AMPHIBIOUS ARCHITECTURE IN ASSAM

B. ARCH DISSERTATION REPORT

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam; Case Of Kamlabari Village Submitted By Avantika Chauhan B.Arch. IV Year 00426001618 Guided by Ar. Madhur Varshney

ARCHITECTURE DEPARTMENT BHAGWAN MAHAVEER SCHOOL OF ARCHITECTURE, JAGDISHPUR SONEPAT-131001 (INDIA)

GURU GOBIND SINGH INDRAPRASTHA UNIVERSITY 2021-2022

CANDIDATE’S DECLARATION I hereby declare that the dissertation entitled, “Amphibious Structures As A Solution To The Flood Prone Region Of Majuli Island Assam; Case Of Kamlabari Village”, submitted in partial fulfilment of the requirements for the award of the degree of “Bachelors of Architecture” in Architecture department, Bhagwan Mahaveer School of Architecture, Jagdishpur, under the guidance of Ar. Madhur Varshney, Assistant Professor, Faculty of Architecture, is my original research work, and the information taken from secondary sources is given due to citations and references.

AVANTIKA CHAUHAN (00426001618)

Date: 10.05.2022

Place: Jagdishpur, Sonepat (India)

CERTIFICATE

In the fulfilment of B. Arch. degree program, this is to certify that the above statement made by the candidate is correct to the best of my knowledge and belief.

Prof. Raja C.P. Singh Professor / Principal Department of Architecture Bhagwan Mahaveer School of Architecture, Jagdishpur

Ar. Madhur Varshney Assistant Professor Department of Architecture Bhagwan Mahaveer School of Architecture, Jagdishpur

ACKNOWLEDGEMENT

I would like to express my deepest gratitude from the core of my heart, to all the people who helped me with my journey. Without their help, the completion of this research would be impossible.

Firstly, I am highly in debited to Prof. Raja C.P. Singh - my principal Ar. Madhur Varshney - my research guide for their continuous guidance, helpful comments, and tremendous support at every stage of work. Without their valuable inputs, the research would not have been able to reach its final form.

Secondly, I would also like to thank my Parents & Siblings for the continuous insights and help they have provided to conduct my study along with their endless moral support. I am also very much thankful to Apoorva Prakash and Shreyash Gupta for their help in conduction of the case studies and friendly critiques during the process.

AVANTIKA CHAUHAN (00426001618) Date: 10 May 2022

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

ABSTRACT

Majuli Island located within the boundaries of Assam; India is regarded as the world’s largest inhabited river island engulfed by the Brahmaputra River. Although Majuli is a panoramic hotspot for diverse flora and fauna, yet constantly faces an alarming threat of being consumed by the floods of the Brahmaputra River anytime. Brahmaputra River changes its course over time causing hazardous threats to the local people resulting in loss of livelihood.

However, people living here either move to safer places or rebuild their houses at the same place for economic and social needs. This situation of people is causing congestion in cities and wastage of resources. So, to provide a more suitable way of living, there is a need to explore an architectural innovation that is suitable for flood-prone areas and could resist the damage caused due to floods.

The report presented is an attempt to understand the possibility of building amphibious houses for people living in this area. In this dissertation, I focus on Amphibious architecture, which is a unique technique to provide houses for flood resilience functioning in land and water. It is a space alternative for permanent static elevation with improved recovery from the disaster and it is achieved by buoyant foundation.

Keywords: Floods; Amphibious architecture; Resilience; Majuli

Structures;

Buoyant

Foundations;

Vernacular

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

Table of Contents LIST OF FIGURES ............................................................................................................. 1 CHAPTER 1. SYNOPSIS .................................................................................................. 3 1.1

AIM ....................................................................................................................... 3

1.2

OBJECTIVE.......................................................................................................... 3

1.3

SCOPE .................................................................................................................. 3

1.4

LIMITATION ....................................................................................................... 3

1.5

NEED OF THE PROJECT ................................................................................... 4

1.6 METHODOLOGY .................................................................................................... 5 CHAPTER 2. LITERATURE STUDY .............................................................................. 6 2.1 FLOATING ARCHITECTURE ................................................................................ 6 2.1.1 Basic principle of floating ................................................................................... 6 2.1.2Water building typologies .................................................................................... 6 2.1.3 Flood resilient amphibious house ..................................................................... 10 2.1.4 Parameters for designing an amphibious structure ........................................... 11 2.1.5 Types of floating foundations ........................................................................... 15 2.1.6 Materials for superstructure .............................................................................. 17 2.1.7 Advantages of Amphibiation Over Elevation ................................................... 21 2.1 MAJULI ISLAND ................................................................................................... 22 2.2.1 Introduction to the study area in Assam ........................................................... 22 2.2.1.2 Assam and Floods .......................................................................................... 23 2.2.2 Geographical location of Majuli ....................................................................... 24 2.2.3 Condition of Majuli During floods ................................................................... 25 2.2.4 Population of Majuli Island .............................................................................. 26 2.2.5 Vernacular architecture of Majuli ..................................................................... 27 2.2.6 Conclusion ........................................................................................................ 32 CHAPTER 3. CASE STUDY ........................................................................................... 33 3.2

CASE STUDY 1: MAASBOMMEL, NETHERLANDS ................................... 33

3.2 CASE STUDY 2: THE LIFT HOUSE, DHAKA, BANGLADESH ....................... 46 3.2

COMPARATIVE ANALYSIS ........................................................................... 59

CHAPTER 4. PROPOSAL AND CONCLUSION .......................................................... 61 4.1 PROPOSAL ............................................................................................................. 61 4.2

CONCLUSION ................................................................................................... 63

REFERENCES .................................................................................................................. 64

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

LIST OF FIGURES • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

Figure 1- News clippings of articles related to flood and amphibious structure Figure 2- Archimedes’ principle of buoyancy Figure 3- Terp with Church and Houses in Hegebeintum Figure 4- Permanent static elevation of homes in south Louisiana.

Figure 5- Pile dwellings in Germany Figure 6- Houseboat in Maharashtra Figure 7- Amphibious house in Netherlands Figure 8- Amphibious house working Figure 9- Comparison of normal and amphibious houses during flood conditions Figure 10- Four main components of Amphibious Houses Figure 11- Working of buoyant foundation Figure 12- Site section Amphibious Developments Figure 13- Concrete hull being prepared for foundation Figure 14- Floating pavilion in Rotterdam Figure 15- Floating pavilion in Rotterdam Figure 16- A house being constructed with timber Figure 17- Foundation made up of pneumatic stabilizing platforms Figure 18- Foundation made up of plastic bottles Figure 19- Lightweight steel construction Figure 20- Heydar Aliyev Centre / Zaha Hadid Architect; Figure 21- Ferrocement construction Figure 22- A house made of EPS panels Figure 23- Comparison of elevated house and amphibious house during flood Figure 24- In New Orleans, permanent static elevation disrupts a neighbourhood’s coherence and changes its character Figure 25- Flood prone areas of India Figure 26- Majuli between the two channels Figure 27- Continuous erosion of the Majuli Figure 28- Shrinking of the Majuli island from 1911–2001 Figure 29- Population distribution Figure 30- Typical floor plan of Mising Hut Figure 31- Mising house, granary, pig stay and duckary under the stilt Figure 32- Typical floor plan of Deuri tribe hut Figure 33- Deuri chang ghar, perforated floor, pig stay and duckary under the stilt Figure 34- Typical plan of a Sonowal Kachari House Figure 35- Sonowal Kachari house, fish catcher, duckary, granary, and cow shed Figure 36- Local materials -bamboo, straw, mud, thatch/coconut leaves, timber Figure 37- Maasboomel Site Figure 38- Floodable lands Figure 39- Location of Amphibius houses along lakeside in Maasbommel, Figure 40- Connectivity of Amphibius houses along lakeside in Maasbommel Figure 41- Orientation of Amphibius houses along lakeside in Maasbommel Figure 42- Site context of Amphibius houses along lakeside in Maasbommel Figure 43- Fabrication of concrete hulls on site Figure 44- A concrete hull is hoisted from the water into the dock of a amphibious home Figure 45- Positions and condition of Amphibious houses in normal and high-water levels Figure 46- Assembling of prefabricated wooden-frame houses Figure 47- Roof hoisting on top of prefabricated wooden-frame houses Figure 48- Flexible facility connections between two houses, before connection to the house Figure 49- Access Road and floating pier connecting amphibious and floating house Figure 50- Site sections showing floating and amphibious houses respectively Figure 51- Ground floor plan of amphibious House

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• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

Figure 52- Upper-level plan of amphibious House Figure 53- Lower-level plan of amphibious House Figure 54- Section of amphibious House Figure 55- Elevation of amphibious House Figure 56- (a)Amphibious house with garden and parking place, July 2005 (b) Same house afloat, January 2011 Figure 57- Floating homes seen from access road, July 2005 Figure 58- Amphibious house afloat, January 2011 Figure 59- The LIFT House Figure 60- Location of LIFT House along lakeside in Dhaka Figure 61- Connectivity of Amphibius houses along lakeside in Maasbommel Figure 62- Orientation of the LIFT house along lakeside in Dhaka Figure 63- Site context of the LIFT house along lakeside in Dhaka Figure 64- Site context of the LIFT house along lakeside in Dhaka Figure 65- Ferrocement foundation Figure 66- Calculation for depth of Waste bottle foundation Figure 67- Waste bottle foundation Figure 68- The LIFT house 8-unit residence design Figure 69- The vertical guidance post in LIFT house Figure 70- The LIFT house static on ground during dry season Figure 71- The LIFT house floating on water during floods Figure 72- Service spine under construction with two horizontal lintel bands Figure 73- Workers testing the water bottle foundation model for live load capacity Figure 74- Service spine finished and instalment of first bamboo structure complete Figure 75- Diagram of the rainwater harvesting and storage systems Figure 76- Diagram of the composting latrine system Figure 77- Diagram of the composting latrine system Figure 78- Photovoltaic panel installed on a thatched roof in rural Bangladesh Figure 79- Ground floor plan Figure 80- First floor plan Figure 81- Section through compost storage and dwelling Figure 82- Section through rainwater cistern and dwelling Figure 83- Elevation of the LIFT House Figure 84- Interior views of the LIFT house Figure 85- Extrior views of the LIFT house Figure 86- Used water bottles foundation Figure 87- A house made of bamboo

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Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

CHAPTER 1. SYNOPSIS 1.1 AIM The primary aim of the research is to study and analyze the concept of amphibious structures as a measure of minimizing and controlling the damage caused by the Brahmaputra River floods in the Majuli Island of Assam.

1.2 OBJECTIVE • • • •

To understand the fundamentals of the floating system in amphibious architecture and the current system in it.

To understand what an amphibious house is.

