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Floods have been recurrent phenomenon in many parts of India, causing loss of lives and public property and bringing untold misery to the people, especially those in the rural areas. There is also a larger economic impact, as they derail economic activities, thus affecting growth. Indian continent has peculiar climatic conditions since it has floods in some parts whereas drought in other parts. Over the years, several expert Committees have studied the problems caused by floods and suggested various measures for their management to the Government. However, despite the various steps undertaken over the last five decades, the trend of increasing damage and devastation brought by floods has posed a challenge to the Government as well as to the people. The approaches to flood management presently exercised in India also need to give a re-look to have an integrated strategy for policy and management related to floods.
River Systems and Associated Flood Problems
The rivers in India can be broadly divided into the following four regions for a study of flood problem.
(1) Brahmaputra Region;
(2) Ganga Region;
(3) North West Region ; and
(4) Central India and Deccan region.
Brahmaputra River Region:
This region consists of the rivers Brahmaputra & Barak and their tributaries covering seven states Assam, Arunachal Pradesh, Meghalaya, Mozoram, Nothern parts of West Bengal, Manipur, Tripura and Nagaland. The catchments of these rivers receive very heavy rainfall ranging from 110 cm. to 635 cm. a year which occurs mostly during the months of May / June to September. As a result, floods in this region are severe and quite frequent. Further, the rocks of the hills, where these rivers originate are fragile and susceptible to erosion thereby causing exceptionally high silt charge in the rivers. In addition, the region is subject to severe and frequent earthquakes which cause numerous landslides in the hills and upset the regime of the rivers. The predominant problems in this region are the flooding caused by spilling of rivers over their banks, drainage congestion and tendency of some of the rivers to change their courses. In recent years, the erosion along the banks of the Brahmaputra has assumed serious proportions.
Ganga River Region:
The river Ganga and its numerous tributaries, of which important ones are the Yamuna, the Sone, the Ghaghra, the Gandak, the Kosi and the Mahananda, constitute this river region. It covers ten states of Uttaranchal, Uttar Pradesh in its basin area , Jharkand, Bihar, South and Central parts of West Bengal, parts of Haryana , Himachal Pradesh, Rajasthan, Madhya Pradesh and Delhi. The normal annual rainfall in this region varies from 60 cm to 190 cm of which more than 80% occurs during the south west monsoon. The rainfall increases from West to East and from South to North.
The flood problem is mostly confined to the areas on the northern bank of the river Ganga. The damage is caused by the northern tributaries of the Ganga by spilling over their banks and changing their courses. Even though the Ganga is a mighty river carrying huge discharges of 57,000 to 85,000 cumec (2 to 3 million cusec), the inundation and erosion problems are confined to relatively few places. In general, the flood problem increases from the West to the East and from South to North.In the North Western parts of the region and some eastern parts, there is the problem of drainage congestion.
The flooding and erosion problem is serious in the States located in the downstream.In recent years some States which were not traditionally flood prone have also experienced some incidents of heavy floods.
North West River Region:
The main rivers in this region are the Sutlej, the Beas, the Ravi, the Chenab and the Jhelum, the tributaries of Indus, all flowing from the Himalayas. These carry quite substantial discharge during the monsoon and also large volumes of sediment. They change their courses frequently and leave behind tracts of sandy waste. The region covers the State of Jammu and Kashmir, Punjab and parts of Himachal Pradesh, Haryana and Rajasthan.
Compared to the Ganga and the Brahmaputra river region, the flood problem is relatively less in this region. The major problem is that of inadequate surface drainage which causes inundation and water logging over vast areas.
Central India and Deccan Region:
The important rivers in this region are the Narmada, the Tapi , the Mahanadi, the Godavari, the Krishna and the Cauvery. These rivers have mostly well defined stable courses. They have adequate capacity within the natural banks to carry the flood discharge except in the delta area. The lower reaches of the important rivers on the East Coast have been embanked, thus largely eliminating the flood problem.
Flood Prone Areas in India
National Flood Commission (RBA) -1980 assessed the total flood prone area in the country as 40 m.ha which included the unprotected flood area of 33.516 m ha and the balance as protected area. Subsequently, the Working Groups on Flood Management for X and XI Plans assessed the flood prone area in the country as 45.64 m ha.
