Question

Which of the following combination is incorrect?

(a) Silt removal – Silt ejectors and silt escapes

(b) Aquatic weed control – Mechanical removal of plants

(c) Breach due to piping – provision of a sand core in the bank

(d) Breaches in a big canal – Dumping huge quantity of earth

The question was posed to me during an internship interview.

The origin of the question is Irrigation Canal topic in portion Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

Right answer is (d) Breaches in a big canal – Dumping huge quantity of earth

To explain: This process cannot be adopted for a bigger canal. The outflow from the canal breach will be large and all the soil dumped for closing the breach may be washed off. For bigger canals, the outflow is reduced first followed by cutting the sides of the gap and then driving the double pile in the opening of the breach.