Flood Disaster Management

Abstract

Over the past several years, the intensity and frequencies of both riverine and urban flooding are showing increasing trends. In many of the Asian countries including India, flooding due to inundation in low lying areas along river channels as well as localized unprecedented precipitation has become a common feature that has gained the status of disasters causing devastations in terms of loss of lives and huge economic losses every year. The number of people affected by riverine and urban floods is more than any other type of natural disasters. The J&K Floods in 2014, Uttarakhand Floods in 2013 and the mega flood of Chennai (Tamil Nadu) in December 2015 highlight the vulnerability status of India.

The prime reasons of flooding being the reduced carrying capacity of river channels, unusual amount and intensity of rainfall in a localized area, climate change over the past decades, poorly managed land use planning, faulty drainage design, construction & management, lack of real time warning etc. Sometimes, sudden release of water from dams along with other localized phenomena also creates flooding. The increasing ramifications of such disasters have afflicted policy planners, scientists, researchers, academicians and others concerned across the world to find out ways and means to deal with the emerging threats of this typical hydro-meteorological phenomena.

The present chapter discuss in details about the fundamental concept of the management of disasters due to floods. The flood vulnerability status in SAARC countries is also discussed along with the existing vulnerabilities of Indian states. In addition the flood management and mitigation strategies are also suggested along with do’s and don’ts.

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1 Introduction

Flood is a unique hydrometeorological phenomenon having widespread occurrence across the globe with varied severity and dimensions. The World Disaster Report 2014 highlights the impacts of flood with another high-profile disaster like earthquake and declares that flood incidences in the world are nearly eight times more than that of earthquakes and the number of people affected by floods is nearly 12 times more.

There are different perceptions of flood for different stakeholders. For common people, it means devastation, destructions, damage, starvation, loss of lives, damage to properties and infrastructures, etc. Those living in urban areas may treat this phenomenon as disruption in their normal functioning of society. The government machinery and policy planners treat this situation as a factor of retardation in developmental planning with additional overburden on economy and additional expenditure on rescue, relief, rehabilitation, mitigation, etc. The engineering community, especially civil engineers, considers this as a situation review of existing flood protection measures.

In some of the South Asian countries including India, there is a typical condition of flood and drought occurrence at the same time. It is therefore essential to analyze the dynamics of floods and associated phenomenon so that appropriate flood management strategies and techniques can be adopted.

The International Commission on Irrigation and Drainage (1995) has defined “flood” as “relatively high flow in a river markedly higher than the usual”. The World Meteorological Organization (WMO)/UNESCO International Glossary of Hydrology (WMO 1974) defined flood as “rise, usually brief in the water level of a stream or water body to a peak from which the water level recedes at a slower rate” and “relatively high flows as measured by stage height or discharge.”

1.1 Types of Floods

Floods have been classified in various ways depending upon the nature, severity, and sources of inundation:

• Riverine flooding is the main flooding type that occurs due to various reasons but primarily due to heavy precipitation or glacial melt with resultant runoff. The increased discharge in river channels with decreasing carrying capacities leads to overflow causing inundation in the adjoining low-lying areas.

• Flash flooding is an unprecedented situation that occurs in hilly regions and sloping lands where torrential heavy precipitation, thunderstorm, or cloud burst commonly occurred without any prior warning. This sometimes cause huge loss of lives and damage to properties.

• Urban flooding occurs in regions where developmental planning has not been in tune with the geomorphological, ecological, and environmental set up, which results in the increased vulnerability in urban regions. Many urban agglomerations in India are suffering from the problem of flooding even after moderate rainfall. The situation aggravates when rainwater mix up with drain water causing many additional problems including spread of epidemics.

• Coastal flooding occurs due to a number of reasons like cyclones and associated storm surge, high tides, tsunami, etc., wherein the low-lying areas in coastal tracts are inundated, as a result of which losses occur on a larger scale. In addition, salinity increases in the coastal groundwater and wells.

• Glacial Lake Outburst Flood (GLOF) occurs in the downstream of glacial regions, where glaciers holding large quantities of water suddenly release them due to melting of ice jam. Glacial outburst is one of the prime reasons of flash floods in some of the Himalayan rivers.

• Cloud Burst Flood is the manifestation of climate change and hydrological imbalance that primarily occurs as sudden heavy rainfall. Cyclonic circulations in monsoon may also lead to cloud burst.

• Cyclone and storm surge flooding mainly occurs in coastal areas due to rainstorms associated with low-pressure systems. Movement of cyclonic storms in quick succession leads to severe flooding, especially in low-lying coastal areas.

2 Flood Vulnerability in SAARC Countries

The menace of flood in some of the SAARC countries like Bangladesh, India, Sri Lanka, and Pakistan is a recurrent phenomenon that directly affects their populace and economy and indirectly affects neighboring countries having trade relations with them. Despite adoption of several structural and nonstructural measures, flood causes huge loss of lives, damage to properties and infrastructures, and loss of economy and livelihoods. Every year about thousands of people lose their lives due to this annual hydrometeorological phenomenon with millions get homeless.

Even though several measures are being adopted in almost all the affecting nations to minimize the impact of floods, it’s still a matter of concern that damages due to floods are showing an increasing trend. The impacts are so severe that during the entire period of flood, the only companions with graved communities are despair, hope, anger, stress, and agony besides their disrupted life activities.

The worst repercussion of this phenomenon is damages to infrastructures like bridges, residential buildings, road networks, electricity transmission networks, telecommunication lines, etc. For the agricultural sector, it comes as an anathema causing huge damage to standing crops, vegetation, and overall agricultural productivity.

The flood also create disasters within a disaster, when the outbreak of epidemics and other waterborne diseases sets in affecting communities, which are already crippled in a disastrous situation.

It’s a matter of great concern that floods are now affecting areas in the entire South Asian regions which were otherwise considered flood-safe zone. This is showing an alarming trend in countries like India, Bangladesh, Pakistan, and Sri Lanka. The Climatologists, Hydro-geomorphologists, and other domain experts are citing this phenomenon as possibly arising due to the impact of global warming and climate change. Besides, the vast expansion of industrial and urban agglomerations and increasing developmental activities are also causing threats to the situation (Table 20.1).

Table 20.1 Decadal flood damages and deaths in South Asia (2005–2015)

The entire South Asian countries except Maldives and Sri Lanka receive most of the precipitation from the southwestern monsoon which, in general, prevails from June to September and contributes about 70–80 % of rainfall in the region. On the other hand countries like Maldives and Sri Lanka receive mostly North Eastern Monsoon. Occasionally, climatic phenomenon like western disturbance also causes rainfall in some parts of Sri Lanka, India, Pakistan, etc.

2.1 Afghanistan

Flood is the most common hydrometeorological disaster in Afghanistan, mainly affecting foothill regions of mountains and alluvial plains of rivers in the northern provinces. The main river of Afghanistan is Amu Daria, which is connected with branches having their sources lying in the mountains. During spring and early summer, these rivers are fed by snow melts, which increase discharge volume in rivers, causing floods in low-lying areas. The heavy rainfall or avalanches in the region also sometimes cause flood, especially flash floods, e.g., flash floods in Faryab and Baghlan province on May 8, 2015. The Avalanche-induced floods occurred in provinces like Panjshir, Nangarhar, Laghman, Kapisa, Parwan, Nuristan, and the capital Kabul in February 25–27, 2015; flash floods in Jawzjan province and Badakhshan province in April to June 2014; etc. (SAARC Disaster Knowledge Network Portal) (Table 20.2).

Table 20.2 Decadal flood damages and deaths in Afghanistan (2005–2015)

Floods in Afganistan

2.2 Bangladesh

Geographically, the People’s Republic of Bangladesh is located at the confluence of Padma (Ganges), Jamuna (Brahmaputra), and Meghna rivers and their tributaries. On account of being located in the downstream of these three rivers, the country is extremely vulnerable to flooding. Some of the historic floods in the years 1987, 1988 and 1998 had created great disasters in the country, leaving behind the trials of devastations and destructions. In addition, floods have also been affecting the country due to localized reasons like collapse of embankments and tidal effects in the coastal regions.

There are two types of flood occuring in Bangladesh – annual (moderate) flood known as barsha, which does not cause significant damage of communities, whereas high-intensity flood Banna creates destruction and devastation, inundating about 35 % of the areas. Some of the recent examples of flood are that due to heavy rainfall in the southeastern district of Cox’s Bazar and neighboring Bandarban in June 2015 and flooding due to collapse of embankments of river Kholpetua in southwest district of Satkhira in March 2015, which caused substantial losses in the country (Table 20.3).

Table 20.3 Decadal flood damages and deaths in Bangladesh (2005–2015)

2.3 Bhutan

On account of unique geological and geographical location, Bhutan is not much prone to annual floods. The country is located in the high mountainous regions with deep, narrow gorges through which rivers flow in a confined channel. This unique topographic characteristic has made the country less vulnerable to annual floods except occassional flash floods somewhere in the lower reaches due to heavy precipitation. This sometimes carries boulders, pebbles, and cobbles along with a high flow of waters which causes substantial loss of lives and damage to properties and infrastructures of downstream cities and communities. In May 2009 heavy precipitation due to the impact of cyclone Aila exceeded the water bearing capacity of rivers Punakha and Wangdue affecting almost all the districts.

There are other threats of flood in Bhutan known as Glacial Lake Outburst Floods (GLOF). Due to the impact of climate change and other localized hydrometeorological factors, the Himalayan glaciers are shrinking rapidly. The retreating glaciers increase the volumes of water in the existing lakes created by glacial erosion, as a result of which lakes burst with consequent flooding occurs in the foothill regions. As per the study conducted by the Department of Geology and Mines, Bhutan, in collaboration with ICIMOD, there are 2674 glacial lakes existing in Bhutan, out of which about 562 are associated with glaciers. Twenty-five of them are considered as potentially dangerous lakes that could pose a GLOF threat in the near future (SADKN Portal).

