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DEVTEX NOMINEES
73 Eumundi - Noosa Road, Noosaville
Stormwater Management Plan
BBNE00529_0002_0001-REP-001-0
25 SEPTEMBER 2024
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0
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Full text of sections 2 to 25 (of 34)
Section 2
DISCLAIMER This Report has been prepared on behalf of and for the exclusive use of DEVTEX NOMINEES and is subject to and issued in accordance with DEVTEX NOMINEES instruction to Engeny Australia Pty Ltd (Engeny). The content of this Report was based on previous information and studies supplied by DEVTEX NOMINEES. Engeny accepts no liability or responsibility whatsoever for it in respect of any use of or reliance upon this Report by any third party. Copying this Report without the permission of DEVTEX NOMINEES or Engeny is not permitted. Rev Date Description Author Reviewer Project Mgr. Approver 0 25/09/2024 Client Issue Adeeba Ayaz Brendon Bolt Brendon Bolt Kelsey Mundt Signatures: 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 ii
Section 3
CONTENTS
1. Introduction 1
1.1 Project Purpose and Scope 1
1.2 Site Characteristics 1
1.3 Project Data and Guidelines 3
1.4 Performance Criteria 3
1.5 Previous Approval 3
2. Stormwater Quality Management 4
2.1 Overview 4
2.2 Operational Phase 4
2.3 Model Development 4
2.3.1 Catchments 4
2.3.2 Climate Data 5
2.3.3 Modelling Parameters 5
2.4 Treatment System 7
2.4.1 Treatment Train Sizing 7
2.5 Water Quality Model Results 8
2.6 Treatment Train Operation and Maintenance 9
2.6.1 Construction & Establishment 9
3. Stormwater Quantity Management 10
3.1.1 Existing Scenario 10
3.1.2 Developed Scenario (unmitigated) 11
3.1.3 Mitigation Scenario 13
4. Conclusion 14
5. QUALIFICATIONS 15
Appendices
Appendix A: Proposed Site Layout Plan 16
Appendix B: Preliminary Engineering Design Plans 17
Appendix C: WBNM Results Summary 18
Tables
Table 2.1: Water Quality Objectives .................................................................................................................................................................... 4
Table 2.2: Treated Catchment Properties ............................................................................................................................................................ 4
Table 2.3: Rainfall-Runoff Parameters ................................................................................................................................................................. 5
Table 2.4: Pollutant Export Parameters ............................................................................................................................................................... 6
Table 2.5: Bioretention Parameters..................................................................................................................................................................... 7
Table 2.6: MUSIC Model Results .......................................................................................................................................................................... 8
Table 3.1:WBNM Sub-Catchment Fraction Impervious Values - Existing Scenario ........................................................................................... 11
Table 3.2: Existing Peak Flows ........................................................................................................................................................................... 11
Table 3.3:WBNM Sub-Catchment Fraction Impervious Values - Developed Scenario ...................................................................................... 11
Table 3.4: Peak Discharge Comparison – Existing Vs Developed Sceanrio ........................................................................................................ 12
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 iii
Section 4
Table 3.4: Elevation-Storage Data for Approved / Constructed Detention Basin .............................................................................................. 13 Table 3.4: Peak Discharge Comparison – Existing vs Mitigated Scenarios ......................................................................................................... 13 Figures Figure 1.1: Locality Plan ....................................................................................................................................................................................... 1 Figure 1.2: New Townhouse Locality ................................................................................................................................................................... 2 Figure 2.1: Stormwater Quality Catchment Plan ................................................................................................................................................. 5 Figure 2.2: Typical Conventional Bioretention Filter Section (Water by Design, 2014) ....................................................................................... 7 Figure 2.3: Music Model Arrangement for Developed Case ................................................................................................................................ 8 Figure 2.1: Existing Scenario Catchment Plan .................................................................................................................................................... 10 Figure 2.2: Developed Scenario Catchment Plan ............................................................................................................................................... 12 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 iv
Section 5
1. INTRODUCTION
Engeny Australia Pty Ltd (Engeny) have been engaged by Devtex Nominees Pty Ltd to prepare an update to an approved Stormwater
Management Plan (SMP) to incorporate a townhouse development within a portion of the approved site (located on approved lots 1, 2, 3,
48, 49 and 50) at 73 Eumundi-Noosa Road, Noosaville (the Site). The original Reconfiguration of Lot (ROL) application (23686 DA) was
approved following an appeal in the Planning and Environment Court (Appeal No: 118 of 2006). From which an Operational Works application
was approved (Ref: OPW15/0133 dated 6 March 2017). As part of the OPW, a SMP was prepared by AquaIntel (02/09/2016 – revision B).