Statutory Provisions about Flood Management
The subject of flood control, unlike irrigation, does not figure as such in any of the three legislative lists included in the Constitution State list,Union list and concurrence list of India. However, Drainage and Embankments, are two of the measures specifically mentioned in entry 17 of List II (State List), reproduced below:
“Water, that is to say, water supplies, irrigation and canals, drainage and embankments, water storage and water power subject to the provision of entry 56 of List I(Union List).”
Entry 56 of List I (Union List) reads as follows:-
“Regulation and development of inter-State rivers and river valleys to the extent to which such regulation and development under the control of the Union is declared by Parliament by law to be expedient in the public interest..”
It may thus be seen that the primary responsibility for flood control lies with the States. A number of States have already enacted laws with provisions to deal with matters connected with flood control works. Therefore, the subject “ flood management” falls within the purview of the States. The schemes for flood control are planned, investigated and implemented by the States as per priorities within the State with their own resources and the role of central government is technical, advisory, catalytic and promotional in nature.
Existing Flood Management Mechanisms in India
In India, a two tier system of flood management exists as briefly described below:
State Level Mechanism - The State Level Mechanism includes the Water Resources Departments, State Technical Advisory Committee and Flood Control Board. In some States, the Irrigation Departments and Public Works Departments look after flood matters.
Central Government Mechanism – The Union Government has set up following organizations and various expert committees to enable the State Governments in addressing flood problems in a comprehensive manner:
Central Water Commission (CWC) – The Government of India set up Central Water Commission as presently named in 1945 for achieving the goal of furthering and promoting measures of flood control, conservation and utilization of water resources through out the country in the areas of beneficial uses, irrigation and hydropower generation, flood management and river conservation. As a national apex engineering organisation in the field of water resources development, the CWC with its vast experience gained in its strides towards progress in more than six decades, has developed considerable know-how in planning, investigation, management and design of water resources development schemes and made valuable contribution in the country’s remarkable progress in this field besides sharing the expertise with developing nations of the world.
Brahmaputra Board – The Government of India set up Brahmaputra Board under Brahmaputra Board Act, 1980 (46 of 1980) under the then Ministry of Irrigation ( now Ministry of Water Resources) The jurisdiction of Brahmaputra Board includes all NEStates of North East region States in Brahmaputra and Barak Basin. The main functions of Brahmaputra Board are as under :
- Survey and investigations in Brahmautra and barak valley.
- Preparation of master plans to control floods, bank erosion, improvement of drainage system.
- Preparation of DPRs for dams and other projects
- Standard specifications for construction operation and maintenance of dams.
- Construction of multipurpose dams and maintenance thereof.
- Any other function for implementation of Brahmaputra Board Act-1980.
Brahmaputra Board prepared master plans for the flood management for river Brahmaputra and Barak.Besides this, the Board has undertaken survey and investigations for preparation of master plans for tackling the problems of flood, erosion and drainage congestion including DPRs for multipurpose projects.
Ganga Flood Control Commission - The Ganga Flood Control Commission (GFCC) was set up by Government of India in 1972 for preparation of comprehensive plan of flood control for Ganga Basin and to draw out a phased coordinated programme of implementation of works and monitoring & appraisal of flood management schemes of Ganga basin States. The GFCC has prepared comprehensive plans of flood management of the 23 sub-basins in the Ganga Basin besides drawing out a phased programme of implementation of these works to proper standards, examination and monitoring of various flood management schemes in the Ganga Basin States.
Farakka Barrage Project Authority – The Farakka Barrage Project Authority carry out anti-erosion and river bank protection works in its jurisdiction in near river vicinity of the Barrage..
