GEOLOGY

Detailed explanation-1: -As the particle size gets larger, the minimum flow velocity needed to erode the particle decreases, with the lowest flow velocity being 30 centimetres per second to erode a 0.5 millimetre particle. To erode particles larger than 0.5 millimetres, the minimum flow velocity rises again.

Detailed explanation-2: -Deposition starts to occur at cm per second for particles of approximately 0.01mm in size. Boulders require the smallest velocity for deposition, at only cm per second for the smallest boulders 250mm in size.

Detailed explanation-3: -On the other hand, a 0.01 mm silt particle only needs a velocity of 0.1 centimeters per second (cm/s) to remain in suspension, but requires 60 cm/s to be eroded. In other words, a tiny silt grain requires a greater velocity to be eroded than a grain of sand that is 100 times larger!

Detailed explanation-4: -At 100 cm/s, for example, silt, sand, and medium gravel will be eroded from the stream bed and transported in suspension, coarse gravel will be held in suspension, pebbles will be both transported and deposited, and cobbles and boulders will remain stationary on the stream bed.