How design influenced Africa’s only waterbank school

Images by David Turnbull, Aggrey Maganga

The Uaso Nyiro Waterbank School in Laikipia, an area with an annual rainfall of 600mm, boasts a 600-square-metre roof catchment area that can harvest, store and filter nearly 400 000 litres of rain water annually for use by the school and the neighbouring community.

Implemented by the Zeitz Foundation in partnership with PITCHAfrica, the Waterbank School is a low-cost building designed to be a water-harvester as well as a primary education centre. David Turnbull, PITCHAfrica’s design director, told Ogojiii that they were originally researching the idea of building a stadium that would harvest water, but the construction cost was prohibitive.

“We wanted the smaller building to be replicable, and something that with a modest amount of funding any community based organisation could build.”

According to Turnbull, the fundamental principles that define the Waterbank School, and the more recent Waterbank Campus at the Endana Secondary School, are simple. First, all the buildings have to provide the largest catchment surface, typically a roof that is affordable.

Second, build the biggest reservoir or tank, preferably in the centre of the building and ideally underground. Third, provide pathways for the collected water so that as much rainwater can find its way into the tank without evaporating.

Fourth, provide a secondary tank on the roof of the building, connected to the large reservoir, that can hold a day’s supply of water, which can then be filtered to that it is safe to drink.

“In the Central Highlands of Kenya that can mean that your annual water yield is 350 000 litres from a simple building. In the Niger Delta of Nigeria, for example, this tank would have to be considerably bigger, because the annual rainfall is three times what the Waterbank School experiences. But we think that the goal of providing 100 000 – 150 000 liters of water storage capacity is good,” Turnbull says.