What Rivers Carry in Suspension: Fine Particles

Suspended Load Composition

When river velocity is sufficient to keep particles aloft but too low to move larger material, the following travel as suspended load:

• Clay particles (< 0.004 mm)
• Silt particles (0.004–0.0625 mm)
• Fine sand (0.0625–0.25 mm) – at higher flows
• Organic matter (detritus, algae)
• Colloidal particles (< 0.001 mm) – stay suspended for long periods

Contrast with Bed Load

Coarser sand, gravel, cobbles, and boulders move as bed load (rolling, sliding, saltating). Suspended load gives rivers their muddy color and builds floodplains/deltas upon deposition.