1.1 Project Purpose and Scope
The purpose of this SMP is to identify if the approved / constructed stormwater treatment measures can manage the new townhouse
configuration located within the approved development to achieve the requirements of the Noosa Shire Council (NSC) Planning Scheme
"Water Quality and Drainage Code”. The scope of the project has included the following:
• Assessment of the Site’s stormwater quantity and stormwater quality management based on the approved and constructed bioretention
and detention basins.
• Confirmation that the existing detention basin can manage stormwater quantity runoff from the Site based on the updated layout.
• Confirmation that the existing bioretention basin can still achieve the required Water Quality Objectives (WQO’s) for the Site based on
the updated layout.
• Collation of findings in a consolidated Stormwater Management Plan (SMP).
1.2 Site Characteristics
The Site has an area of 4.65 ha, with 0.5 ha being utilised for the proposed townhouse development. The pre-development site was largely
cleared with sporadic trees at rear. The Site grades from the west to east and connects into a culvert under Sands Avenue. Site elevations
range from 2.0 to 12.0 m AHD. There is a minor external catchment which extends to the west of the site up to Eumundi-Noosa Road. The
proposed townhouse layout and associated engineering drawings are provided in Appendix A and Appendix B, respectively. The location of
the Site is shown in below Figure 1.1, with the post-development layout shown in Figure 1.2.
SITE
Figure 1.1: Locality Plan
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 1
Section 6
1.3 Project Data and Guidelines
The following data has been utilised for this assessment:
• Site plans prepared by Blackwood Architects (dated 13/09/2024).
• Design inputs for hydrologic and hydraulic modelling from the Australian Rainfall and Runoff Data Hub.
• Rainfall and Meteorological Data by Australian Bureau of Meteorology (BoM).
• Aerial LiDAR data of the ANZLIC Committee on Surveys and Mapping (ELVIS, https://elevation.fsdf.org.au/).
The guidelines, standards, and codes considered during the assessment were as follows:
• Noosa Council Planning Scheme 2020.
• Planning act 2016 and the associated State Planning Policy (DILGP, 2017).
• MUSIC Modelling Guidelines (Water by Design, 2018).
• Queensland Urban Drainage Manual 2017 (QUDM).
• Australian Rainfall and Runoff 2019 (ARR) 2019 (Ball, et al, 2019).
Reference documents relevant to the assessment are:
• NSC OPW Approval (ref: OPW15/0133 dated 6 March 2017).
1.4 Performance Criteria
Several objectives have been adopted for the development with respect to the management of stormwater quality and quantity:
• Stormwater Quality:
– 80% reduction in total suspended solids.
– 60% reduction in total phosphorous.
– 45% reduction in total nitrogen.
– 90% reduction in gross pollutants.
• Stormwater Quantity:
– No actionable nuisance caused by changes in stormwater quantity.
1.5 Previous Approval
As mentioned earlier, the original reconfiguration application (23686 DA) was approved following an appeal in the Planning and Environment
Court (Appeal No: 118 of 2006). Following this, an Operational Works (OW) application was approved (Ref: OPW15/0133 dated 6 March
2017). As part of the OW application a SMP (prepared by AquaIntel dated 2 September 2016 – Revision B) was approved in support of the
OW approval. As of the approved SMP, the following was design and constructed.
• Bioretention Basin – 400m2 filter area with 0.3 m extended detention depth.
• Detention Basin – Storage Volume of 1,018 m3.
This updated assessment for the townhouse (located on approved lots 1, 2, 3, 48, 49 and 50) will aim to utilise the existing stormwater
bioretention and detention basin in the assessment to confirm the objectives are still maintained.
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 3
Section 7
1.3 Project Data and Guidelines
The following data has been utilised for this assessment:
• Site plans prepared by Valentine Building Design (dated 10/03/2022).
• Design inputs for hydrologic and hydraulic modelling from the Australian Rainfall and Runoff Data Hub.
• Rainfall and Meteorological Data by Australian Bureau of Meteorology (BoM).
• Aerial LiDAR data of the ANZLIC Committee on Surveys and Mapping (ELVIS, https://elevation.fsdf.org.au/).
The guidelines, standards, and codes considered during the assessment were as follows:
• Noosa Council Planning Scheme 2020.
• Planning act 2016 and the associated State Planning Policy (DILGP, 2017).
• MUSIC Modelling Guidelines (Water by Design, 2018).
• Queensland Urban Drainage Manual 2017 (QUDM).
• Australian Rainfall and Runoff 2019 (ARR) 2019 (Ball, et al, 2019).
Reference documents relevant to the assessment are:
• NSC OPW Approval (ref: OPW15/0133 dated 6 March 2017).
1.4 Performance Criteria
Several objectives have been adopted for the development with respect to the management of stormwater quality and quantity:
• Stormwater Quality:
– 80% reduction in total suspended solids.
– 60% reduction in total phosphorous.
– 45% reduction in total nitrogen.
