REPS - Updated SWMP

TABLE 4.9: 10% AEP FLOWS – EXISTING VS MITIGATED SCENARIOS


 Scenario                          10% AEP

 Existing – Pipe Capacity (m3/s)   0.261

 Developed (m3/s)                  0.314

 Mitigated (m3/s)                  0.258

 Difference (m3/s)                 -0.003




4.3         Flows South to Starboard Avenue
From the development site there is approximately 0.8 ha of catchment (refer Figure 2.4) that would report south down Starboard Avenue in
events where the design capacity of the drainage network has been exceeded (i.e. minor design storm of 10% AEP). As mentioned earlier,
the original drainage design completed by TOD Consulting identified that capacity of the piped network reporting north from Catchment 1/3
(refer Figure 2.3) is 0.24m3/s in the 10% AEP. Flows in excess of this are considered to surcharge and report south to Starboard Avenue.

From this it is considered that the gap flow, being the difference between minor (10% AEP) and major storm (1% AEP), would report, as
overland flow, south down Starboard Avenue. Assessment of the pre-development flow reporting from this catchment, south, down
Starboard Avenue in the 1% AEP is approximately 0.37m3/s. The gap flow in the post-development scenario is 0.13m3/s (0.37 – 0.24m3/s),
which is less than the pre-development scenario. In the 10% AEP, the flow reporting south would be 0m3/s, hence, non-worsening is
achieved.



                                                                                                          Pipe Flow North
                                                                                                          (0.24m3/s)



                                                             0.8ha


                                                                                                             Gap Flow
                                                                                                             Report South




Figure 2.4: Catchment of Gap Flow Reporting South down Starboard Avenue




73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-2                                                                   18