Flood Frequency and Mitigation in India

Chapter 1: INTRODUCTION

1.1 Research Background

Over the years, flood frequency and intensity in the country have grown largely due to increasing flooding in the country. Interestingly, while the number of people affected and economic losses caused through flooding have decreased over the last decade. Such patterns need enhanced national, regional and local preparation to ensure appropriate and efficient action during flood emergencies to mitigate life loss and property damage (Ahern et al., 2005). In India, approximately 75 % of the total rainfall occurs over 4 (June-September) months of monsoon and thus almost every river is heavily dumped in these four months. Roughly 12 percent of the country’s area is vulnerable to flooding, with an annual average fluid of about 40 million hectares and about 8 million per annum. Brahmaputra, Ganga and the Meghana basins are the most vulnerable to floods (ArcGIS Resources, 2012). The States include Uttar Pradesh, Bihar, North West, Assam, and Orissa. Late floods in the states of Andhra Pradesh and Gujarat have also become a serious business. Every year, more than 30 million people are displaced (Adeoye, Ayanlade & Babatimehin, 2009). In recognition of the need for the hour, the 1990-1999 decade was declared the "International Decade for Natural Disaster Reduction." Its main goal was to focus on disaster management planning to prevent, reduce, mitigate, prepare and react to disaster losses (Adedeji, Odufuwa & Adebayo, 2012). The fact that 40 million hectares of land over a geographical area of 328 million hectares is suspected of floods is high risk and vulnerability of India. On average 75 lakh hectares of land are affected every year, 1600 lives are lost and flood damage is roughly Rs 2000 crores caused to crops, houses and public utilities. In 1977 the highest number of people killed (11,316). More than once in five years, there is the incidence of significant floods. Even areas historically not deemed vulnerable to flooding, flooding also took place. In the monsoons from June to September, 80% of precipitation takes place (Aziz, Tripathi, Ole, & Kusanagi, 2002). From the catchments, the rivers bear high sediment. Such, combined with insufficient river transport facilities, causes flooding, drainage congestion, and river bank erosion. Indeed, the problem comes with another complicated aspect in some of the damaging rivers in India. This paper examines the established practices and the current management status and flood preparedness in India (Chang, Shahneela, Khatoon & Ali Shah, 2013). “Disasters do not cause effects; the effects are what we call a disaster” Wolf Dombrowsky (1995) Over quote a message is sent to the effect that the catastrophe is an incident that causes environmental vulnerability. It also means that disaster impacts need to be researched (Burrough, 1986). In today's world, natural disasters are frequent. They are due to sudden changes in the condition of natural elements because of the forces of nature. The bulk of natural disasters is beyond human control and cannot be correctly predicted as they occur (Bernhardsen, 1999). Major natural disasters, such as inundations, seismic disasters, landslides and droughts resulting in the risk of human death, property loss; have an impact on infrastructure, farming and the environment. Due to its intensity and coverage, the impact of the disaster is different. The growing trend of urban floods is universal and presents urban planners worldwide with great challenges (Black, 1996). In a relatively short period of time, urban floods occur and can flood an area several feet away with water. Although water volumes are not as serious as a river system flash flow, property damage and indirect financial losses are significant because of the human control and management of surface water runoff in an environment that is highly populated by people (Adeoye, Ayanlade & Babatimehin, 2009). "More floods which have only happened before, on average every 100 years, can now begin every 10 or 20 years," said the Environment Agency 'S sustainable development unit in June 2001. The flood season can be longer and in areas that have never been there will be floods.

Urban floods differ significantly from rural floods as urbanization results in developed catchments that raise flood levels from 1.8 to 8 times while flood volumes are up to 6 times higher. Therefore, due to faster flow times, in a matter of minutes sometimes, the flood occurs very quickly. Urban areas are centres with vital infrastructure that must be protected 24x7.Water must follow the prescribed paths in urban areas through large water systems that direct the water to flow (Adeoye, Ayanlade & Babatimehin, 2009). The basic philosophy of FEMA is to redirect water flows at an individual site by removing excess surface water as soon as it is possible as a result of rainfall and containing and disposing it as fast as possible by a closed / open conveyance system, according to urban drainage systems or storm water management. In other words, the overly philosophical concept of creating drainage systems in urban areas was "going out of it NOW."

The most frequent natural disasters occurring in humans and the environment are floods (Hewitt 1997). Asia and the Pacific are most vulnerable. It affects a country's social and financial stability. In China there have been many floods, 223 million people were affected by the worst flood in China in 1988, 3004 people were killed, 15 million homeless and over $23 billion were economically destroyed that year. In 2000, 428 people were killed and estimated economic loss over US$ 250 million, due to heavy floods in Cambodia and Vietnam (Hewitt 1997). There were 140,000 deaths in 1991 around the world and 25 million inhabitants in 1998 (UN 2003). Owing to regular flooding in India, Pakistan, Korea, China and Bangladesh over a decade, thousands of people have been affected by floods with their livestock, residential and food supplies in their countryside. The effects of floods are more vulnerable in less developed countries. It has several issues with emergency response and early warning (UN 2003; Chorley 1978). The product of heavy rainfall, snowmelt, Dam failure etc. is a flux or stream that breaks down by natural or artificial river. There are three types of floods: flash floods, fluvial flux and coastal fluxes (GSL 2001). Such flooding influences natural and human participation such as deforestation, land management (wood harvesting, reforestation, herbicide use and controlled burning), industrial development, farming, and river regulation. Recent flood causes in some areas have mainly been caused by unplanned use of land, building and upstream operation of dams. If a hydraulic system is not properly built, the dam will fail, the highway will crash and the bridge will collapse thereby raising the risk of flooding (Gebeyehu 1989). The dam can be disastrous. Yet again, it's human involvement in managing flood disasters by extensive use of various technologies. The use of technology can make it easier for stakeholders to warn early of the floods and to know how the flood will impact (Chorley, 1978). The thesis here tries to concentrate on the environmental impact of floods in the flood-prone area of Panjagutta and Lake Glan. Furthermore, inundated areas should be prepared for the maps and their outputs, which may be used in flood emergencies.

1.2 Aim of the Current Study

The aim of the study is to manage the flood prone areas, with the focus of the Panjagutta and Kairathabad in Hyderabad. This project is hereby intended to construct a flood-risk map in the flood-prone areas (suburbs and communities) in the GHMC. This map further allows: Area-prone stakeholders such as Panjagutta and Kairathabad will engage in disaster reduction and adaptation methods for developing and enforcing effective flood management policies. This also helps to identify regions more resistant to flooding and regions more prone to flooding. The map encourages flood preparedness and immediate evacuation measures if community members are trapped in a storm.

