11 Table 3: Dirty water diversion calculations and sizing details. Dirty water diversions Dirty water detail reference Catchment area 5% AEP rainfall depth (mm) Peak Flow (m3/s) Base Width (m) Slope (minimum) Minimum Design Flow Depth (mm) Including Minimum 300mm Freeboard DWD-1 <5ha 263mm 2.121 0.5 2% 350 650 DWD-2 5-10ha 263mm 4.243 0.5 2% 450 750 DWD-3 10-15ha 263mm 6.364 0.5 2% 500 800 Figure 4: Cross-section of a dirty water diversion. 3.3. Sediment Retention Ponds Multiple Sediment Retention Ponds (SRPs) are proposed to be constructed to capture sediment laden water during the earthworks associated with the TFS3 site establishment. The SRPs will be sized in respect to their contributing catchment area and slope steepness. - Where slopes are less than 10% and less than 200m in length, the SRP will be constructed with a minimum volume of 2% of the contributing catchment. - Where slopes are greater than 10% and/or more than 200m in length, the SRP will be constructed with a minimum volume of 3% of the contributing catchment. An additional volume of 10% will be provided in the forebay of each SRP. The SRPs will be located to allow access for removing sediment from the pond. Final design details will be provided as part of the updated SSESCP. A draft design for SRP-TSF3-01 is provided in Figure 5. Any pumping of sediment laden water required throughout the duration of the earthworks will be to a SRP forebay or to the Detention Pond for treatment prior to being discharged from the site.
RkJQdWJsaXNoZXIy MjE2NDg3