To analyze its response and its architectural characteristics in areas prone to floods.

To study the possibility of incorporating the amphibious structures in the Kamlabari village of the Majuli island, Assam.

1.3 SCOPE • • • •

To study the theories proposed by architects and engineers involved in amphibious development.

To explore materials that are stronger and lighter that can be used for these structures.

To study the new technologies which are being developed in this field.

The study will focus on housing and the resilient technique of amphibious structures used in vernacular homes of Majuli island.

1.4 LIMITATION •

• • •

The report is limited to analyzing the possibility of incorporating the use of amphibious structures in the flood-prone Kamlabari village of Majuli Island, Assam.

The calculation of loads is not taken into consideration.

Costing and estimation will not be done.

The study and development will be limited to addressing the issue of flood resilience in the individual housing units.

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Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

1.5 NEED OF THE PROJECT •

•

Water is one of the greatest assets under the possession of mankind. It is a source of life but when challenged, it also has the ability to destroy the whole life structure.

Throughout the history of mankind, floods have brought untold wealth and prosperity to civilizations. Yet at the same time Flood is the most prevalent and costliest natural disaster in the world which devastates both life and the economy to a large extent.

India faces floods almost every year, in varying degrees of magnitude. Based on the statistical details available so far, it has been estimated that annually 7.17 mha. of the area is affected by floods that claim 1654 human and 618248 cattle life annually.

Around 1.2 million houses are damaged by floods and the average annual losses in monetary terms came to the tune of Rs 5649 crores.

Figure 1- News clippings of articles related to flood and amphibious structure

• •

Here we need to understand that floods are not something which we have to prevent, it is the destruction of livelihood which has to be minimised or prevented.

Amphibious Structures are characterized as the method of architectural adaptation used to counteract and handle floods (long and short term). With this typology, water and architecture will combine to create adaptive and efficient management strategies.

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Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

1.6 METHODOLOGY

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CHAPTER 2. LITERATURE STUDY 2.1 FLOATING ARCHITECTURE 2.1.1 Basic principle of floating Archimedes’ principle: A body floating or submerged in a fluid is buoyed (lifted) upward by a force equal to the weight of the fluid that would be the volume displaced by the fluid. This force is known as the buoyant force.1

Figure 2: Archimedes’ principle of buoyancy; Source: Encyclopaedia Britannica, Inc.

2.1.2Water building typologies According to the foundations and the relationship to the water, water dwellings can be categorized into terp dwellings, static elevation, pile dwellings, amphibious dwellings and floating dwellings. Some types have been used for centuries while others are relatively new technique, such as the amphibious house. However, in the event of rising water levels, each type has proven resilience.

2.1.2.1 Terp Dwellings A terp is an artificial earthwork mound created to provide safe ground in the event of a rise in water levels. The first terps were built in the Netherlands during 500 B.C where tides from the nearby rivers affected daily routines. The terps were built up to 15 meters high and was intended to keep a house dry and provide enough space for cattle and food storage. Around 1000 A.D the inhabitants began to connect these mounds to prevent the sea from flooding their lands, commencing the formation of a permanent dyke system. The terp dwelling is connected to the land and remains dry until a maximum water level has been reached. Although it feels safer and more secure than a floating

1

Nikhila Nelson, 2019, Envisaging the scope of amphibious architecture in below sea level regions of Kuttanad, pp- 5

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Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

dwelling. But is not safe because there are no means of escape during extreme and unexpected high-water levels. Today few modern terps can be found throughout Europe one such example is the Bridge House in Achterhoek, Netherlands. The landscape architect removed the top layer of the soil throughout the property in order to make the soil less fertile for the replanting of indigenous trees. The soil was then reused to form a raised area beneath the house in the event of high-water levels, resulting in a traditional Dutch terp dwelling.2

Figure 3: Terp with Church and Houses in Hegebeintum, the Netherlands; Source: education.psu.edu

Figure 4: Permanent static elevation of homes in south Louisiana.

2.1.2.2 Static Elevation One of the most common methods is elevating a house to a required or desired Base Flood Elevation (BFE). When a house is properly elevated, the living area will be above all. Several elevation techniques are available. In general, they involve two techniques as discussed below: • •

Lifting the house and building a new or extending the existing foundation below it.

Leaving the house in place and either building an elevated floor within the house or adding a new upper story.

2.1.2.3 Pile Dwelling Pile dwellings are a type of housing built on top of concrete, steel or wooden poles and can be found in shallow water, coastal areas, or lakes where changes in the water level can be predicted. This type of dwelling typically rests 8-15 feet from the ground and has been used throughout the world as means of protection from water. In Indonesia, Singapore, and other countries these housing are called as "kelong" which are built for fishing. The "Nipa hut" is the primary type of housing found in the Philippines and a similar stilt house structure is also popular in Papua New Guinea. Thai stilt houses are 2

Heather Christine Anderson, 2014, Amphibious Architecture Living With A Rising Bay, pp- 8

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often built above freshwater and the "Palafito" is found in the tropical river valleys of South America.3

Figure 5: Pile dwellings in Germany; Source: unesco.germany.travel

Figure 6: Houseboat in Maharashtra; Source: https://www.freepressjournal.in/

2.1.2.4 Houseboats Houseboats began with the conversion of ships and fishing vessels into livable environments. These types of houses resemble a land-based property in its design and construction yet are buoyant enough to withstand the forces of water. In India houseboats are common on the backwaters of Kerala, on Dal Lake near Srinagar. House boats in Kerala are huge slow-moving barges used for leisure trips. They are used to carry rice and spices from different places in early times. These house boats are considered as a convenient means of transportation. It is about 60 to 70 feet long and about 15 feet wide at the middle. The hull is made of wooden planks that are held tightly by ropes and coconut fibre. The roof is made up of bamboo poles and palm leaves. The exterior of the boat is painted with protective cashew nut oil coat. The need for housing brought many workers to transform old fishing boats into residential dwellings. Some of the more modern examples of floating homes are those built by Dutch architects including Waterstudio, Aquatecture, Factor Architecten and Architecten bureau Marlies Rohmer. The trend to build residences on water has attracted many homebuyers in coastal countries.4

3 4

ibid 9 ibid 11

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Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

2.1.2.4 Amphibious Dwelling Amphibious housing is a dwelling type that sits on land but is capable of floating. During a sudden rise in water a house will be lifted by the water provided either by pontoons or a hollow basement in order to ensure it remains dry and will then return to the ground as the water recedes. By sliding along two vertical mooring poles that are driven deep into the ground the houses are capable of Figure 7: Amphibious house in Netherlands; rising vertically while restricting Source: anthroprocene horizontal movements on the water.

Although the amphibious house resembles a houseboat there are some essential differences between the two types. The hollow basement of an amphibious house is exposed when there is no water forcing designers to conceal the base in the ground or in water. The second difference is the distribution of forces in the base. When the property is sitting on land it lacks the even upward force of the water which it experiences when it floats making the basement larger than that of the barge of a houseboat. The biggest difference between houseboats and amphibious homes is their connection to land. Typically, amphibious homes are designed where water levels are moderate but are rarely prone to extreme flooding therefore all utility services can be connected to the municipal pipes whereas houseboats must contain all utilities within the structure. Examples of these houses can be found throughout the Netherlands most notably the Maasbommel water dwelling situated along the river Maas.5

5

ibid 12

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2.1.3 Flood resilient amphibious house Amphibious house is a building that rest on the ground but whenever a flood occurs, the entire building rise up in its dock, where it floats, buoyed by the flood water. The buoyancy system beneath the house displaces water to provide flotation as needed, and a vertical guidance system allows the rising and falling house to return exactly the same place upon descent. It works based on Archimedes principle: The mass and the volume of the house is less than that of water, and what determined its buoyancy.6

Figure 8: Amphibious house working; Source: The Hindustan Times, Cherry Maslen, October 19, 2014

The house itself sits in the ground and the floating base is almost invisible from the outside. Amphibious designs can vary to suit the location and owners’ preferences. The amphibious design allowed the floor level to be set less than 1m above the ground level instead of 2m, had the house been static. This enabled a 225sqm 3-bed dwelling to be constructed over three floors in place of the existing 1-storey 90sqm house without significantly increasing the ridge height, and therefore achieved full planning.7 These types of foundations are a proven, low-cost, low-impact flood protection strategy that gives vulnerable regions to enhance the flood resilience and improve its ability to recover from disaster. It is a sustainable flood mitigation strategy that allows an ordinary structure to float on the surface of rising flood water than succumb to inundation.

6 7

T S Adithya and K K Manoj 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1114 012037 Formosa, 2014, The Amphibious House, Baca Architects

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Amphibious construction is an adaptive flood risk reduction strategy that can works in synchrony with a regions natural cycle of flooding, rather than attempting to obstruct the flow of flood water. It is also a low impact Hurricane mitigation strategy that provide flood protection without increasing exposure to strong winds.

Figure 9: Comparison of normal and amphibious houses during flood conditions; Source: Anthropocene, Emily Anthes, September, 2018

An amphibious house consists of following main components: • • • •

Buoyant foundation Wet dock and debris control Vertical guidance posts Flexible utility connections

Figure 10: Four main components of Amphibious Houses; Source: construction.org modified by author

2.1.4 Parameters for designing an amphibious structure There are specific standards and guidelines to be followed to design an amphibious house to be liveable and perfect replacement for conventional houses. For an amphibious house to be of proper functioning the following criteria has to be followed: 2.1.4.1 Capability of floating The most critical design guidance factor which decide whether the home will actually will be able to float during flooding conditions. If the total weight of the entire home including the dead and live load of the house should be less than the volume of the water then the house can float. The buoyant foundation should also be water tight so that it won’t develop any cracks. A water tight walls and floor should be taken into 11 | Literature study

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

consideration so that the structure stands independently without any extra support.

Light weight building materials should be used to make the building equivalent to the volume of the water.8 2.1.4.2 Foundation Foundation is the important part of the structure to support the light weight structure and to float during flooding condition. Deep foundations are the structural component that transfer loads into deeper layer of earth material than a shallow foundation. Deep foundation includes pile foundation with driven pile, drilled shafts, and micro piles and grouted in place piles. Structure design engineers are responsible for calculating the pile design load and for providing other structural detail. With the site seismicity and the factored load, the structural engineer should calculate and derive the foundation technique and material for the proposed site condition.

2.1.4.3 Float line The float line is the line that denotes when the building will begin to float. According to buoyant principle, if an object displaces a volume of water which weights a greater than the object then it will float. Likewise, if an object displaces a volume of water that weighs less than the object then the structure will not float. The building will have a static square or rectangular foundation the volume of water can be altered only by the height of the building. This means that if the sea level rises the water volumes also expands, so if the sea level rises the structure with less weight than the sea water will float. The float line is to be designed for 5 feet below the pier if the water level rises and the grade becomes steeper it will not because the pier will be completely inundating at those points.

