Stormwater Report

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

    •   drainage control;

    •   erosion control; and
    •   sediment control.

These control measures must be maintained in an effective operational condition. Sediment disposal
from site is to occur to the satisfaction of Noosa Council. Defects in erosion and sediment control
devices, such as sediment fences, 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 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; and

    •   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 runoff shall be prevented from entering neighbouring properties. This shall be achieved
by landscaping disturbed areas immediately and prior to a rainfall event.

The proposed development has scored a 13 on the IECA erosion hazard assessment with no trigger
score values exceeded (refer Appendix A for details). Further details of proposed on site erosion and
sediment control measures will be required at the detailed design phase of the development.
4.2.3 Ma int en an ce and M o nit o ri ng Re qui r 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. The filter baskets shall be inspected and maintained preferably by the
manufacturer to avoid damage to units and to ensure adequate cleaning and record keeping. For the
first 12 months routine inspections of filter baskets shall be carried out monthly with routine clean out
at alternate months. 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.

Maintenance of ESC measures must occur in accordance with Table 5.

Table 5 - ESC maintenance requirements.

        ESC Measure                  Maintenance Trigger              Timeframe for Completion
                                                                           of Maintenance

 Sediment basins               When settled sediment exceeds         Within 7 days of the
                               the volume of the sediment            inspection.
                               storage zone


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