The mud that ends up at the bottom of a lake usually falls through the water first.
Sediment traps collect the solid material that rains out of the water over a period of time.
The Bear Lake sediment trap automatically drops white Teflon marker beads into the collecting tube every 30 days, so that the tube ends up holding a sequence of layers made of sediment and white beads. Diagram of Sediment Trap Mouth of sediment trap showing the honeycomb baffles that direct particles into a plastic accumulation tube.