8.6.4. Cross-Section of Irrigation Channels An irrigation channel may be in cutting or in filling or in partly cutting and partly filling. When the ground level is higher than the full supply level of the channel, the channel is said to be in cutting [Fig. 8.8 (a)]. If the channel bed is at or higher than the surrounding ground level, the channel is in filling, [Fig. 8.8(b)]. When the ground level is in between the supply level and the bed level of the channel, the channel is partly in cutting and partly in filling [Fig. 8.8 (c)]. A channel section partly in cutting and partly in filling results in balanced earthwork and is preferred. Various components of cross-section of an irrigation channel have been discussed in the following paragraphs.
306 IRRIGATION AND WATER RESOURCES ENGINEERING
GL
(a) Channel in cutting
Service road
Dowla
Counter
berm
(b) Channel in filling
(c) Channel partly in cutting and partly in filling
Fig. 8.8 Typical cross-sections of irrigation channels
