Reality of floods
In 2013, a multi-day cloudburst in Uttarakhand caused devastating floods, killing more than 5,000 people. A year later, Kashmir suffered disastrous deluge due to torrential rainfall. Thousands were displaced and more than 500 people were killed in all. At the end of 2015, Chennai had its brush with an equally catastrophic flood that paralysed the city. The year 2016 saw Assam and Madhya Pradesh grapple with the reality that floods of massive intensity have become the new normal for India.
While it is convenient to push the blame to extreme weather events for unprecedented rains, not all of it is of nature’s doing. For instance, rains could cause so much havoc in Uttarakhand because the state had already witnessed indiscriminate developmental activities carried out in the ecologically fragile regions of the state. Chennai, which is no stranger to cyclonic storms and heavy rains, especially during the annual northeast monsoon in November–December, saw the worst flood in its history. In its bid to expand, the city has been encroaching upon its rivers, sacrificing wetlands to accommodate development and eating into the marshlands for developing public infrastructure.
On this note, let’s take a look at the reasons pushing urban floods and the price we are paying for not reading the signs.
An urban nightmare
The memories of unprecedented floods in Mumbai, Srinagar, and Chennai are still fresh. Ignored as a 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.
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 wasteland. A city’s lake is its lifeline.
Shrinking water bodies push urban floods
Lakes and wetlands are an important part of the urban ecosystem. They perform significant environmental, social, and economic functions ranging from being a source of drinking water, recharging groundwater to acting as sponges, supporting biodiversity and providing livelihoods. Their role becomes even more critical in today’s context when cities are facing the challenge of rapid unplanned urbanisation.
Their numbers are declining rapidly. For example, in the 1960s Bangalore had 262 lakes, now only 10 hold water. Similarly, in 2001, 137 lakes were listed in Ahmedabad city, and construction work had started on 65 of them. Another example exhibiting this increasing loss of urban water bodies is Hyderabad. In the last 12 years, Hyderabad has lost 3,245 ha of its wetlands.
The National Disaster Management Guidelines: Management of Urban Flooding report, published by the National Disaster Management Authority (NDMA) in 2010, says that concretisation is a major problem in many cities and towns. According to the Union Ministry of Urban Development (MoUD), 31 percent of the country was urbanised in 2011. The ministry says almost 50 percent of the country will be urbanised by 2050. MoUD data also suggests a 54 percent increase in the number of cities and towns between 2001 and 2011.
Natural streams and watercourses, formed over thousands of years due to the forces of flowing water in the respective watersheds, have been altered because of urbanisation. “As a result of this, the flow of water has increased in proportion to the urbanisation of the watersheds. Ideally, the natural drains should have been widened to accommodate the higher flows of stormwater. But on the contrary, there have been large-scale encroachments on the natural drains and the river flood plains. Consequently, the capacity of natural drains has decreased, resulting in flooding,” says the NDMA report.
(Views expressed are strictly those of Down to Earth.)