1.3 Problem statement

Hyderabad Flooding – A Case Study of Panjagutta and Kairathabad

Hyderabad City was founded at the southern bank of Musi River in 1591 by Mohammed Quli Qutub Shah. At 536 meters above sea level, Hyderabad lies on the Deccan plateau. The latitude of the city ranges from 17.366 ° N to 78.476 ° E. Hills, tanks, forests and rock formations dominate the city's landscape. The type of soil is predominantly red sandy with black cotton soils interspersed. Records of precipitation from the Hyderabad district's regional planning office indicate that heavy rain months were generally in July, August and September. For normal rainfall, total rain during these months reaches 490.2 mm. The average annual precipitation in Hyderabad is almost 787 mm. For this, almost 75% is from Monsoon Southwest, while the remaining precipitation is the Monsoon North East. In June-September, the city has about 590 mm of rainfall. Due to its exceptional topography of several undulations, rainwater flows quickly to low-lying areas and floods many small areas. Despite of this certain parts of the city have local inundations limited mainly to the low lying areas in the built areas and the tanks on the east side. The fact is that infrastructure and buildings were restricted and this situation was not experienced in the past, possibly due to far fewer inhabitants than in the present level. Because of this, the city has experienced flooding in the last few years due to heavy rainfall.

1.4 Objective & Scope of the Current Study

To identify the reasons and socio-economic consequences of floods for GHMC residents

To analyse the issue of flood in Panjagutta and Kairathabad in Hyderabad and identify the causes behind the problem

To review the adaptation methods for developing and enforcing effective flood management policies if the community members are trapped in a storm and flood

To recommend and improve strategies for the control of floods before, during and after floods for the Panjagutta and Kairathabad case report

The research in this regard provides a scope to analyse the issues related to flood mainly in the Panjagutta and Kairathabad areas in Hyderabad for which the individuals in this area face difficulties in maintaining their standard of living. Through this study, it is also possible to review the existing theories related to flood as well as identify the strategies to manage the issue through evacuation and control in the flood prone areas in Hyderabad.

1.5 Research Hypothesis

Hyderabad became the capital of Andhra Pradesh in 1956 and was migrated on a wide scale from coastal regions, from Rayalseema and elsewhere in the region of Telangana. Poverty was the main factor of this rural-urban migration, given the job chances provided particularly in the ninety's by the rapid growth. Hyderabad City is, according to 2001 census, one of the most rapidly growing metropolises with a decadal growth rate of 32%. Hyderabad City became the second largest municipal corporation in India with a population of 7,000 square Kilometers. This shift in population caused enormous pressures on shelters and infrastructure services. Urban planning schemes were not able to cope with settlements that rapidly appeared wherever land was available. This haphazard development has had an effect on the environment as the heavy rain drops triggered flooding in the low-lying areas because of the city and its unusual topography. The drainage system was not able to drain down the rainfall as quickly as possible to prevent flooding. The popular experience was that the surplus rain water caused big jams in the region, flooding some areas and damage to public and private property in some parts of the city.

The research hypotheses are,

H0: there is no linkage of managing disaster reduction and adaptation methods for developing and enforcing effective flood management policies and the flood eradication program [Null hypothesis].

H1: there is no linkage of managing disaster reduction and adaptation methods for developing and enforcing effective flood management policies and the flood eradication program [Alternative hypothesis].

Chapter 2: LITERATURE REVIEW

2.1 Introduction

Fluxes can be said to be one of the most frequent and destructive human-life and economic disasters in the world. It may be dated back to Noah's time in history. Floods occur naturally but pose a risk by exceeding the ability and loss of life and property of the affected communities. In the future, the possibility of floods does not seem to diminish and, with the recent incidence of climate change, may threaten many areas of the world with flood intensity and frequency (Ouma and Tateishi, 2014) A flood is defined as the overflowing or irruption of a large body of water over a build-up area, which is not typically submerged. Inland or tides overflow, or unusual and rapid accumulation or rush "(Jeb and Aggarwal, 2008), is a generally temporary condition of partial or total inundation of normally secure areas. Around 15 % to 20% of the precipitation typically ends in rivers as rushing. Through evaporation and transpiation from plants, the rest of the rainfall water soaks up or returns to the ground (Plummer and McGeary, 1993). Rainfall flushes range 2-25% with climatic, raising and slope, soil and rock forms, infrastructure and vegetation variations. Due to the steady and pretty steady precipitation, land and climate can saturate, leading to flooding as runoff is near 100% precipitation (Plummer and McGeary, 1993). A crucial aspect of flood risk management is the visualization of flood risk. It also assists in flood risk assessment and management (Cunningham & Cunningham, 2011). The analysis and understanding of flood risk needs information about the different types and causes of floods and their socio-economic impacts and consequences, likelihood of flood risk occurring, modelling and forecasting, the related mapping data and possible data sources for these disasters (Jha et al. 2012). Also critical in the implementation of effective flood risk / minder assessment steps such as infrastructure planning, emergency services, forecasts / predictions and premature action is a fairly comprehensive knowledge and understanding of flood risk applicable to different communities (Cunningham & Cunningham, 2011). There are major challenges yet to be totally addressed with regard to environmental problems, which are broadly covered by floods (Adeoye, Ayanlade & Babatimehin, 2009). This chapter will review current literature on the worldwide use of the remote sensing and geographical information systems and, in particular, Ghana. It will also analyse the forms, causes and socio-economic impacts and effects of floods and flood mitigation techniques.

2.2 Floods

Floods occur from the rapid accumulation and release of downstream runoff, which is a result of very heavy precipitation. Discharges reach a maximum quickly and decrease nearly quickly (Ouma and Tateishi, 2014). The flow of a stream is also causing floods to surpass its channel capacity, and overflows its banks (Cunningham and Cunningham, 2011). A flood may simply be defined as flooding water into dry land typically. Flooding is primarily due to heavy precipitation; but flooding can occur indirectly with current weather conditions in different ways. A detailed flood clarification will also include activities which are not explicitly related to weather conditions (Doswell 2007). The floods claim around 20,000 lives and have adverse effects in one way or another on at least 20 million people worldwide, particularly those without homes (Smith, 2004). Flooding is one of the most common environmental disasters in the world after epidemics and transportation accidents (Adeoye, Ayanlade & Babatimehin, 2009). The spatial distribution of river flatlands and coasts is responsible for this and its long-standing human settlement attractions (Smith 2004).

