Chennai floods due to impact of climate change: CSE

Paris An Indian green body on Friday said that the floods in Chennai are an impact of climate change and the unprecedented deluge that the city has witnessed is a reminder of increasing frequency of such freak weather events across the Indian subcontinentThe Centre for Science and Environment CSE said that Chennai could have fared better if it had protected and preserved its natural water bodies and drainage channelsWe have repeatedly drawn attention to the fact that our urban sprawls such as Delhi Kolkata Mumbai Chennai Srinagar and others have not paid adequate attention to the natural water bodies that exist in them said CSE director general Sunita NarainIn Chennai each of its lakes has a natural flood discharge channel which drains the spillover 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 she saidShe said that Down To Earth the science and environment fortnightly that CSE helps publish had earlier reported on the destruction of wetlands in ChennaiCSE said that a number of cities including Chennai are both waterscarce as well as prone to floodingBoth problems are related excessive construction which leads to poor recharge of groundwater aquifers and blocking of natural drainage systems While Chennai has been struggling to meet its water needs and has been even desalinating sea water at a huge expense it allowed its aquifers to get depleted said Sushmita Sengupta deputy programme manager with CSEs water teamCSEs 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 them are in healthy conditionAccording to records of the states Water Resources Department the area of 19 major lakes has shrunk from a total of 1130 hectares ha in the 1980s to around 645 ha in the early 2000s reducing their storage capacityThe 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 and Chennai has only 855 kms of stormwater drains against 2847 kms of urban roadsCSE said that the rains in Chennai have broken a 100year record 374 mm in just 24 hoursIn November the city had received 1218 mm of rain which was almost three times more than the average the city receives 407 mm it saidScientific research has already linked such intense weather phenomena to a changing climate and IPCCs fifth Assessment Report clearly says that frequency and intensity of such excessive rainfall events will increase in futureCSE said that a 2006 study by the Indian Institute of Tropical Meteorology IITM in Pune had said that extreme precipitation events were increasing in frequency and intensity in India during the period 1950 to the 2000sCSEs climate change experts point out that while detailed attribution studies needed to be done to find out more links between the Chennai catastrophe and climate change existing scientific studies do establish the possibility of a connection