What Sediment Deposits First When a River Slows Down? Graded Bedding Explained

Settling Order by Particle Size

As river velocity drops, sediments settle in a predictable sequence—largest and heaviest first:

1. Boulders & Cobbles – Require highest energy to transport.
2. Gravel – Deposited next as flow weakens.
3. Sand – Settles in moderate currents.
4. Silt – Needs very slow water.
5. Clay – Stays suspended longest; deposits last in nearly still water.

Graded Bedding

This vertical sorting—coarse at bottom, fine at top—is called graded bedding, a hallmark of waning flows in rivers, deltas, and turbidity currents.