Flood-resilient Design and Construction according to flood depth
- Scarlett Lee
- 2 days ago
- 2 min read
Flooding has been originally an important annual event for agriculture by carrying fertile soil. For the country like Pakistan where agriculture and textile industries are a fundamental economic asset, most people in Punjab, Sindh, and Balochistan have been living along the Indus River by using the water sources of the Indus river for farming or textile industries. However, climate change has rendered flooding more disastrous. For the flooding in 2022 which had the historically high precipitation, most territories of Pakistan were inundated. Most vernacular earth dwellings in the floodplains in Pakistan are highly prone to collapse by destructive flooding.
The housing proposal Intertwined is designed to show innovative low-tech construction methods to address flooding. Considering the desert climate of Punjab, Sindh, and Balochistan where resources are scarce, locally available materials - soil, fabric, palm leaves, and bamboo were utilised for building flood-resilient housing. Because adobe and cob construction - vernacular earth construction methods in Pakistan - are vulnerable to rainwater and structurally weaker, rammed earth made of fabric formwork is proposed for flood-resilient construction.Â
Given the 900mm-flood depth, which was the highest in the year 2022, different flood-resilient design was created according to flood depth. For the annual flooding, usually 200mm depth, 540mm-raised platform protects the rammed earth house by usual flooding. The platform close to the rammed earth wall is filled with gravel to drain rainwater easily. The rammed earth wall is built on lime-stabilised rammed earth foundation and plinth. The ground floor is filled with gravel to drain water quickly. Instead of DPC (damp proofing course), loose gravel intertwined with string are placed on the rammed earth walls, and they are in 180mm and 900mm high from the raised platform. Utilising the property of gravel that does not absorb water and drain it promptly, the gravel-filled layer protects unstabilised rammed earth wall above 900 from water ingress. This layer does not stop water entering to the house in case of high flooding, but helps the earth structure drying quicker than rubber based DPC by ventilating air when water recedes.
Woven palm leaves are wrapping around the lime-stabilised rammed earth wall up to 900mm high from the raised platform to protect the wall from floating debris. Palm leaves have been traditionally used for thatched roofs, but these roofs have a short life span and it is difficult to repair during prolong flooding. Instead of following traditional construction methods, corrugated metal sheet is proposed as a roofing material. The project Intertwined repurposes palm leaves as a flood-protective layer while involving locals' weaving craft related to the material.
As a flood-tolerant plant, bamboo is commonly found in the floodplains. Therefore, bamboo is used for construction materials for flexibly formed rammed earth as well as structural materials (The construction process is shown in the video.)
Therefore, the project Intertwined was created to show how flood-resilient earth houses in Pakistan can be built with local materials by involving local crafts.
The detailed information of the project Intertwined can be found from the link below.
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