1909-13367 SRA referral response approved docs

Erosion and sediment control plans shall be developed during detailed design phase and must be
continually maintained and amended as required to minimise environmental harm.

Erosion and sediment control plans are based on three sets of control measures:
1.        Drainage control

2.        Erosion control

3.        Sediment control
These control measures must be maintained in an effective operational condition. Sediment disposal
from site is to occur to the satisfaction of NSC. Defects in erosion and sediment control devices, such
as sediment fences and baskets, are to be inspected and documented. Upon Inspection, the Contractor
is to determine whether the device should be replaced or repaired. Documentation is to include how the
damage (if applicable) was caused and what measures can be implemented to reduce the possibility
of repeat occurrences. Any damage to either permanent or temporary water quality control structures
or devices is to be immediately rectified at the contractor’s expense.

The effectiveness of the erosion and sediment control devices can be monitored by visual audits. All
ESC measures are to be inspected:

         at least daily (when work is occurring on site) or weekly (when work is not occurring on site)

         within 24 hours of expected rain

      within 18 hours of a rainfall event (i.e. an event of sufficient intensity and duration to mobilise
sediment on site)

Drainage paths are to be inspected to ensure the sediment fences are not being bypassed as a result
of soil erosion.

Sediment laden run-off shall be prevented from entering neighbouring properties. This shall be achieved
by landscaping disturbed areas immediately and prior to a rainfall event.

An erosion hazard assessment has been conducted in accordance with IECA.

The proposed development received an erosion hazard score of 23. This score exceeds the trigger
value of 17. Additionally, the proposed site meets or exceeds the trigger value for area of disturbance
and waterway disturbance due to the construction of the bridge across the existing natural channel. As
part of the detailed design phase of the proposed development a detailed ESCP shall be prepared by
a suitably qualified consultant. See Appendix AA for the completed erosion hazard assessment form.

4.3.2 M aint en an ce and M onit o ri ng R equ ir em ent s

Periodic maintenance and monitoring of stormwater devices proposed in this report is crucial to ensure
effective operation and design life.

Inspect field inlet grates, pits and underground pipes for blockage or damage at least 6 monthly or after
significant rainfall event. Bioretention basins should be inspected for scour of filter medium, death of
plants, collapse of filter medium and ponding at least 3 monthly or after significant rainfall event. Results
of the initial 12 months maintenance program shall be used to determine future maintenance intervals.
Refer manufactures maintenance and monitoring methodology for specific details.




                                       Stormwater Management Report                                       16
S19-007                                  122 & 144 Myall St, Cooroy