080624 2383-01 FINAL Engineering Report for DA.pdf [As Published] · 132008.1128

BLUE CARE SUNRISE BEACH
ENGINEERING REPORT FOR DEVELOPMENT APPLICATION


    Infiltration losses from the systems will, almost certainly, exceed the values of 0.02m3/s
    to 0.03m3/s required for the basin peak discharges, from the developed site, for the 2
    year ARI events, to be reduced to values less than those from the undeveloped site.

     When allowance is made for these losses, the basin peak discharges, for all average
    recurrence intervals, are less than those from the undeveloped site.

    2.6.4          Summary

    Significant attenuation of peak discharges from the proposed development is required to
    ensure that discharges to the Noosa National Park are not worsened, compared to
    those from the current undeveloped site. It is proposed to provide the storage required
    to achieve this attenuation in two separate basins located adjacent to the northern
    boundary of Lot 6 and the western boundary of Lot 1. The detention basins will be
    combined with the bioretention basins required for stormwater runoff quality treatment.

    Discharges from the basins will be converted from concentrated to sheet flows by
    means of spreader channels constructed within the 10m fire break within the buffer
    areas to the national park.

    Modelling, using the XP-SWMM package, has demonstrated that satisfactory
    attenuation of peak discharges from the development can be achieved.




Blue Care Property Development Unit                 Version 1.1                              24 June 2008
2008 06 24 2383-01 Engineering Report for DA   Commercial in Confidence                           Page 13