42 CIVIL WORKS GUIDELINES FOR MICRO-HYDROPOWER IN NEPAL
Box 4.2 The experience with ferrocement in Nepal
Ferrocement pilot projects have been promoted by the
Andhi Khola Irrigation Project (AKIP) and the International
Labour Organisation (ILO). Ferrocement structures are
made of thin cement sand mortar (1:2 to 1:3) with thin
steel mesh as reinforcement. ILO has used ferrocement
for lining irrigation canals in the Sindhuli Flood Rehabilita-
tion Project.
The ILO ferrocement canal cost was US$ 31 per linear
metre and the cement masonry design of similar ca-
pacity was US$ 28 (1989 prices). The ILO justifies the
additional cost by attributing it to better durability and
little maintenance which ferrocement canals require.
Other advantages are smooth finishing which reduces
head losses, resistance to abrasion, and very low seep-
age losses.
The ferrocement flume used in AKIP (designed by BPC
Hydroconsult) is shown in Photograph 4.6 and Figure
4.1. Galvanised sheets with intermediate steel frames
were used for the formwork. Multiple layers of 10 mm to
15 mm thick, 1:3 cement sand mortar were placed on
the formwork. The final inside layer (i.e. water retaining
surface) was prepared using a mix of 1:2 cement sand
mortar. Galvanised thin wire mesh (also known as
chicken wire mesh) was placed between each layer as
reinforcement.
The Andhi Khola ferrocement flume has been function-
ing well since its commissioning in 1993. This design
was more economical than the conventional stone ma-
sonry in cement mortar canal with drop structures. How-
ever, it should be noted that the construction of
ferrocement canals requires skilled and well trained
manpower (masons) to achieve the required quality of
work and therefore may only be justified where a very
long canal is to be installed in poor soils. Furthermore, if
skilled labour is expensive, ferrocement canals may cost
more than the conventional design, as in the case of
Sindhuli Flood Rehabilitation Project.
Photo 4.8 Andhi Khola Project ferrocement flume
Figure 4.1 Andhi Khola Project ferrocement flume