“We certify that this piece of work is entirely our own and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged.”
SIGNATURE OF STUDENTS:
(Aditya Tognatta)
DATE:
January 27th, 2017
(Kaushik Sardesai)
ACKNOWLEDGMENTS
Recognising the contributions made by tutors,contemporaries and field experts, without whom this research would not have been possible.
We are extremely grateful to the following people/ organisations for their valuable guidance and contribution in this research.
-Michael Weinstock (Director, AA EmTech)
-George Jeronimidis (Director, AA EmTech)
For their strong commitment and consistent support in helping us gain requisite knowledge, skill and understanding in shaping the entire proposal.
-Evan Greenberg (Studio Master, AA EmTech)
-Elif Erdine (Studio Tutor, AA EmTech)
-Manja van de Worp (Course Tutor, AA EmTech)
For sharing with us their knowledge and expertise in computational skills and scripting tools and for giving us valuable feedback in developing material knowledge and logics.
-Marc Christen (WSL Institute for Snow and Avalanche Research SLF)
-Yves Bühler (WSL Institute for Snow and Avalanche Research SLF)
For sharing with us the most important computational tool for this research (RAMMS: Rapid Mass Movement Simulation) and helping us overcome errors faced in debris flow analysis.
For his invaluable contribution in handling large scale terrain models and environmental modelling inside Grasshopper.
-Patti Stouter (Founder, Simple Earth Structures; mentored by Owen Gieger and Kelly Hart)
-Awais Malik (PhD New York University)
For advising us by their on-ground experience in active earthbag structures and sharing with us research papers and documents for the same.
-Stanzin Chozang (Local Architect, Leh Ladakh)
-Eduardo Paolo Ferrari (M.Arch, Universitá degli Studi di Firenze)
-LAMO (Ladakh Art Media Organisation)
For being an active part of our field survey and providing us with base research documents and drawings pertaining to vernacular Himalayan architecture.
Finally, we would like to express our sincere gratitude to our family and friends for their encouragement and motivation. We would also like to acknowledge the support of all members at the Architectural Association along with our colleagues at the EmTech programme who contributed directly or indirectly to the formation of this project.
ABSTRACT
Emergent resource management strategies for high altitude cold desert biomes.
“Cryic Transformations” is an investigation based on structuring and managing naturally available resources in a cold desert biomes as an emergent method of co-existing with micro-climatic transitions. The work focuses on the high altitude regions of Northern Himalayas; an ecologically sensitive environment prone to incremental climatic change and demographic shifts. Over the past few decades, extreme changes in topography have given rise to multitudinous linear valley settlements, that lack modern technological advancements and are primarily dependent on agricultural and natural water resources for their survival. With specific focus on the seclusion from urban centers and its current evolution as a tourist magnet, this research takes into consideration the rural lifestyle of the inhabitants with the aim of harnessing naturally available commodities that can restore the symmetry in consumption and production.
The project is contextualized in the Leh valley of North India, where accumulative mass flows are rampant and initiate a series of environmental challenges to the rural communities. Mass flows are a resultant of heavy sedimentation, flash floods and glacial lake overflows accelerated by frequent cloudbursts and landslides. This is an immutable process predominant in cold and dry regions prone to heavy precipitation and snowfall. Transportation of material resources to sustain these changes are sporadic and rely entirely on seasonal climatic variations, leading to frequent logistic issues. Further more, the recent shift in occupational patterns from agrarian to tourism and stagnancy in construction styles fails to cope with these land alterations. On site investigations of the social patterns and visual experiences of climatic changes form the primary basis of developing strategies to gain maximum control over the landscape.
The work commences with the translation of statistical information to numerical data sets in order to create a virtual scenario of the actual terrain. Computational algorithms are developed to generate a ten year regressive model that establishes relationships between seasonal changes and topography. Strategies are devised to capitalise on debris flow scenarios to extract earth as a primary building material. Various fabrication techniques are studied and analysed to result in a flexible autonomous earthbag assembly that can be aggregated manually with less material knowledge and automation as compared to vernacular building types.
Resource planning strategies in terms of maximising water distribution and crop productivity in different seasons at various altitudes are developed around the primary model to stabilise local demands and further reduce impacts of periodic soil erosion. Various permutation and combination of these experiments results in a comprehensive landuse pattern that dictates the limit of maximum viable population to be sustained without hampering the production processes.
The research concludes as an integrated proposal that can adapt to future scenarios and establish local control of managing food production, water conservation and material procurement enabling a self-sustaining community spirit that can transform the existing architectural style towards a better growth system.
INTRODUCTION
Life in the Mountains
The Changing Face
Hindu Kush Himalayan Region
Cryic Transformations
DOMAIN
Overview
Understanding cryic landscapes
Building on Slopes
Population shift-Case of Leh
Cryic Architecture
Conclusion
Towards A Resource Driven Settlement
METHODS
Overview
Field Survey
Geo-Spatial Predictive Modeling
Physical Attribute Sampling
Design Methods
Analytical Tools
SITE SYNTHESIS
Overview
Study Patch
System Logic (Mathematical Models)
RUSLE Analysis
Qualitative Analysis
RAMMS Simulation
Risk Map Overlay
Conclusion
RESEARCH DEVELOPMENT
Overview
Weighted Analysis
Modelling Retention Structures
Optimising Positions
Annual Phasing
Adding Dimensions
Wall Sequencing
Wall Statistics
Conclusion
Hydrology
Run-Off Model
Supply V/s Demand
System Logic
Locating Catchments
Increasing Efficiency
Conclusion
Land patterns
Timber Production
Food Production
System Logic
Landuse Patterns
Network Model
Growth Model
Conclusion
DESIGN DEVELOPMENT
Overview
Material Synthesis
Context Study
Integrated Design
DESIGN PROPOSAL
Experiment Sequencing
Morphological Segregation
System Logic
Density Possibilities
Inferences
Aggregation Possibilities
Dwellings
Green Houses
Education
Cold Desert Markets
Conclusions
CONCLUSIONS
DESIGN DETAILS
Overview
Unit Type-01
Unit Type-2
Unit Type-01 Details
Unit Type -02 Details
REFERENCES
APPENDIX
INTRODUCTION
Previous Page Fig| 1.01
A lone Buddhist place of meditation stands amidst the Karakoram Range(Himalayas) showing signs of life and worship. The colored kerchiefs indicate that this place is frequently visited. (Source: Author)
LIFE IN THE MOUNTAINS
An insight into the realm of mountains, describing various socio-economic drivers that expand the need for development in this ecosystem.
The Mountain ecosystem is one of the least known environments in the world, spreading across 23% (approximate) of the global land surface areas. Their height triggers heavy precipitation which, coupled with the water-storing capacity of glaciers, gives them a vital hydrological role– A billion Chinese, Indians and Bangladeshi drink from rivers flowing out of the Himalayas (Raven, 2016).
Almost 35% (1.2 billion) of the total human population dwells in these ecosystems (Fao.org, 2016) within which 47% of the population lives under poverty. Mountain communities have traditionally been isolated due to geographical parameters; developing ecological and social mechanics of sustaining biological development techniques to adapt to a series of environmental eviscerations (water scarcity, low resources , floods) on their own, but have invariably remained poor and at the margins of society. The regions attract a lot of lowlanders, primarily as tourists or as investors in search of mineral rich areas–The Alps accommodate 100 million visitors per year and in the Himalayas, more than 250,000 pilgrims and trekkers. The effects of these migrating transient population manifests in ad-hoc urban developments, stressing the natural resources way beyond its capacity and, now threatens the survival of this unique yet fragile ecosystem.
THE ROCKIES
APPALACHIANS ATLAS ANDES
Height above sea level (in m)
Area (in Km2)
Floods per year
Population (in millions)
Mining activity
Agriculture Activity
Tourist Activity
Following Page : Fig| 1.0 2
The Diagram on the following page represents various mountainous ecosystem in the Northern hemisphere. Comprehensive data comparison indicates that the maximum population density resides in between the following latitudinal band(25oN-45oN). The regions across this band have faced maximum devastation due to floods worldwide.
Current Page (right) : Fig| 01.03
World Projection Map representing the overall temperature change for the year 2080-2100.
(Source: Redrawn from PCC 4th Edition)
Current Page (right) : Fig| 01.04
World Projection Map representing the overall precipitation change for the year 2080-2100. change for the year 2080-2100.
(Source: Redrawn from IPCC 4th Edition)
Next Page: Fig| 01.05
Climatic Projections of the Hindu Kush region, recorded from IPCC.
(Source: Author)
THE CHANGING FACE
Delineating the effects of climate change over high altitude regions as a generic speculation.
Climate change and global temperature rise are unequivocal. With the rise of global temperature (1.5-4.5) by the end of the 21st century, global glacier volume is expected to decrease by 35-85% (IPCC AR5,2014). In all likelihood, the effects of climate change will become evident in these cryic regions first and with the greatest intensity. An increase in the floods has been seen in the past decade, where mountainous regions are being affected at a comparatively higher rate than most of the other ecosystems.
Hindu kush– the most densely populated trans-boundary mountain ecosystem has been suffering periodic losses, affecting nearly a 100 million people (EM.DAT, 2016). And now these mountainous ecosystems face a massive test of their robustness from projected climate change and anthropogenic factors.
The four major aspects governing development in this ecosystem are: Increase in population, migration and tourism (infrastructure demand), Availability of resources (water and food), climatic changes (causing floods and other aberrations), material sourcing (remotely located areas). The synergy between these natural and human systems area under stress due to climate changes and globalization; resulting in climatic aberrations. Short winter months incur low snowfall in the region, thus unable to replenish the ice reserves, increasing water scarcity. Due to which a decline has been seen in the agricultural production in the mountain regions (ICIMOD, 2011). Rampant ad-hoc urbanization due to tourism disregardful of any understanding of planning, local mitigation techniques, energy consumption or ecology, affects drainage layouts and hydrology of the site. Indigenous resilient methods are now in need of an upgrade as the are failing to cope with these climatic changes.
Amidst all the uncertainties these areas are thriving tourist community that provide a significant revenue to these autonomous mountain regions. These regions provide a unique opportunity to harness these climatic aberrations and utilize them advantageously through an in-depth understanding of the indigenous systems that have been developed over many millennia’s.
AFGHANISTAN
brahmaputra
PAKISTAN
irrawaddy salween mekong yangtese yellow river
BAY OF BENGAL
ARABIAN SEA
BHUTAN
BANGLADESH
MYANMAR
01-3
HINDU KUSH HIMALAYAN REGION (HKH)
Previous Page (Centre) : Fig| 01.06 Projection map of Asian subcontinent depicting the extents of Hindu kush region along with various rivers,namely: Indus. Bhramaputra, ganges, Yangtest, Yellow river, Mekong, Amu and Irrawaddy.
Source:: redrawn from ICIMOD,2010)
Current Page (right) Fig| 01.07
The following images represent different aspects of high altitude settlements, depicting lifestyle and architecture.
Hindu Kush Himalayan region is a high altitude mountain ecosystem with an expanse of 3,441,719 Sq.km; spreading across eight countries (Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, and Pakistan). Home to about 600 million people it is the most densely populated mountain ecosystem in the world (Icimod.org, 2016). Situated within the Latitudinal band (300 N) , helps it support a multitude of climatic variations along its slopes. Supporting more than 2500 different species of flora and fauna, making it the most diverse and vibrant ecosystem amongst the all the mountain ecosystem within the latitudinal band. The first trace of humans is dated to be as old as 21000 years ago (RT International, 2016) a testament of the peculiar evolutionary path taken bu humans, plants, and animals to survive in the dizzying altitudes of the Himalayas.
RESOURCE DEPLETION
The Himalayan mountain region has predominantly remained poor as compared to the urban mainlands thus relying mostly on natural resources rather than packaged goods. Also due to remote location, coupled with nomadic way of living these settlements have limited development facilities from their respective governments, which is nearly common across the Hindu Kush region. Although certain towns such as Leh have boomed into tourist destination, the rampant urbanistation is taking a toll on the already scarce natural resources; overuse of ground water and frequent logging activities pose serious ecological and logistical repercussions.
An Insight into the most diverse cryic region of the world
LOWER HIMALAYAS
MIDDLE HIMALAYAS
EXPANSE & BORDERS
01-3.3
CLIMATE & DEMOGRAPHICS
01-3.4
The Hindu Kush is a 3500- kilometer long (Icimod.org, 2016) mountain range that stretches between central Afghanistan in the west to the eastern borders of China in the east. Made up of three parallel ranges : Lesser Himalayas, Middle Himalayas and Greater Himalayas, it covers a total land area of 3,500 sqkm is spreading in across eight countries. Fig 1.08 shows the area distribution of the Hindu Kush Himalayan region.
The Himalayan Alpine climate varies according to the elevation. It gets colder as the elevation increases and gets wetter as the elevation drops. As a result, the temperature and climatic changes in the Himalayan regions change very quickly (Indianetzone.com, 2017). The two major seasons of the Himalayan region are winter and summer (Travel-himalayas.com, 2017). Usually throughout the year the Alpine-Himalayan region receives continuous snowfall. The Lesser Himalayas (Refer Fig|1.08) experience a peak temperature of 35 degrees celsius during summers, while the average winter temperature is 10 degree celsius. While in the middle and higher Himalayas the summer temperature which is being recorded ranges from 15 to 18 degree Celsius, the winters are found to be below the freezing point. The greater Himalayas are snow covered through the year.
Beyond the greater Himalayas lies the Trans-Himalayan region that has a cold desert climate, as it lies in the rain-shadow region. Although, these areas are now facing erratic monsoon and snow patterns, due to global warming and anthropogenic transformations. The Himalayas are diverse in people, climate, ecology, soil, flora & fauna. The population is scattered and usually increases with the decrease in altitude. In the higher altitudes, the population is widely scattered and are generally seen in valleys along streams or glacial streams or near river-wetlands
TERAI
SHIVALIKS
HIGHER HIMALAYAS
TIBETAN PLATEAU
Previous Page Fig| 01.08 Diagram showing various attitudinal zones.
(Source: Redrawn from http:// archive.unu.edu/unupress/unupbooks/80a02e/80A02E00.gif)
Current Page (right) Fig| 01.09 Picture showing melting of glacier in Alsakan valley.
MOUNTAINS IN PERIL The Hindu Kush (HKH) region is undergoing rapid, dramatic changes triggered largely by the economic growth. Globalisation and increased mobility have exacerbated the marginality of the mountain valleys while creating new opportunities; transforming the region into a thriving tourism industry while stressing the natural resources to the utmost limits(ICIMOD,2010).
The 54,000 glaciers spread across 6,000 sq-km of HKH region that provides water to nearly 210 billion people (ICIMOD,2010) are receding at an alarming rate; transforming the hydrological flows, causing floods and droughts across the region. Climate anomalies caused due to global warming (due to black carbon deposition in the troposphere) is increasing the duration summer hot days and declining snow cover cold days in the region.
Future temperature increases are expected to be stronger over land than over the ocean, stronger at the high altitude than in the tropics; the global warm will increase by 1.5- 4.5 Celsius by 20852100 (IPCC, 5th Assessment). In all likelihood, the effects of climate change will become evident here first and with the greatest intensity (Singh, 2011). Already an increase in the annual precipitation has been recorded throughout the region, leading to flash floods in Western (ICIMOD,2010) The situation is compounded by the fact that the mountains in the region store vast quantities of water in the form of snow and ice, which is all part of the regional monsoon circulation patterns. The central role of the monsoon as the lifeline of regional agriculture may be changing and calls for an in-depth understanding of this unique ecosystem (ICIMOD,2010).
Responsive architectural strategies and potential opportunities within the parameters of the region .
The primary drivers that define the growth and maturity of informal settlements in cryic regions are climate change and rapid globalisation. This effect is being realised by incremental depletion of natural resources through anthropogenic activities. The local communities depend largely on mountain resources for their livelihood which is predominantly agriculture and cattle rearing. Another alternative source, a more popular one is tourism, drives the local economy to a great extent, however, accelerates resource harnessing and depletion.
The informal settlements, being in the same climatic zone and terrain are largely stereotypical and thrive mainly on two principles: 1) build on flat land 2) build near water. These principles pose different values for different population densities and this differentiation combined with environmental changes leads to unplanned development and insensitivity.
The stagnancy in architectural growth due to limited knowledge and resources has opened new opportunities for transforming the current state of these stereotypic settlements. The culmination of technological advancements, computational tools and techniques with locally sourced materials and construction can yield potentially inhabitable outputs which can be dynamic and sustainable to withstand the pressures of environmental changes and demography.
02-1
OVERVIEW
An overview of the knowledge passed on for generations, unique to high altitude settlements.
PRIMARY FOCUS
02-1.1
Adaptability and resilience being the primary factors for survival and progression, define and complement the architectural output and typology in high altitude settlements. The fragility of the Eco-system and climatic extremes has set default thumb-rules that outline the basis of design and aggregation. Optimisation of each unit is highly dependent on the context, positioning, and orientation and can differentiate radically from its neighbour. However, a noticeable pattern between these dwellings can be observed mainly due to common risk factors and global climate change.
PRIMARY FOCUS
02-1.2
PRIMARY FOCUS
02-1.3
The following sections address the issues and responses about the challenges faced by these cryic regions, such as rapid mass movements, food and water deficit and soil loss. A single local unit to a regional architectural scale and recent design proposals that widen the scope of experimentation have been explored; drawing parallels from many indigenous and contemporary references across the Himalayan terrain.
This research outlines the high altitude regions of the Himalayas, specifically the Indian extents, mainly due to the presence of several stereotypical settlements and immense population outburst. The parameters that define the context are variable in different domains. However, the attempt is to understand the synergy between the architecture and surrounding environment.
An overview of the various challenges experienced by linear valley settlements, during construction.
PRIMARY FOCUS DOMAIN STRUCTURE
“Every form in Nature is essentially the product of the diagram of forces acting on it or which have acted on it”(D’Arcy,1945). Present built structures constructed by all living beings exhibit the same phenomenon (Not cities but community living in peculiar ecosystem, such as mountains, Tundra etc), because over time, its tessellation grows an intrinsic relationship with the ecosystem and its natural flows. Thus understanding this cold-desert type ecosystem and the natural forces acting in the region is of paramount importance to illustrate the relationship between architecture and surrounding ecology.
These phenomenons have been stratified into four categories. Staring from soil and terrain– The uneven landscapes comprising of mountains and valleys, often covered in steep talus formations along with scree depositions on the foothills (where inhabitants usually build) is the primary cause of foundation failures. This loose strata is under constant weathering due to freeze and thaw mechanism; breaking the top strata further into smaller rocks or sand. Hydrological flows from rapid snow melt (RSM) and cloud bursts, results in serious consequences, as the impermeable soil ( lacking any organic matter and vegetation), promotes surface run-off, which is further intensified due to terrain and causes heave of foundations. The high thermal mass materials (sun-dried bricks) used for construction as they are locally available, are often washed away due to these flows. While the harsh climate and geographical position challenges procurement of construction material, machinery and skilled labor is extremely expensive.
Current Page (right): Fig| 02.1
A view of the washed off buildings area near Kedarnath Dham in Uttarakhand damaged by flash floods in 2010.
Current Page (below): Fig| 02.2 Graphic showing the scale of linear settlements with respect to terrain.
(Source: Image redrawn computationally through image sampling technique from Google earth)
MASS WASTING
Since most of the settlements have evolved around valleys and river banks, mass movement due to land disintegration from higher altitudes plays a crucial role in the sustenance of these settlements.
MITIGATION TECHNIQUES
Various mitigation techniques of slope stabilisation and controlling debris flow have been implemented which lack adequate maintenance, financial backing and communal participation.
The delay in material procurement due to harsh terrain and climatic conditions has led to a major material shift in building typology which is unsuitable mainly due to lack of automation and machinery. 02-2a 02-2c
RESOURCE ECONOMICS
Increased migration activity into linear valley settlements has put adequate pressure on primary commodities like food and water. The shift in occupation from agrarian to tourism has further affected the rate of production versus consumption.
MATERIAL LOGISTICS
MASS WASTING
Defining the domain of mass wasting within the context of this research.
TERRAIN DYNAMICS
Steep mountain slopes undergo constant weathering and destabilisation (due to erosion, floods, and snow-melt) giving rise to mass wasting– Movement of rocks and regolith along the slopes of mountains (Refer Fig| 02.8). The driving force behind this wasting is usually gravity, although the cause may vary from regular erosion to cloudbursts; causing damage to life and infrastructure built at the base of slopes. These gravitational flows occur incessantly in the Hindu Kush regions, causing damage to life and structures.
The HKH areas with its differential in heights (1000m- 8000m a.s.l) and variable water run-off and soil properties dictates the outcome of such events. Saturated soil conditions preventing water absorption, is the primary cause of slides and flow in these autonomous hilly regions of the Himalayas. Debris flow is the most frequent of gravity flow which occurs on a regular basis, bringing down with them loose rocks and boulders along heavy quantity of loose strata; completely transforming landscapes through uneven deposition and by disturbing drainage patterns. Since debris flow can be gradual to rampant in velocities (Refer graph Fig|02.4), it becomes extremely vital to understand the parameters that can help predict debris flow dynamics. Thus further exploration into soil and terrain based parameters were carried out, the understanding generated from this study would help develop a digital debris flow model.
02-2.2
SOIL DYNAMICS
A periodic phenomenon peculiar to cryic regions; aggravated by sudden weather changes.
Previous Page (top): Fig| 02.3
Flow diagram showing the sequential stratification of various flows as per soil texture type.
(Source: delineated from various geological sources by Author)
Previous Page (below) Fig| 02.4
Graph plotting various flows in-accordance to their velocities and flow type
(Source: re-interpreted from http://www.iitbhu. ac.in/faculty/min/rajesh-rai/NMEICT-Slope/ lecture/c10/l11_files/image006.jpg)
Current Page (top): Fig| 02.5 Diagram showing the threshold of landslip and rockfall on sloped gradients.
(Source: from Author)
Lateral Distance
SOIL STRUCTURE
Sand fraction in soils of these region is found increasing along the altitude, whereas silt fraction is in reverse order indicating the dominance of sand forming minerals in parent materials (Charan et al., 2013). Hence, these soils are dominated by sand, alike the hot arid soils, and are classified as Sandy loam textural soils (Charan et al., 2013). These soils have are known for low infiltration capacity thus the tendency to get saturated even after snow melt is relatively high, resulting in destabilization or landslides. The causes of landslides are generally separated into two types: “Preparatory” factors which work to make the slope increasingly susceptible to failure without actually initiating it, and “Triggering“ factors that initiate movement (like rainfall, snow melt etc). The susceptibility of a particular hillside to failure is expressed as a “ Factor of Safety”. For any potential failure surface, there is a balance between the weight of the potential landslide ( driving force or shear force) and the inherent strength of the soil or rock within the hillside ( shear resistance). Provided the available shear resistance is greater than the shear force then the Factor of Safety will be greater than 1.0 and the slope will remain stable. If the Factor of Safety reduces to less than 1.0 through some change in conditions, the model predicts failure. The above study indicates as sand content in soil increases with altitude, where susceptibility to slides increases, thus indicating towards soil texture mapping for generating possible risk maps for land slide susceptibility.
Initial Stage Fig| 02.6 Steep angle of repose indicating high risk of further erosion.
Intermediate Stage Fig| 02.7
Debris droppings become more frequent, burrying the house slowly..
Current page (top): Fig| 02.9
Slump across a road in Afghanistan, destroying settlements below.
Diagram depicting the initiation and culmination points of a slide.
(Source: Author)
DEBRIS FLOW
Understanding the impact of debris flow on the surface in relation to height, velocity and time.
DEBRIS FLOW
02-2.3.1
After exploring the effect of sand and soil texture along with various triggering factors of Debris flows, it was necessary to understand the dynamics of debris flow, as a typical debris flows usually comprises a mixture of fine (clay, silt and sand) and coarse (gravel, cobbles and boulders) materials with a variable quantity of water. The resulting mixtures often behave like viscous “slurries” as they flow down slope. They are often of high density, 60% to 80% by weight solids (Varnes, 1978; Hutchinson, 1988), and may be described as being analogous to “wet concrete” (Hutchinson, 1988)
FLOW DYNAMICS
02-2.3.2
Hillside debris flows typically start as a sliding detachment of material (upland debris slide, peat slide, rock slide etc.), usually initiated during heavy rainfall, which subsequently breaks down into a disaggregated mass in which shear surfaces are short-lived and usually not preserved. The failure mass usually combines with surface water flow, which typically results in high mobility and run-out. Ultimately, landslides occur when the force of gravity exceeds the strength of soils and rocks forming slopes,. Thus vegetation or some sort of anchoring of soil is required to generate friction between particles that would not allow for sliding /overturning. In such circumstances, slope failure occurs to restore the balance between the destabilising forces (stresses) and the resisting forces (shear strength) along the surface of rupture or shear surface. Therefore, a landslide may be regarded as a dynamic process that changes a slope from an unstable to a more stable state. This meant that when debris are in momentum they become hard to mitigate, indicating towards a layered defensive and directing mechanism.
Current Page (top): Fig| 02.11
Image showing the destruction in Sabo village during debris flow of 2010. (Source http://static.indianexpress.com/m-images/M_Id_167206_Leh_disaster.jpg)
Current Page (bottom): Fig| 02.12
Diagram depicting change in depth of foundations with slope angles. (Source: Author)
02-2.4
BUILDING ON SLOPES
Understanding the impact of debris flow on the surface in relation to height, velocity and time.
Hindu Kush high altitude plateau has widespread earth consisting of rocks, pebbles, silt, loam and various other varieties of soil depending upon the locations. Soils of high altitude cold desert originate from weathered rocks; largely immature in texture with large proportion of sand gravel and stone in them. The higher elevations are cut by channels of glacial rivers, that bring down fluvial flows with rocks and debris; the terrain is uneven with narrow and steep “V-shaped” valleys in the lower regions these rivers widen the valleys, further depositing loose rocks and debris transforming terrain into “U-shaped” valleys. The steeper valleys are comparatively less populated as compared to the “U-shaped” valleys in these regions, the former “types” are subjected to higher altitudes with low atmospheric oxygen long with unstable terrain with high erosion rates. Due to these patterns the valleys are constantly hit by landslides and mass flows (Refer Fig2.11). Thus, alternating scenarios for occupying slopes and not just the valleys should be explored as future growth possibilities.
FOUNDATIONS
Abundant in natural resources and fluvial sediments these valleys become the most viable spots for sustaining life; many settlements thrive in these biomes, with architectonics unique to its surroundings. Deeper stone foundations are seen on steep slopes that arise from leveled land, just below the surface, whereas shallow stone foundations are seen on relatively less steep slopes (Refer Fig2.12). Rock-cut/ cave Architecture has always been prevalent in these regions, but have been limited only to construction of monasteries and houses for monks.
02-2.5
MITIGATION TECHNIQUES
An overview of the techniques adopted to mitigate erosion and flow in regions of slope extremes, with specific focus on the region of Leh-Ladakh.
MITIGATION TECHNIQUES
Previous Page (top): Fig| 02.13Image Diagram depicting the various techniques used for slope stabilisation and water managements on steep slopes.
(Source Author)
Current Page (top): Fig| 02.14 Diagram showing the working principles of an artificial glacier
(Source: Author)
Terracing
Diversion channels
Drop structures
Retaining walls
Grassed waterways
Conservation Ponds
Sabo dams
Gully control
Artificial Glaciers
Bamboo fencing
Bush layering
Bush mattress’
Fiberschine
Jute netting
Live Crib-wall
Palisades
Live fascines
Wattle fence
TECHNIQUES Ladakh being a cold-dry high altitude plateau has harsh terrain with sandy loam soil, which is poor in absorbing water resulting in de-stabilized slopes leading to rock fall and mass flow (combined with hydrological flows). Both physical and bio-engineering practices have been adopted to stabilize these slopes, some of these techniques are millenia’s old but have been re-interpreted to adhere to the current climatic alterations.
