Harvesting rainwater works well if you have access to buildings, which are roofed with iron sheets. The rainwater remains clean and can be led from the roofs to special water tanks. In the tanks, the water can be stored for months. But it is not easy to construct sustainable water tanks in concrete, without using too much cement and rebar, which are expensive materials in Tanzania. In 2003, IDC learned a good construction method by collaborating with technicians from Kenya. At IDC's learning centre there are two ten-year-old tanks of different sizes – still completely intact!
IDC has over the years built a number of rainwater tanks of this type, both smaller tanks (5-10 m3) for individual households and larger tanks (25-60 m3) for schools and healthcare clinics. The tank on the photo (above) was built in 2008 at a health clinic in one of the neighbouring villages. Now, IDC has a solid reputation for being experts in rainwater tank construction!
The mason students at IDC's vocational school learn the technique in the second year. When IDC get a contract for building a new tank, they will be part of the work-team and thus get the opportunity to practice under the supervision of skilled foremen.
Click on "How to build" on the left, to see the different steps in IDC's construction method.