Appendix F - Geo-Environmental Investigation Report · RAL24/0003

                             PROPOSED SUBDIVISION
                             41 TALLOWWOOD PLACE, BLACK MOUNTAIN

7.4.3        System Construction
Construction of wastewater land application areas must be carried out in accordance with Appendix M of
AS1547:2012 and NC requirements. In order to prevent any adverse impacts on the water quality from
effluent disposal, the elements given below shall be implemented:
       Shallow subsurface drip systems must be installed at 100 mm to 150 mm depth into 150 mm to
        250 mm of good quality sandy topsoil, in grassed of other suitably vegetated areas. Any sandy
        topsoil material won from site works may be used to supplement the soil within the respective
        disposal fields or alternatively shall be imported to the site.
       Receiving native soils will be prepared by undertaking deep ripping / shallow cultivation combined
        with the addition of organic matter (10 kg/m² raw mulch), together with gypsum (1 kg/m²) to ‘break
        up’ any relatively hard clay subsoils, as required, and improve overall drainage characteristics.
       Shallow subsurface irrigation lines will run parallel to slope contours. To evenly distribute
        wastewater throughout the irrigation areas, pressure equalisation systems (i.e. pressure
        compensating drip emitters) should be installed.
       Surface diversion drainage shall be installed on the up-slope sides of the land application areas to
        divert surface water and shallow subsurface seepage flows away. Such drainage should penetrate
        to a minimum depth of 0.3 m BGL.
       A low earthen bund shall be constructed, down slope of the effluent disposal areas up to 0.3 m high
        to retain run-off and promote sheet flow.
       Plant and maintain grasses, reeds and/or small shrubs within the land application areas. Preference
        should be given to native plant species endemic to the local area, which are suitable for mostly wet
        soils and are tolerant of nutrient loads (e.g. native riparian vegetation)
       Erect signage at the boundaries of the area in at least two places in accordance with Council
        requirements to warn people regarding the presence of wastewater pipes (e.g. “Sewage Effluent
        Pipework Installed Below – DO NOT DIG” or “Recycled Water – Avoid Contact - DO NOT DRINK”).
       Erect barriers where necessary to restrict access to public which may interfere or damage the
        irrigation system.

Detailed design of the effluent disposal system must be carried out by an NC registered evaluator to
accompany the plumbing application at the building stage, once the building designs are finalised.
7.4.4        Maintenance and Inspection
Operation and maintenance of a HSTP is the responsibility of the property owner. A licensed service agent
must be appointed to undertake routine servicing works in line with regulatory authority approval conditions.
To comply with NC requirements, the following management and inspection shall be implemented once the
effluent disposal systems are established:

       Continuous monitoring by the property owner for any signs of system failure such as septic odour,
        seepage, soil and/or plant discoloration.

       Should any signs of system failure be observed by the property owner, including the in-built HSTP
        failure alarm, the manufacturer shall be contacted immediately to arrange for the necessary repairs.

       Quarterly inspection, testing and repair (if necessary) to the HSTP and irrigation area by a Licensed
        Inspector (normally a service provided by the HSTP manufacturer).


8.0      LIMITATIONS
Your attention is drawn to the document Limitations, which is included in Appendix D of this report. The
statements presented in this document are intended to advise you of what your realistic expectations of this
report should be, and to present you with recommendations on how to minimise the risks associated with the
services provided by Tectonic for this project.


22 May 2023
Report No. 23099-001-Rev0                              22