BIO- ENGINEERING
PHYSICAL METHODS
Bio Engineering techniques are a combination of engineering principles applied to (or with) living systems. In terms of flash flood mitigation, it refers to a combination of biological, mechanical and ecological concepts to reduce soil erosion, stabilise soil and protect soil, using vegetation or a combination of vegetation and construction materials (ICIMOD,2012)
Bio engineering methods being both cost effective and easy to install are often not sufficient to deal with debris flow (during mass failure) and are not appropriate to address all interventions to reduce flash flood risk, thus physical structures / systems are required (ICIMOD,2012). Various construction types are used to retain soil and prevent soil erosion. These types are chosen based upon the site conditions and the required resultant.
02-2.6
ARTIFICIAL GLACIERS
A recent method of regulating water shortage by harnessing wasted glacial melt water during winters
PRINCIPAL
ORIENTATION
Artificial glaciers works on the principal of collecting and storing glacial melt-water, while exploiting gravity and freezing winter temperatures.
The orientation of the system is the most vital parameter that governs its overall success. A site that is North-facing and usually under-shade is chosen for constructing this system. It is usually placed between the glacier and the village such that the proximity of the artificial glacier is < 1Km. So that the melt water can be used instantaneously during summers /planting season (Norphel,2012)
PARAMETERS
The schematics of this system can be classified into the following: diverting, silting, retaining and distribution. Diversion of natural glacial flow is diverted using water channels that double up as silting tanks (segregating small stones and debris. These channels usually have a gradient of 1:50. Then the melt -water is transported through into a distribution chamber, controlled by gates and into many retaining pools. Here the gradient is very less as the water needs to be slowed down in-order to freeze. Then the gates are opened again during summers to allow melt water to flow back into the village.
02-2.5a
PHYSICAL TECHNIQUES
An overview of the techniques adopted to mitigate erosion and flow in regions of slope extremes.
TERRACING
02-2.5a.1
A technique that converts slopes into horizontal stepped surface, which prevents water run-off and sediment flows. The terrace edges are usually planted with trees, small plants and grass on the outward facing edge to increase stability (ICIMOD,2015). There are three main types of terraces: Bench, level and parallel that are constructed depending upon the soil conditions, intended result and slope gradient with a aim of:
-Control the flow of surface runoff conveying it to an outlet at non-erosive velocity.
-Reducing soil erosion by trapping the soil on the terrace. -Creating flat land suitable for cultivation.
EMBANKMENT PONDS
02-2.5a.2
These are small ponds also known as farm ponds, they are usually constructed for the purpose of storing water from surface run-off. These ponds help in peak flow reduction and surface erosion during excessive rainfall, thus reducing the risk of floods, they also provide supplemental irrigation for agriculture and water for domestic purposes. Conservation ponds play an important role in areas that are river fed (ICIMOD,2015). These ponds can be broadly divided into dugout ponds and embankment ponds.
RETAINING WALLS
02-2.5a.3
Artificial structures that has the capability of retaining back soil, rock or water in order to safeguard a structure, building or area. These walls prevent soil erosion and downward movement of mass flows while providing support for vertical or near vertical changes in slope gradient. The walls are generally made from timber , masonry, stone, brick , concrete, vinyl,steel or a combination of these, depending upon site conditions and resultant required. Retaining walls acts to support the lateral pressure exerted by a soil mass that causes slope failure. These walls can be stratified into five different types: Gravity, Semi Gravity, Cantilever, Counter-for and Buttressed retaining walls (ICIMOD,2015)
Fig| 02.15I (Source: ICIMOD,2010)
Fig| 02.16I (Source: ICIMOD,2010)
Fig| 02.17I (Source: ICIMOD,2010)
DROP STRUCTURES
02-2.5a.4
Also known as grade control structures, are placed at intervals along a channel reach to transform a continuous slope into a series of gentle slopes and vertical drops. These structures help in preventing soil erosion and river channel degradation by reducing the erosive velocity of water. They also help to control flooding by trapping the sediment moving with the runoff water. Drop structures include sills, weirs, chute spillways, drop pipes and check dams. In steep hill and mountainous regions the most common drop structures are check dams, often used to control gully erosion. These structures can be made of concrete, timber, sloping rapier sills and soil-cement or gabions (ICIMOD,2015).
SABO DAMS
02-2.5a.5
These structures are a common measure to limit debris flow. The word “sabo” is of Japanese origin meaning soil conservation (sa- soil, bo-conservation). Sabo dams are relatively small structures built across the bed i upstream areas in the form of a dike. They have a lower “open” section at the center which allows the debris to pass through during normal conditions but prevent large-scale debris flow during flash floods. Sabo dams accumulate sediment and suppress the production and flow of sediment. They are also built at the exit of the valleys, working as a direct barrier to a debris flow. These dams are usually constructed using masonry, concrete, reinforced concrete, or steel cribs according to site conditions (ICIMOD,2015)
GULLY CONTROL
02-2.5a.6
Gullies are highly visible form of soil erosion created by running water. They are deep-sided water courses gouged out by surface water flow. Water flow is concentrated down the rills , leading to increased erosion and eventually formation of a full gully. These channels accelerate surface runoff and contribute to flash flood development, as well as causing damage to the surrounding area and infrastructure, reducing the productivity of farmlands and contributing to sediment flow and sedimentation of downstream lands, streams , channels and reservoirs(DSCWM,2004). These gully’s can be controlled through catchment are improvement, gully head stabilization and diversion of surface water through check dams (ICIMOD,2015).
Fig| 02.18I (Source: ICIMOD,2010)
Fig| 02.19I (Source: ICIMOD,2010)
Fig| 02.20I (Source: ICIMOD,2010)
02-2.5b
BIO-ENGINEERING TECHNIQUES
An overview of the techniques adopted to mitigate erosion and flow in regions of slope extremes.
BAMBOO FENCING
02-2.5b.1
Bamboo fencing can be used to prevent soil creep or surface erosion on a slope, to hinder gully erosion, particularly in seasonal water channels, and to control flood waves along a river bank. Live bamboo pegs can be used for the main posts so that the whole structure becomes rooted. The growing bamboo can be further interleaved between the posts to increase the strength of the fence. Shrubs and grasses are planted on the upper side of the fence to hold small particles. The main purpose is to trap loose sediments on the slope, to improve the conditions for growing vegetation, and to reduce the surface runoff rate (ICIMOD,2015).
BRANCH LAYERING
02-2.5b.2
In this system. live cut branches are interspersed between layers of soil to stabilise a slope against shallow sliding or erosion. Fresh green cuttings are layered in line across the slope. The root depths anchor and reinforce the upper soil layers (upto 2m depth) and the foliage helps to trap debris (Howell 1999, cited in Lammeranner et al. 2005). Some toe protection structures such as wattle fencing, fiberschine, or rock rip rap may be required to support brush layering (ICIMOD,2015).
JUTE NETTING
02-2.5b.3
Jute Netting is a useful way of stabilizing steep slopes of 35-800 where it is difficult to establish vegetation. Locally available woven jute net is used as a form of armour on the slope and low growing grass is planted through the holes. The technique is often used in South Asia to reduce landslides along roads. The aim is to protect the bare slope from rain splash erosion, to improve the condition of the site and to enable vegetation to become established by retaining soil moisture and increasing infiltration.
Fig| 02.21I (Source: ICIMOD,2010)
Fig| 02.22I (Source: ICIMOD,2010)
Fig| 02.23I (Source: ICIMOD,2010)
LIVE CRIB WALL
02-2.5b.4
A crib wall is a box structure made of interlocking struts and back filled boulders, soil or similar. They are mainly used to stabilise steep banks and protect them against undercutting. However, they are only effective where the volume of soil to be stabilised in relatively small. Crib walls should be installed at an angle of 10 - 150 towards the slope to increase stability. Green willow branches can be used to ensure a quick outcome. Vegetated crib walls provide immediate protection, and their effectiveness increases over the time as the vegetation grows. Once the plants become established, the vegetation gradually takes over the structural functions of the wooden supports (Gray and Sotir 1996 cited in Lammeranner et al. 2005)
WATTLE FENCE
02-2.5b.5
A wattle fence is made by weaving flexible branches or vines between posts, rather like a large basket. A live wattle fence is constructed out of live branches which will root and continue to grow and strengthen the fence. The main purpose of wattle fences is to catch debris moving down a slope and to reinforce and modify the slope. The main purpose of wattle fences is to catch debris moving down a slope and to reinforce and modify the slope. Different kinds of grass and tree species can also be planted along the fence. Wattle fences are useful in small shallow short slides as well as for river bank protection if combined with other measures such as brush layering, live pegs and rock riprap.
BUSH MATTRESS
02-2.5b.6
A brush mattress is a layer of interlaced live branches placed on a bank face or slope, often with a live fascine and/ or rock at the base . The objective is to provide a live protective covering to an eroding bank to hinder erosion, to reduce the river velocity along the bank, and to accumulate the sediment. The mattress is generally constructed from live stakes, fascines and branches from species that root easily to provide immediate effective protection. A layer of bio degradable material such as loosely woven jute can be placed under the mat on steep slopes to increase stability if the soil is very loose. The mattress that is formed protects the surface of the bank until the branches can root and native vegetation becomes established (ICIMOD,2015)
Fig| 02.24I (Source: ICIMOD,2010)
Fig| 02.25I (Source: ICIMOD,2010)
Fig| 02.26I (Source: ICIMOD,2010)
The outburst from early 1970’s transformed the face of Leh to an extent where the tourist population exceeds the local population by nearly 70 %. From 527 tourists in 1974, the latest census suggests that the annual inflow is 50,000 people with a daily transience of 135 people.
Leh was particularly well established in providing services to the Indian Army on their way to disputed border regions, however, the current focus shifted more towards sustaining tourist population.
Current Page (top): Fig| 02.27 Image showing the valley of leh during the summer of 2003,d depicting low population in the region (Source From Author)
Current Page (bottom): Fig| 02.28 Diagram showing the working principles of an artificial glacier (Source: From Author)
POPULATION SHIFT: THE CASE OF LEH
Impact of seasonal tourism and annual migration on the terrain and ecology of the region.
Despite legislative control and climatic constraints, the highland settlements strive to stabilize incremental activities of tourism and migration. The influx being largely seasonal and perdurable has led to the rapid construction of hotels, guest-houses and adaptive reuse of singular units. A typical unit in these regions provides immense flexibility to modify the internal spatial function in order to accommodate more people. The lower floor that was initially developed for cattle and manure can be refurbished to hold an additional family or house a small cafeteria. The space on the upper floor is compromised by combining the kitchenette and living room into one, and excluding the prayer room to provide additional floor area for local residents. The terraces are developed as community space due to limited seating capacity for the cafe.
The gradual reconfiguration of multiple households for monetary gains has reduced cattle inhabitation and population. This has had a significant impact on sustaining circadian activities in the winter when tourism is relatively low and a majority of the local population needs to depend on cattle rearing and agriculture inevitably.
The mountain ecosystem defines the heterogeneity of visitors from religion to research, architecture and recreation. The incremental influx of people into this fragile environment affects the infrastructural stability and maintenance. Due to the limited availability of buildable land, community-based tourism is restrained to very few areas in the region. This, in turn, increases the occupancy pressure leading to the conversion of private units to guest-houses. Resource management in conjunction with other issues of maintaining a balance between supply and demand lacks additional speculation. The transition from singular household activity to multiple uses of resources per unit collectively consumes twice the energy. The differential output in energy consumption thereby demands an alternative source that can couple with the traditional production.
02-3.1
RESOURCE ECONOMICS
The challenge faced in resource management due to increasing population growth and migration.
Current Page: Fig| 02.31
People of leh line-up in queue to monitored supply of fresh water for daily needs.
Image depicts the mechanised logging activites to ensure the increased demands of population. (Source: http://purewatermovement.org/wp-content/uploads/2015/09/4684039424_c1861d55d4_b-e1432593084566.jpg)
DISTRIBUTION FREQUENCY
The distribution patterns are strictly on need-based, as any journey in an around these regions is highly resource intensive. As these areas are now experiencing a massive shift towards unplanned urbanisation and tourist towns are developing up everywhere. This transformation is having adverse effects in the valleys. Self-sufficient villages that would produce its own food and store water are now relied heavily on import as the consumption due to transient population has increased. The Major Hub for all imports is Leh, as it has the only functioning Airport at 4000m ASL. While food and water are locally distributed between village through roads. Construction material is mainly obtained from the nearby Kashmir valley. The Army completely dominated the lands as they distribute petrol and other supplementary army rations, especially during winters since all routes are frozen and the valley is under complete isolation.
The shift from farmlands and local handicrafts to commercial transport business and property lettings has subsequently increased the demand of attaining valuable natural resources. While agricultural practices continue to decline, the region faces acute water shortages in winter due to rapid freezing of ground water and local pipelines. Timber being the primary building material is procured at an accelerated rate to support the growing need of infrastructural development. The large scale clearance increases the surface run-off leading to rapid mass movement along the steep Himalayan slopes. Perhaps the only factor that enhances the depletion of resources is the local shift of household patterns from single family units to multi level lodging, that becomes necessary for economic and monetary gains.
Current Page: Fig| 02.33 Diagram showing the primary and secondary water stream along with attachments distribution in the Leh town.
(Source: (Khan, 2013))
02-3.2
HYDROLOGICAL CONSUMPTION
Decreasing water supply due to rapid urbanisation and extreme climatic changes.
Fig| 2.33 Water Supply and Distribution in Leh Town
Ever since the outburst of tourist population, one of Leh’s potential priorities has been water procurement and conservation. Apart from packaged drinking water being imported into the region, water conservation is implemented primarily through artificial glaciers and snow precipitation. The combined outcome moderately supports the agricultural production but fails to sustain the demand of regular water usage. The dogmatic shift from using stone to mud bricks for faster construction has led to enhanced water loss due to the porosity and higher coefficient of absorption. There has been no official record of the ground water table in Leh, which makes it a growing concern to conserve water resources. However, the supply is divided into three autonomous systems; agriculture, army and resident that monitor and manage the rate of usage.
The agricultural sector depends 100% on canal irrigation sourced from the upper mountain glaciers. However, the system proves to be ineffective due to the slow melting process caused by latent heat and naturally long winding stream path that delays the flow reaching out the downstream areas. The potable water supply managed by the PHE (Public Health & Engineering Department) sources water from springs and groundwater through on-site taps, water tankers and public stand posts. The performance of this system is reduced to zero in winters due to ground frost and frozen water pipes. Maximum water supplied is wasted due to inadequate, unplanned drainage system. The density of people per hour around the public posts and the stronghold of army and tourists results in complete deficiency of water resources.
02-3.3
AGRICULTURAL PRODUCTIVITY
The challenge faced in resource management due to increasing population.
Area allotment for crops
The difference in personal economic growth from agriculture as opposed to tourism is considered to be almost negligible by the locals. Agriculture has thus been on the decline due to conversion of arable land into commercial and residential areas. The Department of Agriculture has initiated various programs to maintain the production by giving 50% subsidies to machinery and infrastructural setup.
The lack of response from the locals is primarily due to mediocre water supply in winter and higher rate of evapo-transpiration in summer. The rate of evapo-transpiration directly affects the cell growth of the vegetation. Thus in order to achieve the best natural growth of any crop, the water resources should be in closer proximity to the fields, or nearly equal to the rate of evapo-transpiration.
Leh has extreme elevation differences over short distances that directly affect the crop calender, leading to diverse cultivation practices. The economical shift from barter to monetized marketing has also impacted the change of cultivation patterns. Farming of exotic vegetables along with traditional cereal crops demands additional water supply. The water allocation system in Leh does not correspond to the spatial organization of crop water requirements thus leading to compromised annual production.
Fig| 2.34 Agricultural and forest distribution in Leh Town
Current Page: Fig| 02.34
Diagram showing the spread of agriculture and groves across Leh .. (Source: (Khan, 2013)
MATERIAL
LOGISTICS
Assessment of transportation systems of material supply into the region.
DELAYED PROCUREMENT
02-3.4.1
Extreme isolation, harsh terrain and weather, results in a dearth of transport infrastructure in these regions. One single road, National Highway 01 (Refer Fig 2.35) is currently the only vehicular road that connects the Ladakh valley to the state of Jammu and Kashmir. Maintained by the military and the locals as a combined effort to maintain a steady supply of resources both inbound and outbound from the valley. The highway is treacherous as it passes through steep hills which are frequently hit by landslides; accidents are common and a daily affair on these roads. Being the cheapest way to travel into these valleys, it is often the busiest during the summers as thousands of truck and machinery are towed to these areas to support the villages. And to repair the damaged/ dilapidated infrastructure that occurred during harsh winters is a very daunting task for the local authorities as the roads are frozen with 4-7m thick ice. During these months (Oct-Mar) the valley is completely isolated from the world outside.
INDIA
Previous Page(top): Fig| 02.35 Map.pf India showing the roads leading into Leh-ladakh
(Source: Author)
Current Page(top): Fig| 02.36
A heavy loader lies displaced due to uneven terrain while traversing through NH-01, to Leh.
A Plane is seen landing on the army airport in leh.Its the only airport in Ladakh (Source: https://tourity.com/uploads/iti/px/149_ Leh_Airport_plan_landing.jpg).
Terrestrial transportation primarily is conducted through small to medium trucks (primarily box type) capable of carrying large loads over high terrain. Heavy trucks are restricted to certain sections of the road width in the hills is not sufficient. Being the only way to travel to in winters (if the roads have been cleared of the snow), it is also the cheapest. Even the Army utilizes the roads to replenish their supplies and upgrade armory and equipments in various posts spread around the valley. However, the winding roads particularly narrow in width and up-slope conditions severely delays the material supply into the region. Perishable goods incur major losses due to periodic delays , thereby leading to increased reduction of supply.
Being a highly militarized zone all the three Airports are run and managed by the Army and are mainly used for Army goods and supplies. Domestic aircrafts also land on these Airports that carry tourists and import goods for the locals. These Airports are barely functional during the winters due to disruptive wind conditions in the valley. Also the lack of man power to clear the run-way from snow disrupts flight patterns in the area. Considering it being the fastest way to enter the Ladakh valley, it is also the most expensive. Prioritising demands between local requirements and armed forces thereby proves crucial and lacks in-depth attention.
Analysis of settlement patterns and building typologies in the cold desert regions of Northern Himalayas.
Inlight of recent events of climatic change, the Himalayan region of Northern India has sustained substantial pressures of economic and infrastructural impendence, with limited access to material resources. This confinement is due to the isolation and altitude in which this region sits, making transportation and material procurement highly tedious and uneconomical. This has changed the existing construction method into a hybrid system that fails to serve both functions of material efficiency and spatial organisation.
SETTLEMENT PATTERNS
Owing to the strategic positioning and geography of the region, the emergence of multitudinous settlements have characterised homogeneous growth patterns that encompass the surrounding elevation in coherence with local knowledge and techniques. The linearity of these settlements is primarily defined by the topography and proximity to water resources. Over the course of many centuries, the survival of the human race is ensured due to the growth in high adaptability to these factors; though numbers are primarily bleak in many of these settlements considering the limited employment options and scope of urbanisation. In the 21st century, these settlements started gaining importance due armed forces and military disputes. The infrastructural growth in the previous decade of 2002-2016 has accelerated, largely to house extensive tourism and migration for spectacular scenic views and extreme sports activity.
In light of the recent infrastructural need to harness resources, various proposals have come up with feasible solutions to redefine the architecture of the region. Although nearly most or all have not been implemented, a brief study to address these prototypes has been done, to understand the scale of priorities in different prototypes.
Amidst this proliferation, the district of Leh is the primary focus to contextualise the work specifically for the accessibility and socio-economic stability of the region that acts as a sole representative to the neighbouring villages of the area. The entire research is driven based on an extensive settlement study of the region in respect to their traditional architectural styles and community living patterns that coherently exist as an autonomous ecosystem.
02-4.1
CONSTRUCTIONAL SHIFT
Change in material system and construction logic to develop vulnerable hybrid building types.
TEMPORAL HABITATION
02-4.1.1
“Contemporary architects have to face a world without certainties to base their work on. They are left in a terrain that is unknown to them and the results of their designs are as unsound as their orientation in a culturally unknown landscape. Long established design guidelines such as locality, place, climate and available building materials have to be reconsidered and placed into a wider context.”
-Professor A. Rieger-Jandl
The internal transformation of architectural metabolism demands an extensive understanding of the domestic dimension and all tangible tectonics pertaining to the performance of the settlement. The intangible aspects constitute the broader framework of knowledge and culture within which the tangible heritage is discreetly embedded. The seasonal shift from nucleated clusters in winter to scattered housing in summer is highly common amongst the local residents. In winters, migration to urban cities as opposed to native resilience is feasible due to lesser frequency of tourists and higher opportunities of short-term employment. The winter dwellings cater to higher thermal conductivity, whereas the summer houses are largely scattered to accommodate agricultural fields. However, materially both typologies require regular maintenance and modification. Mobility in winters becomes highly arduous for any supplies or procurement. Thus food harvesting and storage becomes crucial for survival prior to winters.
Stone and timber sections being the primary building materials allow for total manual assembly which is more favored and durable. The traditional units have limited openings and are usually 1-2 storeys in height.
The use of reinforced cement and concrete blocks with timber sections has led to a new hybrid system to accommodate higher population density. This system requires significant automation and is usually delayed in completion.
The change in material system from vernacular to foreign for rapid modular construction and low maintenance has transformed the region’s architecture significantly. Initially stone, earth and wood were the primary materials, now replaced by reinforced concrete structures. The cost of transportation and constructional logistics are higher in comparison to local materials, and offer limited scope of flexibility for reconfiguration. Thus preserving existing material knowledge is essential to ensure stability and culture of the region. The terrain does not support the foundation requirements of a contemporary RCC structure, thereby making it more susceptible to building failure.
CONSTRUCTION
The construction of a traditional house is highly influenced by the area, not only for its proximity to materials but also the availability of skilled craftsmanship. Almost 65 to 70% of the buildings depend on the experience of local masons as the technique of stone dressing and wood carving is unique to the region. The introduction of foreign materials and their amalgamation with the existing ones have increased the degree of specialization, making construction profoundly demanding and mechanized as opposed to the traditional hand assembly of buildings.
RESIDENTIAL
Internal courtyards and linear balconies are the distinct features to differentiate residential units from other building types. These features permit maximum light and ventilation to the interiors of the dwellings.
RELIGIOUS MIXED-UTILITY
These buildings can be isolated of form a part of a larger temple complex. The external faces and support members are heavily decorated and ornamented to augment the significance and presence of the structure.
This type was initially designed to serve different function and provide flexible interior spaces to be utilized as commercial, educational, residential or a combination of two or more activities.
TYPOLOGY VARIATION
Change in material system and construction logic to develop vulnerable hybrid building types.
The variation in building typologies across various scales is evident based on the environment it is embedded in. Although topography and climatic alterations affect the architecture of the region, the aesthetics and system of construction are extremely reliant on the choice and availability of materials that can endure the harsh environmental pressures.
Since the spatial configuration of each of these buildings is a very complex arrangement, there are certain features that differentiate one building type from the other. The building morphology and the level of detailing associated with religious or more permanent structures like temples and monasteries are far more distinct compared to the residential type. The fenestrations and structural system are primarily timber as the local masons have more control over the material in terms of extracting its benefits. The increasing use of timber rapidly deteriorated the growth of native trees and demanded expensive maintenance. However, on higher altitudes and steeper slopes, stone is the more preferred option owing to its bulk weight and resistance to environmental changes.
The spatial planning gives primary importance to the functional needs more over comfort and durability. Multi-level dwellings with complex interior spaces emerge out of landscape adaptation. Since material availability is sparse and machinic processes are rare, most of the spaces are articulated to multiple levels of functions. Thus, there is no distinct hierarchy of program distribution.
To cope with the rising inflation and for monetary gains, most of these buildings (dwellings + monasteries) have converted into guest houses and residential schools where the spaces have undergone further alterations.
This paradigmatic shift in lifestyle from an isolated agrarian community to a rapidly developing tourist magnet has led to a series of block-type units developed by non-local organisations that increasingly impose pressure on the existing building typologies and their existence.
BHUTAN NEPAL
Linear organisation of settlement oriented on the East-West axis. Mainly row type houses containing linear units with common circulation corridor.
A hybrid organisation of linear and axial settlement pattern with autonomous clusters. Similar architecture is seen with internal variation of spaces.
Axial cluster organisation along primary roads. Close clustering of units observed to contain thermal gains. Mostly all the units are placed along the same contour interval.
Scattered arrangement of dwellings mainly around access roads and farmlands. Units are isolated as farming and self sustainance is the main priority.
TIBET INDIA
02-4.3b 02-4.3d
02-4.3
SETTLEMENT PATTERNS
Existing building arrangements based on altitudes and contour interval across the Hindu Kush Himalayan region.
02-4.3.1
CLUSTER ORGANIZATION THERMAL COMFORT
02-4.3.2
The arrangement of settlements across various countries in the Himalayan region varies significantly based on the infrastructural development of networks and the accessibility to local authorities. Since agriculture, water and networks are the main priority that govern the positioning of these units, they often face inevitable conditions of thermal discomfort, fixed visibility index and internal wind turbulences.
To allow for maximum spatial comfort within the clusters, both in summers and winters, modern interventions should take into consideration the environmental parameters. The orientation of units and their inter-relationship with the adjacent unit largely predicts the effectiveness of the space. By maximising the exposure of south faces, each unit can harness maximum solar radiation and minimise heat loss. As the overall form of the building determines the heat transfer between interiors and exterior, it is crucial to minimise the ratio of area over volume while clustering multiple units together. The closeness between the units creates massive self shading problems thereby reducing the internal heat storage. The formation of wind tunnels between linear unit styles and incremental snow and/or debris accumulation frequently adds to further arrangements of removal and repair.
An analysis of the existing settlement patterns proves the basis of generating possible design drivers for clustering strategies in the latter part of the dissertation.
Current Page(top): Fig| 02.43
Images of Arup Druk White Lotus School, showing Solar panels, main hall. This structure is one of the few surviving structures of leh floods(2010)
(Source: Author)
Next Page(top left): Fig| 02.44
Himalayan water tower: Winning entry for eVolo skyscraper competition 2012: Zhi Zheng, Hongchuan Zhao, Dongbai Song (Source: http://www.evolo.us/competition/ himalaya-water-tower/)
Next Page(top right): Fig| 02.45
Norwegian Mountain Hut: Student initiated project in Bergen, Norway: Design and build workshop by Architect Espen Folgero
Attempts made by various organisations as actual proposals or competition entries to improve the local conditions.
DRUK WHITE LOTUS SCHOOL
02-4.4.1
The rapid change in climate of the Himalayan region has been a global debate for the past few years and has led to various innovative solutions and proposals from international architectural organisations. One of the recently completed projects is a residential school by Arup Associates that effectively harnesses solar energy to sustain the daily energy consumption of the school. Also, the services designed make minimum usage of water resources and convert waste to fertilisers. The project makes smart use of local materials and construction techniques to ensure greater durability. The school is one of the few complexes that managed to survive the 2010 flash floods with minimal damage.
02-4.4.2
Most of the recent proposals have been focused around a common issue of structural or environmental performance. It is noticed that proposed systems have been proved to be effective digitally or physically only at a building scale and not on a settlement scale. A single alienated intervention is bound to have significant problems of utility and maintenance and populating the same would have a terrible impact on the environment and lifestyle of the people. However, an effort has been made to extract the potentials of each proposal and discuss the possibilities of integration in this dissertation.
