An Approach Towards a Sponge Cityscape, Khulna, Bangladesh | Masters Thesis on Urban Landscape Design

Site Context

Bangladesh is a densely populated, low-lying, riverine country situated in South Asia. Bangladesh’s topography is greatly influenced by water, which primarily originates from the Himalayas and rainfall.

Khulna, Bangladesh’s third-largest city, is situated on the Bhairab (Rupsha) river’s bank 200 kilometres from the country’s capital. The effects of climate change have caused the normal situation to change daily during the last few decades. In Khulna’s rural and urban areas, flooding and waterlogging are becoming more common due to rising sea levels and increased rainfall.

Design Process

An online survey conducted among various groups of people in Khulna city has identified different aspects of flooding, waterlogging, and climate change. The main emphasis for waterlogging and flooding is on man-made causes. Furthermore, water management and natural drainage systems are being significantly impacted by climate change. Once the primary stormwater carrying route, the Moyur River is severely affected by illegal encroachment, a lack of waste management, and a lack of planning policies.

Analysis was done on the pattern of vernacular housing and how it changed over time. Rapid urbanisation caused the harmony of the vernacular pattern to vanish from ponds, gardens, courtyards, and homes. It’s become a concrete city at this point.

Final Outcome

Given the circumstances, the “Sponge cityscape” water-responsive landscape design solution would be an effective means to alleviate the situation. Development in a conventional city disrupts the natural water balance and directs stormwater into conventional canal drainage systems. A heat island is also produced by the city’s sealed concrete surfaces.

The concept of a sponge cityscape involves applying a variety of techniques in a cohesive manner. Rainwater would not be released into the canal but rather kept in the city for a significant portion of it. Rainfall-runoff would be lessened by the creation of numerous tiny retention storage areas on building roof surfaces and streetscapes. Through vegetation evaporation, it also contributes to the improvement of the urban microclimate.

One common strategy to limit runoff water is to retain precipitation both above and below ground. Rainwater harvesting, the installation of bioswale areas in public spaces, and the protection of the city’s surviving lakes and ponds are some other strategies. Unsealing and reviving is the way to uncover the old natural canals or water sources which was channelized or covered by the pipe. Another method is to use materials that are permeable to water in parking lots, outdoor markets, and public plazas. 

Furthermore, to create a water park near the Moyur River area following these concepts, multifunctionality is essential. In order to function, it would be very beneficial to remove illegal encroachment and engage people. Riverbank with multiple uses: for recreation during the dry season and for water during the rainy season. In addition, the water park would improve interaction between the locals and the surrounding environment. Furthermore, extensive and intense greenery cultivation would serve as an evaporating element to improve the climate.

Conclusion: The thesis serves as a model for water-responsive landscape design solutions in urban areas vulnerable to flooding and waterlogging. The project presents an eco-friendly landscape design in response to urban water-related disasters through the concept of the “sponge city.”

[This Academic Project has been published with text submitted by the student]