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Noosa Landfill RRA Flood Assessment
Noosa Landfill RRA Flood
Assessment
Prepared By:
Hydrology and Water
Management Consulting Pty Ltd
Prepared for:
Noosa Council
Reference: J00352R1V2
Date: 6/04/2022
Hydrology and Water Management Consulting Pty Ltd
PO Box 120 Coolum Beach Qld 4573
Mob 0405 194 639
Email [email protected]
Web www.hydrologyandwater.com.au
ABN 25 153 466 981 ACN 153 466 981
J00352R1V2 i
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Page 2
Noosa Landfill RRA Flood Assessment
Disclaimer
This report has been prepared on behalf of and for the exclusive use of Noosa Council (the client). It is subject to the
provisions of the agreement between Hydrology and Water Management Consulting Pty Ltd (HWMC) and the client.
HWMC accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any
third party. This report should not be used for purposes other than those for which it has been prepared.
Copyright
The information and concepts contained in this document are the property of Hydrology and Water Management
Consulting Pty Ltd (HWMC). Use or copying of this document in whole or in part without the written permission of HWMC
constitutes an infringement of copyright.
Document Details
Item No. Data
Report Title Noosa Landfill RRA Flood Assessment
Prepared For Noosa Council
Date 6/04/2022
Document Ref J00352R1V2
Report Status Final
Prepared By:
Name Rob Stewart
Qualifications BE (Civil)
Certification By:
Name Rob Stewart
RPEQ No 13272
Signature
J00352R1V2 ii
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Noosa Landfill RRA Flood Assessment
TABLE OF CONTENTS
1 INTRODUCTION ............................................................................................................................................... 1
2 AVAILABLE DATA ............................................................................................................................................. 2
3 BASE CASE MODELLING ................................................................................................................................... 3
3.1 HYDRAULIC MODEL SOFTWARE ............................................................................................................................. 3
3.2 TOPOGRAPHY ..................................................................................................................................................... 3
3.3 STRUCTURES ...................................................................................................................................................... 4
3.4 HYDRAULIC ROUGHNESS....................................................................................................................................... 5
3.5 DESIGN RAINFALL ................................................................................................................................................ 6
4 VALIDATION .................................................................................................................................................... 7
5 PROPOSED CASE MODELLING .......................................................................................................................... 8
6 RESULTS ......................................................................................................................................................... 10
7 ADVICE RELATING TO FUTURE PLANNING AND DESIGN ................................................................................. 12
8 CONCLUSIONS ............................................................................................................................................... 13
9 QUALIFICATIONS & LIMITATIONS .................................................................................................................. 14
10 REFERENCES .................................................................................................................................................. 15
List of Appendices
Appendix A Rational Method and Design Rainfall
Appendix B Base Case Flood Mapping
Appendix C Proposed Case Flood Mapping
Appendix D Peak Flood Level Impact Mapping
J00352R1V2 iii
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Noosa Landfill RRA Flood Assessment Abbreviations 1D One-Dimensional 2D Two-Dimensional AEP Annual Exceedance Probability ARI Average Recurrence Interval AHD Australian Height Datum ARR Australian Rainfall and Runoff BoM Bureau of Meteorology DEM Digital Elevation Model DFE Design Flood Event DTMR Department of Transport and Main Roads (Queensland) EY Exceedances Per Year FHO Flood Hazard Overlay FMS Flood Management Strategy GIS Geographic Information Systems HWMC Hydrology and Water Management Consulting Pty Ltd EA Engineers Australia FI Fraction Impervious IFD Intensity Frequency Duration (rainfall intensity data) MRM Modified Rational Method RCP Reinforced Concrete Pipe RCBC Reinforced Concrete Box Culvert RFFE Regional Flood Frequency Estimation RRA Resource Recovery Area TIN Triangular Irregular Network TMR Department of Transport and Main Roads (QLD Gov) QUDM Queensland Urban Drainage Manual J00352R1V2 iv
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Noosa Landfill RRA Flood Assessment
1 INTRODUCTION
Hydrology and Water Management Consulting Pty Ltd (HWMC) has been commissioned by Noosa
Council to carryout flood modelling to assess the potential impact of proposed filling associated
with the expansion of the Resource Recovery Area (RRA) at the Noosaville Landfill Site.
The purpose of this assessment is to:
1. Determine design flood levels that can be used to define minimum floor levels on the site.
2. Determine whether the proposed fill is expected to cause any adverse flood impacts.
The landfill site is located at 561 Eumundi Noosa Rd, Doonan. The location of the proposed filling
area is shown on Image 1-1
Image 1-1 Proposed Fill Location
J00352R1V2 1
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Noosa Landfill RRA Flood Assessment
2 AVAILABLE DATA
The following information has been supplied to HWMC for use in this project.
