More than enough rainwater falls in Africa every year, yet millions of people don't have enough to drink. The bigger problem is that water is not efficiently captured, filtered, and stored.
For Jane Harrison and David Turnbull, two British architects, this disconnect sounded like an opportunity. It inspired the duo to design a series of buildings with rainwater-harvesting at their heart.
The Uaso Nyiro Primary School, located in the Kenya's semi-arid central highlands, has just been named one of the two "greenest schools on Earth" by the U.S. Green Building Council (the other one is in Hong Kong). And it's not too hard to see why. The sustainably built school collects all of its own water. Importantly, it is also cheap (no more expensive than normal, similarly sized facilities), uses all local materials, and is designed to be replicated.
The region gets an average of two feet of rainfall a year, Harrison says. The school collects about 350,000 liters a year, using a big storage tank underneath a central courtyard. Water falls off its roofs (about 6,500 square feet in all) into the yard, where it goes through a clay-based filtration system (it's a lot like the water filter system we covered here). The clay material is embedded with sawdust, and fired, giving it a micro-porosity. It's then coated with a thin silver solution that acts like an antibiotic.
The water the school collects is enough to cater to the students and to irrigate a series of vegetable gardens in the back. Another interesting feature is a tall enclosure wall that circles the whole school. It not only keeps out unwanted humans and animals (including elephants), it also produces a micro-climate "that allows the school to work as a kind of indoor-outdoor environment," Harrison says.
See more about Uaso Nyiro here:
Aside from being an attractive place in its own right (attendance is up since it went up), Harrison and Turnbull also see the school as a proving ground. They hope it will help educate others about the possibilities of rainwater, and make people think twice before digging another well in the ground.
"The problem of water is a cultural issue," Harrison says. "It's not just something that can be solved just by producing a tap, even if you could do that. It's something that needs to be integrated very actively into the community, and the purpose for doing this within a school is that children are exposed to these principles. It's a way of sharing the information beyond the school."
Pitch Africa, the architects' Princeton-based practice, is now constructing several other rainwater harvesting buildings, including a nearby dormitory and canteen, and, most impressively, a 1,500-seat soccer stadium. The Kenya project will also house Samuel Eto'o's soccer academy, and have volleyball facilities aimed at girls. In addition, Pitch is also distributing rain-harvesting kits made of re-purposed parachutes, so ordinary people can collect water from their own dwellings.
The architects say all of their projects have the same overarching goal. "The principle with all these structures are the same. It's to show you can use building structures to harvest high volumes of water, and use that to catalyze environmentally intelligent and community-integrated development programs," Harrison says.