The Intertwined is a flood-resilient housing proposal for Sindh, Punjab, and Balochistan in Pakistan. These regions are primarily desert, with a narrow strip of greenery present along the Indus River. The Indus Valley provides not just water in the desert climate but also alluvial soil, so most people live in earth-based building along the Valley. When the Indus River rises during the monsoon, it poses a critical problem, as most earth buildings collapse after being submerged for long periods. Unfortunately, climate change has resulted in more destructive flooding, leading to a higher number of people being affected and displaced.

 

Based on an understanding of the issue and context, this project is planned to show how a flood-resistant design and technology can be created by utilising local materials and crafts. The flood-resilient technology is developed from three major research approach–architectural, anthropological, technical approach. The multi-disciplinary approach helped to examine a complicated issue with a holistic perspective and develop the flood-resilient technology, considering its impact on the local community.

 

An anthropological study of Sindh, Balochistan, and Punjab is interpreted as an architectural form. Reflecting the country's strong clan society, this project proposes a clustered form of housing, where 4 houses are connected, having a central communal courtyard. To minimise flood damage, the four houses are strategically located in the centre of the plot, away from the housing fence, and they are built on a raised platform 540mm above ground level.

 

Each room’s size and function are designed based on the vernacular housing layout. Each household has their own farm, and the ground floor comprises a storage area, animal shed, toilet, and open kitchen. A top floor has a bedroom and terrace. As a semi-outdoor living room, the terrace allows a free communication between family members through a central courtyard. In the event of flooding, the terrace could serve as additional storage space to move items from the storage space on the ground floor. Also, it could be converted into an extra room later on if family members increase.

 

The connected roofs of the houses echo the profile of rippling waves. The butterfly roofs aid in collecting rainwater following its ridge, and this water is transported to the cistern in the garden. Each household can use this water in case the groundwater is contaminated during a long flooding period.

 

The flood-resilient technology is developed using locally available materials; soil, fabric, bamboo, and palm tree leaves are locally available in Punjab, Sindh and Balochistan, and local crafts have developed with these materials. Considering the scarcity of timber as a formwork material in the region, locally available fabric is proposed for building formwork for rammed earth. Along with fabric, palm leaves are also used as an essential material to create flexible formwork for rammed earth. Weaving palm-leaf is a local craft of Sindh and Balochistan to create household items. For this project, the weaving craft is promoted not just to build formwork for rammed earth but also to produce a protective layer for the rammed earth wall from erosion during extreme flooding. In this way, local palm leaf weaving technology is reinvented as an innovative flood-resilient technology. Another locally available material is bamboo. Thanks to the flood-tolerant feature of bamboo, it is widely found in the floodplains, and it can be used as an alternative to timber. Therefore, for this proposal, bamboo is used for not just structural materials but also as frames of formwork for building rammed earth.

 

 A novel aspect of the flood-resilient technology is shown in the construction process of rammed earth. While involving local crafts, local materials are strategically employed to create the flood-resilient structure, beyond the conventional use of them. 

 

As a flood-resilient strategy, the houses are designed to have both a defence and a recovery system. These two different systems work in response to different levels of flooding; for a low level of flooding, a defence system works, whereas for a high level of flooding, a recovery system operates. When a flooding level is moderate, the houses can be protected by having a 540mm raised platform and lime-stabilised foundation, plinth, and wall (the wall is stabilised up to 900mm high from the raised platform). However, when a level of flooding is high, the houses let in water but dry out soon once water recedes. This system works by placing gravel-filled layers within rammed earth walls. Being different with clay, gravel does not absorb water, so it dries out quickly once water recedes. By utilising the property of gravel, the gravel-filled layers are schematically devised to stop rising damp; therefore, the layers are placed in two locations - 180mm and 900mm high from the raised platform. The low layer is to stop rising damp from the ground, whereas the 900mm high layer is to stop moisture rising above the unstabilised rammed earth wall in case high flooding happens. Considering the highest flooding depth on record in Pakistan, the 900mm high layer is placed at 1440mm above from the natural ground level. The layer comprises loose gravels that are interlocked by fabric string without using any binders. Therefore, it facilitates drying the rammed earth walls once the water recedes. This structural detail was planned as a solution to protect the rammed earth structure from inundation and also recover the structure quickly after flooding, taking advantage of the property of soils. 

 

The flood-resilient technology of this proposal is invented, putting a focus on the construction process. The technology allows to involve diverse local crafts to the construction to produce a flood-resilient structure. This collaborative construction process would be significantly important in post-disaster conditions where most people lost their job after the disaster. Therefore, the proposed flexible formed rammed earth technology could play an essential role in providing a job opportunity for displaced people after flooding and also empowering them to build their own flood-resilient homes with locally available sources. 

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