2.3 Flooding in Global Perspective

The most devastating floods occurred in the world in 2004 in Haiti, an island nation of the Caribbean, according to the Centre for Research on Epidemiological Disasters (CRED) based in Belgium (CRED 2011). The report also claimed that there were steady and heavy rains for 14 days that caused rivers to swell and subsequently. River banks are largely overflowing in the southeastern parts of the border areas of the Dominican Republic. The Guardian Newspaper reports that the on-going rain caused floods which killed more than 2,400 people (CRED, 2011). As the world's second largest flood in the decade from 2001 to August, the floods that destroyed at least 1,200 lives have already been reported in Pakistan. "To a natural event such as a flux, which is easier to predict and plan for, the number of people who have been killed is very significant," said Debarati Guha-Sapir, CRED director. The monsoon rains caused 2005 floods in India (CRED, 2011). The floods caused around 1,000 deaths and put the disaster second after the flooding in Pakistan. The monsoon rains in the region usually last until September and the assistance workers feared that deaths could increase every year due to flood events. One third of Pakistan is particularly underwater (an area nears the size of England) (CRED, 2011). Seven of the 11 most acute CRED-listed floods occurred in India from 2000 to 2009 for the decade (CRED, 2011). Guha-Sapir notes that the high concentration of the relatively poor rural population living along and within walks of the river banks has put countries like India, Pakistan, and Bangladesh at the top of the lists of lives affected by floods. Over the years from 1996 to 2005, the floods on the continent of Africa were devastating (Satterthwaite et al., 2007). Around 290 floods have been recorded across the continent of Africa over the period of seven years (Cunningham & Cunningham, 2011). About 8 183 people have been reported to have died, 23 million have been affected and economic losses worth around $1.9 billion have been reported (Satterthwaite et al. 2007). In Sub-Saharan Africa, various media and aid organizations have reported a large number of flooding impacts. The floods mostly result from fluctuations that occurred during several and on-going precipitation days (Paeth et al., 2010). For example, Mozambique is consistently affected almost annually by floods, and losses of millions of dollars have been recorded in 2000 (ADB, 2007). Around 800 lives have been lost and a community-based early warning system is therefore required. In Mozambique during the annual flood season, these early warning systems in the Community greatly decreased the number of people missing and killed (Wisner 1979; ADB 2007). In 2013, the Ghana Nachrichtenagentur (GNA) recorded the incidence of flooding that resulted in the loss of a minimum number of 39 human lives in Central Nigeria. Similar reports show that torrential rain has paralyzed most of the Philippine capital, Manila. In the West African region, Nigeria reported some of the highest numbers of deaths (Adedeji, Odufuwa & Adebayo, 2012). The whole villages and agricultural land have been devastated by floods in the northern parts of the country (ARB, 2010). In Ghana, flooding has become an annual threat. In order to save lives and properties, experts are working on ways and means to prevent floods. During the last decade, floods have taken several lives and damaged public buildings and infrastructure (Sam Jr, 2009). Ghana is one of the African countries most exposed to the risk of several climate dangers, including natural risks such as floods and droughts (UNDP / NADMO, 2009) Ghana is one of the most important Due to the concentration of properties and persons in relative small areas and hazardous construction methods the potential for flutter damage is high in urban areas. Urban floods can be defined simply as a natural process, during which the drainage system flows into its floodplain. Ghana is generally caused by urban floods and is in some ways very much linked (Sam Jr, 2009).The Bagre Dam waters in Burkina Faso contribute to farm irrigation during the dry season and recharge the Akosombo dam to a minimum level. However, the dam overflowed with heavy rainfall in 2007. As a result, water from the dam flooded into the White Volta River, which flooded into Ghana with a flood force of 900 m3 per second (Chang, Shahneela, Khatoon & Ali Shah, 2013). The flood has affected the nation as a whole and especially the northern regions (Karley, 2009). Throughout the flood, homes, water and drainage systems were damaged, bridges were sunk. Schools, roads and crops and livestock were damaged. There were numerous families moved. In the school buildings and churches the displaced families found refuge (Forkuo, 2010). However, the floods have also added health implications, especially the danger of an epidemic outbreak. Adequate food and other forms of assistance to the flood victims were found rather difficult by the National Organization for Disaster Management (NADMO, 2007). The latest flood in Ghana has been found to have strong and steady precipitation. Human activities including damming and opening of dam doors as well as dumping of soil to obstruct water flow have increased this situation (Karley 2009). This situation is especially bad. In July 1995, flood damage to lives, properties and public utilities such as water sources, telecommunications, electric power, roads and railway lines were damaged during the Accra flood incidence (Songsore et al . 2006). In this storm, 17 lives were reported, while business and industrial activities were disrupted. In the flood-plain of the rivers Odaw and Onyasia (Songsore et al., 2006), these areas were the most affected.

The landscape, generally on delivered by smooth, steep climbing areas and valleys, was observed in the Kumasi metropole. In 2013, many deaths due to the flood in May-June (NADMO, 2014) were recorded by the metropolis. The Ahinsan Estate, Anwomaso, Oforikrom New Site, Aboabo and Asuoyeboah were the most frequently affected areas. They are rapidly growing urban areas and human activities, such as waste dumping in drains and building in floodplains, which often obstruct the natural inundation plains (Crichton, 1999). The highly affected areas have been described as relatively low lie-out zones and, thus, have mostly valley-like ecosystems, causing heavy or continued rainfall runoffs upstream to downstream (NADMO, 2014). In some villages, such as Aboabo, Atonsu S- Line, Susuanso and Suame, structures and buildings have been built very close to rivers / streams or have blocked the stream / rivers network. In case of precipitation, the upstream rain is collected and its capacity causing the floods easily overflows. In 2013, Asuoyeboah caused two girls to lose their lives (NADMO, 2014). The low-lying areas are mainly susceptible of severe annual flooding in the study area (Aboabo Community) over the last ten years. This is generally due to weak and insufficient drains and taps. In fact, in the City, there is the prevalence of silt that covers and blows down large drains. The annual flooding is primarily due to the fact that streams cannot cope with the surface runoff from continuous rises in paved surfaces, but lack of drainage maintenance and solid waste disposal in the stream often lead to the flooding (Duncan, 2000). Flooding in low-lying or lowland areas is prevalent because water flows in these areas. In these lowly lying areas and significantly along streams and the Aboabo River, Aboabo has various areas affected by the annual flood. This happens when the amount of water due to flux build-ups increases dramatically because of heavy rainfall during rainy season in the communities (NADMO, 2014). The amount of surface water runoff in Aboabo has been gradually rising in the last ten years. The rapid increase in residential, business, infrastructure and urban development is responsible for this development. A few years ago, a large amount of road works contributed to a surface exhaust. In some areas of the community, which had not known such problems in the past, there was an increased incidence of floods and erosion (NADMO 2014).