– 90% reduction in gross pollutants.
• Stormwater Quantity:
– No actionable nuisance caused by changes in stormwater quantity.
1.5 Previous Approval
As mentioned earlier, the original reconfiguration application (23686 DA) was approved following an appeal in the Planning and Environment
Court (Appeal No: 118 of 2006). Following this, an Operational Works (OW) application was approved (Ref: OPW15/0133 dated 6 March
2017). As part of the OW application a SMP (prepared by AquaIntel dated 2 September 2016 – Revision B) was approved in support of the
OW approval. As of the approved SMP, the following was design and constructed.
• Bioretention Basin – 400m2 filter area with 0.3 m extended detention depth.
• Detention Basin – Storage Volume of 1,018 m3.
This updated assessment for the townhouse (located on approved lots 1, 2, 3, 48, 49 and 50) will aim to utilise the existing stormwater
bioretention and detention basin in the assessment to confirm the objectives are still maintained.
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 3
Section 8
2. STORMWATER QUALITY MANAGEMENT 2.1 Overview This proposed development was originally approved for 50 low density residential lots and associated new road. Since the initial development, a portion of the Site – 6 lots (refer Figure 1.2), is proposed to be converted to a townhouse site consisting of 11 dwellings. This stormwater quality assessment proposes to confirm the existing bioretention constructed as part of the original development (OPW15/0133) still achieves load-based Water Quality Objectives (WQO’s) for the Site with the inclusion of the new townhouse area. 2.2 Operational Phase The WQO’s stipulated in the State Planning Policy – July 2017 for the South-East Queensland region will be adopted for the Site. The NSC Planning Scheme provides stormwater management design objectives for the operational phase of developments. The applicable Water Quality Objectives (WQO’s) for the Site are shown in Table 2.1. TABLE 2.1: WATER QUALITY OBJECTIVES Pollutant Minimum Load Reduction Target (%) Total Suspended Solids (TSS) 80 Total Phosphorus (TP) 60 Total Nitrogen (TN) 45 Gross Pollutants (GP) 90 2.3 Model Development 2.3.1 Catchments The representation of the post-development catchments (approved development and new townhouse) has been split into three catchment source nodes, being road, roof and ground. The development site area then reports to a bioretention basin. Catchment properties have been summarized in Table 2.2Error! Reference source not found. and a catchment plan shown in Figure 2.1. TABLE 2.2: TREATED CATCHMENT PROPERTIES Land Use Approved Development (ha) Bypass (ha) New Townhouse (ha) Total Impervious (%) Roof 0.766 0.060 0.239 100 Road / Hardstand 0.920 - 0.080 100 Ground 1.905 0.147 0.187 20 Park 0.348 - - 0 Total 3.936 0.207 0.506 - 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 4
Section 9
Figure 2.1: Stormwater Quality Catchment Plan 2.3.2 Climate Data Climate data for the catchment was sourced from the Bureau of Meteorology (BoM). Rainfall pluviograph data was obtained from the Corooy gauge for the ten (10) years between 1/1/1973 and 31/12/1983 at six-minute intervals. 2.3.3 Modelling Parameters The MUSIC water quality model (2018 – Version 3) has been used to represent the proposed development. Table 2.3 and Table 2.4 highlight the source node parameters from “MUSIC Modelling Guidelines” (Water by Design, 2010) that were applied in the MUSIC model. TABLE 2.3: RAINFALL-RUNOFF PARAMETERS Parameter Source Node Source Node Land Use Residential Rural Residential (Park) Rainfall Threshold (mm) 1 1 Soil Storage Capacity (mm) 500 98 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 5
Section 10
Parameter Source Node Source Node
Initial Storage (% capacity) 10 10
Field Capacity (mm) 200 80
Infiltration Capacity Coefficient A 211 84
Infiltration Capacity Exponent B 5 3.3
Initial Depth (mm) 50 50
Daily Recharge Rate (%) 28 100
Daily Baseflow Rate (%) 27 22
Daily Deep Seepage Rate (%) 0 0
TABLE 2.4: POLLUTANT EXPORT PARAMETERS
Land Use Flow Type TSS Log Values TP Log Values TN Log Values
MEAN ST. DEV. MEAN ST. DEV. MEAN ST. DEV.