Table 2-1 Information Used for this Investigation
Item
Information Source
No.
1 Aerial imagery and LiDAR of the Landfill Site captured in 2020 by Drone IQ.
2 Preliminary Stormwater Catchments Plans by Topo (Feb 2021),
3 Aerial LiDAR Survey captured in 2015.
4 Design Rainfall Information from the Bureau of Meteorology (BoM).
J00352R1V2 2
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Noosa Landfill RRA Flood Assessment 3 BASE CASE MODELLING Base case flood modelling has been undertaken with the site in its existing condition. 3.1 Hydraulic Model Software Hydraulic modelling has been carried out using TUFLOW HPC software developed by BMT WBM in Brisbane. TUFLOW HPC is a 1D / 2D finite volume numerical model that is used to simulate hydrodynamic flow in rivers, floodplains and urban catchments. It is widely used in Australia and overseas. TUFLOW HPC version 2020-10-AA_64_iSP has been used for this investigation. 3.2 Topography Model topography is defined using a 2D fixed grid with a 3m cell size. TUFLOW’s Sub Grid Sampling with a 1m grid size has also been applied to enable the 3m cells to better reflect ground levels. Model topography levels are based on Noosa Council’s 2015 Aerial LiDAR Survey (ALS) external to the site. The landfill site is represented using 2020 LiDAR collected by a drone. Where necessary local adjustments have been made to ensure key features such as road embankments are correctly represented in the model. Model ground levels in the vicinity of the site are shown on Image 3-2. J00352R1V2 3
Page 8
Noosa Landfill RRA Flood Assessment Image 3-1 Base Case Model Ground Levels in Vicinity of the Site 3.3 Structures Hydraulic structures have been incorporated into the model based on field inspections and on council GIS data. There are no pipes or culverts that have a significant impact on flooding characteristics at the proposed RRA expansion area and therefore survey of hydraulic structures has not been carried out. Pipes and culverts have been modelled as 1D network elements with zero blockage. Hydraulic structure locations are shown on Image 3-2. J00352R1V2 4
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Noosa Landfill RRA Flood Assessment
Image 3-2 Hydraulic Structure Locations
3.4 Hydraulic Roughness
Manning’s ‘n’ hydraulic roughness values applied to the TUFLOW modelling are shown on Table
3-1.
Table 3-1 Manning’s ‘n’ Values
Landuse / Surface Type Manning’s ‘n’
Cleared Open Space / Site 0.04
Light Vegetation / Rural Residential 0.06
Roads 0.02
Bushland 0.10
Waterbodies 0.03
Culverts 0.013
J00352R1V2 5
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Noosa Landfill RRA Flood Assessment
3.5 Design Rainfall
Design rainfall has been applied to the model using direct rainfall on grid. ARR2019 ensemble
temporal patterns have been applied to the model for a range of duration events and then peak
flood characteristics have been selected at each cell based on the critical duration and the
associated median ensemble pattern. This process is undertaken using TUFLOW result
processing tools and is undertaken for each individual cell in the model. This methodology is in
accordance with the latest ARR2019 guidelines.
Modelling has been undertaken for events with durations of 30, 60, 120 and 180 minutes.
Modelling has been carried out for the following design event probabilities for the base case and
proposed case modelling:
• 50% AEP (Q2)
• 10% AEP (Q10)
• 1% AEP Current Climate (Q100)
• 1% AEP Year 2100 Climate
The following ‘rare’ events have also been simulated for the proposed case:
• 0.5% AEP (Q200)
• 0.2% AEP (Q500)
• 0.1% AEP (Q1000)
The latest available design rainfall intensity data has been taken from the Bureau of Meteorology
(BoM) IFD website.
J00352R1V2 6
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Noosa Landfill RRA Flood Assessment
4 VALIDATION
Validation of peak flows at the proposed RRA fill site has been carried out against a Rational
Method peak flow calculation. Details of the Rational Method calculation are provided in Appendix
A. The peak flow comparison shown below demonstrates a good level of agreement between the
TUFLOW results and the Rational Method.
