Reference Document - Slope Stability Certification Report (As Published) · MCU25/0022

                      •    Control the flow volume
                      •    Control the flow path
                      •    Reduce run off velocity
                 Many techniques are available to achieve these objectives. The following list provides some
                 common methods for Stormwater Management.
                      •    Vegetation Retention / Re‐Establishment: Plants provide a means of retarding
                           surface flow as well as acting as a natural filter. Where possible, natural vegetation
                           should be left undisturbed. Establishing vegetation cover in potential problem areas
                           (steep slopes, gullies etc.) will also assist in reducing erosion.
                      •    Surface Drains / Grassed Swales: Well grassed diversion drains provided above
                           exposed surfaces redirect water around erosion prone areas. These should be used in
                           conjunction with level spreading devices to disperse fast moving, concentrated surface
                           flows.
                      •    Level Spreaders: A level spreader typically consists of a coarse gravel filled trench
                           running parallel to the natural surface contours. This redistributes surface water and
                           allows concentrated flows to spread over a large area and decreasing the velocity.
                 Surface Erosion
                 Soils lost from land surfaces as a result of surface water run off not only removes valuable
                 topsoil from the area, but also result in siltation of downstream waterways when the sediments
                 settle. Loss of soil is usually the result of leaving bare surfaces exposed to the elements, or
                 from concentrated surface flows scouring the natural surface. Temporary measures can be
                 taken to control and contain sediment removal during construction such as:
                      •    Covering Stockpiles: Stockpiles of soil can be covered with plastic sheeting and re‐
                           spread when construction is completed.
                      •    Sediment Control Fencing: Hay bales or Hessian sacks supported between pickets
                           and placed across the paths of surface water can catch sediments for future re‐
                           spreading. Specialised sediment fencing is available for broad scale hillside scouring
                           protection.
                      •    Sediment Basin: A suitably sized earth basin may be constructed during the
                           development to capture turbid stormwater runoff, where the sediment is allowed to
                           settle before the cleaner water is pumped to a legal point of discharge. The sediment
                           should be regularly emptied during drier periods.
                 In general, it is recommended that all development on hillside areas should follow Good
                 Hillside Construction Practice recommended in the information sheets presented in Australian
                 Geomechanics Society “Practice Note Guidelines for Landslide Risk Management”,
                 Australian Geomechanics Vol 42 No. 1 March 2007. An extract is attached as Appendix E.




               193 Sankeys Rd Slope Stability Certification
                                                                                                      July 2023
                                                                  11
Document Set ID: 24390814
                  23591413
Version: 1, Version Date: 18/12/2025
                          28/02/2025