The basic equation for Archimedes force is as follows: U = G / (A x P) Where: U is the vertical drop below the water line (m) G is the dead load of the total building construction (kN) A is the area of the floating body (m²) P is the density of water (kN/m³)9

8 9

Nelson (n1) 12 ibid 13

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2.1.4.4 Buoyant foundation height calculation The Archimedes principle states that “the buoyant force of the submerged object is equal to the weight of the fluid that is displaced by the object.” The depth of the foundation is calculated by finding the dead load and live load of the entire structure.

The weight of the structure per square foot should be divided by the weight of the water which equals the depth of house will be submerged when floating.

Depth of the house submerged =

the total weight of structure per sq. ft The weight of the water

Figure 11: Working of buoyant foundation; Source: Formosa, The Amphibious House, Baca Architects, 2014

2.1.4.5 Structure type To make the structure float the selected material should be of light weight material. The foundation is made up of a strong concrete hull or of any other material and the structure above the foundation which will float should be made up of light weight material. These materials should also be water proof material and should promote insulation and other passive heating and cooling technique to be sustainable structure. A future measure to reduce the weight of the building is developed by light weight wood framing doors and windows.

2.1.4.6 Road and parking condition A separate parking garage for the cars can be constructed for the residents. The parking place can be provided near the house as in Maasbommel project or the parking lots can be provided in place for all the houses in community. Residents can park their vehicles in the parking garage and take bicycles or motorcycle to their dwellings. The parking space can be differentiated from the other place by the use of material and with a level difference. During flood condition these vehicles can be taken from the parking lots and placed in some safer place. The residents can use boats can their transport or during emergency conditions. The aluminium can be used for the pedestrian walkway. The aluminium is low in maintenance and does not become slippery in case of rain. The aluminium panel can easily be removed in case of any maintenance problem.10

10

ibid 14

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2.1.4.7 Utility access The utility access is a difficult criterion in designing an amphibious building or floating building. All the utility services should be provided for these amphibious houses also like any other normal residential house on land. The utilities will use this forced access point into the home to run water, sewage and electricity. This is a necessary step because modern practice of burying utilities will not be adequate for life on the water.

It is crucial that things such as height, utility access points, float lines, foot prints and other items are uniform across the development are to be considered and also an easy installation, flexible connection should be provided. As in Netherland the service pipeline can be long and flexible fixed from the land to the amphibious house so that when the structure rise with the flood water these long pipelines will also rise with the dwelling. These pipelines will be long during normal condition when the structure rests on the land but during flooding condition they will be suitable for the length. Another type of pipeline can also be provided for floating and amphibious dwelling. It includes the pipeline will break by itself when the structure starts to rise and when the building recedes the connection can be fixed by an easy installation method. The lighting and meter boxes can be placed above the entrance or in the entrance bridge so that they are not fluctuated because of water. The cables behind the meter box are umbilical and will vertically stretch as the house moves. The pipes passing to this meter boards and distribution boards can be preferably metal pipes, ductile iron or coated steel can be used.

2.1.4.8 Water maintenance The salt water will erode the structure and also moving water can accumulate sludge and other waste particle. With the year passes by a thick layer of sludge or waste materials can accumulate and also will damage the utility connection to the building and also erode the steel in foundation and walls. The house should be protected with good material that will prevent the materials from corrosion because of water. After the flood when the dwelling recedes down the flood water will bring any particles when it returns. It should be checked and maintain that no particle gets stuck in the dock portion of the structure. If anything, get struck then there will be a problem in smooth motion of the structure. Minimum height should be maintained from the water level because when the water level is low the dwelling will get stuck in the mud.11

Figure 12: Site section Amphibious Developments; Source: Amphibious Architecture and Design: A Catalyst of Opportunistic Adaptation? - Case Study Bangkok 11

ibid 15

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2.1.5 Types of floating foundations A number of companies construct floating foundations using a variety of materials and methods. Durability, cost and buoyancy are the key metrics that guided the invention of current technologies, and will guide the development of future technologies. Early Dutch houseboats used wood and steel hulls because they co-opted contemporary shipbuilding technologies for residential purposes. However, due to maintenance issues and the desire for more stability and comfort, newer houseboats typically use a hollow reinforced concrete box called a concrete caisson. This foundation lies mostly underwater, while the rest of the structure floats above. The environment within the concrete box is similar to a basement and can function as additional mechanical storage or living space. This foundation typology has transcended houseboats and many floating buildings use them because of their durability and affordability. For floating buildings, water depth is the main obstacle to using a concrete caisson foundation.

Since many of these buildings are manufactured offsite in dry docks, the building’s foundation cannot exceed the depth of the waterways it must traverse; and the heavier the building the deeper the caisson. If it does exceed this dimension, it can be hauled over land, but this adds significant costs to the project. An alternative to concrete caissons is flat buoyant foundations made from a hybrid of different materials; the combination must be waterproof, durable, buoyant, and strong enough to support the building. Unlike concrete caissons, these foundations are solid; they also draw less water making them optimal for shallow water sites. Since they sit higher in the water, they also tend to be less steady than the previous style, but engineers can account for this in the foundation’s design. The different types of floatation foundations are as listed below: 1.

2.

3.

4.

12

Expanded Poly Styrene (EPS) with concrete filling Concrete hull Pneumatic stabilizing platforms Plastic water bottles12

ibid 16

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2.1.5.1 Expanded Polystyrene (EPS) with concrete filling This system is based on a core of polystyrene foam EPS and a concrete shell. This system gives the possibility to build on water and results in less draught so it can be used in more shallow waters.

On top of these advantages the system is also unsinkable.

Regarding the environment the EPS (also known as Styrofoam) is a non-toxic and totally inert. EPS doesn’t decompose and it Figure 13: Concrete hull being prepared for provides therefore lifetime durability. foundation; Source: floating homes limited The moisture pickup over 30 years is measured at a maximum of 5-6%. The material is 100% recyclable. EPS is waterproof and doesn’t leach out or degenerate. Concrete is extremely long lasting therefore its carbon footprint is reduced over time. EPS is 96% air. It can create foundation from 10 sqm to several thousand sqms. They are unsinkable and conform to the strictest requirements.

Figure 14: Floating pavilion in Rotterdam; The lightweight construction gives Flex Source: inhabitat.com base floating platforms a considerable buoyancy and therefore also a large load bearing capacity. This system gives the possibility to construct on water at any sheltered location. Two existing references of EPS construction are the floating pavilion in Rotterdam and the floating greenhouse in Naaldwijk, Netherlands. 13 2.1.5.2 Concrete hull The hull is made from concrete which means there is no rusting and condensation is minimal. These are hollow boxes of reinforced concrete, with enough buoyancy from the interior airspace to support the concrete as well as the structure. Its designs include shockabsorbing connectors, incorporated structural cleats and pile rings, because the structures are monolithic and sealed, they cannot take on water and are

13

Figure 15: Floating pavilion in Rotterdam; Source: inhabitat.com

Rutuja Shekade, Amphibious Architecture in India, pp -59

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unsinkable unless broken. Ferro cement is cheap. They’d be fairly easy to connect to one another and small ones could be easily built on board. This is the most promising technology for protected waters.

2.1.5.3 Pneumatic Stabilizing Platforms A Pneumatic Stabilizing Platforms consists of multiple cylinders, made of steel or concrete or plastic. The air, which is enclosed in the cylinder by the deck on the top side and on bottom side by the water gives the platform its buoyancy. A disadvantage with open containers is that as depth increases, the air is compressed and displacement goes down. This floatation is cheap to manufacture and can be stacked for easy transport.

Figure 16: A house being constructed with timber; Source: constructor.org

2.1.5.4 Plastic bottles It utilizes plastic 2 ltr beverage bottles, which are extremely common, incredibly cheap and resistant to seawater. These bottles can be banded together into hexagonal grids of 7 bottles each. The grids are then stacked and layered to form a buoyant lattice.

Some sort of rigid surface then needs Figure 17: Foundation made up of pneumatic to be placed on top of the floatation. stabilizing platforms; Source: the millennial project 2.1.6 Materials for superstructure

2.0

2.1.6.1 Timber Work Advantages • Heat retaining • Soundproof • Moisture proof • Rot proof • Fire proof • Termite proof • Windproof • Healthy and environment Figure 18: Foundation made up of plastic bottles; Source: the millennial project 2.0 friendly Disadvantages • Timbers tend to silver or look old if left natural and unpainted.

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•

Timber maintenance can seem to be higher than other building materials.

2.1.6.2 Light weight steel Advantages • The strength-weight ratio of steel is highest in all materials, so it can be used to build large span space.

• Has good performances to withstand strong winds.

• The unique intensity and toughness of steel makes lightweight steel structure houses have better Figure 19: Light weight steel construction; Source: resistance to natural gbaikal.com disaster.

• Having a greater flexibility in architectural design, structural reconstruction can be easily carried out and non- load bearing walls can be removed, replaced, reconstructed easily.

• All steel products are recyclable and the coefficient of recovery can come to 66%, which is the highest in all artificial materials. Also, steel can be recycled without degradation.

• Steel can be processed into many prefabricated parts and standard and traditional parts in order to reduce the waste of construction site and save the cost of the project.

2.1.6.3 GFRC (Glass Fiber Reinforced Concrete) Glass fiber reinforced concrete is an engineered material that contains cement, polymers, and glass fibers that are ingrained in the cementitious matrix. The properties are influenced by the glass contents, mix design, and production process. GFRC is mainly used for external applications since it increases its load-bearing capacity. It produces an extremely lightweight yet durable material.

Figure 20: Heydar Aliyev Centre / Zaha Hadid Architect; Source: Archdaily.com

Advantages • GFRC concrete can be cast in thinner sections and is therefore as much as 75% lighter than similar pieces cast with traditional concrete.

• GFRC is light weight allowing for lighter foundation and reduces shipping costs.

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• • • •

High strength can be obtained by using GFRC, being tough and resistant to cracking. It has a high ratio of strength-to-weight.

Since GFRC is internally reinforced, other types of reinforcement are not necessary that may be complicated for complicated molds.

Since the materials have a fiber coating, they are unaffected by the environmental effects, corrosion attacks, and other harmful effects.

It is sustainable because it is uses less cement than equivalent concrete and also often uses significant quantities of recycled materials so GFRC is qualified as sustainable.

Disadvantages • • • •

Lack of expertise in the existing contractors Extensive planning during design phase needed Requirement of Free Space and Equipment Area during construction Price advantage only when done on scale 1

2.1.6.4 Ferro cement Ferro cement is the method of applying a mixture of cement, sand and water in layers on wire mesh and steel reinforcement. It is light in weight than the concrete and also it is waterproof due to its cement content and application methods. Metals commonly used is iron or some type of steel. It is used to construct relatively thin, hard, strong surfaces and structures in many shapes such as hulls for boats, shell roofs and water tanks. Ferro cement is a high versatile form of reinforced cement.

