Centre's decades-old Flood Plain Zoning directive ignored: Gujarat, other states may face Kerala-type devastation

By BN Navalawala*
Incessant rainfall and heavy flooding have caused devastation in large parts of Kerala which now faces the ravages of the worst monsoon floods in 94 years, with 373 dead and more than 1.2 million in relief camps after 2,378 millimetre (mm) of rain over 81 days between June 1 and August 20, 2018 – 42% above normal or three times more than the Indian average for that period, according to data from the India Meteorological Department(IMD).
Now many theories, on such unprecedented flood fury in Kerala, have started being discussed. Amongst the major reasons for such catastrophic incident are: Near absence of Flood Plain Zoning and failure of maintaining the natural drainage system are the two critically important factors.
The basic concept of Flood Plain Zoning is to regulate the land use in the flood plains to restrict the damage caused by floods, which are bound to occur from time to time. Flood Plain Zoning, therefore, aims at determining the locations and the extent of areas likely to be affected by floods of different magnitude/ frequencies and to develop those areas in such a fashion that the damage is reduced to the minimum.
It, therefore, envisages limitations on indiscriminate development of both the unprotected as well as protected areas. In the former case, boundaries of forbidden areas are to be established to prevent indiscriminate growth while in the protected areas development can be allowed which will not involve unduly heavy damage in case the protective measures fail. Although zoning cannot remedy existing situations, it nevertheless can definitely help in minimising flood damage in new developments.
A Model Bill for Flood Plain Zoning was prepared by Central Water Commission (CWC, an apex technical body for water resources in Government of India) way back in 1975 and circulated to all States/Union Territories. The Bill was again circulated in October 1996. In view of lukewarm response from the State Governments towards enactment of Flood Plain Zoning legislation, the Ministry of Water Resources has time and again been impressing upon the State / Union Territory Governments to enact the legislation.
However, the response is quite dismal, as much as only three states, Manipur, Rajasthan and Uttarakhand, have enacted legislations for the Bill and other States are yet to respond. Strangely enough, States of UP and Bihar, which are amongst the worst flood affected states almost every year, have conveyed that Flood Plain Zoning Bill is neither practicable nor implementable.
Further, in a related development, the CWC initiated a programme through Survey of India for carrying out surveys for preparation of flood risk maps to a scale of 1:15,000 with a contour interval of 25 cm for the areas/reaches, identified in a few flood-prone river basins. The work was taken up in a phased manner as per the priorities indicated by the States.
With the available data, the State Governments could then take up preparation of flood risk maps and demarcate areas corresponding to different flood frequencies, for effective implementation of regulations after the enactment of Flood Plain Zoning legislation. The progress on preparation of Flood Plain Zoning/flood risk maps by the State Governments was, however, not satisfactory and the programme of surveys had been discontinued during the Eighth Plan (1992-97). Unfortunately, not much progress was achieved by the State Governments in this respect also.
Another major reason for Kerala situation is the lack of effective implementation to maintain the original carrying capacity of our rivers as well as all natural drainage systems by not ensuring, through adequate legislation, that they are free from any encroachment, siltation and obstructions. With this kind of situation, practically everywhere and more in urban areas, Kerala like situation can happen in any state, including Gujarat.
In this context, it is worthwhile to mention that Flood Plain Zoning is not only necessary in the case of floods by rivers but is also useful in reducing the damage caused by drainage congestion, particularly in urban areas where on grounds of economy and other considerations, urban drainage is not designed for the worst conditions and presupposes some damage during storms, whose magnitude exceeds that for which the drainage system is designed.
Let us take the case of Surat city. Twenty years ago, the safe carrying capacity of flood waters in Tapi River, passing through the city, was 6.5 to 7 lakh cusecs, which is now reduced to 2.5 lakh cusecs only due to man-made interventions, haphazard urbanisation and encroachments in flood plains of the river. More or less similar situation is with Gujarat's other rivers like Sabarmati (in Ahmedabad) and Vishwamitri (in Vadodara).
*Former Secretary to Government of India, Ministry of Water Resources


Anonymous said…
The Sabarmati River Front can become a cause to meander the river course causing un imaginable disaster and irreversible damages.