2.4 Urbanization

There is a trend towards the increasing rise in the number of people moving from rural to urban areas. The need to construct buildings and infrastructure for housing and other operations grows as urbanization grows. Influx risk has increased, especially when the infrastructure, low quality housing and the resilience of urban poor are poorly or insufficiently maintained (World Bank 2008). The risk of flooding has increased. In some instances, buildings and facilities have been built near streams and Primary irrigation plants. Subsequently, these drainage channels were unable to cope with the high amount of runoff water during the storm, which is mostly thick sludge (Sam Jr, 2009). The Aboabo drainage systems were negatively affected by the rapidly rising rate of settlement in this region. Because of negligence and the complete disregard of building codes, many builders face erosion and floods in dangerous ways. The imperviousness of the catchment area is improved by paved roads and by constructing these buildings / houses. Increased river runoff is easily achieved in the catchment areas (A MMA, 2014)

2.5 Types of flooding

Fluvial (River) flooding

A fluvial, or river flood is the situation when the issue of flood has been there for the water level which is high in a river and lake or stream rises where the overflows onto the surrounding bank, neighbour land and shores cause the issue of flood. The water level can be raised due to snowmelt or excessive rain in the locality (Adedeji & Salami, 2011). For analysing the causes of flood, it is mandatory to conduct in depth analysis on past precipitation, forecasted precipitation, current river levels, and well as soil and terrain conditions (ActionAid, 2006). The danger of river flood can cause higher impacts as compared to the smaller river downstream flood. In this regard the intensity and duration of the rainfall is mandatory to be analysed for analysing the river flood and there are also other factors through which it is possible to determine the reasons of causes which includes soil water saturation for the previous rain fall and the terraion surrounding the river system (Brivio et al., 2002). Hereby, rainfall is the major causes of river flood and it can damage the surrounded areas of the locality (Arheimer and Brandt, 1998).

Pluvial (surface) flooding

The pluvial flood is related to the situation when flood occurs due to extreme rainfall for over floating of the water body in the locality (Arheimer and Brandt, 1998). It is a misconception among the societies that flood is the serious issue for the individual who live near water body and this it can be stated that, pluvial flood can happen in any location urban and rural and even in the locations with no water bodies in the vicinity (ArcGIS Resources, 2012). Two types of pluvial flooding are Surface water floods and Flash floods. The Surface water floods occurs when an urban drainage system is overwhelmed and water flows into the nearby areas and streets and it further provides a time to the individuals in the localities to shift to a safer place. For the people with poor economic condition, there are serious impacts of Surface water floods (Arheimer and Brandt, 1998). On the other hand, Flash flood is characterised by the factors such as nearby elevated terrain and high velocity torrent of water triggered by the torrential rain falling in a short period of time. There is huge volume of forced water in this type of flood and it is dangerous for the individuals and on the other hand it also raises the issue of hurtling debris that is often swept up in the flow (ArcGIS Resources, 2012).

Coastal (surge) flooding

Coastal flooding causes due to intense windstorm events occurring at the sales time as high tide storm surge and tsunamis. The coastal regions are highly affected for such Coastal flooding. Storm surge is created when high winds from windstorm force water onshore and it leads to the cause of coastal flooding with serious threats associated with the windstorm (ArcGIS Resources, 2012). The effects of coastal flooding are increasing during the high tide results in devastating storm surge floods. There is water overwhelms low-lying land and often it causes devastating loss of life and property in the coastal areas and also surrounded localities (Bertilsson & Widenfalk, 2002). There are also several factors that must be analysed for evaluating coastal flooding and the factors are such as size, speed, strength and direction of windstorm. The onshore and offshore topography is also another important factor for evaluating the situation of coastal flood and it is helpful to determine the probability and magnitude of a storm surge, coastal flood through managing historical data and calculations of the chance of coastal flooding (Bertilsson & Widenfalk, 2002).

Co-incident flooding

The coincidence of flood may lead to the situation of catastrophic floods and there are serious risk factors of the co-incident floods under the non-stationary conditions arising from climate changes (ArcGIS Resources, 2012). The occurrence of dates and flood magnitude can be measured by the researchers in weather condition on stationary multivariate models and compared with those from stationary models as it depends on the climate change (Blomqvist, 2003). In this particular study, The Huai River and Hong River were selected which causes flooded in the flood prone areas and also hamper the localities beside the areas (Cunningham & Cunningham, 2011). The marginal distributions for the flood magnitudes can also be measured with the time-varying copulas and there is annual probability of coincident flooding in the areas with serious risk factors and hence it is essential to analyse no stationary models in climate change scenarios (Aziz, Tripathi, Ole, & Kusanagi, 2002).

Groundwater flooding

Groundwater flooding is caused when the water table rises up from rocks or soils to above ground level, causing flooding to occur at the surface. This tends to occur after season-long periods of high rainfall (Aziz, Tripathi, Ole, & Kusanagi, 2002). The rainfall infiltrates into the ground causing the water table to rise in response above normal levels (Cunningham & Cunningham, 2011).

Flooding due to asset performance

Flooding is a major risk for the loss of life and economic damage mainly in the North Sea Region. There are several flood protection infrastructure, that includes dykes, sluices and dams are ageing (many are 70-100y old) and often their performance is hampered as it is no longer at the desired level, adaptation, requiring renovation, and maintenance all across the region (Burrough, 1986). The objective of the FAIR project is to reduce flood risk across the North Sea Region by evaluating climate change adaptation solutions for improving the performance of flood protection infrastructure. FAIR is considered as improved approaches with cost-effective upgrading and maintenance, further optimising the investments across the national-system-asset levels, as well as applying adaptive and innovative technical designs (Burrough, 1986).