Baseflow - - - - - -
Roof
Stormflow 1.30 0.39 -0.89 0.31 0.26 0.23
Baseflow 1.00 0.34 -0.97 0.31 0.20 0.20
Road
Stormflow 2.43 0.39 -0.30 0.31 0.26 0.23
Baseflow 1.00 0.34 -0.97 0.31 0.20 0.20
Ground
Stormflow 2.18 0.39 -0.47 0.31 0.26 0.23
Baseflow 0.53 0.24 -1.54 0.38 -0.52 0.39
Rural Res
Stormflow 2.26 0.51 -0.56 0.28 0.32 0.30
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 6
Section 11
2.4 Treatment System The approved / constructed bioretention basin is proposed to treat the stormwater runoff from the Site, which includes the proposed townhouse site. The location of the bioretention system is co-located with the detention basin and will be located in the north-east corner of the site, just upstream of Sands Avenue (site outlet). An indicative footprint area has been set aside to the north of the proposed car parking area. A standard bioretention filter media configuration is proposed, with a typical section detail shown in Figure 2.2. Figure 2.2: Typical Conventional Bioretention Filter Section (Water by Design, 2014) 2.4.1 Treatment Train Sizing The bioretention basin has been modelled in MUSIC in accordance with the Water by Design MUSIC Modelling Guidelines. The modelled bioretention system properties are summarized in Table 2.5. The MUSIC model layout can be seen in Figure 2.3. TABLE 2.5: BIORETENTION PARAMETERS Parameter Value Extended Detention Depth (m) 0.3 Storage Surface Area (m2) 575 Filter Media Area (m2) 403 Unlined Filter Media Perimeter (m) 0 Saturated Hydraulic Conductivity (mm/hr) 200 Filter Depth (m) 0.5 TN Content of Filter Media (mg/kg) 400 Orthophosphate Content of Filter Media (mg/kg) 30 Exfiltration Rate (mm/hr) 0 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 7
Section 12
Figure 2.3: Music Model Arrangement for Developed Case
2.5 Water Quality Model Results
The results of the MUSIC model have been summarised in Table 2.6. The results of the MUSIC modelling indicate that the load-based
reduction targets have been achieved with the proposed treatment train. As such, the proposed treatment train will be adopted for the Site.
TABLE 2.6: MUSIC MODEL RESULTS
Parameter Unmitigated Mitigated Reduction Target Compliance
(kg/yr) (kg/yr) Achieved (%) Reduction (%) Achieved
Total Suspended Solids (TSS) 7760 1310 83.1 80 ✓
Total Phosphorus (TP) 14.4 3.53 75.5 60 ✓
Total Nitrogen (TN) 94.9 43.5 54.2 45 ✓
Gross Pollutants (GP) 7760 1310 83.1 90 ✓
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 8
Section 13
2.6 Treatment Train Operation and Maintenance
In the context of development Sites and associated construction and building works, delivering bioretention basins and establishing
vegetation can be challenging. Therefore, bioretention basins require a careful construction and establishment approach to ensure the basins
are formed in accordance with the design intent. The following sections outline a recommended staged construction and establishment
methodology for bioretention basins as outlined within Healthy Waterways Technical Design Guidelines.
2.6.1 Construction & Establishment
The following is a proposed staged construction and establishment method:
2.6.1.1 Functional Installation
Construction of the functional elements of the bioretention basin will occur at the end of civil works construction along with the installation
of temporary protective measures. During the building phase, the protection will consist of a suitable geofabric covered with shallow topsoil
(e.g. 25 mm) and sacrificial turf layer until 80-90% of the building in the catchment is complete.
This is in alignment with Option 1 of the Construction and Establishment Guidelines (Water by Design, 2010). This guideline should be referred
to for the step-by-step sequence and sign-off forms.
2.6.1.2 Erosion and Sediment Control
An Erosion and Sediment Control program and plan will be prepared for the construction phase of the development. This will be completed
for the Site in the detailed design phase and is to be kept on Site and implemented for the duration of the construction phase.
2.6.1.3 Operational Establishment
At completion of the building phase, removal of any temporary protective measures along with accumulated sediment and the system
planted in accordance with the design planting schedule.
Vegetation establishment will be aided based on the following controls:
• Weed control:
Adopting high planting densities and if necessary, applying a suitable biodegradable erosion control matting to the batters will help to
combat weed invasion and reduce labour intensive maintenance requirements. A heavy application of seedless hydro-mulch can also
provide short term erosion and weed control. No matting or hydro-mulch is to be applied to the surface of the bioretention basin
following the construction phase, as this will hinder filtration of stormwater through the filter media.
• Watering:
Regular watering of bioretention basin vegetation is essential for successful establishment and healthy growth. The frequency of watering
to achieve the successful plant establishment is dependent upon rainfall, maturity of planting stock and the water holding capacity of
the soil. The following watering program is generally adequate but should be adjusted to suit the Site conditions:
Week 1-2 3 visits/week.
Week 3-6 2 visits/week.
Week 7-12 1 visit/week.
After this initial 3-month period, watering may still be required, particularly during the first winter. Watering requirements to sustain healthy
vegetation should be determined during ongoing maintenance Site visits.