The next page illustrates the various proposals made at a competition and/or client level and showcase different potentials and limitations unique to each proposal. This study proved beneficial in realising that the proposal should be well integrated with the landscape it is embedded in and should take into cognizance the various implications of the same.
02-4.4a
02-4.4c
HIMALAYAN WATER TOWER NORWEGIAN MOUNTAIN HUT
Potential: Perennial water availability Limitation: Technological Maintenance
The proposal revolves around maximising water resources by freezing water from precipitation and storing it for future use.
This was proposed as high tech energy efficient unit functional on wind and solar energy. However complete reliance on environmental factors can never be entirely successful.
The proposal was developed on the logic of a deflatable system that could be carried from place to place.
NEPAL MOUNTAIN HUT
02-5
CONCLUSIONS
Formulating research goals and extracting relevant techniques, while critically analysing state of the art solutions.
LANDSCAPE CONTROL
02-5.1
Exploration done during chapter two indicates towards a large-scale intervention as opposed to building or cluster level developments where debris mitigation and resource economy are seen as primary domains. All techniques explored in the chapter are seen as isolated attempts to solve short-term problems that lack any integration with the existing landscape or dynamic adaptation to time or seasons. A successful design intervention in the cold desert biome would mean exploiting the embedded intelligence from the current landscape and adapting towards a sustainable model for growth in the future.
HAZARD PLANNING
02-5.2
RESOURCE MANAGEMENT
02-5.3
The incremental tourist influx has led to disruption in the supply and demand chain of the region. The old settlements patterns that were capable of retaining earth have now been replaced by concrete frameworks to cope with this growing pressure. Thus a deeper understanding of the terrain is required to develop a sustainable growth model that can keep up with the demand of the area, not just in terms of infrastructural support but also the growing need for food and other social utilities.
Water, food and fuel being an important resource for sustaining life, becomes of prime importance in these cold desert type regions. Water harvesting strategies such as artificial glaciers are seen as one of the potentials on site. Agricultural practices being archaic requires strategic intervention, as food production is only possible during the summer months. Certain bio-engineering slope stabilisation strategies coupled with groves densification can provide stable lands for construction while annually supplying fuel (firewood) to the inhabitants.
BUILDING SCALE
02-5.4
At a unit level, the architectural development in the Himalayan region has been stagnant for more than three decades. The lack of social attention from local authorities has subsequently delayed the technological advancements made in construction today. The existing built fabric can no more sustain the pressure of population migration and climate change; thereby increasing the need for conscious dual purpose planning of short-term building development and long-term environmental impacts.
RESEARCH AMBITION
02-5.5
The domain provides for sufficient indications to formulate the goal of this research. A system that can incorporate the potentials of the terrain it is embedded in, to reduce external pressures of material procurement and successfully stabilise resource statistics through emergent technologies would be the premise for shaping this dissertation.
TOWARDS
A RESOURCE DRIVEN SETTLEMENT
Inferences drawn from the study, arguing a case for resource driven settlement strategy
LOGISTIC CONTROL
HARVESTING RESOURCES
The logistical challenges that arises from importing goods manifests in relatively higher cost living. The cost of construction material is 3 times higher as seen other parts of India, indicating towards a local resource driven sustainable growth model, that delivers on the settlements economic and social needs and a systematic approach that can deliver a cost effective solution to the needs of the people in these cold-dry climatic regions.
Water being the important resource for sustaining life, becomes of prime importance in these cold desert type regions. Water harvesting strategies are seen as potential on site. Since most of the precipitation happens in terms of snowfall , topographical runoff model may present qualitative analysis for strategies to be applied. Harvesting water locally may provide self proficiency within clusters or settlements and can improve food production in the region. The placement of greenhouses to produce food throughout can be a valuable addition in the cold environment, the maximum viable population can be estimated in accordance to the typical consumption patterns and agriculture output of the designed model. Earth being the most abundant material is seen as a possible solution towards a sustainable development in the remote highlands. Soil loss due to topographic and climatic factors often gets collected in the rills and inter-rills of mountainous regions as scree and rill deposits on the foothills. These sites can act as potential collectors to serve as a material production sites. A topographical model can be generated to understand the region. This model can be fed as an input to various mass movements programs to generate annual soil loss and cloudbursts erosion models. An integrated risk analysis can be conducted with this created digital environment that can have integrated approach with clustering and landscape strategies. This growth model can be evaluated on its shear capacity to mitigate and to retain soil loss for both safeguarding from the cloudbursts event and yet utilising the same for suture developments.
FUTURE GROWTH
The extraction or harvesting large amounts of soil and debris for construction is a process that might have undeniable impact on the landscape, both visually and environmentally. The segregation of inhabited areas and deposit fields required for debris segregation and collection may prove to be a sustainable model of growth. The occupation of elevated areas integrated with well designed network systems that can control erosion in the settlements areas and prevent the mass flow build up a the peaks may be a solution to control the velocity of water, making a redirection/mitigation measure possible due to reduced velocities. The biggest advantage of doing so, would not only safeguard the inhabited areas (even agricultural field) but also utilize these natural events to a positive advantage, leading towards a sustainable growth model for other settlements, set-out under similar conditions.
An opportunity to combine landscape and clustering strategies, to sustain population and mitigate the mass flows, might arise through a sequential occupation strategy, where settlement growth is guided by the placement of various clusters to redirect or restrict the flood flows. based upon their evaluation a risk analysis can be conducted to find the best suited differential growth patterns. These clusters can be dynamically integrated with various environmental factors (such as debris flow , water accumulation, total radiation and self shading) to give rise to a differential growth model that has full autonomy over its sustenance and growth.
RESEARCH AMBITION
The above inferences clearly indicateds towards an in depth analysis of the physical attributes of the site. An qualitative and quantitative investigations on soil erosion dynamics coupled with cloudburst flood scenarios is required to delineate any design strategy for the region. Above all a clear understanding of various earth construction techniques are required to develop livable units or clusters, that can uphold their structural integrity when loaded with these mass flows from various directions.
Geo-Spatial
Synthesis Tools
Design Methods
Analytical Tools
MASS ACCUMULATION
Developing strategies to effectively control mass movement and reduce the effect on lower planar regions.
RAMMS SIMULATION
ANNUAL PHASING
Debris flow simulations run for a period of 0-10 years to test the effect of developed strategies.
DESIGN PATCH
Extract smaller patch from data acquired from site synthesis for design development and settlement strategies.
HYDROLOGICAL CONTROL
Maximise water harvesting through accumulation strategies coupled with seasonal changes.
RESOURCE MANAGEMENT
Increase rate of agricultural produce per capita to control import of materials and packaged food into the region.
AGENT BASED SIMULATION
Agent based modeling based on rule sets of least resistance and maximum intersections of hydrological flow lines.
GENERATIVE ALGORITHM
Optimising land use pattern using environmental parameters and soil loss coefficients for target population.
BUILDING MATERIAL
Volume of material salvaged post mitigation to generate clusters based on proximity and risk map zoning.
WATER RESOURCES
Volume of water available for regular consumption considering effects of seasonal change and secondary activity.
SETTLEMENT GROWTH
Initial cluster positions and patterns as a resultant output to optimise further in design development.
OVERVIEW
Integration of multiple techniques during both research and design stages
The complexity of various ecological systems demanded an extensive integrated set of techniques, where transfer and re-interpretation of data were possible at different scales of the project. Initial data mining and extraction were accomplished through Online research and on-site investigations, where image sampling helps with data mining, and image processing provides data interpolation capabilities. Multiple analysis within different mediums required, development of specific iterative loops and data transfer algorithms to integrate results within a single medium (i.e. Grasshopper for Rhino)- A visual programming language, developed by David Rutten for Robert McNeel and Associates, as a plugin for Rhinoceros 3d CAD application.
Production of various debris flow simulations at different scales helps device strategies within the digital medium, where the impacts of these designed strategies get integrated within the flow simulations inside an iterative loop, where we constantly modify these strategies in order optimise towards a desired target. These strategies serve a dual purpose- to increase resource production(food and timber) and reduce soil loss; stochastic calculations using tree and crop yield rates were embedded within the model for wood and food production, while RUSLE (Revised Universal Soil Loss Equation) gets embedded for soil loss estimation. This research culminates as a land use pattern; acting as a foundation for further design development. At cluster-level, social and environmental parameters extracted during initial phased get integrated within the design model, where the clusters get optimised for new criterions. A custom designed circle packing algorithm further optimises building positions under environmental and spatial characteristics.
Structural performance of earthbags is also explored using scan and solve (plugin for Rhinoceros 3d application), where earthbags limits of different sizes were tested against flow pressures and velocity, later used as a feedback loop to determine unit dimension restriction based upon the unit placement within the hazard zone.
The final units were evaluated for various ecological parameters to ensure an environmentally effective and strategically accessible building relationships. ANALYSIS OBJECTIVE
Current Page (left) : Fig| 03.02
Picture of author while working in the Zanskar valley, showing en-route village to pangong lake in the background, the village is one of the most remote villages in the region.
(Source: Author)
Current Page (right) : Fig| 03.03
Picture of author while working in the old town of Leh. Handling the list of owners of the house, preparing for the next set of interview.
(Source: Author)
Next Page (right) : Fig| 03.04
Picture depicting various layers within a Hazard predictive model.
On site interviews and measurements were recorded to create base data.
Data extraction from various sources stands as the primal backbone of this research. Various journals from some scientific organisations are consulted, to draw parallels from their works, such as IPCC (Intergovernmental Panel on Climate change), ICIMOD (International Centre for Integrated Mountain Development), LAMO (Ladakh Arts and Media Organisation). Data extraction from the stated sources helped to develop a rigorous understanding of the fragile Himalayan ecology. Moreover, prepared us for further investigation into the region. Although the most important methodology in data collection has been the visceral site information collected from local sources; this played a vital role in deciding design strategy, within the environment.
A month long on-site investigations led to a series of insights into the environmental and sociological complications (Refer chapter 2 and appendix for details) Besides physical mapping of various ruins and old city blocks, physical soil sampling is done to understand, its textures and composition. Also, rigorous interview sessions with the inhabitants of the area are conducted, which concluded with an overall study of the social infrastructure and agriculture facilities in the valley. Further exploration into adjacent valleys highlights similar problems of mass movements and food production deficit along with the common lack of infrastructure.
03-3
GEO-SPATIAL PREDICTIVE MODELLING
Understanding various hydrological factors influencing landslides and soil in cold desert climate
HAZARD MODELLING
Occurrences of events are neither uniform nor random in distribution– there are spatial environmental factors (infrastructure, sociocultural, topographic) that constrain and influence, where the locations of events occur(Garry. P et al., 2006). The technique delineates these constraints and influences through correlation of occurrences from past events with environmental factors representing those events. Geospatial predictive modelling has two types:
Deductive: Relying on qualitative data or subject matter expert (SME) to determine relationships between event occurrences and factors describing it.
Inductive: It relies on empirically calculated spatial relationship between past events and its factors. As the deductive technique relies only on personal information; limiting the model by inputing some factors that human brains comprehends. Whereas, the latter technique– harnesses the processing power of the computer; running smart algorithms, it can provide relationships between both known and unknown factors, between more than one event. Statistical functions are made to analyse these relationships, determining spatial patterns defining event occurrence probability in the given area.
The project relies on inductive modelling technique– where data collected from past event/s gets analysed, where relationships between its factors get calculated for each land unit. This data helps plot a probability function for the complete study area. Although the test patch being highly remote had insufficient data thus improvisation was required, that led to the implementation of a Deterministic Approach– where a library of factors affecting the event (debris flow, slide) are determined, and a probabilistic approach was applied as suggested by (Hammond et al. 1992). To overcome the limitation of probabilistic functions i.e. lack of statistical data, special attention is given to different soil types and terrain related factors. Various digital techniques such as, image sampling and interpolation techniques are used as an attempt to factor in as many possible variables for producing factor maps and relationships are extrapolated through regressive equations.
PHYSICAL ATTRIBUTE SAMPLING
Technique devised to interpolate and quantify missing data via images and pixel mapping. 03-4 03-4.1
IMAGE PROCESSING
Current Page (left top) : Fig| 03.05
Top view of leh valley
(Source: Google earth)
Current Page (middle top) Fig| 03.06 Hill shape map of Leh, with embedded data physical data
(Source: Author, generated from Arcgis)
Current Page (right top) : Fig| 03.07
D.E.M model of Leh valley.
(Source: Author, generated from grasshopper)
Next Page (top): Fig| 03.08 diaram showing a 3dimesnional graph with red line indicating obtained fucntion as close as possible.
Next Page (bottom): Fig| 03.09 Flow diagram showing workflow within predicitve hazard modelling
(Source:Author)
D.E.M Soil Maps Slope Data Forest Data Building data Hydrology Data
Image processing as the name suggests quite literally is delineating the information inside a picture through various data processing techniques such as, algorithms or processing. This technique is used during the project on multiple occasions, primarily inside ArcMap 10.4.1® and Grasshopper for Rhino®. LIDAR– primarily a surveying method that measures the distance between targets using laser light, producing hi-resolution maps of the geomorphology.
The range of variable was extracted during the post processing of LIDAR images inside the various third party software. Pre-built algorithms were used to convert the picture into D.E.M (digital elevation model), and different facets such as mountain gulle y’s, forest areas and soil data were extracted. Whereas, algorithms were written inside Grasshopper for Rhino to extract flow accumulation, slope drainage, slope rise, etc.
Multivariate extraction from a single source is one of the primary advantages of this technique. The information extraction is made possible through pixel mapping. Bi-cubic interpolation was implemented to generate data for pixels that was missing any /all data.
03-4.2
PHASING FUNCTIONS
A modified version of regression where relations between unknown factors are determined
A statistical methodology is used to delineate or predict the relationship between multiple variables. There are various techniques for modelling and analysing multiple variables. Regressive interpolations is used during the project to determine the relationship between multiple variables such as elevation, slope, soil parameters, hydrology, etc. to predict landslide and erosion rates as many unknown parameters were involved which were beyond the scope of the project.
The the best fitting evaluation between multiple parameters is determined, after multiple iterations of the model, which tested the deviation from the base graph (i.e., the previous landslide/ erosion event). The equation is later incorporated into the digital model as an abstraction of different induced relations to predict susceptibility events for the test patch. Wolfram Mathematica plugin (Stephen Wolfram) is used to find the polynomial function inside Grasshopper for Rhino.
03-4.3
WEIGHTED DISTRIBUTION MAPPING
To generate relationships between complex events based on differential weighting logic.
Complex events which are a consequence of its various subsets, amalgamating together in differential amounts, are often difficult to understand. Weighted mapping distribution is a technique based upon mathematical partitions(number theory) that help to generate an in-depth understanding of these events. The above methodology predicts the probability of such an event by assigning weights to the various subsets, that is, remapped under a cumulative domain, which gets equated with a fitness value that corresponds to the worst-case scenarios.
Using the above methodology many hazard susceptibility maps such as landslides, flash floods and earthquake can be generated by delineating the event into various subsets (even adding more subsets, for a more comprehensive understanding). The analysis data set is broken down into smaller units (cells), and empirical data mapping is carried out for all parameters on every cell. This data with variable ranges get remapped under a common domain. The resultant is a cumulative value for each cell which later gets remapped within a domain of (0 to 1).The output usually is an index which corresponds to a scale from 0 (low) to 1(high), which gets mapped to the data set in a colour code gradient. The colour gradient is the resultant corresponding cumulative value for the desired result.
LIDAR MAP
03-5.1
CARTOGRAPHIC MODELING
Cellular mapping technique to generate different factor maps from various ecological parameters.
03-5.2 MASS MOVEMENT SIMULATION
Physical mapping is a procedure used to calculate various parameters of a test surface/terrain. A cell based mapping approach was taken inside a visual programming ( Grasshopper for Rhino) software, along with scripting components (C#). The results then were weighted and remapped under a probabilistic function.
Grasshopper being a single core application, fails considerably in performance, when formatting large amounts of data. This limitation was overcome through scripting (C#) various procedures within the visual programming software. Also, the test patch being a surface has to be subdivided into cells before commencing mapping procedures., which directly affects the accuracy of the result– the more the density of cells the higher accuracy, or vice-versa. Although, the calculations were simplistic in nature, but were highly time consuming due to which the calculations were done in batches; grouping cells for convenience.
The most important advantage of using the cell based physical mapping was the excessive redundancy and control over the test patch. One can control the size, density and orientation of the cells, as per the designer/analyzer’s instructions. Once the data is produced the grasshopper allows the use various analytical tools within its interface, this data can be either mapped onto the surface of directly exported into another application and analyzed further for a more comprehensive analysis of the test patch.
A recently developed lithological tool that analyses different mass movement scenarios.
RAMMS (RApid Mass MovementS) is a state-of-the-art numerical simulation model to calculate the motion of geophysical mass movements (snow avalanches, debris flows, rockfalls) from initiation to runout in three-dimensional terrain. It was designed to be used in practice by hazard engineers who need solutions to real, everyday problems. It is coupled with a user-friendly visualization tool that allows users to easily access, display and analyze simulation results. New constitutive models have been developed and implemented in RAMMS, thanks to calibration and verification at full scale tests at sites such as Illgraben (debris flow), Veltheim (debris flow, mitigation measures), Vallée de la Sionne (snow avalanches) and St. Léonard (rockfall, mitigation measures).
These models allow the application of RAMMS to solve both large, extreme avalanche events as well as smaller mass movements such as hillslope debris flows and shallow landslides. RAMMS was developed by the “Avalanche, Debris Flow and Rockfall” research unit of the WSL Institute for Snow and Avalanche Research, SLF. The interface describes the features of the RAMMS program in great depth - allowing beginners to get started quickly as well as serving as a reference to expert users.
Previous Page (top) : Fig| 03.10
Factor maps created from previously generated data sets and statistics.
Soil loss map generated from Universal Soil Loss Equation
(Source: Author, generated from grasshopper)
03-5.3 SOIL LOSS ESTIMATION
To calculate annual loss of soil due to surface erosion; a prime catalyst for accelerating mass movements
A parameter based erosion model called USLE (Universal soil loss equation) - developed by Wischmeier and Smith(1961) was seen as a possible method to calculate soil erosion quantities. Although the method is a lumped empirical model that does not separate factors that influence soil erosion ,such as plant growth, decomposition, infiltration, surface runoff and soil transportation.
The USLE was designed to estimate sheer and rill erosion from hillsope areas (Renard, et al., 1997) . Thus the equation was modified in 1997 and is known called RUSLE(revised soil loss equation. Thus we chose to use the revised version, the five main indicators are as follows:
K: Predicted average soil loss R ( Req): Rainfall erosivity factor
LS: Slope length factor
P: Conservation practices
C: Cover and management factor
The parameters R , K, L and S factors primarily influence erosion volumes, whereas P and C factors influence rate of erosion. The K and LS factors are varying with landuse change (especially if one is building in certain areas, because a change in the terrain is introduced disturbing previous values. C and P factors are directly linked with Land-use with each practice assigned a specific value between 0 -1.
Soil Loss Gradient
DESIGN METHODS 03-6
03-6.1
CIRCLE PACKING
To devise clustering strategies against residual mass flows
Current Page (right) : Fig| 03.13
Sample diagram to represent alignment of different circles with no overlaps.
Circle packing is a commonly implemented technique based on a mathematical theorem where planar circles within a fixed diametric domain result in a tangential alignment without any overlaps. Each circle can be assigned particular values of plot size or building density to generate maximum number of circles that can be “packed” in a closed geometry.
Packing algorithms can be executed in many ways, however the focus is around weighted delaunay triangulation where circle packing representation of a graph realises the graph as the weighted delaunay triangulation where the vertices are the centers of the discs and the assigned weights are the radii. (Pratt et al. 1998)
In this research, this method is used to find maximum interconnections between consecutive units with respect to their orientation and function. The permutations and combinations of different packing schemes result in discreet analogs of conformal mapping.
A structural simulation plugin inside Rhino that does not specifically require meshes as inputs.
Scan & Solve TM for Rhinoceros can completely automate basic structural simulations of solid objects. This tool requires scientific data of material properties and directionality of impact forces with their respective pressure values. As opposed to conventional structural analytical tools, this plug-in requires no pre-processing (meshing, simplification, healing, translating, etc).
This plug-in is used to run structural analysis of different earth bag dimensions to record the maximum displacement values under differential pressures of debris forces. The tool provides for comparable results to evaluate a plausible system that can be implemented as an autonomous unit to resist maximum and minimum mass flows.
This diagram is a representation of a genetic algorithm process developed and presented at the IASS IACM-2008, for acoustic optimisation of a reinforced concrete shell.
Genetic algorithms developed to discuss variable outputs as constants/inputs in later stages.
DEFINITION
03-6.3.1
A genetic algorithm (GA) is a method for solving both constrained and unconstrained optimization problems based on a natural selection process that mimics biological evolution. The algorithm repeatedly modifies a population of individual solutions. (Genetic Algorithm - MATLAB & Simulink)
BENEFIT
03-6.3.2
Multi -objective optimisation is a process that tests the possibilities of combining more than one input parameters against contradicting criteria of fitness. In this research, the technique is used at several stages of work especially where large scale landcape interventions were involved. A sensitive terrain cannot adhere to one specific result thus it became necessary to allow the system to be open to a range of possible variations. However, for the sake of progress and evaluation, the fittest individual was carried forward into the next level of analysis. The primary benefit of utilising this technique is the computational capability of generating rapid individuals based on stochastic calculations. Special care was taken in developing the genetic algorithms since large data sets were involved that could lead to pseudo-pareto optimals.
PRECAUTION
03-6.3.3
The combination of two or more genetic algorithms was strictly avoided to ensure clarity in segregating various strategies. Since most of the input parameters were generated from third party softwares, the integration of multiple variables could lead to excessive computational load and redundancy.
Current Page (right) : Fig| 03.15
ANALYTICAL TOOLS 03-7
03-7.1
SOLAR RADIATION
Optimising the environmental performance of units based on indigneous cluster analysis
Solar radiation is of prime importance in a cold desert biome like Leh Ladakh, thus signifying the importance of using this tool for environmental analysis and optimisation. Solar access and radiation values from initial cluster analysis was set as the base data with an attempt to maximise surface radiation in the design proposal. Radiation also affects the rate of agricultural production in the region and this was taken into consideration to maximise crop radiation efficiency to maximise the annual output.
03-7.2 MUTUAL SHADING
Deriving clustering logics to attain minimum self shading between connected units.
The existing settlement study proved that mutual shading between clusters minimises solar access to the neighbouring units and internal courtyards thereby causing low internal temperatures. However, spacing the units leads to increased heat dissipation which would be unsuitable in the Himalayan context. Thus the shadow and radiation analysis done inside the Ladybug plugin for Grasshopper suggested numerical values that could be interpolated as design drivers to minimise self shading.
Current Page (right) : Fig| 03.17 Shade and Shadow analysis of the above clusters to illustrate mutual shading on internal courts.
(Source: Author)
Current Page (right) : Fig| 03.16 Radiation analysis of different cluster types from Ladybug_gh.
(Source: Author)
Current Page (right) : Fig| 03.18
Example of agent based modeling on a topographic surface using logic of generating paths of least resistance.
To simulate the directionality of residual flow lines based on differential topographic gradients
Agent-based modeling (ABM) is a developing approach adapted by scientists and researchers in geo-spatial studies to comprehend complex dynamic flow systems. The logic of this method is based on the connections established between initial release points and final destination points. The trajectories produced by the agents depend on the topographical variation and can be used to extract qualitative data for further experiments.
This method is used at multiple stages of the research in devising linear interpolation of hydrological flows and checking for deflection mechanisms to increase efficiency. Based on varying slope gradients, the paths of least resistance provide meaningful information to evaluate the designed interventions.
03-7.4
CENTRALITY
Analysis of rural network systems based on walkability index on steep terrains.
Powerful, but not central Central but not powerful
Current Page (above) Fig| 03.19
Simple diagram explaining concept of centrality in network patterns.
(Source: Redrawn from - http://www.lboro.ac.uk/gawc/rb/images/ rb365f1.jpg)
Closeness centrality is defined by the total length of the average shortest path between the central vertex and all peripheral vertices in a network system. Since the development of clusters is emergent based on the rate of resource production, the possible integration of a cohesive network has been simulated and analysed using the Spider Web plugin inside Grasshopper.
As opposed to urban street networks, walkability is the predominant factor that governs the success of a rural mountainous setup. Thus the logic of a settlement growth pattern and localised cluster expansion has been established based on walkability radii within a fixed domain of slope gradients.
SITE SYNTHESIS
Overview
Study Patch
System Logic- Mathematical models
R.U.S.L.E Analysis
Qualitative Weighted Analysis
R.A.M.M.S Simulation
INDEPENDENT MATHEMATICAL MODELS
DEPENDENT MATHEMATICAL MODELS
TERRAIN DATA
Consisting of slope gradients etc.
SOIL DATA
Contains soil attributes such as permeability etc.
STUDY PATCH
CLIMATE DATA
Shows wind and temperature attributes.
Based upon factor maps Based upon RUSLE + Weighted Maps Based upon differential weighting
HYDROLOGICAL DATA
Depicts wetness and various other indexes.
INTEGRATED RISK MAP
Based upon risk maps integration of all maps
ANALYSIS
OVERVIEW
Deterministic debris flow modeling performed through specific attribute analysis of various contributing attributes.
Duley and Hays suggest that erosion and sedimentation is a function of various primary and secondary attributes of terrain (Duley and Hays, 1932) – An investigation is made to analyse these attributes qualitatively. The objective is to identify areas of maximum and minimum soil loss, equipping us with relative information to implement various strategies. The generated qualitative models accommodate different factors (such as slope gradients and soil texture), which provides a base to develop growth strategies. This chapter deals with determining and analysing these attributes and in turn "prepare" the site for any design intervention.
The approach described by (Wischmeier and Smith 1978) is utilised here that integrates soil loss of terrain with its physical attributes– Also known RUSLE(Revised soil loss equation). Considering the complex nature of the terrain and computational tools( Rhino and Grasshopper). A modified approachCellular grid based scenario is considered (because the tools used, utilises meshes and surfaces to compute geometries). Thus, the modified cell-based approach described by (Mitasova et. al. 1996) is adopted. The patch is divided into 20m x 20m cells (to limit the computational load), where, each cell gets analysed for a selected attributes such as slope angle, slope aspect.
The attribute analysis is conducted in many ways- Figurative, Qualitative and Quantitative data sets. Here the desired attributes then go through a qualitative weighted analysis using Binary index overlay method ( due to an overwhelming number of attributes). The data tables created are then utilised to generate a deterministic analysis of the selected patch. This analysis provides an overview of the nature of the terrain where each cell is rated based upon the risk of erosion, rainfall collection(wetness index) and cumulative deposition from neighbouring cells, culminating into various synthesis maps, with a ranking of each cell. These qualitative datasets are utilised to generate factors of safety with regards to both deposition and erosion on site.
Old City
SABO VILLAGE
LEH VILLAGE
Test Site
STUDY PATCH 04-2 SITE EXTRACTION
04-2.1
Extracting a Study patch based upon growth patterns studied on-site.
The selection of the study patch is an outcome of the site study (explained in the later stages) where the growth patterns of the city clearly depict future extensions( refer Fig. 4.2). The test patch chosen is a continuation to the eastern fronts of the Leh valley, since, the city has almost engulfed most of the valley floor and now looks towards the surrounding hills for extensions. Previous flood events and settlement growth direction, influence test patch selection from the study site. The patch has an area of 9 km2, and the height variation is 3487- 4211 metres (a.s.l).
STUDY PATCH
Area: 9.0 sq.km
Cell Size: 20*20 m No. of cells: 19762
STUDY SITE
Area: 246.59 sq.km
Cell size: 200 x200 m
Previous Page (complete page) : Fig| 04.2
Satellite image of Leh and surrounding settlement village, showing settlement growth direction
(Source: Drawn over Arcgis, By Author)
Current Page (right) : Fig| 04.3
Digital elevation model of Leh Terrain showing the Test patch with its dimensions.