Figure 21: Ferrocement construction; Source: It is a type of thin reinforced concrete civilclick.com construction in which large amount of small diameter wire meshes are uniformly placed throughout the cross section. Mesh can be a metal or any other suitable material.

Mortar is used instead of concrete Portland cement. Its strength depends on two factor cement mortar mix and the quality of the reinforcing material.

Advantages • Basic raw materials are readily available in most countries.

• Fabricated into any desired shape.

• Low labour skill required.

• Ease of construction, low weight and long lifetime.

• Low construction material cost.

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•

Better resistance against earthquake.

Disadvantages • Structures made of it can be punctured by collision with pointed objects.

• Corrosion of the reinforcing materials due to the incomplete coverage of metal by mortar.

• It is difficult to fasten to Ferrocement with bolts, screws, welding and nail etc.

• Large no of labors required.

• Cost of semi-skilled and unskilled labors is high.

• Tying rods and mesh together is especially tedious and time consuming.

2.1.6.5 EPS (Expanded Poly Styrene) Expanded Polystyrene (EPS) or Extruded Polystyrene (XPS) is a Geofoam that is manufactured into a large lightweight block. The blocks vary in size but are mostly in 2m x 0.75m x 0.75m. This geofoam is a light weight void fill. It is used in many applications such as light weight fill, green roof fill, compressible inclusions, and thermal insulation and sometimes it is used in Figure 22: A house made of EPS panels; Source: drainage also. EPS panel is used in bartelsvedder.nl prefabricated structure for walls, roofs, and foundations. EPS insulated panels offer an innovative option related to construction as well as maintenance as compared to traditional constructions.

Advantages • Prefabricated EPS panel do not require skilled labour to erect the structure.

Building can be erected with local support with minimum training and as a result it saves the labour cost as well.

• Minimum maintenance • Design flexibility is a attractive advantage in prefabricated construction and panels are available in different thickness.

• Low density but it gives high strength.

• A cubic meter of EPC with a density of 16 kg/m3 has a buoyancy of 984kg.

• Long-term R-Value (“R” is the resistance to heat flow) • Energy efficiency • Constant thermal resistance • Measurable energy savings • Low cost • Dimensional stability 20 | Literature study

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Disadvantages • Geofoam should be treated to resist insect infestation. Insects like ants can burrow into the geofoam and will weaken the material. 14 2.1.7 Advantages of Amphibiation Over Elevation 2.1.7.1 Performance During Flood Events Unlike houses elevated to a fixed level, amphibious houses can easily accommodate varying levels of floodwater. A house with permanent static elevation will be damaged when the depth of flooding exceeds the height to which it is elevated, while amphibious homes are able to adapt to variable flood levels by rising as the water rises. The longterm degradation of protection that affects PSE due to soil subsidence and rising sea levels is alleviated by an amphibious building’s ability to maintain an elevation that is always above the surface of the water. The vertical guidance posts may easily be extended if increases in flood depths are predicted.

Figure 23: Comparison of elevated house and amphibious house during flood; Source: preventionwebnet.com

2.1.7.2 Social Benefits Compared to static elevation, amphibious systems are less disruptive to residents’ everyday lives. Buildings with permanent static elevation remove their occupants from street level, requiring long flights of stairs or the expense of installing an elevator. This presents an ongoing inconvenience to residents as well as creating a significant Figure 24: In New Orleans, permanent static elevation impediment for the elderly and disrupts a neighbourhood’s coherence and changes its others with impaired mobility. character; Source: preventionwebnet.com Amphibious buildings, conversely, are only slightly elevated off the ground to accommodate buoyancy elements, thereby enabling a greater degree of accessibility. Aesthetically, statically elevated house 14

Nelson (n1) 23

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may produce significant voids at street level whereas amphibious houses help preserve the original character of a neighbourhood.

2.1.7.3 Economic Benefits Amphibious construction also offers economic benefits compared to ordinary construction. In new construction, an amphibious system represents an additional cost over conventional construction due to the need for a more elaborate foundation system.

As a percentage of the total cost of new construction, this represents an additional 5 to 10 percent, but it provides a means to avoid the much greater costs associated with flood damage.

Amphibious retrofitting offers considerable cost savings in comparison to permanent static elevation. This is because PSE requires the replacement of the entire foundation system, whereas an amphibious retrofit retains the existing foundation, merely supplementing its ongoing gravity load-bearing function with systems to provide vertical guidance to resist lateral loads and buoyancy to provide uplift. Detailed cost comparisons show that amphibious retrofits on average range from 1/3 to ½ of the cost of PSE. In severe flood events, houses with amphibious retrofits are subject to less damage than those with no flood mitigation strategy or even those with no flood mitigation strategy or even those with PSE. The cost savings vary on a case-by-case basis, but amphibious construction generally offers significant benefits when compared to alternatives. 15

2.1 MAJULI ISLAND 2.2.1 Introduction to the study area in Assam The study area selected is Assam. Assam serves as a major gateway to the north-eastern corner of India. It shares borders with the countries of Bhutan and Bangladesh and is surrounded by the states of Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura and Meghalaya, which together with Assam, are called seven sister states of the country. To the east of Assam lay Arunachal Pradesh, Nagaland and Manipur, to the west lay Bangladesh and Tripura, whereas Mizoram and Meghalaya lay to the south of Assam.

The state is rich in water resources and has vast tracts of fertile land. Assam is also the third-largest producer of petroleum and natural gas in the country and has ample reserves of limestone. With its five national parks and 18 wildlife sanctuaries, the state is a biodiversity hotspot. Other potential areas of investment include power and energy, mineral-based industries, tourism and crude oil refining.

15

Elizabeth English, Thriving with water: Developments in amphibious architecture in North America

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2.2.1.2 Assam and Floods Assam is situated in a high rainfall area with an average annual rainfall 0f 2,546 mm.

About 60-70 per cent of the monsoon rain is received within a span of 3-4 months during May to August. Because of high rainfall in the state and upper its neighbouring areas, The Brahmaputra and Barak, the main two rivers cause major problems in the form of flood, erosion and drainage congestion in the plane districts. The recurring floods have extensively damaged the rural economy of the state with accounts of extensive sand casting of once fertile land specially on the North Bank of Brahmaputra as well as river bank erosion throughout the state, forcing rural family to migrate to towns.

The occurrence of multiple waves of flood during the monsoon period extensively damage crops, kills livestock and brings untold misery to the people. The number of people affected and the amount of damage have increased steadily over time. The National Flood Commission had estimated the area vulnerable to floods in Assam at 31.06 Lakh hectares against 335.16 lakh hectares for India. Assam, given the extensive size of its plains and flanked by hills on either side of both the rivers, is the most flood prone state of the region. It accounts for 9.4% of India’s total flood prone area. Based on the incident and extent of flood the state is categorised into two broad areas: chronically flood affected and occasionally flood affected.16

Figure 25: Flood prone areas of India; Source: mapsofindia.com

16

Parth Champaneri, 2018, Disaster Resilient Houses, pp 22

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2.2.2 Geographical location of Majuli In north east India, in the disaster-prone state of Assam, Majuli Island is surviving for its identity.

The world's largest inhabited river island encompassed by the Brahmaputra River. Majuli is at the risk of being swallowed by the Brahmaputra River anytime.

The river Brahmaputra divides into two channelsFigure 26: Majuli between the two channels; Source: mapsofindia.com the northern Kherkutia Channel and the southern Brahmaputra Channel between Dibrugarh and Lakhimpur Districts and both the channels join again about 85 km downstream at Ukhalchuk forming Majuli, the largest inhabited River Island in India.

The width of the island (North-South) varies between 10 to 15 km. The Majuli Island is a part of Majuli Revenue Circle. As per the revenue records, the area of Majuli revenue circle in the year 1950 was 1245.12 sq-km. It included entire reach of Brahmaputra water body up to the left bank along Sibsagar, Jorhat and Golaghat districts. But as per Survey of India map, the area of Majuli Island was only 733.79 sq km in the year 1914.

The Majuli island is an administrative Sub-division under Jorhat district. The island represents a colourful rainbow of cultural integration with 70% of its population belonging to tribal communities such as Mishing, Deori, Kachari and Koch Rajbongshi.

It has a population of 1.68 lakh as per 2011 census. Majuli Island has been under serious attack by the mighty Brahmaputra. Loss of land mass on account of erosion of Brahmaputra River bank has been regular feature for Majuli island.

The fury of the floods that Majuli encountered in 2017 can gauged by the fact that at least 50,000 people were affected by the flood and 49 villages and 1760 hectors of crop were damaged. Majuli has shrank from 1256 sq km in 1971 to only 524 sq km in 2016 loosing half of its area, 67 villages have eroded away by Brahmaputra Floods. The way to reach Majuli is a two-hour ferry ride from the mainland. The island is known for it's rich biodiversity, native tribal population residing in stilted homes. 17

17

Baleshwar Singh, 2011, Influence Of Landform And Geomorphic Process On Topographic Evolution Of A River Island

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2.2.3 Condition of Majuli During floods Majuli as the world’s largest riverine island has been severely affected by floods and the damages caused as a result to a severe extent. After the great earthquake of 1950, the island has witnessed tremendous changes in its morphology due to continuous changes of river channels. The great earthquake has swelled up the river bed of Brahmaputra by 3–4 m due to the deposition of heavy silts, which resulted in bankline erosion and floods in the island year after year. A distinct characteristic of the island is the presence of numerous mid-channel bars or islets (locally known as Chapori) resulting from the braided nature of the river Brahmaputra. Apart from these, there are numerous beels (wetlands), ox-bow lakes, and rivers in the island, which cover 14% of the total geographical area of the island.

