A detailed study of the settling velocities of an estuary mud

Detailed tests on a mud, obtained. from Avonmouth in the Severn Estuary, were carried out in bottom withdrawal tubes up to 2.0 metres high to determine the effect of suspended, concentration, salinity, and depth of settling on the sedimentation rate.
The settling velocity was found to increase with concentration up to about 14 g/l, when hindered settling begins, and with salinity up to about 30 g/l. Initially the settling velocity reduced with increasing depth, reaching a minimum value at about 1.0 metres but it increased thereafter up to a depth of about 2.0 metres, when settling velocity became constant.
A review of the basic theory of flocculation is included.