Urban Flood Resilience in Himalayas | Dissertation Report | NIT Hamirpur

URBAN FLOOD RESILIENCE IN HIMALAYAS

B. ARCH. DISSERTATION

BY MANISH AGRI (ROLL NO. 16609)

DEPARTMENT OF ARCHITECTURE NATIONAL INSTITUTE OF TECHNOLOGY HAMIRPUR (H.P) – 177005, INDIA JULY, 2020

URBAN FLOOD RESILIENCE IN HIMALAYAS DISSERTATION

Submitted in partial fulfilment of the requirements for the award of degree of BACHELOR OF ARCHITECTURE by

MANISH AGRI (ROLL NO. 16609) Under the guidance of DR. VANDNA SHARMA

DEPARTMENT OF ARCHITECTURE NATIONAL INSTITUTE OF TECHNOLOGY HAMIRPUR (H.P) – 177005, INDIA JULY, 2020

Copyright @ NIT HAMIRPUR (H.P), INDIA, July,2020

NATIONAL INSTITUTE OF TECHNOLOGY HAMIRPUR (H.P) DEPARTMENT OF ARCHITECTURE

CERTIFICATE

This is to certify that that this dissertation report entitles “URBAN FLOOD RESILIENCE IN HIMALAYAS” has been submitted by Mr. Manish Agri (Roll No. 16609) in the partial fulfilment of the requirements for the award of the Bachelor’s degree in Architecture for the session 2016-2021.

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Dissertation guide DEPARTMENT OF ARCHITECTURE DATE:

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DISSERTATION REPORT

(2019-2020)

URBAN FLOOD RESILIENCE IN HIMALAYAS

DISSERTATION GUIDE:

SUBMITTED BY:

DR. VANDNA SHARMA

MANISH AGRI, 16609

NATIONAL INSTITUTE OF TECHNOLOGY HAMIRPUR (HP)

CANDIDATE’S DECLARATION I hereby certify that the work which is presented in the project titled “URBAN FLOOD RESILIENCE IN HIMALAYAS”, in the partial fulfilment of the requirements for the award of the DEGREE OF BACHELOR in ARCHITECTURE and submitted in Department of Architecture, National Institute of Technology, Hamirpur, in an authentic record of my own work carried out during a period from January 2020 to July 2020 under the guidance of DR. VANDNA SHARMA, Assistant Professor-I, Department of Architecture, National Institute of Technology, Hamirpur.

The matter presented in this project report has not been submitted by me for the reward of any other degree of this or any other Institute/University.

MANISH AGRI This is to certify that the above statement made by the candidate is correct to the best of my knowledge.

Date:

DR. VANDNA SHARMA Assistant Professor Department of Architecture NIT Hamirpur

The Project Viva Voce Examination of MANISH AGRI (16609) has been held on………………………

Signature of Supervisor(s)

Signature of External Examiner

ACKNOWLEDGEMENT

On the very beginning of this report, I might want to broaden my earnest and sincere commitment towards all personages who have helped me in this undertaking. Without their dynamic direction, help, collaboration and support, I would not have made progress in the dissertation.

I am exceedingly obliged to my guide, Dr. Vandna Sharma for her direction and steady supervision and in addition for giving vital data with respect to the undertaking and furthermore for her help in finishing the task.

I am amazingly grateful and pay my appreciation to my Head of Department, Dr. I.P. Singh, Dissertation Coordinator Dr. Aniket Sharma and DUGC Dr. Rashmi Kumari for their significant direction and support in finishing of this exploration in its by and by.

I stretch out my appreciation to NIT HAMIRPUR (H.P.) for giving me this opportunity.

I would like to thank Dr. Lakra Harshit Sosan, Assistant Professor, IIT Roorkee for helping me out with GIS, EIA and Expert Systems.

I likewise recognize with a profound feeling of respect, my appreciation towards my folks and individuals from my family, Mr. Prabir Kumar Agri and Mrs. Kamla Agri who have constantly bolstered me ethically and also financially.

Finally, yet not slightest appreciation goes to the greater part of my companions who specifically or in a roundabout way helped me to finish this exploration report.

ABSTRACT

Urban flooding has emerged as a big challenge with emergence of urbanisation and climate change. Predictions in urbanisation and climate indicate that this challenge is going to take severe forms in future. Despite of prior knowledge, our cities have not proved prepared enough to resist this shock. Cities in Himalayas, further lack this resilience due to geographic complexity. The problem is with our insufficiency in assessing disasters, corresponding damages and conventional planning and preparation methods.

The need is to understand the causes of urban flooding, thereafter, devise solutions for their implications in urban designing and planning, using modern technology available to us.

This study attempts to explore the potential of this technology and how it can be used to build flood resilient cities in Himalayas.

TABLE OF CONTENTS List of Figures ………………...………………………………………….…………………...1 List of Tables …………………………………………………………………………………3 Chapter 1- Introduction ………...……………………………………………………..…….4 1.1.

1.2.

1.3.

Aim ………………………………………………………………………….…………4 Objectives …………………………………..………………………………………….4 Scope …………………………………………………………………………………..4

Chapter 2-Understanding Urbanisation in Indian Himalayas ……………………………6 2.1.

2.2.

2.3.

2.4.

2.5.

2.6.

2.7.

Urbanisation in India …………………………………………………………...……...6 Urbanisation in Himalayas ………………………………………………………...…..6 Potential of development in Himalayas …………………………………………….....8 Development pattern in Himalayas ……………………………………………………9 Problems of development in Himalayas …………………………………..................10 Challenges to development in Himalayas ……………………………………………10 Sustainable Development in Himalayas ………………………………………….......10

Chapter 3-Water System in Himalayas ………………………………………....................11 3.1.

3.2.

3.3.

3.4.

3.5.

3.6.

Indian Himalayas …………………………………………………………………….11 Drainage ……………………………………………………………………...............12 Basin Denudation and sedimentation ………………………………………...............13 Precipitation ………………………………………………………………………….13 Relation between elevation and rainfall ……………………………………...............13 Monsoon Floods in Himalayas: Past Present and Future ………………………….....14

Chapter 4- Urban Flooding and Factors ………………………………………..................15 4.1.

4.2.

4.2.1.

4.2.2.

Urban Flooding ………………………………………………………………………15 Factors …………………………………………………………………..……………15 Natural Factors ...…………………………………………………………………......15 Manmade Factors ……….……………………………………………………………18

Chapter 5- Case Study …………………………………………………………...................27 5.1.

5.1.1.

5.2.

5.2.1.

5.3.

Uttarakhand Flash Floods, 2013 ………………………………………………...…...27 Causes ……………………………………………………………………………......27 Dehradun Annual Floods …………………………………………………………….31 Causes ……………………………………………………………………………......31 Key Recommendations/Lessons learnt ………………………………………………33

Chapter 6- Flood Prevention, Preparedness and Mitigation …………………….............35 6.1.

Structural measures ………………………………………………………………......35

6.2.

6.3.

6.4.

Non-Structural measures ……………………………………………………………..37 Regulations/Guidelines/Bylaws ………………….………………………………......39 Environmental Impact Assessment …………………………………...……………...39

Chapter 7- Expert Systems and GIS ………………………………………..……………..41 7.1.

7.2.

7.3.

7.4.

7.5.

Role of Expert Systems ………………………………………………………………41 Fundamentals of Expert Systems ……………………………………...……………..41 Uses of Expert Systems …………..……………………………………......................45 Limitations of Expert Systems ……………………………………………...………..45 GIS …………………………………………………………………………...……....45

Chapter 8- Conclusions ………………………………………………………….………….48 Chapter 9- References ……………………………………...…………………....………….49

LIST OF FIGURES Fig. 1. State Level Pattern in India (2011) ……………………………………………………….………..….7 Fig 2. Hill Stations in Himalayas …………………………………………………………………..……….….8 Fig. 3. Development in Indian Hill towns ………………………………………………………..………..…..9 Fig. 4. Himalayan Range of Mountains …………………………………………………………..……….…11 Fig. 5. River system in Himalayas …………………………………………………………………..……..….12 Fig. 6. Cyclone Amphan caused flood havoc in Bangladesh ……………………………………..…..…..16 Fig. 7. Occurrence of Flash Floods …………………………………………………………………..…..…..16 Fig. 8. Glacial Lake Structure …………………………………………………………………………....……17 Fig. 9. Change in Padma River Morphology from 1988 to 2018 …………………………………………18 Fig. 10. Construction along Yamuna floodplains, violating the NGT orders ……………………….......19 Fig. 11. Temporal pattern of land cover and land use change during 1880–2010 ………………….....20 Fig. 12. Changes in the human population and built-up area in India during 1880–2010 ……………20 Fig. 13. Pollution in Himalayas …………………………………………………………………………..…...20 Fig. 14. Embankment failure and change in channel of river Kosi ……………………………………….21 Fig. 15. Incision produced by instream gravel mining ………………………………………………….....22 Fig. 16. Riverbed mining downstream of the Karcham Wangtoo Dam on the Sutlej River ……….......22 Fig. 17. Chennai International Airport build over Adyar river ………………………………………......23 Fig. 18. The Paraguay-Parana River before and after the construction of the Yacyreta Dam ……….23 Fig. 19. Camping and river rafting along Ganga river in Rishikesh, Uttarakhand …………………...24 Fig. 20. Bhakra Dam across Sutlej with installed capacity of 1379 MW ………………………………..25 Fig. 21. Mumbai’s British era drainage system failed …………………………………………………......25 Fig. 22. Map showing fusion of Westerlies and Monsoon clouds in June 2013 ……………………......28 Fig. 23. IMD image suggested heavy rainfall on the higher reaches of Uttarakhand …………………29 Fig. 24. Satellite view of Kedarnath showing drainage system, glaciers, lake and township ………...29 Fig. 25. Tropical rainfall measuring mission (TRMM) of NASA showing rainfall on 17 June 2013 ...30 Fig. 26. Kedarnath settlement before and after the flood ……………………………………………….....31 Fig. 27. Slum development in Flood plain ……………………………………………………………….......32 Fig. 28. Water logged drains of Dehradun ……………………………………………………………….....33 Fig. 29. Embankment along a stream in Dehradun …………………………………………………………35 Fig. 30. Diversion of access water for irrigational purpose …………………………………………......36 1

