Reference Document - OPW25 0085 (AS Published)

Table 6: Setbacks for subsurface land application area for on-site sewage treatment plant
                                                                 Horizontal separation distance
                          Site Feature
                                                             Upslope       Downslope           Level
 Property boundaries, pedestrian paths, walkways,              2m               4m              2m
 recreation areas, retaining wall, and footings for
 buildings and other structures.
 Inground swimming pools.                                                       6m
 Inground potable water tank.                                                   6m
 (Secondary standard effluent or better)

Note: Distances measured from the edge of trench/bed excavation or subsurface irrigation distribution
pipework to the nearest point of the feature.

Table 7: Setbacks for surface irrigated land application area for on-site sewage treatment plant
                          Site Feature                           Horizontal separation distance
 Property boundaries, pedestrian paths and walkways                             2m
 Water edge of a swimming pool                                                  6m
 Dwellings, recreation areas                                                  10 m
Note: Distances measured from the edge of the irrigated wetted area to any point of the feature.

Table 8: Setback distances for on-site sewerage facilities (Protection of surface and groundwater)

                                                                       Separation Distance
                          Site Feature                     Advanced Secondary        Secondary Effluent
                                                                Effluent
 Surface Waters:                                                  10 m                     30 m
     Top of bank of permanent or intermittent water
      course, lake, bay or estuary;
     Top water level of a surface water source used for
      agriculture, aquaculture or stock purposes;
     Open stormwater drainage channel or drain;
     Bore or a dam.
 Unsaturated soil depth to a permanent water table                0.3 m                    0.6 m
 (vertically)
Note: Distances measured from the edge of the irrigated wetted area to any point of the feature.

Investigation test pits did encounter isolated seepage in some sandy layers however generally indicate
adequate unsaturated soil depths are available across the respective anticipated building and application
areas.
The conceptual wastewater layout is shown in Figure 1 Site Plan, where it can be seen that a suitably
sized wastewater treatment and disposal areas can be positioned within each proposed allotment. It is
noted that this plan demonstrates conceptual layout only for the purpose of demonstrating feasibility.
Individual site layouts shall be decided at building stage.


Geo-Environmental Investigation for Proposed Subdivision
7 February 2025 | 24386-001-Rev0                                                                          25