Events & Issues

New Delhi, 26 October 2009

Controlling Floods

EVOLVE PRAGMATIC STRATEGY

By Dhurjati Mukherjee

The recent floods in Andhra Pradesh and Karnataka raise many questions about the future possibility of its recurrence. According to the Ganga Flood Control Commission, about 40 million hectares of land is flood-prone and the Ganga river basin accounts for half of that. Experts at the Environment & Research Institute (TERI) point out that past data shows areas with prolonged drought have a tendency to get flooded after 4-5 years. And, just weeks ago, both Andhra Pradesh and Karnataka were reeling under severe drought. 

The flooding of the Ganga and the Brahmaputra has become an annual feature. Parts of Bihar and Uttar Pradesh are a constant risk from the Ganga and Kosi which frequently change course, bringing death and destruction in their wake. After Independence, 25 lakh hectares of land were flood-prone but now the figure is double. Bihar alone faces about 22.8 per cent devastation by floods in the country, where the flood affected area is only 16.5 per cent. In Uttar Pradesh, the flood affected areas in 25.1 per cent but only 14.7 per cent is devastated. 

In the case of Bihar, which witnessed floods last year, the river Kosi changed its course leaving around 30 lakh people homeless in north Bihar. In fact, the river has moved westwards by over 100 km .in the past 250 years or so. A section of experts are of the view that the river would revert to its original course but even if that happens the question is whether it would be possible to reclaim the 2.75 lakh acres of farmland that is under water now. It needs to be noted that as the rate of rise of the Himalayas in the Kosi catchments is higher than the channel cut by the river, it has a higher sediment load, leading to the river’s erratic behaviour.

Recently, Dr. R.K. Pachauri, head of the Intergovernmental Panel on Climate Change (IPCC), observed that the erratic behaviour of climate has aggravated the problem and floods are increasing in frequency and intensity. Moreover, a recent IPCC report has warned that “South Asia may be prone to extreme events of flooding owing to climate change”. 

It is abundantly clear that the Centre and the State Governments have virtually failed to control floods. Years of planning and research and setting up of commissions have either failed to deliver the goods or their recommendations have not been adhered to for reasons best known to the Government. Unplanned, unregulated developmental activity in the flood plains of rivers and encroachments in the waterways has led to an increase in flood losses and may cause more flooding in future. 

The National Flood Commission (Rashtriya Barh Ayog) estimated that nearly 40 million hectares of land are prone to flooding. The core of the flood problem lies in the Indo-Gangetic basin, which contains 60 per cent of the total flood prone area and contributes 33 per cent of the total run-off. This area also contains around 40 per cent of India’s total population. The other major flood prone area is the Brahmaputra Valley in the North Eastern part with lower Assam being constantly at risk.

The cropped area affected annually is about 3.5 million hectares and in 1988 was as high as 10 million hectares in 1988, possibly the worst year. On an average, as many as 1529 lives are lost every year due to floods. The total loss on account of flood damage to crops, houses and public utility was estimated to be of the order of Rs 52,659 crores during the period 1953-98 (Chattopadhyay, 2000) which may have touched somewhere around Rs 80,000 to Rs 100,000 crores as of now. 

Another estimate by the Planning Commission in 2002 stated that the annual flood damage was around Rs 1347 crores. However, during 2002-05, the average annual damage flood damage was Rs 3449 crores though how much of this official figure is realistic is not known. Estimates reveal that actual flood losses presently may be anything around Rs 10,000 crores or even more. 

Rivers can no longer be looked as problems of engineering alone. Integrated management is required which means studying the various factors determining the stream flow of a river and generating models to zero in on pressure points. Thus, as a long-term strategy a judicious mix of structural and non-structural measures with a greater emphasis on the latter should form the core of the flood moderation strategy.

Among the structural measures considered has been the construction of dams but not very large ones as is being argued by a section of experts. One is, however, reminded of a significant observation of Prof. D D Kosambi who pointed out way back in 1985: “Neither the engineers nor the (Planning) Commission would consider a more important suggestion namely, that many cheap small dams should be located and built from local materials with local labour. Monsoon water would be considered and two or three crops raised annually on good soil that now yields only one”.

The Task Force for flood management and erosion control recommended that in high flood-prone areas, flood control should be given overriding consideration in reservoir regulation policy even at the cost of sacrificing some irrigation or power projects. It has also suggested that adequate flood cushion should be provided in water storage projects, wherever possible, to facilitate better flood management.

It is significant that the Task Force has aptly recommended that even in reservoirs constructed for power and irrigation, operational rules need to be framed in such a way that effective flood moderation becomes feasible. In the National Water Policy 2002 document, it has been stipulated that there should be a master plan for flood control and management for each flood-prone basin and it is now imperative that the plan should be scrupulously followed to save human lives.

Among the non-structural measures, the emphasis should be on watershed management and massive tree planting in the upper catchments of the rivers originating from the hills. Also rainwater harvesting has been suggested as a way of controlling floods. Attempts have been made to create water bodies which would store water, either under the ground or in talwars.

Efficient management of flood plains, flood-proofing including disaster preparedness and flood forecasting and warning should be the other measures to be given priority. Installation of modern and effective flow forecasting and warning network in the catchment areas of reservoirs for real time forecasting and to ensure maximum possible moderation of the anticipated flood peaks is imperative at this juncture.

Coordination and cooperation with the basin countries like Nepal, Bhutan and even China would also go a long way in controlling floods. What is most important, however, is the political will as also a multi-disciplinary approach that covers not only technology but also social, economic and environmental considerations in evolving a pragmatic strategy to counter floods, which is possibly the most devastating and recurring natural disaster in the country. --INFA

 
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