Fig. 31. Graduated land-use planning controls to reduce flood risk …….………………..……………..37 Fig. 32. Development of blue-green infrastructure along the stream …….………………..…………….38 Fig. 33. Structure of Expert System ……………………………………………..…………….……………...42 Fig. 34. Assessments done using Expert System and Decisions taken by various users using expert system ……………………………………………………………………………………………………………..43 Fig. 35. Simulation of flood situation using building footprint, floodplain delineation …...…………..46 Fig. 36. Drainage Network Analysis using Strahler Method in QGIS ………………………...…………47 Fig. 37. Slope Analysis in QGIS ……………………………………………………………….…..………….47

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LIST OF TABLES Table 1. Trends in Urbanisation in India, 1961-2011 ……………………………………….…..…...6 Table 2. Components of urban growth …………………………………………………………………………7 Table 3. Number of Dams in Himalayan Region and Installed power capacity …………………...…….8 Table 4. Basin-wise details of Glacial Lakes / Water Bodies in Himalayan Region …………………...17

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4

CHAPTER 1

INTRODUCTION India is a developing nation. Himalayas being a crucial part of Indian landscape, are also undergoing development. Like rest of India population boom and fast-growing urban expansion has taken toll over Himalayas. But majority of the development that is being carried out is unplanned and has turned its back to sustainability, which in the case of ecologically sensitive zone becomes a crucial player.

Due to fragility of the Himalayas, climate change, urbanisation and absence of resilience; these hills when exposed to some shock, end up in an unrecoverable state, added with huge life and economic losses. One shock leaves it more defenceless to the other shock.

Urban flood is most frequent and likely shocks of all. Despite of the known risk, towns fail to handle the situation every time and face tremendous loss accompanied with vulnerability.

Planners and development authorities must plan our cities to resist these shocks and should have proper disaster relief and preparedness plan.

1.1.

Aim

Aim of the research is to understand urban flood resilience in Himalayan region.

1.2.

Objectives

Various objectives in the procedure of understanding urban flood resilience in Himalayas are      1.3.

Studying urbanisation scenario in Himalayas.

Understanding flood related ecology and sensitivity of Himalayas.

Listing causative factors.

Devising solutions for flood resilience guided by factors of urban flooding.

Studying role of expert systems in building flood resilient cities.

Scope

Certain types of natural disasters are very likely to occur in particular parts of the world. For example, areas adjacent to coastline, lakes or rivers have higher probability to experience flooding problems than the land-locked areas. It may not be feasible to avoid disasters, but it is certainly possible to plan ahead of time so as to reduce its impact. There are the actions you can take beforehand. ( VULNERABILITY + HAZARD ) / CAPACITY = DISASTER A disaster occurs when a hazard impacts on vulnerable people.

The combination of hazards, vulnerability and inability to minimize the potential negative consequences of risk results in disaster.

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The problem lies in the complexity of finding the solution to floods. Planning and preparedness is a strenuous task when it comes to something as uncertain and dynamic as flood, further made complicated by social, economic and administrative shortcomings. Hence accurate analysis and prediction of the consequences of floods becomes important to build our cities stronger.

Expert system is a promising solution, which is in current use in developed countries like Japan, Korea, New Zealand, Finland, etc. While India is yet to build the technology to utilize it to full of its potential, making the most out of accessible technology is required.

In this wake, floods, available technologies and their use in planning and designing must be understood properly. A nicely programmed bridge between all this knowledge can help us take better decisions for our cities and ultimately make them resilient to disasters.

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CHAPTER 2

UNDERSTANDING URBANISATION IN INDIAN HIMALAYAS 2.1.

Urbanisation in India

Urbanization in India began to accelerate after independence, because of the country's adoption of a mixed economy, which gave rise to the growth of the private sector. Population residing in urban areas in India, in accordance to 1901 census, was 11.4%. This count rose to 27.86% according to 2001 census, and crossing 30% as per 2011 census, standing at 31.16%.

According to a survey by UN State of the World Population report in 2007, by 2030, 40.76% of country's population is presumed to reside in urban spaces.

Area under urban settlements (7933 towns) in India has increased from 77370.50 sq. km in 2001 to 102220.16 sq. km in 2011 showing 24850.00 sq.km of additional land area being brought under urban uses.

Census year

1961

Table 1. Trends in Urbanisation in India, 1961-2011.

Urban Population Percent urban Annual exponential (in million) urban growth rate (%) 78.94 17.97 -

1971

109.11

19.91

3.23

1981

159.46

23.34

3.79

1991

217.18

25.72

3.09

2001

286.12

27.86

2.75

2011

377.10

31.16

2.76

(Source: Census of India - respective censuses (www.censusindia.gov.in))

According to Bhagat & Mohanty (2009) (Table 2), there are mainly four components of urban growth in India:    

2.2.

natural increase migration to urban areas reclassification of settlements as towns or its declassification due to changes in the nature of economic activities and acquisition of urban characteristics the extension of boundaries of cities and towns.

Urbanisation in Himalayas

Like the rest of India, rapid urbanisation is happening in Himalayan region. Rural urban migration is among the main contributors to rapid urbanisation in the hills.

Urbanisation patterns in the mountains are inherently different from the plains. Despite their geographical limitations, the truth is that a large number of urbanisations is unplanned and it is making its progress at a rapid pace, in the Himalayas (Mukherji et al., 2018).

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Components

Urban increment Natural increase (of initial population plus intercensual migrants) Net rural-urban migration Net reclassification from rural to urban including jurisdictional changes and out growths

Table 2. Components of urban growth.

Population in million Percentage Distribution 1971- 1981- 1991- 2001- 1971- 1981- 199181 91 2001 11 81 91 2001 49.9 56.8 68.2 91 100 100 100 24.9 35.4 39.3 39.9 50 62.3 57.6

200111 100 43.8

9.3 15.7

20.6 35.6

10.6 10.8

14.2 14.7

18.7 32.3

18.6 31.4

18.7 19

20.8 21.5

(Source: Bhagat, 2018)

For instance, in the eastern Himalayan states in India, 48 new towns were added between 2001 and 2011 (Population Census of India 2001, 2011). Uttarakhand is among t the ten major source states of internal migration in India (UNESCO 2013a). Uttarakhand’s population data shows that many districts are witnessing negative population growth and there are over 1000 villages that became stranded (Pathak et al., 2017, forthcoming).

Fig. 1. State Level Pattern in India (2011) (Source: Bhagat, 2018) 8

2.3.

Potential of development in Himalayas

2.3.1. Tourism India is a favourite tourist spot and has picturesque hill stations, making Himalayas perfect tourist destination for nature lovers. Indian hill stations are popular among both Indian and foreign tourists.

Fig 2. Hill Stations in Himalayas (Source- www.mapsofindia.com)

Uttarakhand state in the Indian Himalaya being the place of important Hindu shrines like Badrinath, Kedarnath, Gangotri and Yamunotri and also the place of source of many sacred rivers including the Ganga, is highly known for the religious tourism. (Kala, 2014) 2.3.2. Natural Resources Himalayas act as the water tower for entire South Asia. Numerous rivers not only act as water source but also as source of alluvial sediments for the plains. Apart from water resources, it is also rich in minerals. Himalayas are home to sapphire, alluvial gold, copper ore, iron ore, borax, sulphur, bauxite, coal, lead, zinc, mica, gypsum, etc.

The Himalayan mountain system occupies only 18% of the geographical area of India, but is accountable for more than 50% of India’s forest cover and for 40% of the indigenous species to the Indian subcontinent (Rao et al., 2003).

2.3.3. Hydroelectric Projects According to The World Bank, 60% of India’s installed capacity is being contributed by conventional thermal power plants. Responding to the need of shift from non-renewable energy sources to renewable ones, Ministry of Power, Government of India is keen on harnessing the water potential in our country. Himalayas region, being rich in such resources, like glacier fed perennial rivers, glaciers, the highland lakes, rivers, springs and ground water, has seen some large and major hydroelectric projects (Sati, 2015). The energy potential at 60% of low flow in the rivers has been calculated to be 1,50,000 MW (Verghese & Iyer, 1993).

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Table 3. Number of Dams in Himalayan Region and installed power capacity.

Region Arunachal Pradesh Assam Himachal Pradesh Jammu & Kashmir Manipur Meghalaya Mizoram Nagaland Sikkim Tripura Uttarakhand

Number of Dams 4 4 20 17 4 8 1 1 2 1 25

Power Capacity (MW) 97.57 429.72 3,421.51 1,805.21 80.98 356.58 34.31 53.32 174.27 62.37 2,441.82

(Source: Central Water Commission (CWC) and Central Electricity Authority, Ministry of Power)

2.4.

Development pattern in Himalayas

The development of Indian hill stations/towns according to Banta P.K., can be categorized into four stages- pre-independence; post-independence; stage of socio-economic development; and present scenario of development.

Hill towns, such as Shimla, Nainital, Mussoorie and Dalhousie, established by Britishers had low density pattern of development. These hill towns/stations were planned to satisfy the needs of a definite population size, for example, Shimla was planned and designed to satisfy the needs of maximum population of 25,000 people.

Fig. 3. Development in Indian Hill towns (Source: Kumar, 2016)

Post-independence, various hill stations/towns became centre of administration, tourism, commerce, healthcare and education, and fascinated people from nearby areas due to

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employment opportunities. Because of which, hill towns witnessed large migration in this period.

Off late, Himalayas are undergoing massive pressure for development. Due to insufficiency in the existing pattern of development to handle the increased demand for residential, work places, recreational, commercial and educational areas for both residential and floating population, hill towns are expanding illegally and haphazardly (Pushplata & Kumar, 2009).

2.5.

Problems/issues of Development in Himalayas

With the onset of urbanisation, hills towns started facing problems. Some of these are:        

2.6.

