West Mackay Drainage Study

Mackay Regional Council 11-Sep-2019 Doc No. M031-19

Volume 1 Report

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

West Mackay Drainage Study Volume 1 Report

Client: Mackay Regional Council

ABN: 56 240 712 069

Prepared by

AECOM Australia Pty Ltd Level 1, 162 Victoria Street, PO Box 11176, Mackay QLD 4740, Australia T +61 7 4965 9800 F +61 7 4957 6097 www.aecom.com ABN 20 093 846 925

11-Sep-2019

Job No.: 60589930

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Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

Quality Information

Document West Mackay Drainage Study

Ref 60589930

Date 11-Sep-2019

Prepared by Matthew Buckley

Reviewed by Sally Williams

Submitted by Trevor Corney

Revision History

Authorised Rev Revision Date Details Name/Position Signature

Sally Williams A 11-Sep-2019 Final Associate Director (RPEQ – 19353)

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

Table of Contents Executive Summary i 1.0 Introduction 1 1.1 Project Background 1 1.2 Study Objectives 1 1.3 Methodology 2 1.4 Notes on Flood Frequency 2 1.5 Limitations and Exclusions 3 1.5.1 Interpretation of Results 4 1.6 Report Structure 4 2.0 Study Area and Key Characteristics 5 2.1 Study Area 5 2.2 Catchment Characteristics 7 2.3 Climate Characteristics 7 2.3.1 Rainfall Regime 7 3.0 Available Data 9 3.1 General 9 3.2 Previous Reports 9 3.2.1 West Mackay Drainage Study (Ullman & Norman Pty Ltd, 2003) 9 3.3 Rainfall Data 9 3.4 Tidal Data 10 3.5 Topographical Data 10 3.5.1 Aerial Photography 10 3.6 Event Recorded Data 10 3.6.1 2008 Flood Levels 10 3.7 Existing Stormwater Drainage Infrastructure 10 3.7.1 Pipe and Pit Network Details 10 3.7.2 Culverts 11 3.8 Proposed Stormwater Drainage Infrastructure 11 3.9 GIS Data 11 4.0 Hydrologic Assessment 11 4.1 Overview 11 4.2 Adopted Methodology 11 4.2.1 Design Rainfall Intensity-Frequency Duration (IFD) Data 12 4.2.2 Temporal Patterns 12 4.2.3 Areal Reduction Factors 12 4.2.4 Probable Maximum Precipitation Event 12 4.3 Hydrologic Model Validation 13 5.0 Hydraulic Model Development 14 5.1 Overview 14 5.2 Adopted Methodology 14 5.2.1 Modelling Cross Drainage Structures 16 5.2.2 2D Modelling Roughness 16 5.3 Critical Duration Assessment 16 5.4 Calibration and Validation 20 5.4.1 Comparison of Results to 2008 Flood Levels 20 6.0 Basecase Hydraulic Modelling 23 6.1 Overview 23 6.2 Basecase Peak Flood Depths, Extents and Velocities 23 6.2.1 Basecase Peak Water Surface Elevation 26 6.2.2 Basecase Peak Discharges 27 6.2.3 Basecase Underground Network Capacity 28 6.2.4 Basecase Property Impacts 28 6.2.5 Hospital Stormwater Drainage Infrastructure 29 6.3 Sensitivity Analysis 32 6.3.1 Hydraulic Roughness 32 6.3.2 Continuing Losses 32

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

7.0 Effects of Climate Change 33 7.1 General 33 7.2 Adopted Approach 34 7.3 Hydraulic Model Results 34 7.4 Planning Scheme Flood Mapping 34 8.0 Structural Mitigation Options 35 8.1 Overview 35 8.2 Design Peak Flood Depths, Extents and Discharges 38 8.2.1 Mitigated Case Peak Water Surface Elevations 38 8.2.2 Mitigated Peak Discharges 39 8.3 Difference in Peak Water Surface Elevation 40 8.4 Mitigated Property Impacts 42 8.4.1 Mitigated Case Underground Network Capacity 43 9.0 Tangible Flood Damages Assessment 46 9.1 Objectives 46 9.2 Estimating Flood Damages 46 9.3 General Methodology 47 9.3.1 Council 2018 Stage-Damage Curves 47 9.3.2 Alternative Approaches 48 9.3.3 Actual and Potential Damages 49 9.4 Building Digitisation and Classification 49 9.4.1 Building Footprint Digitisation 49 9.4.2 Classification 49 9.5 Terrestrial LiDAR Data 50 9.5.1 Ground Levels 51 9.6 Consumer Price Index Adjustment 51 9.7 Damage Categories 53 9.8 Classifications and Damage Curves 53 9.8.1 Residential 53 9.8.2 Commercial 53 9.9 Infrastructure Damages 53 9.10 Average Annual Damages (AAD) 54 10.0 Flood Damages Assessment Results 54 10.1 Present Case – Flood Damages Estimate 55 10.2 Mitigation Case - Flood Damages Estimate 56 10.3 Comparison 57 10.4 Mitigation Case - Other Improvements 59 11.0 Indicative Mitigation Infrastructure Costs 59 11.1 Structural Mitigation Costs 59 12.0 Cost Benefit of Stormwater Mitigation 59 13.0 Conclusion and Recommendations 60 13.1 Key Findings 60 14.0 References 61 Appendix A Hydraulic Model Development A Model Setup Parameters A-1 One Dimensional Model Development A-1 Model Topography A-1 Hydraulic Roughness and Losses A-1 Initial Conditions A-3 Appendix B Damage Categories and Curves B-6 Residential Property Sub-Categories B-1 Commercial Categories B-1 Building Footprint Size B-3 Fully Detached Residential Damages B-3 Indirect Fully Detached Residential Damages B-6 Multi-Unit Residential Damages B-6

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

Indirect Multi-Unit Residential Damages B-8 Commercial Damages B-8 Indirect Commercial Damages B-10 Appendix C Property Impacts Assessment C Property Floor Levels and Classification C-1

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

List of Tables Table 1 Flood Frequency Classification 2 Table 2 BOM 2016 IFD Design Rainfall Depth (mm) 10 Table 3 Intensity Frequency Duration (IFD) Data for West Mackay (BOM, 2016) 12 Table 4 Adopted PMP Parameters 13 Table 5 TUFLOW model Parameters 14 Table 6 Summary of Baseline Peak Water Surface Elevations and Critical Duration 20 Table 7 Summary of Baseline Peak Water Surface Elevations 26 Table 8 Peak Discharges at Select Locations for Basecase Design Events 27 Table 9 Modelling Scenario – Basecase 1d Network Capacity 28 Table 10 Modelling Scenario – Basecase Building Inundation Numbers in Study Area 1 28 Table 11 Projected Sea Level Rise (SPP 3/11, 2012) 33 Table 12 Summary of Mitigated Case Peak Water Surface Elevations 38 Table 13 Peak Discharges at Select Locations for Mitigated Design Events 39 Table 14 Summary of Difference in Peak Water Surface Elevations (Base Case – Mitigated Case) 40 Table 15 Basecase Property Impacts 42 Table 16 Mitigated Case Property Impacts 42 Table 17 Difference in Property Impacts 42 Table 18 Modelling Scenario – Mitigated Case 1d Network Capacity 43 Table 19 Example Flood Damages Terrestrial LiDAR Attribute Table 51 Table 20 Council Stage-Damage Curves CPI Adjustment Summary (Mar 2019 $) 52 Table 21 Historical Stage-Damage Curves CPI Adjustment Summary (March 2019 $) 52 Table 22 Comparative Tangible Flood Damages Assessment Results - Present Case (, 000’s March 2018 $) 55 Table 23 Comparative Tangible Flood Damages Assessment Results - Mitigated Case (, 000’s March 2018 $) 56 Table 24 Comparative Tangible Flood Damage Assessment Results – Change in Flood Damages (%) (Basecase vs Mitigated Case) 57 Table 25 Indicative Structural Mitigation Construction Costs 59 Table 26 Adopted Roughness Values A-2 Table 27 Adopted Initial and Continuing Loss Values A-2 Table 28 Differences in Water Level at Selected Locations for 1% AEP Storm Events for 1987 pattern A-4 Table 29 Differences in Water Level at Selected Locations for 1% AEP Storm Events for 2016 patterns A-4 Table 30 Assignment of Commercial Damage Class Curves Based on Council Land Use Dataset B-2 Table 31 Property Floor Levels and Classifications C-1

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

List of Figures Figure 1 Study Methodology 2 Figure 2 Catchment Characteristics and Topography – Study Area 1 5 Figure 3 Catchment Characteristics and Topography – West Mackay 6 Figure 4 Mackay Aero Meteorological Office Rainfall Statistics (BoM, 2019) 8 Figure 5 Model Setup and 1D Network Map 15 Figure 6 Hydraulic Roughness Delineation 17 Figure 7 Baseline Critical Duration Map 1987 Temporal Patterns 18 Figure 8 Baseline Critical Duration Map 2016 Temporal Patterns 19 Figure 9 Locations of 2008 Observed Flood Heights 22 Figure 10 Model Key Points of Interest – Lines 24 Figure 11 Model Key Points of Interest – Points 25 Figure 12 Crowley Drive – Lack of Pit and Pipe data within Hospital Precinct (1% AEP shown). 29 Figure 13 Basecase 1D Pipe Network Capacity 30 Figure 14 Base Case Building Inundation Location Summary 31 Figure 15 Overview of Structural Mitigation Options 36 Figure 16 Overview of Structural Mitigation Options on Douglas, Donaldson, Chataway and Mackenzie Streets 37 Figure 17 Mitigation Case – Building Inundation Locations 44 Figure 18 1D Network Capacity 45 Figure 19 Breakdown of Flood Damage Categories (DNRM, 2002) 46 Figure 20 Visualisation of the Terrestrial LiDAR Database 50 Figure 21 Total Damages and Impacted Properties Plot (1EY to 1% AEP) 58 Figure 22 Total Damages and Impacted Properties Plot (1% AEP to PMF) 58 Figure 23 Locations of Points Comparing Depths for Critical Storms A-5 Figure 24 ANUFLOOD Commercial Damage Value Classes (DNRM, 2002) B-2 Figure 25 Fully Detached Residential Building Classification Flowchart B-4 Figure 26 Combined Stage-Damage Curves: FDSS-SOG B-4 Figure 27 Combined Stage-Damage Curves: FDSS-Stumps B-5 Figure 28 Combined Stage-Damage Curves: FDDS B-5 Figure 29 Combined Stage-Damage Curves: FDHS B-6 Figure 30 Multi-Unit Residential Building Classification Flowchart B-7 Figure 31 Combined Stage-Damage Curves: MUSS B-7 Figure 32 Combined Stage-Damage Curves: MUDS B-8 Figure 33 Commercial Building Classification Flowchart B-9 Figure 34 Total Stage-Damage Curve: Small Commercial B-9 Figure 35 Total Stage-Damage Curve: Medium Commercial B-10 Figure 36 Total Stage-Damage Curve: Large Commercial B-10

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report i

Executive Summary AECOM Australia Pty Ltd (AECOM) has undertaken hydrologic and hydraulic analysis of the West Mackay area on behalf of the Mackay Regional Council (MRC). The primary objectives of the West Mackay Drainage Study are to develop a ‘best practice’ hydraulic model capable of adequately simulating the existing storm water drainage and watercourse flood characteristics, assessing the existing flood risk, and developing flood mitigation recommendations in consultation with MRC. Another key outcome for the study is to complete a flood damages assessment for the base and mitigated flood conditions to assist in determining the potential economic benefits of the proposed flood mitigation options to the West Mackay area during flood events. MRC’s main focus for this flood study was the residential area between the Mackay Base Hospital to Holland Street and encompassing Mogford Street and Barton Street to the south-east. This area has been designated Study Area 1 and is a subset of the overall study area. Structural mitigation options were focused on the installation of a proposed design for a more extensive pit and pipe network within Study Area 1 of the West Mackay region. This storm water drainage network included Holland, Mackenzie, Douglas, Donaldson, Chataway and Barton and Mogford streets. Total indicative costs for building this new drainage are $6,500,000 (excl. GST); Commercial and residential flood damages assessment was undertaken for a range of design flood events using the Council 2018 stage-damage curves. The mitigated case saw a reduction in residential and commercial properties flooding and reduction in both external and internal damages. A reduction of 80% in Average Annual Damages is experienced, of the 80% reduction in AAD, over 60% reduction is experienced in the less frequent, higher order events (≥5% AEP). Improvement in average annual damages costs are vital in determining whether mitigation options will be further investigated; other improvements are difficult to determine a specific dollar value. These improvements include reduction in road closures during flood events and clean-up costs due to flooding in public areas (such as parks) and increased positive public perception due to flood improvement works.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 1

1.0 Introduction West Mackay is located approximately 3 km south west of Mackay CBD on the southern bank of the Pioneer River and on the northern bank of the Lagoons watercourse. The area consists of a rectangular grid of urban streets constructed in the “old style”, with road crowns that are elevated above the footpath.

1.1 Project Background The streets of West Mackay have limited pit and pipe underground infrastructure and this arrangement exhibits excess kerb and channel flows which traverse eastwards overland to the next street. There are several areas of West Mackay where ponding occurs frequently due to low-order rain events. This flooding is a consequence of the flat terrain, a lack of pit and pipe infrastructure and a lack of defined overland flow paths. To potentially reduce future flood risk, MRC is seeking to understand flood behaviour occurring in West Mackay. Of particular interest is the residential area adjacent to the Mackay Base Hospital in the vicinity of Holland St as well as parts of Mogford Street and Barton Street to the south east. Mitigation works to reduce flooding within this area have been proposed for assessment. A flood damage analysis and cost benefit analysis have been used to compare potential mitigation options for the area. The existing underground stormwater infrastructure at West Mackay generally discharges to overland watercourses as follows: • East across Nebo Road from Brooks Street eastwards to Smith Street; • North along Holland Street to discharge adjacent to the Mackay Cemetery; • South along Holland Street to discharge into the Lagoons; • East along Gillian Street and Sneyd Street then across Shakespeare Street; • Jackson Street discharging to the Lagoons; • Mackenzie Street discharging to the Lagoons. The discharge points from Jackson Street and Mackenzie Street are recent additions to the stormwater network that have not been included in previous flood studies of West Mackay.

1.2 Study Objectives The objectives of the West Mackay Drainage Study are to: • Update the existing combined Shellgrit Creek and CBD TUFLOW model in the West Mackay area to reflect current conditions and the in-ground pit and pipe network; • Compare the temporal pattern changes between AR&R 1987 and the ensemble approach incorporated by AR&R 2016 has on water depths for the 1% AEP Rainfall events; • Assess the flood mitigation potential of a stormwater drainage network for West Mackay Study Area 1; • Prepare a preliminary evaluation of the cost / benefit of proposed mitigation options including tangible cost damage assessments of existing and mitigated options; • Determine the current level of service (flood immunity) of existing stormwater trunk infrastructure in the study area; • Provide MRC with data to inform floodplain management and planning.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 2

1.3 Methodology In this study the performance of the existing stormwater infrastructure is first assessed, followed by the development and analysis of potential flood mitigation options which cater for existing and future development conditions. The study methodology is summarised in Figure 1.

Figure 1 Study Methodology

1.4 Notes on Flood Frequency The frequency of flood events is generally referred to in terms of their Annual Exceedance Probability (AEP) or Average Recurrence Interval (ARI). For example, for a flood magnitude with a 5% AEP, there is a 5% probability that there will be a flood of equal or greater magnitude each year. As another example, for a flood having a 5 year ARI, there will be floods of equal or greater magnitude of once in 5 years on average. The correspondence between the two systems is shown in Table 1. Table 1 Flood Frequency Classification Annual Exceedance Average Recurrence Probability (AEP) % Interval (ARI) Years 1EY 1 39 2 18 5 10 10 5 20 2 50 1 100 0.5 200 0.2 500 In this report, the AEP terminology has been adopted to describe the frequency of flooding.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 3

1.5 Limitations and Exclusions The following limitations and exclusions apply to the West Mackay Drainage Study: • Design flood events have been assessed for a single critical duration, based on an analysis of multiple durations for the 1%, 0.5% and 0.2% Annual Exceedance Probability (AEP) event. Critical duration was assessed based on the storm duration which had the greatest impact on the study area; • Aerial survey data (in the form of LiDAR) was used to develop the topography for the hydraulic model (described in Section 3.5). • Where information gaps existed in the MRC underground drainage network, assumptions were made to fill these gaps using desktop assessment methods (described in Section 3.7). • Australian Rainfall and Runoff (AR&R) 2016 ensemble temporal patterns are only used to assess the critical duration for the 1% AEP Rainfall Event to compare to AR&R 1987 temporal patterns, application of preburst to the rainfall was out of scope; • Climate change assessment was completed in accordance with DERM, DIP and LGAQ Inland Flooding Study (2010), in line with other flood studies within Mackay region; • Hydrologic and hydraulic modelling is based on methods and data outlined in Australian Rainfall and Runoff (AR&R) 2016 were used for only the 1% AEP Rainfall Event. • The 2016 design rainfall intensities were applied to the 1987 AR&R temporal pattern for all storm intensities for the Basecase and mitigated case; • Climate change • The hydraulic models have not been calibrated as the model was updated based upon an already calibrated model. However spot heights recorded from the February 2008 flood event have been compared to design storm events which are of a similar magnitude. • Any use which a third party makes of this document, or any reliance on or decision to be made based on it, is the responsibility of such third parties. AECOM accepts no responsibility for damages, if any, suffered by any third party as a result of decisions or actions made based on this document. • Where information has been supplied by the Client or other external sources, the information has been assumed correct and accurate unless stated otherwise. No responsibility is accepted by AECOM for incorrect or inaccurate information supplied by others. • The area between Crowley Drive and the carparks within the Mackay Base Hospital (particularly the eastern portions) has poorly defined pit and pipe infrastructure and may result in a flood extent that may not be normally experienced in the residential lots along Crowley Drive or within the hospital carpark. Australian Rainfall and Runoff (AR&R) section 10.4 outlines several fundamental themes which are also particularly relevant: • All models are coarse simplifications of very complex processes. No model can therefore be perfect, and no model can represent all of the important processes accurately. • Model accuracy and reliability will always be limited by the accuracy of the terrain and other input data. • Model accuracy and reliability will always be limited by the reliability / uncertainty of the inflow data. • A poorly constructed model can usually be calibrated to the observed data but will perform poorly in events both larger and smaller than the calibration data set. • No model is ‘correct’ therefore the results require interpretation. • A model developed for a specific purpose is probably unsuitable for another purpose without modification, adjustment, and recalibration. The responsibility must always remain with the modeller to determine whether the model is suitable for a given problem. • Recognition that no two flood events behave in exactly the same manner.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 4

• Design floods are a best estimate of an “average” flood for their probability of occurrence. 1.5.1 Interpretation of Results The interpretation of results and other presentations in this report requires an appreciation of the limitations in accuracy, as noted above. Unless otherwise stated, presentations in this report are based on peak values of water surface elevation, flow, depth and velocity. Using flood levels as an example, the peak level does not occur everywhere at the same time and, therefore, the values presented are based on taking the maximum value which occurred at each computational point in the model during the entire flood event. Hence, a presentation of peak levels does not represent an instantaneous point in time, but rather an envelope of the maximum values that occurred at each computational point over the duration of the flood event.

1.6 Report Structure The West Mackay Flood Study Report has been split into 2 volumes: • Volume 1 → Study methodology, results, findings and recommendations. • Volume 2 → Mapping of results associated with the Volume 1 report. The structure of this Volume 1 report is as follows: • Section 2.0 describes the characteristics of the local catchments including typical land use, rainfall characteristics and a summary of historical flood events. • Section 3.0 describes the data available for the development of the hydraulic model. • Section 4.0 outlines the hydrologic assessment approach. • Section 5.0 outlines the hydraulic modelling approach and presents the results of the modelling. • Section 6.0 presents the basecase design flood depths, levels and extents for the study area. • Section 7.0 presents the results of the investigation with the effects of climate change on discharges and modelled flood extents. • Section 8.0 provides a summary of the preliminary structural mitigation options. • Section 9.0 outlines the results of the tangible flood damages assessment undertaken. • Section 10.0 contains base and mitigated case flood damages results. • Section 11.0 summaries structural mitigation costs. • Section 12.0 identifies the sequencing of mitigation options. • Section 13.0 summarises the key finding of the study.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 5

2.0 Study Area and Key Characteristics

2.1 Study Area For the purpose of this study, West Mackay has been divided into two study areas, with Study Area 1 being a subset of Study Area 2 as shown in Figure 3. Study area 2 extends from the railway line on the western side of the Lagoons watercourse to Mackay Cemetery in the North East. It also extends from the southern bank of the Pioneer river out to Nebo Rd to the south and Holland St to the north. The hydraulic model, however, has been extended beyond Nebo Rd along the whole South Eastern side of the Study Area 2 so that model outflows are located sufficiently far enough away from area of interest. Study Area 1 is located within Study Area 2 and consists of the portion of the model that will include an assessment of proposed flood mitigation works and flood damages assessment. Its extent from south west to north east goes from the Botanic Gardens to Bridge Rd and from the north-west to south east it extends from the urban streets immediately adjacent to Mackay Base Hospital out to Holland St and as far as parts of Mogford Street and Barton Street in the south east. Study Area 1 is shown in more detail in Figure 2. The extent of the West Mackay model is approximately 570 ha and is shown in Figure 3.