2.4 Nepal

The mountainous country of Nepal is considered among the most vulnerable flood regions in South Asia. The rivers like Narayani, Kosi, Karnali, Mahakali, etc., are perennial in nature. They are fed by waters coming from snow clad mountains. During monsoon period, all the rivers receive excess water in addition to glacial melts. This causes flooding especially in Terai regions of Nepal. Some of the devastating floods occurred in 1978 (Tinao basin), 1980 (Tadi basin), 1987 (Sun Koshi basin), and in August 2008, Kosi floods, that caused devastation in eastern Nepal affecting about 200,000 people. One recent flood also occurred in Taplejung district in June 2015 (Table 20.4).

Table 20.4 Decadal flood damages and deaths in Nepal (2005–2015)

2.5 Maldives

The group of 142 inhabited islands (source- SADKN) is particularly vulnerable to localized floods of lesser severity. These include rainfall-induced flooding, tidal flooding in low-lying coastal areas due to high tides, flooding due to storm surge during cyclones, etc. The long-term perspective also predicts climate change with the resultant sea level rise as a potential threat of flooding especially in low-lying coastal areas.

Some of the remarkable flooding in Maldives occurred in 1987 and 2007 affecting more than 2000 people in the country (source-The International Disaster Database) (Table 20.5).

Table 20.5 Flood damage in Maldives (2005–2015)

2.6 Pakistan

Pakistan is among those South Asian countries, where flood is considered a major annual hydrometeorological phenomenon. There are several types of flood occurring due to spatial and temporal variations across the country causing disasters. The most common among them are riverine flood due to the monsoonal impact, mostly from July to September. Due to this impact, the majority of the river basins, especially Punjab and Sind provinces, are inundated causing severe floods. The snow melt in the upper reaches aggravates the situation. Flash flood also occurs in northern provinces of Pakistan, which causes great devastations in the region. During monsoon, cities like Islamabad, Lahore, Peshawar, Karachi, etc., are severely exposed to urban flooding. In addition, provinces like Sindh and Balochistan are particularly affected by coastal flooding due to cyclonic impact and resultant storm surge. The Makran coastal regions have gained notoriety of having frequently exposed to coastal flooding.

For the last 114 years, flood hazards have claimed about 12,156 lives with a total affected population of about 5.70 crores in the region. Flood alone has caused total damages of more than 19 billion dollars. Some of the remarkable floods in recent past includes flash flood in the Pakhtunkhwa province in northwest Pakistan (June, 2015), Balochistan province due to heavy torrential rainfall (June, 2015) (SAARC Workshop Report 2012) (Table 20.6).

Table 20.6 Decadal flood damages and deaths in Pakistan (2005–2015)

2.7 Sri Lanka

Flood in Sri Lanka is a commonly occurring phenomenon, causing destructions and devastations more than other disasters in the country. Physiographically, northeastern and southwestern parts are particularly vulnerable to floods. Flooding is mostly triggered by both the branches of monsoonal precipitation – southwest and northeast monsoon. The former strikes and inundates districts like Kegalle, Ratnapura, Kalutara, Colombo, Gampaha, and Galle, whereas the latter causes extensive flooding in districts like Ampara, Trincomalee, etc. (Table 20.7)

Table 20.7 Decadal flood damages and deaths in Sri Lanka (2005–2015)

3 Flood Vulnerability in India

In the entire Indian subcontinent, the flood gains the status of disaster, when normal channels of rivers are breached or flow in excess of their carrying capacity. Flood is a recurrent phenomenon in India that normally starts with the onset of monsoon; however, due to localized hydrometeorological aberrations, there has been specific flooding in localized areas. The United Nations International Strategy for Disaster Reduction (UNISDR) Report 2015 observed that out of the average annual loss of 9.8 billion USD in India, about 7.4 billion USD are accounted by the damage caused by floods.

Rashtriya Barh Ayog (RBA) constituted in India to assess the flood situation in the country has listed the flowing situations for flooding:

• Streams flowing in excess of the transporting capacity

• Backing up of water in tributaries

• Heavy rainfall

• Ice jams or landslides blocking stream courses

• Heavy localized rainfall

• Cyclones and typhoons

Out of the total geographical area of 329 million hectares, about 40 million hectares is liable to floods in India as estimated by the RBA in 1980. Subsequently 11th five-year plan working group has compiled the area liable to flood as 45.64 million hectare. It is estimated that about 25 out of 36 states and union territories are flood prone in the country. The areas stretching north to south from the extrapeninsular regions to the tip of the peninsula and from extreme desert regions of the west to the east coastal regions and northeastern regions are all prone to floods in varying magnitude and nature.

The following table shows annual and decadal damage status in India due to floods (Table 20.8).

Table 20.8 A damage due to floods/heavy rains during 2000–2012 in India

There are about 22 major river basins in India, out of which four major river basins are typically known as flood-prone basins:

• 1. Brahmaputra and Barak basin

• 2. Ganga basin

• 3. North West River basins

• 4. Central India and Deccan river basins

The Brahmaputra basin covering northeastern states, northern part of West Bengal, and Sikkim is affected by severe and recurrent floods. The entire catchment area of this basin receives heavy rainfall from June to September. The frequently occurring earthquakes and landslides in hills upset the flow regime of rivers causing imbalance in flow dynamics. In addition, spilling of rivers, drainage congestion and tendency of some of the rivers to change courses also cause flooding. In Assam and Tripura, flooding primarily occurs due to inundation by spilling of Brahmaputra and tributaries as well as bank erosion along the Brahmaputra.

In the Ganga Basin, flood problems are mostly confined to the northern bank of the Ganga. This recurrent phenomena occurs mostly due to spilling over banks and change in river courses; however, erosion problems are confined to a few places. The problem increases from west to east and from south to north.

In North West River basin, covering Punjab and Haryana, inadequate surface drainage along with high rainfall causes flooding and waterlogging over vast areas.

The Central India and the Deccan basin covers all southern states where most of the rivers have well-defined and stable courses, but inadequate capacity in lower reaches and delta regions causes flooding. In addition, urban flooding also occurs due to heavy rainfall. The deltas of Mahanadi, Godavari, and Krishna periodically face flooding in the wake of cyclonic storm.

The varied climatic and rainfall patterns in different parts of the country create typical situation in a way that while some of the regions are suffering from floods due to excess of waters, at the same time, other regions might be affected due to drought conditions (Table 20.9).

Table 20.9 Areas liable to floods in India

The above table indicates the widespread occurrence of flood across the country, but states like Uttar Pradesh, Assam, Bihar, West Bengal, Odisha, etc., are typically more vulnerable to perennial flooding. The brief account of flood vulnerability in some states are discussed below.

3.1 Assam

The Rashtriya Barh Ayog (RBA) has declared the state of Assam as the most flood-vulnerable state in the country. Out of the total geographical area of 7.84 million hectares, about 3.15 million hectare land (40.18 %) is prone to floods. This makes 9.4 % of the total flood-prone areas of India (source-ASDMA). In addition to annual flooding, the state is also affected by flash floods during monsoon (Flood hazard Atlas of Assam).

Assam is situated in the middle of the two major river basins – Brahmaputra and Barak. Due to typical geo-climatic condition, there are high risks of floods in these basins. Besides, there are a number of natural and anthropogenic reasons of flood occurrences in the state. The heavy monsoonal precipitation combined with a unique physiographic setup makes the region highly susceptible to flood hazards. The situation gets aggravated when the narrow valley of the Brahmaputra compounded with steep gradient of channels create the situation of drainage congestion and consequent flooding (Table 20.10).

Table 20.10 Vulnerability status of Assam

3.2 Uttar Pradesh

Flood is a commonly occurring disaster in Uttar Pradesh that is also a recurrent phenomenon every year. Due to typical hydrometeorological and geomorphological conditions, eastern, central, and Terai regions of the state are more vulnerable to flood.

As per RBA estimation, 73.36 lakh hectares of the total geographical area are prone to flood, that are mostly concentrated in eastern Uttar Pradesh. Out of the total 76 districts in the state, 34 are flood prone (Table 20.11).

Table 20.11 Vulnerability status of Uttar Pradesh

There are about eight prime rivers crossing the state that create devastations, when they are in full spate- Ganges, Yamuna, Ramganga, Gomati, Sharda, Ghaghara, Rapti, and Gandak. The annual precipitation due to southwest monsoon is the main flood-inducing factor in the region. About 80 % of the total rainfall (60–190 cm) received by the state is in the form of SW monsoonal precipitation. The pattern of flood occurrence follows the pattern of precipitation that increases from west to east and from south to north. As per the rough estimate, the average annual loss to crops, houses, and livestock in the state is to the tune of about INR 2000 crores {source-UP Govt. Report}.

3.3 Bihar

The state of Bihar is known as the theater of natural disasters especially flood on account of its recurrent nature every year with resultant loss of lives and substantial damages. As per the estimation done by the Water Resources Department, Govt. of Bihar, about 56 % of the total geographical area of the state is affected by flood and permanent waterlogging (Taal).

Bihar is geographically divided by river Ganges into two main regions – North Bihar and South Bihar. The former is fed by rivers flowing from the Himalayas and covering the entire North Bihar. Rivers like Ghaghra, Gandak, Burhi Gandak, Bagmati, Kamla, Kosi, Mahananda, and Adhwara have their catchment extending from Nepal to Bihar. Mostly being of glacial origin, these rivers are perennial in nature, thus maintaining an optimal level of flow round the year. During monsoonal precipitation, these rivers get an additional volume of water leading to large-scale flooding situations in the entire stretch of North Bihar. As per the estimation, 73.63% area of North Bihar is considered as flood prone {5}.