(Source: Author)
SYSTEM LOGIC 04-3
Sequence depicting logic-progression for deterministic analysis for multiple independent and dependent attributes.
STAGE -01
Complete Spread : Fig| 04.04
Diagram depicting the logical flow of factors and attributes to attain final risk mapping within the desired study patch.
(Source: Author)
Note: All maps shown in the diagram are for graphic purpose only, they are elaborated subsequently on their assigned pages.
CLIMATE
Annual Wind Forces Annual Radiation
Seasonal Hydro-graphs (Worst case scenario)
GEOLOGY
TEST SURFACE
Texture Permeability
Aspect
Curvature
Degree
Elevation
Rise
Length
Tree Cover
Crop cover
Structures
Factor
Factor
Factor
Factor
INVENTORY MAP
LITHOLOGY HYDROLOGY
Accumulation Direction
Factor
FACTOR MAPS
RELEASE AREAS
FLOOD MAP
EROSION MAP
WEIGHTED CROSS TABLE
EVALUATION LOOP
SUSCEPTIBILITY
RISK MAP
BINARY INDEX OVERLAY
DEBRIS FLOW ANALYSIS
04-3.1
MATHEMATICAL MODEL- TERRAIN
Understanding various terrain based factors translated into synthesis maps.
Slope Elevation(m) (10-90)
Current Page (left top) : Fig| 04.5
Mathematical model showing the various elevation range on study patch.
Current Page (left Bottom): Fig| 0.4.6 Mathematical model showing various slope degree range across the study patch.
Current Page (right top): Fig| 04.7
Mathematical model showing curvature across the entire study patch.
Current page (right bottom): Fig|04.8
Mathematical model showing slope aspect across the study patch
Next Page (left top): Fig|04.9 Logic diagram depicting slope angle and percentage calculation using vector based math.
Next Page (left mid): Fig|04.10 Logic diagram depicting slope curvature calculation using vector based math.
Next Page(left bottom): Fig|04.11 Logic diagram depicting slope curvature calculation using vector based math. (Source for all: Author)
Slope Curvature (Convex to concave)
Slope Gradient(%) (0-60)
Slope Aspect (N-S)
ELEVATION
Previous studies reveal that the inhabitants usually occupy land from the foothills of the mountains till 50 -75 meters on the hills, above these heights, monasteries or holy tombs are the only buildings present, this is because that most of the irrigation only happens in the flat lands of the valleys. The fact that most of the debris and soil erosion activities are initiated at higher altitudes; it became necessary to understand the elevational variations and the threshold heights of these slides on the study patch. The target patch consists of two distinct valleys with the highest point situated on the north-eastern side. The Figure (Fig| 04.5), clearly depicts the range of elevation within site (3540- 4995 m a.s.l), whereas , depicts the buildability domain of the present settlement structure.
u= Slope direction vector
g= ground parallel vector
h= vertical vector prep from ground
z= Normal vector to u
Ø= Slope Angle
Slope Angle
Ø = cos -1 [(|u.g ) / (|u| g|)]
u= Slope direction vector
g= ground north vector
u n = Projected slope vector
Ø= Slope Angle
Slope Aspect
Ø= cos -1 [( un.g|) / ( un| g|)]
The degree of slope on a terrain has long been considered one of the major factors governing the amount of run-off and soil erosion. With a 1-degree change in the slope, the erosion rate increases manifolds (Duley and Hays, 1932). Besides erosion slopes also dictate buildability on rough areas. From the previous studies; slopes >30 degrees act as most likely sites for construction by the people of Leh. Moreover, any slope < 15 degrees required a cut-fill strategy for a stabilised base. The slopes also play a major role in determining the heights of the building at various elevations. Leh being a cold desert type environment requires thermal gains from the sun to optimise temperatures inside buildings. Thus it became necessary to understand the dynamics of slope degree on the study patch. The test patch indicates that the majority of the terrain contain slopes between 25- 35 degrees o, with flat areas lying on the valley floor and the rill areas (Refer Fig| 4.7). Considering slopes at lower elevations, only 4 km2 of are is buildable (out of 9 km2) of site area.
The compass direction of a slope face is called slope aspect (Nwcg.gov, 2017). The aspect affects the topographic features of the slope (Barbour et al.,1999). In the northern hemisphere, the north slopes are shaded for the maximum time and receive the highest sunlight in the southern hemisphere. Thus, in the northern hemisphere, a south-facing slope are therefore generally warmer than a north-facing slope, affecting both the soil structure and biotic life. In the Himalayas, north facing slopes are cold, dry and heavily glaciated as compared to the south-facing slope which is wet, warm and-and forested. Similarly, the subsoil structure is more developed on the southern slopes and have higher organic content as compared to north facing slopes, which are more susceptible to soil loss and slides.
Besides direction and angles, the curvature of slopes also affects the movement of soil upon its surface. Slope curvatures are determined mathematically, where the angle between each mid point of the cell and vertical plane of the flow line is calculated individually. The curvature is either positive or convex (indicating peaks), negative or concave (indicating valleys), or zero (indicating flat surface). While convex (negative) profile curvature locations, the erosion will prevail while depositions occur in places with concave (positive) curvature (Wood, 1996). Slope curvature also plays a major role in directing flows towards valleys and also controls the velocity of movement. Thus it becomes extremely vital to be accounted for during mass movements.
04-3.2
MATHEMATICAL MODEL- SOIL
Understanding various soil based attributes and generate mathematical models for the same
K= Soil erodibility factor (ton h/mj/mm)
S.O.M= Soil organic matter content
M= Product of primary particle size fractions
S= Soil structure Code
P= Permeability class Soil Erodibility
Page
04.12
Previous Page (left mid): Fig| 0.4.13 Mathematical model showing % of silt content on the test patch.
Previous Page (right top): Fig| 04.14 Mathematical model showing the % of sand content on test patch.
Previous Page (right mid): Fig|04.15 Mathematical model showing % of organic matter on the test patch.
Previous Page (bottom right): Fig| 04.16 Mathematical model showing gradient factor of soil erodibility on the study patch.
(Source for all: Author)
SOIL ATTRIBUTES
04-3.2.1
When constructing any building over or underground, one should be well versed with the condition of the land. The study patch being a part of the highest plateau in the world has widespread earth consisting of rocks, pebbles, silt, loam and various other varieties of soil depending upon the locations. The majority of the soils in the middle to the upper Himalayas are sandy to sandy loam in texture and medium to medium-high (e”0.75%) in organic matter with poor water holding capacity (DIHAR,2005). The correlation analysis reveals that clay (%) and silt (%) are (p<0.05, p<0.01) negatively correlated with the altitude, whereas sand (%) is positively correlated with the altitude. Correlation analysis of properties among each other indicates the negative correlation between S.O.M and silt+clay (%). However, sand (%) content is positively correlated with SOM (DIHAR,2005). These attribute analysis not only help determine feasible sites for construction but also, provide in-depth information that helps in predicting soil behaviour under various scenarios.
SOIL EROSION
04-3.2.2
Erosion susceptibility of different soil types varies with its chemical and physical composition. The probability of land resistance to detachment and transport is a function of its soil grain size, permeability, organic content, clay content and sand content. Due to the harsh terrain and dry sandy soil, detailed survey’s were not possible. Therefore, a generalised soil texture map is constructed from various samples collected from the site and other scientific reports. Sandy loam soil texture is observed in the entire area with varying internal sand, clay, silt and SOM (organic matter) compositions.
SOIL ERODIBILITY
04-3.2.3
A function that describes the resistance of soils to movement and transport, also known as soil erodibility factor (K factor). The factor (K) depends upon the organic matter, texture of the ground and its permeability. It nominally varies from 70/100 for the most fragile soil to 1/100 for the most stable soil (Fao.org, 2016). These factors are greatly affected due to the underlying geology and vegetation cover. For the Study patch, each soil attribute is estimated based on various scientific researches and some samples collected during the site visit, in accordance to which mathematical models are delineated. Soil factor(K) is established using the approach described by Wischmeier and Smith,1978 (Refer Fig| 04.16), where the equation describes soil erodibility factor as a function of its attributes, such as silt, clay, sand and SOM. Assumptions, such as soil become less erodible with a decrease in silt content, regardless of any increase in clay or sand (Wischmeier and Smith, 1978) sets as crosscheck parameters for the determined values of erodibility factor. A grid of 20m x 20m cells is used to divide the study path, where the data of each attribute is extracted from the corresponding cell and utilised to determine its K-factor. Certain constant values of S and P are calculated prior that ranges from (2-3) and (2-4) respectively, depending on the elevation of the cell. The K value calculated for the region varies between 0.231 and 0.352.
Previous
(left top) : Fig|
Mathematical model showing the % of clay content on test patch.
04-3.3
MATHEMATICAL MODEL- CLIMATE
Delineating various climatic parameters affecting landslide in the region
Next page (top right): Fig|04.20 Mathematical model showing probability of wetness on the study patch
Next Page (left mid): Fig|04.21
direction map for the study patch.
(Source for all: Author)
Wind directly affects erosion of soils; it is considered that the wind speed has to exceed 6 m/s over dry soils (www.fao.org,2017) for extreme erosion. While movement of small, distributed particles begin with light gusts of wind, however, wind speeds of 0.8 – 1 m/s create significant amounts of erosion. The erosion process is directly proportional to the frequency and velocity of the winds. Also, sandy loam, rich in silt and other minerals is more prone to erosion (Bagnold,1937). Cold, dry deserts of Ladakh receive scanty rainfall; leading to barren land features. These features are more susceptible to more wind erosion than the slopes on the plains. Often flattening crop fields in drifting debris; robbing the rich top soil. Thus the wind is considered as a major contributor towards soil loss and further documented. Wind data is extracted for the test patch using weather files created through metronome climate consultant, providing annual wind speeds/day/hr. Which gets embedded, within a mathematical model as a cumulative average of the velocities, exposed per face on the study patch.
Radiation on a surface has a significant impact on the local micro-climate of slopes. High radiation receiving slopes are more prone to frequent freeze and thaw resulting in soil decomposition and rock breakage; dismantling the top soil layer into further granular particles, which gets transported by the wind or shallow runoff. Thus annual radiation values extracted from various weather files gets embedded inside a cell based mathematical model. This model can later be used to estimate the contribution of the corresponding attribute towards future soil loss on the site.
04-3.4
MATHEMATICAL MODEL- FLOW
Understanding various hydrological factors influencing landslides and soil in cold desert climate
Hydrological flows have always been shaping the Himalayan Lands, with varying topographical features it becomes essential to account for theses parameters and delineate their contribution towards soil transport and instability. In light of the recent development in the region, which has witnessed increased agriculture, the building of roads, leading to accentuated deforestation. Water that would be absorbed by forests and pastures now runs down transporting huge masses of soil and debris, depositing the same at various negative curvatures along the way down. Water movement on these surfaces also affects the texture of the ground making it lumpier and mixing rocks with them; making construction harder on such conditions.
Besides, predicting land failure, this data can also be used for various design based strategies on the landscape level. The models create are embedded within the cell-based grid system. Where these values ae utilised to factorize their contribution towards mass movements acroos the study patch. FLOW ANALYSIS
Analysis of hydrological flows has three primary categories: Flow direction, Flow Accumulation and Wetness index. Flow direction describes the possible paths from ridge to valleys, demarcating watersheds, while flow accumulation provides the inland drainage, identifying active stream networks within the region and lastly the wetness index, which provides all possible location on the patch where water has the possibility to accumulate.
F perm is the profile-permeability class factor (unitless)
Pclay is the percent clay (unitless).
A parameter based erosion model called USLE (Universal Soil Loss Equation) - developed by Wischmeier and Smith(1961) is seen as a possible method to calculate soil erosion quantities. Although the method is a lumped experimental model that does not separate factors that influence soil erosion, such as plant growth, decomposition, infiltration, runoff, land transport (Weltz et al., 2017). The USLE was designed to estimate sheet and rill erosion from hillslope areas (Renard et al., 1997). The equation was modified in 1997 renaming to RUSLE (Revised soil loss equation). Thus, the revised version is chosen, where the five top indicators are as follows:
K: Predicted average soil loss
R ( Req): Rainfall erosive factor
LS: Slope length factor
C: Cover and management factor
P: Conservation practices
The parameters R, K, L and S factors primarily influence erosion volumes, whereas P and C factors influence rate of erosion. The K and LS factors are varying with land use change( especially if you are building in certain areas because a change in the terrain is introduced disturbing previous values. C and P factors are directly linked with Land-use with each practice assigned a specific value between 0 -1.
OBJECTIVES
04-4.2
The erosion in the area of Leh-Ladakh, India is caused due to both snowmelts, thawing of soil and rainfall ( cloudbursts). Thus two distinct model were created:
(a) The annual model that considered the soil loss due to snowmelt and snow, the parameter R here was altered accordingly.
(b) Typical cloudbursts that examined the soil loss due to intense rainfall, the hydrograph from the Leh-flash flood(2010), was used to determine the R values( refer equations)
Once the core objective is realised (i.e. what scenario to target), the stated attributes above are calculated from the data generated previously from various factors(Refer equations). Once, the quantized data is collected. This information would be used to produce a weighted susceptibility mapping for the region. The same data would then be utilised to get deposition cells. A relatively smaller test patch will be chosen (to minimise the computational load).
Erosion Resulting from Snowmelt, Rain on Snow, and Thaing soil are considered as a major cause of erosion. The thawing of soil remains quite wet above the frost layer and is highly erodible until the frost layer thaws, to allow draining and land consolidation. The frost layer near the surface limits infiltration and creates a supersaturated moisture condition causing almost all rainfall and snowmelt to become runoff. For these circumstances, Req values are used rather than R factor.
R25 RUSLE Model Factor Maps
DYNAMIC WEIGHT ASSIGNMENT
BINARY INDEX OVERLAY
Physical attributes calculation,such as slope angle,slope elevation.
STATIC WEIGHT ASSIGNMENT
FITNESS CRITERION
EVALUATION
HIGH RISK
Risk Domain: 2.5 - 5
No. of cells: 7503
% of Total Area: 39%
Probabilistic susceptibility map
MEDIUM RISK
Risk Domain: 1.8-2.5
No. of cells: 7609
% of Total Area: 35%
LOW RISK
Risk Domain: 0.1 -1.8
No. of cells: 5070
% of Total Area: 24%
04-5
QUALITATIVE WEIGHTED ANALYSIS
Analysis of the test patch on the basis of soil erosion, slope gradient and debris flow.
WEIGHTED ANALYSIS
Previous Page (right top) : Fig| 04.25 Diagram showing high risk cell that are most probable to release soil throughout the year.
Previous Page (right middle): Fig| 0.4.26 Diagram showing high risk cell that would occasionally release soil during the year.
Previous Page (right bottom): Fig| 04.27
Diagram showing high risk cell that would rarely release soil during the year.
Previous Page (left middle): Fig|04.28
Diagram showing complete susceptibility map
Current Page (right top): Fig| 04.29
Graph showing various weighted option that were brute forced.
(Source for all: Author)
04-4.5.1 04-4.5.2
As R.U.S.L.E indicates the highest amounts of soil loss within each cell, it becomes possible to analyse areas where landslides are likely to occur, the factor maps created during initial steps were weighted iteratively and continously equated with the factors of the high soil release areas provided by the R.U.S.L.E model, until an equitable probabalistic function defining the constribution of the parameters to soil loss is obtained. The R25 model is used to determine the fitness as the model predicts soil loss for the most sensitive areas in cases of limited rainfall. This modified regression model (almost a brute force attack) calculates the deviation from the fitness map.
TECHNIQUE USED
Inside this regression model a technique called Binary Index Overlay method is used. Accordingly, each binary evidential map parameter Bi(i¼1, 2, …,n) is given a numerical weight (Wi) based on ‘expert’ judgment which relies on the importance of the geological features. These weights are positive integers or real numbers( in our case 0-5), where 0 (very unlikely) and 5 (very likely). In other words, each cell has its class of specific weight for a given parameter. In the final output map S, all the informative layers, of a pixel, were overlayed and remapped under a single domain preferably 0 -1. This Binary Index Overlay model is used for performing subjective-based analyses between the RUSLE model. The process is continued in order attain the most suitable contribution weight of each parameter to detect the most accurate promising areas (Refer Fig| 04.29, also Refer appendix to see various probabilistic maps generated in the process)
ANNUAL SCENARIO
YEAR 01
Release Volume(m3): 33074.34 Maximum Velocity(m/s): 3 Maximum Pressure(Kpa): 200
CLOUDBURST SCENARIO
Release Volume(m3): 45782.31
Velocity(m/s): 8
Pressure(Kpa): 345
10
Volume(m3) 62871.88
Velocity(m/s): 10
Pressure(Kpa) 428
Area(%): 73 Area > 6m deposition(%)= 23%
35
Affected Area(%): 89
Previous Page (top) : Fig| 04.30 All three images depicting RAMMS 10 year simulation showing increase in deposition heights
Previous Page (bottom) Fig| 04.31 Images depicting RAMMS result in case of cloudbursts, showing the deposition height, pressure and velocity.
Source for all: Author)
RAMMS ANALYSIS 04-6
Understanding the debris flow path and depostional patterns under various scenarios
OBJECTIVES
04-6.1
The aim of debris flow modelling is not to simulate the real events, but to quantize the erosive power throughout the rubble flow path. Thus the results are interpreted in a representative way rather than absolute. The other idea is to simulate debris flow that is typical for the study site, thus by altering certain parameters unique to a site one could apply this approach for various settings in the region. The generated data from this simulation is utilised to is to restructure the final synthesis map achieved from qualitative weighted analysis to produce the final structured risk mapping of all cells within the study site. We underline here that the Rapid Mass Movements (RAMMS) dynamical model (Christen et al., 2010), is used to simulate the debris flow and in particular to calculate the deposition of flow over the terrain. RAMMS numerically solves a system of partial differential equations, governing the depth-averaged balance laws for mass, momentum and random kinetic energy using first- and second-order finite volume techniques. In this work, the Voellmy–Salm approach is used.
METHODOLOGY
04-6.2 04-6.3
Two different set of simulations were created, firstly the one that calculates the seasonal deposition patterns over a set of 10 years; here the release areas from the R25 module is utilised, as these regions have the least resistance towards soil loss. Secondly, cloudburst soil release model is created based upon R100 (RUSLE model), a comparative is drawn between the two to understand the two scenarios for future design strategies.
A D.E.M (Digital Elevation Model) is created using coordinate interpolation within ArcGIS, acting as the base. for all calculation son R.A.M.M.S. Then cells prone to release the highest amounts of soil loss (from R.U.S.L.E) are marked as release sites to demarcate the flow of debris. Parameters such as density and A ten-year long simulation is conducted, resulting in various depositional sites along the paths. Effects of cloudburst on study site were simulated, through the data extracted from Leh,2010 cloudburst event; here the same hydrograph was fed as an input into the software with the following parameters:
Various release zones between 3450 and 3500 m (a.s.l.) were selected, with release height of 1 m and release volume of 333074.34 m3 (R.U.S.L.E results). Also, friction parameters µ and Xi were taken as 0.15 and 2000 m s−2, respectively.
INFERENCE
While the 10-year simulation indicates a gradual increase in deposition height till 6 meters, the flood scenario depositions reached 12m, showing a maximum velocity of 20 m/s but with great variation all across the site due to varying terrain and soil conditions. Also, a major increase in the affected areas were seen during flooding scenario. The outcome of these simulations indicates towards multiple strategy approaches since two different scenarios were being tackled.
RISK MAPPING 04-7
Generate the final risk map by re-integrating the new deposition results from RAMMS Analysis.
Current Page Fig| 04.33 to 04.35 Risk map, deposition map and deposition sites are shown as an integrated output resulting from combination of all previously generated mathematical models.
(Source: From Author)
MAX DEPOSITION
Total Deposition:1,964,693 m3
MEDIUM DEPOSITION
Total Deposition: 437,158 m3
LOW DEPOSITION
Total Deposition: 149,378 m3
HIGH DEPOSITION
Deposition range: 8.6 - 12.6(m) No. of cells: 1276 % of Total Area: 6.5%
MEDIUM DEPOSITION
Risk Domain: 5.3 - 8.6(m) No. of cells: 6788 % of Total Area: 34.6%
LOW DEPOSITION
Risk Domain: 0.2 - 5.3(m) No. of cells: 11578 % of Total Area: 58.9%
HIGH RISK
Risk Domain: 2.5 - 5 No. of cells: 5720 % of Total Area: 29.1%
MEDIUM RISK
Risk Domain: 1.8 - 2.5 No. of cells: 7485 % of Total Area: 38.1%
LOW RISK
Risk Domain: 0 - 1.8 No. of cells: 6437 % of Total Area: 32.8%
CONCLUSIONS 04-8
Inferences drawn from the study, to devise strategies for further experimentation and development processes.
LANDSCAPE INTERVENTION
04-8.1
OPPORTUNITIES
04-8.2
The analysis clearly indicates the dominance of integrating landscape based strategies; taking advantages of various multiple aspects of the terrain. As seen in the simulations, mass flows in the region have multiple aspects(flow,pressure and depositions) it became necessary to device possible strategies to tackle these attributes due to which sequential obstruction strategies are explored in the next chapter. Hydrological intervention is also based on the various factor maps and simulations results (such as soil release map on Pg:90)
The generated risk map provided a base for strategic planning and for further computation. The risk map is utilised as an index of positions for placing selective strategies corresponding to a certain risk domain on study patch. The corresponding factor maps were used as inputs in other design models, to determine building factor of safety and hydrological routes. The high and medium soil release areas (Refer Page: 92),were considered as major debris flow routes as indicated by the simulations;while the remaining areas were segregated due to their less course aggregate as possible water channels–first step towards hydrological strategy.
LIMITATIONS
04-8.3
One of the major limitation of this multi-sequence approach is the time scale. It consumed nearly two months (excluding data collection) to compute the most rudimentary data on our low-res models. As many different softwares were used, it was necessary to device techniques for data relay and representation , the process became even more tedious . A lot of other factors such as snow-pack run were not considered in susceptibility mapping.
As the generated design models rely on cell base (20mx20m) computation and evaluation, the data generated is not accurate but provides sufficient reference points for an in depth analysis. The size limit was imposed due to minimise computational loads.
RESEARCH DEVELOPMENT
Overview
Weighted Analysis
Modelling Retention Structures
Optimising Positions
Annual Phasing
Adding Dimensions
Wall Sequencing
Wall Statistics
Conclusion
Hydrology
Run-Off Model
Supply V/s Demand
System Logic
Locating Catchments
Increasing Efficiency
Conclusion
Land patterns
Timber Production
Food Production
System Logic
Landuse Patterns
Network Model
Growth Model
Conclusion
OBJECTIVES
05-1
OVERVIEW
An overview of the various proposed strategies towards a sustainable growth model
APPROACH OVERVIEW
This chapter explores various strategies which promotes settlement growth in these high altitude regions while addressing the issue of debris flow and food sustenance through emergent resource management techniques as an attempt towards a self-sustaining development model.
TEST SITE
A sequential approach was taken to determine the potential of the site. The basins (both debris and water) were considered as the initiators for all design interventions, as resource collection is set to be a primary concern for this environment. Food production and daily resources were also embedded within the system to delineate a comprehensive growth strategy for the site.
The Test Site considered for further research development is a 2.3 km2 of hillside region situated towards the north-west side within the study patch (9.0 km2). According to the analysis conducted during the previous chapters (Refer Site Synthesis) this area gains the highest deposition and soil factors from the entire region.
OBJECTIVES
While strategizing for any design intervention, seasonal changes and time were considered as a major contributing factor. Some of the primary goals were to limit mass flows to certain areas only, then collect and sort the same. Moreover, to develop a system which utilises these flows for terra-forming. Also, water being the most essential of resources within the ecosystem was dealt with, while taking physical transformations (from water to ice) into consideration.
ANALYSIS
LIMITATIONS
The analysis conducted in this chapter are of two primary categories: First, stochastic calculations were made to understand potentials of the site at the most primary level, for, e.g., sustained population, food production. Second, algorithms were designed, where parameters were altered to optimise towards various multiple conflicting fitness criteria( such as soil loss, increased food production, increase population density). While the first approach provides a basic understanding, with discretized numbers, it is the second method that provides any design assemblage to the whole logic. Regression analysis is considered ( where we attempt at monitoring production of resources and development under a viable limit) to understand the effect of time and how do various parameters alter given the due course of time, this helped develop a growth model for the analysed settlement.
The region affected the most in the risk analysis is considered as the Test patch for further development. The patch is a rectangular plot of land with dimension and area 2.3 sq-km. Since all calculations were done on a patch of 2.3 km2, the limitation of the scale was applied to the growth model, primarily to shed computational load.
05-2
UNDERSTANDING MASS FLOW ON SITE
Assigning weights to flow lines in-accordance to the velocity and pressure patterns on the test patch
Flow directions maps generated during site synthesis
Flooding pressure maps were used to assign weights to flow lines
OBJECTIVE
Soil Loss Maps coupled with slope angles
Before any initiation of strategy planning, a base understanding of the most likely routes and velocities of debris flow was prepared. In this section, a relationship is established between all flow lines and debris flow. Flow lines originating from every cell were weighted to carry out further design research.
i=0
j=Ne
∑ Wt[i] = ∑ (Rp + Rv + (A - (0.2 * A)))
j=Ns i=1
[i] = each segment of the flow line (divided between each cell)
Rp = Pressure value of each cell (taken from RAMMS)
Rv = Soil velocity of each cell (taken from RAMMS)
A = RUSLE soil loss value (20% deposition is considered, i.e some soil would be lost while in motion)
Ns = Index number of start cell
Ne = Index number of stop cell
METHOD
As all flow lines follow their distinct gravitational route dictated by the topography, it passes through many cells before coming to rest over convex or lowest most points in the valleys. The high soil yielding cells are bound to release more soil as compared to other cells; that would fall to different pressures and velocities in accordance to the slopes. Thus a weighted approach was considered for stratifying the water flowlines from debris flow lines.
Primarily RUSLE values and RAMMS pressure and velocity maps were utilised to generate a weighted mapping; which determines their debris carrying probability. Due to the complexity of the terrain, every flow line passes through multiple cells. Thus an equation was formulated where each cell is considered as a final destination and 10 -40% deposition was examined on each cell, depending upon their slope index.
The high soil yielding (probability) flow lines are represented as a colour gradient, while the grey line represents mostly water ( or low soil yielding) flow lines. This data can further be iterated to develop landscape-based strategies within the test patch.
Previous Page(top): Fig| 05.03 Four diagrams showing flow lines, RAMMS analysis results and risk map for the extracted test patch.
Current Page: Fig| 05.04
Diagram depicting various weighted flow-lines, colored lines are the probable debris flow lines and the gray lines are primarily water with small amount of sediments. (Source for All: Author)
High Probability of Debris Flow
Hydrological flows with low sediments Low Probability of Debris Flow
Fitness Base Inputs
RAMMS PRESSURE MAPS
Flooding pressure maps were used to assign weights to flow lines
RAMMS VELOCITY MAPS
Flooding velocity maps were used to assign weights to flow lines
RUSLE SOIL LOSS
Accumulative soil transfer from one cell to another was considered to derive an equation of distribution
RISK MAP
Overall risk map generated from binary overlaying of synthesis maps
Parameters
WEIGHTED FLOWLINES
The flow direction was assigned values based upon the velocity and pressure
CELL LOCATIONS WITH CONVEX SLOPES
The edges of the cells were the propagators of these structures.
RISK VALUES
The edges of the cells were the propagators of these structures.
