RFI - Attachment B - Stormwater management Report · MCU20/0026

Table 6 – SPP Appendix 2: Part 2 Construction Phase – Stormwater Management Design Objectives
for Temporary Drainage Works

 Temporary Drainage Works                         Anticipated Operation Design Life and Minimum
                                                               Design Storm Event


                                                  <12 Months            12-24 Months      >24 Months

 Drainage Structure                               1 in 2 year            1 in 5 year    1 in 10 year
                                                 ARI/39% AEP            ARI/18% AEP    ARI/10% AEP

 Where located immediately up-slope of an                      1 in 10 year ARI/10% AEP
 occupied property that would be adversely
 affected by the failure or overtopping of the
 structure

 Culvert Crossing                                               1 in 1 year ARI/63% AEP


Table 7 – SPP Appendix 2: Part 3 Construction Phase – Stormwater Management Design Objectives
for Emergency Spillways on Temporary Sediment Basins

               Drainage Structure                 Anticipated Operation Design Life and Minimum
                                                               Design Storm Event


                                                   <3 Months            3-12 Months       >12 Months

 Emergency spillways         on     temporary     1 in 10 year          1 in 20 year      1 in 50 year
 sediment basins                                 ARI/10% AEP            ARI/5% AEP        ARI/2% AEP

Best practice erosion and sediment controls must be installed to minimise the discharge of sediment
laden runoff during construction and to achieve the objectives outlined in Tables 7-9. This is discussed
in the following section.
4.2.2 E ro sio n and Se di men t Co n tr ol

The proposed development received an erosion hazard score of 19. Refer to Appendix A for details.
Erosion and sediment control plans shall be developed during the detailed design phase in accordance
with the requirements outlined in the International Erosion Control Association (IECA) 2008 best
practice documentation. Erosion and sediment control plans are based on three sets of control
measures:
       drainage control;

       erosion control; and

       Sediment control.
These control measures must be continually maintained in an effective operational condition and
amended as required to minimise environmental harm. Sediment disposal from site is to occur to the
satisfaction of NSC and the following release limits of stormwater captured in a sediment basin shall be
adhered to:



11 June 2020                            Stormwater Management Report                                   10
S20-023                               40 Park Crescent, Sunrise Beach