Slide 1

ALIGNMENT OF CANAL AND HYDRAULIC PARTICULARSPresentation by: G. Krishna Reddy S. Gopinath Reddy Md. Fasi Canals Canals are open channels that transport water from a source to distribution and delivery locations.

Canals may be either lined or unlined depending on earth and rock materials encountered.

If the R.L of formation of canal bed is below the R.L of ground cutting is done and vice versa.

Classificationof canals onthe basisof their functions are given below:

Irrigationcanal.Navigation canal.Power canal.Link canal.Feeder canal.

Irrigation canals These are the canals which carry water to the fields.Navigation canal These are the canals which are used to provide transport and voyage facility from one city to the other or from one country to the other. Main canal is navigation canal.Power canal The canals which are constructed to supply water with very high force to the hydro electric power station for the purpose of moving turbine to generate electric power is known as power canal.

Link canal The canal that is from river to river is known as link canal. which are constructed to transfer water to the other conveyance structurewhich contains in-sufficient quantity of water.

Feeder canal A feeder canal is constructed with the idea of feeding two or more canals. When main canal is divided into two canals then it is called as feeder canal.

Alignment of canals

irrigation canals can be aligned in any of the following three ways:

As watershed canal or ridge canal.As contour canal.As side slope canal.

Watershed canal or ridge canal The dividing ridge line between the catchment areas of two streams is called the watershed. Thus, between two major streams, there is the main watershed, which divides the drainage area of the two streams. Similarly , between a main stream and any of its tributary, there are subsidary watersheds dividing the drainage between the two streams on either side. It is suitable for plain areas, where slopes are relatively flat and uniform. The canal which is aligned along any natural watershed is called watershed canal. This type alignment ensures gravity irrigation on both sides of the canal. However , the main canal has to take off from the river and it must mount the watershed in as short a distance as possible . Once the canal has reached the watershed , it is generally kept on the watershed ,except where

Localities are settled on the watershed.Where the canal is looping and not running straight . If the watershed passing through villages or towns, the canal may have to leave the watershed for some distance. contour canals This is widely used method for alignment of canals. The ridge line method is not found economical in hill areas. In hills, the river flows in the valley well below the watershed. Infact, the ridge line may be hundreds of meters above the river, so it is impossible to take the canal on top of such a higher ridge line. In such conditions contour canals are usually constructed. Contour channels follow a contour except for giving the required longitudinal slope to the canal.

A contour canal irrigates only on one side because the area on the other side is higher. As the drainage flow is always at right angles to the ground contour. Such a channel would definitely have to cross natural drains and streams, necessiating construction of cross drainage structures.

Side slope canal It is a canal which is aligned at right angles to the contours. Since such canal runs parallel to the natural drainage flow, it usually doesnt intercept drainage channels. Thus, avoiding the construction of cross drainage structures. Hydraulic particulars

Approved alignment plan showing all structures along the alignment Longitudinal section of the canal preferably to the scale H 1cm:100m & V 1cm:10m Cut off diagram for the project / canal Design discharge Rugosity coefficient Full supply depth Width of land acquired Following statements in the prescribed form for each set of works viz. sluices, railway bridges, road bridges, foot bridges, regulator, C.D. works and drops etc.

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