National Disaster Management Authority (NDMA) - For prevention and mitigation effects of disasters including flood disasters and for undertaking a holistic, coordinated and prompt response to any disaster situation, the Government of India has set up a National Disaster Management Authority (NDMA) in 2005 under the Chairmanship of Hon’ble Prime Minister of India. The functions of the NDMA are :
(i) lay down policies on disaster management;
(ii) approve national Plan;
(iii) approve plans prepared by the Ministries or departments of the Government of India in accordance with the National Plan; (iv) lay down guidelines to be followed by the State Authorities in drawing up the State Plan;
(v) lay down guidelines to be followed by the different Ministries or departments of the government of India for the purpose of integrating the measures for prevention of disaster or the mitigation of its effects in their development plans and projects;
(vi) coordinate the enforcement and implementation of the policy and plan for disaster management;
(vii) recommend provision of funds for the purpose of mitigation;
(viii) provide such support to other countries affected by major disasters as may be determined by the central Government;
(ix) take such other measures for the prevention of disaster, or the mitigation, or preparedness and capacity building for dealing with the threatening disaster situation or disaster as it may consider necessary;
(x) lay down broad policies and guidelines for the functioning of the National Institute of Disaster Management.
The NDMA has issued guidelines in January, 2008 for management of floods and the roles of various Central and State agencies have been specified for preparation of flood mitigation plans and taking relief measures during flood disasters.
Government’s Initiatives and Policies on Floods
After the unprecedented floods of 1954, the Government of India took several initiatives and constituted a number of Committees to study the problem of floods in the country.
Recommendations Of Expert Committees On Flood Management
A brief account of the recommendations of some of the important expert committees are as follows.
Policy Statement - 1954
Following the unprecedented floods of 1954, the Union Minister for Planning, Irrigation and Power, placed before the Parliament on 3rd September, 1954, two statements namely "Floods in India - Problems and remedies" and "The Floods in the country".The objective unequivocally set, in the policy statements, was to rid the country from the menace of floods by containing and managing floods and thus solving the problem.
In the supplementary statement placed before the Parliament on the 27th July, 1956, the above optimistic note changed a little, stating “We shall, however, be able to curb and confine the floods, more and more and do all that is possible to save ourselves from the harm and the devastation that they bring”. Simultaneously, a statement on the flood situation and flood control programme was laid before the Parliament. In this Statement, it was, pointed out that absolute immunity from flood damage was not physically possible even in the distant future.
High Level Committee On Floods – 1957 & Policy Statement of 1958
A High Level Committee on floods submitted its report in December, 1957, and this was considered by the Central Flood Control Board in its seventh meeting held in May, 1958. Some of their important recommendations are
(i) Absolute or permanent immunity from flood damage is not physically attainable by known methods of flood control. Flood plain zoning, flood forecasting and warning, and like measures should, therefore, be given due importance, particularly as these do not require large capital investment.
(ii) Flood control schemes should fit in with other water related plans to the extent feasible.
(iii) Future multi-purpose project should consider flood control aspects simultaneously.
(iv) Effects of embankments on river regime be considered, before approving such proposals.
(v) In general, embankments are satisfactory means of flood protection when properly designed, executed and maintained, but a suitable combination of this method with other methods such as storage dams, detention basins, etc. is usually more efficient and should be adopted as resources permit.
(vi) Priorities for soil conservation work relating to flood control should be as under:-
(a) Catchment areas of multi-purpose dams.
(b) Himalayas with their foothills.
(c) Indo-Gangetic plain and
(d) Deccan plateau.
vii) Works relating to watershed management prioritized. Work commenced in a catchment should not be left incomplete to take up work in other catchments.
(viii) The following order of priority in general is recommended:-
(a) Emergent schemes,
(b) Continuing schemes,
(c) Schemes for the protection of important urban and industrial communities.
(d) Schemes which would help in augmenting flood protection in the country.
(e) Schemes which combine other beneficial utilization of waters.
Another policy statement placed in Parliament in 1958 also emphasises that while substantial diminution of flood related distress is possible, immunity against flood is impracticable.
National Flood Commission (Rashtriya Barh Ayog) – 1980.
The National Flood Commission (R.B.A.) submitted its comprehensive report in March,1980. This contained a total of 207 recommendations covering the entire gamut of flood problem in the country. Some of the important recommendations are given below.
- Data collection for providing information on their long term performance and their impact on various socio-economic factors.
- Legislation and enforcement by States to prevent unauthorized river bed cultivation and encroachments into drains etc.
- Separate reporting of flood damage for (i) Unprotected areas (ii) Protected areas and (iii) Areas situated between the embankments.
