Civil Engineering - Irrigation - Discussion

What is stream line?

Contour canal is only used in hilly areas.

Why the contour canal is avoided?

Contour line is used in hilly ares. Well explained & Thanks @Omkar.

Why contour line is not an answer?

Watershed canal or ridge canal:

* The dividing ridge line between the catchment areas of two streams (drains) is called the watershed or ridge canal.

* Thus between two major streams, there is the main watershed (ridge line), which divides the drainage area of the two streams, as shown in figure below. Similarly, between a main stream and any of its tributary, there are subsidiary watersheds (ridge lines), dividing the drainage between the two streams on either side.

* The canal which is aligned along any natural watershed (ridge line) is called a watershed canal, or a ridge canal. Aligning a canal (main canal or branch canal or distributary) on the ridge ensures gravity irrigation on both sides of the canal.

* Since the drainage flows away from the ridge, no drainage can cross a canal aligned on the ridge. Thus, a canal aligned on the watershed saves the cost of construction of cross-drainage works.

Canal at the ridge is impossible because dams always at the valley.

Why it is align on ridge?

What is ridge line?

But canal align along the contour can irrigate only one side of the canal.