Every year across South Asia, as the summer’s exhaustive heat becomes unbearable, people wait for the monsoon to arrive. Monsoon first arrives in the Indian state of Kerala, around June 1st, then travels north during June and July. For weeks prior to the arrival of rain clouds, the media eagerly reports on expected monsoon arrival dates and analysts predict the ferociousness of the rainfall — will it be average, below average or perhaps above? Monsoon has a major impact on the economy and life of South Asia: the harvest depends on a good monsoon (though too much rain, of course, spoils the harvest as much as too little); nature comes alive and the landscape turns from dry and dusty to green and lush; water reservoirs are refilled; and temperatures drop substantially. All this means that when it finally arrives, the monsoon is greeted with celebrations.
Monsoon in the City
The monsoon, however, is a mixed blessing for cities. It can wreak havoc, bringing flooding and disease. Flooding and heavy rain disrupts traffic and public transportation services, forcing cities to come to a standstill, while also damaging buildings, destroying possessions and overloading sewer systems and stormwater drains. This, in turn, causes water to be contaminated, thus reducing the supply of clean drinking water. The accompanying storms cause trees to fall and debris to fly around, often killing bystanders. Meanwhile, other accompanying killers brought out by the monsoon rains and flooding include mosquitoes, carrying dengue fever and malaria, that breed in stagnant water.
As with most other problems in South Asia’s cities, the worst affected are the poor. They are hit disproportionally by the disruption to public transportation, diseases that flourish in slums and other cramped settlements, and the cold and wet weather that weakens the body’s immune system. Since slums and informal settlements are generally the least well planned from an urban planning perspective, they are also the worst hit by the flooding of roads and sewage systems.
Mumbai receives about 90 inches of rainfall during monsoon, and 50% of that tends to come in two or three heavy downpours, often lasting for days. According to Professor Kapil Gupta at IIT-Bombay, when this happens at the time of high tide, there is nowhere for the water to go and the city gets severely flooded. In 2005, Mumbai experienced its most severe flooding in recent times, with a complete shutdown of public transportation and communication systems. The consequences were the deaths of several hundred people, and about 100,000 properties damaged. In Bangladesh, Dhaka has been severely hit by monsoon several times, but this year, the port city of Chittagong has been particularly badly affected. Pakistan has also seen devastating floods, as is the case in 2010 and 2011, which has affected its cities.
Urbanization and Climate Change
The problem of flooding appears to be increasing, rather than reducing, in the urban centers of South Asia. This can be explained by increased urbanization together with climate change. As urbanization increases, so does the percentage of built environment within the city, simultaneously reducing the amount of land that acts as a natural drainage system. Roads and buildings stop the water from infiltrating the surface and, instead, increase the surface run-off. Poor city planning does not help this: often, developers are able to construct high-rise buildings on small plots of land without any regard for proper sewage or water drainage systems. A paper on flood management in the Asia Pacific highlights that in natural habitations without built-up environment, 25% of rainwater should infiltrate deeply into the ground, 25% should infiltrate at a shallow level, 40% should evaporate and only about 10% should run off. However, in the highly built-up cities of South Asia, the lack of natural surface means that only 5% of rainwater infiltrates deeply and 10% infiltrates into the shallow ground. Thirty percent evaporates, leaving a substantial 55% of rainwater to run off the surface into canals and drainage systems.
The effects of climate change further exacerbate the substantial increase in the amount of water that is not naturally absorbed by ecology. In recent years, heavy monsoon rains across South Asia may have reduced in rural areas, but has actually increased over urban areas, leaving already blocked water management systems to deal with additional increases in water. According to Dr. Dev Niyogi, Associate Professor at Purdue University, there are two theories behind this increase in city rainfall: the first theory is that megacities produce heat which result in storms when reaching the atmosphere. The second theory argues that the high level of pollution in megacities affect clouds so that rain levels increase.
In cities, the stormwater drainage system is made up of storm drainpipes, manholes, small channels, roadside ditches and culverts that are supposed to lead the water to larger channels, such as rivers or the sea. However, at the ground level, there is heavy encroachment of existing stormwater drain networks and canals as many informal settlements, such as slums, are built around these networks. The shelters and houses clog the drainage system since most of the ditches and canals are used for waste disposal, thereby becoming blocked by plastic bags full of garbage. The result is even more surface water, as well as increased filth in the flooded areas, due to the clogged canals and ditches.
