Response to Information Request · OPW11/0177

                                                     TATE PROFESSIONAL ENGINEERS PTY LTD
                                                                                ABN 28 086 262 035




        5.   Detail the RL of the overflow of the underground rainwater tanks and inlet to the Rapid
             Infiltration Pits on the submitted drawings.

        We note that proposed rainwater harvesting tanks as indicated on drawing D01 C occur above
        proposed ground floor level of RL21.5m AHD and the tops of the proposed RIP's are to be at
        RL18.45m AHD.

        As such there will be no shortage of fall or gradient required to achieve adequate overflow of
        tanks to the RIP's.

        Building drainage, guttering, spouting, etc is beyond the scope of this Operational Works
        application and hence details of such are not included at this time but will be addressed in future
        hydraulic consultant's applications as appropriate.




        6.   Provide in situ hydro conductivity testing to confirm that the assumptions made on soil
             permeability and infiltration rate of the insitu soils are accurate.

        Infiltration rates applied to the RIP analysis spreadsheet are derived from in-situ prototype testing
        carried out by Tate Professional Engineers (refer Appendix B of Stormwater Management Plan)
        with a factor of safety of two (2) applied. Such results have been accepted for all previous
        Operational Works applications and the higher order MCU approval and management plans
        controlling development of the entire Settlers Cove site.




        7.   Demonstrate that scour along the downstream batter / weir of the turfed swale along
             the rear boundary will not occur in a major storm event.

        Rapid Infiltration Pits proposed along the site's northern frontage have been designed to infiltrate
        stormwater runoff for events up to 100 year ARI without overtopping and with a factor of safety of
        two (2) applied.

        In addition to this a swale around 60m long x 2m wide and with a depth of 0.35m is proposed
        above surcharge levels of the RIP's to contain and further infiltrate runoff from storms of "biblical
        proportions".

        By adopting a level Swale along the full length any discharge from the Swale during such
        incredibly unlikely storm events would be dispersed along the full length of the swale so as not to
        cause scour of the escarpment.

        As such Condition 22 of the MCU decision notice is satisfied.


Weru7 this adequately addresses all issues raised and look forward to receipt of a decision notice.

Yours faithfully


Sted.HHarrison - Director
for AMTE. PROFESSIONAL ENGINEERS PTY LTD
Encl/        Dwg S3000/08/L5-6/D03D

Cc:          Mr Gary Godfrey


S3000/111L5/Response to Information Request - Sunshine Coast Regional Council
SH/cw