2.6 Future changes

Deviations in Rainfall intensity, distribution

The practice of urbanization and urban creep

Effects of asset deterioration and renewal

Introduction of emerging and new technologies

Variations in Groundwater level and Infiltration

Fluctuations in local flood pathways and urban form

2.7 Urban Flooding

Unplanned urbanization

An significant expansion of the urban areas

Increases in the built-up areas and metal roads

Filling of low-lying areas to construct buildings

Construction of insufficient storm sewers

Lack of maintenance and co-ordination

Dynamic weather patterns due to Climate Change Urban Flooding

55% of India’s population would be in urban areas by 2030 and go up to 65 – 70% by 2050

All future growth would be in towns and cities in Asia and urban population would double between 2000 and 2030

Census 2001 figured 285 million people in 35 metro cities of India, and it is further estimated to cross 600 million with 100 metro cities in 2021

2.8 Components of urban flood model

2.9 Urban Flood Studies in India

Chennai - (Anna University + PWD +US Agencies)

Hyderabad - (GHMC+NDMA+US Agencies)

Urban Flood Disaster Management

Bangalore- (NRSC + IISc)

Urban Flood study was taken up in collaboration with IISc, Bangalore Urban Flood Studies in India

Early warning system installed for mitigating urban flooding.

30 AWS with tipping bucket rain gauges (average density 1 in 10 km2) in each grid fire station; manned 24 hrs.

Data transmitted to Emergency Operations Centre (EOC) in the MCGM headquarters every 15 minutes through LAN.

Rain gauges have been calibrated to give alarm at predefined values of rainfall intensity (40 mm/h)

2.10 Understanding the problem

Flood mechanisms and interactions between different urban drainage systems

Scale of the flooding (e.g. localized, town‐wide or river catchment wide)

Frequency of the flooding;

Consequence of the flooding (e.g. degree of nuisance, cost)

Basis of modelling is an extremely accurate urban surface DEM/DTM

2.11 Floods in Hyderabad

There are several impacts of climate change causing extreme weather events and the causes are such as bad planning, preparedness, encroachment of lakes and poor urban infrastructure which cause flooding in the locality. Hyderabad lost 33 lives, nearly 40,000 families got badly impacted and suffered a property loss of Rs. 6.7 billion (Rs 670 crores) as per official estimates. For the residents in Hyderabad city, India, September moth is usually considered as a month of heavy rainfalls and the Great Musi Floods of 1908 is the famous incident in the city that hampers the livelihood of the individuals caused by the unprecedented downpour on September 28 and hence, September is considered as a high concerned moth of the year (Black, 1996). In October 13-14, there are serious weather changes and the people face the issues of flood due to cloud bursts and flash floods over a week as well as sudden spells of heavy downpour. Researchers explore that the issue of flooding in the locality is due to the fragile and inefficient urban infrastructure of the capital of Telangana. Hyderabad witnessed a record rainfall in 24 hours and Hyderabad of October 2020, Chennai of December 2015 and Mumbai of July 2005 are definite cases of extreme events. It is hereby a high time for the population to call urban planners to firm up the strategies and implement flood management policies to minimise the damages of such events in the city, whose occurrence could only increase in future, say experts. Annual average fatalities in India due to climate hazards are about 3660, which is the second highest in the world and the major issue of India is the vulnerability of southern cities to urban flooding. Extreme rainfall events occurred in Hyderabad in 2016, 2010 and 2000 as well as Kerala was swamped by floods in 2018 and Chennai battered in 2015. According to a recent study by the Centre for Earth, Ocean and Atmospheric Sciences of the University of Hyderabad (UoH), there are critical causes of the situation of flooding which are such as increasing urbanisation in Telangana and Tamil Nadu that is likely to enhance the rainfall during heavy rainfall events by 20- 25%. The study by Karumuri Ashok and Boyaj of UoH has been done in collaboration with Ibrahim Hoteit and Hari Prasad Dasari of the King Abdullah University of Science and Technology (KAUST), Saudi Arabia. The research utilised Land Use Land Cover (LULC) imagery from the Indian Space Research Organization (ISRO) and conducted a dozen simulated, and it has been evidenced that heavy rainfall events over the three southern states. The changes in LULC led to higher surface temperatures and a deeper and moist boundary layer and it further caused a relatively higher convective available potential energy and, consequently, heavier rainfall. Incidentally, Hyderabad celebrated its 429th foundation day on October 7-8. Even before the celebrations in such pandemic era, dark, rain-bearing clouds converged over the city for of a cyclone in the Bay of Bengal. Consequently, on October 13-14, the tri-city — Hyderabad, Secunderabad and Cyberabad — an extent of 650 sq km, got battered with an all-time record rainfall of 29.8 cms in 24 hours. The findings also were reported in the ‘Quarterly Journal of Royal Meteorological Society’ on May 18, 2020. The August 2000 downpour was recorded at 24 cm. For the record, the single-day highest rainfall record in the state of Telangana is 35.5 cms in October 1983 in Nizamabad. The precipitation levels during heavy rainfall events have significantly increased from 2000 to 2017. According to B. Raja Rao, of India Meteorological Department (IMD), Hyderabad, “The unusually heavy rainfall was due to two reasons. The deep depression in the Bay of Bengal moved onto the land in Hyderabad. The second was the rain bearing clouds of the withdrawing Southwest monsoon also pouring out.” People in large parts in Hyderabad woke up to water everywhere and many lives thrown out of gear. Several low lying localities were deluged in the water from rains and overflowing water bodies.

