RFI - Att 4 - Stwtr Mngmt Plan

                                                                                                                          ingeniir

Method Calculations provides estimates of the current and developed flows for both the development site
(23 Coral Tree Avenue) and the neighbouring site (28 Banksia Avenue), although the flows rates presented
are considered conservative as the soils in this area are known to have infiltration rates of 125mm/hour or
better.

In accordance with IPWEAQ standard drawing RS-081 the site achieves 25L/s per discharge point for a 5% AEP
noting that RS-081 is for roof water kerb adapters and typical eaves gutters having a design capacity for the
5% AEP event.

Site discharge rates are only expected to have a minor increase on the existing site discharge rates and
provide an improved drainage connection to the formal infrastructure being Coral Tree Avenue as the site
currently does not have any formalised discharge to the street.

The site has negligible increase in flows of only 2L/s in 1% AEP flows to the kerb so is not considered capable
producing a worsening of flows as there is minimal change to the existing catchment characteristics.


7.    FLOODING
The site is in an elevated position locally and regionally and is not known to have any flood risk. A review of
the Noosa Shire Council’s Intramaps (accessed 19/05/2022) indicates that the site is not affected by any
known flood or storm tide studies. Refer Plate 3 for an excerpt of the Council mapping.




            Plate 3: Noosa Shire Council Flood Hazard Area/Defined Flood Extent in the vicinity of the site (Site highlighted)




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