Valley
ELEVATION OF STRUCTURES
Maximise altitudinal variation between retention structures
DISTANCE BETWEEN STRUCTURES
Maximise horizontal distance between two or more walls from the same loop
FLOW DIRECTION
Slope aspect and slope direction based flow direction from each cell were generated inside a computational envionment
No. OF FLOW LINE INTERSECTIONS
Maximise intersections with debris flow lines with minimum wall count.
05-3
MODELLING RETENTION STRUCTURES
A strategy to reduce impact of mass movement on the valley floors and minimise talus formations.
Current Page (top): Fig| 05.05
Depicting villager of Leh-Ladakh (Himalayan Village) building check dams with random rubble masonry.
Overall logic diagram depicting the work flow during debris placement strategy.
(Source : Author)
OBJECTIVE
The aim of this experiment was to collect the soil loss on the hills through retention structures, the material collected within these basins would act as sorting sites, that would allow for the further material for construction of new retaining structures and also provide material for building dwelling units. The experiment was set up as a genetic algorithm that allowed for emergent structures to pop- up based upon proximity and terrain parameter based rules.
METHOD
The previous data sets synthesised during (Chapter 4) were used during these experiments (Refer Fig:04.28). As flow, lines pass through many cells with each having their individualistic characteristics. A weighted distribution was applied to flow lines, to optimise the position of the retaining structures for higher material yield. The propagation of structures was evaluated through three fitness criterion’s namely the heights from which they emerged, the number of flow lines they intersect with and the distance between each wall. (Refer Fig 05.06). The performance of every structure was recorded to calculate the performance index for one generation where the objective was to maximize the soil collection from the minimum number of walls. This systemic approach provided the initialization towards an integrated design output. The importance of this retention is paramount to collect the soil from various locations and relieve the valleys from future depositions.
05-3.1
05-3.2
Current Page: Fig| 05.07
Diagram showing the final individual selected from various GA results.
Next Page (top) Fig| 05.08 Graph showing the performance index of the best individual from every 150 generations.
(Source for All: Author)
Lines that do not interact with the structures
All lines within color range are the flow lines that intersect with the gabions
05-4
OPTIMIZING LOCATIONS
Placing retention structures on site with respect to the various terrain and debris flow aspects to extract the maximum performance.
OBJECTIVE
05-4.1
For the structures to be effective on site; location becomes one of the primary factors, which is an outcome of various terrain and debris flow factors. The aim of this experiment is to optimise the positions of the desired retention structures, based upon the criterion’s discussed on Page: 104. These structures provide the possibility of relieving the valley areas from major depositions; providing opportunities for agricultural andsettlement growth on flatter plains.
METHOD
05-4.2
A genetic algorithm was created to populate the site the with structures, and performance index for structure was calculated with the following formula (Refer text on left). The performance index along with the criterion’s explained on the previous page help evaluate the fitness of each individual. The graph above depicts the evaluation for the fittest individuals till the 200th generation which comprised of a population of 20 individuals in each generation. A progressive escalation in the performance was observed during the initial phase of the experiment, but manual adjustments had to be made in the script when the pattern of the structures began to become more sparse, thus the Octopus “explicit” component was used, that allowed for the manipulation in the values.
x = Total number of walls
Xd = Intersections with debris flow lines
Xw = Intersections with water flow lines
Rd = Remaining debris flow lines
y = Total number of lines intersected
INFERENCE
05-4.3
The fittest individual is selected from the 150th generation in accordance to the amount of debris collected and the performance index. But, as the approach is just an indication of fluid dynamic rules, the experiment voids any consideration of dynamic deposition distribution between structures build along the same flow lines. Thus regression modeling was adopted to quantify amount of soil retained under each gabions sequentially built progressively for 10years.
SOIL COLLECTION- ANNUAL PHASING 05-5
Quantifying soil loss through 10 year (modified form of) regression analysis.
Previous Page Fig| 05.09
Collection of diagrams showing yearly propaga-
tion of walls along with various deposition areas.
Current Page(right): Fig| 05.10
Graph depicting the analytics of final sequence taken forward for further design.
(Source: Author)
No of Walls Built
i*100
Current Debris Volume
i*1000
Cumulative Debris Volume i*10000
OBJECTIVE
05-5.1
Since the results of genetic algorithm only provided the final locations; without any consideration to construction time it became necessary to develop a progressive sequencing for building these structures , while taking into account nominal working hours, distance and material required to construct.
METHOD
05-5.2
Sequences were crafted based upon material collection by individual retention structures. Thus adequate material collection for new future walls were considered as the primary factor while setting the sequence. Also, due to harsh working climate, a minimal of 5 working hrs/ person were considered for 6-8 months; as working outside in winters is not possible. It was estimated that in any given scenario we cannot build more than 12 walls /year considering a workforce of 15-20 people working year around. These set rules let to a desired sequence, which was taken forward for further analysis.
INFERENCE
05-5.3
This analysis was of paramount importance as resource demands are always expected to rise with population. The quantized parameters did not consider the amount of material that would be required for constructing and repairing these walls each successive year. This sets the precedence for our next experiment, which provide us with accurate numbers of the balance material, once the above parameters have been taken into account. The images on the following page shows the difference in deposition in the two scenarios both – with walls and no walls. A 79% reduction was observed with large areas in the valleys cleared of depositions.
No Retention structures
Current Page: Fig| 05.11
Deposition scenario after 10 years with no wall. Gradient depicting high to low levels of deposition. (Source: Author)
Back batter
Random Rubble Masonry
Previous Page (left top) Fig| 05.13
Data table showing the various attributes of both random rubble and masonry walls.
Optimizing the dimensionality of retention structures from site variables.
DESIGN LOGIC
05-6.1
The design of retention structures is highly dependent on the estimation of load and effective contact pressure. During this procedure, the lateral debris pressure was considered as primary forces affecting the retention structures. Using Rankine’s formula, the heights for each retaining wall were calculated. This provided an estimate for sediment deposition under variable pressures; as generated during debris flow synthesis (Refer Chapter 04). The base width being a multiple of the height (H) is recorded accordingly. Thus, all walls were structurally optimised to counter and minimise the flow impact of subsequent walls on lower slopes.
P = γs H2 (1 - sin ø)
2(1 + sin ø )
P = pressure in kg/m2 (the pressure acts at H/3 above the base [DSCWM 2005])
H = height of the wall in meters
γs = density of the soil in kg/m3
ø = angle of earth in degrees
SORTING MATRIX
05-6.2
Sorting matrix describes the various levels of material size (ranging from 300 mm to 0.5 microns) in a debris flow environment. Since it is fundamentally impossible to find the percentage of each size range, a generalised logic was established, where probabilities of various size of rocks to occur was delineated from soil texture maps during site synthesis. The matrix provided evaluations as to how much of particular type of material would be available during soil collection. These established rules would help in distributing material of various sizes more equitably.
METHOD
05-6.3
The aim of installing retention structures is to harness the availability of building material and utilise it with minimum automation, to achieve maximum stability and safety against sliding or overturning, the wall height and slope degree become the primary drivers for determining the wall type. To minimise consumption of material to construct retention structures, the structures were stratified into gabions and random rubble masonry walls, based on their performance, permissible stresses and slope parameters. This was seen as an opportunity to combine gabions with rubble masonry as a possible method of controlling excess demand of building material, thereby reserving maximum size boulders for random rubble masonry and the lower grade stones for gabions. Gabions with their reinforcement are more rigid and require less automation than stabilised earth or stone walls (Anniamma et al., 2015). This provided a 48% decrease in smaller size stones (50- 100mm), these stones can be utilised in transforming landscapes or even walls for units, thus increasing the overall redundancy within the system.
WALL SEQUENCING 05-7
Sequencing wall deployment on a ranking system based on debris volume and walkability distance.
MATERIAL MANAGEMENT
05-7.1
Previous Page (complete page) Fig| 05.16
Diagrams depicting sequential progression annually for 10 years.
(Source: Author)
Current Page(top) Fig| 05.17
Sequence of walls for year 1, depicting various deposition and walkability radius.
(Source: Author)
Once the rate of consumption, segregation and extraction of soil was established, an annual building strategy for 10 years was formulated. Since the number of walls appearing annually was already established during the phasing analysis (Refer Pg:108), the sequencing decisions were based upon the following considerations: Walk-ability and elevation of walls where a walkability radius of 600 m was considered as an acceptable threshold for transport of material. Also, the elevation at which the walls were situated would increase the construction and material transportation time. Thus walls lying at similar elevation on the terrain were constructed first. This led to a sequential proliferation of walls over a period of time. Once this was achieved material consumption and soil gathered volumes were recorded for each year (Refer Fig| 5.16).
Random Rubble
Gabions
Current Page Fig| 05.16
Rendering of test patch with gabion and masonry walls (Source: Author)
Width of walls
Height of walls
WALL STATISTICS 05-8
Quantifying soil loss through 10 year regression Analyis
Width of walls
DIMENSIONS
To control and collect soil loss a total number of 103 walls were estimated for construction where the maximum height reached by the retention structures was 8.0 m and a maximum base width was 3.6 m. Also the highest depositions were recorded in the 5-7th year, indicating towards maximum material collection during the following year. Also,the final estimation of material consumed vs collected witnessed a reduction by 43%, when considering a combination of gabion and rubble masonry retention structures. The following section discusses the degree of success and limitation of the experimentation.
Current Page(top) Fig| 05.17 Graph depicting the height and width of the gabions (Source: Author)
Current Page(bottom) Fig| 05.18 Graph depicting the deposition on each wall (Source: Author)
05-8.1
05-9
CONCLUSIONS
Inferences drawn from the experiments, delineating further experiments and development processes
SYSTEM POTENTIAL
05-9.1
The proposed system is evaluated upon the total amount of the soil loss that is collected by these “pop-up structures”. The system shows a variable efficiency ranging from 68- 83% (Refer fig. 05.07) of the total soil loss collected over a span of 10 years. Tackling the residual volume, sets the potential precedence for a set of future strategies. The volume collected can be sorted and utilised for various functions, such as slope stabilisation, constructing catchment surfaces, dikes and building unit dwellings.
POPULATION ESTIMATION
05-9.2
The material collected can be used for population estimation within the test patch. A typical unit size of 5 x 5m with 3m high is considered (delineated from various settlement studies) as a base for quick volume based calculations which shows that a total of 13,000 units can be constructed within a span of 10 years. Considering each unit is single storey and is occupied by four people (average family size in the region) a population of 52,000 people is possible. Although, this does not take into account any food or water consumption and is purely based on construction material consumption for a unit. Considering these valleys are not high density the remaining material can be utilised as a trade-able commodity with other villages in return for food and other goods. The limitation of the system is the constant wear and tear that the walls
Previous Page (top): Fig| 05.20
Current Page(top) Fig| 05.21
(Source: Author)
LIMITATIONS
05-9.3
would experience and would require regular maintenance and timely inspections. Also, construction is not easy in this part of the world, due to climatic concerns. Although minimum automation and quantum of construction have been attempted keeping in mind the above factors, the laborious work of moving stones on a hilly terrain is extremely taxing.
Also, the sorting matrix estimation, which informs about the grade of soil mixture collection is highly generic. A more elaborate study needs to be done to demarcate zones, according to the sizes of rocks and soil texture in each zone.
The strategy completely relies on community efforts for sorting, transporting and construction of these retention structures, where the people will have to be trained or made accustomed to the various process involved in the construction assembly of these walls. Finally, the construction of gabions require wire mesh cages , which were not considered during estimations for structures. But these extra items can easily be purchased from lower valleys of Kashmir, which is a days trip from the valley of Leh.
North-side rendering of the test patch showing gabions and masonry structures in th landscape during a summer scene
(Source: Author)
North-side rendering of test patch showing gabions and masonry structures in th landscape during a winter scene
Previous Page (top): Fig| 05.23
A typical conservation pond in Ladakh (Source: http://www.ecoideaz.com/wp-content/ uploads/2016/04/Artificial-Glaciers-Chewang-Norphel-7-1024x576.jpg)
Previous Page(left bottom) Fig| 05.24
Shows a dried up water catchment system, due to wrong placement of walls (Source: http://climateheroes.org/wp-content/ uploads/2014/08/ClimateHeroes-ChewangNorphel-7-1030x686.jpg)
Previous Page (right bottom): Fig| 05.25
An artifical glacier in ladakh (Source: http://glacierhub.org/wp-content/uploads/2016/08/DSC_0080-e1471888554949. jpg)
SEASONAL SHIFT
HYDROLOGY
Understanding the hydrological cycle and various other parameters to develop strategies for a stable hydrological productivity
Seasonal shift in these high altitude regions has a transformative hydrological cycle; from streams filled with glacial melt in summers to snow covered mountains in winters (Refer Fig on previous page). The success of present strategies implemented has been low, due to lack of knowledge (especially placement of catchments, understanding of topography). The strategy was to use previously generated computational knowledge and utilise these seasonal alterations in combination with the topographical opportunities.
STRATEGY
Collection of glacial melt and surface run-off from hill slopes was given primary importance; catchments were strategically distributed across the test site to ensure maximum collection and distribution; this was achieved through interpolating topographical data with natural water routes. Dikes were created using earth fill material to channelize the snow melt run-off from slopes into these catchments (through the intersection of least resistance paths between dikes and flow lines). Also, catchments surfaces were located at higher elevations, which would catch excessive snow and divert flow directly into the catchments. As the local farmers work only during day hours, the evening glacial melt usually gets discarded. Secondary collection catchments are created in the shadow regions to ensure excess water collection, where these catchments can be recharged during summers and frozen during winters. This frozen water would be utilised during summer season or in times of high demand.
METHOD
A run-off model was created to establish an understanding of the amount of water flowing through the test site. Glaciers and snow pack run-off modelling was done using Martintect's run-off equations. Experiments were set up using topographical and climate models, extracted during previous chapters. Agent-based modelling is synthesised within a continuous looping algorithm that helps find the optimal positions of the catchments and least resistance paths for dikes. The individuals were evaluated by the amount of water collection, distribution and material used for construction.
Glacier position on site
Glaciers affecting Test Patch Test Patch
Previous Page (top): Fig| 05.26
Snow Pack modeling of the test patch indicating variable snow depths
Previous Page(bottom) Fig| 05.27 Terrain model illustrating location of all glacial sources affecting directly/indirectly the test patch.
Current Page (right) Fig| 05.28 A graph representing the annual run-off rate for different periods of the year.
(Source for all: Author)
RUNOFF MODEL
Discretized approach towards understanding the snow melt discharge for optimised catchment positions
Any drainage system is designed keeping in mind the topography and the quantity of run-off per season. Many factors from heat transfer equation, snow-melt factors, soil texture and permeability to differential air temperature patterns are considered to develop a run-off model. In this region precipitation is usually received in the form of snow,( which is >150mm/yr) during the months from October-May, and the melting primarily happens from May -September, The seasonal streams formed during summers are different from the glacial melt that flows regularly throughout the year.
The snow-melt equation provided by Martintec,1975 is used to determine the quantity of run-off on the site. As the snow fall varies with elevation , the site is divided into 3 zones and snow covered area are determined through image processing of various satellite images from Arcgis. Air Temperatures are extrapolated through Ladybug plug-in within grasshopper (an alternate source could be metronome). The “P” factor is taken as minimum (0.03), as precipitation in the form rain is minimal. Degree day “an” factor is calculated through (1.1 * density of snow /density of water). The recession coefficients– daily melt water production that appears immediately in runoff, flow accumulation factors were utilized to delineate factors for each zone. The factors were determined for melting period(summers) on monthly basis. This data was utilised in the succesive sections to determine catchments depths and locations.
Glacial Melt + Snow Melt
Glacial Melt
Glacial melt
SUPPLY V/S DEMAND
Understanding the seasonal demand and supply scenario in-order to formulate collection and distribution strategies. 05-12
SPRING
The demand of water is the highest during this season, as tourist influx and agricultural activities are at their peak. The artificial glaciers continue to shrink away with rising temperatures each day. As these glaciers are nearer to the settlement, the farmers can utilise these waters for early morning irrigation, which is not possible when relying on natural glaciers as they take time to flow down to the valley reaching only after the noon time.
SUMMER
Increase is demand is seen due to the beginning of tourist and sowing season, adding dependency on local water sources. The inlet valves of the secondary channels are barricaded and the outlet valves are opened for the fully matured artificial glaciers (that were frozen during winters ,as they lie in shadow region) to release melt water providing sufficient water for consumption and daily demand.
The demand subsides during these months , although the supply from the melting mountain continues to flow down to the valleys. Thus the secondary inlet valves can be opened and the outlet can be barricaded. allowing secondary catchments to be replenished with water again to be recharged during this period.
The water demand is recorded to be minimum during these months as people require water only for daily needs like cooking, bathing etc. A drop in the melt water from the natural glaciers is seen as mountains peaks are under subzero temperatures. In these low temperatures the secondary catchments ( present in the shadow regions) receive minimum solar radiation and begin to crystalise into ice forming artificial glaciers.
AGENT BASED APPROACH FITNESS
INPUTS
05-13
SYSTEM LOGIC
System diagram describing the progressive logic for integrating various hydrological strategies
Volume of Water
Number of Catchments
Spread across site
Evaluation
STAGE-I
Optimizing catchments positions
Surface cells
Cells Slopes
Cells sunlight hours
Surface cells
Cells Slopes Gradient
Flow Accumulation
Optimising catchments size
Travel Maximum Distance
Maximum intersection with flow line
Maintain a high gradient Rise
Avoid collision with gabions/change vector
// Find the lowest convex point
// Generate 4 agents with the following rules
// Find 4 different distinct paths within a given domain of gradient
// check for intersection with any flow line
// if staisfied move to the next point
// if intersection= null kill agent
// Repeat steps till life
// life of an agent is dependent upon the intersection along its path and the gradients it walk on.
Increase in Volume
Material required to Built Dikes
Decrease in Catchment Area
Evaluation
STAGE-II
Increase in Volume
Number of Changes to Slope
Material Required for stabilisation Evaluation
Adding Catchment surfaces
Catchmentsurfaces
Surface cells
Cells Slopes
Cells sunlight hours
Flow Accumulation Data
Flow Direction
Optimising catchments size
Cell Curvature
Cells Slopes
Flow Direction
Water Flow Lines
// Find nearest neighbour with the highest convexity
// Check for radiation conditions
//if yes, generate route through looping succesive gradient route
// Find the best fit cell, Rpeat step for all catchments
// Find all cells intresections with flow lines
// Find Neighbours for every cell
// Find angle between Catchment cell and present cell
// Find the difference in the alignment angle
// If Angle difference is > 100 change angle
// Repeat steps and record supplelemntary angles
// Record all cells draining into the catchment
Catchment cells
Altered Directions
Un altered Directions
Proximity to Catchment
Material required to Built
Total Sunlight hours on Cell
Evaluation
The whole algorithm was carried in two steps where Stage-I was an entirely separate algorithm and Stage- II, III, IV were clubbed together. While Stage-I provides with actual positions for catchments the latter stages optimises the efficiency and adding additional redundancy to the system; the secondary catchments are like ponds that can be recharged during winter months and frozen and can be utilized during summers for agriculture and daily use.
STAGE-IV
STAGE-III
(Source: Author)
LOCATING CATCHMENTS
Generating catchments across the test site, while optimising for maximum collection with minimum number of catchments. 05-14
OBJECTIVE
05-14.1
The primary objective is to distribute catchments in-order to collect and distribute water across the test site. Catchments were to be placed strategically, taking advantage of the convex landforms found across the site. This was done to maximise the hydrological collection with the least number of catchments required to distribute water all across the site.
METHOD
05-14.2 05-14.3
The basic concept diagram (Refer page134) describes the stage-1(i.e. locating catchments) of the strategy. The curvature and slope gradients data generated during chapter four (Refer site synthesis) were used as inputs to progressively rate the cells within the algorithm. Cells selected as catchments were constantly made to come closer and fuse through proximity and collision calculations. This helped in clubbing multiple catchments together.
In-terms of water collection, each flow line was weighted based upon the run-off model generated previously (Refer Pg:126). Intersections between the flowlines and the catchments cells determined the volume of water collection inside the catchment; cells were color coded accordingly w.r.t their volumes.
INFERENCE
The algorithm did perform as intended, the progression has been documented on the following page (Refer page;130). The individuals clearly shows the proliferation and fusing process between cells. A total of 190 cells (cell size 20x20m) were considered as final catchment cells. The depths for these cells were calculated accordingly as per the estimated water collection volume. The final catchment positions showed an efficiency of just 57%, thus another approach was considered to increase the efficiency of these catchments through catchment surfaces and dikes. This sets the precedence for the next stage of strategy implementation.
(Source:
INCREASING EFFICIENCY
Increasing efficiency by diverting residual flow towards catchemtns also, generate secondary catchments to collect extra water during winters.
OBJECTIVE
To increase the water collection by channelising non-diverting flows towards catchments and generate catchments surfaces, such that they collect fresh snow during winters, which melts and flows directly into the designed catchments.
METHOD
The agent-based simulation was set up, where multiple (10)agents originated from catchments, through rules (Refer page 127) agents moved towards high gradients and chose a direction based on the preferential analysis (highest gradient), where the agent had to intersect with the non-diverting flow lines as transversely as possible. The life span of the agent was only for one iteration, where it could make only make a single move. The paths constructed by the agent were weighted based on the distance travelled and a number of flow line diverted towards catchments. Only one path was taken forward, and the rest were discarded, and new agents were generated from the end of the path. The process continued until the maximum number of intersections were achieved. An inbuilt collision control algorithm was constructed to avoid intersections with the retention structures.
Simultaneously, another set of agents were generated from higher elevations that modified their paths to flow directly into the catchments. The paths from various agents were weighed based on distance travelled and a number of changes made to their paths. The main aim was to minimise the distance and reduce the number of changes to the path. Catchment surfaces were constructed to facilitate water flow along the final route.
INFERENCE
The experiment increased the efficiency of the catchments from 57% to 93% as the dikes were diverting flows towards a more confined area; reducing the size of the catchments. Catchment surfaces were provided acted as extra water holding facilities. Since many catchment cells became redundant, cells lying the shadow region were chosen as secondary catchments. These catchments would become active during low demand period and due to the low temperature ( as they lie in the shadow region) would freeze into artificial glaciers.
of the fittest individual from agent based modeling experiments (shown on following page).
SUMMER TRANSITION
05-16
CONCLUSIONS
Discussing the potentials and limitations of the system.
WATER CYCLE LIMITATIONS
05-16.1
05-16.2
The combined result of the experiments resulted in an integrated and interconnected system of primary, secondary catchments, dikes and catchment surfaces was developed which modifies the way it operates based upon seasonal demands and variable flow range.
During spring when the demand is at its peak, as many tourist and local return , and sowing season is just beginning. Th primary catchments hold large quantities of water, supporting principal activities during day time. The trend continues as the gradual increase in demand is seen, due to increase in transient population and agriculture activities. The supply from a glacial melt that flows down in the evening is now stored in the catchments. Thus there is the availability of water early morning.
During Autumn, water demand subsides as tourist and agriculture practices drop, while the supply from the glacial melt continues to flow down.The secondary catchments become active and begin collected water. This water being in the shadow areas transforms into ice and mature as artificial glaciers during winters. These glaciers melt during spring-summer season, and this water is diverted back into the primary channel, thus balancing the supply and demand equation.
As, the catchments show seasonal variation, the surfaces and dikes created during the second stage ,provide extra water. During winter snow collected over land and catchement surfaces, the run-off from this snow, is directly diverted into the cathcement.
The process of obtaining an integrated hyrdological system was only possible because of the data set generated during all the previous chapters. Also, due to lack of available data, a better data-set from Metprograms such as MODIS and ENVI, can yield closer to more accurate results. The cell based approach again is limited to its boundaries and is non-scalable, due to computational loads. Thus it would be difficult to apply this strategy on a larger scale.
Previous Page (top) Fig| 05.36 Actual site photograph showing community based effort in making water irrigation channels from artificial glaciers to ensure higher rate of distribution.
Previous Page (bottom) Fig| 05.37 Many volunteers from global exchange programs and NGO's contribute in improving the current scenario on site. Installation of wind barriers and snow fences is seen in this image.
Investigating various localised strategies through native tree and crop sampling to minimize recurring soil erosion and generate emergent landuse patterns.
INTRODUCTION
The integrated strategies of stabilising debris movement and gaining control over hydrological patterns through requisite experimentation reduce the ongoing pressures of resource procurement in the region. Since the annual phasing of retention structures and seasonal transformation of water resources is a periodic event, it is necessary to devise an emergent land use strategy that can be focused on these events and predict the viability of maximum population that can effectively depend on the production and consumption of these resources.
As the region is subject to continual soil erosion due to increase in surface run-off and slope instability, this consequence is seen as a potential to devise possible land use patterns within the test surface. Study of native tree-crop sampling and their effective root zone depths accounts for the reduction in slope failure at the same time providing a scope of generating timber stockpiles and year-round food resources.
The critical threshold of population inhabitation is dictated by the balance created between resource logistics and erosion control strategy. This inter-relationship is defined by the rate of deforestation and crop harvest period. The rate of deforestation is directly proportional to fuel consumption by the target population which, is comparatively higher in winters than summers. The crop harvest period limits the span of food availability, beyond which the growth model is likely to depend on external sources.
The system is evaluated on a multi-parameter index which is a cumulation of various preset domains. The aim of the experiment is to observe the shift in the balance between population migration and resource extraction to record the maximum extent between the two entities. The land use pattern is generated keeping in mind the long-term impacts of vegetative overgrowth on the soil texture. As the terrain is embedded in a cold desert biome, it is important to acknowledge the subtle nuances unique to the environment.
TIMBER EXTRACTION
A forest cover strategy that serves the dual purpose of maximising wind erosion control and firewood productivity.
Poplar (hybrid) Willow Juniper
Base width (girth) : 0.25 to 0.65 m
to 40.0 m
Soil Loss Coefficient: 0.009
Maturity Span: Temperature: Spacing c/c: 0.9 to 1.2 m
Base width (girth) : 0.3 to 0.6 m Root Zone Depth: 1.0 to 3.0 m
Soil Loss Coefficient: 0.009
c/c: 0.3 to 1.5 m
Base width (girth) : 0.8 to 1.2 m Root Zone Depth: 0.6 to 2.5 m
Soil Loss Coefficient: Maturity Span: Temperature: Spacing c/c: 0.6 to 1.0 m
PERIODIC STOCKPILING
05-18.1
n = (z/4)*dt
a2*k(πr2h)*s
z/4 = no. of families within estimated population density
d = daily consumption [m3]
t = annual consumption period [days]
a2 = area of one cell [sq.m.]
k = rate of deforestation [%]
πr2h = volume of singular timber section
s = tree spacing [c/c]
FUEL
05-18.2
Since firewood is an annual requirement to support daily activities like cooking and heating, a system of periodic stockpiling is adopted by the locals due to extreme temperatures and prolonged distances. An opportunity of minimising the distance of acquiring timber and maximising localised stockpiling is seen as the primary driver of locating forest cover. However, the location is further optimised on the levels of slope gradient, elevation limits and growth cycle.
The daily requirement of firewood per capita is considered to be an average of 1.0 to 2.5 m3 depending on the surrounding temperatures and elevation at which the unit is located in. Experiments are set up using topographical and climate models, extracted during previous chapters. A generative algorithm with the objective of minimum soil loss and maximum timber production is developed to generate quantifiable data that would define the ratio of fuel consumption to production .
The balance between consumption and production can only be achieved by controlling the rate of deforestation as this would have a significant impact on the soil condition and growth cycle of the forested area. Deforestation accounts for the maximum number of people that a forested area can possibly support and this proves to be crucial in controlling the forestation coverage. A mathematical equation to equate the deforestation rate with subsequent tree number was further developed as a part of the evaluation process.