Today, Majuli faces the dual fury of flood and bank erosion. Floods occur more than once a year. Recurring floods have been affecting the ecological balance, physical landscape, as well as biodiversity in Majuli. The flood causes havoc amongst people and their livestock living on the island. The continuous erosion rips off the geographical area gradually. The river island is receding every year: Of an area of 1345 sq km in 1891, no more than 640 sq km of land was left in 2008.Since 1991 out of 244 villages, 35 have been razed by the river. Studies indicate that if this process goes on, the island will disappear in the next 15–20 years. Uncontrolled and indiscriminate development along with ineffective flood control measures for the island have led to ever-increasing flood damages in spite of the millions of moneys invested in the flood management sector during the last decades. The density of population on the island in 1901 was 24 persons per sq. km, which went up to 146 persons in 1991. As per 2001 the density of population is 364 persons per sq. km in Majuli. This figure is higher than the 340 persons per sq km in the whole state of Assam. The decreasing total geographical area coupled with increasing population is creating economic instability and ecological imbalance on the historic island. The flooding, which causes loss of lives and damage to property, creates a sense of insecurity in the minds of the people.18

Figure 27: Continuous erosion of the Majuli; Source: Deepika Jauhari research

Figure 28: Shrinking of the Majuli island from 1911–2001; Source: Deepika Jauhari research

18

Siddhartha K. Lahiri, 2014, Morphotectonic evolution of the Majuli Island in the Brahmaputra valley of Assam, India inferred from geomorphic and geophysical analysis

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2.2.4 Population of Majuli Island Majuli is historically rich. It has been the mainstay of Assamese civilization for the past five hundred years. The dwellers of Majuli are mostly of tribal folk. These ethnic tribes are the Misings, the Deuris and the SonowalKacharis who migrated to Majuli centuries ago. The population distribution of these three tribes is as follows:

Figure 29: Population distribution; Source: Author

The ethics and culture of these tribes are as follows: 1. The Misings – The Mising tribe of Assam is concentrated mainly on the northern banks of river Brahmaputra. They are believed to be of Mongoloid origin and has settled along the banks of the river Brahmaputra mainly in upper Assam. They belong to the greater Tani community which comprises many tribes of Arunachal Pradesh. The Misings are the mixture of East Asian as well as the Southeast Asian sub-race of Mongoloid Race.

2. The Deuris - The Deuris are religious and were originally from the priest and worshipper community and depended mostly on agriculture for their livelihood.

They migrated from a place called ‘Sadiya’ which is located in the present Tinsukia District of upper Assam.

3. The Sonowal Kacharis -The Sonowal Kacharis are amongst the royal dynasties and are scattered in the districts of Sibsagar, Jorhat, Golaghat and in states of Nagaland and Arunachal Pradesh. During the reign of Ahom king some of the Kachariswere engaged in gold washing of the river sand. Hence, they were called the Sonowal or the goldwasher.19

Figure: Mising, Deuri and the Sonowal Kachari tribe; Source: Google images 19

Aamirah Salam, 2021, Tales of Traditions, Aspects of Adaptations and Stories of Sustenance of the Largest River Island of the World, pp 2089

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2.2.5 Vernacular architecture of Majuli 2.2.5.1 Mising Tribe Hut Stilt Bamboo Hut of the Mising Tribe– The Misings constitute 44% of the total population of Majuli and they are the most important and dominant tribal community of Majuli. They build their traditional vernacular houses by using locally available wood, bamboo, cane, reed, thatch etc. Misings are an extension of Burmese Mongoloid origin, they believed in staying in stilt houses.

A typical Mising house has following characteristics: • • • • • •

• • •

•

Entry to the house is from the east side.

Bedroom and sleeping spaces are in the North side.

Double height front portico generally used for grinding & handloom-related activities.

Stilt platform is 5 to 7 feet high in order to accommodate handloom and pig stay under it.

The animals living under the stilt floor also get a warmer living space.

Living spaces are huge - a big hall with a centrally placed open kitchen for a large joint family. Places around the fireplace act as a family interactive space. The fireplace keeps the house warm during winter.

The houses have perforated flooring for ventilation from the bottom.

Traditional granary on the raised platform which acts as storage for food and pulses.

The stilts also provide protection from wild animals especially from elephants as it’s believed that they do not attack houses built on stilts and therefore doesn’t destroy the granaries.

The grains in raised platforms also get protected from moisture, flood, insects, and rodents20

Figure 30: Typical floor plan of Mising Hut; Source: bibliomed.org

Legend:Front verandah 2. Back verandah 3. Fireplace 4. Sleeping space 5. Courtyard for grinding 6. Space for Head of family 7. Guest sitting place 8. Store 9. Pig stay under stilt floor (below 4, 6 & 7) 10. Handloom space 20

ibid 2091

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Salient structural features of a typical Mising house – • • • • •

Foundation: Bamboo columns are inserted underground up to a depth of1000mm.

Column: Separate bamboo column for flooring and roofing.

Flooring: Wooden flooring over bamboo stilt platform.

Wall: Bamboo split wall without plastering.

Roof: Thatch roofing over bamboo truss

Figure 31: Mising house, granary, pig stay and duckary under the stilt; Source: ijcrt.org

2.2.5.2 Deuri Tribe Hut Stilt bamboo Chang Ghar of Deuri tribe– The Deuri tribe constitute 31% of the total population of Majuli. The Deuri people build their traditional houses by using wood, bamboo, cane, reed, thatch etc. They believe in staying in Chang Ghar (raised platform hutment).

A typical Deuri house has following characteristics: • • • •

• • • • • • •

21

Entry to the house is from the east side.

Bedroom and sleeping spaces are on the north side.

They enjoy their drinks in the cantilevered portion of the entrance veranda.

They also built their houses on stilts which includes a big hall with a central kitchen for a large family. The area surrounding the fireplace acts as a family interactive space. The fireplace keeps the house warm during winter.

The lower part of the house is used as an enclosure for the animals.

The animals living under the stilt floor also get a warmer living space.

The floor is perforated for better ventilation and they used it to pass the unnecessary victuals to the animals.

Deuri people cook special meals in Dudepati– an attached change and dine sitting around the fireplace.

A raised platform remains enclosed to the house for cleaning.

Apart from the main building, a traditional granary is also built on raised platform next to main building.

The grains in raised platforms are hence protected from moisture, flood, insects and rodents.21

ibid 2094

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Figure 32: Typical floor plan of Deuri tribe hut; Source: bibliomed.org

Legend: 1. Verandah 2. Drinking platform 3. Sleeping space 4. Sitting for elders 5. Kitchen & fireplace 6. Hall 7. Store 8. Handloom space in entrance courtyard in front of 1 & 2. 9. Pig stay under the stilt floor (below 3, 6 & 7).

Salient structural features of a typical Deuri house – • • • • •

Foundation: Bamboo columns are inserted underground up to a depth of 1000mm.

Column: Separate bamboo column for flooring and roofing.

Flooring: Wooden flooring over bamboo stilt platform.

Wall: Bamboo split wall without plastering.

Roof: Thatch roofing over bamboo truss.

Figure 33: Deuri chang ghar, perforated floor, pig stay and duckary under the stilt; Source: Figure: Deuri chang ghar, perforated floor, pig stay and duckary under the stilt; Source: : ijcrt.org bibliomed.org

2.2.5.3 Sonowal Kachari house Constituting 18% of the total population of Majuli, The Sonowal Kacharis are another major tribal community of Majuli. Unlike Misings and Deuris, Sonowal Kachari people build their traditional houses in the ground with raised plinth by using wood, bamboo, cane, reed, thatch etc.

Typical Sonowal Kachari house has following characteristics: • •

The typical house of Sonowal Kacharis is two sloped single ridge house for joint family system.

Main Entry to the house is from South side.

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• • •

• • •

The interior is divided into partitions for sleeping and has a wide verandah where from the entry is made to the rooms.

Kitchen is generally kept detached from the main house but connected by the corridor.

In Sonowal Kachari tradition, kitchen has three divisions based on the use of the spaces. ‘Thapana’ is a place where prayer is done which is made of clay raised from the floor. This is the most sacred place of the house where only the family members can enter.

They construct the walls of the houses with bamboo mesh and plastered with cow dung and mud plasters.

Apart from the main house there is a traditional granary on raised platform, cowshed, poultry shed, ring well and pond.

They have a chotal (courtyard) in front of their houses.22

Figure 34: Typical plan of a Sonowal Kachari House; Source: ijcrt.org

Legend: 1.Bed space 2. Corridor 3. Prayer room 4. Dining space 5. Fire space 6.

Granary 7. Courtyard 8. Fish pond. 9. Ring well 10. Poultry shed 11. Cow shed

Salient structural features of a typical Deuri house – • • • • •

22

Foundation: Bamboo columns are inserted underground up to a depth of 1000mm.

Column: Bamboo column for supporting roof.

Flooring: Earth flooring over raised plinth.

Wall: Bamboo mesh wall with cow dung & mud plastering.

Roof: Thatch roofing over bamboo truss.

ibid 2095

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Figure 35: Sonowal Kachari house, fish catcher, duckary, granary, and cow shed; Source: ijcrt.org

2.2.5.4 Construction materials

Figure 36: Local materials -bamboo, straw, mud, thatch/coconut leaves, timber; Source: ijcrt.org

In vernacular architecture, only locally available materials are used in construction.

1. Bamboo Bamboo is the most common building material that is used for building construction. Bamboo has high Tensile strength and highly ductile (earthquakeproof) in nature. It is cost effective, sustainable, readily available, workable and easily replaceable or partially replaceable.

2. Straw Straw is the baled up dead plant stems of a grain crop, once the seed head has been harvested from the plant. It has virtually all its seed heads removed, and contains no leaves or flowers. It is a lifeless material, with a analogous chemical composition of wood. Straw is used as an energy efficient roof covering materials. It is easily available local material and required no skill labour.

3. Mud Mud is a mixture of water, cow dung, and clay. It is the most commonly used as plastering materials in vernacular architecture. It is easily available, cheap, and workable. It is used as a plastering material for bamboo mesh walls and as floor finishing material. Mud mixed with cow-dung has anti-termite properties.

4. Thatch / Coconut Leaves Thatching is the technique of roofing with dry vegetation such as straw, water reed, sedge, rushes, or heather, layering on the roof frame so as to shed water away from the roof. It is a very old roofing method and has been used extensively in Majuli 5. Timber Timber is one of the most commonly used materials in the vernacular architecture.

From flooring to roof truss, beam and columns, timber is used in many parts of house as an alternative to bamboo.

6. Tools Various types of knives are used for cutting purposes, each having its own individual utility. The khonta is used for digging purposes and ropes for tying 31 | Literature study

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purposes. Ropes for tying purposes and hammers are used for beating the timber or bamboo to create the desired joinery.23 2.2.5.5 Roofing Primary objective of vernacular architecture of Majuli is to provide shelter. The essence of shelter is to provide enclosed space achieved by covering the structure. Most popular form of roof is the pitched roof sloping on two sides and with gables at each end. In these types of roofs ridge takes some load while rafters take the most of the load. These roofs are able to carry burden of cladding such as thatch and reed. Pitched roofs have large overhangs to protect the wall from rain and sun.24 2.2.5.6 Floors and Floor Finishes • • • • •

Floors are either used for human activity or animal activity. Floors are on the ground or raised platform above the ground level Usually for the ground floor the upper layer of soil is removed and filled with more stable materials and then compacted Often in floors are plastered with mixture of cow dung and clay Compacted earth in Sonowal Kachari house Wooden planks over bamboo frame work in Mising and Deuri houses

2.2.6 Conclusion The wet tropical environments of both Majuli and North east India create a typical architectural style. The traditional vernacular architecture of Majuli has following characteristics: • • • • •

Open lay-out of living and family spaces Significance of the rectangular and L-shaped layout Sloping roofs and protruding eaves as response to tropical rain, wind and other natural elements Grilled windows and porous walls as response to tropical sun glare and humidity Some tribes build their houses in the stilts as response to overcome flood and wild animals.

