Uncontrolled urban expansion and poor drainage put slums at risk from extreme weather, while water resources are under strain
COLOMBO (AlertNet) – Every time it rains hard in Sri Lanka’s capital Colombo, parts of the city are quickly submerged, creating massive traffic jams. Urban flash floods have become a regular occurrence here, with monsoon rains arriving in short, intense bursts.
Niranjith, who drives a three-wheel rickshaw in the suburb of Ragama, recalls how a year and half ago, filthy water suddenly began coursing through his parked vehicle less than five minutes into an abnormally torrential burst of rain. “All the dirt in the open sewers was running down the roads, because the clogged drains had begun to overflow,” he said.
The city authorities are aware that, in congested, densely populated urban areas, rainwater flows into the roads because many drains are blocked and areas that naturally retain water have been built on.
“As the housing stock expanded, low-lying areas and marshland were filled for construction purposes,” Gotabaya Rajapaksa, Secretary to Sri Lanka’s Ministry of Defence and Urban Development, told a World Bank workshop on sustainable urban regeneration in Colombo in late March.
“This seriously reduced the catchment areas available for water retention, and construction-related activities have also often obstructed the canals and waterways that are critical for drainage. As a result, monsoon rains can cause significant flooding in Colombo,” he explained.
This growing problem is not restricted to Sri Lanka, according to Abha Joshi-Ghani, manager of the World Bank’s urban development and local government unit. Monsoon and other rains now regularly inundate major cities like Dhaka in Bangladesh and Mumbai in India.
She agreed with Rajapaksa that most of this flooding is caused by uncontrolled urban development. “Cities have expanded haphazardly, (but) governments - national and local - have not kept phase with providing services,” she told AlertNet.
Experts warn that the effects of climate change, including more extreme weather patterns, could worsen the problems now faced by cities like Colombo and Dhaka, where millions live or commute daily to work. Limited water resources pose an additional, significant risk to large urban areas, as do rising sea levels in coastal areas.
“Most of these cities can be major contributors to climate change, but they also are at the receiving end of some of the severest impacts,” said Rutu Dave, a climate change specialist at the World Bank Institute in Washington.
EXPLODING POPULATIONS
To make matters worse, many cities are expanding beyond their environmental means.
South Asia’s urban population will double in 25 years, warned Ming Zhang, an urban water and disaster risk management specialist for the World Bank in South Asia.
Dhaka, the Bangladeshi capital, is the fastest-growing city in the region and is home to 37 percent of the country’s population. Nazir Javed, chairman of Dhaka’s Centre for Urban Studies, said unplanned urban growth is already taking a huge toll on parts of the city.
“We don’t have to wait for climate change to come to our city; we have already created it. Dhaka is facing an environmental disaster,” Javed told AlertNet, adding that two of the four rivers that provide water to the city are drying up due to overuse.
The World Bank’s Joshi-Ghani said increasing competition for scarce natural resources is another challenge large cities must contend with. “We are depleting our resources by inefficient use,” she said.
To tackle issues affecting densely populated cities, the World Bank has set up a Mayors’ Task Force on urban adaptation and climate. Soon after the 2009 U.N. climate summit in Copenhagen, it brought together mayors from four cities - Jakarta in Indonesia, Dar es Salaam in Tanzania, Mexico City and San Paulo in Brazil - to share their most pressing needs and possible solutions.
The three key priorities to emerge from that discussion were good urban planning, an integrated institutional network and participation of communities at risk, Joshi-Ghani told AlertNet.
“If we thought about (these), we would be able to address a big chunk of this (problem),” she said.
But as Sri Lankan officials told the World Bank workshop, putting into practice plans that would help avert flooding and other disasters is not easy.
VULNERABLE SLUMS
Almost 43 percent of Colombo’s population lives in shanty towns and slums, according to Indu Weerasoriya, deputy director of the Urban Development Authority (UDA). Many are on low-lying sites that are prone to flooding and have limited access to services like drainage, garbage collection and clean drinking water.
Rajapaksa explained that most of the city’s informal settlements are located on government land bordering lakes, canals, roads and railway tracks.
Moving people from these areas is not only costly, but any resettlement policy has to take into account their livelihoods, education and social networks.
In late 2009, the Sri Lankan government began the delicate process of relocating people from slums, and is currently building 10,000 new housing units, with another 15,000 planned. The UDA has also embarked on a massive project to clear clogged waterways and canals.
The World Bank’s Joshi-Ghani told AlertNet that civil servants and other national decision makers are now becoming more sensitive to the connection between how they plan and run cities, and their ability to prevent disasters.
“There is increasing awareness and commitment to do things differently,” she said.
Amantha Perera is a freelance writer based in Sri Lanka.
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