Figure 2 Catchment Characteristics and Topography – Study Area 1

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 OL D F OU LD EN RO AD P ROPOS D ED ROA A D O R www.aecom.com E V O R G N VIC A TORIA M S B TREET H ru TA i L g c TY h e R O w A D ay

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T K M H N E A E C E I G O S M T R H I T D T T IL N IMM R T N L OCK S I ST E O S T REET N E N T E M A T R E M E R E T W T S O B N O T L U KL INGNE T O R STR E B T EET E T E R E E T E R S T R S T N T T S L E E O W S D E E E E V R P B N U R T M B U A S DENNIS T E L T STR O K E H EET S H R D L E E C T E N A R A Data sources: Y T L R S S G R D T Base Data: (c) 2017 Qld Gov R N R A N E E T T A W CANNAN STREE K T A E E E F T IT E E F X U G A R R E N E T T D NELL L A O S S E DRIVE A R N E R G O S S E I T M S D T H P A A R O IL IM R B E MACKAY REGIONAL COUNCIL T T E R O S A O E D T N N P R E E IN TA R N G S T T T S O MINS S R N TER S T E TREE West Mackay Drainage Study E S T R T E T R E E T E U T L G A L P N E O D C N S D A L T O D H D E O L T S E R O E E IN K I S I E C Y N V R F O B N E Catchment Characteristics and E R U E S I N T C T O S R K R T E C E E O R T U E T D R A T T E E Topography - Catchment Extent R S R T A R A E T I M TROG B R A P V O T R T LB E M G E A R Y ST C A E N IE T E E REE S N B T W HA P R A P E D E N A R T A E R MC D O M C IN T LEN R M I S N R NAN A N C O T K S ST P D T H W U S RE L E C L R ET A O O E A C S N E T PROJECT ID 60589930 E O T U E L R T L Figure W R R A E T T C P E I E ATT C ON Pe T C STRE CREATED BY Reitanod a E L ET k D IN O ow T U n C D s A G A E R O S M O T T R T S 11/09/2019 C I U LAST MODIFIED H PE E O R E A Y i A T g K D F E S T Y h E w OWN F P E R ay S H R V E R C E IG E T HW T L E O O P A J T P E Y S A N B C C L U M LE v01 B R M VERSION: E O A R ENTS 03

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2.2 Catchment Characteristics The suburb of West Mackay is bounded by the Pioneer River to the north-west and the railway line to the south-west. The catchment drains to the north east between the Mackay Cemetery and the Bruce Highway, and overland to South Mackay. The storm water network also contains several discharge locations to the Lagoons watercourse. The catchment boundary and topography is shown in Figure 2 and Figure 3. The elevation of the residential area of West Mackay varies between 6 m AHD and 12 m AHD. The catchment drains to low-lying undeveloped areas to the north-east which vary in height between 3.5 m AHD and 5 m AHD. The topography is generally very flat with nominal slopes in the order of 1 on 600 to 1 on 1000 towards the east. The West Mackay area has been developed since approximately the late 1940’s. The older housing stock is generally low-set (habitable floor elevations approximately 1 metre above ground) or high-set homes with a habitable floor level approximately 2 metres above ground level. The more recent housing stock (circa 1970 and later) is generally a slab-on-ground construction. The more recent developments on the western side of Lagoon watercourse are predominately urban-residential, the northern parts of which have kerb to kerb bitumen and a pit and pipe system. The southern sector has grass swales and limited pit and pipe systems. The northern area is also subject to riverine influences. Study Area 1 which will include flood mitigation options is wholly urbanised, consisting of residential properties on rectangular gridded streets constructed in the “old style” with road crown levels above the footpath. The larger study area, while mostly consisting of residential housing also includes the Mackay Base Hospital, St Francis Primary School, Mackay Regional Botanic Gardens and West Mackay State School.

2.3 Climate Characteristics The study area is situated on latitude of 21º South, approximately 250 km north of the Tropic of Capricorn and within 6 km of the coast. As a result, the catchment experiences a tropical coastal climate. The climate is dominated by summer rainfalls with heavy falls likely due to monsoonal rains, severe thunderstorms and occasionally from tropical cyclones. Heavy rainfall is most likely to occur between November and April with most of the flood events occurring in the months of December to March. 2.3.1 Rainfall Regime The closest daily rainfall station to the study area is the Mackay Aero Meteorological Station, which is located approximately 3 km from West Mackay. Based upon the statistics provided for this station, West Mackay has a mean annual rainfall between 1500 mm – 1600 mm. The highest mean monthly rainfall of 339 mm occurs in February. The highest and lowest annual rainfall totals recorded at the Mackay Aero Meteorological Station are 3522.6 mm (in 1958) and 710.8 mm (in 2001), which shows a significant variation in annual rainfall from year to year. The highest monthly rainfall of 1287.8 mm was recorded in February 1958. Highest daily rainfall of 510.8 mm was recorded on 12 January 1951. The following graph (Figure 4) shows the distribution of the mean monthly rainfall throughout the year at the Mackay Aero club Meteorological Station.

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Figure 4 Mackay Aero Meteorological Office Rainfall Statistics (BoM, 2019)

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3.0 Available Data

3.1 General Available data relevant to the drainage analysis and design consisted of: • Previous drainage studies for the area (reports only) from MRC including: - West Mackay Drainage Study (Ullman & Norman Pty Ltd, 2003); • Topographical data in the form of aerial LiDAR survey (MRC, August 2015); • Terrestrial LiDAR (MRC, February 2019); • Aerial photography (MRC, 2017); • Stormwater network survey (MRC, April 2019); • GIS land use and boundaries dataset (MRC, November 2018); • WRM CBD TUFLOW model (WRM, January 2019); • Bakers Creek South Stormwater Model (AECOM, December 2018); • Spot heights for observed flood levels during the February 2008 event (MRC, October 2018) • Design drawings of proposed stormwater mitigation works (MRC, 2016). Each of these is described in more detail in the subsequent sections.

3.2 Previous Reports 3.2.1 West Mackay Drainage Study (Ullman & Norman Pty Ltd, 2003) The West Mackay Drainage Study was undertaken by Ullman and Norman for MRC in 2003 to provide options and costs for upgrading the drainage system in the area bound by Lagoon Street, Bridge Road, Hume Street and Holland Street. The study noted that uncontrolled overland flow through properties to the north of the study area resulted from the existing stormwater network surcharging. It suggests redirecting flows to the Lagoons area to the south. Two options were proposed. The first option was to upgrade the pipe system to carry 5 year ARI flows by extending the pipe network north of Donaldson Street and drainage outlets into the Lagoon opposite Jackson Street and McKenzie Street. Flows greater than 5 year ARI will continue to follow pre-existing flow paths and cause nuisance flooding. The study concludes that this option would address complains from the Study Area including those near the bend in Mogford Street. The second option called 50 year ARI would provide trunk stormwater culverts along Holland St south of Donaldson and along Chataway and Donaldson streets west of Holland Street to McKenzie Street. The area north of Donaldson Street would have 5 year ARI capacity. This option would require construction of new outlets to the Lagoon opposite Jackson, Mackenzie and Holland streets. The study concludes that the major advantage of this option is that flow would be directed away from the drainage problem areas that occur north of Bridge Road and around the Fourways intersection. However the study was not able to provide a quantitative estimate of this advantage in relation to the wider drainage network.

3.3 Rainfall Data Rainfall data was extracted from the Bureau of Meteorology (BoM). The 2016 Intensity-Frequency- Duration (IFD) design rainfalls were used as they are the most up to date information available as at 28/03/2019 as shown in Table 2.

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Table 2 BOM 2016 IFD Design Rainfall Depth (mm) Annual Exceedance Probability (AEP) 50% 20% 10% Duration 1 EY 5% AEP 2% AEP 1% AEP AEP AEP AEP 5 min 10.7 12.0 15.9 18.4 20.9 24.0 26.3 10 min 17.6 19.6 25.9 29.9 33.8 38.7 42.3 30 min 32.9 36.7 48.5 56.3 63.6 73.1 80.1 1 hour 44.9 50.5 67.7 79.0 89.9 104 114 2 hour 59.2 67.3 92.3 109 125 146 162 3 hour 69.0 79.1 110 131 152 178 198 6 hour 89.5 104 150 181 211 252 284 9 hour 104 122 179 218 257 310 352 12 hour 116 137 203 249 295 360 411 18 hour 136 160 241 299 359 443 511 24 hour 151 179 272 340 411 512 595

3.4 Tidal Data Tide data was sourced from Maritime Safety Queensland, 2019 Semidiurnal and diurnal tidal planes (see Appendix A) for the Mean High Water Springs (MHWS) and Highest Astronomical Tide (HAT).

3.5 Topographical Data The topographical information used for the West Mackay Drainage Study project was provided by MRC in the form of LiDAR survey, which was undertaken in 2015 by MRC. The LiDAR points were used to generate a base Digital Elevation Model (DEM) with a grid spacing of 1 m. There was no metadata provided with Lidar indicating vertical and horizontal accuracy. 3.5.1 Aerial Photography Aerial photography of the West Mackay region was supplied by MRC. The dataset was supplied as a single mosaic image which covers the extents of the study area. The imagery was captured in March 2015 at a resolution of 10 cm pixels.

3.6 Event Recorded Data 3.6.1 2008 Flood Levels Recorded spot heights for the February 2008 storm were used to compare against design events having similar expected frequency of occurrence. These heights were not used for model calibration since the model had already been calibrated and the scope of this study was simply add more of the storm water network and to extend the model boundaries. A comparison of these heights with the 200yr and 500yr design storms is outlined in 5.4.1

3.7 Existing Stormwater Drainage Infrastructure 3.7.1 Pipe and Pit Network Details MRC provided survey of the stormwater network in the West Mackay study area. This consisted of pit and pipe sizes and invert levels. The survey information was digitised using QGIS for application to the TUFLOW hydraulic model. Where invert level, slope, pit types or pipe diameter were missing, the following assumptions were made: • All upstream invert levels are higher than downstream invert levels (i.e. no pipes negative grade pipes) with no fall across pits.

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• Minimum cover of 600 mm, where practical. • Upstream pipe diameter (or equivalent size attribute) was matched to downstream pipe diameter. • Pit types not provided was used based on aerial imagery or street photo where available, if no imagery was available pit types was assumed based on surrounding pit types. Assumptions on pipe diameter and invert levels were made primarily for small pipes along Jackson St, along parts Lagoon St adjacent the Botanic Gardens, and around Crowley Drive. Pit invert levels were taken from Lidar elevations lowered by 0.1 m. 3.7.2 Culverts MRC provided culvert information for the West Mackay study area. This consisted of culvert sizes and invert levels. The survey information was digitised using QGIS for application to the TUFLOW hydraulic model. Where invert level, slope, pipe diameter or inlet and outlet information was missing, the following assumptions were made: • Inlet and outlet levels and locations were based on LiDAR information; • Minimum cover of 600mm, where practical; • Culvert sizes were based on surrounding culverts of similar open channel size.

3.8 Proposed Stormwater Drainage Infrastructure MRC provided detailed design drawings for the proposed stormwater drainage infrastructure with pit locations and pipe length, sizes and invert levels. This data was used to assess the mitigation scenarios with the hydraulic model.

3.9 GIS Data GIS data provided by MRC included cadastral boundaries, road lines, railway lines, aerial imagery and planning zones. This information was provided in the form of ESRi shapefile (.shp) and .ecw image files.

4.0 Hydrologic Assessment

4.1 Overview In order to estimate peak flood levels, flood extents and flood risk across the study area, a hydrologic assessment was undertaken to estimate flood flows resulting from local catchment design rainfall events.

4.2 Adopted Methodology Hydrologic inputs to the hydraulic models were applied using the direct rainfall approach. The direct rainfall method involves the application of rainfall directly onto the 2D model domain with TUFLOW. The rainfall depth in a particular timestep is applied to each individual hydraulic model grid cell, and the 2D model calculates the runoff from this particular cell. For a closed catchment without external inflows, this method bypasses the need to construct a separate hydrological model. Hyetographs for each design storm were created to represent the local catchment rainfall for the study area using 2016 BOM Intensity-Frequency-Duration (IFD) data. The rainfall excess was calculated by applying initial and continuing losses to the total hyetograph to represent infiltration and storage of runoff in surface depressions. Adopted initial and continuing loss values are discussed in Appendix A and shown in Table 27. The hyetographs were developed for a range of design events for magnitudes of 63% AEP up to the PMF (total of ten events).

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4.2.1 Design Rainfall Intensity-Frequency Duration (IFD) Data Design rainfall data was sourced from the Bureau of Meteorology (BoM) online AR&R 2016 IFD tool (http://www.bom.gov.au/water/designRainfalls/revised-ifd/?year=2016). Rainfall intensities up to the 24 hour storm duration for the 63%, 50%, 20%, 10%, 5%, 2% and 1% AEP are shown in Table 3 below. Table 3 Intensity Frequency Duration (IFD) Data for West Mackay (BOM, 2016)

Duration Intensity (mm/hr) (hr) 63% AEP 50% AEP 20% AEP 10% AEP 5% AEP 2% AEP 1% AEP 1 44.9 50.5 67.7 79.0 89.9 104 114 1.5 35.3 39.9 54.2 63.7 72.8 84.5 93.3 2 29.6 33.6 46.1 54.5 62.5 73.0 80.8 3 23.0 26.4 36.8 43.7 50.5 59.3 66.0 4.5 17.9 20.6 29.3 35.1 40.9 48.4 54.2 6 14.9 17.3 24.9 30.1 35.2 42.0 47.3 9 11.6 13.6 19.9 24.2 28.6 34.5 39.1 12 9.70 11.4 16.9 20.8 24.6 30.0 34.2 24 6.30 7.46 11.3 14.2 17.1 21.3 24.8 4.2.2 Temporal Patterns AR&R 2016 uses an ensemble approach to modelling temporal patterns. Rather than one temporal pattern there are a suite of ten patterns representing different temporal distributions of the design rainfall. Typically a value representing the median hydrograph would be chosen. As there was no hydrological model developed for this study the temporal patterns were assessed hydraulically. All ten temporal patterns were run for a range of storm durations. A flood envelope was then developed from the ten temporal patterns that represented the median value at given point for a given duration. This approach is discussed further in Appendix A. The 1987 temporal patterns for Zone 3 have been applied to the 2016 design rainfall intensities. Temporal patterns for the Wet Tropics from AR&R 2016 were used determine the critical storm duration for the catchment. The 1% AEP event was been modelled using both the 1987 and 2016 approaches for comparison. Temporal patterns for the Probable Maximum Precipitation (PMP) event were sourced from data provided with the Generalised Short Duration Method (GSDM) guidebook. 4.2.3 Areal Reduction Factors Areal reduction factors were not applied to the point rainfall sourced in Section 4.2.1. This provides both a conservative estimate of the design rainfall as well as a consistent approach to previous modelling undertaken for the Mackay area. 4.2.4 Probable Maximum Precipitation Event The Probable Maximum Precipitation (PMP) has been defined by the World Meteorological Organisation (2009) as ‘the greatest depth of precipitation for a given duration that is meteorologically possible for a given catchment. The PMP event results in a Probable Maximum Flood (PMF) event. This is a theoretical event which is very unlikely to ever occur within any given catchment. The PMF event is typically used in the design of hydraulic structures such as dams and to determine the maximum flood hazard extents. Its most common use is in design of dam spillways to minimise the risk of overtopping of a dam and minimise the likelihood of dam failure. Other than this practical use, it is also used to provide an indication of the largest floodplain extents expected within any given catchment. This data can be used by emergency management agencies in their understanding of and planning for flood events and the residual risk beyond the Defined Flood Event.

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The GSDM, as revised in 2003, was applied to derive estimates of PMP for short duration storms. The GSDM applies to catchment up to 1,000 km2 in area and durations up to 6 hours, which makes the method applicable to the West Mackay Flood Study which has a catchment study area of approximately 2.8 km2 and a critical duration of 2 hours. Due to the volume of rainfall for the PMP storm the critical duration for the PMF event was found to be a lower duration than what was identified for the other storm rainfall events. Using the methodology set out in the GSDM Guidebook (BOM, 2003) the following data for the PMP was determined: • The coastal GSDM Method is applicable as the catchment lies on the Queensland coast. • The Roughness (R), Elevation Adjustment Factor (EAF) and Moisture Adjustment Factor (EAF) and Moisture Adjustment Factor (MAF) were calculated as 0, 1.0 and 0.98 respectively. • PMP parameters were calculated as shown in Table 4. Table 4 Adopted PMP Parameters

Duration (hrs) Rainfall Total (mm) Rainfall Intensity (mm/hr) 1 467 467 2 597 299 3 668 223 6 836 139

The ARI of the PMP event was calculated as recommended in AR&R (Pilgrim, et al, 1987). For a catchment area of 5.72 km2, the PMP event is approximately a 1 in 10,000,000 ARI event.

4.3 Hydrologic Model Validation Traditional model calibration and validation was not completed for the West Mackay Drainage Study since the study involved refinement of a calibrated model. However a comparison of recorded levels from the February 2008 storm event to the 0.5% AEP and 0.2% AEP outputs was undertaken. This comparison is discussed in 5.4.1.

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5.0 Hydraulic Model Development

5.1 Overview An integrated one-dimensional (1D) / two-dimensional (2D) hydraulic model was developed to simulate flood behaviour within the study area. TUFLOW software (version Build 2018-03-AD) was used for all model simulations. This is consistent with other drainage studies undertaken for MRC.

5.2 Adopted Methodology This section of the report documents the development of the hydraulic model used to simulate piped drainage and overland flows within the catchment. A TUFLOW hydraulic model was produced with parameters as shown in Table 5. Table 5 TUFLOW model Parameters

Parameter West Mackay TUFLOW Hydraulic Model Completion Date July 2019 AEP’s Assessed 1EY, 39%, 18%, 10%, 5%, 2%, 1%, 0.2%, 0.5% AEP & PMF Hydrologic Modelling Direct rainfall on 2D grid IFD Input Parameters AR&R 2016, Refer Section 4.2.1 Hydraulic Model TUFLOW Version 2018-03-AD-iSP-w64 Software Grid Size 4 m DEM (year captured) LiDAR (2015) Roughness Spatially varying and depth varying standard values (Refer to Table 26) Eddy Viscosity Smagorinsky Model Calibration No model calibration undertaken. The model was built upon an already calibrated model. Downstream Model Height varying discharge based on catchment slope (Manning’s equation Boundary based rating curves). Refer to Appendix A

A static tidal boundary (HT) using the level for Mean High Water Springs (MHWS) was used for the model boundary on the Pioneer River. Timesteps HPC mode uses a varying time step for the 2d domain with a specified minimum time step of 0.8 seconds. 0.5 seconds was adopted for the 1d network. Wetting and Drying Cell centre 0.0002 m Depths Sensitivity Testing Continuing Loss ± 20% (Refer Section 6.3) Manning’s Roughness ± 20% (Refer Section 6.3) Climate Change to year 2100 (Refer Section 7.0) A visual representation of the model setup including the 2D model extent, downstream model boundaries and 1D network is shown in Figure 5. Direct rainfall was applied over the entire study area contained within the 2D model domain.

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G ´ l e n e GDA 1994 MGA Zone 55 l B l ru a ce 0 137.5 275 550 H C ig o hw n ay n Metres e c t 1:11,000 (when printed at A3) i o n

R o a d

LEGEND TUFLOW Boundary Condition HQ HT Study Area Hydrualic Model Extent ! 1D Pit 1D Pipe TMR Roads

y a w h ig H e c ru B

MACKAY REGIONAL COUNCIL West Mackay Drainage Study

Model Setup and 1D Network Map

PROJECT ID 60589930 Figure CREATED BY Reitanod P eak Dow LAST MODIFIED 10/07/2019 ns High way VERSION: v01 05 AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 5_Model_Setup_1D_Network_Map.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 16

5.2.1 Modelling Cross Drainage Structures Modelling parameters associated with the 1D network were consistent with the recommended energy loss values in the TUFLOW reference manual. Manning’s roughness coefficient values which were applied to the cross drainage infrastructure were consistent with aged concrete. The same assumptions were applied to existing case and developed case models. Roughness values used in . the models are listed in Appendix A. 5.2.2 2D Modelling Roughness Within the road reserve (including grass strips, shoulders, kerb channels and footpaths) the default road reserve roughness value was applied, which was consistent with previous modelling of the area. Roughness delineation is shown in Figure 6 and the roughness values used in the existing case model are presented in Table 26.

5.3 Critical Duration Assessment The critical storm duration for the study area was assessed by simulating the 60, 90, 120, 180, 270, 360 and 720 minute duration storms at the 1% AEP event in the baseline hydraulic model. Figure 7 shows the 1% AEP critical duration map for storms based on the 1987 temporal patterns and Figure 8 shows the critical duration map for storms based on the 2016 temporal patterns. The critical duration map shows a range of critical durations in the catchment area from 60 minutes through to 270 minutes in areas with significant flood storage. In order to reduce model runs a single critical duration was chosen. The 120 minute storm was selected as it is broadly representative of peak flood levels across the whole study area. In those areas in which the 120 minute storm was not critical the maximum Peak Water Surface Elevations (PWSE) was generally within 50 mm of both the 60 minute and 270 minute storm duration peak water levels. The critical duration storm event was simulated for the 39%, 18%, 10%, 5%, 2% and 1% AEP. Rarer storm events were analysed individually to determine their critical duration. The 120 minute storm was applied to both the 1% AEP with climate change and the 0.5% AEP event. The 0.2% AEP event, 0.2% AEP + Climate Change, and the PMF were found to have a critical duration of 60 minutes. Further discussion of the derivation of the critical duration can be found in Appendix A.

