Three Factors Controlling River Flow

River velocity is governed by three primary physical factors:

1. Gradient (Slope): Steeper gradient → faster flow (gravity-driven).
2. Channel Shape: Narrow, deep channels accelerate flow; wide, shallow ones slow it (hydraulic radius effect).
3. Discharge (Volume): Greater water volume → higher velocity (more mass, more momentum).

These interact: a steep, narrow, high-discharge river flows fastest.