The river Ganges on its left bank receives tributaries like Ghaghra, Gandak, Kosi, etc. Since they are mostly of Himalayan origin, they carry along with them a large amount of silts, which are deposited all along their channels in the Indo-Gangetic plains. Heavy siltation combined with anthropogenic obstructions lead to overtopping of excess river water, causing widespread inundation and consequent flooding in the catchment area. The situation gets aggravated by further inundation through rivulets existing in the interfluves of all these tributaries. Due to prolonged siltations, some of these rivers have acquired characteristics of changing their courses, thereby destructing habitations and agricultural cultivation in the adjoining locations. The river Kosi is one such river, which has gained the notoriety of changing course drastically. During the last two centuries, this river has moved nearly 110 km westward, devastating the entire area that came in her path. Being very destructive in nature, this river is termed as River of Sorrows.

The geographical and geological setup in the south of river Ganges (South Bihar) is somewhat different. The region having a total geographical area of 44,000 km² is drained by rivers like Karmanasa, Sone, Punpun, Kiul, Badua, Chandan, etc. They are mostly rain fed. During monsoon period, the surplus water in these rivers get accumulated along the southern tracts of the natural levee of river Ganges, causing flood. The wetland region, lying south of river Ganges known as Taals, are also inundated by these surplus waters.

There are 28 flood-prone districts in Bihar, out of which 15 are considered as the most vulnerable and 13 are less vulnerable (Table 20.12).

Table 20.12 Flood-vulnerable districts of Bihar

The historical Kosi flood in 2008 is considered as the worst disastrous flood ever occurred in the country. On August 18 2008, an unprecedented flood situation occurred when the river Kosi breached eastern afflux embankment near village Kusaha in Nepal. This led to the formation of new scattered channel east of the old channel releasing about 1.66 lakh cusecs of water spreading across the channel causing devastations mostly in districts like Saharsa, Madhepura, Purnia, Supaul, Forbesganj, Araria, Katihar, etc. Over 3.3 million people affected due to sudden onset of this disaster with over a million rendered homeless. The loss of about 3000 km² of fertile land was reported. About 412 g panchayats under five districts were severely affected due to this natural calamity. A total of 3,40,742 houses collapsed with more than a thousand animals died. All the basic amenities were severely disrupted in the affected districts. The railway tracks submerged, the electricity lines were disrupted, and many roads and communication networks were damaged in this catastrophe. The state government immediately started disaster response operations with the help of central government.

3.4 Punjab and Haryana

In the alluvial plain of Punjab and Haryana, the main reason of flooding is waterlogging and drainage congestion. In Punjab, the entire alluvial plains are basically old floodplains of rivers. The alluvial plains of Ravi Beas, Satluj, Ghaggar, and Markanda rivers along with other rivulets constitute about 10 % of the state geographical area. Rivers like Ghaggar and Markanda sometimes inundate the adjoining low-lying areas after their courses are choked and obstructed especially during the monsoon period.

The drainage system in parts of Jind, Rohtak, Hisar, and Gurgaon districts of Haryana are either poorly developed or damaged causing severe flooding (Table 20.13).

Table 20.13 Flood-prone districts of Punjab

The Punjab and Haryana plain together accounts for about 45 % of the total flood loss incurred by the country. There are various factors leading to higher degree of vulnerability to floods in both the states. In Punjab, almost 80 % of the total annual rainfall is concentrated over a short period of 3 months, which coincides with the cropping seasons. In addition, the increased developmental practices in the region have resulted to more encroachments in the floodplains, causing enhanced vulnerability of flood. The natural geomorphic structure of Haryana is like a saucer-shaped depression, along the linear axis of Delhi-Rohtak and Hisar-Sirsa. Due to heavy precipitation and poor drainage network, sometimes the entire area gets flooded, e.g., Rohtak flood (1995). In addition, some of the recently emerged urban agglomerations are facing the problems of drainage congestion and localised urban flooding due to inadequate or faulty drainage system.

3.5 Rajasthan

The state of Rajasthan is typically known as the drought-prone region of India with generally little or scanty rainfall. There are about 13 river basins and sub-basins in the state out of which basins of three rivers – Chambal, Banas, and Luni are particularly prone to flooding due to reasons like excess rainfall in the catchment areas, sudden release of water from dams, breach in the embankment, decreased water bearing capacity of dams, etc. Besides these, the change in rainfall pattern has also increased the risk of flash floods. In 2006, the Barmer flood occurred due to unprecedented heavy rainfall in the region. Districts like Barmer, Jalore, Sirohi, Pali, Chittorgarh, Kota, Bharatpur, Bundi, etc., are among the flood-prone districts in the state.

3.6 Odisha

On account of typical geomorphological and hydrometeorological setup combined with maritime impacts, the state of Odisha is vulnerable to flood in several ways. Primarily, flooding occurs due to heavy monsoonal precipitation, as about 80 % of the total annual rainfall is received over a short period of 3 months. Because of the heavy siltation in rivers like Mahanadi, Brahmani, and Baitarani. The surplus water overtops the main channels and inundate adjoining areas. Sometimes, embankments are also breached due to heavy pressure of flood water. Since these rivers have common delta, they create a disastrous situation, while in the high spate. The situation gets aggravated when flood synchronizes with the condition of high tide.

The linear coastal tract of Odisha is also vulnerable to storm surge, especially during cyclone season. This situation is often accompanied by heavy precipitation that resulted in flooding in the lower reaches of the coastal districts. The deforested catchment areas and offshore bars choke the river mouths and obstruct the free flow of waters into the sea. In 1960, the region was hard hit by unprecedented flood. In super cyclone of 1999, many of the low-lying coastal districts were completely inundated. The high population density along with poor socioeconomic condition has led to increased encroachment in the entire stretches of floodplain, which ultimately increased the vulnerability of floods in the state. Out of the total 30 districts, 24 are flood prone, including nine most vulnerable districts as depicted in Table 20.14. For the last 10 years, floods in the state have caused great havoc with resultant loss of lives, properties, and infrastructures. The most severe flood that occurred in 2006, 2007, 2008, and 2011 had caused huge devastation.

Table 20.14 Flood-prone districts of Odisha

Ganjam Flood, Odisha (Source-NDRF)

3.7 Gujarat

On account of the maritime impact and typical geomorphic setup, the state of Gujarat receives heavy precipitation, which often results in the inundation of low-lying areas and consequent flooding. In addition, there are other factors responsible for flooding in the state. In 1979, a flood in Morbi city occurred due to dam break in which about 12,000 people died. In August 2006 Surat city and South and Central Gujarat got affected by flood wherein about 250 people died of drowning and leptospirosis.

3.8 West Bengal

The state of West Bengal has the total geographical areas of 88.75 lakh hectares out of which about 37.6 lh of land is identified as flood prone spreading over 111 blocks. The state is typically vulnerable to three main types of flooding – flash floods, riverine floods, and coastal floods. The flash floods occur due to the impact of heavy torrential rainfall supplemented with cloud burst, storm surge, and cyclonic impact. In urban agglomerations, the condition gets aggravated due to poor and choked drainage system coupled with poor urban planning. Riverine flooding occurs when the surplus volume of water due to high precipitation added in the river channels, particularly when they are in full spate. Most of the rivers flowing in the state are having their origin in Nepal, Bhutan, and Sikkim (India), and they flow downstream to meet either in the sea or neighboring country of Bangladesh before meeting to the ultimate destination. The rivers like Teesta, Torsa, Jaldhaka, Raidak (I&II) flows through the districts of Jalpaiguri and Cooch Behar. They cause intense flooding in these districts when there is high precipitation in the upper reaches.

The river Mahananda when gets high discharge in the upper catchment area, causes flooding in Uttar and Dakshin Dinajpur. The district of Malda is flooded due to high discharge of rivers Fulhar-Mahananda-Ganga. The river basins of Bhagirathi-Hooghly create flooding primarily due to excessive discharge in these rivers on account of high precipitation in the catchment area associated with drainage congestion and decreased carrying capacity of river channels. The most affected regions are from Jangipur (Murshidabad) to Kalna (Bardwan). The South Bengal in general is flood prone having threats of riverine flooding and tidal flooding. The situation acquires an alarming position when tidal bore is also at peak during flooding in rivers. The districts like Darjeeling (N Bengal), Bankura, and Purulia (S Bengal) are comparatively free from flood threats. Out of the total 20 districts in the state, 15 are considered as flood prone (Table 20.15).

Table 20.15 Flood-vulnerable districts of West Bengal

3.9 Andhra Pradesh

Traditionally Andhra Pradesh is affected by multifaceted problems of flooding. While rivers like the Godavari and the Krishna along with other smaller rivers inundate surrounding areas due to excessive inflow in their channel beyond the carrying capacity, storm surge along the coastal belt also results in flooding. In addition, the drainage congestion mostly in delta regions is also responsible for flood problems in the state. In Telangana region (now a state), Khammam district is vulnerable to monsoonal flooding that occurs due to NE monsoon. The coastal belt from Nizampatnam to Machilipatnam is affected by storm surge flooding mostly due to cyclonic impact. The delta regions of Godavari and Krishna that are the most fertile regions of Andhra Pradesh experience problems of recurrent flood and drainage congestion.

Besides monsoonal and storm surge flooding, the riverine districts are also vulnerable to floods occuring due to peak discharges. The dams located along various rivers release excess water in the downstream when they are in high spate. To cite some examples, peak discharge of river Krishna at Vijaywada from NS Dam in the years 1989, 1990, 1991, 1998, and 2009 caused flood in the districts of Guntur, Krishna, Nalagonda, Kurnool, and Mahaboobnagar, and peak discharge of river Godavari at Perur affected districts of Khammam and East and West Godavari in the years 1986, 1990, 1992, 1994, 2004, 2005, and 2006. Peak discharge of river Penna at Nellore affected Nellore district in 1988, 1991, and 2001. Similarly, peak discharge at river Vamsadhara at Gotta barrage (I & CAD) badly affected Srikakulam in 1990 and 1992. Peak discharge at river Nagavalli also affected Srikakulam and Vijayanagaram in 1990, 1991, 1992, 1994, and 1996 (source-KSNDMC)

3.10 Flooding in Highland States

Flooding in the highlands or extrapeninsular regions of India is unique in terms of nature and magnitude considering the unique geomorphological topography. They are also known as upstream flooding that mostly occurred in the form of flash floods, cloud burst, or glacial lake outburst floods. They occur in a small, localized, and upper parts of the basin. The states mostly affected by this hydrometeorological phenomenon are Uttarakhand, Himachal Pradesh, J&K, Sikkim, etc.

