Att 3_CMP - Final

             Sediment fences should be used where sediment run-off occurs as reasonable uniform
             sheet flow on a slope. The preferable maximum catchment for sediment fences if 0.6ha
             per 100m of fence.

             Sediment fences should be located down slope of disturbances.

             In areas where it is impractical to bury the lower edge of the sediment fence, the lower
             200 mm (min) portion of the fabric should be placed on the ground upslope of the fence
             and buried under 100 mm (min) layer of coarse aggregate (20 mm – 40 mm).




                                        Figure 10: Sediment Fence

     5.4     Sediment Weirs
             Where larger catchments give rise to higher flows, which are concentrated in a narrow
             channel, more substantial devices than sediment fences will be provided.

             Sediment weirs may involve the use of:

             • Mesh and rock fill weirs
             • As an alternative, the use of rock check dams would be considered. Where rock is
             not readily available the use of demolition rubble or sandbags may be considered.

     5.5     Stockpile Management, Settlement Ponds and Sediment Basins
             A sediment basin is a temporary pond built on a construction site to capture eroded or
             disturbed soil that is washed off during rain stormed, and protect the water quality of a
             nearby system, river, lake, or bay. The sediment-laden soil settles in the pond before
             the runoff is discharged.

             Sediment basins are typically used on construction sites of 5 acres (20,000 m 2) or more,
             where there is sufficient room.

             If possible the permanent settlement structures will be constructed early, modified as
             necessary, and utilised during the construction as a component of the temporary
             drainage. Figure 11 shows a typical stockpile arrangement.




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