Floods in India

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Every year floods cause massive damages to entire communities, property, infra-structure, business enterprises, government centres, crops, wildlife, and natural resources. As per UN global assessment report (GAR)2015 India's average annual economic loss due to disasters is estimated to be $9.8 billion. This includes more than $7 billion loss on account of 2013 some 6,500 people died due to floods in India. To mitigate part of the risk communities across India can help governments with activities like afforestation, reforestation, floodplain zoning, embankments, developing artificial ground water recharging points, restoration of wetlands and water bodies. These activities can lead to greater infiltration of rain water to increase the ground water table and avoid acceleration of run-off which raises the water level in rivers. Part of the problem which caused Chennai and Mumbai floods was obstruction of free flow of water caused by chocked drainage system. Littering is significant cause of chocked drainage system. Communities can help by running anti littering drives and keep neighbourhoods clean.

Following climate and environmental factors analysis on is worth discussion by community activists for evaluation and correction of Government policies.

2005 Mumbai floods

Antiquated drainage system: The present storm-water drainage system in Mumbai was put in place in the early 20th century and is capable of carrying only 25 millimetres of water per hour which was extremely inadequate on a day when 993 mm of rain fell in the city. The drainage system was also clogged at several places.Only 3 'outfalls' (ways out to the sea) are equipped with floodgates whereas the remaining 102 open directly into the sea for more than 24 hours. As a result, there is no way to stop the seawater from rushing into the drainage system during high tide. In 1990, an ambitious plan was drawn to overhaul the city's storm water drainage system which had never been reviewed in over 50 years. A project costing approximately 600 crore rupees was proposed by UK based consultants hired by the Brihanmumbai Municipal Corporation to study the matter. Implementation of the project would have ensured that rainwater did not flood the streets of Mumbai. The project was planned to have completed by 2002 and aimed to enhance the drainage system through larger diameter storm water drains and pipes, using pumps wherever necessary and removing encroachments. The project, if implemented would have doubled the storm water carrying capacity to 50 mm per hour. The BMC committee had rejected the proposed project on the grounds that it was "too costly". These were few of the drawbacks due to which the city suffered so gravely.

Uncontrolled, unplanned development in Northern Suburbs: Development in certain parts of Mumbai is haphazard and buildings are constructed without proper planning. The drainage plans in northern suburbs is chalked out as and when required in a particular area and not from an overall point of view.The Environment Ministry of the Government of India was informed in the early 1990s that sanctioning the Bandra-Kurla complex (a commercial complex in northern Mumbai) was leading to disaster. No environment clearance is mandatory for large urban construction projects in northern Mumbai. Officials in the environment ministry claimed that it was not practical to impose new guidelines with retrospective effect "as there are millions of buildings".

Destruction of mangrove ecosystems: Mangrove ecosystems which exist along the Mithi River and Mahim Creek are being destroyed and replaced with construction. Hundreds of acres of swamps in Mahim creek have been reclaimed and put to use for construction by builders. These ecosystems serve as a buffer between land and sea. It is estimated that Mumbai has lost about 40% of its mangroves between 1995 and 2005, some to builders and some to encroachment (slums). Sewage and garbage dumps have also destroyed mangroves. The Bandra-Kurla complex in particular was created by replacing such swamps. The most acclaimed Mindspace CBD (INORBIT MALL) in Goregaon & Malad has been built by destroying a large patch of mangroves in Maharashtra.

2013 Uttarakhand floods

A study by Utah State University analysed the natural and anthropogenic influences on the climate anomalies using simulations, and found that (a) northern India has experienced increasingly large rainfall in June since the late 1980s, (b) the increase in rainfall appears to be associated with a tendency in the upper troposphere towards amplified short waves, and (c) the phasing of such amplified short waves is tied to increased loading of green-house gases and aerosols. In addition, a regional modelling diagnosis attributed 60–90% of rainfall amounts in the June 2013 event to post-1980 climate trends.

Unprecedented destruction by the rainfall witnessed in Uttarakhand state was also attributed, by environmentalists, to unscientific developmental activities undertaken in recent decades contributing to high level of loss of property and lives. Roads constructed in haphazard style, new resorts and hotels built on fragile river banks and more than 70 hydroelectric projects in the watersheds of the state led to a "disaster waiting to happen" as termed by certain environmentalists.The environmental experts reported that the tunnels built and blasts undertaken for the 70 hydro electric projects contributed to the ecological imbalance in the state, with flows of river water restricted and the streamside development activity contributing to a higher number of landslides and more flooding.

2014 Kashmir floods

As was the case with some of the previous extreme rainfall events, the scale of disaster in J&K has been exacerbated by unplanned development – especially on the riverbanks. In the last 100 years, more than 50 per cent of the lakes, ponds and wetlands of Srinagar have been encroached upon for constructing buildings and roads. The banks of the Jhelum river have been taken over in a similar manner, vastly reducing the river’s drainage capacity. Naturally, these areas have suffered the most.

2015 Chennai floods

Unregulated urban planning and illegal construction: According to research conducted by CSE, Chennai had over 600 lakes in the 1980s, but a master plan published in 2008 showed only a fraction of them to be in a healthy condition. State records have shown the total area of 19 major lakes shrank from 1,130 hectares in the 1980s to around 645 hectares in the early 2000s, reducing their storage capacity. Drains carrying surplus water from tanks to other wetlands have also been encroached upon, while city storm water drains are clogged and require immediate desilting. Chennai has only 855km of stormwater drains against 2,847km of urban roads, resulting in flooding after even a marginally heavy downpour.

Improper design and maintenance of drainage systems: Extensive and costly projects begun in 2013 to desilt city storm drains had been ineffectively conducted. The drains themselves were reported to have been shoddily built and improperly designed. A 2014 CAG report revealed that a diversion channel from the Buckingham canal near Okkiyum Maduvu to the sea (a drain project under the JNNURM scheme) could have saved South Chennai from flooding; the government, however, dropped the ₹100 crore scheme, which, had it been completed, would have drained floodwater from southern neighbourhood at a rate of 3,500 cubic feet per second. The 2014 CAG report said the defective planning of flood control projects caused delays and increased costs, defeating the objective of the scheme. "The fact is that alleviation of inundation of flood water in Chennai city remains largely unachieved", it said.

Climate-change related: In 2006, a study by the Indian Institute of Tropical Meteorology (IITM) in Pune showed extreme precipitation events had increased in frequency and intensity in India over the period from 1950 to the 2000s; while CSE’s climate change experts recommend detailed attribution studies to establish more links between the Chennai floods and climate change, they did state that existing scientific studies establish a possible connection.

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