3.10.1 Uttarakhand (Flood 2013)

On June 16 and 17, 2013, the state of Uttarakhand received more than 340 mm of rainfall, which was 375 % more than the normal benchmark of 65.9 mm rainfall during a normal monsoon. The sudden occurrence of cloud burst near Kedarnath temple and flooding in rivers like Bhagirathi, Mandakini, Ashiganga, Kali caused flash floods. This created one of the greatest disasters in the Indian history. Four out of 13 districts were heavily affected by floods, which created huge devastations in terms of loss of lives, properties, and infrastructures. At least 5000 people reported to have been killed in the deluge that inflicted heavy damage especially in the Kedarnath valley. Many thousands of pilgrims of “Char-Dham” Yatra were also affected. The unprecedented cloud burst and subsequent flash floods caused huge loss of lives and properties particularly in Rudraprayag, Pithoragarh, Uttarkashi, and Chamoli districts.

3.10.2 Jammu and Kashmir (Flood 2014)

The Jammu and Kashmir state has a very peculiar geography and climate. Most of the valley regions of the state are fed by rivers like Jhelum, Indus, and Chenab. The low lying areas of the Kashmir Valley, especially Srinagar, along with parts of Jammu, are prone to floods that occur due to heavy rainfall in upper catchment areas. Heavy rain followed by flash flood in September 2014 caused great devastation in the valley that claimed at least 280 lives and stranded hundreds of thousands of residents. The flood was unprecedented in nature, where the most part of the southern district has received very high rainfall. The weekly total rainfall for most of the stations during the period Sept 2 to Sept 8, 2014, was more than 200 mm. This is very high for a terrain like Jammu and Kashmir. The table below shows spatial distribution of weekly rainfall for select India Meteorological Department stations in J&K.

• Rainfall status during 2 weeks in August to Sept. 2014

  Actual (mm)	Normal (mm)	Departure (percent)	Category
  43.2	27.9		E

• August 28 to Sept. 3 2014

  Actual (mm)	Normal (mm)	Departure (percent)	Category
  267.7	30.0	792	E

• Sept.4 to Sept.10, 2014 (Source –IMD/Frontline)

The primary cause was incessant rainfall that occurred due to western disturbance on September 3rd 2014 and continued for 4 days. The melting of snow also added the severity of floods. The districts like Anantnag, Baramulla, Doda, Jammu, Kulgam, Pulwama, Ramban, Reasi, Sopian, and Udhampur received extremely heavy rainfall which inundated many low lying areas of the state. Huge devastation occurred in these districts in the form of loss of houses, livestock, crops, and livelihoods. Many cities were badly affected. The capital city Srinagar was marooned due to flood for many days. Many localities turned into lakes with collapsed houses and communication networks.

Geomorphologically, it is said that the huge devastation occurred due to the absence of floodplain along the river Jhelum which could have accommodated excess of runoff averting floods in the valley. The massive urbanization in the urban localities of J&K along river Jhelum led to the destruction of floodplains almost all along the river, which added the severity of floods in the valley.

After the disaster, the National Disaster Management Authority took control of the situation and started disaster response at different locations in the valley. National Disaster Response Force (NDRF) battalions pressed into action along with Indian Armed forces to provide rescue and relief. The armed forces (including Army, Navy, and Air Force) and National Disaster Response Force (NDRF) launched one of the biggest search and rescue operations in the state. Operation “Megh Rahat” and operation “Sahayata” involved all the three wings of armed forces and NDRF which rescued people from inundated areas and provided them food, water, medicines, and shelters. By September 19, 2014, over 2.37 people were rescued by the joint efforts of these forces. The army deployed about 30,000 troops for search, rescue and relief operations.

The following table gives an account of flood occurrence in India from 2005 to 2014 (Table 20.16).

Table 20.16 Flood occurrence in different states of India (2005–2014)

4 Flood Forecasting and Early Warning System

The forecasting and early warning is an integral and important component of flood risk management, which enables authorities and communities to take appropriate preparedness measures for impending flood situations in order to reduce flood damages and loss of lives.

Flood forecasting a non structural mitigation measures, which are considered complimentary to structural mitigation measures. There are primarily three types of forecasts prevalent in India and many South Asian countries – Stage forecast, Inundation forecast and Inflow forecast. While the stage forecast or level forecast gives information about water level in rivers, inundation forecast gives estimation about areas likely to be inundated or submerged during the high flood situation. The inflow forecast provides information about the amount of discharge in the river.

The flood forecasting system in India was established in the year 1958 in a scientific manner, when the Flood Forecasting Unit (FFU) was set up by the erstwhile Central Water and Power Commission (CW&PC) for generating and issuing flood warning at river Yamuna in Delhi. Since then, the system has been gradually expanded to other parts of the country with more advanced and scientific technology.

4.1 Stages of Flood Forecasting

There are four main stages of flood forecasting and warning in India

• 4.1.1 Real-time data collection

• 4.1.2 Transmission of data

• 4.1.3 Data processing and preparation of forecasts and warning

• 4.1.4 Dissemination of flood forecasts and warning

4.1.1 Real-Time Data Collection

The collection of real-time meteorological (rainfall) and hydrological (gauge discharge) data is the prime requisite for generating flood forecasts and warnings. While, at the central level, India Meteorological Department (IMD) and Central Water Commission (CWC) receive meteorological and hydrological data respectively through their base stations located across the country, a few states like Bihar, Karnataka, Andhra Pradesh, Tamil Nadu, etc., have established their own automatic weather stations generating and utilizing data for flood forecasting and early warning besides getting information from few national organizations.

IMD through its 10 flood meteorological offices receive daily rainfall data from more than 7000 centralized and state rain gauge stations in addition to forecasts of heavy rainfall and quantitative precipitation forecasts for various river basins. All these data are supplied to the respective flood forecasting centers of CWC.

4.1.2 Transmission of Data

The data generated at various hydrological and hydrometrological stations are transmitted to flood forecasting stations through different means of communication systems like VHF/HF wireless sets, telephones, V-Sat, Internet, etc.

There are 544 wireless stations owned by the Central Water Commission meant for near real-time data transmission. The high-frequency (HF) wireless sets are having 3–30 MHz frequency used for long-distance transmission of data, whereas very high-frequency (VHF) wireless sets with frequency range 30–3000 MHz are used for short-distance communication.

In addition, about 445 stations of CWC are equipped with (or somewhere under installation) satellite-based “telemetry stations” for generating automatic data communications (CWC Annual Report 2013).

During the Xth five-year plan, CWC established sensor-based telemetry stations at 223 locations across the country in basins of river Krishna, Godavari, Mahanadi, Chambal, Damodar, Yamuna, and R. Brahmaputra. Further, 222 telemetry stations were established during 11th five-year plan. It is proposed to establish another 600 stations during XII plan, which covers the entire country. All the sensors located at these stations will transmit data to earth stations located at Jaipur (Rajasthan) and Burla (Odisha) through INSAT or Kalpanasat satellites. All these received data are further transmitted through V-Sat to different modeling centers (CWC Annual Report 2013).

The transmission of data takes place twice to thrice in a day, depending upon flood situation. In case of extreme flooding, the transmission frequencies are even increased to hourly basis.

4.1.3 Data Processing and Preparation of Forecasts and Warnings

After receiving hydrological and hydrometeorological data from ground stations, the various modeling centers of CWC undertake data processing by using advanced software.

Primarily the precipitation and discharge data are utilized for forecast generation on a real-time basis. For example, inflow forecasts are generated by using rainfall runoff correlation through Windows-based hydrodynamic simulation modeling software MIKE-11. The Central Water Commission has developed a site-specific model for different locations under various divisions by using MIKE-11.

The flood forecast model for Srinagar (J&K) is currently under formulation based on MIKE-11. Similarly, the development of flood forecast models for rivers like Sankosh, Godavari, Brahmaputra, Jhelum, Alaknanda, and Yamuna basin has been taken up by the Central Water Commission (CWC).

4.1.4 Dissemination of Flood Forecasts and Warning

The final flood forecast information generated through various processes are disseminated to user agencies for issuing early warning and undertaking appropriate flood preparedness measures. The information is also circulated in print and electronic media for dissemination to local populace. Some of the user agencies like National Disaster Management Authority (NDMA), National Disaster Response Force (NDRF), state governments, railways and roadways authorities, defense forces, etc., are regular recipients of flood forecast information.

4.2 Agencies Involved in Flood Forecasting and Early Warning

4.2.1 Central Water Commission

The Central Water Commission is the technical agency dealing with water resources and flood management working under the Ministry of Water Resources, River Development and Ganga Rejuvenation, Government of India. The agency is entrusted with the general responsibilities of initiating, coordinating and furthering in consultation of the state government concerned, schemes for control, conservation and utilization of water resources throughout the country, for the purpose of flood control, irrigation, navigation, drinking water supply and water power development” (Central Water Commission, Ministry of Water Resources, River development & Ganga Rejuvenation, Govt. of India).

A separate River Management Wing has been established in CWC specifically for undertaking all activities related to flood management in the country. The wing is headed by Member (River Management) having an ex-officio status of Additional Secretary to the Govt. of India. There are various directorates in this wing headed by respective directors.