The vernacular architecture of Majuli is not only an Indian style of traditional architecture but also it shows a gesture of cross-boundary and multi-cultural architectural styles of south-east Asia. The studies carried in these three ethnic tribes – the Misings, the Deuris and the Sonowal Kacharis highlight the uniqueness of traditional adaptation of planning.

The holistic amalgamation of society with locally available construction materials, labour, technology, and climate goes on to prove the sustainable aspects that exists in the rural architecture in this part of the world.

23 24

Amal Barman, 2020, IJCRT, Vernacular Architecture of Majuli, pp 11 ibid 12

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CHAPTER 3. CASE STUDY Dutch landscape is currently highlighted by a new way of living on the water such as floating and amphibious houses to adapt to a sea level rise and floods. In Gouden Kurst, Maasbommel is an innovative approach was taken in 1998. Bangladesh is known for two things: poverty and floods. It is a delta country burdened with draining large amounts of water from surrounding countries and a heavy monsoon season that have caused numerous severe floods with large scale destruction throughout the country. The LIFT House: an affordable, flood-resilient housing solution for the low-income families of Dhaka.

3.1 CASE STUDY 1: MAASBOMMEL, NETHERLANDS

Figure 37: Maasboomel Site; Source: by author

3.1.1 • • • • •

Introduction Location: Maasbommel, Netherlands Area: 266 Sqm per unit Architect: Dura Vermeer and Factor Architecten Buoyancy Material: Concrete with Rebar Project Year: Started in 1998 completed in 2005

Two-thirds of the Netherlands would be flooded without the protection of dikes. Large portions of the country are situated below sea level, which makes them extremely vulnerable during floods after even minor fluctuations in water level. 25 Figure 38: Floodable lands; Source: Association of Provincial Authorities, 2004 25

Waterland: Water Information Network, ‘History of Dutch Water Management

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3.1.2 Evolution of Amphibious Structure

Figure: Timeline showing the origin of Amphibious houses in Maasbommel, Source: by author

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3.1.3 Location and Connectivity The Dutch town of Maasbommel is part of the municipality of West Maas en Waal, in Province of Gelderland, Netherlands. The amphibious project is situated outside the dike ring in recreational area that is particularly vulnerable to flooding.26

Figure 39: Location of Amphibius houses along lakeside in Maasbommel, Source: by author

Figure 40: Connectivity of Amphibius houses along lakeside in Maasbommel, Source: by author

26

Wikipedia; Maasbommel

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3.1.4 Climate and Site Orientation

Figure 41: Orientation of Amphibius houses along lakeside in Maasbommel, Source: by author

3.1.5 Site Context

Figure 42: Site context of Amphibius houses along lakeside in Maasbommel, Source: by author

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3.1.6 The foundation: floating concrete hull In the Maasbommel project 23-centimeter-thick concrete hulls, weighting over 70 tons, were prefabricated on site, then hoisted into the water, moved to their location, put in place, and after that the wooden houses could be built on top.27 The floating and semi-floating homes are similar in construction: a concrete barge with a relatively light timber-frame construction on top. The concrete barges weigh 72 tonnes each, while the timber-frame constructions weigh around 22 tonnes. The low centre of gravity gives added stability. The concrete barges are made from ordinary concrete with an aggregate to render them waterproof. The joints are reinforced with an additional waterresistant sealing strip. The barges are approximately 2 metres high, and as such can only be used as basements or, if part of the home is designed with a split level, as bedrooms.28

Figure 43: Fabrication of concrete hulls on site; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

Figure 44: A concrete hull is hoisted from the water into the dock of a amphibious home.; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

3.1.7 The amphibious home concept As said, the Maasbommel project features two different types of houses. Fourteen houses are floating in water permanently. The other 32, under normal circumstances, rest on a concrete foundation in a dock dug out of the talus of the dyke. They are so called ‘amphibious’, they will adapt to the situation, and start floating as soon as the water level rises. An advantage of these amphibious houses is that they are more or less the ordinary home, including a garden, access from the road and a parking place. Also, the inhabitants will only feel that their house is floating when the area floods. In Maasbommel these floods, with water levels above 7 meters + NAP, occur on average once every twelve years.

27 28

2011, Project Review: Floating Homes, Maasbommel, Netherlands, pp 7 Urban Green-Blue Grids, Amphibious homes, Maasbommel, Netherlands

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3.1.8 Orderly rise and descent

Figure 45: Positions and condition of Amphibious houses in normal and high water levels; Source: from Project review: Floating Homes, Maasbommel, Netherlands,2011, modified by author

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Each pair of two houses is kept in place by two mooring pylons. These steel columns have been driven deep into the ground and extend up to twelve meters above NAP level. Even in case of extreme floods flowing over the dyke, the houses will be kept in place and will be able to withstand currents you would find on open seas. To keep both houses that share the set of mooring pylons stable they are connected by a steel framework. The fact that the houses are connected also limits the influence of waves on the structure, as the two houses together weight over 200 tons.

The concrete hull of an amphibious house rests on six concrete foundation piles. The same six piles are used to give a level basis for the floating homes at extremely low water levels.

As water rises the houses will slide up along the mooring pylons. The amphibious houses will be lifted out of their docks, that will fill up with water. To ensure an orderly descent after a flood, the docks and their surroundings need to be kept free of any obstacles at all time. If anything got stuck underneath a house as the water withdraws, this could hinder a level touchdown. The maintenance instructions provided with the project should ensure the attention of the owners and the estate manager for this matter.

3.1.9 Architecture and engineering The basis of the architecture and building engineering of the houses was to build a light weight structure on top of the concrete boxes. In this way the centre of gravity is kept as low as possible, ensuring maximum stability of the house while afloat. The basic timber frame structure, identical for all the houses, was prefabricated in the Czech Republic, and then transported to Maasbommel to be assembled on site. The roof, made out of steel and wood and covered with PVC‐roofing, was build on site and then hoisted on top of the houses.

The houses are designed based on the view of the water and the landscape: the arched roofs are low on the side of the dyke, rising towards the east, where the living room and master bedroom look out over the lakes north of the river Maas. To emphasize the individual expression of the houses different colours are used, while a variety of materials (wood, Trespa HPL panelling and stucco) forms a composition in each façade.

The distribution of weight over the concrete hull was calculated, to ensure a level position in the water. Because about 70% of the entire weight is in the concrete itself and another 25% in fixed parts of the construction, balancing the house proved not to be necessary.

While the house weights 97 tons, the average interior, including inhabitants, is only 4 tons.29

29

Project review, (n26) 9

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Figure 46: Assembling of prefabricated woodenframe houses; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

Figure 47: roof hoisting on top of prefabricated wooden-frame houses; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

3.1.10 Water, sewage, electricity and gas The basic facilities of the house hardly differ from those in ordinary houses in the Netherlands. The house is heated by a central heating system on natural gas, equipped with radiators. It has connections to the water, sewage, electricity and gas networks like any other house would have. The difference is in the connection of those facilities between the house and the pipelines on land. Boiten engineered an ingenious connection system, as illustrated below, that connects the amphibious houses. Between each pair of houses there is connection from the bottom of the dock to the side of the house. The length of this connection is oversized for ordinary conditions, but long enough to remain connected when the water rises. The floating houses are connected with the same type of flexible pipelines, but for these houses a main line is situated underneath the floating pier that leads to the houses.30

Figure 48: Flexible facility connections between two houses, before connection to the house.; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

30

ibid 10

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3.1.11 Infrastructure The amphibious houses are accessed by a road, running along the dyke at 7,4m above NAP level. A floating pier connects the floating homes to the same road. Though all facilities (electricity connections, sewage pumps, etc.) have been placed above flood level, the road itself is no longer accessible in case of a flood. When the amphibious houses start to float, once every twelve years on average, the road will flood and inhabitants will have to use a boat to get to the houses. In case of emergencies, fire fighters and ambulance personnel will not be hindered by a small flood. In case of higher water, they will use boats as well.

Figure 49: Access Road and floating pier connecting amphibious and floating house.; Source: by author

3.1.12 Further Safety Measures The final and most crucial measure to ensure the safety of the inhabitants is a good maintenance plan combined with a 'user manual' for the houses. The estate manager and the owners will have to check the systems around the floating piers and most importantly the facility connections and the docks of the floating homes. When a flood is announced, the user manual states when to inform inhabitants and run an extra check on all crucial points.31

31

ibid 10

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3.1.13 Site Sections

Figure 50: Site sections showing floating and amphibious houses respectively.; Source: Urban GreenBlue Grids, Amphibious homes, Maasbommel, Netherlands

3.1.14 Amphibious House: Floor Plans (a) Ground Floor Plan

Figure 51: Ground floor plan of amphibious House.; Source: Issuu, Amphibious Architecture, Elizabeth Fenuta

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(b) Upper-Level Plan

Figure 52: Upper-level plan of amphibious House.; Source: Issuu, Amphibious Architecture, Elizabeth Fenuta

(c) Lower-Level Plan

Figure 53: Lower-level plan of amphibious House.; Source: Issuu, Amphibious Architecture, Elizabeth Fenuta

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3.1.15 Amphibious House: Section and Elevation (a) Section

Figure 54: Section of amphibious House.; Source: Issuu, Amphibious Architecture, Elizabeth Fenuta

(b) Elevation

Figure 55: Elevation of amphibious House.; Source: Issuu, Amphibious Architecture, Elizabeth Fenuta

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3.1.16 Site Views

Figure 56: (a)Amphibious house with garden and parking place, July 2005 (b) Same house afloat, January 2011; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

Figure 57: Floating homes seen from access road, July 2005; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

Figure 58: Amphibious house afloat, January 2011; Source: Project review: Floating Homes, Maasbommel, Netherlands,2011

3.1.17 Inference Changing environmental and development conditions, climate change impacts including sea level rise, increasing populations, and urbanization, can lead to increases in the flooding risks and water-levels in river communities. The Maasbommel houses can adapt to these changes, always adjusting with the changes in the river level. Although rising sea levels will likely lead to the abandonment of some coastal communities, this area of Maasbommel can, theoretically, continue to be habitable for generations to come due to the adaptive nature of these homes.