Previous
Current
Slopes above 350 Heavy afforestation to reduce directional movement of soil along steep slopes
Slopes 30 to 350 Heavy terracing and closely planted poplar hybrids with deeper root depths
Slopes 25 to 300
Terracing strategy for alternating winter and summer crops on multiple contour intervals
Slopes 20 to 250
Intercropping with slight variation in plant type
Slopes 10 to 200
Intercropping strategy of alternating summer and winter crops and willow growth
Slopes 0 to 100 Pastures in summer and short rooted shrubs as winter vegetational growth
DISTRIBUTION LOGIC
05-18.4
The distribution of native trees across the test surface is segregated on the basis of different slope degrees and the soil holding capacity of root depths. Various strategies of intercropping and terracing depending on the intensity of failure plane are adopted to ensure maximum slope stabilisation on steep terrains. Since, cattle rearing is a common traditional occupation, indigenous grasslands and winter vegetation with fibrous root types are positioned on flatter slopes to minimise surface erosion. The trees sampled have various attributes that complement different aspects of the environment, be it temperature variation or effective spacing density. These attributes dictate the maximum number of trees grown to promote rapid maturity and longer survival.
The experiment strives to maintain cluster growth of forest groves to avoid isolated patches which would be redundant over a period of time. The strategy of integrating both agriculture and forestry into a unified concept thereby ensures equal accessibility to both timber and farmlands from proposed building sites.
Page (top): Fig| 05.38 Native tree sampling done on-site, showing poplars, hybrid and elms trees (Source: Author)
Page (top): Fig| 05.39 Slope failure diagram; suggesting alternative means of engaging control over the failure plane.
Source: Redrawn from Danjon, Barker, Drexhage, Stokes (2007)
05-19
AGRICULTURAL PRODUCTION
An agricultural strategy devised under the aim of maximising annual food production and storage in the region to sustain effective target population.
(Source: http://ladakhsummer2009.blogspot.co.uk/
Next Page: Fig| 05.41
(Source: Author)
INCREASING
GAP
SITE FACTORS
The difference in personal economic growth from agriculture as opposed to tourism is considered to be almost negligible by the locals. Agriculture has thus been on the decline due to conversion of arable land into commercial and residential areas. The Department of Agriculture has initiated various programs to maintain the production by giving 50% subsidies to machinery and infrastructural setup.
The lack of response from the locals is primarily due to mediocre water supply in winter and higher rate of evapo-transpiration in summer. The rate of evapo-transpiration directly affects the cell growth of the vegetation. Thus in order to achieve the best natural growth of any crop, the water resources should be in closer proximity to the fields, or nearly equal to the rate of evapo-transpiration. All crops have their unique growth and yield rate, thus crop rotation or inter-cropping can be used to increase resource production.
Leh has extreme elevation differences over short distances that directly affect the crop calender, leading to diverse cultivation practices. The economical shift from barter to monetized marketing has also impacted the change of cultivation patterns. Farming of exotic vegetables along with traditional cereal crops demands additional water supply. The water allocation system in Leh does not correspond to the spatial organization of crop water requirements thus leading to compromised annual production.
The implementation of passive solar greenhouses is a recent development in the region which strives to ensure stability of seasonal and off-seasonal agricultural production in the winter months thereby reducing food security issues to a significant extent. However, the setup demands adequate knowledge of the surrounding terrain, solar access data and building material.
Current Page (right): Fig| 05.40
Community run greenhouses in Ladakh; provide for both agricultural produce and recreational spaces.
Diagrams representing agricultural strategies to reduce soil erosion on different slopes.
REVERSE SLOPE TERRACING
D: Vertical drop
R: Horizontal displacement
W: Terrace width
d: Cut depth
h: Rise horizontal distance
S: Natural slope (%)
INTER CROPPING
SYSTEM LOGIC
Multi-level Genetic algorithm, to create balance between production of resources and population density, while optimising towards higher solar access and reducing soil loss in the region.
Pre-calculation phase
Catchment cells
TEST SURFACE
CONSTANTS
Constants are carried forward as proximity attractors that allow for cell program distribution
Catchment- surface cells
Cells Slopes Gradient Solar Radiation
PROXIMITY ATTRACTOR
Predicts a cumulative factor for each cell, calculated through distances of the cell from each closest constant type.
Factor Generation/ Assessment phase
PERFORMANCE MATRIX
SLOPE DISTRIBUTION
Debris material collection cells
REMAINING CELLS
CELL TYPE DISTRIBUTION
Assigns a function to each cell, the three functions being, agriculture, building and groves.
Function classification
Based upon weighted factor the cell types are further segregated into different sub functions
WEIGHTED FACTORS
calculates the assigned factors for each cell type based upon the slope domain.
The performance of each cell type is re-adjusted based upon the cumulative proximity factor. sorts slopes and then randomly
Distribution phase
Groves
Buildings Agriculture
Land-Use Pattern
Based upon weighted factor the cell types are further segregated into different sub functions
Production estimation phase
Tree Type
Tree Maturity rate
Yield/hectare
De-logging rate
Crop type
Pastures
Yield/hectare
Animals/hectare
Population Density
Factor of Safety
Resource Consumption Rate
Hybrid Poplar: 20 tonnes/hec/yr
Juniper: 8 tonnes/hec/yr
Willow: 3-6 tonnes/hec/yr
WOOD PRODUCTION ESTIMATE
Wheat: 3 tonnes/hec/yr
Corn: 6 tonnes/hec/yr
Potatoes: 20 tonnes/hec/yr
Lemon: 30 tonnes/hec/yr
Leh Berry: 35 tonnes/hec/yr
20 sheep/hectare (of Pasture)
1 hectare of pasture can support upto 20 ewes with lambs
Evaluation phase
Performance Index
4- people /unit.
1 person consumes 1.5 kg of food/day 1 family consumes 1kg of wood /day
FOOD PRODUCTION ESTIMATE FITNESS
EVALUATION LOOP
BUILDING SAFETY FACTOR
BUILDING SAFETY FACTOR
SOLAR ACCESS
(Source: Author)
05-21
G.A RESULTS
Generating emergent land use patterns from genetic algorithm experimentation to achieve viable population thresholds.
OBJECTIVE
05-21.1 05-21.2 05-21.3
To distribute various functions/programs (building, agriculture areas and groves) on site, while maximising resource production and population count. Also, optimise for building safety factor and solar access and minimising soil loss during the process.
The system logic (Refer Page 144-145), depicts the multi-stage algorithm, that performs stochastic calculations based upon the weighted distribution of functions across the site. Soil loss and solar access are calculated again through R.U.S.L.E map as variable ground cover affects soil loss within the cell. Since the proximities of catchments(water sources) or Debris cells affects crop and grove growth rates, affecting resource production accordingly. A cumulative performance index is generated on the basis of the weight that is used as additional criteria for selecting the final Landuse pattern.
The graph above (Refer Fig 05-43), multiple population scenarios, where a clear divergence is seen after 50,000 (population) Indicating that during no given permutations between all functions is a population beyond 50,000 people possible. Although according to the performance index the Gen144.08 ( Refer Fig 05.42) provides the most stable relationship between resource generation and population count, along with a higher rating of solar access and a factor of safety. The following pages shows the best performing individuals from the experiment.
Previous Page: Fig| 05.42 Fittest individual from the land use GA which optimises population density with resource production.
(Source: Author)
Current Page: Fig| 05.43
CELL BREAKDOWN STRATEGY
Stratification of the fittest individual into different layers showing quantified data sets to sustain a specific population domain.
Cell Count:
Current Page (right): Fig| 05.44 Two mountain roads leading to the same valleys in Leh-Ladakh.
Integrating Primary and secondary routes to form cluster relationships along with proliferation goals for social infrastructure across the test patch.
The objective was to integrate primary and secondary networks that could be used as freight routes; serving the settlement, while connecting to the two largest villages in the vicinity.
The idea was to find nodes among the building clusters on the basis of 500 m radius distance in any direction. Once located, a weighted distance graph was generated, where shortest routes to the two largest villages were formulated inside the algorithm, using least gradient paths algorithms. Where we were trying to maximise the number of nodes and decrease the travel time, through reducing the depth within node connections. Also collision control against gabions and high-velocity flow lines were avoided; in an attempt to prevent land-slides over these constructed paths. Secondary connections were developed between the two paths connecting across the two valleys at every 300 m interval. These paths were considered as local connectors, since these regions are mostly traversed on either foot or on Yak's back by the locals, thus a higher gradient domain was used; resulting in shorter routes between valleys.
Social and institutional spaces were distributed in naturally existing flattest cells, along the primary network, also commercial activity was distributed along the intersections of primary and secondary paths and the size of these commercial spaces was controlled by their level of integration.
SABO VILLAGE
LEH VILLAGE
GROWTH STRATEGY
A ten year scheme showing different stages of land transformation leading to the emergence of a new autonomous settlement.
After initial mass movements, the debris spread can be excavated and cleared to construct the first level of retention structures, to prepare for forthcoming events.
(Refer to the sequencing strategy on page )
Due to annual debris flow events (as recorded from RAMMS analysis and risk mapping), the initial retention structures lead to the emergence of debris fields, that are the primary material sites for building construction. At this stage, local afforestation of hybrid poplars commences to stabilise steeper slopes.
By the end of five years, material harvesting in the form of timber and debris can commence to lay the foundations of a new settlement. This is the peak of activity scale where multiple activities can be conducted simultaneously. The initial wall and catchment setup, after six years provides adequate resources to sustain the work process.
Land Use Strategy
Along with debris sorting and poplar thinning, agricultural cells can be identified and set up, by utilising the soft terrain and available water sources. Crop sowing can commence along with pastoral growth to further reduce soil erosion and maintain coherence in activity.
(Refer to Land use strategy)
Retention Strategy 3rd
The onset of summer in the third year allows for maximum hydrological flow from glacial melts to be discharged into the valleys. The periodic construction of walls cause a significant reduction of talus formations thereby creating open fertile plains to maximise agricultural activity.
Retention Strategy
Once the debris has been sorted and timber stock piling is organised, the material can be transported to potential building cells which are in close proximity to all these factors.
Simultaneously, the expansion of agriculture, forestry and pastoral growth can be beneficial in rapid expansion of the settlement.
Once the drain patterns have been observed and recorded by the locals, the employment of conservation ponds can commence. As the cell locations for these ponds are pre determined based on cell convexity and flow accumulation, construction process is relatively faster due to reduced flow in winters.
(Refer to the catchment location strategy )
The retention structures continually provide material for building the side walls of the ponds. Further more, the scattered tributaries can be channelised by deploying earth-bag dikes as primary deflectors to maximise water volumes in the summer.
(Refer to hydrological efficiency experiments )
(summer) 7th year (autumn) 5th year (summer)
In this stage, the first signs of stable landscape emerge, where the hybrid poplars (sown in the 2nd year) start to mature. The expansion of walls for recurring material supply, water collection in the catchments and established stable slopes, show ample indications for population inhabitation.
Hydrological Strategy Land Use Strategy
8th year (winter)
In this stage, the building cells can be identified and foundation work can commence instantly. As winters are harsh for manual construction, this work is initiated in summer. The post autumn phase of the previous year is utilised in planting short term winter crops on expanded agricultural fields and balancing forest growth to compensate for previous resoure depletion.
Since earthbag assembly is a rapid and manual process, the structures can be quickly assembled to form primary living units. Also the seasonal agricultural produce can be harvested and stored in granaries of the nearest settlement. Continual expansion of slope stabilisation can now occur as a secondary process with the primary focus being on unit construction.
By the end of eight years, the emergence of different clusters in close proximity to all factors can be hypothised where the scale of activities is now distributed based on occupation and seasonal changes. All initial activities performing independently can now be integrated to form a unified community that can consciously plan for future self sustenance.
Building Strategy
CONCLUSIONS
Evaluation of various toolsets such as, debris collection, hydrological productivity,
INTEGRATED LOGIC
05-25.1
Development of three integrated toolsets as (1) Debris harvesting structures,(2) Hydrological harvesting model, (3) Land-Use model and (4) Network logic were successful in creating a feedback loop. As these models are only graphs of what the site offers, these systems have the potential to be integrated within, new or existing settlements. Although it must me noted that the the system proposes land patterns based on complete material and resource logistics, the dependency parameters can be altered to attain less dependent (resource driven) models as per requirement. In the case of the test patch(Leh) , a medium to low-density population is suggested, but do not take into account the related technologies and their limitations
DEBRIS COLLECTION
05-25.2
In the Debris mitigation and collection model, many assumptions are made regarding soil texture and maximum release volume (based upon 2010 flood results). Although, this model is well integrated with site soil and run-off parameters but does not consider the effects of snow avalanche scenarios. The retention structure models indicate an 83% collection of the total volume lost in 10 years of soil. Where a total material gathering (including material required to build walls) is quantized to 119568 (m3), this material can be segregated in accordance with the various size of sediments inside and utilised for reverse slope stabilisation or constructing dwelling units. This became a viable way to establish population limit based upon resource consumption.
HYDROLOGICAL PRODUCTIVITY
05-25.3
The Hydrological model was constructed using many assumptions about run-off variables and catchment efficiencies, which were extracted out of minimal resistance paths algorithms. The flow rate of glacial melt was recorded during the site visit and then interpolated for winter months, the s data was fed into the run-off model. Although, the constructed model does not regard any absorption and evaporation of water, but provides quick estimates for water resource extraction.
RESOURCE LOGISTICS
05-25.4
Tree sampling and crop production efficiency model provides estimates for soil loss control and resources such as food , grains and wood production. Also, ensures the balance between resource collection and production as opposed to consumption. While variation in production due to soil texture and proximities to catchments have been accounted for, seasonal and temperature variation are not.
LANDUSE PATTERN
05-25.5
A modified version of a genetic algorithm was constructed to derive at a fair exchange between various resource production strategies for different densities of population. Although, additional performance criterion's were imposed on the selection of the last individual. The pattern suggested an overall proliferation of functions for medium to low population density, which was further iterated into a 10-year growth pattern in accordance with a designed growth model.
CATEGORIES
OBJECTIVES
RESEARCH DEVELOPMENT
DESIGN DEVELOPMENT
BUILDING CLUSTERS
OVERVIEW
Development of building strategies based on generative landscape model.
The landscape strategies devised over a ten year growth model drives the material availability and potential of the building morphology in the design development. As most of the coarse debris would be v in assembling retention structures and earthbag dikes, the granular residual material serves as generative means of construction thereby reducing external procurement. Thus the inter-relationship of material usage through the decade proves crucial in deciding the population holding capacity of the settlement.
The primary logic of extracting building material from the debris is further translated into structures that would require minimal automation and would be flexible at various scales of design. The models are developed from initial studies of cryic architecture and are evaluated environmentally to generate autonomous clustering strategies that would be functional within a specific frame of design principles.
The segregation of debris into hard (gravel+rubble) and soft (silt + sand) resulted in an integrated assembly of earthbags and gabions that can effectively mitigate rapid residual flows based on the orientation and thickness of enclosure. The data acquired from analysis of earthbag construction is translated into definite rule sets for generating morphologies.
Current Page (right): Fig| 06.1 Utilization of debris collected to build gabion side walls. Seen on site at Leh-Ladakh (India). These retention structures are currently deployed to define linear paths for water collection and channelisation.
(Source: Author)
MATERIAL SYNTHESIS
Segregation of material resources aiming towards a rational design approach.
MATERIAL DRIVEN INITIAL STATE OPTIMIZATION
The extraction of blue clay from river basins and sandy loam from fertile valleys led to substantial depletion of the existing wetland around the rivers and incremental reduction in agricultural output. The lack of co-ordination between material management and resources created an indefinite demand of generating building material that would be imperative of land excavation activity. The abundance of debris characterized by rapid mass movement is seen as a potential of investigating an alternative source of building material that would contribute in reducing the logistical pressures of material challenges.
The limitation in frequency of material procurement due to complex terrain and unstable climatic conditions led to the investigation of a locally sourced material that can be utilised in creating a system that would require negligible automation and minimum reliability on foreign sources. Since the region is characterised by periodic debris flows, the accumulation and segregation possibilities of debris have been studied and recorded. The current practices of earth construction are explored to understand the potential and constraints of each system in relation with cost efficiency, material knowledge and assembly process.
Considering all due factors of lateral loads from debris flows and gravitational loads from self weight, the strategies for form generation are optimized based on material proximity, component dimensions and structural performance. The results provide possibilities of material packing within prescribed geometrical constraints.
Conglomerate Breccia
Current Page (above): Fig| 06.2
Diagrammatic representation of debris classification by grain size.
Note: Grain size > 256 mm are termed as boulders (not represented in diagram above)
Current Page (right) Fig| 06.3
An enlarged representation for grain sizes lower than granule. Sand and Silt are further classified into sub-categories like fine and coarse (not represented in diagram)
(Source: Author)
COBBLE
BOULDER
PEBBLE
GRANULE
SAND SILT
CLAY
GRAVEL
MUD
Siltstone/Shale
DEBRIS CLASSIFICATION
Investigating the properties of a debris [earth] as a naturally abundant resource for construction.
The disintegration of accumulated matter into respective components (as shown in fig. 6.4) and the structured recombination in differential percentages delineates the physical properties of the material. The primary advantage of exploring earth construction techniques apart from cost efficiency and abundance is thermal insulation which is an essential criteria in the site’s climatic context. The obstruction strategy proved beneficial in harnessing debris control in different parts of the test patch where material generation became emergent from the sequential annual phasing experiment.
An on-site soil sampling was done as a part of field survey to segregate the soil texture into organic, active and inert. While the organic content is most likely to be utilised in maximising agricultural practices, the active and inert properties contribute in generating building material that suggest a series of options in localised construction. This idea was further investigated as an effective strategy to gain complete control over the settlement growth patterns that would emerge in and around the material collection points.
EARTH
GRAVEL
DRY/ SOLID
GABION
RUBBLE
HUMID
(Source for all: Author)
PLASTIC
MATERIAL UTILIZATION
SILT SAND CLAY
BAGGED BLOCK
RENDERING
Identifying the common possibilities of architectural construction, through combination of differential amounts of extracted material post debris segregation.
The structural strength of earth based system depends primarily on the granularity of the material and its proportion in the mix. Most of the construction techniques require limited machinic processes and can be managed under manual operations. However, in terms of infrastructural setup and material texture, gabions and bagged systems prove to be a more comprehensive approach as opposed to block production techniques. The abundance of dry material in the region with finite moisture content and plasticity provides limited potential of devising an assembly system that can be rapid and emergent in subsequent years.
The potential of valuable granular material is harnessed through agriculture and vegetation growth strategy as maximum hydrological flow lines traject silt and sand to the valleys. This in turn reduces the availability of soft material as the retention structures accumulate maximum dry gravel and rubble from the debris. The weathering and sliding of hillside debris flows typically start as a sliding detachment of material (upland debris slide, peat slide, rock slide etc.), and usually breaks down into a disaggregated mass that is coarse in texture, but granular in volume. On studying the various structural possibilities, it is observed that mass production of earth blocks requires adequate time for curing which is extremely unreliable owing to the site’s constant micro-climatic variation.
Previous Page: Fig| 06.4
06-2.3
SOFT EARTH FABRICATION PROCESSES
An analytical understanding of earth fabrication techniques as a resource based medium of construction and sustainance.
DUG OUT (EXCAVATION)
MORPHOLOGICAL CONSTRAINTS: vertical access, uni-directional light and ventilation
+ increased thermal mass and energy efficiency
- robust waterproofing required
CUT BLOCKS (MODULAR)
MORPHOLOGICAL CONSTRAINTS: height limitation due to stacking, vertical assembly
+ fast and economical - intensive labour and specific soil required
- labour intensive, prolonged curing & setting period
WATTLE & DAUB (LATTICE)
MORPHOLOGICAL CONSTRAINTS load bearing structures only
+ panelization; long spans; high thermal mass - slow process, limited openings
FORMED (BONDING)
MORPHOLOGICAL CONSTRAINTS: light weight walls, permanent skeletal support
+ flexibility of pre-fabrication - high clay content (binder) required
INFERENCE
A conclusion based on analytical study of earth construction system.
COMPARATIVE ANALYSIS
Earth construction offers a variety of options that can be combined into a hybrid system to adapt to the surroundings it is embedded in. However in terms of morphological constraints and time period, each technique provides variable results. A comparative assessment of different soft earth fabrication techniques (as shown in fig 06.6 to 06.14) provides the basis for deriving the most effective assembly process that fits within the frame of the context to generate morphologies that can be quick to construct, repair and rebuild with minimal automation and material knowledge.
RESOURCE BASED
For lack of aggregate material in both availability and ease, along with skilled labor for construction, earthbag stacking is seen as a potential system to aggregate structures with relative ease. However, earthbag structures have not typically been engineered, but rather are designed using rules-of-thumb developed through trial and error(Pelly, 2009) thus, demanding research into material properties specific to an ecological model. Earthbag structures usually consist of polypropylene bags stacked in a corbeled fashion to create a catenary dome, with layers of barbwire between courses to provide shear resistance (Vadgama, 2010) depicting high compressive strength with a high load capacity. However, earthbag structures often come in curved forms (such as domes) and a worthwhile investigation would be one that compares architectural form alongside strength. Curved wall forms entail different strength characteristics under lateral loading, not only because of effects such as hoop stress, but also due to geometrical differences for elements such as the render. Vernacular earthern architecture often adopts forms that perform well in compression since earthbags perform badly in tension this approach should be adhered to, if efficient earthbag structures are to be designed.
TOPOLOGICAL FLEXIBILITY
Extensive research has been conducted on earth-bag construction, especially during the last decade providing good analytical models of their mechanics under vertical and lateral loads. However, no precedence of morphology optimization is seen. This research further attempts to utilize this knowledge and exemplify an integrated construction system based on material proximity as the primary driver of assembly.
A review of the current practice and morphological variation in earth bag architecture.
DOME
DIMENSIONS:
maximum diameter: 6096 mm (height = diameter)
STABILITY:
1) self supporting structure
2) strong under stresses
CONSTRAINTS:
1) connecting multiple domes
2) limited volumetric space
DURATION: [months]
COST: [GBP/sq.ft.]
VAULT
DIMENSIONS:
maximum span: 2438.4 mm
(height = 10 * wall width at base)
STABILITY:
1) highly stable due to metal quonsets
2) facilitates multiple connections
CONSTRAINTS:
1) complicated assembly
2) increased cost of permanent formwork
DURATION: [months]
COST: [GBP/sq.ft. + quonsets]
CUBOID
DIMENSIONS:
length = buttress spacing (3048 mm c/c) (height = 10 * wall width at base)
STABILITY:
1) depends on buttress/ internal walls
2) increased stability in curved walling
CONSTRAINTS: 1) vertical instability due to leaning
independent roofing assembly required
DURATION: [months]
COST: [GBP/sq.ft. + buttressing]
Current Page:
Fig| 06.15
Earthbag domes in Venezuela. Built by alumni Alejandro Lopzy who now teaches and builds throughout Costa Rica through his organization GeoBunker.
Fig| 06.16
Junoot, Oman Collaboration between CalEarth (led by alumni Hooman Fazly), URC, and SSH. Awarded the World Architecture Award in 2012.
Fig| 06.17
Casa Antakarana built in Colombia. Designed by architect Jose Andres Vallejo who trained at a Cal-Earth workshop at Organizmo in Colombia.
(Source: Author)
EFFECT OF STACKING
Difference in curvatures through variable height to span ratios.
(Source: Redrawn from
SPAN TO RISE
Earthbag is a non-homogeneous mixture of soil filled inside a bag; these bags can either be hessian or polypropylene (anisotropic). A stabilized fill (earth) with fibers or cement inside the bag improves cohesion, increasing bending stiffness of the system. To further, increase the performance, these bags are compressed (using heavy weights); providing a block like structure to the bag. These blocks are then stacked in courses (like bricks)and tied together using tension wires, to prevent shear failure.
The combined effect of the fill and the bag, have a complex behavior when subjected to stresses. The basic parameters of earthbag construction are explored here through practical means by using the Mohr-Coulomb law. (Vadgama,2010)originally proposed this method during his literary works.
Mohr’s circle-stabilized
Mohr’s circle-unstabilized
Earth is a cheap material found in abundance, that doesn’t require much skill to construct (Stouter,2011). Most importantly, the material allows for high deformation, avoids collapsing under stresses. From the precedences (As shown in fig. 06.8) it can also be inferred that both applying barbwire and rendering between courses causes significant improvement in strength. Cement stabilization increases the flexural strength & shear strength by a factor of 7 (Vadgama,2010). Stack height to width ratio(h/w>=3) for end restraints to be neutralized (higher stiffness).
Current Page (right): Fig| 06.18 Diagram explaining differential height to span ratios under the effect of stacking. The limitation in corbelling to get a definite curvature is highlighted here.
Current Page (below): Fig| 06.19 Mohr’s diagram showing the difference in failure lines under the influence of cement stabilization.
Vadgama, 2010)
06-2.7
SYSTEM PERFORMANCE
Testing bag dimensions under different load values as derived from RAMMS analysis to identify material usage per bag.
Current Page (right): Fig| 06.20 Diagram explaining deflection in shape for flexural wall, with single [left] and twin[right] applied loads.
(Source: Redrawn from Croft, 2011)
Current Page (below): Fig| 06.21 Mathematical method of calculating forces acting on one earth bag
(Source: Redrawn from Vadgama, 2010)
Moment diagram overlaid onto vertical stress distribution.
Moment diagram overlaid onto normal stress distribution.
Once the bending moment, reaches the normal stress at this point, bending failure occurs.
MATERIAL ECONOMY
06-2.6.1
Bending stress must exceed the normal stress further down with twin loads.
H= Initial height of the bag, H0= Final height of the bag
B- intial length of the bag, B0= Final length of the bag
v = Vertical stress exterted by the bag on the soil
h = Horizontal stress exerted by the bag on the soil
The initial RAMMS analysis provided data sets consisting of variable debris pressures. This domain of debris force and the maximum pressure induced was used as an input value for structural load testing of variable bag dimensions. Apart from the height to width ratio, the compactness of the material fill also determines the compressive strength of the bag against in plane forces.
For the sake of calculating the amount of material required per unit, a standard bag size is assumed for the entire proposal. This size is confirmed from structural experiments for the least displacement under maximum loading conditions (as shown in fig: 06.22). The displacement in other prescribed bag sizes is nearly uniform compared to the selected bag size.
The understanding of material requirement and usage to develop locally constructed inhabitable spaces proved critical in determining the maximum viable population and program distribution within the test patch.
It was also noticed, that earthbag structures are most likely to overturn and fail in impact resistance in high-pressure areas thus suggesting that gabion retention structures would prove to be a more effective strategy. However, earthbag structures would perform significantly well in deflecting low pressure residual mass flows.
SETTLEMENT STUDY
INDIGNEOUS TISSUE SAMPLE
Old Town of Leh
RESOURCE MANAGEMENT
Enclosure Value [EV] Open Space Ratio [OSR]
Orientation
Solar Radiation Visibility Index Shade & Shadow
Year 1 to 10
SPATIAL QUALITY
POPULATION DENSITY
UNIT LEVEL
CLUSTER LEVEL
06-3
CONTEXT STUDY
To identify relevant parameters for a comprehensive design approach.
SETTLEMENT STUDY
06-3.1
It is important to note that most of the traditional mountain settlements have evolved out of knowledge passed on by generations and experience gained through anthropogenic activities. In order to gather a clear understanding of the functionality of spatial interaction at unit and cluster level, an indigneous settlement study is conducted.
The historic settlement of Leh dating back to nearly 17th century was studied as a part of the field survey. Different clusters from a sample tissue are identified to extract spatial and organisational logics that can be converted into numeric parameters as design inputs.
