Supporting Technical Assessments

| Proposed Development – Surface Water Management | Stormwater Management Plan | 2210835-1190907474-109 | 21/06/2022 | 10 Sensitivity: General 4.5.5 Pond geometry The ponds will be shaped to be the most efficient volume storage within the existing site topography. Due to their location, they will require to be bunded above existing ground level in places. An access ramp will be provided to the forebay to allow for sediment removal. In accordance with TR2020-07, side slopes for the pond will be 1V:4H to create a maintainable slope and depth will be less than 2.0m with 0.3m freeboard (TR2020/07, Section 8.5.6.5). Attenuation calculations indicate the maximum water depth in the SFA detention pond under a 100-year, 24-hour storm event is approximately 1.4m. The pond volume by elevation is provided in Table 3. Table 6. SFA Detention Pond - Storage by Elevation Structure Storage Elevation (RL m) Total Volume (m3) 148 0 148.5 775 149 1700 149.5 2775 150 4000

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