Depletion of green covers Congestion Overcrowding Water scarcity Urban floods Landslides Pollution of streams and lakes Vandalising the scenic beauty

Challenges to Development in Himalayas

Development in the hills, especially towns and the surrounding areas is a difficult task, as hill/mountain regions are largely situated within or near highly sensitive, and at times fragile eco-systems. Moreover, with deteriorating climate, natural disasters have been surprising mountains of late. Landslides, soil erosion, flooding, the destruction of scenic capacity and other problems of environmental deterioration are few to name. Due to inadequate planning measure, these hill settlements are highly prone to irreversible damages and loss of human life and economy, leaving them more sensitive to such disasters. Any development in the hills requires utmost protection of the natural resource base, while giving the hill residents an opportunity to enhance their quality of life. In other words, it should be sustainable.

2.7.

Sustainable Development in Himalayas

The idea of sustainable development refers to environmental, economic and social sustainability. While planning to achieve sustainable development in hill areas, the objectives should be:   

To conserve the natural resources and the scenic capacities for the interests of the present and future generations To bring sustainable - social, institutional and economic development to local people.

To develop tourism in such a way that it will have minimum negative influence on the environment

Development so far in Himalayas seem to be unsustainable, evident from problems/issues faced by the towns of late.

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CHAPTER 3

WATER SYSTEM IN HIMALAYAS 3.1.

Indian Himalayas

The Himalayas, the loftiest mountain system in the world, form the northern limit of India.

That geologically young mountain arc is about 1,550 miles (2,500 km) long, extending from the peak of Nanga Parbat (8,126 metres) in the POK region to the Namcha Barwa peak in the Tibet. The breadth of the system varies between 125 and 250 miles (200 and 400 km).

Fig. 4. Himalayan Range of Mountains.

(Source: Google Earth)

Within India the Himalayas are categorised into three longitudinal belts: 3.1.1. Greater Himalaya (Himadri) The northern most ranges of Himalaya separated by “Main Central Thrust” constitute Greater Himalaya (Himadri) zone. The feature is filled with glaciers, snow covered peaks and huge longitudinal valleys. This range has a granitic core bounded by metamorphosed sediments; the breadth and altitude varying between 40-60 km and 5000-7000 m amsl, respectively.

3.1.2. Lesser Himalaya (Himanchal) This is a central chain of mountain ranges surrounded by the divides of “Main Central Thrust” in north and “Main Boundary Thrust” in south. The rocks are highly condensed and altered. The region consists of higher mountains cut into deep ravines. Altitude, in general ranges between 1000 to 5000 m amsl and width between 60-90 km.

3.1.3. Sub-Himalayan Tract (Shiwaliks) The foothill belt of this territory is built entirely of shiwalik sediments. These newer and river carried deposits derived from the Himalaya represent the latest phase of the Himalayan 12

orogeny. The southern slopes are steeper in comparison to the northern slopes. The broad longitudinal valleys in between the lesser Himalaya and the Shiwaliks are called ‘Duns’ in western Himalaya. This region is distinguished by fault scrap, anticlinal valleys and synclinal ranges; the width, varies between 5-30 km and altitude between 300-1000 m.

Drainage, morphology, climate, monsoon system is complex in Himalaya and are important aspects that tell us about the danger of floods and vulnerability to it. Following sections briefly discuss these aspects.

3.2.

Drainage

The Himalaya is drained by 19 significant rivers, of which the Indus and the Brahmaputra are the largest, each having catchment basins in the mountains of nearly 100,000 square miles (260,000 square km) in extent. Five of the 19 rivers, with a total catchment area of about 51,000 square miles (132,000 square km), seven belong to the Indus system. Of the remaining rivers, nine belong to the Ganges system—the Ganga, Yamuna, Ramganga, Kali (Kali Gandak), Karnali, Rapti, Gandak, Baghmati, and Kosi rivers—draining approximately 84,000 square miles (218,000 square km) in the mountains, and three belong to the Brahmaputra system—the Tista, the Raidak, and the Manas— which drains 71,000 square miles (184,000 square km) in the Himalaya. Bhagirathi and Alaknanda rivers are two river heads of Ganges river. Uttarakhand Himalaya in general and Alaknanda and Bhagirathi valleys in particular have been through some of the worst forms of catastrophies in recent times.

Fig. 5. River system in Himalayas (Source: www.officersiasacademy.com)

Glaciers also play crucial role in draining the greater elevations and in feeding the Himalayan rivers. Various glaciers occur in Uttarakhand, of which the largest, the Gangotri, is 20 miles 13

(32 km) long and is one of the sources of the Ganges. Most of the Himalayan glaciers are in retreat, at least in part because of climate change.

3.3.

Basin Denudation and sedimentation

A million tonnes of sediment are deposited by Ganga and Brahmaputra river, every year.

These huge loads of suspended sediment show the very high rate of exposure in their drainage basins. The standard mechanical denudation rate for the Ganges and Brahmaputra basins together is 365 mm 103 yr-1. Factors like, including mean trunk channel gradient, relief ratio, runoff, basin lithology and recurring earthquakes are majorly accountable for such high denudation rates. Out of the total suspended sediment load carried by these rivers, half is delivered to the coastal regions and the other half is deposited along the lower basin. Of the deposited load, more than half is deposited on the floodplains of these rivers and the left over is deposited within the river channels, resulting in alluviation of the channel bed at an average rate of about 3.9 cm yr-1 (Islam et al., 1999).

3.4.

Precipitation

Local assistance and location determine climatic variation not only in various parts of the Himalayas but even on various slopes of the same range. The average annual precipitation on the south slopes varies from 60 inches (1,530 mm) at Shimla, Himachal Pradesh, and Mussoorie, Uttarakhand, in the western Himalayas to 120 inches (3,050 mm) at Darjeeling, West Bengal state, in the eastern Himalayas. North of the Great Himalayas, at locations such as Skardu, Gilgit, and Leh in the Kashmir portion of the Indus valley, only 3 to 6 inches (75 to 150 mm) of rainfall occur.

There are two durations of precipitation: the moderate amounts brought by winter storms and the intense precipitation of summer, with its south-westerly monsoon winds. During winter, low-pressure weather proceeds into the Himalayas from the west and cause heavy snowfall.

Within the territories where western disruptions are felt, condensation takes place in upper air levels, and, as a result, rainfall is heavier over the high mountains. During that season snow accumulates around the Himalayan high peaks, and precipitation is lesser in the east than the west.

3.5.

Relation between elevation and rainfall

The Himalayas play a very crucial role in affecting the climate of India. It captures the monsoon winds from Arabian sea and Bay of Bengal and compels them to shed their moisture content within the Indian sub-continent in the shape of snow and rain, more noteworthy at the southern flops of the Himalayas. The 20th century rain profile reveals that, the one zone with maximum rainfall is located just near the foot of the Himalayas (Shivaliks), at an elevation of about 600 m to 800 m, and another zone at an elevation of 2000 m to 2400 m. A sharp decrement in rainfall is visible with the rise in altitude after the second zone of maximum rainfall is reached. However, elevation alone is not the only cause for orographic rainfall, as the geometry of topography, i.e., slope, aspect, hill-shade, continentality etc. and

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orographic folds play important parts in orographic improvement of rainfall (Smith, 1979; Anders et al., 2006).

Second zone receives more rainfall, but thanks to the natural slope, it doesn’t create urban flooding situation. However, Shivaliks have lesser slopes and elevation difference resulting in lesser natural drainage. Hence Shivaliks are more sensitive to urban floods then rest of the Himalayan zones.

3.6.

Monsoon floods in Himalayas – Past, present and future

During monsoon, the Himalayan rivers often face flood issues in the northern Indian states Uttarakhand, Jammu and Kashmir, Himachal Pradesh, Uttar Pradesh, Bihar, West Bengal and Assam due to severe rainfall and localised intense, with flooding occasionally being accompanied by landslides (Chalise & Khanal, 2001; Mohapatra & Singh, 2003; Sen, 2010; Vellore et al., 2014).

A 1000-year history of floods restored from slack water and floodplain deposits in Ganga catchment, states that 25 large floods occurred at an average interval of 40 years, excluding the uncertainties. On comparing the recent floods and history, it exhibits that the variation in flood frequency occur due to fluctuation in monsoon rainfall (Wasson et al., 2013).

Rupa Kumar et al., (2006) and Rajendran & Kitoh (2008) have used highly-accurate modelling, to project increased monsoon rain, by up to 40%, and increased rainfall intensity in the Upper Ganga catchment along the end of the twenty-first century.

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CHAPTER 4

URBAN FLOODING AND FACTORS 4.1.

Urban floods

Floods can be regarded as ‘the submergence of usually dry area by a large amount of water that comes from sudden excessive rainfall, an overflowing river or lake, melting snow or an exceptionally high tide’. Floods have numerous repercussions on human population, these can be primary impacts like causalities and property loss, secondary effects like pollution of water, loss of entire harvest and spread of water borne diseases or tertiary effects like economic misery, loss of tourism, deficiency of food, rebuilding costs, price increase etc.

(Ministry of Urban Development, 2016).

There has been a growing trend of urban flood disasters in India over the past few years, thereby severely affecting some of the major cities in India. The most notable amongst them are Hyderabad in 2000, Ahmedabad in 2001, Delhi in 2002 and 2003, Chennai in 2004, Mumbai in 2005, Surat in 2006, Kolkata in 2007, Jamshedpur in 2008, Delhi in 2009 and Guwahati, Delhi in 2010, Srinagar in 2014 and Chennai in 2015.

4.2.

Factors

Urban flood is not the outcome of one factor alone, but is caused by numerous factors. One natural phenomenon is often accompanied by city failures to make it a disaster. These factors can be natural and man-made.

4.2.1. Natural factors 4.2.1.1.

Topography

We already studied that topography can influence rainfall. Topography, at micro level, also affects flood situations. The accumulation or natural drainage of water depends upon how easily it finds its way to lower elevations to leave behind the subject place. Slope and elevation are two aspects of topography that decide the fate of water falling on a piece of land. Slope tells us the velocity and elevation tell is the destination of water.

