At sections, where a river is narrow and shallow, the current will be faster while at sections where the river is wide and deep, the current will be slower. Explain.

Explanation

According to principle of continuity for an incompressible fluid,`A_(1)v_(1)=A_(2)v_(2)`
It means that, at sections where the area of cross section (taken normal to flow) is smaller, the velocity is higher and vice versa.