RFI - Attachment E - SWMP Callaghan and Toth

                                                                               Callaghan & Toth


Biobasin 1 will be:
           a. Located in Lot 7 SP173177 in the same footprint of the existing biobasin
                adjacent to Cooroy Creek.
           b. Designed with a filter area of 144m2.
           c. Filter layer depth of 0.5m, transition layer of 0.1m and drainage layer of 0.2m and
                an extended detention depth of 0.3m.
           d. The size and depth of the systems have been designed in accordance with
                Water by Design Guidelines and IPWEAQ standard drawings in Appendix C.

Biobasin 2 will be:
           a. Located in Mary River Road road reserve in the same footprint of the existing
                biobasin adjacent to Cooroy Creek.
           b. Designed with a filter area of 26m2 (3m wide x 8.65m long)
           c. Filter layer depth of 0.4m, transition layer of 0.1m and drainage layer of 0.2m and
                an extended detention depth of 0.3m.
           d. The size and depth of the systems have been designed in accordance with
                Water by Design Guidelines and IPWEAQ standard drawings in Appendix C.

Grass Swales will form part of the treatment train, with two existing grass swale accepting flows
from carpark areas adjacent the buildings and one new swale diverting flows to the biobasin
BB1.

Swale 1
       Existing swale located in Lot 5 formalised,
       Length of 60m, top width of 4.2m, base width of 0.2m with 1 in 4 batters,
        approximate grade of 1.0%.
       The size and depth of the systems have been designed in accordance with Water by
        Design Guidelines.

Swale 2
       Located in Lot 7 one new swale adjacent the new carpark,
       Length of 40m, top width of 2.6m, base width of 0.2m with 1 in 3 batters,
        approximate grade of 1.0%.
       The size and depth of the systems have been designed in accordance with Water by
        Design Guidelines.

Swale 4
       Existing swale located in drainage easement between Lot 4 and Lot 5.
       Length of 40m, top width of 4.2m, base width of 0.2m with 1 in 4 batters,
        approximate grade of 1.0%.
       The size and depth of the systems have been designed in accordance with Water by
        Design Guidelines.

4.3.3 Rainfall Data

The meteorological data used for the MUSIC Model was the data for Cooroy from 01/01/73 –
31/12/83.

The mean Annual Rainfall for Cooroy                 1973 – 1983 = 1600mm

The MUSIC Modelling Guidelines for South East Queensland – Version 1 December 2010
details that Cooroy data for 1973 to 1983 should be used.


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2001 Lower Mill Carpark Extension SWMP                                          July 2020