2.6.1.4 Maintenance
The bioretention system will be maintained by the Council owner, who as the asset custodian, will be responsible for the on-going
maintenance of the water quality device. Operations and maintenance should be conducted in accordance with the Maintaining Vegetated
Stormwater Assets (Feb 2012) guideline.
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 9
Section 14
3. STORMWATER QUANTITY
MANAGEMENT
This section assesses the potential impact that the proposed new townhouse development will have on peak flows discharging to the existing
detention basin approved and constructed as part of the original approval (OPW15/0133).
Hydrologic modelling of the catchment has been carried out using WBNM software developed jointly by the University of Wollongong, Rienco
Consulting and Balance R&D. The 2019 version has been used for this investigation, with ARR2019 hydrology.
Modelling has been carried out for the 63%, 50%, 20%, 10%, 5%, 2% and 1% AEP storm events. The following scenarios have been
investigated:
• Existing Scenario.
• Developed Scenario.
• Mitigated Scenario.
3.1.1 Existing Scenario
The Existing Scenario catchment boundaries and parameters are consistent with the approved report (AquaIntel, 2016). The only changes
made to this scenario was to update the hydrology model to utilise the ARR2019 methodology and update the losses to align with the Noosa
River Flood Study (2017). The existing catchment plan is shown in Figure 2.1, with the proposed townhouse development located in SUBB.
The existing scenario sub-catchment areas and fraction impervious values for each sub-catchment are tabulated below in Table 3.1.
Figure 2.1: Existing Scenario Catchment Plan
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 10
Section 15
TABLE 3.1:WBNM SUB-CATCHMENT FRACTION IMPERVIOUS VALUES – EXISTING SCENARIO
WBNM Sub-Catchment Area (ha) Impervious (%)
SUBA 1.43 50
SUBB 4.29 10
Total 5.71
The catchment lag parameter adopted was 1.6, which is within the accepted range of values provided in the WBNM technical reference
manual. Rainfall loss rates adopted are consistent with those from the Noosa River Flood Study (2017) and are an initial and continuing loss
of 15 mm and 2.5 mm/h for pervious surfaces respectively, and 0 mm and 0 mm for impervious surfaces. Modelling has been completed for
a range of standard design storm events ranging from the 63.2% AEP to the 1% AEP event, with durations ranging from 10 minutes to 3
hours. Peak flows tabulated in this report represent the peak values extracted from this range of storm events.
TABLE 3.2: EXISTING SCENARIO PEAK FLOWS
63% AEP 50% AEP 20% AEP 10% AEP 5% AEP 2% AEP 1% AEP
WBNM (m3/s) 0.60 0.72 1.11 1.41 1.68 1.99 2.23
3.1.2 Developed Scenario (unmitigated)
For the Developed Scenario (unmitigated) the approved development was represented along with the new townhouse area proposed in the
south-west corner of the development. The development was represented within the WBNM model by adjusting the site sub-catchments
and the fractions impervious values. The catchment parameters applied in the Developed Scenario are provided in Table 3.4, with the
approved development represented as low density residential (50% imp), townhouse site (90% imp) and park area (0% imp).
The Developed Scenario catchment plan is shown in Figure 2.2
TABLE 3.3: WBNM SUB-CATCHMENT FRACTION IMPERVIOUS VALUES – DEVELOPED SCENARIO
WBNM Sub-Catchment Area (ha) Impervious (%)
SUBA 1.430 50
SUBB 4.408 50.7
SUBC 0.140 50
Total 5.978 -
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 11
Section 16
Figure 2.2: Developed Scenario Catchment Plan
A comparison of the Existing and Developed scenario peak flow shows the Site would result in an increase in peak flows if the detention basin
was not constructed, which is in line with outcomes of the approved SMP (AquaIntel, 2016).
TABLE 3.4: PEAK DISCHARGE COMPARISON – EXISTING VS DEVELOPED SCEANRIO
63% AEP 50% AEP 20% AEP 10% AEP 5% AEP 2% AEP 1% AEP
Existing (m3/s) 0.60 0.72 1.11 1.41 1.68 1.99 2.23
Developed (m3/s) 0.83 0.98 1.47 1.79 2.10 2.45 2.74
Difference (m3/s) 0.22 0.26 0.36 0.38 0.42 0.46 0.51
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 12
Section 17
3.1.3 Mitigation Scenario
For the Mitigation Scenario, the only update made to the Developed Scenario model was to represent the approved / constructed detention
basin. A summary of the elevation-storage data for the detention basin is provided in Table 3.5 with a summary of the outlet configuration
and key details provided below:
• Outlet Summary:
– Pipe 1 = 1 x 225mm at RL1.56m.
– Pipe 2 = 900 x 900mm culvert at RL1.56m.
– Weir = 5m at RL2.72m.