CLUSTER ANALYSIS
06-3.2
Since the development of the settlement relies maximum on the topography, the village has evolved in fragmented isolation. However, due to historic and religious significance, a recently developed high density patch has been selected to establish an understanding of the architectural characteristic of the region.
The analysis is divided into four broad categories that take into account the different factors that accentuate the spatial quality of the settlement. As Leh is majorly autonomous in space planning, the orientation of singular units and distribution of open spaces plays a significant role in the formation of building clusters. Environmental changes have a direct impact on the architecture of the region, and determine the spatial characteristics and usage of each building.
STUDY PATCH Area:
12.85km
19.19km
OLD TOWN OF LEH (LADAKH)
BACKGROUND
A brief overview of Ladakh, with specific focus on the historic ton of Leh
CONTEXT
The district of Leh is the largest district in India, with a total ground coverage of 45,110 km2. It is the capital of the Tibetan kingdom of Ladakh and is at the brink of unpremeditated imbalance of urbanization. Leh is embedded in the Indian side of the Tibetan Plateau at an altitude of 3500 meters above sea level. The remoteness of this region gives precedence to connectivity and reliance on natural resources as the primary sources of maintaining health and survival.
DEVELOPMENT LOGISTICAL ISSUES
The village was initially discovered as a caravan link to establish trading connections with China and Pakistan. It was also a transit point for traders on the Silk Route. In the early 1900’s, almost all the villages of Ladakh incorporated agriculture and livestock husbandry as primary drivers of economy and thereby contained the traditional heritage for survival. In mid 1970’s, Leh was exploited as a potential site for mass tourism as opposed to its initial incessant existence. The rise in infiltration of tourists, both local and foreign has created employment opportunities to the native population leading to deflation of the original source of economy. The need to sustain land based economy in relation with the current occupational tangency is vital as Leh-Ladakh has started to rely heavily on critical commodities like food and water supply to support tourist activity. This reliance in addition to material procurement adds to the suspension and inadequacy.
The paucity of government initiatives to stabilize the import-export system has laid the foundations of privatization in all sectors of economic dominance and commercialisation. This is further reinforced by the Leh Airport and the National Highway which are the only modes of transport in a 250 mile radius. Due to recurring ecological changes, the architecture of this region is autonomous and solitary to the context it is based in. The planning of units to clusters to settlement growth patterns takes into consideration the structural performance of the system and attempts to minimize infrastructural losses. However, the current growth of demography and commercialization in the region lay tremendous pressure on the indigenous techniques of construction.
06-3.2
SETTLEMENT STUDY
An understanding of the current spatial hierarchy in nearest existing settlement (Leh)
Current Page (right): Fig| 06.25
The following images show the amalgamation of vernacular and contemporary architecture in Leh. Urban Pressure and infrstructural demands have increased the growth of the settlement on steeper terrains, making it prone to structural failure.
(Source: Author)
Next Page (right) Fig| 06.26
The following maps have been generated from data collected from field survey and previous statistics. These maps give an overall outline of the architectural character of the settlement.
(Source: Author)
06-3.2.1
DENSITY DISTRIBUTION IMPORTANCE
06-3.2.2
It is important to realise that the indigneous high altitude mountain settlements have evolved from experience and traditional building knowledge passed down by generations. The settlement study is done to capitalise on previous studies and data sampling done on the site to gain relevant inputs that can be utilised as governing base parameters.
The density of Leh is distributed in two categories, the scattered type around agricultural fields on flatter slopes and closely packed clusters concentrated around temples and monasteries on steeper slopes. The stagnancy in construction development has led to a uniform logic of assembly over the entire terrain. This causes heavy maintenance issues and frequent building failure. It thus became necessary to understand the root cause of various malfunctions in order to establish a better understanding of the existing morphological setup.
MATERIAL ACCOUNTABILITY
06-3.2.3
It is extremely essential to note that the selection and development of material system in Leh relies largely on the manual capability of handling and assembling with negligible automation. Thus, earth and stone are exploited to its absolute potential in laying foundations and enhancing the structural performance of the building. Timber and Glass are secondary elements that support the aesthetics and decentralize long spans to transfer loads uniformly. The cumulation of materials is done prior to the construction in adherence with the seasonal variation as the texture of soil and quality of timber can differ drastically.
Current Page (below): Fig| 06.24
An artist’s representation of typical vernacular architecture, the Munshi House before restoration.
(Source: Redrawn from LAMO Archives_ladakh arts and media organisation: Restoration of Munshi House)
c
BUILT FORM
Most of the buildings in Leh are closely packed due to minimum contour intervals. The interdependency of units both spatially and structurally has enabled height restrictions and internally connected shared spaces. Thus there is no distinct morphological variation in the settlement.
BUILDING USE OPEN SPACE
As the settlement has evolved on an uneven terrain, widespread flat patches of land are extremely uncommon. Most of the available flat land has been utilised to construct large scale educational and religious type buildings. Thus the open space distribution is in the form of vacant plots emerging from the incremental architectural pattern and and internal courtyards within individual dwellings.
The interconnectivity of interior spaces has created a series of mixed use program distribution in the settlement with the dominant pattern being, single family units converted to lower floor restaurants and guest houses. The incremental shift from agriculture to commercial tourism is evident from this study.
It is observed that most of the buildings are aligned along the East-West axis to maximise south facing surface area for maximum solar access. However, the similarity in building heights and shared walls restricts the surface exposure to a great extent leading to cold internal spaces in winters.
Multi Level Courtyards
Stables/Sheds/Larder
Private Spaces
06-3.3 UNIT LEVEL ANALYSIS
An investigation of interior spatial complexity of traditional units in Leh.
PROGRAM DISTRIBUTION
06-3.3.1
The distribution of spaces in a traditional unit is highly symbolic and their vertical or horizontal connection depends on the dimension and positioning of the rooms. The fire place, toilet and guest rooms are all on the first level, connected horizontally to each other by a linear passage. The vertical connection varies at different levels, connecting the lower floors by a singular staircase and upper floors by a ladder. The entrance of the house is generally on a higher plinth that allows the basement to function independently.
ORIENTATION
06-3.3.2
PLAN SCHEME
06-3.3.3
Apart from astrological and religious considerations, the orientation of the building corresponds to environmental benefits. The south facade is usually provided with larger openings to harness direct light and solar radiation. The north facade is more of a defense barrier to avoid heat dispersion through cold winds. The direction of wind flow determines the orientation of the rooms and they are generally towards the south west to maintain cooler temperatures in summer. However, the general orientation depends on the altitude and summer temperatures due to their incremental variation over short distances.
The morphology of the natively built form in Leh pertains to the topography and soil texture that encompasses it. The irregularity in form and space is common to the traditional planning scheme of the structure. However,the primary objective amongst the locals is to ensure flexibility of the spaces within to reconfigure and support multiple functions depending on the seasonal or economic changes.
Current Page (above): Fig| 06.28 Cut-away drawing of a typical Ladakhi balcony construction indicating timber joinery and visual ornamentation.
(Source: Redrawn from LAMO Archives_ladakh arts and media organisation: Restoration of Munshi House)
Next Page (right): Fig| 06.29 Unit level plans and sections categorised on topographic gradients
Current Page (right): Fig| 06.27 Section illustrating distribution of internal spaces on different levels highlighting spatial complexity.
(Source: Redrawn from LAMO Archives_ladakh arts and media organisation: Restoration of Munshi House)
It is a common observation that the vertical connection of internal spaces in native Ladakhi dwellings increases with increase in topography gradient. This leads to the emergence of various split level terraces and independent spaces that can be assigned to support various activities. This is the primary reason for conversion of previous dwellings into residential schools, guesthouses and market spaces.
The analysis of current trends of family patterns and area per person for different unit types is illustrated above. This proves beneficial in generating relative open versus built values that may or may not be modified in future experimentation.
06-3.4 CONSTRUCTION LIMITATIONS
Assessment of existing construction techniques with specific focus on critical architectural elements.
Current Page (right): Fig| 06.29
A local mason (Kamali Phunsukh) explaining the problems of traditional construction in today’s scenario.
“There are seven different types of material procurement that need to be done prior to any construction.”
(Source: Author)
Next Page: Fig| 06.30 to 06.32
Detailed drawings of critical elements unique to Ladakhi style of construction.
(Source: Redrawn from unpublished thesis_A Fading Legacy: Ladakh’s Vernacular Architecture- Edoardo Paolo Ferrari )
UNIT SEGREGATION
06-3.4.1
The architecture of Leh can be divided into two broad categories based on the presence of foundation. Houses without foundations are constructed on rocky hillsides and require an adaptive basement to rise from an irregular surface. The primary reason for constructing such blocks was the scarcity of excavation tools and knowledge on rock leveling techniques. The basement, built from rocks of smaller dimension are used to level the ground for further extrusion.
DIMENSIONING
06-3.4.2
SEASONALITY
06-3.4.3
The clear dimensions of spaces depends on the material storage and occupancy within the unit. The rooms are generally small as opposed to the main fireplace room which is utilized for social activities. Material scalability; buckling of poplar rafters for longer spans restricts the internal dimensions of the building. Low floor heights (2100 to 2450 mm) maintains thermal comfort and minimizes heat dispersion. The openings are positioned very close to the floor since all activities occur on the ground and require adequate light and ventilation through the day.
Seasonal variation is crucial in determining the duration and cost of construction. Initially construction was more individualistic and visceral in collaboration with skilled masons. Recently, rapid construction using modern materials and external labour has proved detrimental to the building performance as it entirely negates the knowledge and ecology of the region. The next page illustrates some critical aspects of Ladakhi architectural style which can inform the effective utilisation of “generated on site” material.
FOUNDATIONS
06-3.4.3a
06-3.4.3b
The foundation is usually laid over the ruins of an existing house. (Pommare-Imaeda 1980, p. 249) Depending on the slope aspect and soil quality, the height of the foundation can vary from a plinth of 300-450 mm to an entire ground floor. The sole criterion for the foundation work is to achieve a flat base on a sloping terrace to facilitate wall erection. Thus, the plinth on flat land is lower as compared to construction on steep ground. (Interview: Tundup Namgyal Manepa) It is only when foundations are built on sloped terrain that the lower floor is constituted of wooden joints spanned on foundation walls. (Khosla 1979, p.116) The plinth is usually wider than the external walls to enhance the structural stability through minimum buckling.
The typical foundation work is executed by determining the depth of the trench based on soil division. The earth is compressed several times to compact the soil and prevent water percolation, before the structural pillars or stone masonry is eventually laid out.
Walls in high altitude construction serve two main purposes; structural support and insulation. The load bearing walls are usually made of stone, sun dried bricks, rammed earth or stud walls with timber framing. Stone construction, being the most primitive one does not require any mortar or additive dressing. However, resolving corners in stone masonry construction is tedious, hence brick masonry is preferred. Brick construction from manufacturing to drying and placing requires specialized skill and application. The insulation is much lesser due to thinner sections, so most of the locals resolve to using rammed earth construction. Also the type of brick bonds used are native and require experiential skill for execution.
Rammed earth construction requires a durable framework for casting the earth. However, while the earth is being rammed, the willow framework tends to expand because of reduction in its tensile strength leading to a swollen wall section. But in comparison to stone and brick, rammed earth walls serve as a more competitive and efficacious solution.
06-3.4.3c
The openings are mainly located on the south and east facade of the unit to harness adequate light and ventilation. There is no quantified relationship between the room size and aperture dimension. The openings are lower in dimensions, cill and lintel levels as compared to a conventional window primarily for two reasons; to avoid heat loss towards external and internal rooms, sporadic availability of glass and refrain from using large timber sections. The clear dimensions of external openings increase significantly from the lower floors to the upper floor. This reduces the weight of civil construction on the upper floor mainly due to the use of timber elements. The floors above provide a greater visibility index both internally and externally, thereby being decorated by wood carving techniques. These are elaborate woodwork integrated with the wall construction.
Apart from windows, the anthropometry of doors is also an important feature. External doors are usually 1220 -1500 mm in height as opposed to internals; 600-900 mm. The assembly logic is similar to that of the window, excluding the ornamentation.
Wooden Ties Timber Beams Half Lap Joint
Rubble Masonry
06-3.5 CLUSTER LEVEL ANALYSIS
Comparative analysis of occupation based clusters to generate relevant design inputs.
Current Page (right): Fig| 06.33
A map of the Old town of Leh showing different clusters that are compared and analysed. The selection of clusters was done on the type of maximum space utilisation within each cluster.
(Source: Author)
Current Page (right): Fig| 06.34
Comparative analysis of different clusters on environmental and social parameters.
(Source: Author)
PROGRAMMATIC DISTRIBUTION
06-3.5.1
The distribution of social and cultural activites in high altitude regions is never too distinct. However, it is observed that the terrain primarily drives the building typology based on subsequent contour intervals and walkability. Markets and educational types are most likely located on flatter slopes whereas individual housing units emerge on sloping terrains. The built fabric between the two is a transition from public to private thus giving rise to mixed use typologies.
Based on this understanding, the settlement is analysed in the form of eight different clusters that share similar function but show signs of slight variation in space planning and orientation.
INFERENCE The closely packed clusters account for limited open spaces and visibility. The mutual shading further creates internal dark spaces which become redundant in winters. However, the radiation analysis suggests possible means of harnessing solar energy which, is already being realised and implemented in most of the dwellings.
The comparative analysis forms a translational set of numerical data to organise the proposed building clusters in a way that can improve the existing data findings. To design on a terrain unknown and undocumented, it becomes vital to consider crucial aspects unique to the indigenous architecture of the region. The combination of statistical information and computational analysis provided qualitative data that can be consciously utilised in generating morphologies within the prescribed material constraints.
Enclosure Value (EV)
06-4
INTEGRATED DESIGN
Summary of conducted study of material and settlement patterns discussing possibility of integration to form a material driven designed system.
MATERIAL STUDY
06-4.1
The material study suggested possible means of utilising the complete potential of the debris extracted into generating units that can be flexible and functional. Since debris collection and timber procurement is a recurring process, it can be effective in dictating the maximum viable population that can be sustained in the region, thereby controlling resource logistics of import and export.
Most of the studied techniques of earth construction require prior setup or a specific environment where the assembled structure can be less prone to building failure. Since plastic wasting is also one of the current potential problems on the site, the same material can be recycled to rapidly produce debris infill polypropylene bags at a component scale to further drive the construction process that can be highly adaptive to the current scenario.
SETTLEMENT STUDY
06-4.2
The indigenous settlement study provided us with qualitative data of spatial organisation and social activity patterns that could be interpolated as numerical parameters for algorithmic computation. The notion of a new architectural intervention that can be sensitive to the context it is embedded in and can be suited to local needs can formulate base rules of material synthesis and population control mechanisms.
The analysis at both unit and cluster levels suggested various possibilities of simplifying the spatial complexity that exists due to terrain dominance. Strategies devised in the research development chapter and requisite mapping of the entire context proved of prime relevance to consciously design and generate autonomous building units that be aggregated to a variety of possible combinations, depending on the functional requirement on site.
DESIGN PROPOSAL
Experiment Sequencing
Morphological Segregation
System Logic
Density Distribution Inferences
Aggregation Possibilities
MATERIAL STUDY
Based upon Land use patterns From previous chapter
CATEGORIES
UNITS CLUSTERING STRATEGY SHAPE GRAMMAR
Based upon material research Flow dynamics
OBJECTIVES
To adhere to social requirements
Maintain structural integrity
Self shading as ecological parameter
NEIGHBORHOODS
Based upon settlement research Seasonal patterns Spatial & Social patterns
Re-direct remaining debris flow
Increase units interaction
Self shading as ecological parameter
High build-ability & safety factor
Structural Performance Flow dynamics TEST PATCH BREAKDOWN
MORPHOLOGY GRAMMAR
DESIGN & OPTIMIZATION STRATEGY
EVALUATION STRATEGY
Based upon Networks Escape-route strategies
Maximum Heat gain during winters
Grow & Store Food
Grow & Collect Wood
Groves
Agriculture
Catchment surfaces
Agriculture clusters
Water Catchments
Intercropping
Material sites
Material clusters
Previous Page: Fig| 07.01 Diagram depicting work flow for the entire chapter.
(Source: Author)
Current Page (right): Fig| 07.02 Top view of the extracted test patch (Source: Author)
Current Page (bottom): Fig| 07.03 Diagram of test site, from which the patch is extracted.
(Source: Author)
07-1
EXPERIMENT SEQUENCING
Combining previously generated logics to devise a comprehensive strategy for building morphology.
DESIGN AMBITION STRATEGY
This section explores viable solutions to integrate density distribution strategies inside the previously developed land-use model. The patterns was optimised to mitigate residual flow during flood events considering ecological parameters. At unit level, the designed model is embedded with social parameters , which were modified for possible integration within the pre designed landscape.
The data extracted during Chapter four, (risk and debris flow analysis) were used for density distribution, while data sets from settlement and material study expedites morphology design. The settlement pattern were designed keeping in mind the flooding scenario, where residual flow from the walls seeps through into the habitable spaces(building cells). The idea was to develop a mitigation strategy using morphological variation, where the morphologies themselves act as dynamic barriers ; safeguarding the sensitive areas.
A test patch of area (0.8 km2) was considered as the base over which a genetic algorithm was developed. Where we attempted at achieving maximum residual flow mitigation (through recursive fluid diversion calculations) and direct solar gains, while minimising self shading between units. The algorithm was integrated with a modified version of C.F.D (computational fluid dynamics), which helped predict flow directions after diversion from morphologies. This resulted in a differential scale risk map at a cluster level, where public and social function were placed in low risk zones accordingly. After due experimentation, this section concludes with a diagrammatic representation of the integrated proposal as new means of re-inhabiting the cold desert biomes with the aim of balancing resource management with the inevitable population shift.
07-2
MORPHOLOGICAL SEGREGATION BY FUNCTION
Differentiation in morphological type based on material proximity and functionality.
After generating a comprehensive land use plan, the prominent material sites are identified. The distance between the debris collection sites and derived building cells (within a walk ability range of 500 to 800 m) forms the primary basis of setting up the permanent dwelling units. These distances are mapped using simple radius calculation.
The shortest walking distance from the previous stage leads to formation of the first level of emergent clusters that are set up on site. The density distribution experiment (explained further) determines the amount of material and duration required for the assembly of each cluster.
Since debris sorting and preparation of compact earth bags is a complete manual process, secondary activities like agriculture and afforestation can commence simultaneously. This distribution of work patterns ensures uniform growth of the settlement where both resource production and inhabitation complement each other.
The complete assembled unit is a load bearing permanent structure that can efficiently adapt to the terrain it is embedded in. Recurring material supply provides additional benefit of expanding one unit into linear autonomous clusters.
RESOURCE GENERATION
The recurring generation of material around retention walls and growth of forest groves accounts for the primary source of construction material. Since the position of groves and gabions walls have been optimised in the previous experiments, they are well within the proximity radius from the building cells.
The construction of multiple walls over a span of ten years is bound to have an impact over the terrain and create empty parcels of land. Thus, it is best to rapidly assemble light-weight temporary units in these vacant plots that can allow for initial population inhabitation, and also make effective use of the land available. These units can be expanded horizontally over a period of time, or else the plots can be converted to agricultural lands.
With the aim to utilising material to the maximum potential, the debris is assigned to the more permanent earthbag structures while, timber is harvested to build parasitic frameworks that can be supported by the existing retaining walls. This eliminates the process of debris sorting and speeds up the construction process.
This section explores viable solutions to integrate density distribution strategies inside the previously developed land use model. The patterns was optimised to mitigate residual flow during flood events considering ecological parameters. At unit level, the designed model.
07-3
SYSTEM LOGIC
Logic diagram explaining the process of clustering units towards an integrated proposal.
After locating the landscape elements on site, the potential building cells are identified. A flow model is generated based on previously quantified data to visualise all residual debris flow lines that intersect with the building cells.
The circles are evaluated on the basis of maximum inter connections between consecutive circles. The circles are ranked on the basis of centric distance between the units with the least distance being the fittest for the sole reason of structural stability. Units are coupled together based on average family size and area per person, which in this case is 9.0 m2 IDENTIFY BUILDING CELLS
A circle packing algorithm is created within the exterior boundaries of the building cells. The diameter of the circle pertains to the indigenous unit sizes as derived from the settlement study chapter. The criteria of packing the circles together is to maximise the ground coverage within the diametric domain and maximise visibility from all sides.
OPTIMISING POSITIONS
The positions of the circles are further optimised within the cell boundaries by a genetic algorithm based on three parameters; 1) mutual shading 2) flow line intersection and 3) a domain of slope degree. Units emerging on steep slopes are discarded/killed as they are prone to structural failure and periodic maintenance.
PERFORMANCE EVALUATION
SEGREGATION BY FUNCTION
Based on tangential intersection of flow lines, the performance of the units is evaluated and are ranked accordingly. The non-performing units are converted to light weight temporary units (type 02). Units that effectively deflect residual flows are proposed as type 01 units that are more permanent and durable.
The combination of landscape elements and proposed building type results in an integrated settlement model where each unit is functional in its own unique way. Type 01 units deflect residual flows while the temporary structures anchored to retaining walls contribute in channelising or containing debris flows.
Radiation and self shading
Previous Page (top) : Fig| 07.04
Diagram depicting the interaction of flow lines with built configurations. (Source: Author).
Previous Page (below) Fig| 07.05
Diagram depicting the built form with radiation analysis and self shading shadow patterns. (Source: Author)
DENSITY DISTRIBUTION
To explore various density distribution patterns, that allows for requisite amounts of resource and food generations to sustain itself.
AMBITION
The premise of this experiment is to understand the viable densities possible, by pairing different residential and agricultural morphologies together, while maintaining clear drainage paths for mass flow dissipation.
MORPHOLOGIES
The designed units can house anywhere between 2-12 people. These units when scaled, houses varied functional requirements allowing for a modular construction system, which is developed for mass production. The dwelling units absorb and divert mass flows where larger morphologies allow for greater redundancy in space usage, facilitating not only commercial and residential use but also mitigating periodic mass flow.
PARAMETERS
EVALUATION
The design proposal relies on the flow-line drain model created through RAMMS in the previous chapter to estimate the relative direction of flow along the terrain. The units divert residual flow through the forest or inter-cropping areas towards the nearest debris or water catchment. Thus avoiding significant flow to interact with agricultural fields. The functional aspect of the dwellings (i.e., is directing or containment) decides the type of morphology and its position in the overall context. Other technical buildings such as greenhouses, educational blocks and markets are set in the larger safe zones, since these morphologies cannot resist high-intensity mass flows. The temporary nature of greenhouses provides extra redundancy allowing for this structure to prop up anywhere as per the annual food requirement. Stochastic calculations are based upon the following pattern: where a 400 m2 field yield a produce of 600 kg at a rate of 1.5 kg/m2/year. Since a greenhouse provides food all year around the total produce is 1000Kg at a rate of 2.5/m2/year. Considering that a person in the high plateau region consumes 365 kg /day (1kg /day) one greenhouse supports eight people considering 50% is supplied through greenhouses.
Multiple contradicting criterion’s are used to integrate settlement growth with environmental parameters. Besides the mass flow reduction, the selected path of 0.12 km2 is densified based upon self-shading, and other attributes passed down from the Land use plan. The mass flow algorithm tried to pack units together for higher resistance whereas the self-shading tries to space out the clusters. Also, the algorithm created accounts for the assumed group character based upon settlement research, allowing for various open spaces for each dwelling unit, this allows for a plausible exchange between different program distribution.
Since primary clusters are of the agricultural and residential type, the main objective is to decrease in solar gains due to self-shading both in dwellings and on agricultural lands. The design is differentiated through variable spans and heights to reduce self-shading while minimising the space between units to allow for higher resistance to the mass flow.
G-49.03
G-104.07
G-150.02
07-5
INFERENCES
Developing various density patterns and optimising it against residual flow, while minimising self shading between units.
SETUP
The setup combines computational fluid dynamics within the domain of recursive circle packing algorithm, where the clusters are generated and fused together based upon proximities and spatial requirements(per person). These emergent clusters are evaluated upon conflicting criterion’s, of increased population density and decreased self-shading. Also, the clusters were analysed for flow mitigation, in terms (%) of land safeguarded from residual debris movements. The flow direction and velocities were extracted from the previously generated dataset in Chapter four.
OBSERVATION
During the experiment, it was observed that certain cluster patterns performed better against the mass flows, within a given domain of angle between clusters and flow lines. It was also observed that the two evaluation criteria contradict each other: As mitigation promotes clustering of units, self-shading competes to pull units apart, thus restricting mutual shading between units.
It was also noticed that the patterns were developing to form similar arrangements,where we would attain mostly North facing facades. Thus weighted distribution inside circle packing algorithm was added to attain south -facing facades, as the south sun in these cold deserts keeps the building warm during winters.
FURTHER DEVELOPMENT
The final individual(Refer Fig| 07.07) is taken forward into further development. As every program has a unique set of requirements, the morphologies are explored further, where morphological variation in terms of architectonics are embedded within the system, and detail plans are drawn for standard units. Also, other morphologies (besides dwelling units) are designed and explored further.
Previous Page: Fig| 07.06 Each diagram depicting various individual generated during the experiment. (Source: Author).
Current Page (top): Fig| 07.07
Top view of the final individual taken forward for further development (Source: Author)
(Source: Author)
(Source: Author)
AGGREGATION POSSIBILITIES
Autonomous building types aggregated to follow discreet programmatic functionalities required to sustain a settlement in the high altitude dry climatic regions with relative small alterations.
The following pages elucidate morphological variations, dictated by social & spatial requirements on per person basis. Since the economics of the region is a direct outcome of tourism and agriculture along with material sites (proposed) and small business families, a modular system is devised, adhering to different parameters and site conditions. Material requirements, automation and performance (resistance to mass flow) of the morphology is considered as evaluating criterion’s for ranking these morphologies. Many non-conventional functions such as markets and greenhouses are developed that would stabilise food production and distribution.
Aggregation and placement play the most pivotal role in mass flow mitigation. Thus the cluster formations are first optimised for post debris and flash flood scenarios. Although the major flow is detained through the landscape setup described in the previous chapters,the worst scenario is considered. Morphological variation also arises due to terrain dynamics, which have been addressed while designing units on site.
Current Page (right): Fig| 07.08
Diagram depicting sequential aggregation of two distinct morphological primitive types. These morphologies can be manipulated to sustain multiple functional requirements.
Next Page: Fig| 07.09 Parameters for differentiating morphologies for structural and environmental performance.
SPANNING SEGMENTS
The directional curves represent the linear layout arrangement where the line of each segment within the discontinuity dictates the unit dimensions. These curves are an outcome of mass flow mitigation analysis. The maximum span possible with Type(1) morphologies is 6.0 m, as the maximum length of poplar extracted is 8-10 m. With type(2), it is 7.14 m diameter, with the maximum bag size available.
The spatial packing logic is extracted from various settlements thriving within the region. In both cases it is done with regards to the various space requirements. Intersection of various units giving rise to differential patterns within the morphologies is indirect outcome of ecological parameters. The redundancy allowed by the material provides multiple size domains for resulting morphologies with areas ranging from 30 -200 m2 respectively.
Each Span is designated with its corresponding heights within the established range of 3-6 m in either of the proposed types, as extracted from material constraints. These heights can be manipulated further depending upon the functional requirements.
RENDERING & FENESTRATION
Various fenestration patterns are atributed based upon the unit orientation and program requirements. Since the climate requires less opacity on the southern side for winter sun, patterns have been generated to maximise entry of natural daylight into the dwellings.
Explaining difference in material usage and internal space relationships for two distinct proposed unit types.
EXISTING
Area (m2): 30-45
Earth Required(m3): 300
Wood Required(m3): 50
Current Page (above) Fig| 07.10
Diagram depicting sequential aggregation of two distinct morphological primitive types. These morphologies can be manipulated to sustain multiple functional requirements.
