Stormwater Management Plan -OPW (A) · OPW25/0042

Major event flows surcharging from the RIPs in the unlikely event of RIC
failure would be directed eastward via a stone pitched weir toward existing
vegetated swale areas and ultimately Noosa Inlet (legal point of discharge) as
dispersed sheet flow.

The rough nature of the stone pitching will also provide an “energy
dissipation” effect.

All grated stormwater pits around the site will be fitted with litter baskets to
intercept gross pollutants.


6.1RAPID INFILTRATION PITS/RAPID INFILTRATION CULVERTS
(RIP/RICS)

RIPs/RICs consist of a bottomless stormwater pit/culvert which promotes
infiltration through its base.

Crushed rock and multiple layers of geofabric and “sacrificial sand” are
installed at the base of the RIP to protect against clogging of dune sands
below.

Refer engineering drawings at Appendix A for RIP/RIC details.



6.2     RIP/RIC INFILTRATION CAPACITIES


6.2.1 PROTOTYPE RIP TESTING 2003

Alta Projects Engineers (formally TATE) were involved in formulation of the
over-arching development approval document and EMP1.

Such involvement included construction of a prototype RIP on the Settlers
Cove site consisting of a 225mm diameter pipe buried vertically in clean
white sand and with a geofabric filter across the base.

A test site was chosen near the end of Serenity Close at the time (circa 2003)
roughly coinciding with the existing stormwater/sewer easement through the
site.
By inspection it is inferred that 2003 prototype testing would likely to have
been carried out at an approximate level of RL18-20m AHD, with a
corresponding estimated base RL of 15-17m AHD for a 3m length of pipe.
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A6769/25/SWMP/Rev OpW(A) – Feb 2025
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SH/PL
                         Brah101 Pty Ltd t/as ALTA PROJECTS