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GDA 1994 MGA Zone 55 0 100 200 400

Metres 1:8,000 (when printed at A3)

LEGEND Study Area Hydrualic Model Extent TMR Roads Material Residential OpenSpace & Recreational Areas Road Reserve Rural Residential Commerical/Manufacturing Open Water Railway Sugar Cane Dense Vegetation Medium Vegetation Light Vegetation Buildings

MACKAY REGIONAL COUNCIL West Mackay Drainage Study

Hydraulic Roughness Delineation

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T E E R T S E M T U E H E R T S H A R A S ´

SHAKES PEARE STREE C T GDA 1994 MGA Zone 55 EMETE ST RY ROA R D T T G EE E E l T E E 0 100 200 400 e E R R n R T T A T E e V S E S l E l N D R R a U R T E B E O S N C R F I ID N D Metres o G O n E S R n B A R I G e O G c A t D (when printed at A3) i DUN 1:8,000 o CAN S n TREET

R M o O a R d R IS O N S T R E E T PATHW GARRAW TA AY AY STREET IT STR EET LEGEND

T L L E O B E C Y E E R U D A B V T L T A I S L S O G Study Area R E T N D S N R L S H S E Y S U E T Y E E T N E R T S L N R T T E E TR G E E E E L W E T EE E O T R R T Hydrualic Model Extent N R S T E T S L C R L E D A Y O E E C A T O T N N E S Critical Duration N S E S C T T T T T R E E IO R E E E U E R N T R T 60 min Storm O T S R C S O N A H T N D T A A E O L E S IL L R K P T C G 120 min Storm S A J T S E A E M M R IL O T N H S E L 180 min Storm T S A P A N A L E U G L U E O T T D E T 270 min Storm E E R S T T R S E IE E Z T N T E E K E C R A T S M S C D H N A A E S LAN L F T DSDOW RO L E O NE R UN O R C OAD DABO S K UT H T B R R E ID T E G C E T H E E A S T R T A T R W S E A R E Y E T S D T IN P R E E P R E R T Y S T R E E T

E W N A A R L D PENELOPE STREET D R O H N T O A A N P N T L P S E D R E T A RE S O E R S T T S O P F E T TE N T O I E A OT S E S F T S RL T E F E I A R R E T D A H T R C E S G E R S E E O T R U R A T E S T D R N O S R N E A S S E T K W R T E O E O T R B

L A W L E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R S S R T S A M N T S R S A O D Y E T H U E R E P T N U E O E T D T S E D M O N M D A S R S Y T R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T E E R T T EE S TR R S E S H N C I T PK E O L H F T L E U E A R CR P T OWL S EYS R T OAD H E T E Y R S T R S O F E IS K D E M A IT O R H G A H F P A O T M R Data sources: E IL D E T S Base Data: (c) 2017 Qld Gov y R O T a T N R S S E w T E h N R T ig A E M E M H W T C e T c O G E u B IN E r W N R E T T B B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T D E D L A Y L U S O West Mackay Drainage Study O E R T I B T R F O E E B E E E R T T N T E S E T R E N T E O S S R P D T N S M U L Baseline Critical Duration Map O L E H K V T E U T A E H E C R G 1987 Temporal Patterns T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 E T E E Figure M S E E T IL N T T E T O E Reitanod T O R CREATED BY H N S T O P T S M E S R T I N R S E D 11/07/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 07 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 7_Critical_Duration_1987.mxd A3 size www.aecom.com

T E E R T S E M T U E H E R T S H A R A S ´

R M o O a R d R IS O N S T R E E T PATHW GARRAW TA AY AY STREET IT STR EET LEGEND

T L L E O B E C Y E E R U D A B V T L T A I S L S O G Study Area R E T N D S N R L S H S E Y S U E T Y E E T N E R T S L N R T T E E TR G E E E E L W E T EE E O T R R T Hydrualic Model Extent N R S T E T S L C R L E D A Y O E E C A T O T N N E S Cadastre N S E S C T T T T T R E E IO R E E E U E R N T R T Critical Duration O T S R C S O N A H T N D T A A E O L E S IL L R K P T C G 60 min Storm S A J T S E A E M M IL R N O T E H S T L 120 min Storm S A P A N A L E U G L U E O T T T D E E 180 min Storm E R S T T R S E IE E Z T N T E E K E C R A T S M S C D H N A A E S LAN L F T DSDOW RO L E O NE R UN O R C OAD DABO S K UT H T B R R E ID T E G C E T H E E A S T R T A T R W S E A R E Y E T S D T IN P R E E P R E R T Y S T R E E T

L A W L E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R S S R T S A M N T S R S A O D Y E T H U E R E P T N U E O E T D T S E D M O N M D A S R S Y T R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T E E R T T EE S TR R S E S H N C I T PK E O L H F T L E U E A R CR P T OWL S EYS R T OAD H E T E Y R S T R S O F E IS K D E M A IT O R H G A H F P A O T M R Data sources: E IL D E T S Base Data: (c) 2017 Qld Gov y R O T a T N R S S E w T E h N R T ig A E M E M H W T C e T c O G E u B IN E r W N R E T T B B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T D E D L A Y L U S O West Mackay Drainage Study O E R T I B T R F O E E B E E E R T T N T E S E T R E N T E O S S R P D T N S M U L Baseline Critical Duration Map O L E H K V T E U T A E H E C R G 2016 Temporal Patterns T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 E T E E Figure M S E E T IL N T T E T O E Reitanod T O R CREATED BY H N S T O P T S M E S R T I N R S E D 11/07/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 08 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 8_Critical_Duration_2016.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 20

5.4 Calibration and Validation Model calibration was not undertaken for the West Mackay Drainage Study TUFLOW hydraulic model as the study was built upon updating a previous TUFLOW model that had already undergone calibration. Verification was undertaken by comparison of 2008 flood levels to the 0.5% AEP. 5.4.1 Comparison of Results to 2008 Flood Levels The GIS results layers from the TUFLOW modelling were compared to the point level observations within the study area for the 2008 event that were provided as a shape file. This event was notionally greater than a 1% AEP. Levels have been compared to the PWSE for the 200 year ARI and 500 year ARI design event simulations. And empty field indicates no flooding in that location. In all the locations in which there is flooding in both the observed and design events the levels are within ±200mm of each other. However some areas inundated in the 2008 event are not covered by the flood extents of the 200 year ARI and 500 year ARI events. All 2008 flood points located south of Nebo Road (Bruce Highway) were excluded of the comparison as they are outside the study area boundary and area of influence, no pits and pipes were required to south of Nebo as it did not impact the study area. The locations of the observed points are shown in Figure 9. Table 6 Summary of Baseline Peak Water Surface Elevations and Critical Duration

Peak Water Surface Elevations (m AHD) Natural Location 200 year ARI 500 year Surface 2008 Event 120 min Storm 60 min Storm G0021 7.93 8.11 8.26 8.28

G0021B 7.93 8.28 8.15 8.16

G0019C 7.72 8.04 7.97 7.98

G0019D 7.81 7.94 7.89 7.90

G0018A 7.75 7.62

G0022 7.31 7.10

G0022A 7.00 7.23 7.18 7.21

G0023 6.58 6.81 6.86 6.87

G0027A 6.74 7.14 6.78 6.79

G0026 6.54 6.79 6.88 6.90

G0025 6.40 6.79 6.70 6.71

G0028A 7.91 7.71

G0028B 7.71 7.79

G0029 7.43 7.80 7.79 7.81

G0029B 7.32 7.78 7.79 7.81

G0030 7.85 7.90

G0031A 7.98 8.13 8.17 8.21

G0032A 8.05 8.17 8.23 8.27

G0016 7.10 7.16 7.24 7.27

WN41 10.01 10.10 10.09

WN44 7.13 7.22

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 21

Peak Water Surface Elevations (m AHD) Natural Location 200 year ARI 500 year Surface 2008 Event 120 min Storm 60 min Storm MR 17 5.76 6.73

WN40 9.78 9.82 9.89 9.92

WN42 10.89 11.25 11.24 11.26

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 PROPOS D ED ROA A OL D O D R F E www.aecom.com OU V L O DE R N G RO N AD A VICT M ORIA S TREET

TA L TY R O A D

T E E R ´ T S E BR Ma U T ckay - M CE EE Slade U HI R Poin H GH ST t Road WA ON GDA 1994 MGA Zone 55 Y RD XIT GO ET E STRE 0 137.5 275 550 DON GOR

B R U C Metres E

H I G MR 17 H W 1:11,000 (when printed at A3) T E A E Y R T E S X I H T A ALFRE R D STRE A ET S

G l e

n T

e E l T l S E E a T CEM T ET E R R ERY E LEGEND C E ROA R SH T E D E AKESP T T EAR S o T E E S E R STRE n R E T ET L D S n AV R E e B E R T R E c R N S O E P t ID U F Study Area i E N N o G I E WN41 O D G0023 n S R R B R O I A A G G T o D a DU E Hydrualic Model Extent d NC E AN STR T E R M ET E T O E T S

R R E R HYNE T ST T E Flood Levels 2008 IS REET N S R O T N A T E E

S R S P B ATH M E GA T WA T T Y G R A E I A R R R T S M AW TRE R E A E ET T E Cadastre Y E R O E S L C B S T T Y I

R C R EE T U L E A I T B T L L A T S E L O T T T E G0028A U S G U E O R R Y S IF R FIN J N D N T ST L R A T EE N E S S H S S R T V E M WN42 T T T O G I S R U R E R A T L R S E N T G0022A E D T E E N E E E E E G0022 G Y N T T T E R N L E S T G0028B I L L L A T E C W R E L O E E O T R T R R E T H N I T N E T T W N C U T S G0018A ON ST R E O T E E E O A E N ET E E C C E A R T L E T E R T R IO H S T L R T T I T S T S N A E S G S N L ORR S E T IS N D R P R R D STREE O O T L T E Y R A S E S T M E L D K A S T E I E C E L N A N S W A W M J R E T G0030 O O S L E J H A H T S N A E L T G E U E G0031A O R G0029B G0029 D T S G S C EORG E T H E ST I A TA REET Z E E Y N E F L E R G0032A E O K T R J R ET C S S O S TRE A D T H T N S M N R N R EVA LANDS R A E S E DOWN OUN L E O E E ROA DABO L T N T D UT O C T S H H E T A E R T R E T A T O E W K T E S E A E Y R E S E F R WN44 G0019C E T T D T R S N E I S E T E P R E T E H R P E S A I G0019D U T T L L S

WN40 E G T T T N E N E D E TREET O S S OPE S N T T H C ENEL A O R E P T N L E N I EE D C E M TR S F K T A V S O E G0021B B N E N R R T T I S OT S T G E D T ROA L T U G R D AR R E S E E H E E O R E T C E T S E R N E T T S y T T S a R E S T S R K G0021 w P E R D R E E E T E E O h R T A O g R S T N R i Y O R B H A H S R e T T W c R R S u E r E O D

B T W N L

I A PEN N N L STRE W ET E W T A K E T T R O E E E E E D T D R R T R R O E A T T A E S S D P E S E R S R M N D T M A O Y IA T S CO D U M N R MINO H P O E R CO E S E I URT N U N T A D D R T G O S PRAT T E N T ST S S E O REET T M T R L E A F L E R UL A G T Y LE G A S R L T CO O L R UR O B E E T T E H N A L T R Y T A S R T S E T T N O T E E K R R R S E IPPE N M Y E N S E E T TRE E I S R ET E S T S T H T T T N R T S CH R N S T E ARL U T E E MA O Y CO E D R E T UR E E R T E R T T T E S E

N M O BA T S NNISTE E IL R ST E REET R W ET T E S TR R S E S H N C KI T T P E E O L E B H F R LACK CROW L T T STR LEYS U S E EET ROAD A H E P T R K Y T E S S IT R E H M O IS O F D H G A A F R T M O A E IL R P E T D O T R DIMM T N S E OC S T T K ST S R E REET N T E E R M E R A E C E R T M E G T T S W T IN S O N N N B S O T T O W R L T E E U L I KLI B E O NGNER T B T B M STR E E EET E R T L T E R E E T Y E E S S R R N T T T T R S S E O E L E S E D E R P T N V T M U U S DENN T L T G A IS S O K E D TREE E H R H T T E E A N E C A R F L Data sources: R T F S U R CA T N A NNA Base Data: (c) 2017 Qld Gov S N D N W E E STR A K T R EE T E T R I S A E T T D G R N E T E R ELLA D N E R O S E E IVE A R N R T G T X O E S S E M P A L IL IM B A MACKAY REGIONAL COUNCIL T S O O R N D A E S T N T T H R T O O MIN E N STER West Mackay Drainage Study R E ST D N T S REET A I T O N R R G G E S U E T O L T L T E B E R A E E N P N R T O E T N E D E H S D T T A S O T O E E E E D R S R R IN K R E R IE I T N B Y T N V P S N E S Locations of 2008 Flood Levels E S A C C T T IO N L K R E C R O E T C G O E O E A E S T P U E T R E U R A R S M R T T C T B HA F S N E DR IE I R TROG A L V OLB PLA M A A Y STR W CE D B IC N M EET S R H A R MC O E C E LEN T D NA R N N O N ST T E W U IN RE WO E E R L ET ODMAN PARADE A R K E S C E T PROJECT ID 60589930 T L T O T L R U A Figure E R T C P E I E ATT G T C ON R T C STRE CREATED BY Reitanod E L ET Pe T O A IN O ak D M ow E S C D U ns Hi E V F IE E R ghw R E L T O R T ay PE E S 10/09/2019 AK T N M S U O A LAST MODIFIED DOW S O T B Y NS I R R HIGH T R N B C WA G E T Y A P E P O O L C T L U C A O A VERSION: v01 F C R CLE 09 C U T MENT F E R E S STRE JE T ET AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 9_2008 Flood Obsevations.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 23

6.0 Basecase Hydraulic Modelling

6.1 Overview Direct rainfall modelling uses a process whereby rainfall is applied to every model cell. Mapping of these results in their raw form would show that the entire model extent is wet. For this reason, areas where the maximum water depth is less than 100 mm were removed from the mapping. Note that these depths are not excluded in the computational scheme. Furthermore, areas where the flood extent was less than 64 m2 (4 grid cells), were removed from the result mapping. GIS mapping of the model results includes peak flood elevations, depths and velocities and can be found in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). The following sections present PWSEs and peak flows at key points of interest. Figure 10 shows the cross-sections at which the peak flows were extracted. The locations of the key points at which PWSEs were extracted are shown graphically in Figure 11.

6.2 Basecase Peak Flood Depths, Extents and Velocities Maps 1 to 30 within Volume 2 show the maximum flood depth, extents and velocities for the 1EY, 39% AEP, 18% AEP, 5% AEP, 1% AEP, 0.5% AEP, 0.2% AEP and PMF basecase events respectively. The observed results for each of these scenarios are described further in the following sections.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 www.aecom.com

T E E R T S E M T U E H E R T S H A H R A e u S v m A C r eS eme te t ter e H _4 y e u ´ tr m S e SHAKES S PEARE t STREE _ C T GDA 1994 MGA Zone 55 3 EMETE ST RY ROA R D T T G EE E E l T E E 0 100 200 400 e E R R n R T T A T E e V S E S l E l N D R R a U R T E B E O S N C R 2 F I ID N D Metres o G _ O n E t S R n B A R I G e O S G c A e t D (when printed at A3) i DUN 1:8,000 o m CAN S n u TREET

R H M o O a R d R IS O N S T R E E 3 T PATHW GARRA _ T AY WAY STREE d AIT ST T R REET e LEGEND H g 2 T L d L _ u i E O B r m r E C Y E T R U D A B E B T L T C D e S L S O A Study Area E E T N G r y R S J S N R LE e T a S H E S Y o l S t E S U T w c T T N E R T S C S k N E R T T E E TR G l w R A E E E E E E L e O M s E T E E o R T R R Hydrualic Model Extent N y r W O o T S T T E L H n S T S L D E T E R L C Y S I E D A r D Z E Y C _ R O t N T E A E N O 3 IV T K S Discharge Lines N E E N S D C A E S T C T T o M E T T R E u E IO R E E H R N U E R g T Cadastre O T T l o S R C S a O C l N A H N s la A D T r O S L A o S n L L w K t d I P C M G Study Area 1 l A S e J T a E t y E c M D k IL R N 2 T e E r S n _ S L t t z A P A N A S L ie E S U G d L n U S E O 2 y T o t T s D _ lo E d S k L T c R R H E a o e E J l g T 2 la d _ n ri e d S i B C z T S H E A n E t_ E S LAN e R F T DSDO R T 2 E O WNE R OUN M k S R C OAD DABO c S t K UT D T B a a N R S R c A E r ID L T E G C k M L E T e H O E f E A e S T n H R e T A T a R W z S E A i R h E Y e E c T S S D T IN S P R t E E _ P R E 3 R T Y t S T S R E n E o T s d E W l 2 d N A A R a _ L D PENELOPE STREET t R R n H S e T O A o g N P N T n P S E R d E T A RE D o O i E R S T r T S s P F E T TE d F O B I E A OT l E S F T S RL R E I A a G T D A CH n U E R S S E O o O R A T N T D R D S S E T R S E E K T E O T O D R O B D N t A A S LD O S

R d O r N

S S o T D f R E N g E A o T L A W L M E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R S S R T 3 S A M N T S _ R S A O t D Y E T H U E R E P S T E N U n O E T D o T S s E d D l M a O N M n D A S R o S Y T D R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T t E E S R ET y T E l S R t R ST e E S l H l C IN T K a E P L O F T H G E L E U R CR PA T OWL S EYS R T OAD H E T E Y R S T R S s O s F E a IS D p A y K M E O R B I G A T F P y H O k T H R Data sources: A M E M D E S Base Data: (c) 2017 Qld Gov R IL T T T R S O E N E N S T A T M R M E C W E T O T G E B IN E W N R E T T B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T y E D L a Y L U S O West Mackay Drainage Study w E h T I B T R F ig E E E H E T e R T c T E u S E T r R E N T E B O S S R P D T N S M U L Model Key Points of Interest O L E H K V T E U T A E H E C R G Discharge Cross-Sections T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 D E T E E Figure A M S E E T O IL N T T E R T O E Reitanod O T O R CREATED BY B H N S T E O P T N S M E S R T I N R S E D 11/07/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 10 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 10_Model Key Points of Interest - Lines.mxd A3 size www.aecom.com

T E E R T S E M T U E H E R T S H A R A S ´

R M o O a R d R IS O N S T R E E T PATHW GARRAW TA AY AY STREET IT STR EET LEGEND

T L E L B T E C O E Crow3 Y A E R U D T B E T L O A R S L S G Study Area E T N T S N R LE CROW S S H E S Y LEY D S E S U E T S RIVE A T T N R T N E R T T E E TR G M E E E E E E L O E T E E R T R R Hydrualic Model Extent N Crow4 Crow2 H T S T T E T S T S L E R L I E D A Z Y O E E C A N T O T Jack1 E N ! N E K S Key Points N S C E S A C T M T T T R E IO R E E U E R N T T Cadastre O Jack2 S R C O N A H D T A A Doug1 L L Crow1 IL P G Study Area 1 M IL N Jack3 E Doug2 L A P Mack1 N A E U T L E E T E T R E T Jack4 S S D T N R Doug3 A E L E Mack2 L T O H

S C Holl1 H A Doug4 E S LA Mack3 F T NDSDO R E O WNE R OUND R C OAD ABO T S K UT E T B E C R R R H E ID T A T E G S T E T A E E N W S O A R T S Y T R K S Mack4 Holl2 S E C T R E A R E T J E Mack5 E D T IN P E P R R Holl4 Holl3 Y S T Mack7 Mack6 R E E Holl6 T

E W N A A R L D PENELOPE STREET Lag1 R Holl7 H T O A Holl5 N P N T P S E R E T A RE O E R S T T S P F E T TE F O I E A OT Holl8 E S F T S RL R E I A G T D A CH U E R S S E O O R A T N T D R Mog1 S S E T R S E E K T E O Mog3 T O D R Mog2 O B D N A A LD O S O R N

S S Bart1 T D Mog4 R E N E A T

L A W L Lag2 Bart2 E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R Bart3 S S R T S A M N T Lag3 S R S A O D Y E T H U E R E P T N U E O E T D T S E Lag4 D M O N M D A S R S Y T R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T E E R T T EE S TR R S E S H N C I T PK E O L H F T L E U E A R CR P T OWL S EYS R T OAD H E T E Y R S T R S O F E IS K D E M A IT O R H G A H F P A O T M R Data sources: E IL D E T S Base Data: (c) 2017 Qld Gov y R O T a T N R S S E w T E h N R T ig A E M E M H W T C e T c O G E u B IN E r W N R E T T B B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T D E D L A Y L U S O West Mackay Drainage Study O E R T I B T R F O E E B E E E R T T N T E S E T R E N T E O S S R P D T N S M U L Model Key Points of Interest O L E H K V T E U T A E H E C R G Water Surface Levels T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 E T E E Figure M S E E T IL N T T E T O E Reitanod T O R CREATED BY H N S T O P T S M E S R T I N R S E D 11/07/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 11 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 11_Model Key Points of Interest - Points.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 26

6.2.1 Basecase Peak Water Surface Elevation Table 7 provides a summary of the baseline PWSEs at key interest points (refer to Figure 11) for 1EY, 39%, 18%, 10% 5%, 2% and 1% AEP events. Maps of the baseline PWSE across the entire model extent and intersection site are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). Table 7 Summary of Baseline Peak Water Surface Elevations

Peak Water Surface Elevation (m AHD) Natural Location 39% 18% 10% 5% 2% 1% Surface 1EY AEP AEP AEP AEP AEP AEP Bart1 10.43 10.65 10.72 10.73 10.73 10.74 10.74 10.75

Bart2 10.44 10.63 10.68 10.70 10.71 10.72 10.72 10.74

Bart3 10.52 10.75 10.77 10.78 10.78 10.79 10.79 10.80

Crow1 10.92 10.96 11.00 11.04 11.10 11.15 11.18 11.20

Crow2 10.54 10.83 10.96 11.07 11.12 11.16 11.19 11.21

Crow3 10.81 10.82 10.96 11.07 11.12 11.16 11.19 11.21

Crow4 10.82 10.89 10.92 11.00 11.05 11.09 11.12 11.16

Doug1 10.24 10.46 10.46 10.47 10.47 10.47 10.47 10.48

Doug2 10.37 10.50 10.51 10.52 10.53 10.53 10.53 10.54

Doug3 10.39 10.55 10.56 10.57 10.58 10.59 10.59 10.60

Doug4 10.37 10.56 10.57 10.58 10.59 10.60 10.60 10.61

Holl1 9.42 9.50 9.52 9.56 9.59 9.61 9.63 9.66

Holl2 9.50 9.56 9.58 9.63 9.67 9.70 9.72 9.75

Holl3 9.58 9.66 9.71 9.75 9.77 9.80 9.81 9.83

Holl4 9.69 9.78 9.82 9.85 9.88 9.90 9.91 9.94

Holl5 9.99 10.01 10.05 10.09 10.11 10.12 10.13 10.15

Holl6 9.87 10.01 10.04 10.08 10.09 10.10 10.11 10.12

Holl7 9.97 10.11 10.13 10.15 10.15 10.17 10.18 10.20

Holl8 10.21 10.41 10.41 10.42 10.42 10.43 10.43 10.43

Jack1 10.51 10.60 10.61 10.61 10.62 10.62 10.62 10.63

Jack2 10.69 -- -- 10.70 10.72 10.74 10.74 10.76

Jack3 10.68 10.78 10.79 10.79 10.80 10.80 10.81 10.81

Jack4 10.65 10.84 10.85 10.86 10.86 10.87 10.87 10.87

Lag1 11.45 11.50 11.51 11.51 11.52 11.52 11.52 11.53

Lag2 11.40 11.52 11.54 11.55 11.55 11.55 11.55 11.55

Lag3 11.47 11.62 11.62 11.62 11.63 11.63 11.63 11.63

Lag4 11.40 11.70 11.70 11.70 11.70 11.70 11.70 11.70

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 27

Peak Water Surface Elevation (m AHD) Natural Location 39% 18% 10% 5% 2% 1% Surface 1EY AEP AEP AEP AEP AEP AEP Mack1 9.84 10.01 10.02 10.05 10.06 10.08 10.09 10.10

Mack2 10.01 10.13 10.14 10.15 10.15 10.16 10.16 10.17

Mack3 10.06 10.19 10.21 10.22 10.24 10.25 10.26 10.27

Mack4 10.14 10.25 10.25 10.27 10.29 10.31 10.32 10.34

Mack5 10.01 10.37 10.38 10.40 10.42 10.43 10.43 10.45

Mack6 10.24 10.41 10.44 10.45 10.46 10.47 10.48 10.50

Mack7 10.56 10.65 10.66 10.66 10.67 10.67 10.67 10.68

Mog1 10.14 -- 10.17 10.30 10.35 10.38 10.39 10.42

Mog2 10.01 10.07 10.17 10.30 10.35 10.38 10.39 10.42

Mog3 10.03 10.04 10.17 10.30 10.35 10.38 10.39 10.42

Mog4 10.09 10.10 10.17 10.30 10.35 10.38 10.39 10.42

6.2.2 Basecase Peak Discharges The peak flow rates at key flowpaths within the study area were extracted for each of the Basecase events modelled.Table 8 provides a summary of the baseline peak discharges at key cross-sections (refer to Figure 10) for 1EY 39%, 18%, 10% 5%, 2% and 1% AEP events. Maps of the baseline PWSE across the entire model extent are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). Table 8 Peak Discharges at Select Locations for Basecase Design Events

