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‘Rain, rain, go away…’

September 18, 2011

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“IF you want the rainbow, you gotta put up with the rain,” sang Dolly Parton. But that was before the days of escalating climate change.

Today, the opening up of the skies only leads to chaos and gloom the world over, especially in rapidly growing, massively crowded cities in developing countries.

Rain has been falling on what is now 3,500-plus square kilometres of Karachi ever since this planet emerged about 4.5 billion years ago. As part of this hydrologic cycle, the sun heats and evaporates water in oceans, plants and soil. The rising vapour cools and condenses into clouds. Rain and snow precipitates, falling back onto land and sea.

On land, the rainwater flows as surface runoff, eventually snaking into nallahs and rivers. Some runoff soaks into the ground and replenishes aquifers. Over time, the water returns to the ocean, where the water cycle restarts.

This repetitive action over billions of years has established paths and routes for rainfall, cutting ravines, gullies, channels and rivers which quickly drain water from the land surface.

Until 200 years ago, rainwater flooding was not a problem in Karachi. In 1800, the fishing village in Talpur jurisdiction had less than 8,000 inhabitants, increasing to around 17,000 in 1850 under the British, and then to 116,000 at the century’s turn.

The emergence of Pakistan in 1947 saw Karachi with some 400,000 residents, exploding to 1.1 million by 1951 and to some 16 million today. During this period, administrators and citizens have progressively destroyed the natural storm-drain system (evolved over 4.5 billion years), creating all sorts of barriers to the established flow.

What do sane societies do? When a habitation emerges, the elders or planners are aware that the natural slope of the land must not be disturbed. Rainwater that falls on buildings is led to ground level, and then moves along the slope of the land to the road which acts as a minor collector of storm-water.

Construction is carefully controlled by establishing a convex curve (camber) across the road width (with a central high point) and shallow drains along the two sides near the pedestrian sidewalk, sloped along the length of the road in the general direction of the nearest storm-drain. The primary function of roads being traffic movement, the drainage function is subservient and cannot interfere with traffic function.

Minor roads drain into larger roads, which act as intermediate or major collectors, before emptying into storm-drains established in natural channels that have been carved out over millennia. A network of nallahs joins rivers and finally meets the sea.

To repeat, in sane societies, the use, levels and slopes of plots, roads, storm-drains and components of the layout of a city are carefully controlled by the municipality. Large swaths of land are left unpaved so that rainfall can seep into the ground. No one is allowed to raise the level of any land, erect any impediment to water flow, construct roads without camber and side drains, or obstruct a ravine or gully.

The requirements of the storm-drain master plan are strictly enforced by the building control authority, the urban-planning bureau, the road construction department, the anti-encroachment cell and other related municipal agencies. So when it rains, the water flows away and there is no flooding.

We do exactly the opposite in Pakistan’s urban conglomerations. We fill and raise plot levels at will, make buildings with high plinths, erect walls, disregard natural land slopes, construct/repair roads by piling additional material on top of old surfaces (instead of removing the excess), have no camber or side drains in streets, encroach with katchi abadis on nallahs, constrict marine outfalls, and other similar lunacies.

We utilise our storm-drain channels for sewerage, thereby robbing them of the capacity to cope with rainfall. Forgetting that ‘safai nisf iman hey’ (cleanliness is half of faith), we clog the drains with garbage and rubbish. We do not devise storm-drain master plans, and even if we did, do not have the will to enforce them.

As a result of this gross stupidity, two inches of rain paralyses Karachi (or Hyderabad, or Lahore or Faisalabad), with residents dying in collapsing dangerous structures and many more electrocuted by fallen wires.

Low-lying areas are inundated, adding to the miseries of the poor. Traffic on arteries is clogged (affording armed muggers hapless sheep for the slaughter), and scarce electricity supply disappears for days on end; in short, mayhem reigns. To call this a ‘natural disaster is a blatant untruth: it is a ‘man-made disaster’ orchestrated by the government and municipal authorities.

The spine of Karachi, Sharea Faisal, over the past 60 years has been raised four feet above the level of the 150-year old Christian graveyard, turning it into a quagmire. The military offices of the same era on this major artery lie some three feet below road level, all subject to flooding.

Last Tuesday, in Karachi, the chief justice of Pakistan clambered from one vehicle to another amidst floodwaters outside the Supreme Court building to get to the suo motu hearing on Karachi’s violence: in his chambers he dressed down the city district coordination officer who promptly suspended the senior-most officials of the municipal services department for not cleaning up the storm-drain. Problem solved?

The recent colossal rain damage in the rural areas of Sindh, caused by defectively planned drainage systems and canal breaches merits separate, rough, treatment.

With global warming, the rainfall situation is worsening and cannot be wished away. Can we not develop — and implement — sensible storm-drain master plans in our cities? Does the stupendous cost of damage to lives, property and business not make this imperative?

arfc@cyber.net.pk