Table 4-1 Peak Flow Validation at Northern Boundary of the Landfill Site
Rational Method Peak Flow (1% AEP) 12.8 m3/s
TUFLOW Peak Flow (1% AEP)
(Critical Duration of 30 minutes) 14.0 m3/s
Difference + 9.4%
J00352R1V2 7
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Noosa Landfill RRA Flood Assessment 5 PROPOSED CASE MODELLING The proposed RRA fill pad has been incorporated into the model using TUFLOW z-point modifiers. The site fill area has been raised to above the DFE flood level and graded to fall northwards. Details of the proposed case model topography are shown on image 5-1. Image 5-1 Proposed Case Model Topography The proposed case ground level assumptions modelled are appropriate for an initial constraints assessment but will need to be refined as part of future detail design. Finished floor levels of any buildings constructed on the fill pad will need to achieve the minimum levels shown on Image 5-2. This will ensure finished floor levels are a minimum of 300mm above the DFE peak flood levels. J00352R1V2 8
Page 13
Noosa Landfill RRA Flood Assessment Image 5-2 Minimum floor heights (300mm freeboard above 1% AEP Year 2100 Flood) J00352R1V2 9
Page 14
Noosa Landfill RRA Flood Assessment 6 RESULTS Base Case and Proposed Case peak flood depth maps are provided in Appendix B and C respectively. Modelling predicts that the area of proposed filling is subject to peak depths of up to approximately 700mm in the base case modelling of the DFE event. Peak DFE flood levels are predicted to increase by up to approximately 600mm around the fill pad in the proposed case. Peak flood level impact mapping is provided in Appendix D. For ease of reference an extract of the DFE peak flood level impact map is provided on Image 6-1. The impact mapping shows that the proposed fill pad is predicted to cause a re-distribution of floodwaters across the northern site boundary. There are increased flood levels on the western side of the floodplain and reduced levels on the eastern side downstream of the fill pad. These impacts occur in bushland areas only so are likely to be of no consequence. If necessary, it would be possible to significantly mitigate this effect by including a flow spreading channel along the norther edge of the fill. The predicted flood level increases do not affect any infrastructure on the site or the surrounding area. Proposed case peak flood levels in the drains surrounding the RRA fill pad are shown on Image 6- 2. Proposed case peak flood velocities in the area are less than approximately 1.2m/s. Image 6-1 Extract of the 1% AEP Year 2100 Peak Flood Level Impact Map (DFE) J00352R1V2 10
Page 15
Noosa Landfill RRA Flood Assessment Image 6-2 Design Flood Levels Adjacent to RRA Fill Pad J00352R1V2 11
Page 16
Noosa Landfill RRA Flood Assessment 7 ADVICE RELATING TO FUTURE PLANNING AND DESIGN This assessment has considered a preliminary design of the RRA fill pad. As further design and planning of this facility proceeds it is likely that the RRA filling will be revised. It is recommended that HWMC be consulted through this process to ensure that the positive outcomes for this assessment are maintained. The fill pad modelled for this assessment excludes filling over the existing bioretention system northeast of the RRA. HWMC foresee no issue with this bioretention system being removed to make way for the RRA provided that the site’s water quality obligations are met and site runoff to this location is appropriately managed. The fill pad modelled for the current assessment directs local RRA runoff northwards. This was done to provide a level of conservatism to the results by not having RRA runoff be subject to storage attenuation associated with the existing sediment pond south of the RRA. HWMC foresee no issue with directing RRA runoff to the existing sediment pond to the south however this is likely to alter internal site flood levels and therefore analysis should be undertaken to ensure facilities maintain appropriate levels of flood immunity. J00352R1V2 12
Page 17