- Legislation for management of flood plains.
- A comprehensive dynamic and flexible approach to the problem of floods as a part of a comprehensive approach for the utilization of land and water resources.
- Priority for measures to modify the susceptibility of life and property to flood damage.
- Priority for completion of continuing schemes.
- Adequate funds for maintenance.
- States to enact legislation amending section 17 (II) of land acquisition act, to make the existing provisions for emergent situations, as applicable for flood control works.
- Intensifying studies on sedimentation of reservoirs.
- Forming a national council for mitigating disaster.
Expert Committee to Review the Implementation of the Recommendations of National Flood Commission-2003 (R Rangachari Committee)
An Experts Committee under the Chairmanship of Shri R Rangachari was set up by Ministry of Water Resources, Government of India in October 2001 to review the implementation of recommendation of National Flood Commission.
The Committee suggested emphasis on 25 recommendations out of 207 and summed up its views as follows:
- Flood damage assessment, from year to year, is not done realistically or on scientific basis as per RBA recommendations, due to collateral reasons, which are surmised but not expressed. This needs corrective steps.
- Lack of representative, scientific and credible post-project performance evaluations of past flood management works is a serious handicap.
- Unabated and unplanned intrusion into the flood plains and river beds, sometimes with the approval or acquiescence of Government has now reached alarming dimensions. If this is not managed, flood losses will continue to mount.
- RBA has made a number of recommendations on the future approach and the planning and implementation thereof. Most of these have not been implemented or at the best partially implemented. They will have to be kept in view as part of future approach.
- The international dimensions of flood management as an integral part of Water resource development and management must be pro actively addressed.
- A number of other issues of importance like adequate funds, legislation, research and people’s involvement at all important stages, etc are very important to effectively manage floods. However, the inter-state issues in multi state river basins is a very important matter waiting to be effectively addressed.
National Water Policy ( 1987/ 2002/2012)
The Government of India while framing policy has laid significant emphasis on the management of floods which gets reflected in the National Water Policy as under :
The National Water Policy (1987) adopted by the National Water Resources council, inter alia, recommended that “adequate flood cushion should be provided in water storage projects wherever feasible to facilitate better flood management”. While it recognized that “physical flood protection works like embankments and dykes will continue to be necessary”, it laid emphasis on adoption of non -structural measures for the minimization of losses, such as flood forecasting and warning and flood plain zoning etc.
The National Water Policy of 2002 adopted by the National Water Resources Council inter alia recommended the following guiding principles:
(i) There should be a master plan for flood control and management for each flood prone basin.
(ii) Adequate flood cushion should be provided in water storage projects, wherever feasible, to facilitate better flood management. In highly flood prone areas, flood control should be given overriding consideration in reservoir regulations policy even at the cost of sacrificing some irrigation or power benefits.
(iii) While physical flood protection works like embankments and dykes will continue to be necessary, increased emphasis should be laid on non-structural measures such as flood forecasting and warning, flood plain zoning and flood proofing for the minimization of losses and to reduce the recurring expenditure on flood relief.
(iv) There should be strict regulation of settlements and economic activity in the flood plain zones along with flood proofing, to minimize the loss of life and property on account of floods.
(v) The flood forecasting activities should be modernized, value added and extended to other uncovered areas. Inflow forecasting to reservoirs should be instituted for their effective regulation.
(vi) The erosion of land, whether by the sea in coastal areas or by river waters inland, should be minimized by suitable cost-effective measures. The States and Union Territories should also undertake all requisite steps to ensure that indiscriminate occupation and exploitation of coastal strips of land are discouraged and that the location of economic activities in areas adjacent to the sea is regulated.
(vii) Each coastal State should prepare a comprehensive coastal land management plan, keeping in view the environmental and ecological impacts, and regulate the developmental activities accordingly.
The National Water Policy of 2012 adopted by the National Water Resources Council inter alia recommended the following guiding principles:
General Flood Management Measures practiced in India
Different measures have been adopted to reduce the flood losses and protect the flood plains. Depending upon the nature work, Flood protection and flood management measures may be broadly classified as under:
(a) Engineering / Structural Measures
(b) Administrative / Non-Structural Measures
Engineering /Structural Measures
The engineering measures for flood control which bring relief to the flood prone areas by reducing flood flows and thereby the flood levels are –
(a) an artificially created reservoir behind a dam across a river
(b) a natural depression suitably improved and regulated, if necessary or
(c) by diversion of a part of the peak flow to another river or basin, where such diversion would not cause appreciable damage.
