Correct Answer - Option 4 : Neither the water level in the distributary nor the water level in the water course
Explanation:
Canal Outlets or Module:
(i) A canal outlet is a small structure built at the head of the water course so as to connect it with a minor or a distributary channel.
(ii) It is also called sluice.
Types of Canal Oulets:
Canal outlet can be classified mainly into three classes:
(i) Non modular outlets:
- Non modular outlets are those outlets whose discharge depends on the difference of water levels (i.e. head) between the distributary and the water course.
- Such an outlet is controlled by a shutter at its upstream end.
- Non modular outlets are very suitable for low head condition.
- Example: Submerged pipe outlets and masonary sluices
(ii) Semi-modular outlets:
- Semi modular outlets are those outlets whose discharge depends only on the water level in the distributary and is unaffected by the water level in the water course provided that a minimum working head required for working is available.
- Example: Pipe outlet, Venturi flume
(iii) Modular outlets:
- Modular outlets are those whose discharge is independent of the difference of water levels in the distributary and the water course.
- These are called Rigid modules.
- Example: Gibb's module
