Question

Lock and dams constructions for creation of a series of slack-water pools along a river for promoting its navigability is adopted only when ________________________

(a) the river is perennial

(b) the river carries heavy sediment load

(c) the available water in the river is quite less

(d) the available water in the river is quite large

I have been asked this question during an internship interview.

I'm obligated to ask this question of Navigable Waterways Requirements in chapter River Navigation & Tank Irrigation of Irrigation Engineering

Answer 1

The correct option is (c) the available water in the river is quite less

For explanation I would say: This arrangement is generally adopted where existing site conditions are not favorable for adopting open channel methods. The water is required for lockage, sanitary releases, evaporation, percolation, etc and the requirement is much less than that of open channel procedures. Hence, it is adopted when the water available is less.