At Deoprayag (Garhwal, UP) river Alaknanda mixes with the river Bhagjrathi and becomes river Ganga. Suppose Alaknanda has a width of 12 m, Bhagirathi has a width of 8 m and Ganga has a width of 16 m. Assume that the depth of water is same in the three rivers. Let the average speed of water in Alaknanda be 20 km h^-1 and in Bhagirathi be 16 km h^-1. Find
the average speed of water in the river Ganga.

Question

Philoid · Accepted Answer

Here we just need balance the flow of the three rivers.

Given, Width of Alaknanda,

Width of Bhagirathi,

Width of Ganga,

Average speed of Alaknanda,

Average speed of Bhagirathi,

Let the Average speed of Ganga be

The sum of the volume flow from Alaknanda and Bhagirathi is equal to the volume flow in Ganga.

Let the depth of the rivers be

(ANS)