TABLE 3.5: ELEVATION-STORAGE DATA FOR APPROVED / CONSTRUCTED DETENTION BASIN
Elevation (m RL) Volume (m3)
1.56 0
1.7 81
1.9 206
2.1 344
2.3 494
2.5 659
2.7 841
2.8 1019
A comparison of the existing and mitigated peak flows at the Site outlet is presented in Table 3.6. The results show that a minor increase in
peak flows is expected in the smaller events (<10% AEP) and the 1% AEP, with reductions in the 5% and 2% AEP events. As the catchment
details have not changed significantly between the approved SMP and this update, it is considered the minor increases are a result of the
change in the hydrologic method from ARR1987 to ARR2019 and the change to the losses. As such, it is considered that these minor increases
would not result in actionable nuisance, and the outcome remains consistent with the approved SMP. Further to this, the Site’s bioretention
system will provide some additional detention in the smaller flood events to help in managing this further.
TABLE 3.6: PEAK DISCHARGE COMPARISON – EXISTING VS MITIGATED SCENARIOS
Scenario 63.2% AEP 50% AEP 20% AEP 10% AEP 5% AEP 2% AEP 1% AEP
Existing (m3/s) 0.61 0.72 1.11 1.41 1.68 1.99 2.23
Mitigated (m3/s) 0.65 0.77 1.16 1.42 1.64 1.92 2.27
Difference (m3/s) 0.05 0.05 0.05 0.01 -0.04 -0.07 0.03
A full summary of peak flow results is presented in Appendix C.
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 13
Section 18
4. CONCLUSION Engeny have completed this SMP for Devtex Nominees Pty Ltd to represent the proposed townhouse development to be incorporated into a portion (located on approved lots 1, 2, 3, 48, 49 and 50) of a previously approved reconfiguration of Lot (Planning and Environment Court (Appeal No: 118 of 2006) and Operational Works application (Ref: OPW15/0133 dated 6 March 2017)). The approved roads, lots and detention / bioretention basins have been constructed as part of the Operational Works approval. This assessment has been completed to determine if the approved / constructed detention and bioretention basin can manage the new townhouse site within the approved developed. The following summarises the findings from the Stormwater Management Plan for the proposed development at 73 Eumundi Noosa Road, Noosaville. Stormwater Quality The existing bioretention basin (403m2 filter surface) is suitable to achieve the Water Quality Objectives outlined in the NSC Planning Scheme. Details of the water quality modelling and sizing of the treatment train are summarised in Section 2. Stormwater Quantity The existing detention basin (1,019 m3 storage volume) is suitable to provide mitigation for the stormwater quantity flows, with only minor increases noted in peak flows in the smaller events (<10% AEP) and the 1% AEP, with reductions in the 5% and 2% AEP events. As the catchment details have not significantly changed between the approved SMP and this assessment, it is considered the minor increases are a result of the change in the hydrologic method from ARR1987 to ARR2019 and the updated catchment losses. As such it is considered that these minor increases would not result in actionable nuisance, and the outcome remains consistent with the approved SMP. Details of the water quantity modelling is summarised in Section 3. Preliminary Engineering Plans Preliminary engineering plans detailing the stormwater management arrangement is provided in Appendix B. 73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 14
Section 19
5. QUALIFICATIONS
(a) In preparing this document, including all relevant calculation, and modelling, Engeny Australia Pty Ltd (Engeny) has exercised the degree
of skill, care and diligence normally exercised by members of the engineering profession and has acted in accordance with accepted
practices of engineering principles.
(b) Engeny has used reasonable endeavours to inform itself of the parameters and requirements of the project and has taken reasonable
steps to ensure that the works and document is as accurate and comprehensive as possible given the information upon which it has
been based including information that may have been provided or obtained by any third party or external sources which has not been
independently verified.
(c) Engeny reserves the right to review and amend any aspect of the works performed including any opinions and recommendations from
the works included or referred to in the works if:
(i) Additional sources of information not presently available (for whatever reason) are provided or become known to Engeny; or
(ii) Engeny considers it prudent to revise any aspect of the works in light of any information which becomes known to it after the
date of submission.
(d) Engeny does not give any warranty nor accept any liability in relation to the completeness or accuracy of the works, which may be
inherently reliant upon the completeness and accuracy of the input data and the agreed scope of works. All limitations of liability shall
apply for the benefit of the employees, agents, and representatives of Engeny to the same extent that they apply for the benefit of
Engeny.
(e) This document is for the use of the party to whom it is addressed and for no other persons. No responsibility is accepted to any third
party for the whole or part of the contents of this Report.
(f) If any claim or demand is made by any person against Engeny on the basis of detriment sustained or alleged to have been sustained as
a result of reliance upon the Report or information therein, Engeny will rely upon this provision as a defence to any such claim or
demand.
(g) This Report does not provide legal advice.
