Rain Bellows is an architectural solution utilizing building facades to clean and store stormwater for reuse. Inspired by the form and function of the Ice Plant, Mesembryanthemum crystallinum, Rain Bellows showcases its storage capacity by expanding the exterior skin of a building until water is needed.

In addition to our biomimicry design we showcase our methodology as part of our competition entry. This five step method allows design through biomimicry to become a more approachable design strategy. Breaking down the steps into a simple sequence helps translate strategies from nature into design ideas.

Our challenge starts with water. Every organism uses water in a different way. Through a reductive process of looking for Champion species that excel at water conservation, we identified the Ice Plant. This plant is endemic to arid parts of southern Africa and not native to the US Pacific Northwest. However, it has evolved distinctive water strategies to address long dry periods, similar to Northwest summers.

To address polluted runoff problems, the City of Seattle passed a resolution requiring green infrastructure to manage 700 million gallons of runoff by 2025. Green infrastructure is incredibly important, but it is not enough. In areas where there are distinct wet and dry periods, the constraints of storing large volumes of water in cisterns can be costly, requiring a larger building footprint or site area.

Our basis for design is a highly-sustainable commercial building in Seattle, Washington. The building achieves the requirements of the Living Building Challenge, with 75% reduction of potable water as well as reuse of at least half of the stormwater that falls on the site. The design of this Living Building revealed an opportunity to reduce the use of potable water in an urban environment.

Once stormwater falls on a surface it is categorized by the potential for contamination by pollutants. Roof surfaces that are not accessible can divert water to cisterns for reuse with simple filtration provisions. Water that falls on road surfaces requires higher levels of filtration with no reuse allowed to protect human health. In the middle of these two extremes, roof decks present a unique condition of minimal risk for contamination, but due to the possibility of it, direct reuse of this water is prohibited. Our biomimicry-inspired design targets this mid-level contaminated water.

As the Ice Plant stores water within specialized cells on its surface to be used later, so can a building by expanding the function of the building envelope. The goal was to integrate stormwater cleaning, storage, and reuse into the building façade using essential building materials via methodology that could be replicated on future projects. The unique cellular structure of the Ice Plant provides the inspiration of filtering, storing, and reusing water through the specialized cellular layers of the plant. By designing a building to mimic the Ice Plant’s function, we optimize the use of water that falls on a site by increasing the functionality of the building membrane.

Rain Bellows applies nature’s strategies at a building scale.