Engineering IR Response

Detention will be incorporated in the post-development scenario for the minor events that will
discharge into the existing kerb and channel. XP-STORM V2017.2 was used to determine the
detention volume required and the results are illustrated in Table 1.1. Table 1.1 illustrates that
10kL of detention with two 100mm diameter outlet mitigates the minor event discharge to less
than the required 25L/s flow rate and less than the pre-development scenario.


A concept stormwater management plan has been provided in Attachment 1, and hydrographs
have been attached in Attachment 2.


                   AEP (ARI)    Pre-Development         Post-Development Peak
                                Peak Flows              Flows (Mitigated)

                   50% (2yr)    0.024                   0.015
                   20% (5yr)    0.033                   0.018
                   10% (10yr)   0.043                   0.020
                   5% (20yr)    0.049                   0.021
                   2% (50yr)    0.046                   0.023
                   1% (100yr)   0.051                   0.025

                           Table 1.1 – Pre vs Post Development Discharge