Peak Discharges (m3/s) Location 39% 18% 10% 5% 2% 1% 1EY AEP AEP AEP AEP AEP AEP BridgeRd 0.64 1.37 2.36 3.19 4.16 5.16 6.68

BridgeRd_2 0.10 0.44 0.98 1.34 1.69 2.00 2.55

BridgeRd_3 0.06 0.11 0.15 0.19 0.19 0.19 0.23

Cemetery 1.28 1.75 2.41 2.96 3.59 4.10 5.02

CrowleyDr 0.09 0.12 0.15 0.17 0.21 0.21 0.35

CrowleyDr_2 0.00 0.00 0.00 0.00 0.01 0.08 0.18

CrowleyDr_3 0.14 0.21 0.30 0.35 0.35 0.32 0.35

DonaldsonSt_3 0.58 0.92 1.37 1.70 2.00 2.18 2.63

DonaldsonSt 0.20 0.29 0.46 0.57 0.67 0.78 1.03

DonaldsonSt_2 0.43 0.78 1.18 1.47 1.73 1.86 2.38

DouglasSt 0.11 0.16 0.20 0.23 0.28 0.29 0.34

GalletlySt 0.44 0.88 1.32 1.68 2.10 2.35 2.97

HollandSt 0.12 0.25 0.47 0.72 0.98 1.14 1.48

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 28

Peak Discharges (m3/s) Location 39% 18% 10% 5% 2% 1% 1EY AEP AEP AEP AEP AEP AEP HollandSt_2 0.30 0.46 0.82 1.18 1.55 1.82 2.39

HumeSt 0.10 0.22 0.49 0.76 1.05 1.20 1.75

HumeSt_2 0.25 0.38 0.56 0.68 0.78 0.85 0.98

HumeSt_3 0.81 1.31 2.08 2.75 3.58 4.21 5.38

HumeSt_4 0.21 0.45 0.82 1.21 1.65 1.99 2.64

JacksonSt 0.13 0.19 0.27 0.34 0.43 0.48 0.63

JacksonSt_2 0.00 0.01 0.09 0.22 0.37 0.45 0.75

LloydSt 0.25 0.56 0.89 1.64 2.54 3.76 5.09

Mackenzie_2 0.04 0.09 0.20 0.34 0.53 0.71 1.21

MackenzieSt 0.27 0.42 0.63 0.79 0.95 1.06 1.28

MackenzieSt_3 0.14 0.26 0.44 0.56 0.70 0.79 1.05

MkyBypass 0.07 0.09 0.17 0.24 0.33 0.33 0.42

MogfordSt 0.16 0.24 0.32 0.38 0.46 0.47 0.58

SchaeferSt 0.08 0.14 0.93 1.75 2.59 3.30 4.11

StreeterAve 0.11 0.13 0.14 0.14 0.17 0.21 0.24

6.2.3 Basecase Underground Network Capacity A summary of the basecase network capacity identifying the capacity of the network within West Mackay during the specified design storm for each event is provided in Table 9 and Figure 13 below. Table 9 Modelling Scenario – Basecase 1d Network Capacity

Total Length Pipes Flowing Full (m) Scenario (m) 39% AEP 18% AEP 2% AEP Basecase 1D 14384 1177 1751 4308 network 6.2.4 Basecase Property Impacts A summary of the basecase property inundation analysis for the West Mackay Drainage Study in Study Area 1 is provided in Table 10 below. Residential buildings and commercial buildings are considered impacted if flood waters are above the floor levels. Floor levels were provided by MRC from survey and Mobile Laser Scanning in the form of the Terrestrial Lidar Dataset, refer to Section 9.5 for information and Appendix C for building floor levels utilised in the model. Table 10 Modelling Scenario – Basecase Building Inundation Numbers in Study Area 1 ARI Event No. Residential No. Commercial Total No. Buildings Buildings Impacted Buildings Impacted Impacted 2 year 0 0 0

5 year 0 0 0

10 year 0 0 0

20 year 1 0 1

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 29

ARI Event No. Residential No. Commercial Total No. Buildings Buildings Impacted Buildings Impacted Impacted 50 year 1 0 1

100 year 1 0 1

It can be seen that building inundation numbers progressively increase as the flood magnitude increases. A diagram indicating the buildings inundated (water over habitable floor level) for each of the analysed local catchment events for this scenario are shown in Figure 14. 6.2.5 Hospital Stormwater Drainage Infrastructure The area between Crowley Drive and the carparks within the Mackay Base Hospital, particularly the eastern portions has poorly defined pit and pipe infrastructure and may show a flood footprint that may not be normally experienced in the residential lots close to Crowley Drive or the hospital carpark. The area of interest is shown below.

Figure 12 Crowley Drive – Lack of Pit and Pipe data within Hospital Precinct (1% AEP shown).

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T E E R T S E M T U E H E R T S H A R A S ´

R M o O a R d R IS O N S T R E E T PATHW GARRAW TA AY AY STREET IT STR EET LEGEND

T L L E O B E C Y E E R U D A B V T L T A I S L S O G Study Area R E T N D S N R L S H S E Y S U E T Y E E T N E R T S L N R T T E E TR G E E E E L W E T EE E O T R R T Hydraulic Model Extent N R S T E T S L C R L E D A Y O E E C A T O T N N E S Cadastre N S E S T C T T E T T R E E IO R E E R N U E R T Pipe Capacity O T T S R C S O N A H T N D T A A E O L E S IL L R K P T C G 1EY S A J T S E A E M M IL R N O T E H S 39% AEP T S L A P A N A L E U G L U E O T T D E T 18% AEP E E R S T T R S E IE E Z T T 10% AEP N E E K E C R A T S S C M H D A 5% AEP N A E S LAN L F T DSDOW RO L E O NE R UN O R C OAD DABO S K UT H T B R R 2% AEP E ID T E G C E T H E E A S T R T A T R W S E 1% AEP A R E Y E T S D T IN P R E E P R E R T Y S T R E E T

E W N A A R L D PENELOPE STREET D R O H N T O A A N P N T L S E D E T A RE S E R S T T S O F E T TE N T I E A T S E F T S LO E R T R F T I A R T E A CH E S R E E G E S T R U R T E S T R N O R N S E A S S E T K W R T E O D E O A T R O B R D D A E S O O R P O S R

D P

L A W L E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R S S R T S A M N T S R S A O D Y E T H U E R E P T N U E O E T D T S E D M O N M D A S R S Y T R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T E E R ET T E S R R ST E S H N C KI T P E O L T H F E L E U R CR PA T OWL S EYS R T OAD H E T E Y R S T R S O F E IS K D E M A IT O R H G A H F P A O T M R Data sources: E IL D E T S Base Data: (c) 2017 Qld Gov y R O T a T N R S S E w T E h N R T ig A E M E M H W T C e T c O G E u B IN E r W N R E T T B B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T E D L Y L U S O West Mackay Drainage Study T IE B T R F E E E E R T T T E S E T R E N T E O S S R P D T N S M U L 1D Network Capacity O L E H K V T E U T A E H E C R G T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 E T E E Figure M S E E T AD IL N T T E T O E Reitanod RO T O R CREATED BY H N S T O O P T B S M E S E R T I N N R S E D 11/09/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 13 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 13_1D_Network_Capacity.mxd A3 size www.aecom.com

T E G E A R R T R S A C E W S U V S L I A E L HUNTER STREET R Y N E D S N T S Y R T E E R L E E W T E O T R C ´

S C GDA 1994 MGA Zone 55 H A E F E R 0 50 100 200 O A S T T E R S E S E T T R E Metres E T T T R E U E 1:4,000 (when printed at A3) R O T C S H T N A O L S P K T C E A E J R T G S L E S N A E M M L L O IL A H N C T E L O A N T N N E E E E LEGEND C T R I T O S N S R A O L A T G Study Area D E U E O R D T S E M Hydraulic Model Extent U H

T Cadastre E E R T S IE Z 20yr | Properties Impacted N E K C A M 200yr | Properties Impacted T E E R T S PMF | Properties Impacted D N A L L O H Study Area 1

ROU NDA BOUT OAD NE R DOW ANDS L B R ID G E T R E O E A C R D H T A S T A R G W E A D le Y IN n S P e T l R l E a E C T o n n e c t io n R o a d

T EE TR E S OP EL EN P A N A D S O T N A A S L I D A S O S N T S R ET T E E R TR E E S E T T TE T E OT E RL R HA T C S F E R R T E G E N U E R S R A O T W N S S S T R K E O E O T R B

M O G F O R D S T R E E T

D A O R D A E L T S E E O X E P R O A T R N S P T D E N R E O R A B D T

S A S T R Y R T T U O E P E U E N E R D T S T T S R M E A E H T E N O T S Data sources:

L Base Data: (c) 2017 Qld Gov A G O O D N A S O T R R O B E E MACKAY REGIONAL COUNCIL E N T West Mackay Drainage Study G A L L E T L Y S T R E E T Base Case - Study Area 1 Building Inundation Locations

y a w h CH g ARLMA i Y COU H PROJECT ID 60589930 RT e T c Figure E u E r R Reitanod T B CREATED BY S S IN K LAST MODIFIED 11/09/2019 P O H L VERSION: v01 U 14 A P AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 14_Base Building Inundation Location Summary.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 32

6.3 Sensitivity Analysis 6.3.1 Hydraulic Roughness As the roughness values applied to the hydraulic model were based of previous studies and recommendations from AR&R, two sensitivity tests were run to simulate a 20% increase and decrease to the roughness values adopted for the study. These results were used to check if differences in the Manning’s ‘n’ values would have significant effects on stormwater runoff across the study area. The sensitivity modelling was undertaken for the 1% AEP event, for both the baseline and developed case scenarios. The maps of the hydraulic roughness sensitivity analysis results are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). In summary, the mapping shows that the results are not overly sensitive to the hydraulic roughness change over the area of interest. The changes are minimal (within 10 mm PWSE increase for 1% AEP ±20% Manning’s ‘n’), providing confidence in the results published as part of the study. 6.3.2 Continuing Losses As the loss values applied to hydraulic model were based on previous modelling experience within the area two sensitivities were run to simulate both a 20% increase and decrease to the continuing loss values adopted for the study. These rules were used to check if differences in the continuing loss values would have significant effects on stormwater runoff across the study area. The sensitivity modelling was undertaken for the 1% AEP event, in the baseline and mitigated case scenarios. The GIS results maps of the continuing loss sensitivity are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). In summary, the mapping shows that the results are not significantly sensitive to the hydraulic roughness change over the area of interest. The changes are minimal (within 10mm PWSE increase for 1% AEP ±20% losses), providing confidence in the results published as part of the study.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 33

7.0 Effects of Climate Change

7.1 General A suite of climate change literature is available, covering global, national and more localised state based climate change discussion and analysis. Whilst much of the literature states that, for Queensland, total annual rainfall is decreasing and rainfall intensity during rainfall events is increasing, there is comparatively little literature recommending actual values to adopt for these changes. The Queensland Climate Change Strategy (QLD Government, 2007) indicated that cyclone intensity is expected to increase by 2050 with cyclone associated rainfall expected to increase by up to 20-30%. The other recently published document which provides guidance on the adoption of climate change values, and also provides guidance on the use of these scenarios in development planning is the Increasing Queensland’s resilience to inland flooding in a changing climate: Final report on the Inland Flooding Study published by DERM, The Department of Infrastructure and Planning (DIP) and the Local Government Association of Queensland (LGAQ) in 2010. The DERM, DIP and LGAQ Inland Flooding Study (2010) were specifically aimed at providing a benchmark for climate change impacts on inland flood risk. Whilst Mackay is not considered to be an inland area, this document does provide guidance on the adoption of climate change scenarios for development planning. The study recommends a ‘climate change factor’ be included into flood studies in the form of a 5% increase in rainfall intensity per degree of global warming. For the purposes of applying the climate change factor, the study outlines the following temperature increases and planning horizons: • 2°Celsius by 2050; • 3°Celsius by 2070; and • 4°Celsius by 2100. These increases in temperature equate to a 10% increase in rainfall intensity by 2050, a 15% increase in rainfall intensity by 2070 and a 20% increase in rainfall intensity by 2100. In addition to impacts on rainfall, sea level rises are also commonly discussed in climate change literature. The most recent publication that relates to Queensland is the Queensland Coastal Plan (and more specifically the State Planning Policy Coastal Protection). The second document outlines sea level rises that should be considered when planning for development in coastal areas of Queensland. Table 11 details the projected sea level rise up to 2100. Table 11 Projected Sea Level Rise (SPP 3/11, 2012) Year of Planning Projected Sea Level Rise Period (m) 2050 0.3 2060 0.4 2070 0.5 2080 0.6 2090 0.7 2100 0.8

In addition to the Coastal Plan, the Australian Government Department of Climate Change and Energy Efficiency report Climate Change Risks to Australia’s Coast – A First Pass National Assessment for Australia (2009) identified that 1.1 m sea level rise by 2100 is a plausible value to adopt. Whilst this document is not a policy document, its recommendations should be considered.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 34

7.2 Adopted Approach Given the uncertainty in climate change and sea level rise projections, particularly with respect to changes in rainfall intensity, climate change sensitivity has been undertaken as part pf this study. The hydraulic model has been used to assess the impact of climate change that would be expected to occur in 2100 for the 1% and 0.2% AEP design events. Therefore an increase of 20% has been applied to the rainfall for these events. In addition to the increased rainfall, climate change has the potential to increase sea levels. A sea level rise of 0.8m is expected by 2100. The MHWS level at the downstream boundary has been increased by 0.8m to 3.15m AHD for the design events incorporating climate change effects. Due to the topography across the study area, this only had an influence along the Pioneer River bank and Lagoon area.

7.3 Hydraulic Model Results The sensitivity result maps are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2). The increase in rainfall causes an increase in PWSEs (maximum 70mm PWSE increase for 1% AEP) across the West Mackay study area. An increase in flooding of properties is seen along Mackenzie and Douglas Streets and extra ponding in the ovals of St Francis Xavier Primary School and Mackay West State School.

7.4 Planning Scheme Flood Mapping To inform the current planning scheme the adopted approach was completed in accordance with Sections 7.1 and 7.2, which includes a 20% increase in rainfall and increase in MHWS level at the Pioneer River boundary by 0.8m to 3.15m AHD. Maps X – Y contain the mapping results for the 0.2% AEP rainfall event with climate change.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report 35

8.0 Structural Mitigation Options

8.1 Overview Due to the very flat topography and grade of the land within West Mackay there is only limited opportunity to improve the capacity of the underground network for a majority of the study area. The urbanised area does not have a well-developed drainage network. The structural mitigation option that was assessed focused on improving this network where possible within Study Area 1. Figure 15 and Figure 16 provide an overview of the proposed upgrade to the stormwater drainage network within Study Area 1 assessed during this study. The assessed structural mitigation includes: A. The installation of a stormwater network on Mackenzie and Douglas streets that begins approximately halfway between Bridge Rd and Donaldson St and directs flow away from Bridge Rd. The network also includes part of Donaldson and Chataway streets and directs the flow out along Mackenzie St before connecting to the pre-existing pipe network on Lagoon St that discharges to the Lagoon area. B. The installation of a Stormwater network in Mogford St running from the intersection with Stoneham St to the intersection with Barton St. Flows will be directed out to Holland St and connected up with the drainage network in Lagoon St that discharges under the Botanic gardens into the Lagoon.

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37 5 R T C E T E P E R E T R S T T S N E E O E S P R M K T U C S H A C J IE R Z N E ´ 0 K 0 C 6 A M GDA 1994 MGA Zone 55 3 75 0 15 30 60 R CP Metres P C 5 (when printed at A3) R 2 1:1,500 0 5 5 R 4 C P

37 5 R P C C R LEGEND P 0 D O 5 N 4 A L Study Area T D E S E O R N P T S S T C R N E Hydraulic Model Extent O E R T S T E 3 K 0 E 7 C R A 5 T 5 J 7 S S R Cadastre A L C G U P 3 O 7 D 5 Proposed Pipe Upgrades R C P P Pipes with No Upgrades C R 0 5 7 D O N A L D S O N S T 3 C R H E 7 A E 5 T T 9 A W 0 R A 0 C Y S R P T R C E E T P P C T E R E R T 0 S P 5 N 7 O C S T K E C R E A R J T 5 S P R D 7 N A C C L 3 4 R P L 5 O 0 5 H R 2 C 5 P P C 37 R 5 5 7 R T 3 C E E P R T S F D E N R A G L U L S O O H N S T R E 5 5 E 2 T 2 D 5 G 5 O l N R e A C n R P T L e E D P l C E l C R S a P T O C R S N S o IE T n 0 Z R n 0 N E e E E c 9 K T t C io A n M R P o C a d R P 0 C 5 R 7 5 7 3

P C R 0 L 0 A G 9 4 O 5 O 0 N S R T C R E P E T

C H A T A W A Y S T T E R E E R E T P T T S E D C E N R A D R T L O S L N Data sources: O A 0 IE L Z H D Base Data: (c) 2017 Qld Gov 0 N S E O 9 K N C S A T R M E E T MACKAY REGIONAL COUNCIL 3 7 5 R West Mackay Drainage Study C P

T E E R Stormwater Trunk Drainage Upgrade T S D P N A C L L Structural Mitigation A R O 0 H 5 52 10 5 R C PROJECT ID 60589930 L A P Figure G O Reitanod O CREATED BY N S T R LAST MODIFIED 11/09/2019 E E T VERSION: v01 15 AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 15_Proposed Pipe Upgrades_A.mxd A3 size C H A T A W A Y S T R E E T 52 5 R www.aecom.com 52 CP 5 T E E R P R D T O C C S N A P IE L F R Z D E N S R 0 E O G K N U 0 C S S 9 A T P O M R T N T E C E S E E E T T R E R R E R P T E T 0 S T S C D R 5 N E A R 7 L D L IN 5 O P 7 H 3 ´

P GDA 1994 MGA Zone 55 C R 0 0 15 30 60 0 9 4 50 R Metres C P 1:1,500 (when printed at A3)

C H F A E T R A G W U A S Y O S T N T E S R E T E R R E T E P T T S E E D T C E N R A LEGEND R T L S L 0 IE O Z H 0 N E 9 K C Study Area A M Hydraulic Model Extent D O 3 N A 7 L D 5 S Cadastre O R N S T C R L E Proposed Pipe Upgrades A P E G T O O N T E S E Pipes with No Upgrades T R R T E S E D T P N A C L L R O 50 5 H 0 2 T E 1 5 E R R T C S R P E N R A W

L A G O O N S T 8 R 2 E 5 E R T 825 RCP CP

D O 8 N A 2 L D 5 S O R N P S C T R C P E E R T 5 2 8 8 2 P 5 C T R E R P E C 5 R C 8 T P 2 2 S 8 R D 5 N 0 A R L 0 L C O 6 H P P B A C R R T 50 O 0 N 7 1 S 5 T R 0 E E R T C P P 6 C 00 R R 0 C 5 P P 10 C R 4 5 5 7 0 3 R C P P C R 5 7 3 75 0 B R A R C T O P N S T R E 3 E 7 T 5 L A R G O C P O N P C S R T R E 0 Data sources: E 5 M T O Base Data: (c) 2017 Qld Gov 7 G F T O E R E D R S T T S R N E O E T D MACKAY REGIONAL COUNCIL

P C T West Mackay Drainage Study E E R R T 5 S M 7 A M H O 3 E G N F O O T R S D Stormwater Trunk Drainage Upgrade S T R E E T Structural Mitigation B

PROJECT ID 60589930 Figure CREATED BY Reitanod LAST MODIFIED 11/09/2019 VERSION: v01 16 AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 16_Proposed Pipe Upgrades_B.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 38

8.2 Design Peak Flood Depths, Extents and Discharges Maps contained in the Volume 2 report display the Mitigation Options results including flood depths, extents and velocities for the 1EY, 39% AEP, 18% AEP, 10% AEP, 5% AEP, 2% AEP, 1% AEP, 0.5% AEP, 0.2% AEP and PMF events respectively. 8.2.1 Mitigated Case Peak Water Surface Elevations PWSEs across the range of design events were extracted at key locations within the study area and summarised in Table 12. Maps of the mitigated case PWSE and Afflux across the entire model extent are available in the West Mackay Drainage Study – Hydraulic Analysis Report (Volume 2) (Maps 33-74). Table 12 Summary of Mitigated Case Peak Water Surface Elevations

Peak Water Surface Elevation (mAHD) Natural Location 39% 18% 10% 5% 2% 1% Surface 1EY AEP AEP AEP AEP AEP AEP Bart1 10.43 10.62 10.62 10.63 10.66 10.71 10.71 10.73

Bart2 10.44 10.60 10.61 10.62 10.65 10.68 10.68 10.70

Bart3 10.52 10.73 10.75 10.75 10.77 10.77 10.78 10.79

Crow1 10.92 10.96 11.00 11.04 11.10 11.15 11.18 11.20

Crow2 10.54 10.83 10.96 11.07 11.12 11.16 11.19 11.21

Crow3 10.81 10.82 10.96 11.07 11.12 11.16 11.19 11.21

Crow4 10.82 10.89 10.92 11.00 11.05 11.09 11.12 11.16

Doug1 10.24 10.43 10.44 10.46 10.46 10.47 10.47 10.47

Doug2 10.37 10.42 10.42 10.42 10.47 10.50 10.51 10.52

Doug3 10.39 10.43 10.43 10.43 10.45 10.54 10.56 10.58

Doug4 10.37 10.52 10.53 10.56 10.58 10.59 10.60 10.61

Holl1 9.42 9.49 9.51 9.53 9.55 9.57 9.59 9.63

Holl2 9.50 9.56 9.57 9.58 9.60 9.62 9.64 9.70

Holl3 9.58 9.65 9.65 9.66 9.67 9.72 9.72 9.77

Holl4 9.69 9.77 9.77 9.78 9.79 9.80 9.82 9.86

Holl5 9.99 ------10.00 10.05 10.08 10.10

Holl6 9.87 9.98 10.01 10.03 10.04 10.04 10.07 10.09

Holl7 9.97 10.09 10.10 10.11 10.12 10.12 10.13 10.14

Holl8 10.21 10.38 10.40 10.41 10.41 10.41 10.41 10.42

Jack1 10.51 10.60 10.61 10.61 10.62 10.62 10.62 10.63

Jack2 10.69 -- -- 10.70 10.72 10.74 10.74 10.76

Jack3 10.68 10.78 10.79 10.79 10.80 10.80 10.81 10.81

Jack4 10.65 10.84 10.85 10.86 10.86 10.87 10.87 10.87

Lag1 11.45 11.50 11.51 11.51 11.52 11.52 11.52 11.53

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Peak Water Surface Elevation (mAHD) Natural Location 39% 18% 10% 5% 2% 1% Surface 1EY AEP AEP AEP AEP AEP AEP Lag2 11.40 11.52 11.54 11.55 11.55 11.55 11.55 11.55

