Site Based Stormwater Management Plan

5.1.3 Performance Objectives

The amount of runoff traversing and discharging from the site while under construction
should be kept to a minimum. This will restrict soil erosion and mobilisation of sediments
and pollutants through and off the site. Stormwater runoff at discharge points during the
construction phase shall comply with the objectives detailed in Table A in Appendix 2:
Stormwater Management Design Objectives, Part G, SPP (2017).

5.1.4 Control Measures

The following are typical treatment measures that should be implemented before the
commencement of any construction works. Detailed erosion and sediment control
procedures are to be based on the erosion and sediment control plans lodged at the
Operational Works phase.


Maintenance

Maintenance of erosion and control treatment measures (such as sediment fences) will be
undertaken if it is observed that they have not been properly installed or the capacity of the
measure falls below 75%.

Minimise Disturbed Areas

Only clear land which will be actively under construction in the near term (e.g. within the
next 3-6 months).

Stabilise Disturbed Areas

Provide temporary stabilisation of disturbed soils whenever active construction is not
occurring on a portion of the site. Provide permanent stabilisation during finish grade and
landscape the site.

Protect Slopes and Channels

Safely convey runoff from the top of the slope and stabilise temporary and permanent
channel crossings as quickly as possible and ensure that increases in runoff velocity caused
by the project do not erode the channel.

Diversions of Upslope Runoff

To prevent the contamination of clean runoff, upslope runoff should be diverted away from
areas of exposed soil. This may be achieved by installing tightly abutting sandbags, creating
a ‘sandbag perimeter bank’ to divert flow.




Site Based Stormwater Management Plan                                             Page 12 of 19
2123-SBSMP-01_Version 1.0 (October 2021)