Response to Information Request - Received on 19/04/2012 · OPW11/0335

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                                                                                                                     8      U   T     L     E    R
                                                                                                                     PARTNERS



                                          Residential Development
                          215-219 David Low Way, Peregian Beach
                    Draft Acid Sulfate Soil Management Plan (ASSMP)
  Element                       Acid Sulfate Soil Management Plan

  Objectiverrarget              The objective of the ASSMP is to control net acidity levels within soils disturbed during
                                site development works, and to restrict to an acceptable level any potential on-site and
                                off-site environmental impacts during site redevelopment.
 ASS Management                 To mitigate and manage potential environmental impacts associated with ASS during the
  Strategy                      redevelopmep~~ W k~ Jhis>.~’Yill be achieved by havln~ a mat~rials handling and
                                managem~l:sfrategy In: BJ .$6; as well as procedures for either on-site lime treatment of
                                soils or,
                                located
                                            t~(apprOPria.~;Ifff-site treatment of soils (if suitably sized and appropriately
                                          spice is not va able}er’on-sile treatment).
                                                                                                          a



 Tasks/Actions                  An ASS      invesltgffiJ1tr has,!.l~efii ltj~d out to     assess the soils within the               redevelopment
                                site, to a maximum dep’W f 2.5m b.51IQW, the existing surface level. Fill materials, sands
                                and silty sands have’l’l en sho~n tdW6       negligible levels of net acidity and do not
                                                                               nta.i.o
                                require treatment for ASS. Ho,~v J"tl)e nafi.jfal dark grey-brown, silty clays encountered
                                                                        [1l’2)’to contqj .]eY(lls of net acidity that exceed
                                in Bores 1 and 2 have been sJi wn (iri ’B
                                the State
                                           Pla~ning Policy      2/02,~c, ~9&ril
                                                                             ria              9~d:q~
                                                                                          O/~S: JIle natural silty clays will
                                                                                                ’/
                                therefore reqUire treatment as      folfow~? .

                                                                                         ’.
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                                                                                                              f,,;;,~.>t’
                                .   If on-site treatment is undertake~ then’Jinfu treatme’rit’ f the soils will be undertaken
                                                                                                                      .




                                    as described below.
                                                                               ’Jt_r ,{:{"          htl
                                    Where on-site treatment is not possible ’m ’silty clays will be excavated, then
                                    transported in a sealed truck to an appropri 1~1y designed off-site treatment area for
                                    neulralisation.

                                ASS Treatment On-Site

                                    Any silty days exposed in the base of the basement excavation will require an
                                    application of ag-lime at a rate of 5 kg/square metre.
                                .   Where eXC<lvated silty clay soils are to be treated on-site, a suitably sized dedic.ated
                                    treatment area will be created. Soils to be treated shall be placed on the treatment
                                    area in    layers not thicker than 0.3m.
                                    Bunding will be constructed around the perimeter of the designated treatment area
                                    to intercept and contain run-off from the area during the Soil treatment operations.

                                    The base of the treatment area is to be lime treated prior to placement of each layer
                                    of excavated material. Re-treatment with ag-lime is required prior to placement of
                                    each new layer of excavated material to be treated, and at the conclusion of all
                                    treatment. The base of the treatment pad shall have a minimum ag-lime application
                                    of 5 kg/square metre.

                                .
                                    Ag-lime will be applied evenly over the surface of the treatment area and thoroughly
                                    blended into the ASS at a rate of 3 kg of ag-lime/tonne of dry silty clay soil. This
                                    liming rate is based on a factor of safety of 1.5 and the use of good quality fine ag-
                                    lime with a neutralising value of not less than 80 %.

                                    When incorporation of the lime is complete, chromium suite validatien testing of the
                                    treated spoil will be carried out to establish that sufficient ag-lime has been added to
                                    neutralise the acid generation potential of the spoil. Where validation testing fails to
                                    meet performance indicators, application of additional ag-lime will be required until a
                                    satisfactory net acidity validation result has been achieved.
                                .   Once ag-lime treatment is complete, the treated spoil may then be stockpiled for
                                    later use or off-site disposal (as appropriate).

                                    Should the proposed depth of disturbance extend below 2.5m in depth from surface
                                    level, then additional ASS testing will be required.
                                    Lime-treated, stockpiled soil shall have sediment fences and/or hay bales placed
                                    downslope to intercept any eroded material. arthen bunds shall be constructed
                                    downslope of stockpile areas to divert run-off/drainage to a collection sump. The
                                    water quality of the sump is to be monitored against the water quality objective


Residential Development                                                                                                                   Appendix C
215-219 David Low Way, Peregian Beach                                                                                                     Page 10f3
Project No. 07160                                                                                                                      18 June 2007