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 15
Section 20
APPENDIX A: PROPOSED SITE
LAYOUT PLAN
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 16
Section 21
Sewer MH:*Plotted from records*
IL: 10.20 (from records) Sewer MH:*Plotted from records*
Type: 150 PVC IL: 5.34 (from records)
Type: 150 PVC
MH MH
EMT ASP305303 EMT DSP305303 EMT ESP305303
Sewer MH:*Plotted from records*
IL: 5.22 (from records)
Type: 150 PVC
EMT YSP2
98783
Sewer MH:*Plotted from records*
IL: 5.22 (from records)
Resident Type: 150 PVC
A: 13.50 m2
11
Resident 10
12
A: 13.50 m2
Resident 7
A: 13.50 m2
9
Resident
A: 13.50 m2 SW Field Inlet:IL: 3.564Type: 150 PVC
13 8
14
Visitor
A: 13.50 m2
SW Field Inlet:IL: 2.296Type: 150 PVC
Resident
Sewer MH:
A: 13.50 m2
IL: 4.955
Type: 150 PVC 4
SW Field Inlet:IL: 2.274Type: 150 PVC
Sewer MH:IL: 4.936Type: 225 PVC
SW Field Inlet:IL: 3.470Type: 150 PVC
MH MH
Resident Sewer MH:IL: 4.972Type: 150 PVC
Resident A: 13.50 m2
A: 13.50 m2
5
EMT Z - SP298783
Resident
A: 13.50 m2
SW Field Inlet:IL: 3.365Type: 150 PVC
7 Sewer MH:IL: 2.382Type: 225 PVC
13 SW Field Inlet:IL: 3.355Type: 150 PVC
Resident
Sewer MH:IL: 1.946Type: 225 PVC
A: 13.50 m2
3
12 Visitor
A: 13.50 m2
11 10
Resident
A: 13.50 m2
14 9
8
Resident
15
A: 13.50 m2
Resident
A: 13.50 m2
SW Field Inlet:IL: 6.668Type: 150 PVC
15
Resident
EMT XSP106085
A: 13.50 m2
EMT WSP106085
Resident
Resident
14 13 A: 13.50 m2
A: 13.50 m2
MH
Resident
A: 13.50 m2
Visitor Sewer MH:(Unable to open)
A: 13.50 m2
Resident
A: 13.50 m2 Resident
A: 13.50 m2
10
14 12 11
Resident 9
A: 13.50 m2 Resident
A: 13.50 m2 8
15
Sewer Line: US IL: 10.863Type: 150
RCP
#DrgID #DrgID
#LayID #LayID
B L A C K
SITE PLAN THE AVALON
W O O D
DA1.06
Scale Project No. Date Revision
13/09/2024 A For Devtex Nominees Pty Ltd
1:500, 1:2.61 @ A3 202507
a r c h i t e c t u r e & d e s i g n 73-77 Eumundi Noosa Rd + 2C/2D/2E Starboard Ave, Noosaville QLD 4566
Section 22
APPENDIX B: PRELIMINARY
ENGINEERING DESIGN PLANS
73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-0 17
Section 23
73-77 EUMUNDI-NOOSA ROAD
NOOSAVILLE, QLD 4566
CIVIL ENGINEERING DRAWINGS
for DEVTEX NOMINEES PTY LTD
DRAWING SCHEDULE
DRAWING NO. REVISION DESCRIPTION
24572 - C01 B COVER SHEET, LOCALITY PLAN AND DRAWING SCHEDULE
24572 - C02 B EARTHWORKS LAYOUT PLAN
24572 - C03 B ROADWORKS AND STORMWATER LAYOUT PLAN
24572 - C04 B ROAD LONGITUDINAL SECTIONS AND TYPICAL SECTIONS
LOCATION OF 24572 - C05 B SEWERAGE RETICULATION LAYOUT PLAN
WORKS 24572 - C06 B WATER RETICULATON LAYOUT PLAN
24572 - C07 B REFUSE VEHICLE SWEPT PATH LAYOUT PLAN
24572 - C08 B B99 CAR VEHICLE SWEPT PATH LAYOUT PLAN
LOCALITY PLAN
NOT TO SCALE
COPYRIGHT © Associated Consultants Client Drawn Verified Project Drawing Title Scale Sheet Size
M.K.P. D.R.
