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3.12 Bamboo Pipe Water Supply System
In some villages in the hills of Nepal, drinking water is supplied to
consumers through a bamboo piping system. In Barbotey Village, in the Ilam
District of Nepal, for example, water is supplied to two households (12
people) from a common source. A longitudinally cut bamboo tube,
semi-circular in cross-section, serves as an intake. Water, drawn from the
source, flow along about 100 m of open channel bamboo piping to a bamboo
tap. Water flows by gravity down a 1% slope that follows the ground
profile. The bamboo pipes, supports and ancillary plumbing fixtures are
made from bamboo stems cut from the nearby forests.
The raw bamboo is cut in half to form a semi-circular pipe, and laid on
the top of bamboo supports that carry the pipe down the slope to the
consumers. At each change in direction (i.e., at the bends), the pipe is
braced and supported by bamboo itself. At each socket joint, two bamboo
lengths overlap and are again supported by bamboo bracing. At the bamboo
tap, a bamboo inlet is inserted from the top and water is withdrawn hole
at the bottom. A small HDPE pipe is also used in building the tap. This
system is completely based on local technology using local materials.
Extent of Use
Bamboo conveyance systems are used throughout the hilly areas of the
eastern region of Nepal.
Operation and Maintenance
Because bamboo decays as a result of its exposure to the weather and the
scouring effect of the flowing water, all of the bamboo components have to
be replaced each year. Thus, the annual operation and maintenance costs
are the same as the capital cost, about $4.60 per year.
At present, two households have been operating and maintaining the
system. They frequently visit the line to remove debris so that water
flows smoothly. Surplus water is used for kitchen garden watering
purposes. More than 50% of the water entering the system is lost due to
leakage during the passage of the water from the source to the tap.
Level of Involvement
These distribution schemes may be implemented at the local community
level, by the local users themselves. New techniques to improve the system
have not been implemented, and the users are waiting for this scheme to be
replaced by a piped water system. Nevertheless, there are some measures
which could be considered fin order to improve the bamboo distribution
system and the government could promote this technology in other areas
where bamboo is commonly available.
The cost of the scheme is very low, as it only uses local materials.
Total cost is about $4.60, and is incurred annually in the replacement of
Effectiveness of the Technology
At present, the system provides 0.20 l per person of drinking water in
the wet season. This volume diminishes to 10% of the wet season volume
during the dry season. The system eliminated the need for the women of the
households served to walk long distances to fetch water.
This technology is suitable in areas with a good natural source of water
nearby, a steep topography, and a ready source of natural piping
This technology is simple and uses local materials. Therefore, it is
very cheap and can be implemented at the local level without skilled
labour or specialised materials and equipment.
Since the bamboo piping is simply placed on top of the framework that
supports the pipeline, high winds or broken branches can displace the
piping and cause the system to break down. Further, because the pipeline
is open, the chances of dirt, debris and tree leaves falling into, and
contaminating, the water are extremely high. This potential for
contamination requires that users screen and boil the water before they
use it for drinking purposes.
Further Development of the Technology
This technology could be improved through the development of means to
ensure that (i) the bamboo pipe is free from debris and contaminants, (ii)
there is a continuous flow of water to minimize the rate of decay of the
bamboo (bamboo left without water for more than 60 days decays rapidly),
and (iii) there is provision for chlorination (at a rate of 10 mg/l
chlorine) to improve water quality as well as preserve the bamboo from
decay. Some improvements in this technology which have already been
identified include the use of a fully enclosed bamboo pipe and plastic
pipe joints between tube segments to control water loss due to evaporation
and spillage. The use of fully enclosed bamboo tubes is impeded somewhat
by the internodes which grow naturally across the bamboo stem at intervals
of about 1 m. These must be removed by drilling, adding a degree of
complexity to the technology (the drilling can be accomplished using an
hand auger attached to a steel bar, manually inserted into the bamboo tube
from both the ends). Also joining the bamboo stems with polyethylene pipe
of an appropriate size can control leakage through the joints. Bamboo
pipes also can be reinforced with 3 mm diameter galvanized wire, which can
also be used to anchor the pipeline to the supporting structures. In some
situations, the pipe can be laid underground, but problems may arise due
to the presence of fungi and termites. Applications of insecticides and
anti-fungal agents can be applied to the trenches to control these pests,
but at the increased risk of contamination of the supply.
Amar Neku, Engineer, District Water Supply Office, Ilam
District, Mechi Zone, Nepal.