Slope Given some slope, water under gravity move places. This movement is faster when the slope is steeper and slower when slope is flatter. In absence of slope the water becomes stagnant. In technical terms, the rate of runoff is inversely proportional to contour spacing.

Elevation Water has the tendency to move from higher to lower elevation. The difference in elevation of a city determines where the water will flow. Water does not move up and hence due to variation in the physical features, can get trapped in the sinks.

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4.2.1.2.

Meteorological Phenomenon Cyclones Tropical Cyclones cause more than normal rainfall and sometimes lead to floods. Some instances are Nada cyclone in Cuddalore (2018), Roanu cyclone in Sri Lanka and Bangladesh (2016).

Recently in Assam and Sikkim, the Puthimari and Jia Bharali rivers were puffed up after heavy rain brought by the remnants of Cyclone Amphan in late May 2020 (Fig. 6).

Fig. 6. Cyclone Amphan caused flood havoc in Bangladesh (Source: The Economic Times, May 21, 2020)

Excessive Rainfall Monsoon floods are most usual hydrometeorological disaster in Himalayan landscape.

Excessive rainfall can trigger other disasters like landslides.

Fig. 7. Occurrence of Flash Floods (Source: BBC News)

4.2.1.3.

Glacier Lake Outburst Flood (GLOF)

Glacial lakes are formed when glacial ice or moraines or natural depressions impound water.

These lakes normally drain their water through leakage in front of the withdrawing glacier.

The moraine creates topographic cavity in which the melt water is generally accumulated

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thus causing the formation of glacial lake. When this lake is perfectly sealed, melted water will gather in the basin until leakage or overflow limits the lake level.

The reservoir of the melt may sometimes be unsteady, causing a sudden release of large amount of stored water. Flash floods caused by the sudden outbreak of glacial lakes, called as Glacial Lake Outburst Flood (GLOF), are well known in Himalaya where such lakes had often been formed by landslides. GLOFs have huge potential of flooding in downstream areas, leading to disastrous consequences due to discharge of large volumes of water in such a short span of time. Usually, the consequences arising out of such circumstances are extremely unpredictable, primarily due to shortage of availability of sufficient data regarding rainfall intensity, location of landslide, confined volume and area and physical conditions of water bodies.

Table 4. Basin-wise details of Glacial Lakes / Water Bodies in Himalayan Region Basin Name

Glacial lakes

Water Bodies

Total

Brahmaputra

294

1099

1393

Ganga

178

105

283

Indus

31

321

352

Total

503

1525

2028

Source: Central Water Commission, India

In 1929, the outburst of the Chong Khundam glacier (Karakoram) caused a flood peak of over 22,000 m3 / second at Attock. Glacial outburst is among the few suspected reasons for the flash flood experienced in Sutlej River on the night intervening 31 July and 1 August 2000.

Fig. 8. Glacial Lake Structure (Source: www.antarcticglaciers.org) 18

4.2.1.4.

Landslide Dam Outburst Flood (LDOF)

Due to landslides along the river, huge amount of debris settles in the riverbed, creating a natural barricade for the river flowing down. This results in the accumulation of water and thus formation of landslide dam. This natural dam when gives way due to failure (since it is not designed to hold the load of water), results in outburst flow of water causing flood downstream.

The blockage in the course of the Parechu in China (Tibet) resulted by the landslide in 2004 gave way in 2005 and caused severe flooding and damage to infrastructure in Himachal Pradesh.

4.2.1.5.

Change in river channel

In recent historical times, severe human disruptions in catchments and river channels (Bravard & Petts, 1996) have resulted in river systems to continuously adjust rather than quickly adapt to new constraints (Gregory, 2006). Possible reasons are: 



Change of flow in river- Alteration in the volume of river, can widen or narrow the breadth of the river. Volume of water in river again depends on other factors like rainfall in its catchment, rate of glacier melt, etc.

Accumulation of silt- Accumulation of silt on a certain bank acts as barrier to water flow, forcing it to go around it, often over floodplains.

Fig. 9. Change in Padma River Morphology from 1988 to 2018.

(Source: NASA Earth Observatory)

Water seeks the path of least resistance. Engineering works often offer this resistance and hence can cause forced change in river channel.

4.2.2. Manmade factors 4.2.2.1.

Encroachment of floodplains 19

The encroachments along seasonal rivers and drains are prevalent in India. These places prove to be easily available to slums. Estimates show as much of 70 per cent of the Municipal Corporation land along the riverbeds is under encroachment as per City Development Plan 2007 (Jawaharlal Nehru National Urban Renewal Mission, 2007). Builders have been constructing progressively on recovered wetlands, flood plains and low lands of the city because these regions have a affordable land rate. What is unconventional, though, is that not just private builders, the government too, is building over such sensitive regions.

Damage to floodplains harms the riverine ecosystem, lessens groundwater recharge capacity and poses threats of flash floods. Enforcement of floodplain zoning regulation is a must to avert floods.

Floods in Mumbai (2005), Kedarnath (2013), Srinagar (2014), Chennai (2015) and Kerala (2018) resulted from human occupation of river floodplains.

Fig. 10. Construction along Yamuna floodplains, violating the NGT orders.

(Source: www.indiawaterportal.org)

4.2.2.2.

Increase in runoff volume

Urban flooding is significantly distinct from flooding in rural areas as urbanization results in more developed areas and impenetrable catchments causing flood peaks by up to three times (Gupta & Nair, 2009). Consequently, flooding occurs rapidly due to faster flow times (in a matter of minutes). As per a study carried out, the change and increment in urban constructed area over the past two decades in terms of built up density per/1000 persons increased from 41 ha in 1986, 62 ha in 1998 to 104 ha in 2011 (Singh et al., 2013). Thus, the surface outflow due to rains has increased considerably as the impervious layer has increased. Inabilities to deal with increased runoff have been one of the reasons of increasing urban floods. Rainfall runoff also relies on the amount of rain falling on the impermeable surface.

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Fig. 11. Temporal pattern of land cover and land use change during 1880–2010.

(Source: Tian et al., 2014)

Fig. 12. Changes in the human population and built-up area in India during 1880–2010 (Source: Tian et al., 2014)

4.2.2.3.

Pollution

Urbanization give rise to enhanced municipal solid waste (MSW) generation and unscientific handling of MSW deteriorates the urban environment and causes health hazards (Joshi & Ahmed, 2016). Scrutinizing the population, lack of education and insufficient technology to recycle waste, solid waste management and sanitation has become a Fig. 13. Pollution in Himalayas significant challenge in (Source: www.laughingcolours.com) Indian cities. Drains are not frequently cleaned and solid waste remains disposed in them by people. As a result, the clogged drains overflow the rain water on the roads. As the storm water drainage system is 21

not capable of draining the rain water it leads to flooding and other related problems such as disturbance, damage to roads and widespread and deposit the solid waste on roads and other places. Every year government spends lacks and lacks in cleaning of this river, but it is futile as it is not followed by any law to forbid people from again polluting it.

4.2.2.4.

Embankment failure

Embankment construction is a conventional way of preventing a river flooding an area. Due to failure of embankment, water breaches into floodplains and majority of its monsoon discharge and sediment load begins flowing over an area.

In August 2008, a flood check embankment along the Kosi River in Nepal terai breached, causing floods in North-East Bihar and Nepal. After the Kosi embankment got ruptured, the river’s waters started flowing through its older abandoned channels, seeking the path of least resistance and filling enclosed basins, low-lying lands and ponds (Dixit, 2009). Embankment was experiencing force of water and finally failed. Though there can be numerous reasons of embankment failure. Four of them are

   

Internal erosion Lateral displacement Bank erosion Overtopping

Fig. 14. Embankment failure and change in channel of river Kosi (Source: Dixit, 2009)

4.2.2.5.

Mining activities

Instream Gravel Mining Sand and gravel are used as construction aggregate for roads and highways (base material and asphalt), pipelines (bedding), septic systems (drain rock in leach fields), and concrete (aggregate mix) for highways and buildings. In many areas, this aggregate is obtained mainly from alluvial deposits, either from pits in river floodplains and terraces, or by in-channel (instream) mining, getting rid of sand and gravel directly from river beds with huge equipment (Kondolf, 1997). Mining straight away changes the channel geometry and bed

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elevation and may involve comprehensive clearing, diversion of flow, accumulation of sediment, and excavation of deep pits (Sandecki, 1989).

Fig. 15. Incision produced by instream gravel mining. a: The initial, preextraction condition, in which the river’s sediment load (Qs) and the shear stress (t) available to transport sediment are continuous through the reach. b: The excavation creates a nickpoint on its upstream end and traps sediment, interrupting the transport of sediment through the reach.

Downstream, the river still has the capacity to transport sediment (t) but no sediment load. c: The nickpoint migrates upstream, and hungry water erodes the bed downstream, causing incision upstream and downstream (Source: Kondolf, 1997)

Floodplain Pit Mining Floodplain pit mining reconstructs the large areas of floodplain into open-water ponds, whose water level usually tracks that of the main river carefully, and which are commonly segregated from the active channel by only a narrow strip of unmined land. As the pits are in close hydrologic continuity with the alluvial water table, questions are frequently Fig. 16. Riverbed mining downstream of the Karcham Wangtoo brought up that adulteration of Dam on the Sutlej River.

(Source: www.internationalrivers.org) the pits may lead to contamination of the alluvial aquifer (Kondolf, 1997).

4.2.2.6.

Interference in drainage system

Rail, Road, Bridges In mountainous areas, roads and railways often have to cross rivers, and it is crucial to build bridges with piers to cross them. However, the presence of bridge piers adversely affects river flooding. Bridge piers on river channels can cause hurdles for flood flow by undermining the cross-sectional area and inducing local eddy currents and high flow velocities, which may ruin the hydraulic structures and cause local erosions of the bed.

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For instance, the secondary runway of Chennai International Airport was also built right over the Adyar river. Most of the airport was constructed on the riverine floodplains, leading to massive flooding during the 2015 Chennai floods.

Fig. 17. Chennai International Airport build over Adyar river (Source: Google Earth)

Dams Dams disturbs the longitudinal consistency of the river system and disrupts the action of the conveyor belt of sediment transport. Dams trap sediment to some extend and most change the flood peaks and seasonal distribution of flows, thereby tremendously altering the character and functioning of rivers (Kondolf, 1997).

