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Flood-Prone Areas | Requisites for a Coordinated Response

Flood prone areas of India

The tragedy of the monsoons is often floods and landslides — 2017 was no different. The Government of India claims that by July 28, 2017, a period by when the monsoons had made their onset over most of India, about 600 deaths have occurred across the country due to floods and landslides. The government made this announcement during the declaration of compensation to the tune INR 500 crores for flood victims in Gujarat, where heavy showers and subsequent flooding claimed about 100 lives (S.K. Ramchandran, 2017). Flash flooding also killed 6 people in Jammu & Kashmir in Thatri town in Doda district, with many people feared missing due to the flow of debris.

The flood prone state of Assam, where floods have claimed about 76 lives with about 16 lakh people affected, has witnessed about 2 lakh ha of agricultural land being inundated by the deluge (N. Mitral, 2017). The Assam Government seeks INR 3,000 crores grants from the Centre as interim relief, much above the Rs 500 crore that was offered. The Assam Government also announced its ambitious plans to build a 5,000 km long embankment under the policy infrastructure provided by the Prime Minister’s special flood and erosion control programme. Among the flood prone states, Bihar has been till data out of the flood ambit, as it has received light to moderate rainfall so far accompanied with generally cloudy skies.

Cities most prone to extreme rain and flood ‘study reveals’

Flood-Prone Areas in India

Out of the total geographical area of 329 million ha (mha) in India, over 40 mha is flood prone (NDMA, 2017). The Government of India identifies certain areas in India as chronically flood prone and institutes measures to deal with their problems and also formulates development policies in these areas with regard to the possibility of a flooding event. The most flood-prone areas include the Indo-Gangetic plains including parts of Uttar Pradesh, Bihar and West Bengal; the Brahmaputra plains including large parts of Assam; Gujarat; Maharashtra; Odisha; Seemandhra and Telangana.

Fig: Areas Marked in Red are Flood Prone Areas of India

Source: CWC

Flood Monitoring the Remote Sensing Way

Flood Mitigation

Floods being the most common natural disaster in India, the Central Water Commission (CWC), GoI began the flood forecasting service in 1958 with the purpose of the issuing of water level forecasts for river Yamuna for Delhi. The year 1969 witnessed the setting up of a Flood Forecast and Warning Organization by the CWC to set up forecasting sites for inter-state rivers at various locations in India expected to be flood prone areas. These forecasts were based on checking the water levels of major water bodies such as rivers and establishing water levels that were classified under various categories. An important part of this exercise regarding flood forecasting began with checking for whether the levels of surface water in the water body had crossed the ‘warning level’, after which the water body was monitored as a possibility for a flood risk. This monitoring system based on monitoring stations formed the basis for much of flood mitigation in consonance with state resources for a long period before a shift was observed in thought in India over flood mitigation policy. The CWC utilizes a system of classification of floods depending on the severity of the flooding event as (CWC, 2016) –

  1. Low flood – when the water level crosses the warning level but is below the danger mark.
  2. Moderate flood – when the water level is above the danger mark but less than 0.50 m below the Highest Flood level (HFL) of the site.
  3. High flood – when the water level at the site is between the HFL and 0.50 m below it.
  4. Unprecedented flood – when the water level crosses the HFL at any forecasting site until the event, which leads to a special ‘Red Bulletin’ being issued by the CWC for various agencies.

The Chennai 2015 Floods

 

Widespread destruction of life and property over the years has led to various structural and non-structural measures taken by central and state governments for flood mitigation, and considerable protection is provided to people affected or likely to be affected by flooding events. The trend in policy thought in India has been to institute a techno-legal regime that serve to make structures flood-proof and techno-legal developmental instruments that can regulate activities in flood prone areas such that damage caused due to flooding is minimized.

This involves improving the technological efficiency of flood forecasting and warning systems and providing a Decision Support System (DSS) based on scientific findings and the latest global technological developments. The National Disaster Management Authority (NDMA) recommends a step-by-step process for forming a strong policy regime on flooding events in flood-prone areas. This involves –

  • Capacity development and improvement of flood response mechanisms by central and state governments for taking preventive and mitigatory measures at the pre- during- and post-flood stages.
  • Minimising flood-risk and losses of life and property through a 3 phase process involving firstly identification and review of flood prone areas, secondly formulation of schemes for flood forecasting expansion and modernization, and thirdly implementation of all activities.

Identification and review activities for flood prone areas involve preparing flood vulnerability maps and flood forecasting, use of technological improvements in collection and evaluation of meteorological data, and warning technology for flood prone areas such as flood hazard evaluation with the help of satellite data. The scheme related activities include site-specific drainage improvement with the help of instruments such as building embankments, periodic review of dams and reservoirs for water levels and drainage, conducting studies on river erosion, and improving existing drainage networks. The activities pertaining to enforcement include enforcement of flood plain zoning regulations, catchment area treatment for dams, inspections of water bodies including areas such as those of embankments and other structures, and building national and international co-operation for the management of water resources.

Flood hazard mitigation also requires joint formulation of forecasts to prevent ambiguity that could have a ripple effect on the ground situation. Also development activities have to be regulated to avoid features such as drainage congestion, soil testing techniques applied for preventing rise in water levels due to erosion and siltation, etc. In all, an integrated approach is necessary such that a scientific basis of having early warning systems for flooding in flood-prone areas is present, and the response in terms of management of flooding disasters is adequate such that have an early warning system that provides for a more co-ordinated response from the administrative machinery.

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