Rainwater Harvesting for Reconstruction
Practical Action
Rainwater Quality & Health
There are two main issues when looking at the quality and health aspects of domestic RWH;
firstly, there is the issue of bacteriological water quality. Rainwater can become contaminated by
faeces entering the tank from the catchment area. It is advised that the catchment surface always
be kept clean. Rainwater tanks should be designed to protect the water from contamination by
leaves, dust, insects, vermin, and other industrial or agricultural pollutants.
Tanks should be sited away from trees, with good-fitting lids and kept in good condition.
Incoming water should be filtered or screened, or allowed to settle to take out foreign matter (as
described in a previous section). Water which is relatively clean on entry to the tank will usually
improve in quality if allowed to sit for some time inside the tank. Bacteria entering the tank will
die off rapidly if the water is clean.
Algae will grow inside a tank if sufficient sunlight is available for photosynthesis. Keeping a tank
dark and sited in a shady spot will prevent algae growth and also keep the water cool. The area
surrounding a RWH should be kept in good sanitary condition, fenced off to prevent animals
fouling the area or children playing around the tank. Any pools of water gathering around the tank
should be drained.
Secondly, there is a need to prevent insect
vectors from breeding inside the tank. In areas
where malaria is present, mosquito breeding in
the storage tank can cause a major problem. All
tanks should be sealed to prevent insects from
entering. Mosquito proof screens should be fitted
to all openings. Some practitioners recommend
the use of 1 to 2 teaspoons of household
kerosene in a tank of water which provides a film
to prevent mosquitoes settling on the water.
Figure 8: Covered water storage in Uganda
Photo: Practical Action
Domestic RWH in a PCR Context
How does RWH relate to the three stages of the reconstruction process and the principles of PCR?
Rainwater harvesting cannot be relied upon in all emergency situations, but in cases where
rainfall is present every effort should be made to capture it, as it provides a clean, safe source at
low cost (UNHCR, 2007). Methods in an emergency stage are usually basic, most commonly
consisting of plastic sheeting directing water to buckets; the resources and time required to
implement more advanced systems are generally not available until later on in the reconstruction
process.
Transitional shelters afford more opportunity to capture rainfall, generally being occupied for
longer periods. The construction of simple pots with sheeting as a catchment is a mobile solution
that doesn’t require much capital or labour investment. However, the ability to capture fresh
rainwater and to manage its use over periods of time can be developed to a much greater extent in
the permanent housing stage of reconstruction; a key aim of PCR is to decentralise infrastructure
and to give people more independence over controlling their water supply.
Individual housing units that are permanent constructions have much more opportunity to invest
in more complex harvest systems, with more time to experience the benefits and to understand
and adapt to changing rainfall patterns. The greater space that comes with individual dwellings
allows for the construction of tanks or cisterns, and guttering can be added to well-constructed
permanent houses. The construction of harvest systems has potential to open up local markets,
improving living conditions and livelihoods at the same time, whilst also reducing vulnerability to
potential future droughts.
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