Lag3 11.47 11.62 11.62 11.62 11.63 11.63 11.63 11.63

Lag4 11.40 11.70 11.70 11.70 11.70 11.70 11.70 11.70

Mack1 9.84 10.00 10.00 10.03 10.05 10.07 10.08 10.10

Mack2 10.01 10.11 10.11 10.12 10.14 10.15 10.15 10.16

Mack3 10.06 -- -- 10.16 10.19 10.22 10.23 10.25

Mack4 10.14 10.24 10.24 10.24 10.24 10.26 10.28 10.31

Mack5 10.01 10.27 10.28 10.28 10.34 10.37 10.37 10.40

Mack6 10.24 10.35 10.35 10.36 10.38 10.41 10.43 10.46

Mack7 10.56 10.57 10.57 10.58 10.62 10.63 10.64 10.66

Mog1 10.14 10.13 10.14 10.14 10.14 10.14 10.17 10.29

Mog2 10.01 10.07 10.07 10.07 10.07 10.12 10.17 10.29

Mog3 10.03 ------10.13 10.17 10.29

Mog4 10.09 10.09 10.10 10.10 10.10 10.12 10.17 10.29

8.2.2 Mitigated Peak Discharges PWSEs across the range of design events were extracted at key locations within the study area and summarised in Table 13. Table 13 Peak Discharges at Select Locations for Mitigated Design Events

Peak Distances (m3/s) Location 39% 18% 10% 5% 2% 1% 1EY AEP AEP AEP AEP AEP AEP BridgeRd 0.57 1.24 1.97 2.72 3.56 4.41 5.81

BridgeRd_2 0.04 0.28 0.74 1.02 1.34 1.57 2.19

BridgeRd_3 0.06 0.11 0.15 0.19 0.19 0.19 0.23

Cemetery 1.28 1.72 2.40 2.96 3.59 4.04 5.01

CrowleyDr 0.09 0.12 0.15 0.17 0.20 0.21 0.34

CrowleyDr_2 0.00 0.00 0.00 0.00 0.01 0.08 0.18

CrowleyDr_3 0.14 0.21 0.30 0.35 0.35 0.32 0.35

DonaldsonSt_3 0.18 0.27 0.34 0.43 0.62 0.83 1.33

DonaldsonSt 0.14 0.21 0.30 0.36 0.41 0.48 0.63

DonaldsonSt_2 0.42 0.78 1.18 1.47 1.72 1.86 2.37

DouglasSt 0.08 0.12 0.17 0.20 0.24 0.26 0.32

GalletlySt 0.45 0.88 1.32 1.68 2.10 2.35 2.97

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Peak Distances (m3/s) Location 39% 18% 10% 5% 2% 1% 1EY AEP AEP AEP AEP AEP AEP HollandSt 0.11 0.23 0.39 0.60 0.87 1.04 1.37

HollandSt_2 0.27 0.41 0.55 0.67 0.96 1.16 1.77

HumeSt 0.10 0.23 0.49 0.76 1.05 1.20 1.75

HumeSt_2 0.25 0.38 0.56 0.68 0.78 0.84 0.98

HumeSt_3 0.84 1.31 2.07 2.78 3.57 4.12 5.37

HumeSt_4 0.20 0.45 0.82 1.21 1.64 1.98 2.62

JacksonSt 0.13 0.19 0.27 0.34 0.43 0.48 0.63

JacksonSt_2 0.01 0.03 0.09 0.22 0.37 0.46 0.75

LloydSt 0.25 0.49 0.63 1.01 1.92 3.09 4.44

Mackenzie_2 0.04 0.06 0.13 0.27 0.44 0.56 0.89

MackenzieSt 0.07 0.16 0.45 0.65 0.83 0.93 1.18

MackenzieSt_3 0.08 0.11 0.21 0.21 0.31 0.39 0.58

MkyBypass 0.07 0.09 0.17 0.24 0.33 0.33 0.42

MogfordSt 0.02 0.03 0.04 0.05 0.06 0.11 0.33

SchaeferSt 0.08 0.13 0.81 1.56 2.36 3.04 3.81

StreeterAve 0.11 0.13 0.14 0.14 0.17 0.21 0.24

8.3 Difference in Peak Water Surface Elevation Difference in PWSE across the range of design events were extracted at key locations with the study area and summarised Table 14. Table 14 Summary of Difference in Peak Water Surface Elevations (Base Case – Mitigated Case) PWSE Difference between Base and Mitigated Cases (mAHD) Location 39% 18% 10% 1EY 5% AEP 2% AEP 1% AEP AEP AEP AEP Bart1 0.03 0.09 0.10 0.08 0.03 0.03 0.02

Bart2 0.02 0.07 0.08 0.06 0.05 0.04 0.03

Bart3 0.02 0.02 0.02 0.02 0.01 0.01 0.01

Crow1 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Crow2 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Crow3 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Crow4 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Doug1 0.03 0.02 0.01 0.01 0.00 0.00 0.00

Doug2 0.08 0.09 0.10 0.06 0.03 0.02 0.01

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PWSE Difference between Base and Mitigated Cases (mAHD) Location 39% 18% 10% 1EY 5% AEP 2% AEP 1% AEP AEP AEP AEP Doug3 0.12 0.13 0.14 0.13 0.05 0.03 0.02

Doug4 0.03 0.04 0.02 0.01 0.01 0.01 0.00

Holl1 0.00 0.01 0.03 0.04 0.04 0.04 0.03

Holl2 0.00 0.01 0.05 0.07 0.07 0.07 0.05

Holl3 0.02 0.06 0.09 0.10 0.08 0.08 0.06

Holl4 0.01 0.04 0.07 0.09 0.09 0.10 0.07

Holl5 0.04 0.08 0.12 0.11 0.07 0.05 0.04

Holl6 0.03 0.03 0.05 0.06 0.06 0.04 0.03

Holl7 0.02 0.02 0.03 0.04 0.05 0.05 0.06

Holl8 0.02 0.02 0.01 0.01 0.01 0.01 0.01

Jack1 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Jack2 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Jack3 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Jack4 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Lag1 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Lag2 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Lag3 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Lag4 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Mack1 0.01 0.02 0.02 0.01 0.01 0.01 0.01

Mack2 0.02 0.03 0.03 0.01 0.01 0.01 0.00

Mack3 0.26 0.24 0.07 0.05 0.04 0.03 0.01

Mack4 0.01 0.02 0.03 0.05 0.05 0.04 0.03

Mack5 0.10 0.11 0.13 0.08 0.06 0.06 0.05

Mack6 0.06 0.09 0.09 0.08 0.06 0.05 0.04

Mack7 0.08 0.09 0.08 0.05 0.04 0.04 0.02

Mog1 0.00 0.03 0.16 0.21 0.23 0.22 0.13

Mog2 0.00 0.09 0.23 0.28 0.25 0.22 0.13

Mog3 0.07 0.20 0.33 0.34 0.25 0.22 0.13

Mog4 0.00 0.07 0.21 0.25 0.25 0.22 0.13

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8.4 Mitigated Property Impacts A high level estimate of the predicted above floor flooding property impacts, has also been conducted for the Scenario 1 Mitigated Case. The tables presented below are based on floor level data from MRC Terrestrial LiDAR dataset, discussed in Section 9.5. As noted in Section 6.2.4, the values shown in Table 15 and Table 16 represent the number of properties where flood level is above the estimated floor level for the given flood event and Figure 17 identifies the building inundation locations. Table 15 Basecase Property Impacts No. Residential No. Commercial Total No. Buildings ARI Event Buildings Impacted Buildings Impacted Impacted 2 year 0 0 0

5 year 0 0 0

10 year 0 0 0

20 year 1 0 1

50 year 1 0 1

100 year 1 0 1

Table 16 Mitigated Case Property Impacts ARI Event No. Residential No. Commercial Total No. Buildings Buildings Impacted Buildings Impacted Impacted 2 year 0 0 0

5 year 0 0 0

10 year 0 0 0

20 year 0 0 0

50 year 0 0 0

100 year 0 0 0

Table 17 present a comparison between the Basecase and Mitigated Case property impacts. A positive value shows that the number of properties where floor flooding has been reduced in the Mitigated Case, compared to the Basecase. Table 17 Difference in Property Impacts ARI Event No. Residential No. Commercial Total No. Buildings Buildings Impacted Buildings Impacted Impacted 2 year 0 0 0

5 year 0 0 0

10 year 0 0 0

20 year -1 0 -1

50 year -1 0 -1

100 year -1 0 -1

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8.4.1 Mitigated Case Underground Network Capacity A summary of the basecase and mitigated network capacity identifying the capacity of the network within West Mackay during the specified design storm for each event is provided in Table 18 and Figure 18 below. Table 18 Modelling Scenario – Mitigated Case 1d Network Capacity

Total Length Pipes Flowing Full (m) Scenario (m) 39% AEP 18% AEP 2% AEP Basecase 1D 16300 2348 2863 6759 network

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T E G E A R R T R S A C E W S U V S L I A E L HUNTER STREET R Y N E D S N T S Y R T E E R L E E W T E O T R C ´

T Study Area 1 E E R T S IE Z Cadastre N E K C A M 500yr | Properties Impacted T E E R T S PMF | Properites Impacted D N A L L O H

ROU NDA BOUT OAD NE R DOW ANDS L B R ID G E T R E O E A C R D H T A S T A R G W E A D le Y IN n S P e T l R l E a E C T o n n e c t io n R o a d

T EE TR E S OP EL EN P A N A D S O T N A A S L I D A S O S N T S R ET T E E R TR E E S E T T TE T E OT E RL R HA T C S F E R R T E G E N U E R S R A O T W N S S S T R K E O E O T R B

M O G F O R D S T R E E T

D A O R D A E L T S E E O X E P R O A T R N S P T D E N R E O R A B D T

S A S T R Y R T T U O E P E U E N E R D T S T T S R M E A E H T E N O T S Data sources:

L Base Data: (c) 2017 Qld Gov A G O O D N A S O T R R O B E E MACKAY REGIONAL COUNCIL E N T West Mackay Drainage Study G A L L E T L Y S T R E E T Mitigated Case - Study Area 1 Building Inundation Locations

y a w h CH g ARLMA i Y COU H PROJECT ID 60589930 RT e T c Figure E u E r R Reitanod T B CREATED BY S S IN K LAST MODIFIED 11/09/2019 P O H L VERSION: v01 U 17 A P AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 17_Mit Building Inundation Location Summary.mxd A3 size www.aecom.com

T E E R T S E M T U E H E R T S H A R A S ´

SHAKES PEARE STREE C T GDA 1994 MGA Zone 55 EMETE ST RY ROA R D T T G EE E E E E 0 100 200 400 l T e E R R n R T T A T E e V S E S l E l N D R R a U R T E B E O S N C R F I ID N D Metres o G O n E S R n B A R I G e O G c A t D (when printed at A3) i DUN 1:8,000 o CAN S n TREET

R M o O a R d R IS O N S T R E E T PATHW GARRAW TA AY AY STREET IT STR EET LEGEND

T L L E O B E C Y E E R U D A B V T L T A I S L S O G Study Area R E T N D S N R L S H S E Y S U E T Y E E T N E R T S L N R T T E E TR G E E E E L W E T EE E O T R R T Hydraulic Model Extent N R S T E T S L C R L E D A Y O E E C A T O T N N E S Cadastre N S E S C T T T T T R E E IO R E E E U E R N T R T Mitigated Pipe Capacity O T S R C S O N A H T N D T A A E O L E S IL L R K P T C G 1EY S A J T S E A E M M IL R N O T E H S 39% AEP T S L A P A N A L E U G L U E O T T D E T 18% AEP E E R S T T R S E IE E Z T N T 10% AEP E E K E C R A T S S C M H D A 5% AEP N A E S LAN L F T DSDOW RO L E O NE R UN O R C OAD DABO S K UT H T B R R 2% AEP E ID T E G C E T H E E A S T R T A T R W S E A R E 1% AEP Y E T S D T IN P R E E P R E R T Y S T R E E T

L A W L E O X T T A D A E E D A E E T R N R E IA E R D T T E N M R S S R T S A M N T S R S A O D Y E T H U E R E P T N U E O E T D T S E D M O N M D A S R S Y T R S L E T A G E R G A T E L E O L T E O T N L Y S S T B T T R R E A E E E R E R E T T T S O M T S N N IT N H C S U S HAR T D T LMAY R R T COU E E RT E E E E T R T T S N O S IL W T E E R T T EE S TR R S E S H N C I T PK E O L H F T L E U E A R CR P T OWL S EYS R T OAD H E T E Y R S T R S O F E IS K D E M A IT O R H G A H F P A O T M R Data sources: E IL D E T S Base Data: (c) 2017 Qld Gov y R O T a T N R S S E w T E h N R T ig A E M E M H W T C e T c O G E u B IN E r W N R E T T B B E S MACKAY REGIONAL COUNCIL E T S B R E R E N R T E O L S T T D E D L A Y L U S O West Mackay Drainage Study O E R T I B T R F O E E B E E E R T T N T E S E T R E N T E O S S R P D T N S M U L 1D Mitigated Network Capacity O L E H K V T E U T A E H E C R G T R S A F N D F E E U K N N IT T D G A O E E T E N R O S S R E T T G R R R PROJECT ID 60589930 E T E E Figure M S E E T IL N T T E T O E Reitanod T O R CREATED BY H N S T O P T S M E S R T I N R S E D 15/07/2019 IN E R N LAST MODIFIED G E T A T S L S A R T A R B VERSION: v01 E O W 18 E R A T T AECOM does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. AECOM shall bear no responsibility anythe shallor information.liability bearAECOM errors, for defects, faults, or no omissions does in in accuracymap using and their of anyat or displayed this it does risk. the warrant so completeness information not person AECOM own Filename: P:\605x\60589930\500_DELIV\502_Report\Figures\Figure 12_1D_Network_Capacity_develop.mxd A3 size AECOM West Mackay Drainage Study – Volume 1 Report 46

9.0 Tangible Flood Damages Assessment

9.1 Objectives As part of the West Mackay Drainage Study, a flood damages assessment has been undertaken to help quantify the financial burden borne by the community due to the local catchment flooding. An assessment of the saving in flood damages will also assist in determining the potential economic benefits of the proposed flood mitigation options. This flood damages assessment considers the financial impacts of flooding, including the costs associated with direct damages to property and infrastructure, as well as indirect costs associated with the disruptive impacts of flooding. The methodology used to assess flood damages, and the resulting estimates are described below.

9.2 Estimating Flood Damages Flooding can result in significant financial and social impacts on a community. A breakdown of the various types of flood damages is displayed Figure 19. Intangible flood damages, such as emotional stress and inconvenience, cannot be quantified as a monetary value, and have not been included in this flood damages assessment. Therefore, reference to flood damages within this report refers to tangible flood damages only.

Figure 19 Breakdown of Flood Damage Categories (DNRM, 2002) Tangible flood damages, or the anticipated cost to residents, businesses and local government infrastructure due to flooding, have been estimated using a standardised approach adopted throughout Australia. The approach estimates the tangible impacts flooding has on people, property, and infrastructure, such as flooding of a building and contents, the lost opportunity value associated with wages and revenue and flooding of transport and utility networks. These tangible impacts are estimated based on the depth, likelihood of flooding and type of building/infrastructure. A building’s estimated depth of flooding and its classification (single storey, high-set, double storey or units), determines the total estimated flood damage for that building. The direct flood damage is determined based on stage-damage curves, which relate building type, building area and flood depth to the monetary loss associated with the structure and contents damage. Indirect damages associated with lost opportunity value, i.e. wages and revenue and the cost of temporary relocation, are then estimated as an additional percentage for residential and non- residential buildings.

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The combined direct and indirect damages then represent the total damage to the building. For this assessment, infrastructure damages, such as water treatment plants and utility and transport networks, are then estimated as a percentage of the total residential and non-residential damage combined.

9.3 General Methodology Flood damages have been estimated through the application of stage-damage curves. These curves provide damage costs as a function of water depth, and are used to estimate direct flood damages for individual buildings based on the peak flood depth that the building experiences during a flood event. Indirect damages and infrastructure damage have been estimated as a percentage of the direct damage. The assessment has been undertaken using the results of hydraulic modelling of the West Mackay Catchment for the West Mackay Drainage Study. Details of the hydraulic modelling are discussed in the West Mackay Drainage Study – Volume 1 and Volume 2 (AECOM, 2018). 9.3.1 Council 2018 Stage-Damage Curves MRC engaged WRM Water & Environment as part of the Mackay Floodplain Management Plan (2018) to undertake a review of flood stage-damage curves and develop curves specific to properties within the Mackay Region. This investigation was intended to provide the most accurate and up to date curves for use in flood damages assessments across the Mackay Region. The Council 2018 Stage- Damage Curves were provided by MRC for application to the West Mackay Drainage Study and have been developed using the following methodology (WRM, 2018): “Flood stage-damage curves (flood damage curves) relate the depth of flooding at a property to the cost of flood damage. The underlying data in the existing flood stage-damage curves in Australia is generally quite dated. Therefore, a new property damage survey was undertaken to derive locally representative stage-damage curves for the predominant residential and commercial property types identified in Mackay. The survey was conducted by an experienced valuer (from VASA valuers) visiting and physically inspecting the selected properties and estimating potential internal, external and structural damages at different depths of flooding using the valuation survey method. The survey also captured general property information on size, style, age, construction material, ownership, etc. The Mackay damage survey was conducted on 26 properties, 20 of which were residential and 6 of which were commercial properties. The properties for survey were selected from volunteers across Mackay. Comprehensive property damage assessment forms were designed and used to capture the specific data required for the derivation of stage-damage curves for the surveyed property types. The data collected for Mackay properties was supplemented with an additional 96 property surveys (66 residential properties and 30 commercial properties) that were conducted by WRM and VASA for the Brisbane River Strategic Floodplain Management Plan (BRSFMP) in May and June 2017. The methodology for the BRSFMP property survey was consistent with Mackay property survey. It was found that the shape and magnitude of the stage-damage curves developed from the Mackay residential data was consistent with the Brisbane data and therefore a combined dataset was considered suitable. There were some differences in the magnitude of the commercial stage-damage curves, however this was overcome by adopting value classes one class lower for the regional (Mackay) commercial properties when compared to the Brisbane commercial properties for higher value class enterprises. The flood stage-damage curves are suitable for flood damage estimation on a regional scale and are not appropriate for estimation of flood damages on an individual property basis.”

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9.3.2 Alternative Approaches Several other approaches for estimating residential flood damages and stage-damage curves have been applied in Australia, including those by the Victorian Natural Resources and Environment, Risk Frontiers, WRM (for Sunshine Coast Regional Council) and O2 Environmental (for Ipswich City Council). While these approaches follow the same general approach as the Council Stage-Damage Curves as outlined in Section 9.3.1, they use different estimates for stage-damage curves or consider damage types differently. A summary of literature relevant to these approaches is provided below. These provide detail on these alternative approaches. • Department of Infrastructure, Planning and Natural Resources (DIPNR) (2004) “Floodplain Management Guideline No 4 Residential Flood Damage Calculation”, Department of Infrastructure, Planning and Natural Resources, New South Wales Government, February 2004. • Middelmann-Fernandes, M.H. (2010) “Flood Damage Estimation Beyond Stage-Damage Functions: an Australian Example”, M.H. Middelmann-Fernandes, Geoscience Australia, Canberra, Australia, 2010, Journal of Flood Risk Management. • Department of Natural Resources and Water (2002) “Guidance on the Assessment of Tangible Flood Damages”, Department of Natural Resources and Water, Queensland Government, 2002. • O2 Environmental (2012) “Stage Damage Functions for Flood Damage Estimation – Interim Functions for 2012”, Prepared for Ipswich City Council, April 2012. • Sunshine Coast Regional Council (SCRC) (2010) “Estimation of Tangible Flood Damages (Maroochy River, Mountain Creek and Sippy Creek Catchments)”, Sunshine Coast Regional Council, April 2010. • Smith, D.I. (1994) “Flood Damage Estimation – A Review of Urban Stage-Damage Curves and Loss Functions”, DI Smith, Centre for Resource and Environmental Studies, Australian National University, Canberra, Australia, July 1994, Water SA. • WRM Water & Environment (2006a) “Stage-Damage Relationships for Flood Damage Assessment in Maroochy Shire”, WRM Water & Environment Pty Ltd, June 2006, prepared for Maroochy Shire Council. • WRM Water & Environment (2006b) “Brisbane Valley Flood Damage Minimisation Study Brisbane City Flood Damage Assessment”, WRM Water & Environment Pty Ltd, October 2006, prepared for Brisbane City Council City Design, submitted to the Queensland Floods Commission of Inquiry on 17 May 2011. The Queensland Department of Natural Resources and Mines (DNRM) recommends the use of the ANUFLOOD stage-damage curves for estimating potential flood damages; however there is a consensus that ANUFLOOD underestimates damage values for residential properties. For instance, DIPNR (2004) states: “The Victorian Natural Resources and Environment, Rapid Assessment Method (RAM) for Floodplain Management, May 2000, indicates that ANUFLOOD estimates needed to be increased by 60% to be in the vicinity of Water Studies damages surveys. Even with this adjustment ANUFLOOD estimates are still well below those of Risk Frontiers.” A review of residential stage-damage curves was undertaken as part of the Mackay CBD Drainage Study (AECOM, 2015). This review compares flood damages estimated using the ANUFLOOD stage-damage curves against two of the Australian methods mentioned above and one approach used in the USA, and demonstrates the variation in estimates of flood damages between different approaches. Based on this review, the WRM stage-damage curves and O2 Environmental stage-damage curves based on rebuilding costs were adopted for estimating residential direct damages, to be presented as bounds of potential flood damages.

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9.3.3 Actual and Potential Damages The stage-damage curves used during this study provide estimates of the potential flood damages which would occur during a flood event if no actions were taken to reduce the amount of damage. During actual flood events, residents will usually take measures to reduce the amount of damage incurred, such as moving possessions to higher ground. The reduction in flood damages resulting from such preventative measures is dependent on the warning time available during a flood, the experience of the community in preparing for flooding and whether or not it is possible to move possessions to safety. Residents of West Mackay typically have very little notice prior to a local catchment flood event, as critical durations for the study area are short (in the order of 1 to 2 hours). Therefore the stage- damage curves were not adjusted. An actual to potential damages ratio of 1 has been applied to all the damage curves.