Fig. 18. The Paraguay-Parana River before and after the construction of the Yacyreta Dam in 1985 (Source: www.vox.com)

4.2.2.7.

Unplanned tourism activities 24

Water Adventure and Sports Mountains and rivers are the foundation for tourism.

However, certain undisciplined activities such as location of toilets within the submergence area of the river beach during rainy season, trekking in the forests and regular camp fires stand as potential threats to the immediate environment around the river. This can also put huge

Fig. 19. Camping and river rafting along Ganga river in Rishikesh, pressure on the area and lead Uttarakhand (Source: www.tripoto.com)

to negative outcomes such as soil erosion, increased contamination, natural habitat loss, increased pressure on certain endangered species and increased vulnerability to forest fires (Farooquee et al., 2008).

Cultural and religious festivals Evidently large growth in the number of pilgrims has caused unregulated growth of hotels, ashrams and dharamshalas. Tourism problems related to land use, safety, access, supporting infrastructure, etc. have not received the required level of attention, particularly in the fragile setting of the hilly regions. The challenges of sanitation and solid waste management remain unaddressed during festivals and hence form major contribution to river pollution.

4.2.2.8.

Alignment, Location, Design and Provision of Waterway i.e. Vents, Culverts, Bridges and Causeways

Roads and railway embankments cut across the drainage lines and may cause increase in vulnerability of the area, through which they pass, to flooding and drainage congestion, if they are not properly aligned, located and designed. Inadequate waterway in the form of vents/culverts/ bridges/causeways is another cause of increase in vulnerability to floods.

4.2.2.9.

Unplanned release of water from dams

When the water behind in reservoir reaches the potential of the dam, water must be released to prevent damage to the dam. Sometimes extremely large amounts of water need to be released during heavy rainfall in its catchment. This unplanned large release of water can sometimes cause flooding downstream.

In September 1998, the Bhakra Beas Management Board (BBMB) opened the Bhakra dam’s floodgates without warning after a freak cloudburst. Newspapers reported entire villages were washed away in a few hours, and placed the death toll at 1500 with another 500 missing.

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Fig. 20. Bhakra Dam across Sutlej with installed capacity of 1379 MW. (Source: South Asia Networks on Dams, Rivers and People (SANDRP))

4.2.2.10. Inadequate drainage infrastructure and maintenance Drainage Infrastructure, with potential of storm water drains smaller than the rainfall runoff volume, is considered insufficient. Public bodies’ focus is mostly on de-silting of storm water drains before monsoon and enlargement of the over-loaded infrastructure, but at a slow pace.

Urban flooding in Mumbai (2019) is a leading example. The major issue was the city's old drainage system, which is severely silted and damaged.

Fig. 21. Mumbai’s British era drainage system failed.

(Source, Hindustan Times, 2019)

4.2.2.11. Poor observation and forecasting by meteorological department Indian Meteorological Department (IMD) prepares “Regional Precipitation Study Report “based on previous data of local rainfall and projects of future precipitation. They also maintain rainfall distribution/flood levels, cyclones and tidal waves time series data and patterns to predict and issue alert on anticipated water logging/water surge (Ministry of Urban Development, 2016). Whereas, the Central Water Commission (CWC) is entrusted with monitoring of flood situation in India at the time of designated flood period by 26

observing water levels/ discharges along the major rivers and issuing flood forecasts to the local administration/ project authorities/ State Governments and other Central Ministries such as Home Ministry, NDMA/ NDRF etc.

Since it is sensor and simulation based, prediction can go wrong sometimes. Like in the case of Uttarakhand Flash floods, IMD had predicted, ‘very heavy rainfall’. But it turned out to be ‘extremely heavy rainfall’ and then a cloud burst. Unpredictability is the outcome of complex nature of weather in Himalayas.

4.2.2.12. Absence of administrative framework While natural hazards may not be controlled, the vulnerability to these hazards can be reduced by planned mitigation and preparedness of sustained measures towards reducing the vulnerability of the community to disasters. Government fails to tackle floods when they don’t have administrative framework for disaster management. The condition further deteriorates because of the multiplicity of agencies and absence of coordination amongst these agencies.

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CHAPTER 5

CASE STUDY 5.1. UTTARAKHAND FLASH FLOODS (2013) NATURAL FACTORS PREVAILANT LESSER HIMALAYAS The State of Uttarakhand, being part of the Himalayan region, is extremely vulnerable to natural disasters. Natural disasters, like earthquakes, landslides, avalanches, cloudbursts, hailstorms, Glacial Lake Outburst Floods (GLOFs), flash floods, lightning, and forest fires, etc. have revoked major disasters in the State.

On 16 June 2013, the State faced yet additional mega disaster, causing extensive damage and destruction, apart from serious casualties. The entire state was knocked off by very heavy rainfall and flash floods. Though all the thirteen districts of the state were affected, five districts, namely Bageshwar, Chamoli, Pithoragarh, Rudraprayag and Uttarkashi were the worst affected. The tragedy concurred with the peak tourist and pilgrimage season, certainly enhancing the number of casualties and adversely impacting the rescue and relief operations.

The negative impact of the disaster was most noticeable in the Mandakini valley of the Rudraprayag district. Torrential rains, accompanied with the probable collapse of the Chorabari Lake, led to flooding at the Kedarnath Shrine and the adjacent areas of Rambara, Agastyamuni, Tilwara, and Guptkashi.

Other pilgrimage centres in the area, including Gangotri, Yamunotri and Badrinath, which has thousands of devotees, as visitors during the summer season, were also affected. People in significant locations, such as the Harsil, Roopkund and Hemkund Sahib, were abandoned for days together. Over one lakh people were locked up in several regions of the State due to wrecked roads, landslides and flash flood-induced debris. As per the report made available by the State Government on 09 May 2014, a total of 169 people died and 4021 people were announced missing (presumed to be dead).

5.1.1. Causes Natural Causes The disaster essentially occurred due to wide spread heavy rains during the period 14-18 June, which resulted in flash floods in all the major river valleys in the State. Heavy rains provoked major landslide at numerous locations causing severe disruption in surface communications.

The intense rainfall in the territory was the result of convergence of the southwest monsoon trough and westerly disturbances (Figure 22), which led to the formation of dense clouds over the Uttarakhand Himalaya (Figure 23).

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Fig. 22. Map showing fusion of Westerlies and Monsoon clouds in June 2013 (Source: India Disaster report, 2013, National Institute of Disaster Management, Govt. of India)

As per the Indian Meteorological Department (IMD), the downpour in the State between 15 June and 18 June 2013 was measured at 385.1 mm, against the normal rainfall of 71.3 mm, which was in excess by 440%. Thus, it can be inferred that the disaster was the result of excess precipitation in a short span of time, which resulted in huge water discharge in various rivers and streams.

The worst repercussions of the disaster on human settlements was seen in the Kedarnath shrine area (Gaurikund to Kedarnath), the Mandakini valley, the Alaknanda valley (at Gobindghat and upstream), the Pindar valley, and along the banks of the river Kali in Dharchula region.

The Kedarnath region in particular was impacted the most as it suffered unprecedented havoc with very heavy loss of life and property. Kedarnath Dham township is stituated at an altitude of 3583m on the banks of the river Mandakini, which conceives from the Chaurabari glacier about 4 kilometers upstream. It is connected by a motorable road from Rudraprayag up to Gaurikund (40 kms) and thereafter through a mule track (14 kms), running along the Mandakini river.

As per the Geological Survey of India (GSI), heavy rainfall caused the melting of Chorabari Glacier at the height of 3800 metres. This resulted into eruption of the Mandakini River causing heavy floods in the Rudraprayag district and adjacent areas. It was also noticed that the heavy downpour between 15 and 17 June resulted in extremely high rise in the river 29

discharges. The rise in the river level was 5 - 7m, where the valley was wide and 10 – 12m where

Fig. 23. IMD image (17th June 2013) suggested heavy rainfall on the higher reaches of Uttarakhand.

(Source: India Disaster report, 2013, National Institute of Disaster Management, Govt. of India)

the valley was narrow. In the upper extends of the Mandakini river the stream gradient is high and valley outline is mostly narrow.

The gush of water running down from Kedarnath and Rambara areas brought enormous sediment load which consisted of huge rock boulders with diameter ranging from 3 - 10m. The heavy sediment load along with big boulders acted as a tool of devastation and obliterated everything that came in its way. The mammoth volume of water also induced toe erosion along all the river valleys, which in turn, triggered landslides at various other places.

Fig. 24. Satellite view of Kedarnath showing drainage system, glaciers, lake and township 30

(Source: India Disaster report, 2013, National Institute of Disaster Management, Govt. of India)

These natural causes can hence be categorised as follows:   

Heavy rainfall Landslides Chorabari lake overflow

: Meteorological factor : Geological factor : Glacial lake outburst flood

Fig. 25. Tropical rainfall measuring mission (TRMM) of NASA showing rainfall on 17 June 2013. The violet colour indicates rainfall of about 350 mm. White triangle denotes the location of Kedarnath (Source: http://trmm.gsfc.nasa.gov)

Manmade causes It cannot be denied that the massive rainfall at an unusual time was the main reason.

However, reckless human interference made it a disaster. Inadequate attention of geology geomorphology and fragile ecology in widening the urban areas including Kedarnath, establishment of various hydropower projects concurrently, inadequate road alignment with poor construction, incompetent consideration of slope stability and malfunctioning in the engineering techniques were major factors responsible for flash floods in Alaknanda Valley (Sati & Gahalaut, 2013).

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Fig. 26. Kedarnath settlement before and after the flood. Note heavy damage and widening of channels in the northern part.

