The canal water has reached near the fields to be irrigated, it has to be transferred to the watercourses. At the junction of the watercourse and the distributary, an outlet is provided. It is a masonry structure through which water is admitted from the distributary into a course. It also acts as a discharge measuring device. The discharge though an outlet is less than 0.085 m3/s (3). It plays a vital role in the warabandi system of siting water. Thus, an outlet is like a head regulator for the watercourse.
The main objective of providing an outlet is to provide ample supply of water to the whenever needed. If the total available supply is insufficient, the outlets must be such suitable distribution can be ensured. The efficiency of an irrigation system depends on proper functioning of canal outlets which should satisfy the following requirements (3):
The outlets must be strong and simple with no moving parts which would require periodic attention and maintenance.
The outlets should be temper-proof and if there is any interference in the functioning of the outlet, it should be easily detectable.
OF CROSS-DRAINAGE STRUCTURES
Aligning a canal on the watershed of an area is necessary so that water from the canal can by gravity to fields on both sides of the canal. However, a canal taking off from a river at has to necessarily cross some streams or drainages (such as a,b,c, and d in the before it can mount the watershed of the area at B. In order to carry canal is on the waters B, usually no cross-drainage structure is required except in situations when the canal leave a looping watershed (such as DEF in figure 11.1) for a short distance between D and may cross tributaries (as ate and f). Cross-drainage structures are constructed to negotiate aligned channel over, below, or at the same level of a stream .