RFI - Stormwater Management Plan

(RIPs) in order to achieve no net reduction in rainwater infiltration. Notably
this approach sees higher than required rainfall intensities infiltrated without
RIPs overtopping in order to limit emergency overflows to ecological
restoration areas. Such an approach has been adopted on all previous Cape
Bouvard developments in the area.

RIPs are to be located at the south-western corner of the site within a
vegetated swale lined with appropriately remediated soils for stormwater
treatment. Splitter pits will be employed directly upstream of the swale with 3
month ARI flows directed to the swale surface for treatment and larger flows
routed directly into the RIPs.
Driveway and carpark areas will be passed through a GPT/oil arrester to
remove oils and hydrocarbons prior to infiltration.

Main roofed areas from buildings will drain to Rainwater Harvesting Tanks
with captured runoff utilized for landscape irrigation. Tank overflow will be
directed to the vegetated swale/RIPs. Runoff from all roofs and hardstand
areas will be piped to the RIPs for flow up to 100 year ARI.

Runoff from main landscaped areas will be intercepted and treated via
landscaped swales prior to collection in pits and pipes and discharge to small
localised RIPs (exact locations to be determined at OpWorks stage).

Major event flows surcharging from the RIPs in the unlikely event of RIP
failure would be directed westward via a stone pitched weir toward
ecological restoration areas as dispersed sheet flow. The rough nature of the
stone pitching will also provide an “energy dissipation” effect.



       4.1    Rapid Infiltration Pits (RIP’s)

       RIPs consist of a bottomless stormwater pit 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.

       RIPs will be subject to routine inspection and maintenance by the
       hotel’s maintenance team and such maintenance is critical to their
       ongoing function.

       (Refer Maintenance Schedule at Appendix C).

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A6769/22/SWMP/RevB – June
2023                                                                         Page 4 of 9
SH/PL
                       Brah101 Pty Ltd t/as ALTA PROJECTS