Attachment 6 - Stormwater Management Plan

R1767: NOOSA LANDFILL: CLEAN WATER DRAIN AND HES BASIN (SW5) – DESIGN REPORT & MAINTENANCE AND INSPECTION PLAN




Figure 1 – XP Model for Drainage Assessment

5.1.                RAINFALL

Modelling was undertaken for 10 % and 1 % Annual Exceedance Probability (AEP) storm events for durations between 15
minutes and 3 hours. Intensity Frequency Duration (IFD) data for the hydrologic modelling was obtained from the Bureau
of Meteorology website, and has been developed in accordance with Australian Rainfall and Runoff (ARR) 2016. The IFD
data is summarised in Table 2.

Table 2 – Intensity Frequency Duration Data

    DURATION (mins)                    10 % AEP (MM/HR)              1 % AEP (MM/HR)

                  15                        152.0                            217.0

                 20                         133.0                             191.0

                 25                          119.0                           172.0

                 30                         108.0                            158.0

                 45                          87.1                            129.0

                 60                          74.2                             112.0

                 90                          59.0                             90.7

                 120                         50.1                             78.1

                 180                         39.8                             63.3



5.2.                PEAK FLOW RATE

A range of design storm durations was assessed to ensure the critical duration event was taken into consideration. The
Guideline - Stormwater and environmentally relevant activities (EHP, 2014) requires that high erosion hazard sites
implement the following design and management measures:



Environment. Engineering. Education.                                                                             PAGE 4