O2 stormwater Report Rev Oct 2015

Table 14 – Estimated Soil Loss and Risk Categorisation for Varied Slope Lengths and Grades




Based in the Erosion Risk Assessment undertaken, it is concluded that the site presents only a Very Low or
Low erosion risk, as slopes are typically less than 0.5%, increasing to approximately 2% in some areas
adjacent to the creek.

Based on these factors, soil loss for disturbed areas is estimated as less than 150 t/ha/year.

6.2.          Erosion Control and Rehabilitation
Based on the erosion risk rating, the following best practice land clearing and rehabilitation controls should
be applied:
         Land clearing limited to a maximum 8 weeks of work.
         Disturbed soils surfaces stabilised with minimum 70% cover within 30 days of completion of works
          within any area of a work site.
         Unfinished earthworks are suitably stabilised if rainfall is reasonably possible, and disturbance is
          expected to be suspended for a period exceeding 30 days.

During the site inspection, a number of disturbed areas were observed. These should be stabilised as soon
as possible, using turf or topsoil and hydromulch, or other vegetative cover.

However, should stabilisation not be achievable using permanent specifications, any of the temporary
controls presented in Table 17 may be utilised.
Table 15- Stabilisation Materials

Flat Land (<1 in 10)                                                   Mild Slopes (1 in 10 – 1 in 4)

Erosion Control Blankets                                               Bonded Fibre matrix
Gravelling                                                             Compost Blankets
Mulching                                                               Erosion Control Blankets, Mats and Mesh
Revegetation                                                           Mulching well anchored
Rock Mulching                                                          Revegetation
Geofabric (temporary)                                                  Rock Mulching
Black plastic (temporary)

Stormwater Management Plan – Lot 1 on SP108094, 305 Lake Macdonald Drive                                         Page 20

D’VINERIPE
R003370a