In the local and global level, increasing population has its impacts on maintaining water level and urbanisation is one of the major causes of such climate change leading to the transition of a natural catchment into an urbanised catchment results in many environmental impacts. According to Elga et al. urban development is considered as a major source of pollution for water resources, and it leads to increasing flooding and threatening to the livelihood of the individuals across the societies, mainly in the flood prone area. Du et al. found that, urbanization reduces infiltration, base flow and lag times, as well as increasing peak discharge, storm water flow volumes, frequency of floods and surface runoff which also leads to climate change and critical environmental impacts. The severity of all these hydrological impacts is dependents to the urbanisation activities across the countries. Hence, the impacts of urbanisation on the environment is crucial, where in particular hydrological processes like flooding of a catchment, need to be quantified for setting the limitations on levels of permissible urban development [4]. Hydrological modelling is effective to use change model on hydrological responses and it is helpful to identify he areas of interest that has crucial impacts on land use changes and flow regimes. Mao and Cherkauer used Storm Water Management Model (SWMM) to study land use change responses in the upper Midwestern United States and as per the study, deforestation increased runoff by 30% to 40% in the central part of the country. The Hydrologic Engineering Centre’s Hydrologic Modelling System (HEC-HMS) and the integrated Markov Chain and Cellular Automata model (CA-Markov model) are also utilised to investigate runoff from land use changes in the USA and it has been concluded that, when impervious ratios changed from 3% to 31%, daily peak discharge increased from 2.3% to 13.9%. South Australia is the driest state in the Australian continent and the Myponga catchment is located in south of the South Australian capital, Adelaide. Urbanization in South Australia has been increasing during the last few decades and there are many catchments that are being transformed from natural to urbanize. The Myponga catchment, in particular, has experienced significant land use change during the recent years. Wella-Hewage [8] further reported that, 75% of the Myponga catchment area was used for cattle and sheep grazing in 2002, but this has been decreased to 69% in 2014. The residential use increased from 4% to 24% during the same period. These land use changes have increased the risks of flooding in the vicinity of Myponga Reservoir. The effects of land use also change needs that to be examined in order to sustainable development, thus minimising the impacts on humans and water resources. SWMM is considered as an effective tool for modelling the hydrological processes of a catchment. SWMM was first developed in 1971 in the USA by the Environmental Protection Agency (US EPA) and the latest version if SWMM 5 where the system is widely used across the global regions for dynamic rainfall runoff and it is utilised both in urban and rural catchments. SWMM is utilised for further planning, designing, analysis and management related to combined sewers, sanitary sewers, storm water quantity, and other drainage systems in the urban areas and it is also efficiency for rural catchments in water quality modelling. SWMM is a catchment scale model that provides an integrated environment to edit input data for a given study area. Several studies have utilized SWMM, including Lee [3], Sun, Hall, Hong and Zhang [11], Wella-Hewage [8], Abdul-Aziz and Al-Amin [12] and Yu et al. [13], for low flow studies, catchment discretization, Water Sensitive Urban Design (WSUD) methodology development, runoff and pollutant modelling and drainage system analysis, respectively. A commercially available advanced model PCSWMM is effective for further analysis and it was developed in 1984 with a Geographic Information System (GIS) linkage to provide a comprehensive range of applications (Blomqvist, 2003). PCSWMM is a combination of GIS and US EPA SWMM 5, which provides a scalable and complete package for 1D and 2D analysis of rainfall runoff processes (Blomqvist, 2003). PCSWMM has Comprehensive River modelling tools, time series management, Digital Elevation Model (DEM) support, real-time control analysis, native GIS support; hydraulics automated reporting and Google Earth visualization for hydrology and water quality modelling. PCSWMM also has the ability to further model the storm water source control technologies to maintain and analyse water quantity and quality [9]. Storm water source control techniques are referred to as WSUD in Australia, Low Impact Development (LID) in the US, Sustainable Drainage Systems (SuDS) in the UK and Low Impact Urban Design and Development (LIUDD) in New Zealand. Hence, PCSWMM has been adopted for this research to investigate the effects of urbanization on the hydrological responses of the Myponga catchment. Additionally, WSUD technologies were also investigated for determining whether it is possible to minimise the impacts in relation to flood control and water management.

2.12 Flash floods in Hyderabad

In August 2000, the town of Hyderabad suffered unprecedented inundation, which caused massive property damage and some human loss. The town of Hyderabad with a population of about 3.82 million inhabitants (2001 census) was spread over 55sq.km in September 1908; August 2000 and August 2008 with severe flooding. In table 2 below are presented the loss of property and loss of life and numbers of people affected by those floods. Hyderabad’s maximum water drainage capacity is 12 mm / hour. Unauthorized invasions of the river beds closed down drains and river banks that block naturally existing drains further limit the potential for urban storm water runoff.

2.13 Statistics related to floods in Hyderabad

The Musi River caused the destruction of the city of Hyderabad on several occasions. History Records that since 1572AD, Hyderabad has been flooding 11 times. On September 28, 1908, the city experienced a precipitation of 15.32 cms. 15,000 people have been killed; more than 80,000 have been made homeless, according to historians. The fury of the river affected as many as 600,000 people Year wise record of heavy rainfall events are given below:

A recorded precipitation of 190.5 mms on August 1, 1974

The precipitation recorded was 140 mm in 1997.

Recorded precipitation in just 24 hours on 24 Aug 2010. In August the cumulative precipitation was 469 mm and the city’s greatest calamity in nearly 50 years washed away several sections of the roads with 90 residential zones (in some cases less than 10-15 feet) under the water in the city.

Reported precipitation of 230.4 mm in August 2011.

Recorded precipitation of 179.4 mm in August 2012.

Reports of precipitation of 218.7 mm in 2016.

Reported precipitation of 220,7 mm in 36 hours in August 2018

2.14 Successful implementation of the Flood Management Techniques will enable:

Enable the definition in the GHMC Community of hot spot flood areas.

Have realistic and cost-effective ways to develop and assess the effects on planners and emergency management agencies to identify flood plains and other vulnerable areas.

Provide basic land use planning information. Enable new urban development plans.

Allow adequate assessment of flood costs and the benefits of flood reduction.

Show areas that are more vulnerable to flooding because it is easier to ensure that evacuation or preparation plans are well and easily developed.

The insurance policies are to be used as foundation.

The insurance policies are to be used as foundation.

Have a general planning guide on where and how to build.

It is also intended to act as a basic guide to flood control stakeholders

PCSWMM model

HEC-RAS Model

Hand Model

MIKE Model

Chapter 3: METHODOLOGY

3.1 Flood Modelling for Hyderabad

Objective:

To develop combine 1-D and 2-D flood inundation model for a storm water zones/ catchment zone in Hyderabad.

Data Required:

Hydrological data- Rainfall Topographic data– DEM Existing storm water drain map, Details of lakes, GHMC Storm master plan, Survey details of drain, water bodies, Details of culverts in various zones. Vector data such as Catchment Boundary, Drainage centre line, Building layers etc.

Models:

PCSWMM, Mike Urban

Study Area

Hyderabad is divided into 16 storm water zones /catchment zones by GHMC. Among the storm water zones, zone12 Kukatpally & zone13 Alwal and Begumpet area are major flood prone areas.

3.2 Pilot Study

Carried out for part of a stream of 12 km which starts from Foxsagar Lake to Hussainsagar Lake of catchment zone 12 of Hyderabad.

The Stream passes through the major floodplain areas like Quthbullapur, Venkanna Hills and Manikya Nagar.

The cumulative rainfall was experienced 165mm at Quthbullapur on 21/09/2016 and same was used as input.

The flow into the Hussain sagar was 4000 cusecs and the authorities let out 2500 cusecs. The FTL was 513.4 meters was achieved.

3.3 Research method

The data collection and analysis are essential for conducting the research and developing systematic way to complete by meeting the above mentioned research objectives. For data collection method, the researcher focuses on gathering secondary sources of information by reviewing the books, journals and articles related to the above mentioned research topic. Additionally, for data analysis, qualitative data analysis is being chosen to analyse the gathered data with in-depth evaluation and critical discussion. Hence, the data collection and analysis is effective to conduct the study in a systematic way for meeting the research aim and objectives.