(d) by constructing a parallel channel bye passing a particular town/reach of the river prone to flooding.
The engineering methods of flood protection, which do not reduce the flood flow but reduce spilling, are:
(a) embankments which artificially raise the effective river bank and thereby prevent spilling and
(b) channel and drainage improvement works, which artificially reduce the flood water level so as to keep the same, confined within the river banks and thus prevent spilling.
Different aspects of some of the important measures for flood management are enumerated below:
Reservoirs can moderate the intensity and timing of the incoming flood. They store the water during periods of high discharges in the river and release it after the critical high flow condition is over, so as to be ready to receive the next wave. Their effectiveness in moderating floods would depend on the reservoir capacity available at that time for absorbing the flood runoff and their proximity to the likely damage centre. They are operated with a carefully planned regulation schedule which takes into account both the safety of the dam and related structures and the safe carrying capacity of the lower reaches of the river in their present condition.
Reservoirs are more effective for flood management if, apart from the incidental moderation available for any type of storage on a river, specific flood space is earmarked, as in the case of DVCDamodar Valley Corporation dams across the Damodar and its tributaries. The operation schedule or rule curve being followed should be reviewed and a suitable operation schedule/rule curve prescribed for the monsoon filling to ensure space for flood moderation but which can be filled for conservation at a later stage when high flows end.
In order to improve the efficiency of the reservoirs and improve the operation schedules for providing either incidental or specific flood moderation effects, arrangement for inflow forecasts should be made. 10.1.2 Detention Basins Detention basins are usually formed by utilizing natural depressions/ swamps and lakes by improving their capacity by constructing encircling embankments and providing suitable devices for regulating the release of stored waters. Since, the land under the marshes or low depression may hardly require much compensation and rehabilitation measures, this method are relatively in expensive. The Ghaggar detention basin in Rajasthan is a good example. Depressions available upstream of Srinagar City, on the left bank of river Jhelum, the Mokama Tal area in Bihar and Ottu, Bhindawas, Kotla lakes in Haryana and various beels/haors of Barak basin are some examples of a few natural basins.
Embankments (including ring bunds and town protection works) confine the flood flows and prevent spilling, thereby reducing the damage. These are generally cheap, quick and most popular method of flood protection and have been constructed extensively in the past. These are reported to have given considerable protection at comparatively low costs, particularly in the lower reaches of large rivers. In many places, embankments may be the only feasible method of preventing inundation. Embankments are designed and constructed to afford a degree of protection against floods of a certain frequency and intensity or against the maximum recorded floods till the time of their planning only (in the absence of detailed hydrological data for longer periods) depending upon the location protected and their economic justification. The raising and strengthening of existing embankments have also been taken up in many of the flood prone States. In order that this work is done adequately it is necessary to adopt the flood frequency approach in their redesign, taking into account the data of historical floods, which is now available.
Apart from the raising and strengthening works, erosion along the embankments and natural banks of the river systems has been a serious problem on which considerable expenditure has been incurred in the past. Particular mention could be made of the erosion problem of the embankment systems in Assam, Bihar, U.P, Punjab and West Bengal. The embankments, under serious attack by the major rivers and their tributaries, have to be suitably protected by spurs, pitching and other suitable anti-erosion measures. On many embankment systems like the Kosi embankment and Piprasi-Pipraghat embankment on the Gandak in Bihar, the river attack is so severe that the protection measures required to be taken are large and cannot be covered under the normal maintenance works.