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3.2 CASE STUDY 2: THE LIFT HOUSE, DHAKA, BANGLADESH

Figure 59: The LIFT House; Source: Project review: prosunarchitects.com

3.1.18 • • • •

Introduction Location: 120/3, Darussalam Mirpur Rd, Dhaka, Bangladesh Area: 100 Sqm Architect: Prithula Prosun Buoyancy Material: Hollow Ferro cement foundation and a bamboo frame foundation filled with used plastic water bottles • Project Year: Started in 2009 completed in 2010

The LIFT (Low Income Flood-proof Technology) House is a response to the need for sustainable, affordable housing in flood-prone areas of Dhaka for the urban poor. The city of Dhaka is incapable of providing basic services, such as access to water, electricity, and a sewage system. The LIFT house is self-sustaining in providing these services without relying on the city infrastructure. The house is designed to be constructed in any low-lying location within the urban and peri-urban areas of the DMA.32 Prithula Prosun, a graduate student in architecture at the University of Waterloo, has recently designed and built the first engineered and code complaint amphibious house in Dhaka, Bangladesh. It is also believed to be the first engineered amphibious housing project constructed outside the Netherlands and the United States. She calls the project LIFT House, which stands for Low Income Floating Technology. It was designed for implementation communities situated in low-lying, flood prone areas of Dhaka, and has the capability of floating in rising water.33

32 33

Prithula Prosun, 2011, The LIFT house, thesis by Prithula Prosuna, pp 58 Elizabeth Fenuta, 2010, Issuu, Amphibious Architectures pp 226

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3.1.19 Location and Connectivity The house is situated in capital city of Bangladesh, Dhaka beside a pond and close to the road that runs through the grounds of the HBRI in order to easily demonstrate the benefits of the project to visitors.

Figure 60: Location of LIFT House along lakeside in Dhaka, Source: by author

Figure 61: Connectivity of Amphibius houses along lakeside in Maasbommel, Source: by author

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3.1.20 Climate and Site Orientation

Figure 62: Orientation of the LIFT house along lakeside in Dhaka, Source: by author

3.1.21 Site Context

Figure 63: Site context of the LIFT house along lakeside in Dhaka, Source: by author

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3.1.22 The Foundation Two types of amphibious foundations were used in the LIFT house. An amphibious foundation allows a house to become buoyant, meaning it has the ability to float when surrounded by water. The LIFT house required a low maintenance, low-cost solution using local materials and labour that would be suitable for the urban poor of Dhaka.

Two solutions were designed to test the efficiency and reliability of the foundations1. A Hollow Ferrocement Structure

Figure 64: Calculation for depth of Ferrocement foundation, Source: The LIFT house, thesis by Prithula Prosuna

Figure 65: Ferrocement foundation, Source: The LIFT house, thesis by Prithula Prosuna

2. A bamboo frame filled with empty used water bottles

Figure 66: Calculation for depth of Waste bottle foundation, Source: The LIFT house, thesis by Prithula Prosuna

Figure 67: Waste bottle foundation, Source: The LIFT house, thesis

by Prithula Prosuna

3.1.23 The Initial Design Prosun’s original design began as an 8-unit residence, but the experimental prototype constructed has 2 units. Figure xxx is the initial rendered plan of the ground level displaying the showers, composting toilets, service stairs, and a vegetable garden, Dual access is provided allowing compartmentalization of living spaces. The amphibious housing units made of bamboo are attached with steel connectors to the brick service spine.

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Figure 68: The LIFT house 8-unit residence design, Source: The LIFT house, thesis by Prithula Prosuna

3.1.24 How it works Each of the two-unit dwellings is primarily made of bamboo and provides living and sleeping quarters for a single family. The central brick spine houses the plumbing, utilities and rainwater storage cisterns. The vertical guidance system is comprised of a steel pipe that is cast into the masonry service core with a slit cut along the front, facing the bamboo house. Inside the pipe, a smaller steel pipe (approx. 1 foot in length) is inserted that slides up and down inside the main pipe. The smaller pipe is attached to the bamboo dwelling with metal plates that pass through the slot in the larger pipe. 34

34

ibid 227

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Figure 69: The vertical guidance post in LIFT house, Source: prosunarchitects.com

Buoyancy of the bamboo dwelling units is achieved using two different systems: one of the dwellings has a hollow ferrocement foundation, the other is a bamboo frame foundation filled with recapped empty water bottles. The steel vertical guidance system attaches the bamboo dwellings to the brick and concrete service spine and the dwellings slipe up and down vertically.35

Figure 70: The LIFT house static on ground during dry season, Source: prosunarchitects.com

35

Figure 71: The LIFT house floating on water during floods, Source: prosunarchitects.com

ibid 227

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3.1.25 The service spine The service spine is constructed out of brick and reinforced concrete.

Kitchens, bathroom, composting toilet storage tanks and two types of water cisterns are located in this structure. The interior surfaces of the cisterns are lined with a layer of Ferro cement in order to stop moisture penetration.

The foundation for the service spine is a concrete slab on grade with a 15” thick perimeter brick wall with a height of 12”. The walls of the Figure 72: Service spine under construction with two service spine are 10” thick with two horizontal lintel bands, Source: lintel bands of concrete, one halfway prosunarchitects.com up, and the other at the top to strengthen the brick wall. Two sets of three lintels span across the interior of the service spine to reduce the risk of buckling of the brick walls. A line of dowels is also inserted at both the top and bottom connections of the brick walls to the concrete slabs for a stronger connection by preventing rotation. The top slab of the service spine is a usable exterior space accessed through the second floors of the dwellings, making it a safe space for exterior activities during a flood. This exterior space has a concrete floor and with a bamboo railing that is attached with steel rods, concrete, and steel clamps.36

3.1.26 The Construction At the beginning of November 2009, soil tests were initiated on the site. Excavation began on November12, 2009 and lasted for four days. On the fifth day, reinforcement for the concrete slab was set in place and two days later, concrete was poured for the foundation.

On November22, 2009 the team began constructing the brick walls for the central service spine to house the composting latrines and rainwater storage cisterns, which took 12 days to complete. While the masonry service spine was being constructed, bamboo was also obtained to construct the amphibious housing units and was later chemically treated. The first buoyancy element was then created for testing, using empty recapped plastic water bottles encased in a bamboo frame. Then the bamboo encased water bottle buoyancy element was tested with live load; four team members stood on top of the buoyancy element to test its capacity. Next a ferrocement frame was prepared in order to create one of the buoyant foundations. By January 5, 2010 the bamboo frames for both units were completely erected and ready to be clad. Next, woven bamboo cladding was attached to the bamboo structural frames of each unit to create the walls and windows. On January 26, 2010 the 36

Prosun (n32) 60

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LIFT house was fully completed and the opening ceremony was held on site in Dhaka, Bangladesh.37

Figure 73: Workers testing the water bottle foundation model for live load capacity, Source: prosunarchitects.com

Figure 74: Service spine finished and instalment of first bamboo structure complete, Source: prosunarchitects.com

3.1.27 Water, sewage and electricity Water A catchment area of 570 sq. ft. and the city’s annual rainfall of 100 inches allows the house to collect a maximum of 100,000L of rainwater. The two water cisterns combined have a capacity of 48,000L which will be adequate for 10 residents throughout the dry season.

Rainwater is collected from the roof and the top slab of the service spine in the first cistern and passes through a filter that traps dirt and insects. If small particles of dirt enter the cistern, the natural sedimentation process will settle these particles at the bottom of the cistern. Water is taken from 1ft above this level. Residents have access to this collected rainwater via a hand pump located on top of the service spine. This is the primary source of water for activities such as cooking, bathing, and washing clothes. Drinking water is further boiled. Used water from these activities is collected through a biosand filtration pipe that removes pathogens, chemicals, and all other unwanted substances. This filtered greywater is then accessed through another hand pump for use as the secondary source of water, mainly for toilets, washing, and irrigation. This method maximizes the collected rainwater to fulfil all water needs of the residents.38

37 38

Fenuta (n33) 227 Prosun (n32) 61

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Figure 75: Diagram of the rainwater harvesting and storage systems, Source: The LIFT house, thesis by Prithula Prosuna

Sanitation The sanitation system of Dhaka is a wasteful user of precious potable water and electricity The LIFT house redirects the responsibility of sewage disposal from a large centralized system to an on-site composting system, turning urine and solid waste into resources the residents can use.

The composting latrine system is designed to fit the principles of the Sulabh Toilet. This low-cost, hygienic dual pit latrine system was designed and applied in India by Sulabh, an organization dedicated to providing the poor with access to affordable toilets.

Unlike the Sulabh toilets, the LIFT house composting latrines divert urine and deposit into the soil of the garden through an underground pipe where it can be used as fertilizer.39

39

Figure 76: Diagram of the composting latrine system, Source: The LIFT house, thesis by Prithula Prosuna

ibid 64

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Electricity Electricity is derived from two 60W solar panels, one for each dwelling of the LIFT house.

Two Canadian manufactured solar panels were donated by Centennial Solar Inc. Each panel is connected with a local solar battery, wiring and fixtures to provide electricity for 1 fan and 5 energy saving light fixtures for each unit, one on each floor of the dwelling, one at the front door, one in the kitchen, and one in the toilet area, for a period of 6 hours a day.40

Figure 77: Diagram of the solar energy system in each dwelling of the LIFT house, Source: The LIFT house, thesis by Prithula Prosuna

Figure 78: Photovoltaic panel installed on a thatched roof in rural Bangladesh, Source: The LIFT house, thesis by Prithula Prosuna

3.1.28 The LIFT House: Floor Plans Ground Floor Plan The two amphibious dwelling is connected to the service spine. The dwelling 1 is made of empty used bottle foundation and the dwelling 2 is made up of hollow ferrocement foundation.

Figure 79: Ground floor plan, Source: The LIFT house, thesis by Prithula Prosuna 40

ibid 66

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First Floor Plan The first floor is accessed by internal staircase. At this level, the service spine is useable and consists of toilets, kitchens.

Figure 80: First floor plan, Source: The LIFT house, thesis by Prithula Prosuna

3.1.29 Sections of the LIFT House

Figure 81: Section through compost storage and dwelling, Source: The LIFT house, thesis by Prithula Prosuna modified by author

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Figure 82: Section through rainwater cistern and dwelling, Source: The LIFT house, thesis by Prithula Prosuna modified by author

3.1.30 Elevation of the LIFT House

Figure 83: Elevation of the LIFT House, Source: The LIFT house, thesis by Prithula Prosuna

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3.1.31 Site Views

Figure 84: Interior views of the LIFT house, Source: The LIFT house, thesis by Prithula Prosuna

Figure 85: Extrior views of the LIFT house, Source: The LIFT house, thesis by Prithula Prosuna

3.1.32 Inference The LIFT House represents Bangladesh: an embodiment of what is important to the country, its people, its environment, its economy, and its water. The house can become a symbol of the country’s reaction to climate change, where the rise in sea levels is not seen as a threat, but a circumstance to which one adapts. The house reconciles this land with its water. It is a balance between the old and the new, indigenous materials with modern technology. It responds to the crisis of floods, environmental degradation, and the housing needs of the urban poor. These major issues are all currently being tackled by the country, which is why the LIFT house became part of the national dialogue.

