17155 - Stormwater Quantity Assessment Letter - Rev 0 · OPW17/0612

                                                                        MORGAN CONSULTING
                                                                       E NGINEERS P TY LTD
                                                                                  16003/CG
                                                                                      Page 6




3.0 Conclusion

RAFTS modelling confirmed that by implementing detention throughout the development
the post development discharge will be below pre development discharge for the 2, 5, 10,
20, 50 and 100 year ARIs.

Although XP-RAFT modelling confirmed there still remains a minor increase in the post
development 1 year ARI storm event flow further mitigation will be provided by the storage
within the extensive pipe network, bio-retention basins and swales within the development.

It has also been confirmed that the existing stormwater infrastructure and property
connections for the development within Resort Drive have been designed and have sufficient
capacity to cater for the post development 10 year ARI event flows. Therefore the minor
increase in the 1 year ARI can be catered for within the existing network.

Based on the analysis in this letter, all stormwater from the development will be collected,
mitigated and discharged via the existing pipe network in Resort Drive to ensure no harm to
the receiving natural and built environments.

Please contact me if you have any further queries on (07) 3369 8411.

Yours faithfully,

M ORGAN C ONSULTING E NGINEERS P TY LTD




Henry Morgan        RPEQ 11950
Director