(Source: http://bhuvan-noeda.nrsc.gov.in/projects/flood/)

5.2. DEHRADUN, UTTARAKHAND (ANNUAL FLOODS) MANMADE FACTORS PREVAILANT OUTER HIMALAYAS The Dehradun city is located in south central part of Dehradun district. Dehradun city lies at 30o 19’ N and 78o 20’ E. The city lies in Doon Valley which has the Himalayas to its north, the Shivalik range to its south, the sacred river Ganga to its east and the river Yamuna to its west. Urban flooding is a relatively serious problem in the city, particularly in the dense sections of the city and in the areas located along the river flood plains. Dehradun is majorly affected by water logging of streets and seasonal river flooding. The city has many big and small drains, but it is prominently drained by two rivers, namely Bindal and Rispana. These rivers remain out of water throughout the year excluding the monsoon time, when water level reaches the nearby low-lying areas. Each year more and more localities are being affected by virtue of water logging of streets in Dehradun.

5.2.1. Causes Topography The elevation of the city ranges in between 550m to 1000m above mean sea level. The borders are at closer intervals at the higher elevations, where as they are at further distances in the lower part of the city signifying that central part of the city is majorly a low-lying area with moderate slope. The variation in steepness of the slope is responsible for water 32

accumulation as overflowing water moves slowly in low lying areas creating problems in parts of the city.

Excessive Rainfall Dehradun experiences heavy to moderate showers during late June to mid-August. Most of the annual rainfall (about 2000 mm) is received during the months from June to September, July and August being the rainiest months of the season. This rise in precipitation quantity does not get way across the city as the city storm water sewer are not well developed for sudden the increase in surface runoff due.

Increase in Runoff volume Urbanization has given rise to more developed areas and reduced penetrable surfaces and free spaces. This has been obvious from the growth rate and increment in built-up statistics. The population of the city recorded a rise of 114% during the last two decades from 1991 to 2011 (Singh et al., 2013).

Encroachment on River beds The slum development along Bindal and Rispana rivers is evident in Dehradun. It has been notified by Dehradun Municipal Corporation that over 6000 encroachments are there on the Bindal River, and it is just not the slums but rich and powerful people encroaching the river bed too.

Fig. 27. Slum development in Flood plain. (Source: Bansal, 2015)

Damaged embankment Most parts of the embankments made available at various locations in Rispana and Bindal rivers cannot uphold the enormous pressure of increasing rain water and they get washed away every year.

Urban Storm Water Drains At most of the places the capability of storm water drains is smaller than the rainfall volume generated each year, moreover in some regions they are busted and not been mended.

Narrow Streets A narrow road induces and aggravates the flooding of the streets and roads for hours during rains. Especially when narrow streets face shortage of urban drainage infrastructure they act 33

as land locked spaces. As the streets are denser and narrower in the city centre and in the large population density areas, it causes severe water logging in these regions.

Fig. 28. Water logged drains of Dehradun (Source: Bansal, 2015)

Impact Pounding factors         

5.3.

River bed pollution Vulnerable urban services Vulnerable building material and construction Socio- economic vulnerability Aged buildings and Older constructions Damage to Infrastructure Different flooding water Depth Severe Traffic Jam throughout the city due to floods Health issues due to spilling garbage

Key Recommendations / Lessons Learnt

The Uttarakhand flash floods of 16 - 17 June 2013, were one of the worst-case disasters to strike Uttarakhand. Though the disaster fundamentally occurred due to natural hazards, the vulnerability to the hazard was enhanced manifold by anthropogenic activities. At the same time, in Dehradun, shortcomings in planning and preparedness are the main culprit. These disasters reveal several infirmities in method of development and preparedness. Few of the important lessons learnt and key recommendations are listed below: a) There seems to be uncontrolled, unplanned enormous growth of towns in the hilly regions as people are shifting from rural to urban settlements. For example, population increment rate of Rudraprayag district during 1981–1991, 1991–2001 and 2001–2011 is 17.4%, 13.7% and 6.5%, respectively. In major cities, like, Dehradun, growth rate is alarmingly high at 32.3%. Growth rate is also causing over exploitation of natural resources in that region. It is important to check and define the maximum admissible size of the town in the hilly region (Sati & Gahalaut, 2013). b) Flood Plain Zoning Act regulating construction within the flood plain of a river should be implemented strictly.

34

c) For clearance of all hydro-power and other mega projects in ecologically sensitive regions like Uttarakhand, the Disaster Impact Assessment (DIA) must be made compulsory besides Environmental Impact Assessment (EIA). d) Landslide risk zonation mapping is required. Efforts must be done to develop such maps and increase the public awareness about the utility of such maps. Using modern Geographical Information System tools, it is convenient to combine different information and generate such maps (Sati & Gahalaut, 2013). Development and enforcement of guidelines, regulations and codes for landslides is critical. a) Effective stabilization of slopes in shear and weak zones be undertaken using scientific techniques available at national/international levels. b) Blasting for developmental activities be avoided as it may destabilize the weak rocks in mountainous regions. c) A Special Central Programme be undertaken for development new roads and renovation of current roads in a scientific manner. d) Disaster management plans be reviewed on a regular basis and updated to ensure a functional structure and accountability for all actions initiated by the State Government to enhance preparedness. e) Investments in infrastructure development related to weather, glacial lakes, river flow monitoring, etc. are fundamental for improving the precision of risk mapping, thereby allowing more lead-time for warnings provided by IMD, CWC, GSI, NRSC, etc. f) Tourism related development should be strictly restricted along the river banks. g) An effective pilgrim control and regulatory body should be constituted for control and management of pilgrims/tourists. h) Sanitation must be paid attention to. Proper disposal systems should be devised and made available to the public. i) Desilting and excavation of drains to be carried beforehand. j) The community-based disaster management system at the local level must be given utmost importance and strengthened through appropriate training and awareness programmes. k) Need to combine the contributions of volunteers and non-governmental organizations in disaster response at the State level. This unification would be best accomplished at the district and local levels. NGOs should be involved in the planning process for their involvement in a joint response.

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CHAPTER 6

FLOOD PREVENTION, PREPAREDNESS AND MITIGATION 6.1.

Structural Measures for Flood Management

The major thrust of the flood protection programme undertaken in India so far has been on structural measures.

6.1.1. Embankments/Banks, Flood Walls, Flood Levees The embankment system in the river restricts the water body to its existing course and prevents it from overflowing the banks. Embankments are constructed generally with earth easily accessible from nearby areas. In developed areas where adequate space is not available or land is very expensive, concrete or masonry floodwalls are constructed. Embankments (including ring bunds and town-protection works are the most famous approach of flood protection and have been constructed comprehensively in the past. Embankments are designed and constructed to afford a level of protection to combat floods of a certain frequency and intensity or against the maximum recorded flood, depending upon the location protected and their economic justification.

Fig. 29. Embankment along a stream in Dehradun. (Source: Bansal, 2015)

6.1.2. Dams, Reservoirs and other Water Storages Lakes, low lying depressions, tanks, dams and reservoirs store significant proportions of flood water and the stored water can be released subsequently when the flood has receded.

36

Use of dams for defence against flood has always been controversial. It has proved to be both cause and solution of floods.

6.1.3. Channel Improvement A channel can be made to transfer flood discharge at levels lower than its prevailing high flood level by improving its discharge carrying capacity. Channel improvement aims at increasing the area of flow or the speed of flow (or both) to increase its carrying capacity.

6.1.4. Desilting/Dredging of Rivers Silting at places where the rivers emerge from the hills into the plains, at convex bends and near their outfall into another water body, is a natural phenomenon. Selective desilting/dredging at outfalls/confluences or native reaches can, however, be taken into account as a measure to solve the issues locally.

6.1.5. Drainage Improvement Surface water drainage obstruction due to deficiency of natural or manmade drainage channels results in flooding in many areas. In such cases constructing new channels and/or improving the potential of existing channels constitute an effective means of flood control.

6.1.6. Diversion of Flood Water

Fig. 30. Diversion of access water for irrigational purpose.

(Source: www.fao.org)

One of the is a useful means of lowering water levels in the river would be, diverting all or a small part of the discharge into a natural or man-made channel, lying among or in some cases outside the flood plains. The diverted water may be taken away from the river without returning it further downstream or it may be drawn back to the river some distance downstream or to a lake or to the sea.

6.1.7. Catchment Area Treatment/Afforestation Watershed management measures such as forming a vegetative cover i.e. afforestation and preservation of soil cover in connection with fundamental works like check dams, detention basins etc. functioning as a strong measure in reducing flood peaks and controlling the sudden runoffs in the hills.

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6.1.8. Anti-erosion Works Anti-erosion works are normally taken up only for protection of towns, industrial areas, groups of thickly populated villages, railway lines and roads where re-location is impossible on socio-techno-economic grounds, long lengths of vital embankments benefitting large areas.

6.1.9. Climate Conscious Building Design It is perhaps the most ancient technique of sustainable development in hill areas. Vernacular Architecture addresses the climatic problems by integrating it as a main element in design, and has advanced aesthetics as per the climatic conditions. Present-day building design in hill areas, woefully has not taken clues from the tradition, and most premises on hills ape the plains.

6.2.

Non-Structural Measures for Flood Management

6.2.1. Flood Plain Zoning It is natural for a river to overflow its banks in the event of torrential rainfall in its upper catchments and spill into the flood plains, which are basically its domain. Extensive and often unplanned use of flood plains by man disregarding the basic fact that it is part and parcel of the river leads to damage.

6.2.2. Land Use Analysis

Fig. 31. Graduated land-use planning controls to reduce flood risk.

(Source: Land Use Planning for Urban Flood Risk Management, 2017)

Planned use of the catchment area help reduce vulnerability to floods. Catchment area must be divided in zones based on their elevation and distance from the water bodies. Most secure 38

places must be reserved for critical utilities and service infrastructure followed by less vulnerable or more resilient uses.

6.2.3. Buffer Zone of no construction The basin area along the stream should be cleared of any existing settlements and used for the construction of blue-green infrastructure.

6.2.4. Blue-Green infrastructure Development of blue-green infrastructure helps in creating sink for the waters and there by recharging ground water.

Areas with green covers and trees usually have higher infiltration rates than lawn or pasture without trees because trees create firmer macropores. These macropores encourage more filtration of water at a faster rate. So, more trees and vegetation should be planted along the stream in its flood plain in the name of parks, riparian buffer, etc. This will help in reducing the rising levels of food waters.

