Revised Stormwater Management Plan

                              STORMWATER MANAGEMENT PLAN
Client: Hass Holdings ATF The Quasar Trust                                                Location: Taylor Court, Cooroy

6.3.3 Existing and Proposed Development Areas

The total catchment area has been modelled as one (1) catchment. The existing and proposed
catchment boundaries are the same for each modelling scenario. Refer to Figure 5 for the
stormwater quantity catchment boundary. Refer to Appendix F for a detailed Stormwater Quantity
Catchment Plan.




                               Figure 5 Stormwater Quantity Catchment Boundaries

6.3.4 Initial and Continuing Losses
Initial and Continuing Rainfall Loss parameters were adopted as per Table 8.

                                      Table 8 – Initial and Continuing Losses

                                          Pervious Catchments                     Impervious Catchments

                                      Initial Loss              Cont. Loss      Initial Loss         Cont. Loss
                 Event                   (mm)                    (mm/hr)           (mm)               (mm/hr)
               AEP 1%                     0                        2.5               0                   0
          AEP 10% and 39%                12.5                      2.5               0                   0

6.3.5 Pervious and Impervious Areas

The proposed development site and external catchment in its existing state has a total area of
0.924 ha and is completely pervious.

The proposed development and external catchment has a total area of 0.924 ha and a proposed
impervious area of 0.63 ha for the developed case, equating to 62%. This will increase total
contributing catchment’s percentage impervious from 0% to 62%.

All pervious and impervious areas for the existing and developed scenarios are detailed in Table 9.

                           Table 9 – Existing and Developed Catchment Areas and Slopes
                             Catchment           Area               Pervious     Impervious            Slope
                                                     (ha)                (ha)            (ha)            (%)
        Existing             Site                0.92                    0.92           0                5
        Developed            Site                0.92                    0.29         0.63               5

The stormwater quantity catchment boundaries are shown in Appendix F.
Covey Associates Pty Ltd                                    9                                         Project No: 161968
Consulting Engineers                                                                                     100415 Rpt Iss B