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3.2 COMPARATIVE ANALYSIS S.no Parameters Maasbommel Project 1. Location Maasbommel, Netherlands

2.

3.

4.

5.

6.

Year of completion Area Max rise during flood Buoyancy Material

Super structure material

2005

The LIFT House 120/3, Darussalam Mirpur Dhaka, Bangladesh 2010

Rd,

266 Sqm per unit 50 Sqm per unit 18 feet 5 feet

Concrete Rebar

Inference

-

with Hollow Ferro cement foundation and a bamboo frame foundation filled with used plastic water bottles

In both the studies, the material used for the foundation efficiently solves its purpose of being buoyant and float during flood conditions but the recapped empty plastic water bottles used in one of the two LIFT houses is remarkable.

Since it not only reuses the harmful plastic waste but also allows easy replacement of any damaged bundle, without affecting others, in case of any bundle damage.

Timber for Bamboo for Both the projects used dwelling units dwelling units and light weight locally and steel for roof masonry for available materials for the service spine construction, i.e, timber and steel in Maasbommel and bamboo and clay bricks in LIFT house that reduces the cost considerably.

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S.no

Parameters

7.

Vertical Guidance System

8.

Buoyant Foundation

9.

Services

Maasbommel Project Foundation Boxes come in semi-detached pairs, connected by a deck, each pair is set is set into a niche in the river bank and held there by 2 large steel posts which are responsible for the vertical movement.

70-tonne concrete box provides buoyancy and forms the basement on which the wooden superstructure is built.

The LIFT House

Inference

Foundation Boxes come in semidetached pairs, connected by a deck, each pair is set is set into a niche in the river bank and held there by 2 large steel posts which are responsible for the vertical movement.

In each of these case studies, housing units are joined by sharing a common element that provides lateral resistance and is responsible for the vertical movement. For the amphibious houses in Maasbommel, two houses share a platform that provides lateral stability.

For the LIFT house, a central, fixed masonry spine provides both stability and vertical guidance.

In Maasbommel, 70% of the entire weight of the house is in the foundation which shifts its centre of gravity towards bottom and stabilizes the house while floating

Buoyancy is achieved from two different systems: one of the dwellings has a hollow ferrocement foundation, the other is a bamboo frame foundation filled with recapped empty water bottles.

Flexible pipes It is selfare attached to sustaining in city providing these infrastructure services without relying on the city infrastructure

The LIFT house is a selfsustaining house which is independent on the services provided by local city infrastructure which makes it more efficient and usable in remote areas which are severely affected by floods.

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CHAPTER 4. PROPOSAL AND CONCLUSION 4.1 PROPOSAL As we studied in the report, about the damage caused by floods in flood prone areas of Assam specifically Majuli and how amphibious houses can be used to counteract and handle floods in these areas. This tested and emerging technology is a flood-mitigation approach that is adaptable, cost-effective, and can preserve the community integrity of Majuli and other flood-prone areas. By implementing the technology of an amphibious structure which is its ability to float and come back to ground with respect to the water level, we can reduce the damage of resources caused by floods.

A proposal has been presented here to fight against the flood damages caused in Majuli.

Some key guidelines which should be followed while designing an amphibious structure are• • • • •

Floating capacity Buoyant foundation Super structure Material services Height of the vertical guideposts

According to these guidelines some recommendations for the construction of an amphibious house on our selected area and which can be followed in numerous numbers of places in Majuli is presented here.

Recommendations – As the people of this area are of low economic strata and are extremely comfortable with their own vernacular architecture. Keeping this in mind, we would provide some low-cost material recommendation also which will not destroy their architecture style and make them feel same as they feel today about their space.

4.1.1 Buoyant foundation Many materials for buoyancy of amphibious house are readily available in the market worldwide. But for this area I would recommend to choose used water bottles which is incredibly cheap and with this we can help our environment as well. As studied in the LIFT House, Dhaka, it is extremely sustainable and successful technique.

Figure 86: Used water bottles foundation; Source: squarespace.com

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4.1.2 Material used for superstructure As we know lightweight materials are required for the construction of amphibious house, so bamboo can be a good option. It had been used extensively as the traditional construction material in Majuli from ancient time onwards and bamboo joinery is the traditional craft skill used by the people here. Bamboo as a building material has high compressive strength and low weight. Thus, weight of a bamboo building is less than that of a masonry building and is suit to the soil whose bearing capacity is low. A prefabricated unit of bamboo or wood can be constructed within the factories and possible to transport and install at the site of construction.

Figure 87: A house made of bamboo; Source: housing.com

4.1.3 Roof EPS panels within a wooden structural frame work is preferred for roofing. It repels water, prevents humidity and bacterial growth. As its closed porous structure consist of 98% air, it is light, and does not place additional load on building. EPS application is quick and easy due to its flexible and light weight structure. Therefore, it saves time and keep labour costs low. The cost of EPS products for construction sector is lower by approximately 1/3 compared to other alternative products. It provides excellent thermal insulation and the material is heat, cold and fire resistant in nature.

4.1.4 Services It is suggested to use flexible pipes to connect the houses to the city infrastructures but it is also known that during floods these connections generally collapses in the remote areas.

So, it is suggested to build a house with solar panels to generate electricity and rainwater harvesting systems to utilize the rainwater. Thus, this house has minimum dependency on city infrastructure.

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4.2 CONCLUSION Water is one of the greatest assets under the possession of mankind. It is a source of life but when challenged, it also has the ability to destroy the whole life structure. India faces floods almost every year, in varying degrees of magnitude. The country faces massive devastation as an unfortunate consequence of these floods in various different states.

Around 1.2 million houses are damaged by floods in the country almost every year. Assam is one of the most severely affected flood-prone regions of the country in which lies the world's largest riverine island "Majuli". Majuli island is an administrative subdivision under the Jorhat district and always lies at the risk of being swallowed by the Brahmaputra River anytime.

Therefore, the primary aim of the research is to study and Analyse the concept of amphibious structures as a measure of minimizing and controlling the damage caused by the Brahmaputra River floods in the Majuli Island of Assam. The study clearly envisages the importance of bamboo-based amphibious housing as an effective solution to overcome the possible difficulties caused by rising water levels during floods in Majuli. This tested and emerging technology is a flood-mitigation approach that is adaptable, cost-effective, and can preserve the community integrity of Majuli and other flood-prone areas. Keeping in mind the rich and the diverse architecture of Assam, as well as the economic value of the different materials available for the amphibious type of construction, certain key considerations have been introduced to meet up with the requirements and the demand of the communities in the area.

Therefore, on the basis of the five key guidelines i.e. Floating capacity, Buoyant Foundation, Superstructure, Material services, and Height of the vertical guideposts, several recommendations have been highlighted in the research to develop flood mitigation techniques and methods in the Majuli Island. Primary objective of the study is not to reap away from the natural force of the water but rather it is about developing with the constraints that it poses. Any hindrance in the natural processes contributes to devastating ecological imbalance and hence development with the natural forces should be a priority in our development rather than manipulating the natural forces for our benefit. Investing in an amphibious housing strategy as a flood resilient method can contribute in a similar direction and can also lead to the overall development of the flood-affected areas.

63 | Proposal & Conclusion

Amphibious Structures As A Solution To The Flood-Prone Region Of Majuli Island Assam

REFERENCES i. ii. iii. iv. v. vi.

vii. viii.

ix.

x. xi.

xii.

xiii.

xiv. xv. xvi.

xvii. xviii.

xix.

Anderson Christine, (2014) Amphibious Architecture Living with a rising bay Nelson Nikhila, (2019) Envisaging the scope of amphibious architecture in below sea level regions of Kuttanad T S Adithya and K K Manoj 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1114 012037 Prosun Prithula, (2011) The LIFT House [www] Available from: https://uwspace.uwaterloo.ca/handle/10012/5787 [Accessed 11May2022] Thakur Manish, 2020, Aquatecture: Dwelling units designed to work with water Fennuta Elizabeth (2010) Amphibious Architectures, [www] Available from: https://issuu.com/lizfenuta/docs/amphibious_architectures_thesis/244 [Accessed 5 March 2022] Sarma Alee, (2014) Landscape Degradation of River Island Majuli, Assam (India) due to Flood and Erosion by River Brahmaputra and Its Restoration Formosa, (2014) The Amphibious House, Baca Architects, [www] Available from: https://www.architecturalrecord.com/ext/resources/Issues/2017/April/continuingeducation/Amphibious-House-What-is.pdf [Accessed 119 April 2022] Elizabeth English (2016), Thriving with water: Developments in amphibious architecture in North America [www] Available from: https://www.e3sconferences.org/articles/e3sconf/pdf/2016/02/e3sconf_flood2016_13009.pdf [Accessed 9 March 2022] Champaneri Parth, (2018) Disaster Resilient Houses Baleshwar Singh, (2011) Influence Of Landform And Geomorphic Process On Topographic Evolution Of A River Island [www] Available from: https://www.idconline.com/technical_references/pdfs/civil_engineering/INFLUENCE%20OF.pdf [Accessed 22 April 2022] Siddhartha K. Lahiri, 2014, Morphotectonic evolution of the Majuli Island in the Brahmaputra valley of Assam, India inferred from geomorphic and geophysical analysis Aamirah Salam, (2021) Tales of Traditions, Aspects of Adaptations and Stories of Sustenance of the Largest River Island of the World, [www] Available from: https://www.bibliomed.org/mnsfulltext/218/218-1618166179.pdf?1648208930 [Accessed 2 May 2022] Amal Barman, (2020) IJCRT, Vernacular Architecture of Majuli, [www] Available from: https://ijcrt.org/papers/IJCRT2007175.pdf [Accessed 6 May2022] Waterland: Water Information Network, ‘History of Dutch Water Management 2011, Project Review: Floating Homes, Maasbommel, Netherlands, [www] Available from: https://climate-adapt.eea.europa.eu/metadata/casestudies/amphibious-housing-in-maasbommel-the-netherlands [Accessed 15 April 2022] Urban Green-Blue Grids, Amphibious homes, Maasbommel, Netherlands Resiliency, Case Study, Flood Mitigation, [www] Available from: https://resiliency.lsu.edu/case-study-maasbommel-netherlands [Accessed 6Aprl 2022] Das Mayuri, An assessment of Redistribution of Population in Majuli Island due to river bank erosion [www] Available from: https://iussp.org/sites/default/files/event_call_for_papers/iussp13.pdf [Accesssed 29 April 2022] 64 | Page