How does a CSE excavate sediments with a reduced moisture content?
The CSE is a mechanical dredge bucket that is contained within an enclosure or housing. As the CSE descends underwater, compressed air is introduced into the housing at a pneumatic pressure that is balanced against the hydrostatic pressure outside of the housing. As long as the pressure inside of the housing is equivalent to that of the external hydrostatic pressure the internal housing is maintained water-free. As a result, the CSE can be lowered to the bottom of the waterway and an excavation can be made in a dry environment. Excavating in a dry environment prevents the water column from mixing with the excavated muds during the dredge removal process resulting in the removal of sediment with a moisture content at or near the in-situ moisture content of the sediment (no free-water).