The role of this wing in the management of flood is primarily centered on collection, compilation, collation, and analysis of hydrological and hydrometeorological data and sharing of flood forecast analysis and early warning information to concerned state government and other user agencies except Ganga and Brahmaputra river basins for which two separate organizations have been created. The other functions of river management wing are as under:

• Formulation and dissemination of flood forecasts for all flood-prone rivers

• Providing support to state governments in technical matters of river and flood managements

• River morphology studies, appraisal of flood management schemes

• Provide advisory support to all user agencies including National Disaster Management Authority (NDMA)

The systematic approach of flood forecasting and early warning was initiated by CWC in 1969 with the establishment of flood forecasting and warning organization (Annual Report 2013). With the advancement of new technology, the flood forecasting network of CWC got strengthened. At present, there are 175 flood forecasting stations working under the National Flood Forecasting and Warning Network of CWC, out of which 28 stations are working for inflow forecasting and 147 are for level forecasting as listed in the table below.

River system-wise distribution of flood forecasting state
Sr. No.	River system	Types of forecasting station		Total
		Level forecasting	Inflow forecasting
1	Ganga system	77	10	87
2	Brahmaputra system	27	–	27
3	Barak system	5	–	5
4	East flowing river system	8	1	9
5	West flowing river system	9	6	15
6	Southern system	3	1	4
7	Mahanadi	14	4	18
8	Godavari	3	6	9
9	Krishna	1	–	1

1. CWC Report (2013)

State wise distribution of flood forecasting station
Sr. no.	River system	Types of forecasting station		Total
		Level forecasting	Inflow forecasting
1	Andhra Pradesh	9	7	16
2	Assam	24	–	24
3	Bihar	32	–	32
4	Chhattisgarh	1	–	1
5	Gujarat	6	5	11
6	Haryana	–	1	1
7	Jharkhand	1	4	5
8	Karnataka	1	3	4
9	Madhya Pradesh	2	1	3
10	Maharashtra	7	2	9
11	Odisha	11	1	12
12	Tripura	2	–	2
13	Uttarakhand	3	–	3
14	Uttar Pradesh	34	1	35
15	West Bengal	11	3	14
16	Dadra Nagar Heavily	1	–	1
17	NCT of Delhi	2	–	2
Total		147	28	175

1. CWC Report (2013)

The river management wing of CWC operates with the help of regional offices each headed by a Chief Engineer. At present, 14 circle offices and 25 divisions of CWC are actively engaged in flood forecasting activities.

4.2.2 India Meteorological Department (IMD)

India Meteorological Department (IMD) is an apex organization in the Government of India actively involved in weather forecasting and early warning in association with the Central Water Commission (CWC). Established in 1875, the organization is a leading meteorological service provider in the country with specialization in hydrometeorology, seismology, and allied subjects (India Meteorological Department, Government of India).

IMD supports CWC in formulating flood forecasts of different river basins by way of providing various meteorological inputs like Quantitative Precipitation Forecast (QPF) for 24 h and weather condition and the rainfall probability forecast warning for 24–48 h period. There are 10 flood meteorological offices located in Agra, Ahmadabad, Asansol, Bhubaneswar, Delhi, Guwahati, Hyderabad, Jalpaiguri, Lucknow, and Patna that provide region-specific weather information to flood control rooms and forecasting stations.

In addition, IMD also has the specialization in short-range weather forecasting by using Doppler Weather Radar (DWR). The DWR data are useful in numerical weather prediction models for better estimation of rainfall. The velocity and spectrum width data of DWR can provide weather forecast information in detail. The functioning of Doppler Radar is based on the principle of Doppler's effects. In case of relative motion between the source of the electromagnetic waves and the target, the waves reflected from the target has the change in frequency as compared to the transmitted waves. This change in frequency is called ‘Doppler Shift’ that is directly proportional to the relative velocity between target and the source of the electromagnetic waves. The DWR is operational round the clock in auto acquisition mode. The range of surveillance is 500 km; however, for the purpose of structural analysis, the range is 300 km. In India, there are six DWR installed along the east coastal regions viz. Chennai, Karaikal, Machilipatnam,Visakhapatnam, Paradip and Kolkata. One at Gopalpur is likely to be installed shortly. A Doppler Radar is installed in Mumbai in the west coastal region with three more at Kochi, Goa and Bhuj likely to be installed shortly. There are 11 DWRs installed in the inland locations in India at Agartala, Bhopal, Hyderabad, Jaipur, Lucknow, Mohanbari, Nagpur, New Delhi, Patiala, Patna and Srinagar. The DWR can be useful in the following observations:

• Amount and rate of rainfall

• Cyclone intensity and wind speed

• Direction and speed of the movement of thunderstorms, tornadoes and cyclones

• Expected storm surge height, potential destruction, etc

There are various IMD centers of prime importance operational through Delhi headquarter that provides support in weather forecasting and early warning- 

• (A) National Weather Forecasting Center (NWFC) is an integrated and automated wing of IMD that provides services in all types of weather forecasting as well as advisory support to all its regional and state offices. The center is based in IMD headquarter, New Delhi, with backup support server at IMD Pune. There are various under mentioned cells of NWFC, which generate weather forecast information by using GIS-enabled modeling software.

  • General forecasting cell

  • Aviation cell

  • Public weather service and multi-hazard monitoring cell

  • Cyclone warning and marine cell

  • Radar and satellite application cell

  • Nowcasting cell

  • Numerical weather prediction cell

  • Hydrometeorology cell

  • Agrometeorology cell

  • Climatology cell

    The products are used by different agencies working on different disasters.

4.2.3 National Centre for Medium-Range Weather Forecasting

National Centre for Medium Range Weather Forecasting is engaged in medium-range weather forecast and climate modeling through research, development, and application of advanced technology. The center uses various forecasting models like NGFS, NCUM, NGEFS, and VSDB for generating wind forecast, rain forecast, MSLP, meteogram, trajectory, dust forecast, temperature change forecast, etc. for India as well as Africa, Afro-Asia, Southern Ocean, and Antarctica (ncmrwf.gov.in). The products are used in operational forecasting by organizations like IMD, Indian forces, Snow and Avalanche Study Establishment (SASE), Bhabha Atomic Research Centre (BARC), Indian Institute of Tropical Metrology (IITM), Pune, INCOIS, etc.

4.2.4 State Agencies

In addition to CWC and IMD, there are few agencies in some of the states which are involved in weather forecasting and early warning through automatic weather stations (AWS). The information generated through these agencies is useful in the prediction of flood occurrence in the concerned river basins. At present, the states of Andhra Pradesh, Karnataka, Bihar, Tamil Nadu, Odisha, Rajasthan, etc., have established their automatic weather stations either on application or experimental basis; the details about few of them like Karnataka, Andhra Pradesh, and Bihar are as under.

• (A) Karnataka State Natural Disaster Monitoring Centre

The government of Karnataka has established Automatic Weather Stations through Karnataka State Natural Disaster Monitoring Centre based in Bangalore. The automated and timely weather alerts and forecasts are helping farming communities as well as policy planners, including disaster managers to a great extent. The most significant feature of the system is automated generation of weather-related data and instant dissemination to user communities through electronic communication media.

The scope is focused on the real-time weather monitoring, data analysis, vulnerability mapping, risk assessment, report generation, and disseminating information to users (source-KSNDMC).

In the current AWS system, a dense network of GPRS-enabled solar-powered telemetric rain gauge (TRG) stations covering all the 5625 g panchayats and telemetric weather stations at all the 747 hoblies (cluster of few gram panchayats) have been designed and installed in Karnataka. Thus there is a rainfall monitoring station at every 250 km² in the state (source-KSNDMC).

The organization, with the help of TRGs and advanced software, generates data on rainfall, dry spells, aridity anomaly, agriculture sowing status, crop condition status of the major reservoir levels, etc. The accumulated reports are generated automatically at KSNDMC and disseminated through e-mails, SMSs, etc., to the concerned government officers and community dwellers.

An interactive help desk Varuna Mitra has also been established by KSNDMC to disseminate weather-related information, forecasts, and advisories to farming communities and the general populace. An AWS-based project on urban flood monitoring and management has been undertaken by KSNDMC for the city of Bangalore. The aim is to provide alerts and early warning to Bangalore Municipal Authority (BMA) for onward dissemination to citizens of Bangalore.

In the current system, automated data on the intensity and amount of rainfall is collected at every 15 min interval. Forecast information is generated at KSNDMC by using such data that are sent to concerned government officials of Bruhat Bangalore Mahanagara Palike (BBMP) through SMSs and e-mails.

During the situation of high rainfall, a High-Intensity Rainfall Alert (HIRA) is automatically generated and sent to these officials through the same media. Hourly rainfall maps are also generated, which are useful in rainfall variability analysis (source-KSNDMC)

• (B) Andhra Pradesh State Development Planning Society

The state of Andhra Pradesh has established Integrated Flood and Cyclone Warning System by using automatic weather stations (AWS). The system is developed and implemented by Andhra Pradesh State Development Planning Society (APSDPS) based in Hyderabad.

The real-time flood warning system is being implemented for 24 river systems, including rivers like Pennar, Krishna, Godavari, Nagavali, and Vamsadhara covering a total area of 6.85 lakh square kms. The APSDPS, with the help of automatic weather stations, capture spatial and temporal rainfall data that are used for forecasting rainfall in advance for next 48 h using weather forecasting models. The forecasted rainfall data is then converted into runoff forecast by using hydrological models. This gives an estimate about the potential water levels in the rivers at certain time interval. For this purpose, the MIKE-11 hydrodynamic model is used. The obtained data is finally loaded in the MIKE GIS software to generate potential inundation map of the area 48 h ahead of the event. This may enable local administration, policy planners, and local communities to respond appropriately to the emerging situations. The various models used for generating forecast data are hydrological models (for runoff estimation), hydrodynamic models (flood forecasting), and rainfall atmospheric model (precipitation estimation).