Fig. 32. Development of blue-green infrastructure along the stream.

(Source: University of Kentucky Cooperative Extension Service, Lexington.)

6.2.5. Flood Proofing Flood proofing efforts help greatly in the mitigation of torment and provide early assistance to the people in flood prone areas. It is definitely an amalgamation of structural change and emergency action, not including any evacuation. The techniques adopted consist of provision of raised platforms for flood shelter for men and cattle, elevating the public utility installation especially the platforms for drinking water hand pumps and bore wells above flood level, promoting construction of double-storey buildings wherein the first floor can be used for taking shelter during floods.

In case of urban areas, certain measures that shall be taken up as soon as flood warning is received, are installation of removable covers such as steel or aluminium bulk heads over doors and windows, permanent closure of low level windows and other openings, keeping

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store counters on wheels, closing of sewer wells, anchoring and covering machinery and equipment with plastic sheets, etc.

6.2.6. Flood Forecasting and Warning Flood forecasting enables us to be warned, beforehand as to when the river is going to use its flood plain, to what extent and for how long.

6.3.

Regulation/Guidelines/Bylaws

Building regulations are prepared to give answers to two important questions, ‘what to develop’, and ‘how to develop’ in a city/town/area with an objective to preserve public health, safety, general welfare and environment (Gann et al., 1998). These are the set of rules, which are thrusted upon ‘development work’ in a city to provide statutory regulations on the planning, design and construction of buildings and associated works (El-Gamal et al., 2017).

Building regulations implemented in India are primarily inspired from National Building Code and are slightly different for hills due to complex topography. There are general guidelines and bylaws for individual municipal area in hills, but the variation in topography is even more unique. Predominant building regulations in hill towns are contextually inappropriate as they do not take into consideration the geo-environmental and natural context of every piece of land. As a result, even developments abiding rules end up impacting earth negatively and become vulnerable to harms.

These regulations still work for smaller projects, but in case of large developments like laying highways, construction of dams and bridges across rivers, etc, assessment of impacts on the environment, and possible natural hazards and its capacity to survive it is required.

Considering, the country’s huge history of spontaneous developments in many sectors without safeguarding natural resources, social and environmental concerns, government has made Environmental Impact Analysis (EIA) necessary for such projects.

6.4.

Environmental Impact Assessment

According to International Association for Impact Assessment (IAIA, 2009), EIA is ‘the process of identifying, predicting, evaluating and mitigating the biophysical, social and other relevant effects of proposed development proposals prior to major decisions being taken and commitments made’.

6.4.1. Process of EIA in India    

Screening: First stage is determining if the proposed project, requires an EIA and if it does, then the stages of assessment required.

Scoping: This stage recognizes the key problems and impacts that should be inquired further. This stage also specifies the borderline and time limit of the study.

Impact analysis: This stage of EIA determines and predicts the probable impacts of the proposed project and evaluates the importance.

Mitigation: This step in EIA suggests the actions to minimise and avoid the potential adverse environmental consequences of development activities.

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   

Reporting: This stage displays the result of EIA in a form of a report to the decisionmaking body and other concerning parties.

Review of EIA: It examines the capability and effectiveness of the EIA report and provides necessary information for decision-making.

Decision-making: It decides whether the project is rejected, approved or requires modification.

Post monitoring: This level comes into action once the project is commissioned. It verifies to ensure that the impacts of the project do not exceeds the legal standards and execution of the mitigation measures are in the manner as explained in the EIA report.

6.4.2. Components Components of EIA are listed below:  Land use  Geology, topography and soils  Hydrology and water quality  Air quality  Climate change  Ecology: terrestrial and aquatic  Noise and vibration  Socio-economics  Transport  Landscape, visual quality  Historic environment  Recreation and amenity  Interrelationships between effects  Cumulative impacts

 Summary of residual impacts 6.4.3. Challenges with EIA Due to such a tedious and tiresome process, many EIA approvals are obtained through corrupt and unfair measures. The use of human decision makers leads to partiality, blunders, corrupt practices and erroneous assessments. It further causes needless delays, inconsistent and subjective decisions. And in case of the Government being the judge and the jury, there is no clarity in relation to government’s development project (Gounder, 2013).

EIA in India has not grown satisfactorily due to inefficient potential of EIA approval authorities, shortcomings in screening and scoping, bad quality EIA reports, insufficient public participation and poor monitoring (Panigrahi & Amirapu, 2012). International experiences suggest that political factors have been the motivating force behind the introduction and practice of EIA (Elliott and Thomas, 2009). For EIA, India offers both political and technical challenges (Panigrahi & Amirapu, 2012).

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CHAPTER 7

EXPERT SYSTEMS AND GEOGRAPHICAL INFORMATION SYSTEM(GIS) 7.1.

Role of expert systems

Environmental impact assessments (EIA) involve identifying, measuring, and assessing impacts. The process is complex and requires ample amount of information for processing and analysing quantitative data, qualitative information as well as expert human judgements.

Usually, provided data is incomplete, subjective, and inconsistent. This challenge of gathering, processing, analysing, and reporting EIA information can be met by computer systems (Gounder, 2013). This is where expert systems come into play. The inference engine is presumed and expected to reason like a human expert based on the information provided.

The data and information in the knowledge base aid the reasoning process.

We can determine the activity’s potential and perilous effects in advance, through Expert system. The project can be further transformed to ensure such impacts are avoided, rectified or mitigated and that positive results are achieved. Alternatively, if the significant effects cannot be avoided or mitigated, the approving authority can make firm and well-informed decisions on whether to approve or turn down the project (Fiji – DoE EIA, 2008).

7.2.

Expert system fundamentals

The general construction of an expert system is elucidated in terms of six main components.

They are:      

The knowledge base, which is a accumulation of domain specific knowledge usually represented as rules based on IF-THEN logic.

External applications, with which the system interchanges data and information. For example, computer simulation models or GIS spatial data.

The user, who handles and controls the system, input information, select options, and generates the expected reports.

The user interface, it is the means by which the user communicated with other components.

The inference engine, which is the reasoning mechanism that manages the rules in the knowledge base to give the conclusions.

The system also incorporates information on various standards, mitigation measures, guideline documents, and laws and regulations.

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Fig. 33. Structure of Expert System 43

Fig. 34. Assessments Done using Expert System and Decisions taken by various users using expert system.

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7.2.1. The Knowledge Base Knowledge base is a specialized database that contains the relevant details in the form of rules/regulations to provide support in anticipating impacts from proposed project activities.

The knowledge base is supplemented with knowledge from other databases which contain information from domain experts like:              

Wildlife Hydrology Health Agriculture Forestry Resources Air and Water pollution Urban planning Rural Development Transport Tourism Climate Historical Conservation Disasters.

Additionally, the knowledge base consists of the table of required measurements and benchmarks to compare impacts to determine the level of impact. It forms the set of rules to be applied, which are constructed by codifying the experience and knowledge of experts.

These rules are often depicted in the following form: IF <a set of conditions is true> THEN <certain conclusions can be drawn>

7.2.2. The Inference Engine The inference engine manipulates the rules in the knowledge base to deliver the conclusions based on the information given as input into the system. The inference engine handles the reasoning operation by making assertions, hypotheses, and conclusions. It is via this inference mechanism that the reasoning strategies of human experts are impersonated.

The inference engine, functions as follows: IF ˂condition˃ [attributes] THEN ˂action list˃ Where conditions are expressions involving attributes like: IF ˂deforestation˃ [˃70%] THEN ˂reject OR mitigation AND relocation˃ IF ˂construction distance˃ [˂70 m from river] THEN ˂reject OR relocate˃

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7.3.

Uses of Expert systems

Use of expert system is not confined to floods only, it can be customised for various other disasters and areas of different scale. A flexible expert system can be made use to do following assessments:       

Social impact assessment Environmental impact assessment Disaster impact assessment Economic impact assessment Infrastructural impact assessment Life damage assessment Vulnerability assessment

These assessments can be done by disaster management authorities, planners, development authority, environmentalists, etc. A detailed description of who does what assessment to decide on what has been done in figure 33.

7.4.

Limitations of Expert Systems

Following are the limitations of expert systems for EIA:  High level of struggle required to develop the knowledge base, rule base, and/or geographic setting within the expert system;  Regular need to customize expert systems for different users (thus making them unrealistic for simple one-time applications);  Training and computer hardware that must be obtainable to adequately use the expert system; and  Absence of suitability of such systems for performing algorithmic problem-solving tasks.

7.5.

Geographical Information System (GIS)

A Geographical Information System is a system of hardware, software and procedures to facilitate the management, manipulation, analysis, modelling, representation, display of geo data to solve complicated problems regarding planning and management (Verma et al, 2016).

GIS can be utilized for hazard and vulnerability mapping and analysis, and also for the application of disaster or risk management measures. Information from different sources and scales can be combined as a series of layers. For example, building footprint, flood plain, catchment and streams can help us find buildings vulnerable to flood (Figure 35).

A precise representation of the basin topography is a vital asset in flood forecasting, emergency action and mitigation (Ahmad et al, 2011). Satellite technology allows us to simulate topography in the structure of Digital Elevation Model (DEM) or Digital Terrain Model (DTM). In India, National Remote Sensing Centre provides DEM data using Indian Space Research Organisation (ISRO)’s CARTOSAT 1 satellite.

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Fig. 35. Simulation of flood situation using building footprint, floodplain delineation in QGIS

A diversity of flood related assessments is possible over the DEM of subject area. CartoDEM products are utterly useful in:          

Contour generation Drainage network analysis Quantitative analysis of run-off and soil erosion Volume-area calculations Design of hydraulic structures Design of new road, rail and pipeline alignments Watershed planning Urban utility planning Landslide zonation River configuration studies and flood proofing

 Fly through visualization Remote sensors add further information required for above said assessments in the form of real time climatic data, pollution levels data that help us simulate real instances and better plan our cities.

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Fig. 36. Drainage Network Analysis using Strahler Method in QGIS

Fig. 37. Slope Analysis in QGIS, different colours represent different direction of slope or flow of water

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CHAPTER 8

CONCLUSIONS Urbanisation and climate variation have caused a lot of complex challenges to our cities.