4. MODELLING AND DISCUSSIONS

4.1 PCSWMM model

PCSWMM model is an integrated urban drainage system that is effective for reducing the effects of climate change and it is beneficial for storm water management, waste water and watershed modelling (Santoro et al., 2019). It is also advantageous for single event or long-term (continuous) simulation of runoff quantity and quality, primarily for urban areas, where the components operates on the collection of the sub catchment areas which receive the recitation and generate run off and pollutant loads (Richert, Erdlenbruch & Grelot, 2019). On the other hand, it is effective for routine portion transports that in off through the system of channels, storage or treatment devices, pumps, regulators and the system of pipes. It is hereby beneficial for tracking the quantity and quality of runoff generated in each catchments and the flow rate, water quality and flow depth are managed through the pipe and channel during a simulation period. In PCSWMM, the rainfall runoff process is conceptualized by using the material and water flow between its environmental sectors. The system is managed through four components which are ground water compartment, atmospheric compartment, transport compartment and land surface compartment.

Catchment weighted average rainfall for the Myponga catchment has been computed by using the Thiessen Polygon method. Although the measured flow data at gauge station A5020502 were available from 1980 to 2014 and on the other hand, rainfall data were not available for all 35 years as some rain gauges were removed or relocated (Richert, Erdlenbruch & Grelot, 2019). Therefore, the period between 2005 and 2014 was adopted for model calibration (2005–2010) and validation (2011–2014) purposes. However, soil types and water table levels were gathered from DEWNR [7] and Barnett and Rix [16] and the remaining parameters were arranged through model calibration using default initial values (Abebe et al., 2019). Hydrologic and land use data are utilised for land surface components that are extracted from a GIS database obtained from DEWNR. The catchment delineation tool from PCSWMM is hereby beneficial for further catchment delineation from DEM data and then discretized into sub-catchments. Finally, 28 sub-catchments were created with conduits and junctions, while the reservoir was treated as an outfall. The impervious percentage for each sub-catchment has been calculated by using sub-catchment layers and land use layers through catchment conceptualization (Mall et al., 2019).

4.2 Methodology of Combined 1D & 2D PCSWMM model

4.3 HEC-RAS model

HEC-RAS is a computer program that is useful for modelling the water flow through the natural rivers and other channels. Prior to the 2016 update to Version 5.0, the program was one-dimensional, which indicates that there was no such direct modelling of the hydraulic aspects of the flow (Mercado, Kawamura & Amaguchi, 2020). Version 5.0 has been introduced for two-dimensional modelling of flow as well as sediment transfer modelling capabilities (Norizan, Hassan & Yusoff, 2021). The program has been developed by the United States Army Corps of Engineers with the aim of managing the harbours, rivers and other public works under their jurisdiction (Tyler, Sadiq & Noonan, 2019). The Hydrologic Engineering Centre (HEC) in Davis, California, developed the River Analysis System (RAS) for aiding hydraulic engineers in channel flow analysis and floodplain determination (Mohanty, Mudgil & Karmakar, 2020). It further includes hydraulic analysis components, numerous data entry capabilities, data storage and management capabilities, as well as graphing and reporting capabilities. It is hereby beneficial for modelling the water flowing system with open channels and computing water surface profiles (de Ruig et al., 2020). HEC-RAS is considered as floodplain management and [flood insurance] studies for evaluating the floodway encroachments. The other studies such as levee studies, bridge and culvert design and analysis and channel modification studies are also effective for successful flood management (Gussmann & Hinkel, 2021).

4.4 Inflow Hydrograph

The Output results of HEC-HMS in the form of Discharge Hydrograph given below are the input for HEC-RAS Model. X axis shows time and y axis shows Discharge in Cumecs.

Analysis system (HEC-RAS) developed by the Hydrological Engineering Centre. Using this program, one-dimensional constant flow calculations, unstable flow calculations, transport sediment / mobile beds and water temp modelling are possible. During unstable tests, users can find numerical problems of instability, in particular in steep rivers and streams with high dynamics. HEC-RAS can also be used to solve river instability issues. HEC-RAS is a 1-dimensional hydrodynamic model, which does not function well in multi-dimensional modelling environments. However, apps can be used for approximation in hydraulics of many dimensions. HEC-RAS has been designed to be collaborative for a variety of tasks and integrated software systems. A GUI, independent analytical components, data storage and management, graphics and reporting equipment are provided. The HEC-RAS software comprises four single-dimensional river analysis elements. [1]:

Calculation of smooth water flow surface profile

Calculation of moving boundary sediment movement

Study of water quality.

The growing reproduction of geometric data and routines for geometric and hydraulic computation in all three components are a key feature. The system also has several hydraulic design features that are ideal for use in basic water surface profiles after calculating the water level. [1]

4.5 Identification of low lying areas of Hyderabad by HAND model

HAND is Height above Nearest Drain Model that normalizes DEM.

The HAND model normalizes topography according to the local relative heights found along the drainage network.

Low lying areas are identified for Hyderabad

4.6 Methodology

4.7 Hand Model

HAND model normalizes the topography in respect to the drainage network

A hydrological coherent DEM is created

Flow paths are defined and drainage channels are delineated

Elevations of the drainage channel system are used to calculate the normalized terrain heights.

4.8 HAND Classes

A HAND terrain class is defined as a range of vertical distances to the nearest drainage reference level that bears roughly uniform hydrological relevance

The HAND classes were defined in order to know the water logged area within a catchment

HAND 1m and 2m classes is designated as High vulnerable and Low vulnerable

4.9 Low Lying areas in GHMC region

4.10 MIKE Model

Hybrid Approach in which 2D for the overland flow & 1D for rivers/channels & for storm water drainage in piped underground networks are used.

Classical one dimensional model is poor tools for flood analysis in urban area (Ravazzani et.al., 2006) and requires a coupled approach (Schubert et.al., 2008).

MIKE 21 Flow Model is an effective modelling system for the 2D free-surface flows. MIKE

21 Flow Model is mainly an applicable that simulates the hydraulic and environmental phenomena in lakes, estuaries, bays, coastal areas and seas. It may be applied wherever stratification can be neglected.

The hydrodynamic (HD) module is the basic module in the MIKE 21 Flow model

It provides the hydrodynamic basis for the computations performed in the Environmental Hydraulics modules.