The system is providing support to the state government in getting real-time flood forecast information for the next 24 h, runoff estimation, rainfall forecast, potential areas likely to be inundated during high rainfall, etc. (source-APSDPS).

• (C) Flood Management Information System (FMIS)

The Water Resources Department, Government of Bihar has established a network of flood forecasting and inundation modeling and information system with the help of World Bank known as the Flood Management Information System (FMIS). The main objective of this system includes long-term objectives of developing and implementing a comprehensive information system to support policy planners and administrators of flood-prone areas. The other objectives are to develop flood hazard characterization and operational flood management information products, updated flood control manuals, etc. The system is based on technologies of GIS, remote sensing, rainfall forecast modeling, etc. FMIS may be extremely useful in the state in terms of providing rainfall forecasts; flood forecasting and inundation predictions; flood hazard zonation mapping; hazard, vulnerability, and risk analysis; etc. The system is being installed in a phase-wise manner in the state covering most vulnerable and vulnerable flood districts like East Champaran, Muzaffarpur, Begusarai, Samastipur, Darbhanga, Sitamarhi, Sheohar, Madhubani, Supaul, Saharsa (first phase) and Patna, Bhagalpur, and Munger districts (second phase).

5 Flood: Hazard and Risk Management

While defining flood, two main concept emerges out to understand – firstly flood is the phenomenon of water, streams, and rivers in a particular area and secondly no flooding may occur if the water is easily and quickly drained out or managed. Hence the concept of flood as a hazard should also incorporate these two points. The dimension of flood has different connotation for different countries in the world. The annual flood in the river Nile in Egypt is considered as the gift of God, which brings life and prosperity in the form of water and fertile silts for the people of Sahara deserts; the similar natural phenomenon brings a calamity somewhere in other parts of the world including India.

It is significant that regions where flooding gain the status of calamity are those where society or community gets affected. Flooding in uninhabited regions does not affect the society and therefore human concerns are less, whereas the same phenomenon that occurred in populated regions seriously affects the society and ultimately gains the status of disaster.

Flood as a disaster has long been a matter of concern for policy planners in India as it brings benefits as well as losses for communities. The annual floods in the Indo-Gangetic plains maintain the fertility of soil by depositing silt containing different minerals carried out from different parts of the mountains. They bring additional water for irrigation, thereby contributing to enhanced fertility in the region, whereas the same flood in larger dimension or in unprecedented situation seriously affects communities living in the floodplain or low-lying areas. In other parts of the country, the flooding occurs due to heavy torrential rainfall combined with poor drainage, that causes disasters in the society resulting in the loss of lives populations and infrastructures. The recent examples are Uttarakhand flood (2013) and J&K flood (2014).

In order to prevent this hydro-meteorological phenomenon attaining the status of disasters, there is a need to adopt a comprehensive, integrated, and scientific approach. Flood disaster management approach is essentially required in India because it affects the normal functioning of societies or communities, but above all, the optimal utilization of land and water resources is of vital importance to bring prosperity in the country.

On the account of unique and varied geo-climatic condition right from the extra peninsula in the north to peninsular tip in the south and from Arunachal Pradesh in the east to the extreme western Thar Desert, the nature and scope of flood risk varies greatly; therefore the risk management strategies and disaster management plan during the flood disaster must address all the topographical, geographical, and climatic conditions to effectively combat the potential threats.

The “National Water Policy” has suggested that there should be a master plan for flood control and management, for each flood-prone basin. It is essential to promote watershed management practices through water management, soil conservation, catchment area development, etc. to reduce the intensity of floods.

The systematic approach of flood management and mitigation in India at the policy level was started by the Government of India in the year 1954 after the unprecedented floods in different parts of the country. A policy statement by the Ministry of Planning, Irrigation, and Power was placed before the parliament under two separate categories – “floods in India (problems and remedies)” and “the floods in the country.” The objective was to suggest a comprehensive framework for the management of flood disasters in the country. Since then, various committees have been constituted from time to time to suggest recommendations, strategies, and policies on various flood management and mitigation issues. The list of all the committees/working group constituted since 1954 is as under (Table 20.17).

Table 20.17 Agencies constituted for flood management (1954–2004)

Though several good policy initiatives were taken by the government of India to minimize the menace of floods in the country, the one which is of greater significance was the constitution of Rashtriya Barh Ayog (RBA). In 1976, the government constituted RBA under the chairmanship of Mr. Jaisukhlal Hathi, the then governor of Punjab/Haryana, to look into the contemporary situation of floods in the country and to carry out in-depth study of the long-term flood management approach. This was the most comprehensive study of flood carried out by any committee since independence. It looked into various flood problems and submitted its report in 1980 with 207 recommendations covering almost all the aspects of flood management. However, the implementation of recommendations by different states remained mostly under the slow pace. In order to review the progress of implementation of RBA, few committees were further constituted including an expert committee setup in 2001 by the Ministry of Water Resources under the chairmanship of Sri R. Rangachari. The committee reviewed each of the recommendations of RBA and opined that its implementation has been slow which requires more attention by the concerned stakeholders. The committee further suggested 40 out of 207 recommendations to be taken up on priority basis.

In many of the recommendations listed in previous pages by different committees/commissions, it was strongly felt that practically it is not possible to protect all areas against high flood and structural mitigation measures alone cannot be considered as appropriate for flood management, there should be a combination of both structural and nonstructural measures on flood mitigation, so that overall losses could be minimized. The flood management measures can be classified into the following categories and subheads as under.

5.1 Flood Prevention, Preparedness, and Mitigation

Flood is a natural phenomenon of rivers and channels at the time of high discharge that cannot be prevented or checked through human interventions; however, its impact in the form of disasters may be prevented to a greater extent through better response planning, preparedness and mitigation approach. Disaster prevention, preparedness, and mitigation are such measures through which potential disaster threats can be minimized or even prevented (Ghosh 1997).

5.1 20.5.1.1

There are various preventive measures, which, if adopted in a right manner, at the right time, and at the right place, can avert the threats of potential disaster situations. The flood prevention measures can be the combination of both structural and nonstructural measures as mentioned below:

• (A) Rainfall Runoff Balance  – A complete balance of rainfall-runoff can be the best preventive measure for flood hazards. Due to the occurrence of high-intensity rainfall, resultant runoff becomes heavier and faster, which decreases the carrying capacity of rivers with resultant flooding in the adjoining areas. A large-scale catchment area treatment, including Afforestation and reforestation, may delay the surface runoff to reach river channels, thus minimizing the risk of flood disaster. The forest and vegetation cover can be helpful in a number of ways which includes delaying surplus water to reach river channels. They can promote infiltration of rainwater, thus preventing threats of flood as well as saturating groundwater. Forest and vegetation cover can also reduce soil erosion, thus preventing silts to be deposited in the river beds, thus increasing the water carrying capacity of rivers.

• (B) Smooth flow of discharge through river channels – Developing smooth flow of discharge through river channels may be a good option for flood prevention, provided the socio-economic viability is ensured. This includes making meandering course of rivers straighter and linear, so that flood discharge may move downstream more rapidly. This was successfully experimented in 1933–1936 in river Mississippi (USA) near Greensville and on the river Missouri (USA) in Sioux city.

• (C) Detention of surplus water – The flood storage reservoirs and detention basins are the structural measures of flood prevention that reduce the volume of water to reach river channels at the time of high discharge thus averting threats of disasters. The construction of reservoirs and detention basins helps in retaining surplus waters during peak flow, thus reducing threats of floods in downstream areas. In addition, the stored water may also be used for the purpose of irrigation and drinking water. The Tennessee Valley project in the USA and Damodar Valley project in India were undertaken for multipurpose utility, the prime being flood control (Sinha and Sinha).

• (D) Diversion of excess water to deficit regions – At the time of high discharge, there is a need to divert flood water in low-lying areas, depressions, or secondary channels so that excess water may be used for other purposes and can be transferred to deficit areas. For example, Ghaggar Diversion Scheme in Rajasthan had used to divert about 340 cumecs of water discharge to a low-lying depression before entering Rajasthan.

5.1 20.5.1.2 Flood Preparedness

The preparedness for flood is an integral and most crucial element of the flood management plan which aims to minimize the adverse impact of flood hazard through effective precautionary measures and to ensure effective response at the time of disaster. The primary responsibility of flood preparedness in India lies with the state and district administration to make preparedness plans based on risk assessment and vulnerability analysis of floods. The following preparedness measures should be undertaken in any flood management program:

• State Authorities and the district administration should regularly check the early warning notices issued by the India Meteorological Department (IMD) and flood forecasting information issued by the Central Water Commission and other agencies.

• State governments or State Disaster Management Authorities must take prohibitive action for the blocking of natural drainage channels and sluices through appropriate policies and laws and also to improve their capacities and construct new channels and sluices to ensure the flow of excess rainwater in the area.

• In flood-prone areas, buildings constructed of earth, weak foundations, and water-soluble materials may collapse and endanger human lives and properties. Such structures may be checked in advance, so that precautionary measures can be taken in advance.

• During excessive rainfall, especially in hilly areas, physical damage in the form of landslides may occur. In addition, some structures may also get damaged due to high-intensity flowing waters. Such areas may be demarcated with the adoption of suitable mitigation strategies.

• Flood preparedness programs should be conducted at the community level, which may comprise of awareness campaigns, mock drills, NGO coordination, resource management, etc.

• District administration in the state should review the existing danger levels and warning levels in their districts, and if required, these level marks should be updated.

• Pre-monsoon inspection of rail tracks, roadways, canal networks, and drainage networks should be conducted periodically.

• In order to prevent outbreaks of epidemics and viral infections, well-coordinated medical preparedness strategies must be adopted well in advance, which may include stocking of emergency medical equipments and medicines and availability of medico and paramedic staffs.

