SUPERSEDED - Reference Documents - MCU25 0079

                 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 4-6. This is discussed
                 in the following section.
                 4.2.2 E ro sio n and Se dim en t Co ntr ol

                 Management of stormwater runoff during construction is necessary to avoid pollution of downstream
                 waterways from sediment and gross pollutant loading. Impacts of inadequate erosion and sediment
                 control downstream from the site include:

                     •    traffic safety problems;

                     •    blocked drains;

                     •    local flooding problems;

                     •    aesthetic pollution of drainage paths; and

                     •    damage to local ecosystems.

                 Best practice erosion and sediment controls must be installed to minimise the discharge of sediment
                 laden runoff during construction. Erosion and sediment control plans shall be developed during detailed
                 design phase and must be continually maintained and amended as required to minimise environmental
                 harm.

                 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 maintained in an effective operational condition. Sediment disposal
                 from site is to occur to the satisfaction of Noosa Council. Defects in erosion and sediment control
                 devices, such as sediment fences, are to be inspected and documented. Upon Inspection, the
                 Contractor is to determine whether the device should be replaced or repaired. Documentation is to
                 include how the damage was caused and what measures can be implemented to reduce the possibility
                 of repeat occurrences. Any damage to either permanent or temporary water quality control structures
                 or devices is to be immediately rectified at the contractor’s expense.
                 The effectiveness of the erosion and sediment control devices can be monitored by visual audits. All
                 ESC measures are to be inspected:

                     •    at least daily (when work is occurring on site) or weekly (when work is not occurring on site);
                     •    within 24 hours of expected rain; and



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Document Set ID: 23959990
Version: 1, Version Date: 23/07/2025