Question

The best alignment for a canal is when it is aligned along:

• A. Valley line
• B. Stream line
• C. Contour line
• D. Ridge line.

Answer 1

The correct option is D Ridge line.

1. The irrigation water inflow type should reach the field by gravity to accomplish water requirement irrigation canal is always aligned in such a way that the water gets proper command over the whole irrigable area. If the canal flows a watershed or ridge of the drainage area it will get the necessary gravity flow. The watershed or ridge is a dividing line between two drainage areas. Thus, the canal which runs over the ridgeline gets a command area on both sides of the ridge.
2. Another advantage of keeping a canal on the ridge is that the crossing of drains and canals is completely avoided.

3. $\text{Other definitions}$

4. $\text{Contour lines:}$ A contour line may be defined as an imaginary line passing through points of equal elevation on the earth’s surface.
5. $\text{Stream line:}$ A streamline is a curve such that at each point of it, the tangent direction gives the direction of the instantaneous local velocity vector.
6. $\text{Valley:}$ A valley is an elongated depression in the landscape that is formed by the action of water (V-shaped) or carved out by glacier (V-shaped).
7. $\text{Ridge:}$ A ridge is a landform feature characterized by a continuous elevational crest with sloping sides.