In Dhaka, a city built on the world’s largest delta, the wetlands are reducing rapidly as urban sprawl reaches further and further out. New research by the Bangladesh Centre for Advanced Studies highlights that 52% of lowlands and 33% of water bodies, such as rivers and lakes, have disappeared due to urbanization. The result is a city that is increasingly prone to flooding as even relatively low levels of rainfall cause flooding and waterlogging.
Lack of Government Preparation
In spite of elaborate plans for ‘monsoon preparedness’ by local governments and city councils across South Asia, there is clearly a severe lack of adequate preparation for the water onslaught that is the monsoon. Many of the drainage systems are old, often from colonial times, but they are rarely maintained, repaired or renovated. One problem is the encroachment mentioned above which makes it difficult to shift settlements in order to improve the drainage system. In India, the government-funded Jawaharlal Nehru National Urban Renewal Mission is supposed to support such drainage system improvements. However, INR150 crore (~US$27m) is lying unused because of the delays and problems in moving encroaching slum-dwellers and others away from the drainage systems.
Still, the local government also has itself to blame. There is a clear discrepancy between the work carried out to prepare a city for monsoon, as stated by city officials, and the actual work that has been undertaken. Local media reports almost daily about clogged drains that are officially recognized as “clear,” and of roadwork, including filling large potholes, that was never carried out or simply stopped midway.
Much of the problem lies in administrative inefficiencies. While corruption is a major problem in allocating funds efficiently and ensuring that work is carried out as expected, there is also a problem in collaboration and communication between different city departments. For example, when drains are declogged, often the waste that has been removed is not properly disposed of for several days because it is another department’s duty to remove it. If it does rain in the interim, the waste that was removed from the drains simply goes back in. There is no evidence of systemic or integrated approaches to stormwater management.
Integrated Water Management
In stark contrast to the situation in South Asia, in Singapore, which also faces heavy monsoon rains, the government has implemented an integrated water management program across the city-state through its national water agency, PUB. The agency manages a Complete Water Cycle that includes all water-related issues from clean drinking water to flooding during monsoon, and harvesting and reclaiming water. Here, managing excess water during monsoon is part of a larger integrated water management system. Stormwater drains are kept clean and well maintained, and the more water that flows in the drainage system, the more water PUB is able to harvest and reclaim. Singapore has one of the largest rainwater harvesting systems in the world, and harvested monsoon water accounts for a substantial amount of water consumption on the island. Used water in the city-state’s efficient sewage system is reclaimed, and after going through a high level of cleansing, is being reused by the public, again operating as part of a larger water management system. With a well-built and integrated drainage network across Singapore, the risk of flooding has reduced substantially. Waterways acting as drainage networks are not only there for excess surface rain, but are integrated into the urban environment and landscape. In addition, Singapore has been raising low-lying areas and putting up temporary floodgates where necessary. All this points to a more long-term, integrated and systemic view on water and flood management as being part of the larger water management system.
Closer to home, in the absence of a reliable water management system for monsoon floods, an Ahmedabad-based structural engineer, Himanshu Parikh, has been working on a simple solution to urban flooding for those that are most affected — the slum-dwellers. Parikh had noticed that slums always develop along natural drainage paths. He therefore developed a “net of public infrastructure” that sees paved roads around the slum sloped along the natural topography and incorporating stormwater drainage. While Parikh first received a grant from the Overseas Development Administration for a pilot in Indore in 1989, he has since been able to launch projects in Bhopal, Ahmedabad and Baroda by using a three-way financial partnership between the community, local government and private sector.
Looking to the Future
As the monsoon season has now reached most parts of India and news of urban flooding are frequent in the media, it is clear that looking to the future, the current situation must change. The dual trends of increased urbanization (including a serious lack of planning of infrastructure in the increasingly built-up environment) together with climate change are only likely to further worsen South Asian cities’ ability to cope with heavy rainfall. Governments should treat urban flooding not as an unexpected emergency, but as an expected part of the yearly weather cycle. That means not only prepare for monsoon properly by cleaning the drainage system, but also look to new solutions for disposal of excess water. Cities such as Mumbai and Bangalore are simultaneously suffering from water shortage, so it seems apparent that an investment to improve monsoon rainwater harvesting across cities would be worthwhile. In the meantime, inefficient local administrations are unlikely to improve the situation in the near future, meaning that civil society or private sector solutions such as that by Parikh may be a better alternative to hoping for an integrated water management system such as that in Singapore. In the meantime, the citizens will wade through water, trying to get to and from work.