waters through a large but flimsy canal system into great swathes of land. Such human intervention ultimately defeats even a river like Indus to mitigate the effect of even ordinary floods.
In this season of judicial activism, Chief Justice Umar Ata Bandial of Lahore High Court while hearing petitions which claimed that the failure to construct the Kalabagh Dam would make the agricultural land barren; admonished the federal government for failure on its part to develop consensus over the project. He went on to observe that the objections raised by Sindh and Khyber Pakhtunkhwa over the construction of the KBD were political and that aggravated the national flooding situation due to global warming necessitated construction of additional water reservoirs.
Political ramifications aside, it is universally acknowledged that dams are disruptive, they never meet their project targets yet isolate populations of species human or otherwise living up and downstream, cuts off fish migrations forcing inbreeding from smaller genetic pools and together they emit 104 million metric tons of methane annually or 4 per cent of the total global warming impact of human activities due to the rotting of the vegetation.
To understand KBD’s potential of long term impact over Indus one needs to appreciate geophysical and geological environment of the proposed dam-site that lay in the precincts of Salt Range. The actual layer of salt rock may be two kilometers below the surface but there are salt deposits and alkali brines at low to medium depths. Have the geniuses pushing for the damned dam considered the intense probability of salt solutions rising and mixing with water of the reservoir under tremendous pressure of 260’ of vertical water storage?
WAPDA anticipate filling its dams by end-August every year. However the torrential rains of 1992 that caused the worst recorded flooding over Jehlum River started late on September 19. The inflows at Mangla Dam reservoir that stood already full jumped from 28,000 to a million cusecs in less than 24 hours! According to inquiries later the Chief Engineer facing charges of criminal negligence had no option but to open the floodgates that resulted in inundation of more than 15,000 villages. According to a recent report 20 smaller dams constructed during last 10 years by the Punjab Small Dams Organisation to provide water to 30,000 acres of farmland due to faulty design, were only irrigating 2,044 acres, or only 7.45 per cent of the target area.
Imagine Kalabagh Dam 130 miles downstream Tarbella which shall raise water levels from 655’ to 915’ MSL, rains like 1992 or 2010 towards end of monsoons in Tarbella/Kalabagh catchment area and Chief Engineers being forced to open floodgates to save their damns! Someone with rudimentary knowledge of mathematics could calculate the force generated by billions of gallons of water gushing down 275’ gradient over that short run but, even a layman like me could tell you it would be nothing like the Tori breach! Must leave it to your imagination the scale of catastrophe forty-miles downstream hitting Chashma Barrage, nuclear power plants, Ramsar site and the settlements could bring.
The author is a social activist, a member of Citizens for Democracy and the former Administrator of Karachi.