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Urban flooding threat

April 17, 2018

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THOSE fortunate enough to have access to a proper drainage pumping system and sanitation in their neighbourhood might be safe during the monsoons — but millions of others across the country should get ready to deal with urban flooding. By 2050, Pakistan’s population would have swelled from 207 million today to 242m. Almost half the people will be living in the urban areas. There is an immediate need for an improved urban infrastructure.

SDG 11 targets the reduction of losses in cities from water and other disasters to protect vulnerable communities. The rising incidence of urban flooding — caused by torrential rains, flash floods, storm rush or overflowing rivers — has obstructed sustainable development.

Karachi, Hyderabad, Islamabad, Rawal­pindi, Peshawar, Lahore and Faisalabad have all faced urban flooding and its attendant devastation during the monsoon season. Measures to cope with flood risks are administered by provincial and other authorities, such as the Met department, disaster management bodies, the irrigation department and the military. But they may not always be successful. The provincial disaster management authorities continue to warn of heavy rain patterns that cause urban flooding.

True, some efforts have been successful in reducing urban flooding and can be emulated. For example, the Leh Nullah in Rawalpindi is subjected to drainage flows from Rawalpindi and Islamabad and from rainwater from the southern part of the Margalla Hills — three pressure points. A project was initiated by the government in 2016-17 to clean up the Leh Nullah and the storm-water drains at vulnerable points. A clear improvement was witnessed after the effort.

Are our cities prepared for the approaching monsoon season?

Another solution for improving the urban system focuses on developing smart cities. The idea, discussed in Vision 2025, is to improve the resilience of cities. The Vision 2025 document discusses urbanisation and smart cities together with infrastructure to facilitate urban development. This is fine but the question remains: when and how will urban governance be implemented? It is worth searching for possible solutions to urban flooding in international case studies.

One example is of the ‘Wait…’ campaign in New York City, which provides unique solutions to deal with urban floods. The campaign asks urban residents, particularly of the Brooklyn area, to avoid the use, as much as possible, of water during rainstorms. This reduces pressure on the drainage system and helps flush out rainwater from urban areas. This campaign uses volunteers to send text messages to residents before the rain starts to avoid the use of water during rainfall. It is found to have made quite a difference.

To their credit, commercial enterprises have also highlighted ways of reducing urban flooding, often by giving examples. One solution is found in China, where urban flooding has increased over the years. It involves the creation of ‘sponge’ cities; Wuhan is one example. ‘Sponge’ cities ‘hold, clean and drain water in a natural way’, instead of just channelling away the rainwater. It can help in the reuse of water for gardens and urban farms, recharging depleted aquifers, and cleaning and processing flushed water for other purposes. Similarly, rooftops gardens in Europe store rainwater and reduce pressure on the drainage system during the rains.

Yet another solution focuses on separating the drainage system from rainwater — something that many cities are looking into. Installing separate infrastructure can reduce the pressure on the drainage system during the rainy season.

Perhaps one of the most obvious ways to minimise the damage caused by the monsoons in the cities is simply to keep the drainage system unclogged, as discussed in the Leh Nullah example; regular cleaning of storm-water drains is needed, ensuring that pipelines are not choked with sediment, debris, waste, etc. Unfortunately, poor municipal services and non-functioning local governments hinder this most sensible of measures. In large cities, such as Karachi, clogged storm-water drains have caused streets to be flooded with dirty water and disease-causing waste.

When such basic measures are not taken, it is perhaps difficult to imagine the government rising to the challenge and studying international measures that have turned vulnerable cities into clean, green, livable spaces. Nevertheless, these examples can provide a blueprint for ways to minimise losses from urban flooding — especially in conjunction with local solutions.

There are several innovative solutions being applied in different part of the world. Along with examining these and seeing how appropriate they are to local conditions, suggestions for viable options must also be taken from students of city and town planning, urban development, architecture, etc, apart from engaging the development authorities. We would do well to begin now, before the problem of urban flooding exacerbates as it has done over the decades.

The writer is research assistant at the Sustainable Development Policy Institute.

Published in Dawn, April 17th, 2018