Cities in Himalayas, that are in or near ecologically sensitive zones have proved to be most unprotected to these challenges. It is evident from the study that, the amount of urbanisation is inversely proportional to elevation. But frequency of disaster occurrences and their severity, leaves Himalayas cities equally defenceless to impacts. Similarly, urban settlements in higher altitudes encounter fewer floods but severe ones. While in the lower reaches, in Shivaliks, frequency is high and intensity is low.

The causative factors are different but the result is same. Flooding factors at higher altitudes are predominantly natural, whereas, in flatter areas, it is mostly poor urban planning and human interventions.

Natural factors are result of long-term impacts of urbanisation on environment and hence can’t be controlled all at once. Our decisions on every step of development at smaller scale and time, shapes the upcoming tomorrow of hill towns in long term, indicating the need of working upon manmade factors at present. Since it is impossible to cease development and expansion of cities, the path of minimum destruction and disturbance must be opted. While proceeding with any developmental work, its impact on environment and its resilience to disasters, flood in our case, must be assessed. We should know, ‘what to build’, ‘where to build’, ‘how to build’, ‘what will be the consequences’ and ‘how will to respond and react during floods.

With satellite technology, remote sensors and artificial intelligence in our reach, we can acquire huge volume of accurate data, and process it to decide upon how to take up development sustainably.

It is not feasible for any scale of development to be of zero impact. The role of experts and government is to devise regulations and guidelines on how much impact should be acceptable. Abiding the guidelines/regulation/bylaws and knowledge from experts on various domains, and based on simulated outcomes, planners and development authorities need to build cities resilient to floods and for that matter any other disaster.

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CHAPTER 9

REFERENCES Ahmad, F., Kazmi, S. F., & Pervez, T. (2011). Human response to hydro-meteorological disasters: A case study of the 2010 flash floods in Pakistan. Journal of Geography and Regional Planning, 4(9), 518-524.

Anders A M, Roe G H, Hallet B, Montgomery D R, Finnegan N J and Putkonen J 2006 Spatial patterns of precipitation and topography in the Himalaya; Geol. Soc. Am. Special Paper 398 39–53.

Bhagat, R. B., & Mohanty, S. (2009). Emerging pattern of urbanization and the contribution of migration in urban growth in India. Asian Population Studies, 5(1), 5-20.

Bhagat, R. B. (2018). Development Impacts of Migration and Urbanisation. Economic and political weekly, 53(48), 15-19.

Bravard, J.P., Petts, G.E., 1996. Human impacts on fluvial hydrosystems. In: Petts, G.E., Amoros, C. (Eds.), fluvial hydrosystems. Chapman and Hall, London, pp. 242–262.

Chalise SR, Khanal NR (2001) An introduction to climate, hydrology and landslide hazards in the Hindu Kush-Himalayan region. In: Tianchi L, Chalise SR, Upreti BN (eds) Landslide hazard mitigation in the Hindu Kush-Himalayas. International Centre for Integrated Mountain Development., India, pp 51–62 Dhar, O. N., & Rakhecha, P. R. (1981). The effect of elevation on monsoon rainfall distribution in the central Himalayas. Monsoon dynamics, 253-260.

Dixit, A. (2009). Kosi embankment breach in Nepal: Need for a paradigm shift in responding to floods. Economic and Political Weekly, 70-78.

Elliott M, Thomas I. Environmental impact assessment in Australia: theory and practice.

El-Gamal, S. M. A., Amin, M. S., & Ramadan, M. (2017). Hydration characteristics and compressive strength of hardened cement pastes containing nano-metakaolin. HBRC journal, 13(1), 114-121.

Farooquee, N. A., Budal, T. K., & Maikhuri, R. K. (2008). Environmental and socio-cultural impacts of river rafting and camping on Ganga in Uttarakhand Himalaya. Current Science, 587-594.

Fiji – DoE EIA (2008). Environment Impact Assessments [EIA] Guidelines – Department of Environment – Fiji. A Guideline for EIA Practitioner and Approving Authorities.

Government of Fiji, 2008.

INDIA, P. (2011). Census of India 2011 Provisional Population Totals.

IMD, 2013. A preliminary report on heavy rainfall over Uttarakhand during 16-18 June 2013. Govt. of India, Ministry of Earth Science, Indian Meteorological Department, Lodi Road, New Delhi, July 2013.

India. (2016). Urban Flooding Standard Operating Procedure.

50

Islam, M. R., Begum, S. F., Yamaguchi, Y., & Ogawa, K. (1999). The Ganges and Brahmaputra rivers in Bangladesh: basin denudation and sedimentation. Hydrological Processes, 13(17), 2907-2923.

Gann, D. M., Wang, Y., & Hawkins, R. (1998). Do regulations encourage innovation?-the case of energy efficiency in housing. Building Research & Information, 26(5), 280-296.

Glasson, J., & Therivel, R. (2013). Introduction to environmental impact assessment.

Routledge.

Goundar, S. (2013). Cloud-Based Environmental Impact Assessment Expert System–A Case Study of Fiji. International Journal of Artificial Intelligence and Expert Systems (IJAE), 4, 45-61.

Gregory, K.J., 2006. The human role in changing river channels. Geomorphology 79, 172– 191.

Gupta, A. K. and Nair, S. S., Comparative study of urban flood challenges in three cities of India. In Proceedings of International Hydrology Programme Conference on Flood Resilient Urban Environment, UNESCO, Paris, 25–27 November 2009.

Kala, C. P. (2014). Deluge, disaster and development in Uttarakhand Himalayan region of India: challenges and lessons for disaster management. International journal of disaster risk reduction, 8, 143-152.

Kondolf, G. M. (1997). PROFILE: hungry water: effects of dams and gravel mining on river channels. Environmental management, 21(4), 533-551.

Kumar, A. (2016). Impact of building regulations on Indian hill towns. Hbrc Journal, 12(3), 316-326.

Kumar, K. R., Sahai, A. K., Kumar, K. K., Patwardhan, S. K., Mishra, P. K., Revadekar, J. V., ... & Pant, G. B. (2006). High-resolution climate change scenarios for India for the 21st century. Current science, 90(3), 334-345.

Lohani, B., Evans, J., Ludwig, H., Everitt, R., Carpenter, R. & Tu, S-L. (1997).

Environmental Impact Assessment for Developing Countries in Asia. Volume 1 - Overview.

356 pp. Report for Asian Development Bank.

Mohapatra PK, Singh RD (2003) Flood management in India. Nat Hazards 28:131–143 Mukherji, A., Scott, C., Molden, D., & Maharjan, A. (2018). Megatrends in Hindu Kush Himalaya: Climate change, urbanisation and migration and their implications for water, energy and food. In Assessing global water megatrends (pp. 125-146). Springer, Singapore.

Panigrahi, J. K., & Amirapu, S. (2012). RETRACTED: An assessment of EIA system in India.

Pushplata, A. Kumar, Mid rise buildings in hill towns – a problem or an opportunity, Architecture + Design 26 (2009) 90–96.

Rajendran, K., & Kitoh, A. (2008). Indian summer monsoon in future climate projection by a super high-resolution global model. Current Science, 1560-1569.

Rao, K. S., Semwal, R. L., Maikhuri, R. K., Nautiyal, S., Sen, K. K., Singh, K., ... & Saxena, K. G. (2003). Indigenous ecological knowledge, biodiversity and sustainable development in the central Himalayas.

51

R.S. Jutla, Visual image of the city: Tourists’ versus residents’ perception of Shimla, a hill station in northern India, Tourism Geogr. 2 (2000) 404–420.

Sandecki, M. 1989. Aggregate mining in river systems. California Geology 42(4):88–94 Sardar MQ (2010). "Flood management techniques", August 11th 2010.

Sati, Vishwambhar. (2015). Natural Resources Potentials and Socio-Economic Status in the Indian Himalayan Region. Nature and Environment. 20. 48-58.

Sati, V. P. (2020). Himalaya on the Threshold of Change. Springer.

SATI, S. P. & GAHALAUT, V. K. (2013) The fury of the floods in the north-west Himalayan region: the Kedarnath tragedy, Geomatics, Natural Hazards and Risk, 4:3, 193-201, DOI: 10.1080/19475705.2013.827135 Schmitt, T. G., Thomas, M., & Ettrich, N. (2004). Analysis and modeling of flooding in urban drainage systems. Journal of hydrology, 299(3-4), 300-311.

Singh, Omvir, Poonam Arya, and Bhagwan Singh BS Chaudhary. 2013. “On Rising Temperature Trends at Dehradun in Doon Valley of Uttarakhand, India.” Journal of Earth System Science 122 (3): 1–26. doi:10.1007/s12040-013-0304-0.

Sen D (2010) Flood hazards in india and management strategies. In: Jha MK (ed) Natural and anthropogenic Disasters: vulnerability, preparedness, and mitigation. Springer, p 615 Smith R B 1979 The inCuence of mountains on the atmosphere; Adv. Geophys. 21 87–230.

Third ed. Australia: Federation Press; 2009. p. 279.

Tian, H., Banger, K., Bo, T., & Dadhwal, V. K. (2014). History of land use in India during 1880–2010: Large-scale land transformations reconstructed from satellite data and historical archives. Global and Planetary Change, 121, 78-88.

Town & Country Planning Organisation Shimla, Draft Development Plan for Shimla Planning Area 2021, TCPO Shimla, Shimla, 2011.

Vellore RK, Krishnan R, Pendharkar J, Choudhary AD, Sabin TP (2014) On the anomalous precipitation enhancement over the Himalayan foothills during monsoon breaks. Clim Dyn 43:2009–2031. doi:10.1007/s00382-013-2024-1 Verma, A., Kumar, A., & Tiwari, V. K. (2016). Role of Remote Sensing and Geographical Information System in Environmental Impact Assessment of Developmental Projects for Environmental Management. International Journal of scientific research and management, 4(9), 4543-4553.

(2017). Land Use Planning for Urban Flood Risk Management. World Bank Group.

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