5.1.1 20.5.1.3 Flood Mitigation

The flood mitigation measures are broadly categorized into Structural and Non-structural based on the kind of interventions. In structural mitigation measures, the emphasis is toward “preventing flood from affecting the society or population,” whereas nonstructural mitigation measures aim to “keep people away from the flood.”

A. Structural Mitigation

This involves the process of constructing structures along the rivers or areas which are annually or perennially affected by floods in order to make rivers flow in a guided manner so as not to cause much damage during high discharge. Some of the prominent structural measures are as under:

• 1. River Training Works are types of engineering interventions applied on rivers to regulate and control the flow to river channels and river bed configurations, smooth navigation, control of sedimentation, etc., thereby contributing to flood protection, prevention, and mitigation in the catchment area. This is considered as one of the effective structural measures of flood management. The construction of dykes along the river Ganges for protecting adjoining cities from flood threats was an earlier attempt in the country to adopt river training works. This is considered as one of the successful techniques of preventing sedimentation and river bank erosion in perennially flood affected areas in Assam and Bihar.

There are various types of river training works that are considered helpful in flood management. They are Bed Bar, Bank Protection and Pitched Bank, Guide Bank System, Groins or Spurs, Deflectors, etc.

Transverse structures	Longitudinal structures
Check dams, Spurs, Sills, Screen dams, Porcupines, etc.	Embankments, Levees, Guide banks, Revetments, etc.

The river training structures are broadly classified into two types based on the alignment of structures with respect to rivers – transverse structures and longitudinal structures.

Transverse Structures

• (i) Groins or Spurs are structures constructed in such a way that one part of it is projected toward the river course. They are also known as Spur Spur Dykes, Transverse Dykes etc. This is primarily useful for providing a directional flow to rivers and preventing river bank erosion. The “backward” sides of spurs are zones of moderate to slow flow, which promote siltation in between two spurs thereby creating natural banks along the river.

• (ii) Sill is a transverse structure constructed on the river bed across the river to reduce downward erosion. This can be of different shapes and materials depending upon the utility of the structure and availability of materials

• (iii) Check dams are constructed across rivers to stabilize the flow of river channels. These structures decrease the morphological gradient of the torrent bed and reduce the water velocity during a flood event by increasing the time of concentration of the hydrological basins and reducing the flood peak and solid transportation capacity of the river (Shrestha et al. 2012).

• (iv) Sediment retention structures are created across rivers to filter debris, boulders, and other sediments reaching downstream through flood waters. Whereas the structure like beam dam is constructed to retain sediments and silts, screen dams are used for filtering materials like wood, tree trunks, branches, etc.

• (v) Porcupine structures are useful for retarding the flow of water during peak discharge, thus helping to reduce river banks and bed erosion. They are designed mainly by timber or bamboo in such a way that they are protruded in different directions; however concrete structures are also in use. The common shapes are tetrahedral and prismatic (Shrestha et al. 2012).

Groins on river Narayani, Nepal (Source – northstarnepal.com)

Longitudinal Structures

These are technically designed structures constructed along the river course for providing protection against river bank erosion, inundation in low-lying areas, and preventing rivers from meandering its course. They are of the following types:

• (vi) Embankment or Levee is an earthen longitudinal protection structure, constructed along the course of river channels in such a way as to protect the area behind it from the overflow of flood waters. In India, since 1954, about 35,200 km of embankments have been constructed by March 2011 (XII plan report, GoI). Some of the rivers like the Ganges, Gandak, Damodar, Mahanadi, Godavari, Krishna, and Cauvery are known to have been protected by embankments on a larger scale.

  The highlands or high ridges along the rivers are considered as suitable for the construction of embankment provided the soil and ground conditions are suitable. They should also be maintained and protected after construction to avoid any further disasters. In case an embankment is likely to be collapsed or likelihood of flood is more, a loop bund is constructed behind the embankment to provide a second line of protection.

• (vii) Bed bar is a submerged longitudinal structure which divides the flow horizontally in two parts. The flow above the bed bar follows the weir flow, whereas the flow below the top level is obstructed by the bar and diverted toward the nose.

• (viii) Bank protection structures are artificially constructed surface on river banks or slopes, designed to absorb energy of water waves and to protect them against erosion. Revetment is one of the most common structures of river bank protection wherein artificial slopes or surfaces are created along the bank. This can be done through “rip rap” which is a kind of arrangement of loose rocks or boulders to make the revetment structure.

• (ix) Guide banks, as the name denotes, are embankment-like structures constructed on rivers to guide the flow of rivers or in other words to provide a directional and controlled flow of rivers. The guide bank system works on the principle that a flood partially controlled and directed by the groins should confine in a directional flow to ensure its safe passage without destroying the river banks or other structures.

• 2. Flood proofing is the long-term measure to mitigate the effects of flooding through modification of building and other infrastructures in the immediate surroundings of flood-vulnerable locations in order to minimize the damage due to flood.

B. Non-structural Mitigation

This involves planned activities to mitigate the adverse impacts of flooding without undertaking any structural changes/modifications. Unlike structural measures, this aims to adopt strategies for keeping people away from the flood vulnerability. Some of the common non-structural measures are as under:

• (i) Flood forecasting and warning is the most common and important mitigation measure being adopted in India. This has already been discussed in the previous pages of this chapter.

• (ii) Floodplain management is one of the major thrust areas of government’s flood management programs, wherein more emphasis is on the developmental activities in floodplain areas, to make them encroachment-free to minimize flood damages. The objectives of such programs are:

  • To reduce future potential damage in floodplain and adjoining locations

  • To develop strategies for maximum utilization of floodplains for developmental activities during non-flood peak periods

  • To regulate and control floodplain through regulations, by-laws, building codes, policies, etc.

5.2 Flood Response and Rehabilitation

Flood response measures are activities undertaken at the time of flood occurrence or at the time when flood threats are imminent. The response measures undertaken by responder teams/organizations are usually planned, organized, coordinated, and effective at all levels, so that the affected communities get adequate relief at the time of calamity. In India, flood response measures are undertaken at different levels depending upon the severity of floods. In order to have a better management and control over the situation, it is essential to identify the scale of response required and the role of various responders right from the national level to the district and the village level. At the time of flood emergency, institutionalization of the system had to be properly managed at various levels. The response activities should not be confined to a single organization either by the government body or the private agencies, but this should be made as multi-organizational with close coordination of multiple stakeholders.

The role of communities as first responders is now an established fact. After any flood disaster, the community responders primarily extend their support with all the available resources; thus any response plan must take into consideration the role of community responders. The local volunteers must be trained by National Disaster Response Force (NDRF) and district/state training institutions in various skills of flood response in each district with basic training in search and rescue, medical first aid, CPR, etc. The community volunteers thus trained can assist in planning and setting up emergency shelters, distributing reliefs, identifying missing people, and addressing the need of education, health care, water supply and sanitation, food, etc. In addition, community level organizations like NGOs, Self Help Groups, community-based organizations, National Cadet Corps (NCC), National Services Scheme (NSS), Nehru Yuva Kendra Sangathan (NYKS), women’s group, civil defense, etc., volunteer their services during flood and other disasters. Thus, there is a need that various task forces may also be constituted through active involvements of these stakeholders for inculcating a culture of preparedness to respond at the time of flood. The community-based preparedness and response planning coordination are required among various agencies as under:

The flood response comprises a sequence of activities undertaken by a group of experts or skilled people or even unskilled community dwellers to carry out search and rescue of victims, mobilization of equipments, resources, and services. A successful response planning requires immediate planning, mobilization of resources, quick activation of essential functions etc.

During the situation of all the disasters, including floods, the response planning is strategically designed based on the severity of disasters and the ability of response authorities to deal with the situation. Accordingly, disasters are categorized as L0, L1, L2, and L3 type (source-ASDMA).

Response severity level	Characteristics
L0	Normal times
	Stage to carry out prevention, preparedness, and mitigation activities
	Stage of research, documentation, and monitoring and planning
	State authority should focus on training and capacity building intervention
L1	Disaster severity is at the district level, which may be managed by the district authority at the district level
	State and central authority must be in readiness to provide assistance if required
L2	Disaster severity has expanded to more than one
	State intervention may be required
	Assistance may be provided from the state headquarters
	Central authority must be in readiness to provide assistance if required
L3	Disaster severity is large which is beyond the capacity of district and state administration to provide adequate response
	Central government intervention may be required
	Central assistance required (courtesy – asdma web site)

Immediately after receiving early warning information, the evacuation is required to be undertaken in a systemic manner. The successful evacuation planning for population and livestock is considered as the only means to save them from flood disasters. Evacuation planning for a larger group of population becomes a difficult task, which required effective Incident Response System to be in place. Responsibilities are to be fixed for each stakeholder in the form of Standard Operating Procedures (SOPs). The successful evacuation depends on a continuous dialogue with the following stakeholders:

The response activities should be carried out with preliminary estimation of the flood situation by studying the flood level data and inundation data received from satellites. This may help policy planners to undertake focused response activities at the right location at right time. While carrying out response activities, effective media management also plays a greater role. The state government may utilize different types of media, viz., print, electronic, and other social media to disseminate early warning of flood occurrence in any locality. This may help authorities to undertake smooth response operations. In addition, last mile connectivity is also ensured with the help of local administration and community-based organizations. Thus the effective response planning is much required in order to have a better culture of prevention, preparedness, and mitigation.

6 Role of Geographical Information System (GIS) and Remote Sensing (RS) in Flood Risk Management

The Mitigation of flood hazards can be successful only when the detailed knowledge is obtained about the expected frequency, character, and magnitude of hazardous events in an area as well as the vulnerabilities of the people, buildings, infrastructure, and economic activities in a potentially dangerous area. Remotely sensed imagery and the Geographical Information System (GIS) can be very effective in identifying the spatial component of flood for its better management. Remote Sensing offers a synoptic view of spatial distribution and dynamics of hydrological phenomena such as flood and River Erosion. They are used to measure and monitor the extent of flooded areas and provide a quantifiable estimate of the land area and infrastructure affected by flooding and erosion.

