Module 4 - Construction of a gravity fed system

Fig.24: Crossing a gully or a river using suspended pipe (length above 10 m).
Table 13: Pipe diameter and maximum length with a cable of 8mm diameter.
Diameter of
PE/PVC pipe
20 mm 32 mm 40 mm 50 mm 63 mm
Diameter of GI pipe 1” 1” ½ 2” 2” ½ 3”
Maximum length 170 m 100 m 70 m 50 m 40 m
*Crossing a shallow river:
When the river is not very deep, the pipe can pass below the river. In this case, we install the
PE/PVC pipe inside a GI pipe located in the riverbed as illustrated in figure 25. To prevent
the pipe to be washed away by the water stream, you must build a low but large wall of stone
at a distance of 1-2m downstream of the pipe, to decrease the water speed at this place.
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