Reference Document - OPW23 0189

Project No. PG-10899                                                                                                        Page | 1
November 2023
Ref: PG-10899, 2023-10-16, ASSMP VER 2
DD Sunnyside CD Sunnyside Pty Ltd – Acid Sulfate Soil Management Plan – Proposed Residence, 30 Mossman Court, Noosa Heads




                  ACID SULFATE SOIL MANAGEMENT PLAN (ASSMP)
                                    PROPOSED RESIDENCE
                              30 MOSSMAN COURT, NOOSA HEADS
Objective                            The objective of the ASSMP is to control any acid generation from
                                     insitu ASS materials and to restrict to an acceptable level any
                                     potential on-site and off-site environmental impacts. A further
                                     objective is to manage earthworks activities and provide measures
                                     to maintain water quality within the site and in adjacent areas.
Proposed                             It is understood that the proposed development is to comprise the
Development                          construction of a two storey residence with a basement.
                                     Earthworks are envisaged to consist of cuts of up to 3m for the
                                     basement.        A total volume of material to be disturbed is
                                     approximately 900m3. Additional investigation and testing will be
                                     required to confirm the results and recommendations of this
                                     management plan.
Subsurface                           Mapping
Conditions                           The site is located in an area that is mapped on the Noosa Council
                                     Acid Sulfate Soils Mapping as Disturbed Land likely to contain ASS.
                                     ASS Investigation
                                     Drilling and sampling encountered a reasonably consistent profile
                                     of sand that:
                                     • did not indicate any obvious ASS presence from a visual and
                                           tactile perspective in the fill or the natural profile.
                                     •     indicated that the upper level sands were not acid sulfate soils
                                           and the lower level sands below 3.0m indicated a low level of
                                           acid sulfate soil present.
                                     •     had the highest liming rate required to neutralise the acidity of
                                           4kg/m3 (based on laboratory testing of selected samples) for
                                           the lower level sands.
                                     •     The proposed excavations for the basement (up to 3.0m
                                           depth)are not expected to disturb the acid sulfate soils but may
                                           just indicate the acid sulfate strata.
Management                           To mitigate and manage potential adverse environmental impacts
Strategy                             during site construction operations, the following will be
                                     undertaken:
                                     • an ASS consultant should review the site earthworks schedule
                                         and plan of operations;
                                     •     adoption of appropriate erosion control measures to limit
                                           sediment loss due to run-off from site works area;
                                     •     where excavation below the water table, or if disturbance of
                                           any silty sands is necessary, a materials handling and
                                           management strategy and procedures for lime treatment of
                                           any disturbed material will be required;
                                     •     monitoring and treatment (if necessary) of waters in detention
                                           basins to a level suitable for discharge into external waterways;
                                           and
                                     •     site supervision by approved persons and regular reporting to
                                           the Project Engineer/Manager throughout the construction
                                           phase.