CIVIL WORKS GUIDELINES FOR MICRO-HYDROPOWER IN NEPAL
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9.5 Terracing and dry stone wall
Lack of effort in looking for alternate wall types, such as
terracing and dry stone walls often rules out the development
of other techniques that are more economical and durable.
Minor landslide areas can be stabilised by constructing dry
stone terraces as can be seen in Figure 9.3. The overall slope
of such terraces should be limited to 30° (i.e. terrace width
should be twice its height). 500 mm thick dry stone walls
should be used for the vertical face of the terraces. Such dry
stone walls retain the soil behind and allow the surface water
to drain out. Constructing small catch drains on the terraces
helps to reduce soil erosion by draining the surface water. An
alternative method used to stabilise the steeper Jhankre mini-
hydro powerhouse slope is discussed in Box 9.1.
Photo 9.3 Gabion at the toe of an unstable slope
Photo 9.4 Stone masonry can provide slope stabilisation along the route of the penstock (Barpak)