9.4 Building Digitisation and Classification 9.4.1 Building Footprint Digitisation Building footprints were digitized at a visual scale based on aerial imagery. Building footprints are used to determine whether a building is flooded, and to estimate the size of the building required for building classification. The following limitations to building footprints should be noted: • Footprints were digitized based on roof outlines, which may not correspond to the actual building footprint when there is a complex roof shape and given the overhang of eaves. It is unlikely this will significantly impact flood damage estimates, since the variation in area and extent is typically minimal. • Trees obscure some buildings, requiring an assumption of the likely extent and shape of the building. Again, it is unlikely this will significantly impact damages since rarely do trees prevent reasonable assessment of the building shape and extent in this catchment area • Multiple tenancy complexes, e.g. units, shopping centres, strip malls, and warehouses, were digitized as multiple buildings where delineation between individual ownership could be identified from the cadastral boundaries. If a group of buildings could not be digitized separately based on the aerial image, this could skew localized estimates of damages; for instance, a shopping centre digitized as a single building where only the first business was flooded, would produce flood damages for the entire building. • In cases where shared tenancies could not be separated by the cadastral boundaries, flood damages will be estimated based on the mean surveyed habitable floor level or assumed depth above ground elevation around the entire building footprint. This will tend to estimate flood damages only when the majority of the buildings is actually flooded, regardless of whether they were digitized individually or as a group. The area of the building footprint was used for classifying buildings into different size classes. For large commercial buildings, the stage-damage curves give damages in units of $/m2, therefore building areas were used directly in the damage calculations. 9.4.2 Classification To assign classes to buildings, the building footprints were intersected with property information from Terrestrial LiDAR database for residential properties (refer Section 9.5) and the land use planning scheme layer for commercial properties. It is to be noted that commercial property classification includes commercial, industrial and public buildings. 9.4.2.1 Residential Building Classification Residential buildings were further classified based on size, foundation type and storey height to align with the building categories presented in Appendix B. Building classification was based on the floor type classification from the Terrestrial LiDAR database (refer Section 9.5) as well as the area of the digitised building footprints.

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9.4.2.2 Commercial Building Classification Commercial buildings were further classified based on size and value of the building contents to align with the classes presented in Appendix B. Building classification was based on the area of the building footprints, and the property description field of the MRC land use dataset.

9.5 Terrestrial LiDAR Data MRC has recently captured property information through the attainment of Mobile Laser Scanning (MLS) point cloud LiDAR used to develop the Terrestrial LiDAR dataset. The point information contained within the Terrestrial LiDAR dataset (as shown in Figure 20) was joined to MRC’s building database as part of the assessment, this made it easier to attach multiple fields to a singular building footprint for each lot. For the purposes of the tangible flood damages assessment, the building purpose, floor type and habitable floor level information was used to help classify property and assess inundation above floor level.

Figure 20 Visualisation of the Terrestrial LiDAR Database A summary of the attributes tagged to the building footprints is shown in Table 19.

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Table 19 Example Flood Damages Terrestrial LiDAR Attribute Table

LOTPLAN PURPOSE FLOOR_TYPE LEVEL OF_WINDOW OF_WINDOW0 Stumps, Single 18RP712069 Dwelling 11.25 12.20 13.35 Storey

Slab, Double 19RP712069 Dwelling 10.62 0.00 12.51 Storey

17RP712069 UNKNOWN UNKNOWN 0.00 0.00 0.00

Stumps, Single 16RP712069 Dwelling 11.79 12.65 13.87 Storey

Slab, Double 15RP712069 Dwelling 11.22 0.00 13.14 Storey

Stumps, Single 14RP712069 Dwelling 11.92 12.39 0.00 Storey

As shown in Table 19, some properties are missing floor level information or other building attributes, in this case, a desktop assessment using aerial imagery was undertaken to assume the classification and habitable floor level of each residence. This was based upon visible features such as slab height or number of steps into a dwelling. Where a floor level was not visible or easily determined, buildings were assumed to have a minimum habitable floor level of 100 mm above ground level. 9.5.1 Ground Levels The ground level at each building was estimated based on the 1 m LiDAR DEM provided for the project. Ground levels were assigned to the building footprints based on the average elevation of the DEM immediately surrounding the building extents.

9.6 Consumer Price Index Adjustment All stage-damage curves were adjusted to present day dollars based on Consumer Price Index (CPI) ratios. Current CPI values were taken from the most recent statistics available from the Australian Bureau of Statistics (ABS) dated March 2019. The MRC commercial damage curves were adjusted using the CPI for All Groups, as the ratio of structure to contents damages is unknown. The external, contents and structural components of the MRC damage curves were adjusted separately using their relevant CPI. As the MRC curves were developed using the June 2017 CPI’s, the variance over 21 months was not very significant (<10%). Table 20 shows the CPI adjustment ratios for the stage-damage curves.

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Table 20 Council Stage-Damage Curves CPI Adjustment Summary (Mar 2019 $)

Relevant CPI Reference Current CPI Damage Curve Reference Group CPI CPI Ratio

Council Commercial All Groups June, 2017 111.0 114.1 +2.8% Council External Maintenance and June, 2017 repair of motor 107.4 112.1 +4.4% Motor Vehicle vehicle Council External Tools and June, 2017 Equipment for 116.5 106.0 -9.9% Other Damage house and garden Council Contents All Groups June, 2017 111.0 114.1 +2.8% Maintenance and June, 2017 Council Structural 107.8 117.7 +9.2% repair of dwelling Historically, the WRM & O2 Environmental curves have been used for residential tangible flood damages assessments in the Mackay Region, with ANUFLOOD curves utilised for commercial damages. To provide a comparison between the 2018 stage-damage curves and the historical curves, the WRM, O2 Environmental and ANUFLOOD curves have also been adjusted to March 2019 dollars. The commercial ANUFLOOD damage curves were adjusted using the CPI for All Groups, as the allotment of ANUFLOOD damages to structure damages and contents damages is unknown. The external and structural components of the WRM & O2 Environmental damages were adjusted separately using the relevant CPI’s. The external damages adjustment was made using an average of the adjustments for motor vehicles and other external damages. The contents components of the O2 Environmental damages are usually not indexed, as the maximum value of $80,000 for residential contents damages is considered reasonable. Table 21 presents an overview of the historical curve CPI adjustments. Table 21 Historical Stage-Damage Curves CPI Adjustment Summary (March 2019 $)

Reference Current CPI Damage Curve Relevant CPI Group Reference CPI CPI Ratio

ANUFLOOD All Groups DNRM, 2002 74.2 114.1 +53.8% Commercial O2 Residential Maintenance and External repair of motor WRM, 2006 82.8 112.1 +35.4% Motor Vehicle vehicle O2 Residential Tools and Equipment External WRM, 2006 92.0 106.0 +15.2% for house and garden Other Damage O2 Residential O2 Environmental, N/A ------Contents 2012 O2 Residential Maintenance and O2 Environmental, 99.5 117.7 +18.3% Structural repair of dwelling 2012 WRM External Maintenance and repair of motor WRM, 2006 82.8 112.1 +35.4% Motor Vehicle vehicle WRM External Tools and Equipment WRM, 2006 92.0 106.0 +15.2% Other Damage for house and garden WRM Contents All Groups WRM, 2006 83.0 114.1 +37.5% Maintenance and WRM Structural WRM, 2006 88.4 117.7 +33.1% repair of dwelling

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9.7 Damage Categories The tangible damages assessment requires buildings to be categorised in to three building types so that the relevant damages can be applied to the property. These categories are: • Fully Detached Residential; • Multi-Unit Residential; • Commercial. Fully detached residential properties are defined as standalone houses with one residential dwelling per allotment whilst multi-unit dwellings are made up of multiple buildings per allotment whether they are combined or smaller individual residences. Commercial properties are defined as property types. Summary of the residential and commercial property types is discussed in Appendix B. Properties were categorised based on the ‘Building Purpose’ field of Council’s Terrestrial LiDAR database (refer Section 9.5). Multi-unit properties were cross checked using the address fields of the Council cadastral database where the ‘Unit’ code was not equal to 0 (i.e. address formatted as Unit/Number Street Name).

9.8 Classifications and Damage Curves 9.8.1 Residential Residential damages were estimated using the Council 2018 stage-damage curves and have been based on rebuilding costs associated with flooding. Damage calculations were carried out separately for the external, contents and structural damage components and combined to give total damages. This allowed a range of raised building heights to be easily assessed, with external damages increasing with over ground depth, and contents and structural damages increasing with over floor depth. Raised floor levels were identified using MRC’s Terrestrial LiDAR database as per Section 9.5. Refer to Figure 25 through Figure 32 in Appendix B for the residential classifications and damage curves applying to residential buildings. 9.8.2 Commercial Commercial buildings were categorised into the ANUFLOOD commercial classes based on the property description field of the MRC land use dataset. The ANUFLOOD damage value classes for commercial buildings are shown in Appendix B - Figure 24 and Table 30. Commercial damages were estimated using the 2018 stage-damage curves. These curves represent present day adjusted ANUFLOOD commercial stage-damage curves and estimate rebuilding costs associated with flooding inflicted on commercial property. Refer to Figure 33 through Figure 36 in Appendix B for the commercial damage curves applying to commercial buildings.

9.9 Infrastructure Damages Costs associated with damage to infrastructure such as roads, water and wastewater facilities, and utilities have been estimated as 15% of the total direct residential and commercial flood damages. This is consistent with the recommendations of the Office of Environment and Heritage (OEH).

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9.10 Average Annual Damages (AAD) While the methodology above and in Appendix B provides an estimate of potential damages during specific flood events, understanding what damages may be expected on an annual basis is often an easier way to relate risk to residents and businesses. As such, the above damages were converted to Average Annual Damages (AAD) based on the likelihood of the flood event and the total estimated damage during that event. The AAD is determined by taking the estimated damage for each AEP event and multiplying it by the likelihood of the event. The process is repeated and AAD values are summed for the total AAD. For instance, the AAD for a 10% AEP event is based on the estimated $8.02M damages and 10% or 0.10 likelihood, corresponding to an AAD of $802,000. As a result, low-likelihood events such as the PMF have minor influence due to their low probability of occurrence. AAD is a measure of the average tangible flood damages experienced each year, and is calculated as the area under the Probability Damages Curve. Therefore, accurate estimates of AAD require consideration of flood events ranging from the smallest flood that causes damage, up to the PMF. For this study, flood events ranging from the 1 EY AEP (1 year ARI) event up to the PMF have been considered.

10.0 Flood Damages Assessment Results The subsequent sections present a summary of the estimated tangible flood damages (in June 2019 $) for a range of design flood events using the MRC 2018 stage-damage curves.

The results tables have been broken down into external, internal and structural damages (as per the stage-damage curves) as well as infrastructure damages (refer Section 9.9). The tables also show the number of properties impacted by flooding above the habitable floor level. The assessment of flood damages has only included those properties that are within Study Area 1.

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10.1 Present Case – Flood Damages Estimate Table 22 shows the estimated tangible flood damages (in March 2018 $) for a variety of design events, as well as the total AAD for the current catchment conditions.

Table 22 Comparative Tangible Flood Damages Assessment Results - Present Case (, 000’s March 2018 $) # Residential # Floor External Internal Structural Commercial Infrastructure TOTAL Contribution to Event External Level Damages Damages Damages Damages Damages Damages AAD (AEP %) Property Impacts Impacts (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) 1EY - - 0 0 0 0 0 0 1 39% 1 - 6 0 0 0 1 7 2 18% 3 - 11 0 0 0 2 12 1 10% 3 - 12 0 0 0 2 14 2 5% 4 1 16 5 23 0 7 50 2 2% 5 1 20 9 44 0 11 84 1 1% 10 1 42 16 77 0 20 155 1 0.5% 12 2 54 52 226 0 50 381 1 0.2% 22 2 102 61 259 0 63 485 4 PMF 88 16 700 421 1,706 0 424 3,251 0 15

In summary, the Average Annual Damages experienced within the West Mackay model extent in current conditions are approximately $15,000 when calculated using the 2018 stage-damage curves.

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10.2 Mitigation Case - Flood Damages Estimate Table 23 shows the estimated tangible flood damages (in March 2018 $) for a range of design flood events, as well as the total AAD for the modelled flood conditions after construction of the West Mackay Mitigation Options as outlined in Section 8.0.

Table 23 Comparative Tangible Flood Damages Assessment Results - Mitigated Case (, 000’s March 2018 $) # Residential # Floor External Internal Structural Commercial Infrastructure TOTAL Contribution to Event External Level Damages Damages Damages Damages Damages Damages AAD (AEP %) Property Impacts Impacts (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) (,000’s $) 1EY ------39% ------18% ------10% ------5% ------0.1 2% 1 - 6 - - - 1 6 0.1 1% 5 - 16 - - - 2 18 0.1 0.5% 7 - 27 - - - 4 32 0.3 0.2% 14 1 54 1 67 - 18 141 2.4 PMF 80 13 575 52 1,336 - 295 2,258 0.0 3.0

In summary, the Average Annual Damages expected within the West Mackay model extent for the mitigated case will be approximately $3,000 when calculated using the 2018 stage-damage curves.

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10.3 Comparison Table 24 shows the percentage reduction in tangible flood damages anticipated by the incorporation of the preliminary mitigation options. All values are given as a percentage comparison between design case and current conditions (except for floor level impacts which is number of buildings not percentage).

Table 24 Comparative Tangible Flood Damage Assessment Results – Change in Flood Damages (%) (Basecase vs Mitigated Case) Change in Res Change Change in Change in Change in Change in Change in Change in Change in External in Floor External Structural Commercial Event Internal Infrastructure TOTAL Contribution to Property Impacts Impacts Damages Damages Damages (AEP %) Damages (%) Damages (%) Damages (%) AAD (%) (#) (#) (%) (%) (%) 1EY ------100 39% -1 -100 - - - -100 -100 -100 18% -3 -100 - - - -100 -100 -100 10% -3 -100 - - - -100 -100 -100 5% -4 -1 -100 -100 -100 - -100 -100 -95 2% -4 -1 -73 -100 -100 - -92 -92 -90 1% -5 -1 -62 -100 -100 - -88 -88 -91 0.5% -5 -2 -49 -100 -100 - -92 -92 -80 0.2% -8 -1 -47 -98 -74 - -71 -71 -36 PMF -8 -3 -18 -88 -22 - -31 -31 -31 -80

When comparing the flood damages results for the present and design case conditions, a reduction of 80% in Average Annual Damages is experienced. This corresponds to approximately $12,000 in savings on the average tangible flood damages experienced each year, calculated by the area under the Probability Damages Curve.

This reduction has been achieved primarily by reducing the expected flood damages in the events (≥ 5% AEP). Of the 80% reduction in AAD, 61% reduction is experienced in the rarer higher order events (≥ 5% AEP).

A comparison between the total damages expected and number of properties with floor level impacts has been plotted in Figure 21 and Figure 22 for the 1EY through to 1% AEP event and 1% AEP event through to PMF respectively.

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Figure 21 Total Damages and Impacted Properties Plot (1EY to 1% AEP)

Figure 22 Total Damages and Impacted Properties Plot (1% AEP to PMF)

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10.4 Mitigation Case - Other Improvements Improvement in average annual damages costs are vital in determining whether mitigation options will be further investigated; other improvements are difficult to determine a specific dollar value. These include: • Access to roads being maintained during major flood events; • Reduction in flooding at sports facility or parks; • Reduction in clean-up costs due to reducing flooding in public areas; • Increased positive public perception due to flood improvement works. 11.0 Indicative Mitigation Infrastructure Costs

11.1 Structural Mitigation Costs Indicative structural mitigation construction costs (base year 2016) for the proposed structural mitigation option is summarised in Table 25. Table 25 Indicative Structural Mitigation Construction Costs

Mitigation Location Description Indicative Cost Mackenzie St Trunk LOCATION: Douglas, Mackenzie, Holland, Donaldston, Stormwater Chataway, Barton and Mogford Streets. $6,500,000

TOTAL $6,500,000 The indicated project costs were supplied by MRC. 12.0 Cost Benefit of Stormwater Mitigation Assuming a minimum stormwater asset life of 50 years, the preliminary benefit cost ratio for the installation stormwater trunk drainage is 0.093. The primary benefit of the project is reduced over-floor flooding in the vicinity of Mogford Street where residents have previously complained of nuisance flooding. Flood levels at Mogford Street are reduced by as much as 200 mm. There is also a reduction of flooding along Holland Street, with a decrease in flood levels of around 20 mm to 70 mm.

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13.0 Conclusion and Recommendations

13.1 Key Findings The key findings from the TUFLOW hydraulic modelling and associated analysis undertaken for the West Mackay Drainage Study project are summarised below: • Previous studies undertaken within the West Mackay area highlight the drainage issues along Mackenzie, Holland, Mogford and surrounding streets. These studies discussed potential outlet and drain upgrade scenarios; • The area between Crowley Drive and the carparks within the Mackay Base Hospital, particularly the eastern portions has poorly defined pit and pipe infrastructure and may so a flood footprint that may not be normally experienced in the residential lots Crowley Drive or the hospital precinct. Recommended that this information is obtained to be incorporated into future models; • TUFLOW hydraulic modelling undertaken shown that the critical duration for the most constraining area of the West Mackay catchment is the 120 minute storm; • No calibration of the model was undertaken as the model was updated based upon an already calibrated model; • Structural mitigations options were focused on the installation of a stormwater network on parts of Douglas, Holland, Mackenzie, Chataway, Donaldson, Barton and Mogford streets which connects to the existing network in Lagoon St and discharging to the Lagoons area; • The estimated cost for building the new stormwater network was provided by MRC. Total indicative costs are $6,500,000; • A flood damages assessment was undertaken for the 1EY to PMF storms to assess the proposed structural mitigation options to residential and commercial buildings. Average annual damages were reduced by 80%, with over 60% of the reduction occurring for low order events (≥5% AEP); • The project has a cost benefit ratio of 0.093; • Other improvements due to the structure mitigation that are not captured in the damages assessment includes road access being maintained, reduction in clean-up and increased positive public perception.

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14.0 References Australian Emergency Management Institute (2013), Australian emergency management handbook series – Handbook 7 Managing the floodplain: a guide to best practice in flood risk management in Australia. Australian Rainfall and Runoff (2013). Project 11 – Blockage of Hydraulic Structures. Available at: http://arr.ga.gov.au/ , accessed April 2018. Australian Rainfall and Runoff (2012). Project 15 – 2D Modelling in Urban and Rural Floodplains – Stage 1 & 2 Report. Available at: http://arr.ga.gov.au/ , accessed April 2018. BMT WBM (2016), TUFLOW User Manual – Build 2016-03-AE. Department of Energy and Water Supply (DEWS) (2013), Queensland Urban Drainage Manual (QUDM) – Third Edition. Department of the Environment and Energy, CoastAdapt and the National Climate Change Adaptation Research Facility (NCCARF) (2017), What are the RCPs? Available at: https://coastadapt.com.au/sites/default/files/infographics/15-117-NCCARFINFOGRAPHICS-01- UPLOADED-WEB%2827Feb%29.pdf , accessed February 2018. Department of Transport and Main Roads (TMR) (2015), Road Drainage Manual. Geoscience Australia (2016), Australian Rainfall and Runoff (AR&R) – A Guide to Flood Estimation Institute of Public Works Engineering Australasia (IPWEA) (Queensland Division), Queensland Urban Drainage Manual (QUDM) – Fourth Edition. Institution of Engineers Australia (1998), Australian Rainfall and Runoff (AR&R) – A Guide to Flood Estimation Volumes 1 & 2. Office of Climate Change – Queensland Department of Environment and Resource Management, Queensland Department of Infrastructure and Planning and Local Government Association of Queensland (2010), Increasing Queensland’s resilience to inland flooding in a changing climate: Final report on the Inland Flooding Study.

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Appendix A

Hydraulic Model Development

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Appendix A Hydraulic Model Development Model Setup Parameters The time step for the 1D domain was set to 0.5 seconds. TUFLOW’s HPC solver has a variable time step for 2D overland flow and the specified minimum time step was 0.8 seconds. These time steps are within the feasible time step range given the grid cell size. The wetting and drying depth represents the depth of water on a cell which is the criteria for whether the cell is “wet” or “dry”. Direct rainfall modelling applies rainfall to each cell in small increments, so the wetting and drying values must also be very small or the calculation will not take place. The wetting and drying depth has been set to the default of 0.0002 m for the centre of a cell and 0.001 m for the side of a cell. One Dimensional Model Development Modelling parameters associated with the 1D network are consistent with the recommended loss values in the TUFLOW reference manual. Manning’s roughness values applied to the cross-drainage infrastructure is consistent with aged concrete and applies the same assumptions for developed case models. As outlined in Section 3.7.1, Council provided a database of existing stormwater drainage networks including culverts within the study area. These networks have been incorporated into the model as 1d elements, which are dynamically linked to the 2D domain via pit structures. All culverts were represented as dynamically linked 1D elements with major sets of closely situated and larger culverts being digitized using multi-cell links (CN-SX lines). Culvert roughness was set as 0.013 for RCPs and RCBCs. Site specific roughness values and blockage were not applied into the model as no calibration or validation data available to check validity of those claims. The default culvert loss values applied to models are based on the TUFLOW user’s manual (WBM BMT) on satisfying conditions of cross drainage structures. Pit inlet types were specified from the pit database provided by Council. Varying depth vs flow inlet curves were provided which determine the amount of water able to enter a pit based on the depth of the flood surface over the pit. Pit inlet levels were based upon the LiDAR elevation data and lowered by 0.1m in order to help capture overland flow. Model Topography Base model topography was derived from LiDAR data supplied by Council as a 1 m resolution Digital Elevation Model (DEM). A 4 m grid was adopted for the hydraulic model which is consistent with previous studies within the Mackay area. This grid size provides sufficient representation of flow paths through streets and around buildings while keeping the model within reasonable simulation times. Hydraulic Roughness and Losses The specified hydraulic roughness reflects the different types of development and ground cover that exists within the hydraulic model extent. The roughness categories adopted for this study were developed based on roughness maps developed in previous studies, aerial imagery, building footprints, site visits and land use zoning information. Variable Manning’s ‘n’ values based on depth can be utilised within TUFLOW. Manning’s ‘n’ 1 is applied for all flow depths up to depth 1, between depths 1 and 2 the Manning’s ‘n’ is interpolated between Manning’s ‘n’ 1 and 2 and for all depths greater than depth 2 Manning’s ‘n’ 2 is applied. In the instance of road reserve and open water a single roughness has been applied. Specific roughness values for each category as applied in the model are outlined in Table 26.