(Source: Author)
PROPOSED Type(2)
Area(m2): 102
Earth Required(m3): 125-210
Wood Required(m3): 11-25
PROPOSED Type(1)
Area(m2): 79
Earth Required(m3): 230-500
Wood Required(m3): 12-50
DESIGN
The proposed”dwelling” morphologies can be classified into two types: Type 1 & 2, while type(1) caters to small business and families that do not work within and around home. The type(2) caters to a population that require storage of animals and agriculture produce.
ATTRIBUTES AGGREGATION
Aggregation is based on proximity to debris catchments and forest areas, since both morphologies have different construction considerations and material requirements. The morphological variation is also dictated by the availability of material type.
Type(1) are primarily flow channelizing morphologies that consume more timber (hardwood) from poplars tree as compared to type(2). These dwellings are usually built near material sites and poplar woods, to reduce transportation of equipment. The use of timber allows for further adjustment to various degrees of heights (3 - 10) , the system can be arrayed to the length of the wall if needed, yielding higher densities. The side walls are constructed out of thick stone or earth. Thus taking benefit of the high thermal mass. The Sunken interiors absorb heat from the ground, adding to the thermal conditioning inside (Refer Fig| 07.11). A removable straw and sun-dried earth based covering are though of that can be moved from the timber scaffolding allowing for different.
Type(2) Primarily due to its compressive strength allows for diverting mass flows; these dwellings are a combination of catenary domes with span varying between(3.15-7.2)m. The intersection of domes created internal buttressing within the structure, providing additional strength. Each span is designated its established height according to the stacking effect, and earthbag size used. Primarily designed as agriculture dwellings this house a grain storage and animal storage. The sunken interiors limit the height constraints, allowing for faster and easier construction of these autonomous units. The animal shelter acts as a heat chamber radiating heat into the interiors.
Current Page: Fig| 07.11
Sectional view of a typical type(1) unit.
(Source: Author)
Current Page: Fig| 07.12
Sectional view of a typical type(2) unit.
(Source: Author)
07-7a
CONFIGURATIONS (TYPE-1)
The aggregable units can couple together as larger units for various family sizes , providing redundancy in system for numerous configurations..
SPATIAL ATTRIBUTES
07-7a.1 07-7a.2
TYPE-2a
People: 1 Family (4 persons)
Area(m2): 18
Material(m3): 230 (earth), 30 (wood)
TYPE-2c
People: 1-3 Families (8 persons)
Area(m2): 41
Material(m3): 300-350 (earth), 40-53 (wood)
SPATIAL ATTRIBUTES
TYPE-2b
People: 1-2 Families (6 persons)
Area(m2): 28
Material(m3): 260-320 (earth), 30 -48(wood)
TYPE-2d
People: 1-4 Families (12 persons)
Area(m2): 57
Material(m3): 530 (earth), 60 (wood)
07-7b
CONFIGURATIONS (TYPE-2)
Drawings explaining possible configurations based on spatial requirements and material utilisation.
SPATIAL ATTRIBUTES
07-7b.1
TYPE-1a (Family Only)
People: 1 Family (4 persons)
Area(m2): 23
Material(m3): 230 (earth), 30 (wood)
TYPE-1b (Family Only)
People: 1-2 Family (6-10 persons)
Area(m2): 45
Material(m3): 450 (earth), 80-100 (wood)
SPATIAL ATTRIBUTES
07-7b.2
TYPE-1c (Family +Lodging)
People: 1-2 Family (6-8 persons)
Area(m2): 39
Material(m3): 300-350 (earth), 40-60(wood)
TYPE-1d (Family + Lodging)
People: 2-3 Family (10-12 persons)
Area(m2): 72-89
Material(m3): 680 (earth), 120-150 (wood)
07-7c
INTEGRATED PROPOSAL (SUMMER)
As the region experiences a very limited period of summer, most of the external physical activities happen simultaneously. While debris collection and channelisation is an ongoing event, agricultural practices on different slopes are adopted to couple with designated forest clusters.
The aerial graphic of the settlement in summer tries to highlight these multi-disciplinary activities, as these form the primary source of resource management and preparation for the local inhabitants.
Agricultural farmlands Primary Water Catchment
Water Channels
Retention structure
Agro-forestry
Debris Channelisation
Terraced farming
Catchment Surface
Pastoral Growth
INTEGRATED PROPOSAL (WINTER) 07-7c
In winters, the terrain transforms into a cold desert, where most of the activities take place in warm interior spaces. While native winter crops are grown on steeper slopes, agricultural farmlands on flatter slopes are replaced by naturally occurring winter vegetation. Excess water collected from precipitation and snow melt in stored in the form of artificial glaciers in the rain shadow regions. Catchment surfaces which were initially constructed to increase surface run-off now become dense snow fields as the snow accumulates on intermediate levels.
This graphic scales the different landscape elements and social spaces that weave the settlement into a symbiotic relationship to survive the harsh conditions of winter.
Snow accumulation
Artificial Glaciers
Educational Complex
Winter Markets
Terraced farming
GREEN HOUSES
Green houses developed as a seasonal structures to be utilized on potential agricultural field, with high higher threshold of direct sunlight hours.
Removable U.V sheet, used to trap heat during daytime
Sun Radiation Rose
Max Angle(degrees): 79
Max Radiation(Kw/m2): 53.40
Maximum Radiation: 180deg N
Proposed Design
Max Angle(degrees): 10 to 38 deg
Material earth(m3): 230
Material wood(m3): 30
Removable Lightweight Timber structure with slant roof angle to increase surface area for heat gain
Morphology showing 3m high earth-bag or stone walls with one side completely open for direct solar gains
STRATEGY
For food production year around, passive solar greenhouses are developed. The idea was to create spaces where agriculture practices were not hindered by climatic influences. Thus a temporary enclosure is proposed, were a series of timber section are places to form a sloping roof, which gets covered with a recycled U.V. polythene sheet (Refer Fig 07.16). These timber sections are supported by an earthbag walls.
CONSTRUCTION
Previous Page (above): Fig| 07.13 Solar greenhouse in the barren mountains of Ladakh, India
Previous Page (below left): Fig| 07.14 Image showing a passive solar green house, in the valley of ladakh. (Source: https://s-media-cache-ak0.pinimg. com/736x/7b/10/24/7b10243af8c177b3a12b90eec9d700be.jpg)
Previous Page (below right): Fig| 07.15 Image showing the insides of a passive solar green house, in the valley of ladakh. (Source: https://s-media-cache-ak0.pinimg. com/736x/7b/10/24/7b10243af8c177b3a12b90eec9d700be.jpg)
Current Page (above): Fig| 07.16 Diagram showing various parameters considered while designing greenhouses in the valley (Source: Author)
ARRANGEMENT
The earthbag wall was positioned such that longer axis of the building would always line on the east-west plane. The north facing side of the wall was stretched the highest to avoid the diffuse cold light from the north. A sloped roof configuration covered with U.V. polythene sheet was proposed which would trap the heat inside and protect crops from long wavelength U.V rays. On the inside, the east-facing wall was painted white to reflect low angle morning sun onto the crops, and the rest were painted black to absorb the setting sun. This was to take advantage of the low angle setting and rising sun. Additionally, the structure is deployable and can be packed together during summers (Refer Fig 07.13), when sunlight is in abundance. But as projected through our calculations done during previous chapters all year around greenhouses are vital in accommodating food requirements of the growing settlement.
The positioning of greenhouses is done over sites having a maximum number of sunlight hours. and low risk value from landslides. These structures can pop up in no time; the earthbag walls act as false work serving as partition walls between agriculture fields when not in use. The number of green houses required for this this test is calculated through the estimations (Refer page 195).
36(degrees)
07-9 EDUCATIONAL
Understanding the various social and spatial configurations that binds the locals as a community.
Schools in Ladakh usually serve as a focus of communal activities, with monthly gatherings followed by usual celebrations. The education of this region has been considered of prime importance. In the year 2005 Arup & Associates were commissioned to design Druk white lotus school. This educational complex held day boarding and hostel facilities. The building was one of the few to survive the 2010 flash floods.
AGGREGATION
(Source: Author)
Next Page (top): Fig| 07.18 Render of the new proposed educational street on the test patch.
(Source: Author)
Next Page (below right): Fig| 07.19 Image depicting the morphological variation in educational morphologies.
(Source: Author)
Next Page (below left) Fig| 07.20 Diagram depicting the architectural sections and plans for the proposed building.
(Source: Author)
DIMENSIONS
An interpretation of this function is proposed by adapting the building type into a combination of clusters, that enclose an open space in-between. The classrooms are similar to Type(2) units, where multilevel studios are possible, allowing for higher density. The circulation being linear is easy to access. Th sub level studio spaces can be used for younger students. The administration block is similar to type(1) unit, here no below grade spaces are provided, rather a mezzanine for more storage and archiving.
Typical dimensions were extracted during on-site visits and it was estimated that the school considers 1.5 m2 /student as the benchmark for spatial estimation.
Current Page (above): Fig| 07.17 Picture depicting weekend play gathering in Druk White Lotus school , Leh ,Ladakh.
Entrance
Multi purpose area
Classroom
Corridor
Play Area
07-10 COLD DESERT MARKETS
Exploring the proposed typology as an aggregated medium to support tertiary activites.
Current markets in Ladakh serve primarily as tourist attractions acting as major contributor towards annual revenue. With the emphasis on a new localised food and resource production strategy via a network of greenhouses a different type of commercial space was required. Thus an indoor market space was considered to facilitate the selling of fresh farm produce and perishable goods. Since the markets would be decentralised and become apart of the urban fabric; more spontaneous exchange between buyer and consumer could be possible as goods transport time would reduce considerably.
AGGREGATION
Next Page (below right) Fig| 07.19 Image depicting the morphological variation in market morphologies.
(Source: Author)
Next Page (below left) Fig| 07.20 Diagram depicting the architectural sections and plans for the proposed building.
(Source: Author)
An interpretation of this function is proposed by extending the type(2) dwelling units. The previously designed unit was divided into body plan, the main body which has permanent shops on different levels. The corridor space that transforms into a street market under the sloping roof and the extended bay that works as a deployable structure an extends into extra space to set up temporary shops on certain days.
DIMENSIONS
Main body: 5-8m deep and 4-10m ( depending upon the back wall size)
Corridor Space: 3-6m deep and 4-10m high (depending upon timber sections length
Extension Space: 3-4m deep and 3m high
SPATIAL ATTRIBUTES 07-10.4
Slope Failure Line
Deep Root Zone Depths
Debris Channelisation
Hybrid Poplars
Sub-Level to control heat loss
The above section illustrates different functional aspects that contribute in reducing various ecological effects on the landscape. Strategies to control surface run-off and slope stabilisation through intercropping, agro-forestry and deeper foundations are employed to enable maximum control over the initial slope failure plane.
The emergence of clusters is solely based on occupation and function of the inhabitants. This interface is dependent on the proximity to material resources and terraced farmlands. The density distribution is dictated by the permanence of structures on site, where seasonal climatic changes play an important role in determining individual structural durability. In winters, when agricultural productivity is low, the temporary structures can be easily converted to greenhouses for their relatively higher thermal performance, while settlement expansion and construction continues as an annual process.
Debris Channelisation
Hybrid Poplars
Sub-Level to control heat loss
Current Page (above) Fig| 07.26
Sectional Elevation depicting longitudinal profile along the length of the site.
(Source: Author)
The temporary units anchored to retaining walls can also be eventually converted to permanent dwellings based on material availability. Low floor heights signify spaces for food storage and animal shelter. The flexibility of spaces both internally and externally, results in a comprehensive settlement pattern that can adapt to the existing conditions of climate change and plan for future scenarios of resource conservation. DESIGN FLEXIBILITY 07-10.7 07-10.8
The above section focuses on showcasing secondary landscape elements that increase the efficiency of securing material resources. Catchment surfaces and earthbag deflectors allow for increased water collection in the conservation ponds, which can be frozen and stored in the form of artificial glaciers. Internal variations in dwelling types to increase thermal performance are illustrated with varying floor heights based on the spatial configuration of the unit.
Type 01 Unit
Type 02 Unit
Modified Raft Foundation
Effective Root Zone depths
Gabion Retaining wall
Current Page (above): Fig| 07.27
Sectional Elevation depicting transverse profile along the width of the site.
(Source: Author)
07-11
CONCLUSIONS
Evaluation of design proposal and research advancements in the Design Proposal chapter.
FLOW MITIGATION
The experiment “Flow mitigation” on page 194 validates the idea of autonomous building clusters in the Cold desert environment, where surface runoff and residual flow discharge can be measured on a topographical object
The use of flow dynamic analysis (at the local scale) lacks the integration of trees and other street furniture for mitigation. However, this method has been useful in observing accumulated debris areas on the topography as a result of building density and orientation.
SOLAR ACCESS
The sun is a precious resource, as it is the primary source of thermal gain and both building envelopes and the outdoor surfaces should benefit as much as possible from it. Although solar access to open ground conditions in relation to a building, clusters have not yet been evaluated; this would be a significant advancement.
Being a cold desert type region, self-shading and solar access have been used as contradicting criteria for evaluation. Positioned in the northern hemisphere the obvious solution is to orient the long axis of the building East-West, although this creates a higher instance of longer shadows over the ground, resulting in excessive self-shading. This was overcome through geometrical variation in the morphologies,and locally through the building envelope, where the fenestrations could be manipulated depending upon seasons.
Given the extreme climate and harsh terrain, the system has been assembled under the assumption of creating comfortable spaces through secure enclosures. Thermal heat gains from various sources have been taken into account, especially from the livestock. The replacement of animal shelters is crucial in the regions, which have been placed on the sub-level of the dwelling; this helps warm the floors above. Living spaces have been provided on below grade levels to isolate the room from external temperatures, which resulted in confinement of space and created a new issue of light and ventilation, that was dealt accordingly through flow analysis while designing.
The cluster level evaluations provide sufficient techniques for solar and debris flow optimisation, Although building optimisation in terms of orientation and local scale geometric modulations could yield higher performative results.
Networks have only been explored in terms of a settlement scale and not been addressed during cluster level agglomerations, the reason being , that local level paths are convenience and choice based in these regions
Since there is no one fixed route a single destination. Although, least gradient paths and other syntactical analysis can have significant impact in regularisation of the networks.
CONCLUSIONS
09-1 CONCLUSIONS
Critical assessment of the various aspects pertaining to the project; in terms of understanding its potentials and limitations to predict its paramountcy in the discipline of Architecture.
RETENTION STRATEGY
The rigorous experimentations and sampling done from on-site data mining to creating virtual mathematical models to predict debris scenarios can drive similar approaches in complex terrains. Various computational techniques like Fluid dynamics, genetic algorithms and agent-based modelling can be integrated within the base mathematical model to develop remedial strategies.
However, the feasibility of this approach relies highly on predictive modelling and interpolated statistics, so actual results are subject to variation, although this method resulted in 73% height reduction of debris deposition in the valleys, as per the post-simulation results. The deviations from the achieved results can be debated on various levels for future integration of multiple disciplines such as Cartography, lithology , statistics and Architecture to result in new emergent solutions in generative landscapes.
HYDROLOGICAL STRATEGY
Typical hydrological models are limited to conventional computational methods that primarily relies on topographical understanding ( model resolution) and do not take into account the seasonal variations. The research thus attempts a seasonal integration of hydrological source as a viable strategy to maximise water conservation in cryic regions. Given the fact that local emergent technologies of freezing water by exploiting existing variations of surface temperatures are already being implemented, the project aims to capitalise on the same within the limits of the present computational intelligence.
EMERGENT LAND FORMATIONS
Developing a multilevel genetic algorithm to determine resource consumption-production rates against varying population densities. Provided concrete evidence that these regions are suitable only for low to medium density ranges. The incremental outburst of population migration cannot be sustained beyond a certain threshold in these fragile ecosystems. Though maximum efforts were put in to exploit the terrain to its fullest potential, where each cell on the terrain was assigned a suitable task to perform and contribute to the production cycle, the results were unsuitable to the current trends of population growth. However, the results reflect only a 10-year growth model, the long-term effect of this approach may prove to be subjectively detrimental to the existing context.
MATERIAL/CONTEXT
On-site interviews and field studies provided requisite information that indicated towards a rational design approach that takes into account the material economy and opinions of the people. Thus a conscious effort was made to approach the design from a more contextual based theme. However , the contextual parameters extracted during tissue sampling were used to evaluate the designed model in virtual environments.
The proposed morphology makes maximum usage of the naturally abundant (in this case recurring) material ”debris” as the primary source for construction. The simplicity and flexibility that earthbag stacking can provide as opposed to stagnant architectural styles significantly higher, both in thermal and structural performance. The distinction of building type both in terms of material and function contributes to a higher probability of self-sustaining community that can cap logistical challenges faced currently. However, the current autonomous nature of the units in terms of its geometry can be explored , optimised and evaluated as future developments depending on the success of its parent.
Critically evaluating tvarious aspects of the project for further advancements.
LIMITATIONS
09-2.1
-The research proposal relies heavily on predictive modeling and scientific datums. It can only approximate the actual scenario, thus results may vary accordingly. Efforts have been made by extracting data from scientific organizations and through utilization of known/proven techniques.
-Due to heavy computational load, the design development is limited to scalability. Only a patch could be developed where all strategies are coherently integrated. Thus design interventions on a larger surface is a challenge and would require sophisticated analytical tools beyond conventional computation techniques.
-The accuracy is limited by cell boundaries and is subject to the cell size being analyzed. As the scale increases, the cell size decreases, affecting the accuracy of analysis significantly.
-The existing tissue has evolved out of experience, adaptation and aspirations of locals. The design proposal takes into consideration only the ecological aspects.
-The specificity of the proposal is very rigid. The success of this model in a different terrain/ context is highly speculative. It is not completely deterministic and is limited by the flexibility of unpredictable changes.
FUTURE DEVELOPMENTS
09-2.2
-The current hydrological and agricultural strategies are developed on a regional scale where the aim is to maximise overall productivity. The water management strategy could be further improved to a more localised level where every unit can harvest water from snow accumulation and precipitation.
-Within the proposed autonomous clusters, different unit aggregations for program distribution could be explored to adapt to different spatial requirements.
-An integrated network strategy can be established to determine proximity radii from dwelling units to resource points.
-The proposed system could be evaluated on network hierarchy, wind flow and CFD analysis.
CRYIC TRANSFORMATIONS
09-2.3
Cryic transformations is a research that revolves around the idea exploiting the inbuilt intelligence within existing natural systems. This intelligence seems to exist at various levels in the ecology, such as, seasons, thawing ,microbial breakdown and patterns observed in micro-climatic changes.
The project delineates various approaches to utilise these existing mechanisms for future settlement growth within a given set of domain “the cryic regions”. Although being an experimental research, the project displays multiple work-flows that can be adapted as an approach towards analysing different terrain and climatic models to device future growth systems.
The outcome is a model, that consumes and replenishes itself through collective work of definitive strategies, which were carefully driven through mathematical calculations. The project attempts at debating the domain of architecture in the future, where buildings would be seen as standalone creations, but rather a part of a symbiotic system, inside which buildings are an integral part of.
DESIGN DETAILS
09-1
OVERVIEW
Design proposal explaining unit level details and sectional elevations.
This chapter illustrates the broad variation in assembly of two distinct unit types that emerge from the nearest possible material location. Since earth bag stacking, provides the opportunity of constructing flexible shell morphologies, it is important to note that the system adheres to various curved formations depending on the degree of deflection required to divert residual mass flows.
The variation in internal spaces and their integration with existing landscape elements is discussed through detailed sectional variations. The flatter safe zones that emerge through initial clustering strategies form recreational spaces like cold desert markets and public parks. These spaces are of valuable importance in a remote region where natives are more dependent on community based lifestyle rather than technological addiction.
Apart from high thermal performance and low maintenance issues, the dwellings embed passive solar harvesting strategies to reduce conventional energy consumption in the region. These notions are already being developed at a localised level and can be further elaborated through intelligent positioning mechanisms.
UNIT TYPE 01 09-2
Assembly sequence and internal spatial organization of the first type that deflects residual debris flows
Earth filled polypropylene bags, fixed to the foundation walls coming from below.
Foundation walls constructed from random rubble masonry or gabions acting as a ring beam holding the structure in-place.
Ground floor plate-extents
Sub level for night activities and fire hearth acting as a primary heat chamber for radiating heat all around the house.
The following diagrams represent the two dwelling types in detail where the architectonics of the designed structures are explored. The Type(1) unit is built upon foundation walls, constructed from random rubble or gabions as dictated by the availability of the material. The fenestrations on the envelope are constructed with s set of spacers , resulting in circular or elliptical openings. The Type(2) unit being a light weight structure is designed as a plug-in structure to fit into any existing retention structure or newly constructed walls. This system is protected with timber framework that forms the roof over the structure. The roof is fitted with modular panels that can be moved as per desired sunlight penetration. The following sections explores various architectural systems and details that would help construct and ensure the feasibility of these units.
Current Page: Fig| 09.01
Diagram showing exploded view section of unit type 01 (Source: Author)
Current Page: Fig| 09.02
Diagram showing exploded view section of unit type(2) (Source: Author)
UNIT TYPE 02 09-3
Assembly sequence and internal spatial organization of the second type that channelises or contains residual debris flows
Composite earth panel with straw and hay , tied together with thin dry earth panels.
Wooden Rafters supported from earth wall, providing excess surface are for excess direct solar gain.
Earth wall, acting as primary load bearing element that supports the entire structure
Earth bag wall to retain heat inside the building at night due to its high thermal mass. Sub level for night activities and fire hearth acting as a primary heat chamber for radiating heat all around the house.
TYPE 01: UNIT DETAILS
Detailed drawings explaining assembly logic of critical architectural elements as recorded earlier from previous studies.
Earth-bag tubes
TIMBER STAIRCASE DETAIL
Vertical accessibility has become a priority in Leh-Ladakh since, most of the housing units are located on multiple levels. (Refer Unit Level Settlement Study) The above drawing illustrates possible ways of utilising timber sections to be milled as rectangular sections (rafters) that can be inserted between two consecutive earth bag courses. The vertical risers, bolted into the treads hold the entire assembly in place with the treads pulled back towards the outer face to balance the cantilever forces. Additional stifness is applied with bracing underneath. The use of staircases in the proposed unit type is uncommon since most of the domes are single ground structures. Stables and larders, which were initially on the lower levels, now form a connected part of the dwelling on the same plane.
09-4.1
Milled Timber treads
900-1200 mm
Current Page (top right) Fig| 0.9.03
Diagram showing staircase fixture in cut section of unit type 01
(Source: Author)
Risers bolted to treads
Corner Detail at "A"
Earthbag course
Wooden planks (tread) L-plate (connector)
Timber Bracing (elevation)
The door design is a simple arrangement that requires comparatively less material and duration to assemble as opposed to the initial door frames that had heavy ornamentation. These doors could be deployed in temporarily utilised buildings like guest-houses and storage spaces. Owing to the flexible nature of earth fill construction, various types of door designs are possible, although only a typical one has been illustrated above.
Current Page (top): Fig| 09.04
Diagram showing exploded view of a typical door fixing detail in earth bag construction of unit type 01.
(Source: Author)
Earthbag vertical edge
Cement Stabilised Bags
Typical Corner Joint (tongue & groove / dovetail)
Metal/Timber Jamb
Timber Framework
Chicken Wire cradles for increased adhesion Keystone (earthbag)
Interior adobe/wood floor
6" above grade
FOUNDATION DETAIL
Insulated foundations are most effective in cold and wet climates. Since this unit type contributes to deflecting residual debris flows (that have adequate water content ), the foundations are more prone to external water seepage. Thus an additional layer of insulation and external plastic sheeting (recycled) is required to ensure durability of the structure.
Metal flashing (galvanised)
Optional 8 mil Plastic sheeting
Current Page (right): Fig| 09.05
Diagram showing insulated earthbag foundation for unit type 01.
(Source: Redrawn from Hunter and Kiffmeyer, 2004)
Standard Earthbag courses
J-Metal weep screed
2" rigid foam
Gravel trench foundation
Insulation Layer
CIRCULAR WINDOW DETAIL
Circular windows are relatively easy to install in earthbag architecture. The primary reason for employing this window type is to maximise solar access in the interiors. The vertical pivot joint allows for nearly 1800 or more of rotational movement which can be adjusted according to the direction of the sun vector. The uni-directional opening of typical Ladakhi windows allows entry of light for only half a day. Thus this window type can be efficient in harnessing maximum solar access for an increased duration in both summers and winters.
Fabricated wooden transom
Vertically fixed timber pivot
Custom made steel framing
Double Glazing
250-300 mm
Current Page (right): Fig| 09.06
Diagram showing exploded view of a typical door fixing detail in earth bag construction of unit type 01.
(Source: Author)
TYPE 02: UNIT DETAILS
Detailed drawings explaining assembly logic of critical architectural elements driven by material properties.
FLOOR TO WALL CONNECTION
The random rubble stone wall acts as a monolithic support that holds the side wall and timber battens into a compact built-in assembly. The battens are inserted into the retaining wall with a c/c distance of 500 mm and further cross braced with wooden rafters for additional strength. Standard floor boards as were traditionally used, can be bolted close together to cover the framework below. As the proposal is contextualised in a cold desert biome, the need for waterproofing is comparatively lower than sub tropical architectural designs. This also eliminates the need for skirting as the assembly is designed to be temporary and light in weight.
Earthbag side wall
Timber Battens
Cross Rafters
Wooden floor boards
Current Page (right): Fig| 09.07
Design detail showing connection of timber framework floor to external walls.
(Source: Author)
Random rubble retaining wall
Joist Connection
Corner Detail at "A"
(Source: Author)
SOLAR PANEL ASSEMBLY
Taking advantage of diagonal surface exposure to install solar panels.
As solar panels are already being installed at a large scale in the region, this initiative is integrated into the type 02 unit. As 60% of the diagonal walls in the proposal are facing south, the incident solar radiation is the maximum on these faces. The detail above illustrates possible fixing of solar panels to the diagonal framing. The solar panels, being light in weight can be easily removed in winters and installed again in the summer to harness and utilise solar energy for daily activities.
Current Page (right): Fig| 09.08
Exploded view showing solar panel assembly for unit type 02.
Solar Panels
Dry wood chip boards
Timber Framework
Typical timber joinery
Typical lap joint
Mortice & Tenon Joint
REFERENCES
REFERENCES
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Inference: Minimum ground frost for only 2 months annually
X Axis: Month
Y Axis: Temperature in 0C
LEH- DIURNAL VARIATIONS
X Axis: Month Y Axis: No. Of Hours
2.5 (Source: Generated through Ecotect Analysis 2015) Monthly Diurnal Average of Leh- Ladakh District indicating annual temperature variations.
Fig| 2.6 (Source: Generated through Ecotect Analysis 2015) Global Solar Radiation - Average Daily Graph of Leh-Ladakh. The legend indicates Watt per meter square amount of radiation.
Fig|
CROP CALENDAR LEH- CROP STUDY 11-5
LEH- AGRICULTURE AND CROP PATTERNS
Crop coefficient curve showing Kc change at different season stages (modified from ALLEN et al. 1998: 100)
This level has the smallest openings in the house with nearly negligible light penetration. The actual function is exclusively structural.
A central aperture (thogskar) in floor slabs dissipates smoke produced. Dual function of combustion and heat gain achieved. All openings are oriented towards South or East to capture direct solar access.
Thabsa (Fireplace)
Room
Chagra
Donkhang
Nyimalhakhang
Shelkhang
Yab
This level barrier free to harness direct sunlight in summer and provide social spaces in winter. It also serves as a storage and protective space for resources.
