When building a new well, we prefer to drill boreholes. Boreholes reach down below the water table to aquifers – layers of water-bearing rock where water can be extracted. Drilling far away from surface pollutants means there is little risk of contamination and obviously the water doesn’t dry up depending on the seasons. When the boreholes are drilled, there’s little need for maintenance beyond a local mechanic servicing the hand pump – which we make sure gets done!
Sometimes though, we aren’t able to drill boreholes. It may be there are no local aquifers, there are too many natural pollutants, or the area is too remote for drilling rigs to access. In these cases we need to look for other solutions.
If there is enough rainfall during rainy seasons, Rainwater Harvesting can be a good solution. Rainwater is fed from guttering off roofs and into storage where it serves as a reservoir in the dry seasons. Rainwater itself is relatively pure but it can be contaminated by industrial pollutants in the air (in these cases, we wouldn’t use Rainwater Harvesting as a solution?) or by dirt (from birds and animals) on the roofs. The latter can be guarded against by simple chlorination treatments, but someone in the villages needs to be entrusted with the responsibility of carrying out the chlorination. We have used Rainwater Harvesting twice. In both cases, it served a school, with an educated and responsible headmaster!
To get a Rainwater Harvesting project going, a suitable storage size is calculated using local rainfall information, and the usable roof area available. The storage tank is then constructed either aboveground, or in our case, it is dug out of the ground and lined with a suitable material (often concrete). The tank is then connected to the roof guttering, with a swivelling pipe so that the very first rain (carrying the initial dirt off the roof) can be kept out of the tank.
Photos from our Rainwater Harvesting Projects