In Pakistan, floods are the single most damaging natural hazard, with 21 major floods having ravaged the country between 1950 and 2010. According to an Asian Development Bank report, around 8,887 fatalities were reported in this period. In recent years urban floods have become a common occurrence in many cities across Pakistan.
The 2010 mega flood impacted the lives of nearly 20 million people. This mega flood alone is estimated to have caused losses worth $10 billion in lost productivity due to damages to infrastructure, agriculture and ecosystem services. During the following five years, a major flood event occurred at least once each year, affecting millions more. In the recent past, urban floods have become more pervasive all around the world. The same has happened in Pakistan. Major urban centers, particularly Karachi and Lahore have become increasingly prone to urban floods. To prevent cities from this, Pakistan needs to spend a lot to upgrade the existing infrastructure. Increasing risk, combined with changing climatic conditions, points to an urgent need for the prioritization of urban flood risk management on the political and policy agenda.
There are many reasons that cause urban floods in Pakistan’s major city centers. Some of the key causes are: (1) hydro-logical and meteorological extremes, (2) unplanned settlements, (3) climate change, (4) old sewerage systems, (5) overpopulation, (6) population influx in cities due to lack of opportunities in suburbs.
Urban floods are an outcome of a number of hydro-logical and meteorological extremes. This includes excessive flows and precipitation in a short period of time. However, these are not the only determinants of urban floods.
Unregulated development in urban centers is one of the major reasons for urban floods. This is so because flood protection infrastructure is usually missed in the areas which are developed without planning. The situation becomes worse when an already poor sewerage system comes under stress due to heavy rainfall.
Urban floods have consistently hit Karachi and Lahore in recent years. Even when the Meteorological Department warns of urban floods, no great measures can be taken as sewerage/ drainage systems in these cities have low capacity to perform even during normal days. This is the very reason that mid-August torrential rains in Karachi resulted in over two dozen people losing their lives. The mayhem caused by the rain spell exposed serious shortcomings in planning, development and management of the city.
Unplanned localities in big cities are mostly built around waterways and natural drainage channels. In Karachi, according to Sindh Katchi Abadi Authority, there are 5,639 slums. Most of them are alongside drains. Urban floods affects them in the worst possible way along with the higher risk of human loss. Due to such a huge number of slums, drains get encroached and it blocks the natural drainage channels. Some of the drains in the city have also become the sites for solid waste dumping.
This means that rainwater in the city has nowhere to go. This year, the death toll mounted to over thirty-five in Karachi alone. Among them, at least eleven died of electrocution. Due to the over spilling of drains and the absence of properly directed flow of rainwater, streets, transit ways and lanes were rendered unusable. The city was virtually paralyzed with people restricted to their homes. The deluge caused an electricity breakdown in most of the city and the Karachi Water and Sewerage Board’s pumping stations, as a result of which the city could not be provided up to 250 million gallons of water.
Developing sponge cities or sponge colonies can be a possible solution. A Sponge City is a city that has the capacity to mainstream urban water management into urban planning policies and designs. It should have the appropriate planning and legal frameworks and tools in place to implement, maintain and adapt the infrastructure systems to collect, store and treat (excess) rainwater. In addition, a “sponge city” will not only be able to deal with “too much water”, but also reuse rainwater to help to mitigate the impacts of “too little” and “too dirty” water.
The week long 2016 floods in China killed more than 180 people and affected 32 million people across 26 provinces with losses crossing 50 billion Yuan ($7 billion). Wuhan, the most populous city in central China, was hit hardest. Home to 10 million residents, Wuhan’s transportation network was paralyzed, 14 city residents were killed and more than 80,000 residents were relocated. A year before the flood Wuhan had been declared one of the country’s first 16 “sponge cities” – areas piloting ecologically friendly alternatives to traditional flood defenses and drainage systems. The pace of the project was accelerated in the aftermath of the floods. Under the sponge city scheme, Wuhan and the other participating areas must ensure that 20% of their urban land includes sponge features by 2020, with a target of being able to retain 70% of storm water.
Pakistan can also consider the same model to mitigate the threat of urban floods. Other international case studies that provide possible solutions to urban floods should also be looked at. There are many examples, one is that of the ‘Wait…’ campaign in New York City. The campaign asks New Yorkers to delay doing laundry, washing dishes, or taking long showers until after a heavy rainfall event. This reduces pressure on the drainage system and helps flush out rainwater from urban areas. The city is also implementing more affordable green infrastructure initiatives, such as developing natural catchment areas like rain gardens, park spaces, street trees, and permeable pavements. All of these solutions seek to reduce the amount of storm water that enters drains in the first place. Hamburg has introduced a separate rain water drainage system in recent years and introduced financial penalties, if rain water is not locally drained by home owners.
As a first step in urban flood risk management, policy makers need to understand the flood hazard and its impacts through a better understanding of the types and causes of flooding, probabilities of occurrence, weather and climatic patterns and their extent, duration and intensity. Knowing where and how often flood events are likely to occur and what population and assets occupy the potentially affected areas is equally important. There is also a need to decrease the rapid rate of urbanization.
According to a 2015 report, a million people from other cities and rural areas migrate to Karachi every three years due to its high employment opportunities. According to World Wildlife Federation (WWF-Pakistan), an increasing proportion of these migrants include those who have been displaced due to an increase in catastrophic floods caused by melting glaciers or those that have been impacted by the rising droughts in the warmer regions. The 2017 population census has shown that Pakistan has moved up the ladder, becoming the fifth most populous nation only behind India, China, the US and Indonesia. With a staggering growth rate of 2.4pc per annum, the country’s population is around 207m.
Pakistan is also consistently among the list of countries most vulnerable to the threat of climate change. This means that we are putting more and more people in harms’ way. Even more worrisome is that this population explosion and its serious implications have been hardly figured in the national discourse. 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 urbanization and smart cities together with infrastructure to facilitate urban development.
The Disaster Management Departments of each province should work in a strategic way in terms of their preparedness, forecasting, response, and rehabilitation. Just relying on forecasting can never make the situation better since climate change has made the early forecasting uncertain. Preparedness and effective emergency response can help stem the losses. Pakistan, being the signatory of Sustainable Development Goals (SDGs) also has a responsibility to perform in this direction. SDG 11 targets the reduction of losses in cities from water and other disasters to protect vulnerable communities. The rising incidence of urban floods — caused by torrential rains, flash floods, and storm rush or overflowing rivers — has obstructed sustainable development. We would do well to begin now, before the problem of urban floods worsens as it has done in recent years