OPW20.0191 NC IR response

Figure 4 – Preliminary stabilisation works to the main drainage channel.

2.3
The staging of works has been shown on the attached Erosion and Sediment Control
Plans which are contained in Appendix A. Erosion and sediment control measures
are to remain in place and be inspected:
     • Daily when works are occurring on site
     • Weekly when works are not occurring on site
     • Within 24 hours of expected rainfall
     • Within 18 hours of a rainfall event of sufficient intensity and duration to cause
        runoff from the site.
2.4
To prevent runoff, upstream stormwater is proposed to be directed away from areas
that are not effectively stabilised. This approach will reduce the volume of water that
will need to be captured.

As part of stage 1, the majority of the stormwater runoff that falls internally to the site,
will be directed to the main drainage channel and to the proposed sedimentation
dams. The main drain will include rock check dams and has been vegetated to limit
the amount of sediment that is expected to enter the sediment dams. This will
increase the ease of managing any captured sediment.

The two sediment dams are estimated to have a capacity of 200m3 and 800m3
providing a total capacity of 1000m3. These dams are proposed to be Type D basins




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