20220089 Jirrima Cr SWMP

 STORMWATER QUALITY MANAGEMENT

     4.1. Construction Stormwater Management

          4.1.1 Erosion and Sediment Control Measures
During construction, it is necessary to manage stormwater run-off to avoid potential contamination of downstream
waterways from sediments and other pollutants from the site. A range of best practice sediment and erosion controls
should be implemented on the development to ensure negative impacts to the downstream receiving environment
are mitigated. The erosion and sediment control strategy should be based on the following key principles.

     •    Minimise the disturbed area – The clearing of land should be limited to areas actively under construction or
          those that will be in the near future (3 to 6 months)

     •    Stabilised disturbed areas – Once an area is no longer actively under construction, the exposed surfaces are
          to be stabilised through means such as control matting, grass seeding or turfing. Both temporary and
          permanent stabilisation need to be considered.

     •    Protection of channels – where water is concentrated through channels, drains or other flow paths these
          areas should be stabilised (e.g., check dams to limit velocity, geotextiles to limit erosion, concrete lining,
          etc.) with either temporary or permanent solutions.

     •    Maintenance – Regular inspections shall be carried out on all erosion and sediment controls, and where
          damage has been identified, or capacity of the device falls below 75%, prompt rectification of the defect
          shall be carried out to ensure the continued functioning of the controls.

A site-specific erosion and sediment control plan has been prepared for the development to achieve these
strategies. Erosion and sediment controls for the site nominated include:

     1. Sediment fencing along downstream of the work areas within the site to prevent sediment from leaving the
        construction area.

     2. A shakedown area is to be installed at the construction entry/exit to the proposed development area to
        minimise sediment being transported to and from the site.

     3. Ensuring any stockpiles and construction materials are located clear of overland flow paths and contained
        using sediment fencing downstream of these areas with upstream diversion berms to protect the stockpile.


          4.1.2 Erosion and Sediment Control Monitoring
The control measures described above must be maintained in an effective operational condition during the
construction works. Regular inspections should be carried out by the contractor and any defects in erosion and
sediment control devices specified for the site are to be remedied as soon as practicable. Any damage to either
temporary or permanent water quality control structures is to be immediately rectified at the contractor’s expense.
The inspection of the ESC devices is to be carried out as follows:

                1. Routine Inspection – is to be carried out daily while work is being carried out on site, or weekly
                   while works are not being carried out.
                2. Preventative inspection – to be carried out a maximum of 24 hours before rain is forecast.
                3. Reactive inspection – to be carried out within 18 hours of a rainfall event sufficient to mobilise
                   surface sediment on the site.

Documentation of these defects is to be carried out, recording the date the defect was identified, a description of
the defect, the cause of the defect and measures that can be implemented to reduce the likelihood of the defect
occurring in the future. Once the device has been repaired, the date of repair and the solution implemented



Project number 20220089                                                                                  Page 16 of 23
File 20220089 Jirrima Cr SWMP.docx, 2023-05-09 Revision 0


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