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Table 26 Adopted Roughness Values

Manning’s ‘n’ Material Description Depth 1 Manning’s Depth 2 Manning’s (m) ‘n’ 1 (m) ‘n’ 2 Residential 0.1 0.070 0.3 0.090 Open Space and Recreational Areas 0.1 0.050 0.3 0.032 Road Reserve 0.025 Rural Residential 0.1 0.070 0.3 0.040 Commercial / Manufacturing 0.1 0.060 0.3 0.030 Open Water 0.027 Cane Rail 0.1 0.072 0.3 0.059 Sugar Cane 0.1 0.130 0.3 0.050 Channel 0.1 0.035 0.3 0.030 Buildings 0.1 0.018 0.3 0.500 Dense Vegetation 0.1 0.090 0.3 0.060 Long Grass Channel 0.1 0.045 0.7 0.030 Medium Grass Channel 0.1 0.075 0.3 0.050 Light Vegetation 0.1 0.060 0.3 0.045 Rainfall losses allow TUFLOW to model situations in which water is prevented from reaching the ground or is infiltrated into the soil system before surface ponding and/or runoff occurs. When using a direct rainfall approach initial losses and continuing losses are specified as a soils. The soils file shares identical definitions to roughness. Any losses applied are removed from the rainfall depth prior to being applied as a boundary on the 2D cells. Once the initial losses have been satisfied the soil is considered saturated and any additional rainfall will become surface runoff. Many other Council local catchment studies utilise initial / continuing loss models. For consistency, similar losses have been adopted in this study in absence of model calibration and validation. The initial losses and continuing losses applied to this model are indicated below in Table 27. Table 27 Adopted Initial and Continuing Loss Values

Material Description Initial Loss (mm) Continuing Loss (mm/hr) Residential 15 2 Open Space and Recreational 15 2 Areas Road Reserve 0 0 Rural Residential 15 2 Commercial / Manufacturing 5 1 Open Water 0 0 Cane Rail 10 1 Sugar Cane 20 2 Channel 10 2 Buildings 0 0 Dense Vegetation 15 2

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Material Description Initial Loss (mm) Continuing Loss (mm/hr) Long Grass Channel 15 1 Medium Grass Channel 15 1 Light Vegetation 15 1 Initial Conditions Initial water levels were applied to the 2D domain. The Mean High Water Springs (MHWS) tidal elevation of 2.46 m AHD was specified for the Pioneer River and Lagoon area for the baseline scenario and mitigation events. This was increased by 0.8 m for climate change sensitivity runs and the Highest Astronomical Tide (HAT) level of 3.64 m AHD was adopted for the PMF. Due to the relatively high elevation across the study area this initial water level did not impact the points of interest. Boundary Conditions A range of different boundary conditions have been applied within the West Mackay Drainage Study hydraulic model. The types of boundaries are as follows: • Direct rainfall over 2D model terrain. • A static Height varying time (HT) boundary around the Pioneer and River and Lagoon area. • Height-varying discharge (HQ) outflow boundaries based on surface slope for flows leaving the model downstream. Direct rainfall has been applied to the 2D domain covering the West Mackay study area. HQ type boundaries allow flood waters to discharge from the model relative to the water surface elevation. HT type boundaries allow flood waters to discharge from the model relative to an assigned water surface elevation. A constant level of 2.46 m AHD was applied at the Pioneer River and the Lagoon outlets for all design runs with the exception of climate change sensitivity and the PMF as explained above under “Initial Conditions.” Critical Duration The critical duration for the West Mackay study area was determined from the hydraulic model as a rain on grid methodology replaces the need to construct a separate hydrological model. The determination of the critical duration was based upon the 1% AEP and this duration was then applied to more frequent events. The critical duration was determined separately for each rare design event individually. The determination of the critical duration for the 1% AEP event was performed in two stages. Firstly, a suite of events ranging from the 60 minute to the 1440 minute storm duration were run using the 1987 temporal pattern in combination with 2016 rainfall IFD values. This initial step allowed an initial estimate of the critical duration in order to reduce the number of durations that would be examined using the 2019 ARR methodology. The 2019 methodology uses ten temporal patterns for every duration. This means a significant number of hydraulic model simulations would need to be run if every duration were tested for all temporal patterns. The results of the hydraulic modelling based upon the 1987 temporal pattern showed a range of critical durations throughout the catchment area. As it is desirable for model simulation times to reduce the number of durations to a single duration, therefore one representative duration was selected from among the critical durations. Based on an analysis of flood depths in different regions of the West Mackay study area the 120 minute storm was considered to be most representative of peak flood depths throughout the catchment. Figure 23 shows eight locations at which flood depths were examined for the 60 minute, 120 minute, 180 minute and 270 minute storms. The 120 minute storm matched closely to the depth values of both the 60 minute and 270 minute storms in the regions in which these were critical. The 120 minute storm was within 30 mm in those locations in which the 270 minute storm was critical and within at least 50 mm in those locations in which the 60 minute storm

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was critical. Table 28 summarises these results. Furthermore, the 120 minute storm is itself the critical storm in a significant amount of the key Study Area 1. Table 28 Differences in Water Level at Selected Locations for 1% AEP Storm Events for 1987 pattern

Depth of Storm Event (m) Location 60 min (m) 120 min (m) 180 min (m) 270 min (m) 1 0.382 0.386 0.383 0.385

2 0.407 0.418 0.418 0.419

3 0.397 0.419 0.421 0.422

4 0.341 0.362 0.357 0.361

5 0.168 0.178 0.171 0.176

6 0.500 0.508 0.504 0.508

7 0.595 0.628 0.635 0.636

8 0.116 0.111 0.108 0.107

A temporal pattern analysis was also performed using the 2016 temporal patterns. This analysis used the 60, 120 and 180 minute storm durations. These durations were run for all ten temporal patterns for the Wet Tropics region. The median values for the model extent were extracted from the ten temporal patterns for each duration. These median values from each duration where then combined into a grid that represented PWSE. As can be seen in Figure 8 a significant extent of the model area showed a 60 minute critical duration. However, analysis of the PWSE showed the 120 minute storm still represented a very close match to maximum water surface levels across the whole catchment. Water depth differences between the 60 min and 120 min storms were less than 25 mm. The values at the point locations are summarised in Table 28. The two hour storm event was selected as the critical duration for all more frequent events which are modelled upon the 1987 temporal patterns. Table 29 Differences in Water Level at Selected Locations for 1% AEP Storm Events for 2016 patterns

Depth of Storm Event (m) Location 60 min (m) 120 min (m) 180 min (m) 1 0.355 0.333 0.332

2 0.398 0.405 0.404

3 0.385 0.406 0.407

4 0.328 0.319 0.311

5 0.140 0.120 0.115

6 0.479 0.463 0.459

7 0.585 0.632 0.642

8 0.109 0.094 0.087

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Figure 23 Locations of Points Comparing Depths for Critical Storms

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Appendix B

Damage Categories and Curves

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Appendix B Damage Categories and Curves Residential Property Sub-Categories Properties identified as residential (fully detached or multi-unit) were then categorised based on the ‘Floor Type’ field of Council’s Terrestrial LiDAR database (refer Section 9.5). The 6 residential property sub-categories are as follows: • Fully Detached Residential: - Fully detached, lowset, single storey, slab-on-ground (FDSS-SOG) - Fully detached, lowset, single storey, stumps (FDSS-Stumps) - Fully detached, highset (FDHS) - Fully detached, double storey (FDDS). • Multi-Unit Residential: - Semi/non-detached (multi-unit) single storey (MUSS) - Semi/non-detached (multi-unit) double storey (MUDS). It is to be noted that fully detached highset (built-in) houses were classed as FDDS, fully detached houses on stumps (not built-in) with less than 2.0m difference between floor level and ground level were classed as FDSS-Stumps and when clearance reached 2.0m or greater they were classed as FDHS. Using the damage categories applied to each property, buildings on slabs (FDSS-SOG, FDDS, MUSS, MUDS) were assumed to have a minimum habitable floor level of 100mm above ground level. Low set buildings (FDSS-Stumps) were assumed to have a minimum habitable floor level of 600mm above ground level and high set buildings (FDHS) were assumed to have a minimum habitable floor level of 1,800mm above ground level. Buildings with floor levels below ground level were increased based on their category specified above. Buildings lacking data regarding what type of floor they have were assumed to be on slabs.

Commercial Categories Commercial buildings were categorised into the ANUFLOOD commercial classes based on the property description field of the Council land use dataset. The ANUFLOOD damage value classes for commercial buildings are shown in Figure 24.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-2

Figure 24 ANUFLOOD Commercial Damage Value Classes (DNRM, 2002) Commercial buildings were assigned an ANUFLOOD damage class value based on the property description field of the council land use dataset. Where the property description code did not correspond directly to an ANUFLOOD damage value class, a reasonable value class was assigned. Table 30 shows the value class assigned to each property description code in the Council land use dataset. Table 30 Assignment of Commercial Damage Class Curves Based on Council Land Use Dataset

Council Land Use Class Council Land Use Class Council Land Use Class Animals Special 3 Horses 1 Service Station 2 Builders Hospitals/Nursing Yards/Contractors 3 2 Shop Single 3 Homes Yard Car Park 2 Hotel/Tavern 2 Shops 2 to 6 3 Car Yards etc. 2 Iceworks 2 Shops Main Retail 3 Irrigation Small Caravan Parks 2 2 Shops over 6 3 Corps Cattle Shops Secondary 2 Library 3 3 Breeding/Fattening Retail Child Care Centre 1 Licenced Clubs 2 Showgrounds etc. 2 Churches/Halls 1 Light Industry 3 Sports Clubs 2 Clubs Non-Business 2 Motel 2 Theatre/Cinema 3 Council Owned 2 Nurseries 2 Transformers 3 Defence Forces 4 Offices 2 Transport Terminal 3

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-3

Council Land Use Class Council Land Use Class Council Land Use Class Drive Shopping 3 Oil Depot 3 Tropical Fruits 1 Centre Fire/Ambulance 3 Parks & Gardens 1 Uni/Schools etc. 2 Funeral Parlours 1 Reservoirs etc. 3 Vineyards 2 General Industry 3 Restaurant 2 Warehouses etc. 3 Retail Warehouse & Guesthouse 2 2 Service Station 2 Showroom School 2 Shop Single 3 Building Footprint Size Furthermore to the category, a building footprint size is also required to attribute each property to the correct stage-damage curve for their size. As the building footprints have been digitised as part of the damages assessment (refer Section 9.4.1) using GIS software the footprint size can be automatically calculated. From this size, the building can then be classified as a small, medium or large type property based on the following criteria: • Fully Detached and Multi-Unit Residential Properties: - Small (< 140m2) - Medium (140 to 210m2) - Large (> 210m2). • Commercial Properties: - Small (< 186m2) - Medium (186 to 650m2) - Large (> 650m2).

Fully Detached Residential Damages Fully detached residential damages were estimated using the Council 2018 stage-damage curves and have been based on rebuilding costs associated with flooding. Damage calculations were carried out separately for the external, contents and structural damage components and combined to give total damages. This allowed a range of raised building heights to be easily assessed, with external damages increasing with over ground depth, and contents and structural damages increasing with over floor depth. Raised floor levels were identified using Council’s Terrestrial LiDAR database as per Section 9.5. All damage values have been adjusted to December 2017 Dollars, which corresponds to the most recent Consumer Price Index (CPI) values available. Details of the adjustment are provided in Section 9.6. No adjustment of Stage-Damage curves to represent actual / potential flood damages was undertaken, as described in Section 9.3.3. Figure 25 shows the decision processes made as part of the fully detached residential building classification prior to applying the relevant stage-damage curve. The 12 classifications as shown in the flow chart have individual stage-damage curves that have been graphed in Figure 26 through Figure 29. Individual curves are given for external, contents and structural damages, however these graphs present stage damage curves representing total flood damages (sum of external, contents and structural damages). The historical WRM and O2Environmental curves (CPI adjusted to December 2017 dollars) have also been graphed for comparison.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-4

Figure 25 Fully Detached Residential Building Classification Flowchart

Figure 26 Combined Stage-Damage Curves: FDSS-SOG

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-5

Figure 27 Combined Stage-Damage Curves: FDSS-Stumps

Figure 28 Combined Stage-Damage Curves: FDDS

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Figure 29 Combined Stage-Damage Curves: FDHS Indirect Fully Detached Residential Damages Indirect fully detached residential damages were assumed to be 15% of the total direct residential damages (DNRM, 2002).

Multi-Unit Residential Damages Multi-unit residential damages were estimated using the Council 2018 stage-damage curves and have been based on rebuilding costs associated with flooding. Damage calculations were carried out separately for the external, contents and structural damage components and combined to give total damages. This allowed a range of raised building heights to be easily assessed, with external damages increasing with over ground depth, and contents and structural damages increasing with over floor depth. Raised floor levels were identified using Council’s Terrestrial LiDAR database as per Section 9.5. All damage values have been adjusted to December 2017 Dollars, which corresponds to the most recent Consumer Price Index (CPI) values available. Details of the adjustment are provided in Section 9.6. No adjustment of Stage-Damage curves to represent actual / potential flood damages was undertaken, as described in Section 9.3.3. Figure 30 shows the decision processes made as part of the multi-unit residential building classification prior to applying the relevant stage-damage curve. The 6 classifications as shown in the flow chart have individual stage-damage curves that have been graphed in Figure 31 and Figure 32. Individual curves are given for external, contents and structural damages, however these graphs present stage damage curves representing total flood damages (sum of external, contents and structural damages). The historical WRM and O2Environmental curves (CPI adjusted to December 2017 dollars) have also been graphed for comparison.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-7

Figure 30 Multi-Unit Residential Building Classification Flowchart

Figure 31 Combined Stage-Damage Curves: MUSS

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-8

Figure 32 Combined Stage-Damage Curves: MUDS Indirect Multi-Unit Residential Damages Indirect multi-unit residential damages were assumed to be 15% of the total direct residential damages (DNRM, 2002).

Commercial Damages Commercial damages were estimated using the Council 2018 stage-damage curves. These curves represent present day adjusted ANUFLOOD commercial stage-damage curves and estimate rebuilding costs associated with flooding inflicted on commercial property. Commercial buildings were assigned a value class based on their use. Details on commercial building classification are presented in Table 30. It should be noted that large-classed building damages were estimated using area directly (i.e. the large-class building damage curves are in units of $/m2 vs. $). Raised floor levels were applied using the surveyed floor level from the Council’s Terrestrial LiDAR dataset. Estimated damages were assumed to remain constant after a depth over floor of 4m, corresponding to the maximum damage value provided in the ANUFLOOD literature. All damage values have been adjusted to March 2019 Dollars, which corresponds to the most recent Consumer Price Index (CPI) values available. Details of the adjustment are provided in Section 9.6. No adjustment of Stage-Damage curves to represent actual / potential flood damages was undertaken, as described in Section 9.3.3. Figure 33 shows the decision processes made as part of the multi-unit residential building classification prior to applying the relevant stage-damage curve. The 15 classifications as shown in the flow chart have individual stage-damage curves that have been graphed in Figure 34 through Figure 36. The historical ANUFLOOD curves (CPI adjusted to March 2019 dollars) have also been graphed for comparison.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-9

Figure 33 Commercial Building Classification Flowchart

Figure 34 Total Stage-Damage Curve: Small Commercial

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report B-10

Figure 35 Total Stage-Damage Curve: Medium Commercial

Figure 36 Total Stage-Damage Curve: Large Commercial Indirect Commercial Damages Indirect damages for commercial buildings were assumed to be 55% of the direct damages. This number is significantly higher than the indirect damage value for residential buildings due to the assumed loss of business revenue, according to the ANUFLOOD literature. It should be noted that this applies to all buildings classified as commercial, which includes community assets such as park facilities, schools, etc. which may not actually recognize business–related revenue.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report

Appendix C

Property Impacts Assessment

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-1

Appendix C Property Impacts Assessment A property by property impacts assessment was undertaken for allotments within the West Mackay model boundary. This assessment was undertaken to ensure that that there is no worsening to present flood conditions for properties within the West Mackay Study area. The assessment was undertaken for all properties within the West Mackay model boundary in Figure 3. Property information such as floor levels and dwelling type was provided by MRC, which was obtaining using Mobile Laser Scanning. The following limitations should be noted in regards to the assessment: • Design flood events were assessed using a single critical duration (120 min storm), based on an analysis of multiple storm durations for the 1% AEP event (refer Section 5.3). • The hydraulic models have not been calibrated to any historical events as the model was based upon and already calibrated model. • Aerial survey data (in the form of LiDAR) used to develop the topography for the hydraulic model has a vertical accuracy of ±0.15 m on clear, hard surfaces and a horizontal accuracy of ±0.45 m. • Results presented are based on peak values of water surface elevation, flow, depth and velocity. Therefore, using flood levels as an example, the peak level does not occur everywhere at the same time and, therefore, the values presented are based on taking the maximum value which occurred at each computational point in the model during the entire flood. Hence, a presentation of peak levels does not represent an instantaneous point in time, but rather an envelope of the maximum values that occurred at each computational point over the duration of the flood event. • The velocity values reported are from the depth-averaged velocity value reported by TUFLOW and velocities may be higher at a certain depths. • The slope of allotments may report higher PWSEs higher than that of the floor level, although the floor level may not be inundated. This is due to the steep terrain of some lots and shallow surface flooding towards the rear (higher end) of the allotments. • Floor levels under ground level were increased based on building classifications as discussed in Appendix B.

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-1

Property Floor Levels and Classification Properties with supplied Terrestrial LiDAR HFL lower than that of the average ground LiDAR levels surrounding the building footprint is shown in red text, surveyed floor levels shown as green text and floor levels assumed based on building levels (edge levels, windows levels and building heights) is shown as blue text.

Properties of Study Area 1 is summarised in Table 31.

Table 31 Property Floor Levels and Classifications Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 1/74 Holland Street WEST 9.98 10.02 FDSS-SOG-M MACKAY QLD 4740 10.12 1/51 Mackenzie Street WEST 0.00 10.42 10.17 FDSS-SOG-M MACKAY QLD 4740 10.42 64 Lagoon Street WEST 0.00 11.52 11.28 FDSS-SOG-M MACKAY QLD 4740 11.52 50 Jackson Street WEST 11.87 11.89 FDSS-SOG-L MACKAY QLD 4740 12.00 30 Jackson Street WEST FDSS- 11.62 10.76 MACKAY QLD 4740 Stumps-S 11.62 23 Jackson Street WEST FDSS- 0.00 11.31 10.53 MACKAY QLD 4740 Stumps-S 11.31 32 Jackson Street WEST FDSS- 11.58 10.88 MACKAY QLD 4740 Stumps-M 11.58 34 Jackson Street WEST FDSS- 11.54 10.96 MACKAY QLD 4740 Stumps-M 11.54 36 Jackson Street WEST FDSS- 11.34 10.91 MACKAY QLD 4740 Stumps-M 11.34 27 Jackson Street WEST 0.00 10.87 10.63 FDSS-SOG-M MACKAY QLD 4740 10.87 78 Mogford Street WEST 10.62 10.51 FDSS-SOG-L MACKAY QLD 4740 10.62 79 Holland Street WEST 10.42 10.34 FDSS-SOG-L MACKAY QLD 4740 10.42 1/70 Holland Street WEST 10.02 9.82 FDSS-SOG-M MACKAY QLD 4740 10.05 1/4 Douglas Street WEST 10.88 10.68 FDSS-SOG-M MACKAY QLD 4740 10.88 84 Holland Street WEST FDSS- 12.33 10.27 MACKAY QLD 4740 Stumps-S 12.33 30 Mackenzie Street WEST 9.85 10.14 FDHS-S MACKAY QLD 4740 11.94 80 Lagoon Street WEST FDSS- 12.10 11.45 MACKAY QLD 4740 Stumps-M 12.10 16 Jackson Street WEST FDSS- 0.00 11.73 10.88 MACKAY QLD 4740 Stumps-M 11.73 21 Barton Street WEST 11.47 11.41 FDDS-M MACKAY QLD 4740 11.47

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-2

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 46 Lagoon Street WEST 11.63 11.58 FDSS-SOG-L MACKAY QLD 4740 11.63 26 Douglas Street WEST FDSS- 12.45 10.41 MACKAY QLD 4740 Stumps-M 12.45 24 Douglas Street WEST FDSS- 12.74 10.58 MACKAY QLD 4740 Stumps-L 12.74 22 Douglas Street WEST FDSS- 12.40 10.41 MACKAY QLD 4740 Stumps-M 12.40 20 Douglas Street WEST 10.82 10.58 FDDS-M MACKAY QLD 4740 10.82 18 Douglas Street WEST FDSS- 10.99 10.59 MACKAY QLD 4740 Stumps-L 10.99 17 Jackson Street WEST 0.00 11.15 10.91 FDSS-SOG-M MACKAY QLD 4740 11.15 19 Jackson Street WEST FDSS- 12.81 10.57 MACKAY QLD 4740 Stumps-S 12.81 21 Jackson Street WEST 11.26 10.74 FDSS-SOG-S MACKAY QLD 4740 11.26 132 Donaldson Street WEST FDSS- 11.40 10.56 MACKAY QLD 4740 Stumps-M 11.40 78 Lagoon Street WEST FDSS- 11.96 11.36 MACKAY QLD 4740 Stumps-M 11.96 44 Lagoon Street WEST 11.74 11.52 FDDS-M MACKAY QLD 4740 11.74 32A Mackenzie Street WEST FDSS- 10.95 10.13 MACKAY QLD 4740 Stumps-S 10.95 18 Jackson Street WEST FDSS- 11.17 10.71 MACKAY QLD 4740 Stumps-M 11.17 20 Jackson Street WEST FDSS- 0.00 11.37 10.77 MACKAY QLD 4740 Stumps-L 11.37 22 Jackson Street WEST FDSS- 11.41 10.82 MACKAY QLD 4740 Stumps-M 11.41 34 Mackenzie Street WEST FDSS- 10.60 10.15 MACKAY QLD 4740 Stumps-M 10.60 76 Lagoon Street WEST FDSS- 11.94 11.37 MACKAY QLD 4740 Stumps-M 11.94 42 Lagoon Street WEST 11.66 11.48 FDSS-SOG-L MACKAY QLD 4740 11.66 36 Mackenzie Street WEST FDSS- 10.71 10.12 MACKAY QLD 4740 Stumps-S 10.71 74 Lagoon Street WEST FDSS- 12.08 11.36 MACKAY QLD 4740 Stumps-L 12.08 40 Lagoon Street WEST 11.44 11.54 FDSS-SOG-L MACKAY QLD 4740 11.64 38 Mackenzie Street WEST FDSS- 10.97 10.09 MACKAY QLD 4740 Stumps-M 10.97