A number of Committees constituted in various countries as well as in India have deliberated upon the utility of embankments as a means for flood protection. Divergent views have emerged out of these. Many NGOs have voiced serious criticism about existing embankments. One is that problems of flood can be solved by removal of all the existing embankments and the other diametrically opposite being that construction of more and more lengths of the embankments and their raising and strengthening is the only practicable medium/short term solution for the flood problems. The reason for such wide divergence in opinion is obviously due to the inadequacy of sufficient number of performance evaluation studies of existing embankments and the divergent views on their performance. As experienced, some embankments have provided positive benefits by ensuring sustained protection against floods and river spills while on the other hand, some embankments have, in certain reaches of the river, aggravated the flood problem by rising river bed levels, decreasing their carrying capacity, causing drainage congestion in the countryside and distorting the levels/gradient of the outfall points.
Construction of embankment with proper roads has been perceived as providing useful communication linkages and reliable surface network for areas that are liable to stand completely cut off during floods and thereafter. They could provide quick communication for facilitating better supervision and maintenance of the flood protection works and provide all weather communication facilities to the adjoining habitats. As such, they are often deemed as the life line during floods.
It is also recognised that embankments are not an unmixed blessing. They have adverse effects such as interference with drainage, inability to stand erosion, etc. which should be considered before planning this measure for flood management.
As such, this method of flood management may be undertaken only after carrying out detailed hydrological and other studies regarding their favourable and adverse effects.
Channelisation of Rivers
Some of the states are proposing channelisation of rivers, at least in certain reaches, in the context of tackling the extensive meandering problems of the rivers, activating navigational channels and training these rivers into their original courses. While venturing to channelise rivers, thought must be given in allowing the river certain freedom to flow and right of way to pass its flood waters and silt load within its natural waterway. The dynamic nature of the rivers should be appreciated and preventive measures planned accordingly instead of pinning down the river by channelising.
The method of improving the channel by improving the hydraulic conditions of the river channels by desilting, dredging, lining etc., to enable the river to carry its discharges at lower levels or within its banks has been often advocated but adopted on a very limited extent because of its high cost and other problems.
Dredging operations of the Brahmaputra, which were undertaken in the early seventies on an experimental basis, were discontinued because of their prohibitive cost and limited benefits. Dredging in selected locations may perhaps be considered as a component of a package of measures for channel improvement to check the river bank erosion subject to techno-economic justification. It may be economically justifiable as a method for channel improvement where navigation is involved. Dredging is sometimes advocated for clearing river mouth or narrow constrictions.
Surface water drainage congestion due to inadequacy of natural or artificial drainage channels to carry the storm water discharge within a reasonable period causes damages. It is often difficult to distinguish between flood and drainage congestion situations. This problem is rather acute in Andhra Pradesh, Bihar, Haryana, Punjab, Orissa, Uttar Pradesh, Assam and West Bengal, J&K, Gujarat and Tamilnadu. Therefore, improvement of drainage by construction of new channels or improvement in the discharge capacity of the existing drainage system is recommended as an integral part of the flood management programme in the country.
Stress has to be laid on improving the existing natural drainage system in the flood plains so that what should essentially be flooding of a few days should not get prolonged for months. In this context, the importance of the system ‘dhars’ or ‘old channels’, which efficiently served the function of draining away the spillage and surface flows generated by local rains, must be recognised. The blocking of these natural drainage channels, which is normally done in the name of “reclamation for development” because of paucity of land or vested interest, must be firmly discouraged. This applies also to all natural depressions, which are targeted for reclamation.
The adequacy of existing sluices and drainage channels should be reviewed in areas suffering from drainage congestion. If the capacities of existing sluices in embankments and drainage channels are inadequate, this should be improved by increasing the vents and improving outfall conditions.
Diversion of Flood Waters
Diversion of flood waters takes a part of the flood discharge to another basin or to the same basin downstream of the problem area or to a depression where it could be stored for subsequent release. This measure can be used to manage unusual floods around cities as in the case of flood spill channel near Srinagar and also in the lower reaches of a river near the sea as in the case of Krishna Godavari drainage scheme. Important schemes under execution or under planning are the supplementary drain in Delhi, the outfall channel in Jammu and Kashmir, the Damodar in the lower reaches in West Bengal, the Thottapally Spillway diversion in Kerala, the Kolleru lake diversion into the sea in Andhra Pradesh, the Kama-Pahari drain in Rajasthan and the Hulwaa drain in Uttar Pradesh.
