Landcom Book 4 Maintenance - WSUD

Water Sensitive Urban Design
6.1.1 Stage 1: Civil construction (or functional installation)
Stage 1 requires the construction of the functional components for the WSUD element.
The functional components for the WSUD elements addressed in the booklet are:
Bioretention basin Constructed wetland Sedimentation basin
Bulk earthworks to
establish bunds and system
batter slopes
Detailed profiling of bunds,
batters, sides and base
of system to meet design
requirements (given
allowed tolerances)
Construct all hydraulic
structures, for example,
inlet pipes and headwalls,
bypass weir, outlet riser and
rock protection*
Install system lining,
underdrainage, clean out
points and various layers
(that is, drainage layer,
transition layer and filter
media)
Survey wetland layout in
accordance with the design
Remove ground cover and topsoil
as indicated from the survey
Stockpile topsoil designated for
reuse in construction, noting
that the soil must be tested
and screened to remove coarse
sediment and weed seeds
Bulk earthworks to establish the
inlet and macrophyte zone, high
flow bypass and surrounding
bunds and batters
Detailed profiling of bunds,
batters, sides and base of system
to meet design requirements
(given allowed tolerances as
well as 300 mm of topsoil and
impervious liner, if specified)
Install impervious liner (if required)
Construct bunding between the
inlet and outlet zone, as well as
between the wetland and lake (if a
lake is included in the design)
Construct all hydraulic structures,
for example, inlet pipes and
headwalls, bypass weir, outlet riser
and rock protection*
Topsoil placement and profiling to
within accepted tolerances
Bulk earthworks to
establish bunds and system
batter slopes, as well as
maintenance access (e.g.
ramp)
Installation of outlet
structures (for example,
overflow pit / weir and
spillway)
Installation of inlet
structures including inlet
pipe and headwall.
For a sedimentation basin,
install the inlet energy
dissipater and primary
treatment measure (for
example, gross pollutant
trap)
Detailed profiling of
bunds, batters, system
base, access points and
spillway to meet design
requirements (given
allowed tolerances)
Install system lining
Stabilise system batters
and base with sterile grass
NOTE:
* This is not a complete list of hydraulic, functional and structural elements of a constructed wetland – the
reader is referred to the Water by Design documents for complete details.
Immediately following completion of stage 1, sediment fences should be installed at the
top of the system batter. Bioretention basins will also require sediment fences installed
around the filter media.
40 Book 4 | MAINTENANCE