This drawing is subject to
copyright in accordance with DEVTEX NOMINEES 73-77 EUMUNDI-NOOSA ROAD COVER SHEET, LOCALITY PLAN AS SHOWN A1
the agreement between TOD Designed Verified
Consulting Pty Ltd (tc) and tc's PTY LTD M.K.P. D.R. NOOSAVILLE, QLD 4566 AND DRAWING SCHEDULE Drawing Number
client. This drawing shall only
be used for this specific project. Approved RPEQ No RP DESCRIPTION LOTS 1, 2 3, 48, 49 AND 50 ON SP298783 24572-C01
This drawing shall not be used Noosa: 07 5449 9600 Sunshine Coast: 07 5329 3190 D. REYNOLDS 9072 LOCAL AUTHORITY NOOSA SHIRE COUNCIL
B 20.09.24 ISSUED FOR APPROVAL MKP MCU APPROVAL HORIZ DATUM MGA DERIVED 0 10 20 30 40 50 60 Sheet Revision
for construction until marked as PO Box 61, Noosaville, QLD 4566 Signed
A 13.09.24 ISSUED FOR APPROVAL MKP ROL APPROVAL VERT DATUM RL.13.595 AHD
'Issued For Construction' in the
revision description. Rev Date Revision Description Drawn
[email protected] www.todconsulting.com
ABN 39 128 805 336 13.09.24 OPW APPROVAL RL DATUM PSM 53205 MEASUREMENT BAR - INCREMENTS IN mm 1 OF 8 B
Section 24
N
LEGEND N
N
N
76.0 NATURAL CONTOUR
N
W
T
W
5
EUMUN
N
76.0 DESIGN CONTOUR SP305303
N
N
PROPERTY BOUNDARY N
EXISTING BITUMEN EDGE 3
W
T
W
N
SP305303 S S S
S
DI-NOO
S
N
S S S
EXISTING KERB N T S S II II II
N II II II
0.2 II II II 4
EXISTING STORMWATER LINES 1.0 II II II 0.8
1.4 II 0.8 SP298783
0.5 II II II1.6 II II
0.2 1.0
NW
N
II II
II
W
KERB AND CHANNEL
10.8
10.8
11.0
9.0
0.8
10.0
S
T
0.8
1.2
0.2
11.0
1.0
1.1
8.0
12.0
A ROA
CONTROL LINE 0.4
E
0.2
S
13.0
S
E
CONCRETE BLOCK RETAINING WALL
FOR CONTINUATION REFER BELOW
II
N
0.8
N E
W
WALL HEIGHT
T
W
D
N
14.0
7.0
EARTHWORKS DEPTHS (0.5m INCREMENTS) T
S
N T
E
II
CUT FILL
E
N
S
REMOVE REDUNDANT N
W
0.5
W
0.2
14.0
EXISTING DRIVEWAY E E
13.8
N E E
S
E
N
N
S
1.2 1
1.1 1.1
W
S
W
11.0
S
II
S
11.0
S
W
N
6.0
S
.2
T N
SW
E
S
SW SW
SW SW
SW
6.0
SW SW II II II
II
II
W
N
W
0.2
S
W
0.4
T
II
S
II II II
II
II
II II
13.0
E
N
SW
SW
II
11.
11.0
W
11.2
11.4
11.6
11.8
12.0
W
12.2
12.4
12.6
12.8
13.0
0
13.2
13.4
13.6
13.8
14.0
14.2
S
7.0
14.4
14.6
II
T
S
II
W
E
N
SW
SW
II
W
W
108
S
1.2 0 9.0
1.1
T
SP106085
II
S
N
SW
SWW
E
.9
Section 25
1.1
II
II
12.0
10.0
8.0
W
11.0
14.
REMOVE REDUNDANT
S
0
II
SW
N
T
SW
EXISTING DRIVEWAY
W
E
II
W
S
15.0
11.0
0.7
W
11
SW
II
N
.0
SW
II
S
T
W
II
T T T
W
S
14.0
13.8
N
SW SW SW
SW
SW
II SW
W
II II SW SW
II
II II II SW SW SW
II
T 13.0
0.9 0.6
II
1.1 1.1
W
T
T
T
T
N
SW
14 6.2
II
.0
II
WN
11.0
REMOVE REDUNDANT
N
11.0
15.0
EXISTING DRIVEWAY
II
N
S
T
SW
II
T
W
N
II
N
W
109
15.0 N
II
SP106085
SW
S
N
N
W
T
II
SW
II
1.1
W
N
6.4
SW
II
N
6.6
S
N
II
SW
W
T
6.8
II
8.0
7.0
N
W
7.2
N
0.2
1.1
0.6
9.0
SW
0.2
II
14.0
1.1 0.4 7.4 II II
SW
1.3 0.4 II II II II II II
7.6
10.
II II II II II II
W
0.5 II II
T
II 1.3 II II II II II II
0
II II
0.2 0.5 II II II
N
W
II II II SW
II II II II SW
II
SW
S
W
T
75
N
SW
RP71151
W
II II
107
S
SP106085
W
N
T
SW
W
W
FOR CONTINUATION REFER ABOVE
SW
5
SP298783
S
STARBOARD AVENUE
E
W
SW
E E E
II
E E E E
E E E
E
S
E
4.0
SW
E
SW
W
E
S S S S S S S
The text continues on section 26.