Noosa Landfill RRA Flood Assessment 8 CONCLUSIONS Hydrology and Water Management Consulting Pty Ltd has completed this flood assessment to inform preliminary planning and design of a proposed Resource Recovery Area (RRA) at the Noosaville Landfill Site. This work has been completed for Noosa Council. Detailed flood models have been established and validated. These have been used to create flood maps for the existing and proposed cases. The impact on peak design flood levels likely to be caused by the RRA filling has been described. There is a re-distribution of floodwaters in the floodplain downstream of the filling however there are no adverse impacts that are likely to affect any infrastructure on the site or surrounding area. Results of this assessment should be used to guide planning and design of the project. Flood modelling will need to be updated as part of future design to ensure positive flood outcomes are achieved. J00352R1V2 13
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Noosa Landfill RRA Flood Assessment 9 QUALIFICATIONS & LIMITATIONS In preparing this report, HWMC has relied upon and assumed accurate data provided by Noosa Council. Unless otherwise stated in this report, HWMC has not attempted to verify the accuracy or completeness of any such information. The accuracy of this report is reliant upon the accuracy of this information. The results presented in this report are based on modelling of theoretical design flood events. It is not possible to investigate all possible combinations of real-world storm conditions and it is important to note that actual flood characteristics and associated impacts may differ from those presented in this report. The level of detailed provided in this investigation is appropriate for supporting the current planning and preliminary design phase of this development. Additional analysis will be required as the project progresses to more detailed planning and design phases. This report should be read in full and no excerpts are to be taken as representative of the findings. No responsibility is accepted by HWMC for use of any part of this report in any other context. Study results should not be used for purposes other than those for which they were prepared. J00352R1V2 14
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Noosa Landfill RRA Flood Assessment
10 REFERENCES
1. BMT WBM, 2018, “TUFLOW User Manual”
2. Ball J, Babister M, Nathan R, Weeks W, Weinmann E, Retallick M, Testoni I, (Editors),
Commonwealth of Australia, 2016, “Australian Rainfall and Runoff: A Guide to Flood
Estimation”
3. Institute of Public Works Engineering Australasia, Queensland Government, 2016,
“Queensland Urban Drainage Manual, 4th Edition” (QUDM)
4. Michael Boyd et al, 2012, “WBNM User Guide”
5. Michael Boyd et al, 2007, “Details of the Theory Used in WBNM”
J00352R1V2 15
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APPENDIX A Rational Method and Design Rainfall
Page 21
RATIONAL METHOD SUMMARY & RAINFALL DATA Project: Location: Design Rainfall Depths (mm) J00352_Noosa_Landfill_RRA_Flood_Assessment Northern Site Outlet Duration 63.2% 50% 20% 10% 5% 2% 1% Duration (minutes) AEP AEP AEP AEP AEP AEP AEP 1 min 1 2.85 3.22 4.36 5.11 5.82 6.73 7.40 2 min 2 4.82 5.48 7.56 8.99 10.40 12.30 13.80 3 min 3 6.81 7.73 10.60 12.60 14.50 17.10 19.10 4min 4 8.64 9.80 13.40 15.80 18.20 21.30 23.60 5 min 5 10.30 11.70 15.90 18.70 21.40 24.90 27.60 10 min 10 16.90 19.10 25.70 30.00 34.10 39.20 43.00 15 min 15 21.50 24.20 32.60 38.10 43.20 49.60 54.40 20 min 20 25.00 28.20 38.00 44.40 50.40 58.10 63.70 25 min 9) 27.80 31.50 42.50 49.70 56.50 65.30 71.70 30 min 30 30.20 34.20 46.30 54.20 61.80 71.60 78.90 45 min 45 35.90 40.60 55.50 65.30 74.90 87.40 96.90 1 hour 60 40.20 45.60 62.70 74.20 85.40 100.00 112.00 1.5 hour 90 46.80 53.40 74.20 88.40 103.00 121.00 136.00 2 hour 120 52.10 59.60 83.60 100.00 117.00 139.00 156.00 3 hour 180 60.60 69.70 99.00 119.00 140.00 168.00 190.00 4.5 hour 270 70.80 81.90 118.00 143.00 168.00 203.00 230.00 6 hour 360 79.30 92.10 133.00 163.00 192.00 232.00 264.00 9 hour 540 93.20 109.00 159.00 195.00 231.00 281.00 320.00 12 hour 720 105.00 122.00 180.00 222.00 264.00 321.00 367.00 18 hour 1080 122.00 144.00 213.00 264.00 315.00 386.00 | 442.00 24 hour 1440 136.00 160.00 239.00 296.00 356.00 | 437.00 503.00 30 hour 1800 148.00 173.00 260.00 323.00 389.00 | 480.00 553.00 36 hour 2160 157.00 184.00 277.00 345.00 | 416.00 516.00 597.00 48 hour 2880 172.00 202.00 304.00 380.00 | 460.00 574.00 667.00 72 hour 4320 192.00 225.00 340.00 | 427.00 520.00 654.00 766.00 96 hour 5760 206.00 241.00 363.00 | 458.00 559.00 706.00 829.00 120 hour 7200 216.00 253.00 381.00 | 479.00 586.00 741.00 871.00 144 hour 8640 225.00 262.00 394.00 | 496.00 606.00 765.00 898.00 168 hour 10080 232.00 271.00 | 406.00 509.00 621.00 781.00 914.00 Catchment Data Details: Northern Site Outlet Variable Value Units Area: 37.00 ha C10 0.70 fraction Rational Method Summary Time of Concentration (tc) 34.0 _ Minutes (or 0.57 hours) 63.2% 50% 20% 10% 5% 2% 1% Variable AEP AEP AEP AEP AEP AEP AEP Freq Factor 0.80 0.85 0.95 1.00 1.05 1.15 1.20 Intensity (mm/hr) 56.22 63.63 86.41 101.31 115.73 134.37 148.35 Discharge (m3/s) 3.24 3.89 5.91 7.29 8.75 11.13 12.82
