Attachment G - Stormwater Quality Management plan

                                                                             Callaghan & Toth


5.0 FLOODING ASSESSMENT SUMMARY
The flood study for the site was undertaken by Hydrology & Water Management Consulting.
The results of the flood study and assessment are summarised below.

5.1      Existing Conditions

The site is bounded to the north by Cooroy Creek.

The site is subject to ponding of floodwaters from the adjacent watercourses and the Q100 year
ARI flood levels (i.e. 1% AEP event) (see Appendix A in Flood Study). The proposed
playground site is mostly below the Q100 year inundation line.

The flood assessment from Hydrology and Water reports on the hydrologic and hydraulic
performance of the site including upstream and downstream catchments.

5.2      Proposed Drainage System

The flood study determined the proposed level changes for the hinterland playground together
with the proposed new carpark areas on the northern side of Cooroy Creek from the existing
case to a developed case. The flood depths over the Q100, Q10 and Q2 year events was
comparable to the existing case for the site.

The flood study determined that the playground site needed to be lowered in some areas to
ensure that the proposed case was equivalent to the existing case.

As such the playground design has been amended by reducing some mounding across the site
and viewing platforms proposed in Cooroy Creek have been removed.




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2001 Hinterland Playground SWMP                                           February 2020