Medical &Health

Climate Conscious Architecture: Bangladesh’s Rainwater-harvesting Hospital Wins International Award

The RIBA International Prize 2021 is given to a hospital in Bangladesh’s Satkhira district for being the world’s greatest new structure. The Friendship hospital is a paradigm of climate-conscious architecture created with the lowest minimum of resources. It triumphed over competition from a David Chipperfield-designed museum in Berlin and a Wilkinson Eyre-designed cycling and footbridge in Denmark.

The RIBA International Prize 2021 winner drew inspiration from water. The canal winds across the property, gathering important rainfall and aiding in the cooling of the adjacent courtyards during the scorching summer months. It acts as a hurdle between the inpatient and outpatient sections, segregating the two halves of the site without the need for a dividing wall.

Conceptual and Designing Aspects

When Cyclone Sidr struck the nation in 2007, causing an ever-changing terrain due to increasing water levels, the narrative for this corner of the globe shifted dramatically. Due to constant climate change, seawater has infiltrated the interior, causing all adjacent agricultural lands to be turned into shrimp production ponds.

The land around the Friendship hospital was once covered with grain fields. The surrounding settlement was also precarious, consisting mostly of low-rise buildings and thatch homes. Recognizing the limits, the Bangladeshi architect designed a somewhat linear plan with interconnecting courtyards and covered pathways to divide the inpatient and outpatient zones. When it came to establishing access control between these locations, he created a rainwater collection canal that crisscrossed the site’s center.

This feature operates in a variety of ways. On a functional level, the captured water assists in microclimate cooling and provides a vital resource in a location where salty water is useless for the majority of functions. On an aesthetic level, the property’s constant presence of water animates the inside environment and imparts a feeling of visual continuity.

A Project of Collaboration

“Water pervades this space,” explains architect Kashef Chowdhury, head of Urbana, the Dhaka-based firm that designed the building. “However, it is not necessarily of the beneficial kind.” Rising sea levels as a result of the climate catastrophe have changed the surrounding landscape of grain fields into shrimp fishery, while the groundwater has become too salty for most uses.

Locals make every effort to gather and save every last drop of freshwater during the rainy season. Chowdhury has built the building as a rainwater harvesting machine, with every roof and courtyard surface emptying into the central canal, which connects to two storage tanks at the site’s ends.

It is the organization’s first “land hospital,” since Chowdhury previously assisted in converting many boats into floating hospitals to serve rural villages in the delta area. Built on the lowest budget of just under $2 million, its first permanent structure serves as a lifeline for thousands of people in a region devastated by a destructive hurricane in 2007.

A Mesmerizing Building with Unique Perks

The Grand Jury for the coveted prize, which included prominent people such as Es Devlin, Jeanne Gang, Rossana Hu, and Gustavo Strabo, as well as Decq, thought it pleasant to see a hospital with such a kind and natural touch. “The Friendship Hospital is particularly timely at this point in history since it tackles the global problem of uneven access to healthcare,” an official press statement noted, adding that the winning project was also named the world’s greatest new building.

“It is an example of how a beautiful building can be accomplished via strong design even when dealing with a limited budget and constrained contextual conditions. This hospital is a celebration of a human-centered structure.”

Architect Kashef Chowdhary, whose practice is rooted in history and places a premium on climate, materials, and context, discusses winning the award, “In a sublimely significant moment, the RIBA and the jurors have identified a project from the global periphery to elevate to the center of architectural discourse and become the subject of one of the most prestigious global awards.” I am pleased that this may motivate more of us to commit to an architecture of care for mankind and the environment, not in spite of, but precisely because of, resource and means constraints, in order to jointly address the global urges we confront; today.”

Cultural Acceptability

Rainwater collecting is a widely acknowledged method of augmenting freshwater supplies in southern Bangladesh. While rainwater collected from ground catchments has a low bacteriological quality, rainwater collected from well-maintained rooftop catchment systems fitted with tight storages and taps is typically good for consumption and often satisfies WHO drinking water criteria. This water is of greater quality than that available in the majority of the world’s conventional water sources.

Rooftop rainwater collection may produce excellent quality water that is safe to drink if the rooftop is clean, impermeable, constructed of non-toxic materials, and is positioned away from overhanging trees.


Rainwater collection is one of the most promising options for meeting rising water shortages and demand. The strain on water resources, the increasing environmental effect of huge projects, and worsening water quality all limit the capacity of conventional sources to supply the demand for freshwater. Rainwater collection enables the supplementation of water sources while also promoting self-sufficiency and sustainability.


Rainwater harvesting effectiveness is determined by the materials used, the design and construction, the maintenance, and the overall quantity of rainfall. The runoff coefficient, which is the proportion of precipitation that occurs as runoff, is a frequently cited efficiency measure of 0.8. By contrast, when cement tiles are utilized as a roofing material, the year-round runoff coefficient is around 75%, but clay tiles often collect less than 50%, depending on the harvesting mechanism employed. Plastic and metal sheets perform the best, with an efficiency of 80–90%. A well-designed and meticulously built gutter system are also critical for the proper functioning of a rainwater harvesting system. If the gutter and down-pipe system are installed and maintained correctly, 90% or more of the rainwater collected on the roof will be discharged to the storage tank.

Source: United News of Bangladesh