Landcom Book 4 Maintenance - WSUD

Water Sensitive Urban Design
Examples of sedimentation basins and ponds
3.3 Sedimentation Basins
Due to the nature
of a sedimentation
basin, regular clean
out and removal
of accumulated
sediment is
required.
Sedimentation basins are stormwater
detention systems that promote the
settling of coarse sediment (defined
as particles greater than 125 microns
in diameter). A sedimentation basin
can be an integral part of a treatment
train, providing primary removal of
coarse sediment. Removal of coarse
sediment is particularly important in
protecting downstream systems from
high sediment loading, which can reduce
the effectiveness of the system. The
treatment performance of a bioretention
system is particularly susceptible to high
sediment loadings: sediment can smother
vegetation and clog the filter media
affecting the percolation of stormwater
through the media. Sediment basins can
also be employed for temporary sediment
and erosion control during construction
activities.
Due to the operation of a sedimentation
basin, regular clean out and removal
of accumulated sediment is required.
Sedimentation basins are generally
designed for a clean out frequency of
five years, which equates to a volume
half that of the permanent pool (defined
by the invert of the outlet structure).
The sedimentation basin design should
include an access ramp to allow entry for
a clean-out truck.
Book 4 | MAINTENANCE 11