The watershed management measures include developing and conserving the vegetative and soil covers and also to undertake structural works like check-dams, detention basins, diversion channels, etc. In the watershed management of upper catchment, land treatment through afforestation and grass land development practices should be supplemented by structural works for retarding the water velocity and arresting silt.
Administrative / Non-structural Measures
The administrative methods endeavour to mitigate the flood damages by;
(a) Facilitating timely evacuation of the people and shifting of their movable property to safer grounds by having advance warning of incoming flood i.e. flood forecasting, flood warning in case of threatened inundation
(b) Discouraging creation of valuable assets/settlement of the people in the areas subject to frequent flooding i.e. enforcing flood plain zoning regulation.
Providing absolute protection to all flood prone areas against all magnitude of floods is neither practically possible nor economically viable. Such an attempt would involve stupendously high cost for construction and for maintenance. Hence a pragmatic approach in flood management is to provide a reasonable degree of protection against flood damages at economic cost through a combination of structural and non-structural measures.
Flood Plain Zoning
Flood-plain zoning is a concept central to flood plain management. This concept recognises the basic fact that the flood plain of a river is essentially its domain and any intrusion into or developmental activity therein must recognise the river’s ‘right of way’. Flood-plain zoning measures aim at demarcating zones or areas likely to be affected by floods of different magnitudes or frequencies and probability levels, and specify the types of permissible developments in these zones, so that whenever floods actually occur, the damage can be minimised, if not avoided. Unfortunately, while all generally endorse this approach in principle, scant attention is given to it in actual practice, leading to increased flood damages.The Central Water Commission (CWC) has been continuously impressing upon the states the need to take follow-up action to implement the flood plain zoning approach. A model draft bill for flood plain zoning legislation was also circulated by the union government in 1975 to all the states.
There has been passive resistance on the part of the states to follow up the various aspects of flood plain management including possible legislation.
Flood proofing measures adopted in India in the past, consisted in raising a few villages above pre-determined flood levels and connecting them to nearby roads or high lands. Under this programme, several thousand villages were raised in Uttar Pradesh in the fifties. In West Bengal and Assam also land-fills were attempted in villages to keep houses above flood levels even though nearby agricultural lands were liable to inundation. During X Plan, the Government of Bihar had also constructed, with Central assistance, the raised platforms for safety of the people in flood prone areas of North Bihar.
The work of flood forecasting and warning in India is entrusted with the Central Water Commission (CWC). Flood Forecasting and flood warning in India was commenced in a small way in the year 1958 with the establishment of a unit in the Central Water Commission (CWC), New Delhi, for flood forecasting for the river Yamuna at Delhi. Presently, there are 878 Hydrological and Hydro-meteorological sites being operated by CWC across the country covering 20 river basins for gauge, discharge, sediment & water quality observations. The formulation of a forecast requires effective means of real time data communication network from the forecasting stations and the base stations (380 nos approx at present). Wireless Communication system installed in almost 550 stations is the backbone of the communication system required for flood forecasting activities. The activity of flood forecasting comprises of Level Forecasting and Inflow Forecasting. The level forecasts help the user agencies to decide mitigating measures like evacuation of people and shifting people and their movable property to safer locations. The Inflow Forecasting is used by various dam authorities in optimum operation of reservoirs for safe passage of flood downstream as well as to ensure adequate storage in the reservoirs for meeting demand during non-monsoon period.
Presently, Flood forecasts are issued by CWC at 175 stations (28 Inflow Forecast Stations and 147 Level Forecast Stations). Annually, about 6000 flood forecasts are issued by CWC during floods.
In order to meet the requirement of real-time data collection, automatic data transmission and flood forecast formulation, expeditious data / information dissemination, the Central Water Commission has undertaken modernization of its data collection and flood forecast network. During IX Plan, 55 telemetry stations were installed in Mahanadi and Chambal Basins besides setting up of two Earth receiving Stations ( ERS) at Jaipur ( Rajasthan) and Burla ( Orissa). During X Plan, modernization of 168 stations was undertaken; out of which 166 stations besides 11 Modelling Centres have been set up till date. During XI Plan, additional 222 stations and 10 Modelling Centres are proposed to be installed; which would help the concerned States in taking appropriate measures in advance for evacuation of people and shifting them and their properties to safer locations.