The hydrodynamic module simulates water level variations that flow in response to a variety of forcing functions in estuaries, lakes and coastal regions. The effects and facilities include:

Flooding and drying

Bottom shear stress

Carioles force

Barometric pressure gradients

Momentum dispersion

Wind shear stress

Sources and sinks

Wave radiation stresses

Evaporation

MIKE 21 Flow Model, Hydrodynamic Module, can be applied to a wide range of hydraulic and related phenomena. This includes:

Modelling of tidal hydraulics

Wind and wave generated currents

Storm surges

As mentioned previously, the MIKE 21 HD output results are also utilised as an input for many of the other MIKE 21 modules including the Sediment Transport (ST, MT), the Particle tracking (PA), the Advection-Dispersion module (AD) and the Environment module (MIKE ECO Lab). As MIKE 21 HD is a very general hydraulic model, it can easily be set up to describe specific hydraulic phenomena. Examples of such applications are secondary circulations, eddies and vortices

Harbour searching

Dam-break

Tsunamis

4.11 MIKE URBAN

Data preparation of DWR data from IMD and ingesting into the model

Collection of data for Hyderabad from GHMC like Existing storm water drain details, Survey details of drain, Details of lakes/water bodies, culverts in various zones., GHMC Storm master plan and Discharge data of stream /Nalas

Calibration and Validation of the model

4.12 Urban Flood Management

4.13 Urban Flood Management Cycle

Warning Dissemination

Data transmission

Model for processing

Scenario generation

Database creation

AWS network operation

Resources Planning

Land use planning

Restrictions on uncontrolled development

Preserving natural drainage

Proper Maintenance of surface & underground drainage

Public awareness

Alert

Relief & Rescue

Information / Instructions Dissemination

Resource mobilization

Facilities restoration

Event analysis

4.14 Need for integrated urban drainage within an integrated catchment

What Can Homeowners Do

Households can develop alternatives to areas traditionally covered by imperious surfaces in order to decrease the amount of runoff from paved surfaces. For entrances and sidewalks porous pavements are available, and high-maintaining grass lawns are replaced by local vegetation and mulch. Rather of using tubing, owners should sparingly use fertilizers and brush parks, sidewalks and highways. They must also take measures to conserve water to extend the life of their septic systems.

New Architecture Effects Monitoring

The implementation of low impact, structural controls and pollution reduction strategy will aim to monitor the amount of runoff from new construction by emerging and municipal designers. Substantial impacts include measures to preserve natural areas (especially sensitive areas such as riparian buffers and unfilterable soils), to decrease developmental effects and to reduce site runoff by maximizing surface roughness, possibilities for infiltration, and flow pathways.

Command of current product impacts

Runoffs from existing urban areas are often more expensive than runoffs from new developments. First urban planners may identify and enforce source management incentives, and other responsible for maintaining urban and suburban areas. They should seek priorities for reduction, protect natural areas which help to monitor runoff and finally start ecological restructuring and rehabilitation activities. The public signage, storm drain labelling and collaboration with citizens' associations and companies enable municipal municipalities to play a leading role in public education initiatives.

Engineering Level

Set up a separate drainage network.

Pervious flooring must be placed particularly in areas that do not contain heavy traffic, especially in colony bye paths to minimize surface runoff.

Structures for rainwater collection should be built by GHMC where possible instead of placing personal responsibility.

Policy Level

Although not officially specified, mitigation of floods can be considered to be a variety of measures that affect life and property exposure to floods. The holistic character of these steps is to control floods which have no structural characteristics.

Means of prevention include planning, training, policymaking, collaboration, awareness-raising, assistance and enhancement is known as Mitigation. This also includes education, training, regulation, reporting, prediction, alert and information. Yet compensation, assessment, funding, relief and recovery are not exempt. If systemic interventions are the pillars of a system of flood control, mitigation is its very nature.

Chapter 5: CONCLUSIONS

5.1 Conclusion

The final conclusions were made based on the case studies of Panjagutta and Khairathabad Flood prone areas in Hyderabad

Identification of vulnerable zones in and around the mega cities

Improvement of old drainage systems, reinforcement of weak and old buildings

Implementation of health and sanitation measures

Preparation of a long term plans aimed at diversification of industries

Greater awareness among the public for the weather warning and forecasts.

Pollution control measures with planning of green cities, including urban reforestation.

Integrated Storm water management

Managing freshwater, wastewater, and storm water

Retention Ponds, Onsite Detention (OSD), Rainwater Harvesting, Green Roofs, Pervious Pavements

Better forecasting of heavy rain over cities with the help of Doppler radars

There are high risks in the Panjagutta and Khairathabad Flood prone areas in Hyderabad and as per the study it is important to develop flood management policies and implement effective intervention planning to mitigate the issue of flooding. The NRSC Arc Map- Arc GIS and Arc View GIS software is hereby beneficial to prepare data, integrate and analyse data and it further provides a scope to predict the chance of flooding. The road network, soil type, land use and spatial dataset for land use are important to be analysed for developing flood emergency planning by using spatial dataset. As per the findings, in Panjagutta and Khairathabad in Hyderabad, the soil and water are also affected for such incident of flood and flood emergency response in flood-inundated area by using GIS. The major impacts of flood are on the population, assets and property and environment which are at risk in the flood prone areas. The emergency response department can use GIS to calculate the numbers of residents develop emergency plan for shifting them towards safe area and develop further long term planning to reduce the issue by effective disaster preparedness programs.

5.2 Recommendations

Command centre for flood forecasting is considered as an effective flood mitigation plan with flood impact analysis, estimated loss of environment that can be identified and mitigated up to some extent with the proper use of emergency planning using GIS.

Jointly structural and non-structural measures with use of GIS technology could immensely help flood command centre. Also it provides a scope to different administrative level, engineering agencies, NGO and other agencies to take immediate measures during actual occurrence of flood. Hence, GIS data base should be developed in long run for the decision makers, disaster planners to create immediate intervention planning in case of emergency with the previous data available.

Proper land use planning must be developed in the flood prone areas from evacuating point of view, by prohibiting further encroachment of residential and industrial zones mainly in the high-risk areas, by only allowing the open activities such as setting up of playground or parks.

Integrated drainage system in the Panjagutta and Khairathabad Flood prone areas in Hyderabad is mandatory to be developed to maintain the quantity of water flow and depth of water flow. Around the city Hyderabad, it is necessary for the government and disaster relief organisation to strategize the integrated drainage system to mitigate the issue of flooding.

Flood risk maps helps in Identification of flood hazard zone and preparation of GIS based flood impact maps which would be beneficial to help the authorities for taking quick assessment during occurrence of disaster.

The government must focus on flood rescue system by using the object HEC-RAS for identifying different property or land use at risk and road network data in the flood hazard zone that can be utilised to generate location spatial dataset of different location and routes.

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