GIS may be defined in different ways, but the most commonly used definition is that provided by Burrough (1986) generally known as “tool box definition.” He defined GIS as a powerful set of tools that enables collection, storage, retrieval, analysis and presentation of geographically referenced information. Remote Sensing (RS) on the other hand is defined as the science of acquiring information about the earth’s surface without actually being in physical contact with it. The transfer of information is done using electromagnetic radiation with the aid of sensors. The Remote Sensing plays greater role in the development of GIS, both as a source of technology and as a source of data. Together with RS and modeling, GIS provides a wide range of applications in agriculture, geology, natural disaster management, hydrology, weather monitoring, business and service planning, government, logistics, and transportation and environmental management.

The role of this technology is vital in flood management as the information on the predicted flood extent is required by the government, the public, and the emergency departments in order to facilitate early preparations and plans well in advance before the actual flood event. Early preparations and planning result in the effective and efficient response, thus minimizing and/or mitigating the after flood effects. There has been widespread development in the use of hydrological models with a flood prediction component. These models are in most cases, either loosely or tightly coupled with GIS and remotely sensed data. Most of these models require different types of data input such as land cover, land use, river discharge rate, rainfall amount, surface roughness, Digital Elevation Models (DEM), and size of drainage basin, among others. In this case RS techniques can be used to obtain spatial and temporal information needed for parameterization of the distributed hydrological models. The general idea is that RS and GIS provide spatial and temporal data input required by the distributed hydrological models in order to simulate runoffs and thus floods. Remote sensing (RS) data in some studies have also been utilized to calibrate and improve the performance of distributed hydrological models. The REmote Sensing techniques provide an option of accessing information from otherwise physically inaccessible areas. GIS tools have been imbedded in the hydrological models to facilitate in data analysis, querying, and presentation of information in a more simplified way; thus they form a critical part of the distributed hydrological models used for flood prediction.

One of the key stages in flood management is the identification of areas with potential flood risk that is the product of flood hazard and vulnerability. Mapping of flood risk areas is not only important for the location of potentially hazardous zones but also for government, nongovernmental organizations (NGOs), and other planners to get an idea of where priority should be given while allocating resources. Evacuation agencies, insurance companies, and relief providers also require knowledge of spatial extent of inundated areas. This could be information about roads that may or may not be passable, worst affected areas, and areas suitable for camping during flood periods.

The Remote Sensing and GIS techniques have been proved resourceful at different stages of flood management. For example, areas of potential flood risk were able to utilize the overlaying function of a GIS to combine land cover maps with the flood-predicted zones. The resultant maps provide simplified information on the flood hazard (depth, velocity, direction of flow), elements at risk, their exposure, and vulnerability. In addition, flood hazard, vulnerability, and risk maps were drawn showing areas of low or high flood risk.

The GIS and modeling approaches, in particular, have been used in investigating the possible effects of land use changes during flood. Land use scenarios and their possible impacts in the generation of runoffs and consequently flood management may be useful. This may also be helpful in developing policy guidelines and recommendations for urban planning, land use planning, as well as settlements and types of buildings. In this way, flood impacts can be prevented or even mitigated.

The adequate knowledge of damage inflicted by flood is essentially required by the authorities and insurance companies in order to draw policy for compensation as well as to have an estimate of the cost of reconstruction. GIS has a function of overlaying layers and through this function, layers on inundated areas can be overlaid with land use maps, land cover layers, and infrastructure layers, among others. Remote sensing tool can be used for obtaining images before, during, and after flooding. These images are thereafter processed and analyzed in order to obtain information of land cover, buildings, roads, schools, and other infrastructures of the area under normal hydrological conditions (before flooding), inundated areas and flood extent (during flooding), and flood effects, deposits, and debris (after flooding). When the comparison of these images together with a pre-flood data is carried out, the extent of flood damage can be estimated.

In spite of the great potential that RS and GIS offer in flood management, their use has been limited to some extent. The presence of cloud covers during flood periods has been reported as the major challenge in the use of optical remote sensing in flood management. Using Synthetic Aperture Radar (SAR) is a better option since radar pulse has a higher penetration power to overcome the problem of cloud cover; however, its use, especially in developing countries, has been constrained by its high prices as well as limited coverage. One of the most pressing challenges of remote sensing technology is limited availability of imageries in time and space, seasonal variations, technical limitations, and above all the problem of low temporal resolution. With reference to the problem of temporal resolution, most radar images take some time before and also after the flood and in most cases the flood peak may not be captured. In other words, there is a time delay between the actual time the flood occurs and the time when satellite images are taken. Most of the current radar satellites have a long revisit time that can be up to 35 days. There are other challenges too in the application of GIS technology in natural disaster mitigation. These include high cost of digitization and raw data collection, the intrinsic complexity of predictive models, lack of appropriate raw data, inadequacy of hardware technology to handle large spatial data sets, and difficulty in GIS to manage historical data necessary for some natural hazard assessments. However, the technology has a great prospect in the country that may create revolution in the field of flood management.

7 Do’s and Don’ts

Time	Phase	Do’s	Don’ts
Before	Prevention	Design your houses as structurally flood proof	Don't encroach river channels and floodplain with illegal constructions
		The height of the plinth should be raised above the historic flood level	Don't cut trees & forests in the flood-prone areas. This may loosen soil and may cause river erosion and consequent flooding
		Always keep river channels and floodplain obstruction-free	Stop Deforestation, promote reforestation and afforestation
		Consider producing flood resistant crops	Don't cover topsoil layer with concretes/metallic surfaces
		Promote/encourage afforestation/reforestation in areas of flood vulnerability	Don't encourage river aggradation or degradation
		Keep some areas open for percolating excess runoff	Don't promote activities which may weaken the strength of embankment
		Maintain the depth of river channel to accommodate excess water at the time of flood	Don't compromise with the quality of materials for the construction of river training works
		Consider making strong embankments in the flood-prone areas. Embankment should be aligned on the high ridges or natural banks of the river, where land and soil is suitable	Don't release debris, concrete materials, or solid wastes in river channels which may obstruct the flow-causing floods
		If you are a policy planner/engineer, consider applying river training works like construction of groins, deflectors, and bed bars to confine and regulate the flow of river channel
		Debris or concrete or solid wastes should be disposed off suitably without disturbing river ecosystem
	Preparedness	Get information about the safe evacuation routes of your community to reach the nearest shelter	Don’t keep these items preserved for longer duration. Replace them after 6 months with fresh items
		Keep an “emergency kit” ready. The kit may contain:	Don’t give importance to rumors
		Torch with spare batteries	Don’t be in panic
		Candles and match boxes
		Bottle of fresh water (pref. sealed bottled water)
		Bottle of kerosene oil
		Portable radio with spare batteries
		Dry foods
		Umbrella and rain coats
		Gum boots
		Salt and sugar
		Keep your “first aid and medication kit” ready. The kit may contain the following items:
		Essential life savings medicines
		Packets of ORS or electrical powder
		Adhesive bandages of various sizes (20 nos.0
		5 × 10 in. sterile dressings
		Gauze roller bandage (2 nos.)
		Triangular bandage with safety pins (2nos.)
		Sterile gauze pads 4 × 4 in. and 3 × 3 in. (1 pkt each)
		Antiseptic wipes
		Hand sanitizer
		Latex gloves (disposable)
		Adhesive tapes (25 × 5 mm)
		Non adhesive absorbent pad (7.5 ×10 c.m)- 4 nos.
		Saline solution (30 ml)
		Wound dressing with bandage (1)
		Ambu bags
		Thermometer
		Chlorine tablets, etc.
		Always keep a watch on the expiry dates of these items. Replace them with fresh items after a certain period
		Keep a waterproof bag ready with all your essential documents, photo ID cards, valuables, personal papers, etc.
		Make an indoor plan of your house indicating which items would be raised or managed if water enters in your house
		Be a regular listener/viewer of local news from radio/TV for warning and advice
		Gather regular updates on flood warnings from local authorities like gram panchayats, BDO/Tehsildar office, weather stations, etc.
During	Leaving houses	Ensure all your personal essential items are packed in waterproof bags	Don’t forget to take personal kit, emergency kit, and first aid medication kit with you
		Intimate your neighbors/friends/local volunteers about locations you are shifting to	Don't keep yourself and your family empty stomach. Take light foods at regular interval
		Display your contact number on your house wall, so that you may be contacted in case of emergency
		Raise all wooden furnitures, carpets, clothings, and other valuables onto the top of the roof under shed or at higher places to avoid contacts with flood water
		Turn off all electricity/power switches and main power supply. Unplug all electrical gadgets
		Insert sandbags in toilet bowls and all drainage inlets/outlets to prevent backflow of sewerage/floodwaters
		Lock your home cautiously. Move through known evacuation routes
		Always spray disinfectant, bleaching powder, etc., to keep your surroundings free of infection
		Extend helping hands to government officials/volunteers distributing relief materials
	Health care	Always use boiled water for drinking purpose
		Keep all eatables covered
		Don’t take heavy meals
		If exposed to diarrhea, ORS solution, rice water, etc., should be taken on periodic intervals
	Emergency shelter	Immediately rush to higher places preferable at railway tracks or highways
After	Returning home	Update yourself with the local situation through radio/TV	Prevents children to play or roam in flood water
		Check and repair all electrical appliances before using them	Don't enter receded water of unknown depth
		Eat only fresh foods or sealed foods
		Before getting supplied pure water, use boiled water by your own
		Snake bites are common during and after floods. Be careful
		Always keep antivenom with you