Spurs and dykes
Practical Action
The cost of creating the spurs and dykes can be kept low through community participation.
Ideally land is contributed to the project and the labour contribution will vary from between 10
and 100% depending on the type of activity and the need for specialist contributions. Often the
majority of materials are also donated to the project.
In the example of the spur constructed at Chitwan specialists were used in the design stage of
and engineering drawings produced from which the project requirements in terms of material
and labour could be determined. The spur construction is shown in Figure 5. The size and shape
will change depending on the particular circumstances of each location.
Figure 4: Cross section of a spur design in Chitwan showing substantial groundwork
Illustration: Practical Action Nepal.
An essential element to constructing a spur is the incorporation of the apron which ensures that
the structure is not undermined by the current. The design should ensure that the spur is rooted
into the bed of the river and not resting on the river bed (as in the case in figure 4) where the
structure is likely be rolled away during heavy flooding.
In general the communities in Nepal
have shown a great deal of motivation
to carry out mitigation work and have
requesting more structural work to be
done.
In Meghauli (Chitwan) one spur of
9m ×6m ×7m was completed before
the monsoon. The community was
particularly highly motivated as their
land was threatened by two major
rivers. They contributed 400 days of
work (40 people a day for ten days on
average).
Groundwork is done on the riverbed
to build the apron. Gabions can then
be placed in position to provide
protection for the main structure of
the spur. Undermining of the apron
may still occur but this will not result
in any structural damage as the
apron will flop down.
Figure 6: An example of a spur that has not been
installed with groundwork or an apron and consequently
is likely to be washed away during heavy flooding.
Photo: Practical Action Nepal.
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