India: Flooding in Tamil Nadu Highlights Water Management Problems

18 November 2015 FDI Team

Recent flooding in the Indian state of Tamil Nadu has left its capital, Chennai, in a state of crisis, highlighting the limited effectiveness of the state’s water policies and infrastructure.


A low-pressure trough in the Bay of Bengal has caused week-long heavy rainfall and flooding to occur in Tamil Nadu. As a result, many areas in Chennai have become water-logged, transport facilities have been disrupted and government schools and colleges closed for three days. Over one thousand people in North Chennai were evacuated and reports claim that over 55 people have died as a result of the rainfall.


The Tamil Nadu Government has been criticised for its “slack” flood relief assistance. The state’s Bharatiya Janata Party chief, Tamilisai Soundararajan, claims that the government has failed to construct adequate drainage facilities to cope with heavy rainfall. According to environmentalists, poor hydrological planning in Chennai contributed significantly to the flooding in the city. Contour levels are an important aspect in the design and location of stormwater drainage systems but have been ignored by planning officials in Chennai. Inadequate hydrological planning has also adversely affected the natural drainage of heavy rainfall. The development of high-rise buildings in areas prone to water-logging, including wetlands, has disturbed the flow of rainwater and has contributed to the flooding.

The government failed to adequately de-silt stormwater drains before the monsoon season, leaving clogged drains that contributed to the flooding. A ban on manual scavenging has no doubt improved sanitation and hygiene practices but has contributed to the build-up of silt. The government experienced a delay in obtaining machinery needed to clean the drains. Of the contractors willing to perform the task, some dumped the silt near the drains, causing them to re-clog with heavy rainfall. Not only is the city now subject to large financial loss due to flood damage, but its failure to adequately prepare for the monsoon season has resulted in public distress.

Instead of disposing of waste away from the city, private operators have used the coverage of the rainfall to dump sewage on deserted roads and in open spaces in Chennai. Sewage has already discharged through stormwater drains into some open flooded areas, contaminating free-flowing rainwater, and now private operators are adversely contributing to the pollution. The illegal dumping of waste could pose the significant risk of contaminating freshwater sources and create a public health hazard.

Chennai’s rainwater harvesting (RWH) structures, installed more than a decade ago, have posed problems to water management in Tamil Nadu. A majority of RWH structures in Chennai have not been adequately maintained, with many non-operational due to clogging. Of the operational RWH structures, only those located on terraces preserve a small amount of water. Although the heavy rainfall has increased the water level in Tamil Nadu’s reservoirs, the intensity of the downpours has made it difficult for Chennai’s RWH structures to collect water at full capacity. Neglected RWH structures have failed to maximise rainwater storage and to alleviate the pressure on stormwater drains during flooding.

The Tamil Nadu Government is in need of effective drain-system management to enhance the state’s response during the monsoon season. Chennai would also benefit from a renewed policy approach that promotes the repair of existing RWH structures and the installation of new systems for all residents. Illegal dumping of waste by contractors is not a new phenomenon, however. Instead of dumping under the cover of darkness, the current contractors have used the heavy rainfall to dispose of waste during daytime. Strict enforcement against this practice must be adopted by the government to eliminate the risk to public health that this creates. Seasonal heavy rainfall is not uncommon in Tamil Nadu but measures must be adopted to better manage the state’s water policy for the future.

Madeleine Lovelle
Research Analyst
Global Food and Water Crisis Research Programme

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