Rainwater Harvesting for Reconstruction
Practical Action
Storage Facility
The storage facility is usually the most expensive part of the RWH system, requiring the most
construction and capital input. There are many types of storage, such as small clay jars or
buckets, but larger vessels can generally be classified into tanks (above ground) and cisterns
(below ground).
Table 1 below describes some of the advantages and disadvantages of tanks and cisterns.
Tanks
Pros:
- Above ground structure allows easy
inspection for leakages.
- Easy manufacture from a wide variety of
materials.
- Simple water extraction through gravity,
and natural water pressure.
Cisterns
Pros:
- Generally cheaper, lower material
requirements.
- Less vulnerable to water loss.
- Lower requirement for space above ground.
- Unobtrusive.
Cons:
- Generally more expensive.
- Requires space above ground.
- Can be damaged more easily.
Table 1: Tank & Cistern Comparison
Cons:
- Water extraction often requires pumping,
- Leaks are more difficult to detect when
they do occur.
The choice of solution will normally depend on the following considerations in a PCR context:
Space availability
Materials & skills available locally – does a market exist or can one be created?
Local traditions for water storage
Cost of purchase/construction – investment vs. payback.
Ground conditions
Use of RWH – whether the system will provide total or partial water supply
Sizing of the solution must also be considered, based either on a demand or supply based
approach. Details of this are covered in the original technical brief. Additionally, further
information is available from the DTU here.
Basic Solutions
In situations where local resources are limited, and the population may not be able to afford
materials to construct advanced gutters or storage facilities, an innovative approach is often
required: a common material obtained by transient populations is plastic sheeting (Burt, M. and
Keiru, B. 2009), which can be used to divert rainwater into buckets or pots. The sheeting is
commonly used for shelter protection as well, providing a transportable, adaptable and ultra-low
cost solution. An example is shown below:
More information on ultra-low cost rainwater harvesting
techniques is available from the WEDC published paper
Innovative rainwater harvesting techniques
for emergencies: Lessons from the field.
Figure 7: Basic RWH technqiue
Source: Burt, M. & Keiru, B. (2009)
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