Rainwater harvesting
Prone to attack from weather
Failure can be dangerous
Practical Action
Contamination of the cistern from
groundwater is more common
Tree roots can damage the structure
There is danger to children and small
animals if the cistern is left uncovered
Flotation of the cistern may occur if
groundwater level is high and the
cistern is empty.
Heavy vehicles driving over a cistern
can cause damage
Figure 4a: An owner-built brick tank in Sri
Lanka
Figure 4b: A corrugated iron RWH tank in
Uganda
Much work has been carried out to develop the ideal domestic RWH tank. The photographs
(Figures 4-6) illustrate the variety of tanks that have been built in different parts of the world.
Figure 5 : Ferrocement tank in Ruganzu Village,
Tanzania. Photo credit: DTU
Figure 6 : Small jars used in Cambodia
as part of a multi-sourced water supply.
Photo Credit: DTU
First-flush systems
Debris, dirt, dust and droppings will collect on the roof of a building or other collection area.
When the first rains arrive, this unwanted matter will be washed into the tank. This will cause
contamination of the water and the
quality will be reduced. Many RWH
systems therefore incorporate a system
for diverting this ‘first flush’ water so
that it does not enter the storage tank.
The simpler ideas are based on a
manually operated arrangement whereby
the inlet pipe is moved away from the
5
Figure 7a: Tipping gutter mechanism