Page 22
APPENDIX B Base Case Flood Mapping
Page 23
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Base Case
(TUFLOW Case B01a)
1% AEP Event
Future Climate at Year 2100
Client: Noosa Council
Plan Ref: J00352_B01a_d_1pcAEP_CC
Page 24
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Base Case
(TUFLOW Case B01a)
1% AEP Event
Client: Noosa Council
Plan Ref: J00352_B01a_d_1pcAEP
Page 25
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Base Case
(TUFLOW Case B01a)
10% AEP Event
Client: Noosa Council
Plan Ref: J00352_B01a_d_10pcAEP
Page 26
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Base Case
(TUFLOW Case B01a)
50% AEP Event
Client: Noosa Council
Plan Ref: J00352_B01a_d_50pcAEP
Page 27
APPENDIX C Proposed Case Flood Mapping
Page 28
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Proposed Case
(TUFLOW Case P01a)
1% AEP Event
Future Climate at Year 2100
Client: Noosa Council
Plan Ref: J00352_P01a_d_1pcAEP_CC
Page 29
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Proposed Case
(TUFLOW Case P01a)
1% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_d_1pcAEP
Page 30
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Proposed Case
(TUFLOW Case P01a)
10% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_d_10pcAEP
Page 31
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Depth (m)
<= 0.2
0.2 - 0.5
0.5 - 0.75
0.75 - 1
1 - 1.25
1.25 - 1.5
1.5 - 1.75
1.75 - 2
>2
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Depth
Proposed Case
(TUFLOW Case P01a)
50% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_d_50pcAEP
Page 32
APPENDIX D Peak Flood Level Impact Mapping
Page 33
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Impact (mm)
Less than 200
-100 to -200
-50 to -100
-20 to -50
-10 to -20
10 to -10
10 to 20
20 to 50
50 to 100
100 to 200
Greater than 200
Was Wet - Now Dry
Was Dry - Now Wet
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Level Impacts
Proposed Case Vs Base Case
(TUFLOW Case P01a - B01a)
1% AEP Event
Future Climate at Year 2100
Client: Noosa Council
Plan Ref: J00352_P01a_Diff_h_vs_B01a_1pcAEP_CC
Page 34
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Impact (mm)
Less than 200
-100 to -200
-50 to -100
-20 to -50
-10 to -20
10 to -10
10 to 20
20 to 50
50 to 100
100 to 200
Greater than 200
Was Wet - Now Dry
Was Dry - Now Wet
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Level Impacts
Proposed Case Vs Base Case
(TUFLOW Case P01a - B01a)
1% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_Diff_h_vs_B01a_1pcAEP
Page 35
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Impact (mm)
Less than 200
-100 to -200
-50 to -100
-20 to -50
-10 to -20
10 to -10
10 to 20
20 to 50
50 to 100
100 to 200
Greater than 200
Was Wet - Now Dry
Was Dry - Now Wet
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Level Impacts
Proposed Case Vs Base Case
(TUFLOW Case P01a - B01a)
10% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_Diff_h_vs_B01a_10pcAEP
Page 36
LEGEND
DCDB
1m Contour (2015 LiDAR)
Model Extent
Downstream Boundary
Proposed Case Topo Modifier
Culvert (1d_nwk)
Impact (mm)
Less than 200
-100 to -200
-50 to -100
-20 to -50
-10 to -20
10 to -10
10 to 20
20 to 50
50 to 100
100 to 200
Greater than 200
Was Wet - Now Dry
Was Dry - Now Wet
Flood mapping only shown where depths are
greater than 50mm
© Hydrology and Water Management Consulting Pty Ltd (HWMC) 2021.
HWMC endeavours to ensure that the information contained in this
figure is correct at the time of publication. Furthermore, HWMC makes
no representations, warranties or guarantees about its accuracy,
reliability, completeness or suitability for any particular purpose.
HWMC Ref: J00352_Noosa_Landfill_RRA_Flood_Assessment
Noosa Landfill RRA Flood Assessment
Peak Flood Level Impacts
Proposed Case Vs Base Case
(TUFLOW Case P01a - B01a)
50% AEP Event
Client: Noosa Council
Plan Ref: J00352_P01a_Diff_h_vs_B01a_50pcAEP