An urban nightmare

The memories of unprecedented floods in Mumbai, Srinagar and Chennai are still fresh. Ignored as sporadic or once-in-a-while event, urban floods have become regular, and increasingly devastating. The floods repeatedly draw our attention to only one fact: our urban sprawls have not paid adequate attention to the natural water bodies that exist in them. A case in point is Chennai, where each of its lakes has a natural flood discharge channel which drains the spill over. But we have built over many of these water bodies, blocking the smooth flow of water. We have forgotten the art of drainage. We only see land for buildings, not for water. And the result is in front our eyes.

An urban water body provides some crucial services such as groundwater recharge and flood management. If you ask the obvious question of how construction was permitted on the wetland, you will get a not-so-obvious response: wetlands are rarely recorded under municipal land laws, so nobody knows about them. Planners see only land, not water, and builders take over.

A number of cities including Chennai are both water-scarce as well as prone to flooding. Both problems are related—excessive construction which leads to poor recharge of groundwater aquifers and blocking of natural drainage systems. The city witnessed severe floods in 2015 when the entire city got completely submerged under water after it rained for a few days.

Floods have become a chronic problem in Chennai (Photo: REUTERS)

Delhi-based non-profit Centre for Science and Environment’s research shows that Chennai had more than 600 water bodies in the 1980s, but a master plan published in 2008 said that only a fraction of the lakes could be found in a healthy condition. According to records of the state’s Water Resources Department, the area of 19 major lakes had shrunk from a total of 1,130 hectares (ha) in the 1980s to around 645 ha in the early 2000s, reducing their storage capacity. The drains that carry surplus water from tanks to other wetlands have also been encroached upon.

The analysis also shows that the stormwater drains constructed to drain flood waters are clogged and require immediate desiltation. Chennai has only 855 km of stormwater drains against 2,847 km of urban roads. Thus, even a marginally heavy rainfall causes havoc in the city. Explaining the problem of pollution, the City Development Plan says: “The waterways of Chennai… receive flood discharge only during the monsoon season; the rest of the year these act as carriers of wastewater from sewage treatment plants and others.”

So Chennai needs to do what all cities must—undertake a detailed survey of the wetlands and then bring every water body and its catchment under legal protection. The Wetlands Conservation and Management Rules issued by the Union Ministry of Environment and Forests and Climate Change are toothless and meaningless. What is needed is to ensure that city development rules include a comprehensive list of water bodies and their catchment. Any change of this land use should not be permitted. Even this will not be enough unless the city values the water this land gives.

The Central government should provide funds for water supply to only those cities that have brought their own water sources under protection. The cities must show they have optimised local water potential before claiming access to water from far away sources. This will reduce the cost of supply. The city can invest the saved money in treating sewage, which pollutes the lakes and ponds in the first place. It is this vicious cycle that needs to be broken.

It is time we realised that a water body is not an ornamental luxury or a wasted land. A city’s lake is its lifeline