Compiled Reference Documents - MCU25/0091 (As Published)

            Wingara Hills Pty Ltd

            used as irrigation provided it is disposed of in a manner appropriate for its end use as indicated in the QPW
            Code.
            Land application of secondary treated wastewater using surface irrigation (spray or drip) is limited to ground
            slopes less than 10% (about 6°). Subsurface irrigation may be adopted for ground slopes up to 30% (about
            17°).
            Based on Table 5.2 and Table M1 of AS1547 and adjusted for slope angle in accordance with Table M2, a
            Design Irrigation Rate (DIR) of 1.5 mm/day is considered appropriate for the proposed facility. This allows for
            a sloping site of up to 30%, whereby the DIR of 3 mm/day for a Category 5 soil is reduced by 50%.
            For Category 5 soils, Table M1 of AS 1547 recommends that a drip irrigation system have a depth of
            150 mm to 250 mm in good quality topsoil.
            Therefore, about 400 m² of irrigation area would be required for an assumed total wastewater flow rate of
            600 L/day. Indicative irrigation areas are shown on Figure 1. The disposal field may be split into two or more
            areas but must total at least 400 m2.
            Positioning (‘setbacks’) of the land application systems should be in accordance with the horizontal
            separation distances recommended in the QPW Code as outlined in Table 4.
            Table 4: Horizontal separation distances for irrigation areas

                            Description                      Secondary Effluent              Advanced Secondary Effluent
                To permanent/intermittent
                watercourse, dam, drainage                            30 m                                  10 m
                channel
                To bore or well used for domestic
                                                                      30 m                                  10 m
                water supply
                Property boundaries, paths,
                walkways, recreation areas,
                                                                   4m/2m                                 4m/2m
                footings of buildings, retaining
                walls
                In ground potable water tank                          6m                                    6m
                Dwelling, recreation area
                                                                      10 m                                  10 m
                (surface irrigation only)
                Water edge of swimming pool,
                                                                      6m                                    6m
                cutting in soil

            An unsaturated soil depth of 0.6 m (i.e. depth to rock or wet soil) is recommended in the QPW Code for
            Secondary effluent. Test pits in the vicinity of the proposed irrigation area indicate sufficient available soil
            depths and absence of groundwater to at least 0.6 m depth.
            The system may be required to be positioned upslope or at a reduced level similar to proposed buildings
            whilst adhering to the separation distances recommended in the QPW Code (Table 7) and will require a
            suitable pump system.

            8.3.1 System Construction
            Construction of the wastewater land application area should be carried out in accordance with Section 6 of
            AS 1547 and Sunshine Coast Council requirements. In order to minimise potential deleterious
            environmental impacts associated with wastewater application at the site, the following practices should be
            employed:

                  The subsurface irrigation field(s) is to be located on land sloping at less than 17° (indicative suitable
                   areas are shown on Figure 1). Alternatively, a disposal field could be created on steeper land using
                   cut/fill earthworks supported by a retaining wall. It is anticipated that for such a field, the wall would be
                   generally less than 1 m high. If cut is undertaken, it must be limited to ensure at least 600 mm of soil
                   overlies rock. Fill must be limited to no more than 1 m high.




            J002915-001-R-Rev0                                   13


Document Set ID: 24031832
Version: 1, Version Date: 14/08/2025