Att 3_CMP - Final

          Soil materials, sediment, and turbidity are categorised as ‘pollution’, as is any material that
          will change the physical, biological or chemical conditions of the water.

          The impacts of contaminated water on a receiving stream include the lowering of liveability
          conditions for the aquatic flora and fauna, and the silting of streams and drainage beds.

          The primary goal during construction is to minimise the length of time an area is disturbed.
          This will be achieved by sequencing of site-clearing and rehabilitation works to minimise
          exposure time. This will be done in conjunction with development of site-specific control
          structures.

    4. STORMWATER MANAGEMENT
          Stormwater will be managed to:

             •      Protect downstream water quality
             •      Minimise the potential for erosion and subsequent sedimentation
             •      Provide adequate and appropriate drainage and pollution control measures will be
                    installed to treat run-off from disturbed areas of the site
             •      Prevent soil materials and sediment from entering drainage systems

          Where practicable, these objectives will be implemented using the following principals:

             •      Stormwater will be diverted around the work areas.
             •      Run-off velocities will be minimised to reduce erosion.
             •      Isolate uncontaminated water from off-site.
             •      Treat contaminated water before it reaches waterways.
             •      Direct all run-off from disturbed site areas through control structures.

          It is recognised that there are many factors such as unexpected ground conditions, surface
          level deviations from design plans, ongoing changes to construction planning, etc, which
          may result in requirements for run-off controls to vary from original plans.

    4.1       DRAINAGE
                 Stormwater is either channelled around the site (i.e. via undisturbed surfaces) or within
                 the site to sediment control devices. The structure should be designed for their
                 designed flow velocity to resist erosion.

                 Particular attention should be given to diverting clean waters from outside the works
                 into the natural drainage system by the installation of diversion channels and perimeter
                 banks. The structures will be designed and placed on the site to minimise the
                 accumulation and velocity of run-off waters.

                 Drainage structure may include:

                    •       Grass drains, channels, and swales, which prevent scouring and promote
                            sediment retention.




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