Human and animal powered water lifting devices
Practical Action
Advantages
Disadvantages
Traditional technology which can be locally
made and maintained.
Water yields of approximately 300 l/min for
lifts of 0.5 m
Limited to lifts of less than 0.5m
Not very efficient (20-50%), lots of backflow
Persian Wheel (Raha)
This device consists of an endless chain of buckets typically with an individual capacity of 8-
15 litres mounted upon a drum and submerged in water to the required depth. The drum is
connected to a toothed wheel held in a vertical plane by a long shaft usually kept below ground
level. The vertical toothed wheel is geared with a large toothed horizontal wheel connected to a
horizontal beam. This beam is yoked to a pair of animals. The animals move in a circle to turn
the drum and raise the water. Water is released when the bucket reaches the top.
The average discharge rate from a Persian wheel is about 160-170 litres/min from a depth of 9m
with one pair of bullocks. The Persian wheel can be used to raise water from a depth of up to 20
m but its efficiency is reduced at depths below 7.5 metres.
Figure 6: Animal Driven Persian Wheel
Source: Water Pumping Devices
A variety of all-metal improved Persian wheels have been built. Their smaller diameter reduces the
extra height the water needs to be lifted before it is tipped out of the containers, and also reduces
the well diameter that is necessary.
Advantages
Disadvantages
A relatively inexpensive traditional technology
which can be locally made and maintained.
Easy to operate
Lifts water up to 20 m but most efficient at
depths of less than 7.5 m. Water yields of
approximately 160-170 l/min for lifts of 9 m
The design means that water is raised above
the point of discharge before falling into the
collection channel.
Animals need to be maintained all year even
when irrigation is not necessary.
Medium efficiency (40-70%)
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