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-3

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 66 Mackenzie Street WEST FDSS- 11.92 11.49 MACKAY QLD 4740 Stumps-S 11.92 38 Lagoon Street WEST 14.10 11.49 FDDS-M MACKAY QLD 4740 11.58 32 Mackenzie Street WEST 0.00 10.72 10.48 FDSS-SOG-M MACKAY QLD 4740 10.72 40 Mackenzie Street WEST 0.00 10.40 10.15 FDSS-SOG-M MACKAY QLD 4740 10.40 64 Mackenzie Street WEST 11.22 11.26 FDDS-S MACKAY QLD 4740 11.36 36 Lagoon Street WEST 11.78 11.58 FDSS-SOG-L MACKAY QLD 4740 11.78 111 Donaldson Street WEST 10.90 10.11 FDSS-SOG-L MACKAY QLD 4740 10.90 76 Holland Street WEST FDSS- 10.65 10.27 MACKAY QLD 4740 Stumps-M 10.65 42 Mackenzie Street WEST FDSS- 0.00 10.91 10.07 MACKAY QLD 4740 Stumps-L 10.91 62 Mackenzie Street WEST FDSS- 11.79 11.04 MACKAY QLD 4740 Stumps-M 11.79 34 Lagoon Street WEST 14.06 11.66 FDDS-L MACKAY QLD 4740 11.76 44 Mackenzie Street WEST FDSS- 10.92 10.27 MACKAY QLD 4740 Stumps-L 10.92 60 Mackenzie Street WEST FDSS- 0.00 11.90 11.06 MACKAY QLD 4740 Stumps-L 11.90 32 Lagoon Street WEST 11.71 11.71 FDSS-SOG-M MACKAY QLD 4740 11.71 403 Bridge Road WEST 0.00 10.21 9.80 FDSS-SOG-M MACKAY QLD 4740 10.21 403 Bridge Road WEST 0.00 10.17 9.76 COM2-L MACKAY QLD 4740 10.17 403 Bridge Road WEST 0.00 10.28 9.87 COM2-L MACKAY QLD 4740 10.28 403 Bridge Road WEST 0.00 10.40 9.99 COM2-M MACKAY QLD 4740 10.40 403 Bridge Road WEST 0.00 10.46 10.06 COM2-M MACKAY QLD 4740 10.46 403 Bridge Road WEST 0.00 10.46 10.06 COM2-M MACKAY QLD 4740 10.46 403 Bridge Road WEST 0.00 10.42 10.02 COM2-M MACKAY QLD 4740 10.42 403 Bridge Road WEST 0.00 10.29 9.88 COM2-M MACKAY QLD 4740 10.29 403 Bridge Road WEST 0.00 12.84 9.72 COM2-M MACKAY QLD 4740 9.82

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-4

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 403 Bridge Road WEST 0.00 13.09 9.97 COM2-L MACKAY QLD 4740 10.07 15 Douglas Street WEST FDSS- 0.00 11.13 10.29 MACKAY QLD 4740 Stumps-S 11.13 58 Mackenzie Street WEST FDSS- 11.25 10.82 MACKAY QLD 4740 Stumps-M 11.25 29 Barton Street WEST 0.00 11.45 11.20 FDSS-SOG-L MACKAY QLD 4740 11.45 13 Douglas Street WEST FDSS- 10.95 10.35 MACKAY QLD 4740 Stumps-M 10.95 56 Mackenzie Street WEST 10.62 10.59 FDDS-M MACKAY QLD 4740 10.62 31 Barton Street WEST 11.13 11.22 FDSS-SOG-L MACKAY QLD 4740 11.32 1/77 Holland Street WEST 10.26 10.16 MUSS-L MACKAY QLD 4740 10.26 2/51 Mackenzie Street WEST 0.00 10.41 10.16 MUSS-L MACKAY QLD 4740 10.41 46 Jackson Street WEST 11.98 11.22 FDSS-SOG-M MACKAY QLD 4740 11.98 48 Jackson Street WEST FDSS- 12.03 11.37 MACKAY QLD 4740 Stumps-M 12.03 27 Jackson Street WEST FDSS- 10.94 10.67 MACKAY QLD 4740 Stumps-M 10.94 28 Jackson Street WEST FDSS- 11.71 10.81 MACKAY QLD 4740 Stumps-M 11.71 134 Donaldson Street WEST 11.10 10.92 FDDS-S MACKAY QLD 4740 11.10 76 Mogford Street WEST 10.60 10.53 FDSS-SOG-L MACKAY QLD 4740 10.60 81 Holland Street WEST 10.47 10.41 FDDS-M MACKAY QLD 4740 10.47 2/70 Holland Street WEST 0.00 10.22 9.97 FDSS-SOG-M MACKAY QLD 4740 10.22 4 Douglas Street WEST 10.91 10.77 FDSS-SOG-M MACKAY QLD 4740 10.91 1A Chataway Street WEST 10.91 10.71 FDSS-SOG-L MACKAY QLD 4740 10.91 11 Douglas Street WEST FDSS- 10.97 10.23 MACKAY QLD 4740 Stumps-M 10.97 21 Chataway Street WEST 10.92 10.89 FDHS-M MACKAY QLD 4740 10.92 33 Barton Street WEST 11.15 11.20 FDDS-L MACKAY QLD 4740 11.30 9 Douglas Street WEST FDSS- 11.12 10.23 MACKAY QLD 4740 Stumps-L 11.12

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-5

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 23 Chataway Street WEST FDSS- 11.53 10.81 MACKAY QLD 4740 Stumps-S 11.53 35 Barton Street WEST 11.17 11.08 FDDS-M MACKAY QLD 4740 11.17 82 Holland Street WEST FDSS- 10.88 10.23 MACKAY QLD 4740 Stumps-S 10.88 7 Douglas Street WEST 0.00 10.59 10.35 FDSS-SOG-S MACKAY QLD 4740 10.59 25 Chataway Street WEST FDSS- 11.35 11.21 MACKAY QLD 4740 Stumps-L 11.35 37 Barton Street WEST 11.22 11.21 FDSS-SOG-L MACKAY QLD 4740 11.22 27 Chataway Street WEST FDSS- 11.39 10.88 MACKAY QLD 4740 Stumps-L 11.39 39 Barton Street WEST 11.31 11.17 FDSS-SOG-L MACKAY QLD 4740 11.31 5 Douglas Street WEST FDSS- 11.36 10.42 MACKAY QLD 4740 Stumps-M 11.36 3 Douglas Street WEST FDSS- 11.15 10.59 MACKAY QLD 4740 Stumps-M 11.15 31 Chataway Street WEST FDSS- 11.72 11.05 MACKAY QLD 4740 Stumps-M 11.72 41 Barton Street WEST 11.22 11.08 FDSS-SOG-M MACKAY QLD 4740 11.22 5A Douglas Street WEST 0.00 10.78 10.53 FDSS-SOG-M MACKAY QLD 4740 10.78 1 Douglas Street WEST FDSS- 11.13 10.42 MACKAY QLD 4740 Stumps-M 11.13 31 Chataway Street WEST FDSS- 11.77 11.13 MACKAY QLD 4740 Stumps-S 11.77 36 Barton Street WEST 10.97 10.76 FDSS-SOG-L MACKAY QLD 4740 10.97 2 Douglas Street WEST FDSS- 11.15 10.43 MACKAY QLD 4740 Stumps-M 11.15 33 Chataway Street WEST FDSS- 11.76 11.57 MACKAY QLD 4740 Stumps-M 11.76 100 Mogford Street WEST 10.63 10.96 FDSS-SOG-M MACKAY QLD 4740 11.09 68 Lagoon Street WEST 11.42 11.12 FDSS-SOG-L MACKAY QLD 4740 11.42 98 Mogford Street WEST 10.85 10.35 FDSS-SOG-L MACKAY QLD 4740 10.85 6 Douglas Street WEST FDSS- 11.15 10.42 MACKAY QLD 4740 Stumps-M 11.15 66 Lagoon Street WEST FDSS- 12.09 11.16 MACKAY QLD 4740 Stumps-S 12.09

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-6

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 96 Mogford Street WEST 10.32 10.38 FDDS-M MACKAY QLD 4740 10.48 8 Douglas Street WEST 10.78 10.60 FDDS-L MACKAY QLD 4740 10.78 94 Mogford Street WEST 10.50 10.46 FDSS-SOG-L MACKAY QLD 4740 10.51 2/74 Holland Street WEST 0.00 10.34 10.09 MUSS-L MACKAY QLD 4740 10.25 3/64 Lagoon Street WEST 0.00 11.51 11.26 FDSS-SOG-L MACKAY QLD 4740 11.51 44 Jackson Street WEST FDSS- 11.92 11.11 MACKAY QLD 4740 Stumps-S 11.92 2 Jackson Street WEST 0.00 10.77 10.52 FDSS-SOG-M MACKAY QLD 4740 10.77 77 Mogford Street WEST 10.91 10.67 FDSS-SOG-L MACKAY QLD 4740 10.91 83 Holland Street WEST 10.46 10.50 FDSS-SOG-M MACKAY QLD 4740 10.60 10 Douglas Street WEST FDSS- 11.13 10.50 MACKAY QLD 4740 Stumps-S 11.13 56 Lagoon Street WEST FDSS- 11.78 11.28 MACKAY QLD 4740 Stumps-M 11.78 92 Mogford Street WEST 0.00 10.79 10.37 FDDS-L MACKAY QLD 4740 10.79 12 Douglas Street WEST FDSS- 0.00 11.43 10.59 MACKAY QLD 4740 Stumps-M 11.43 94 Holland Street WEST FDSS- 11.70 11.03 MACKAY QLD 4740 Stumps-M 11.70 90 Mogford Street WEST 10.21 10.30 FDSS-SOG-L MACKAY QLD 4740 10.35 14 Douglas Street WEST FDSS- 10.94 10.44 MACKAY QLD 4740 Stumps-L 10.94 92 Holland Street WEST 10.42 10.78 FDDS-L MACKAY QLD 4740 10.88 88 Mogford Street WEST 10.29 10.44 FDSS-SOG-L MACKAY QLD 4740 10.59 16 Douglas Street WEST FDSS- 11.15 10.62 MACKAY QLD 4740 Stumps-S 11.15 90 Holland Street WEST 11.35 10.72 FDSS-SOG-M MACKAY QLD 4740 11.35 86 Mogford Street WEST 10.29 10.29 FDSS-SOG-L MACKAY QLD 4740 10.29 15 Jackson Street WEST FDSS- 0.00 11.58 10.74 MACKAY QLD 4740 Stumps-M 11.58 88 Holland Street WEST 11.03 10.82 FDSS-SOG-L MACKAY QLD 4740 11.03

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-7

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 84 Mogford Street WEST 10.44 10.31 FDSS-SOG-L MACKAY QLD 4740 10.46 13 Jackson Street WEST 11.32 10.58 FDSS-SOG-M MACKAY QLD 4740 11.32 86 Holland Street WEST FDSS- 11.17 10.55 MACKAY QLD 4740 Stumps-M 11.17 82 Mogford Street WEST 10.33 10.28 FDSS-SOG-M MACKAY QLD 4740 10.36 11 Jackson Street WEST FDSS- 11.30 10.63 MACKAY QLD 4740 Stumps-S 11.30 80 Mogford Street WEST 0.00 10.77 10.53 FDSS-SOG-L MACKAY QLD 4740 10.77 9 Jackson Street WEST FDSS- 12.79 10.77 MACKAY QLD 4740 Stumps-M 12.79 1 Chataway Street WEST FDSS- 11.25 10.73 MACKAY QLD 4740 Stumps-M 11.25 79 Mogford Street WEST 10.32 10.68 FDSS-SOG-L MACKAY QLD 4740 10.78 7 Jackson Street WEST FDSS- 0.00 11.52 10.68 MACKAY QLD 4740 Stumps-M 11.52 3 Chataway Street WEST FDSS- 11.15 10.55 MACKAY QLD 4740 Stumps-M 11.15 5 Jackson Street WEST FDSS- 11.49 10.83 MACKAY QLD 4740 Stumps-L 11.49 5 Chataway Street WEST FDSS- 11.13 10.34 MACKAY QLD 4740 Stumps-S 11.13 72 Mogford Street WEST 10.54 10.44 FDSS-SOG-L MACKAY QLD 4740 10.54 83 Mogford Street WEST 10.47 10.33 FDSS-SOG-L MACKAY QLD 4740 10.45 42 Jackson Street WEST 0.00 11.34 11.09 FDSS-SOG-L MACKAY QLD 4740 11.34 4 Jackson Street WEST FDSS- 0.00 11.27 10.67 MACKAY QLD 4740 Stumps-M 11.27 26 Jackson Street WEST FDSS- 11.42 10.70 MACKAY QLD 4740 Stumps-L 11.42 75 Mogford Street WEST 10.82 10.51 FDSS-SOG-L MACKAY QLD 4740 10.82 85 Holland Street WEST 10.89 10.61 FDSS-SOG-L MACKAY QLD 4740 10.89 3 Jackson Street WEST FDSS- 11.24 10.55 MACKAY QLD 4740 Stumps-S 11.24 74 Mogford Street WEST 10.50 10.47 FDSS-SOG-M MACKAY QLD 4740 10.51 1 Jackson Street WEST FDSS- 11.29 10.53 MACKAY QLD 4740 Stumps-M 11.29

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-8

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 55 Mackenzie Street WEST 10.80 10.79 FDDS-S MACKAY QLD 4740 10.80 73 Mogford Street WEST 10.70 10.72 FDSS-SOG-L MACKAY QLD 4740 10.82 80 Holland Street WEST 10.49 10.26 FDSS-SOG-L MACKAY QLD 4740 10.49 71 Mogford Street WEST 10.54 10.70 FDSS-SOG-L MACKAY QLD 4740 10.80 34 Barton Street WEST 10.69 10.59 FDSS-SOG-L MACKAY QLD 4740 10.70 2 Stoneham Street WEST 10.75 10.62 FDSS-SOG-M MACKAY QLD 4740 10.75 32 Barton Street WEST 10.71 10.63 FDSS-SOG-L MACKAY QLD 4740 10.71 2 Chataway Street WEST FDSS- 0.00 11.24 10.21 MACKAY QLD 4740 Stumps-S 11.24 4 Stoneham Street WEST 10.86 10.91 FDSS-SOG-L MACKAY QLD 4740 11.01 30 Barton Street WEST 0.00 11.01 10.77 FDSS-SOG-L MACKAY QLD 4740 11.01 4 Chataway Street WEST FDSS- 10.71 10.16 MACKAY QLD 4740 Stumps-M 10.71 6 Stoneham Street WEST 11.50 10.78 FDSS-SOG-M MACKAY QLD 4740 11.50 6 Chataway Street WEST 12.48 10.30 FDHS-M MACKAY QLD 4740 12.48 20 Barton Street WEST 11.55 11.13 FDDS-L MACKAY QLD 4740 11.55 28 Barton Street WEST 11.43 11.15 FDSS-SOG-L MACKAY QLD 4740 11.43 117 Donaldson Street WEST FDSS- 10.86 10.26 MACKAY QLD 4740 Stumps-S 10.86 115 Donaldson Street WEST 10.46 10.42 FDSS-SOG-L MACKAY QLD 4740 10.48 113 Donaldson Street WEST 10.31 10.29 FDSS-SOG-L MACKAY QLD 4740 10.86 40 Jackson Street WEST FDSS- 11.65 10.80 MACKAY QLD 4740 Stumps-M 11.65 6 Jackson Street WEST 11.19 10.69 FDSS-SOG-M MACKAY QLD 4740 11.19 24 Barton Street WEST 0.00 11.44 11.01 FDDS-M MACKAY QLD 4740 11.44 87 Holland Street WEST 10.87 10.68 FDSS-SOG-L MACKAY QLD 4740 10.87 78 Holland Street WEST FDSS- 10.83 10.10 MACKAY QLD 4740 Stumps-M 10.83

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-9

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 89 Mogford Street WEST 10.53 10.41 FDSS-SOG-S MACKAY QLD 4740 10.53 87 Mogford Street WEST 10.53 10.41 FDSS-SOG-L MACKAY QLD 4740 10.53 8 Chataway Street WEST FDSS- 11.16 10.47 MACKAY QLD 4740 Stumps-M 11.16 10 Chataway Street WEST FDSS- 11.08 10.47 MACKAY QLD 4740 Stumps-S 11.08 12 Chataway Street WEST FDSS- 11.37 10.52 MACKAY QLD 4740 Stumps-M 11.37 14 Chataway Street WEST 10.79 10.67 FDSS-SOG-S MACKAY QLD 4740 10.79 16 Chataway Street WEST FDSS- 11.47 10.77 MACKAY QLD 4740 Stumps-M 11.47 18 Chataway Street WEST FDSS- 11.51 10.71 MACKAY QLD 4740 Stumps-M 11.51 22 Chataway Street WEST FDSS- 10.97 11.01 MACKAY QLD 4740 Stumps-L 11.11 20 Chataway Street WEST FDSS- 11.14 11.04 MACKAY QLD 4740 Stumps-L 11.14 38 Jackson Street WEST 0.00 11.14 10.90 FDSS-SOG-S MACKAY QLD 4740 11.14 8 Jackson Street WEST 0.00 11.24 10.82 FDDS-M MACKAY QLD 4740 11.24 24 Jackson Street WEST FDSS- 11.36 10.76 MACKAY QLD 4740 Stumps-L 11.36 22 Barton Street WEST 11.06 11.10 FDSS-SOG-M MACKAY QLD 4740 11.20 89 Holland Street WEST 10.72 10.75 FDSS-SOG-L MACKAY QLD 4740 10.85 24 Chataway Street WEST FDSS- 11.56 10.80 MACKAY QLD 4740 Stumps-S 11.56 135 Donaldson Street WEST FDSS- 11.35 10.64 MACKAY QLD 4740 Stumps-M 11.35 133 Donaldson Street WEST FDSS- 11.27 10.59 MACKAY QLD 4740 Stumps-M 11.27 131 Donaldson Street WEST FDSS- 11.40 10.59 MACKAY QLD 4740 Stumps-M 11.40 129 Donaldson Street WEST 10.58 10.61 FDDS-M MACKAY QLD 4740 10.71 129 Donaldson Street WEST 10.83 10.47 FDDS-M MACKAY QLD 4740 10.83 125 Donaldson Street WEST FDSS- 10.99 10.50 MACKAY QLD 4740 Stumps-M 10.99 123 Donaldson Street WEST 10.74 10.44 FDSS-SOG-L MACKAY QLD 4740 10.74

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-10

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 121 Donaldson Street WEST FDSS- 10.94 10.37 MACKAY QLD 4740 Stumps-M 10.94 119 Donaldson Street WEST FDSS- 10.91 10.56 MACKAY QLD 4740 Stumps-M 10.91 86 Lagoon Street WEST FDSS- 11.33 11.32 MACKAY QLD 4740 Stumps-L 11.33 10 Jackson Street WEST FDSS- 0.00 10.84 10.83 MACKAY QLD 4740 Stumps-M 10.84 24 Lagoon Street WEST 11.99 11.80 FDSS-SOG-L MACKAY QLD 4740 11.99 27 Barton Street WEST 13.60 11.26 FDHS-M MACKAY QLD 4740 13.60 38 Barton Street WEST 10.84 10.88 FDSS-SOG-L MACKAY QLD 4740 10.98 110 Donaldson Street WEST 10.11 10.08 FDSS-SOG-M MACKAY QLD 4740 10.19 72 Holland Street WEST FDSS- 10.54 9.77 MACKAY QLD 4740 Stumps-S 10.54 68 Holland Street WEST 0.00 10.14 9.71 FDDS-S MACKAY QLD 4740 10.14 47 Mackenzie Street WEST FDSS- 10.70 10.05 MACKAY QLD 4740 Stumps-M 10.70 49 Mackenzie Street WEST 0.00 10.43 10.18 FDSS-SOG-M MACKAY QLD 4740 10.43 84 Lagoon Street WEST FDSS- 12.05 11.48 MACKAY QLD 4740 Stumps-M 12.05 12 Jackson Street WEST 10.98 10.76 FDDS-M MACKAY QLD 4740 10.98 26 Lagoon Street WEST 11.85 11.81 FDSS-SOG-L MACKAY QLD 4740 11.85 25 Barton Street WEST 0.00 11.58 11.33 FDSS-SOG-L MACKAY QLD 4740 11.58 43 Barton Street WEST 11.85 11.12 FDDS-M MACKAY QLD 4740 11.85 118 Donaldson Street WEST FDSS- 10.83 10.15 MACKAY QLD 4740 Stumps-L 10.83 116 Donaldson Street WEST 0.00 10.67 10.25 FDDS-M MACKAY QLD 4740 10.67 114 Donaldson Street WEST FDSS- 9.76 9.76 10.15 MACKAY QLD 4740 Stumps-M 10.75 112 Donaldson Street WEST FDSS- 10.71 10.01 MACKAY QLD 4740 Stumps-M 10.71 120 Donaldson Street WEST FDSS- 10.97 10.53 MACKAY QLD 4740 Stumps-M 10.97 54 Mackenzie Street WEST FDSS- 10.82 10.25 MACKAY QLD 4740 Stumps-M 10.82

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069 AECOM West Mackay Drainage Study – Volume 1 Report C-11

Average Terrestrial Assume Assume Ground Damage Address LiDAR HFL d HFL d HFL LiDAR Category (mAHD) (mAHD) (mAHD) (mAHD) 52 Mackenzie Street WEST FDSS- 10.85 10.25 MACKAY QLD 4740 Stumps-L 10.85 50 Mackenzie Street WEST 10.01 10.17 FDHS-S MACKAY QLD 4740 11.97 48 Mackenzie Street WEST 10.59 10.26 FDSS-SOG-L MACKAY QLD 4740 10.59 82 Lagoon Street WEST FDSS- 12.04 11.33 MACKAY QLD 4740 Stumps-S 12.04 14 Jackson Street WEST 0.00 11.13 10.88 FDSS-SOG-L MACKAY QLD 4740 11.13 23 Barton Street WEST 11.25 11.31 FDDS-M MACKAY QLD 4740 11.41 28 Lagoon Street WEST 0.00 12.02 11.78 FDSS-SOG-M MACKAY QLD 4740 12.02 48 Lagoon Street WEST 11.64 11.53 FDSS-SOG-M MACKAY QLD 4740 11.64 46 Mackenzie Street WEST 11.01 10.23 FDSS-SOG-L MACKAY QLD 4740 11.01 17 Douglas Street WEST FDSS- 11.10 10.38 MACKAY QLD 4740 Stumps-M 11.10 19 Douglas Street WEST FDSS- 11.09 10.68 MACKAY QLD 4740 Stumps-S 11.09 21 Douglas Street WEST FDSS- 11.16 10.42 MACKAY QLD 4740 Stumps-M 11.16 23 Douglas Street WEST 0.00 10.89 10.47 FDDS-S MACKAY QLD 4740 10.89 25 Douglas Street WEST 0.00 12.08 10.47 FDHS-S MACKAY QLD 4740 12.08 126 Donaldson Street WEST FDSS- 0.00 11.36 10.52 MACKAY QLD 4740 Stumps-M 11.36 124 Donaldson Street WEST FDSS- 0.00 11.25 10.41 MACKAY QLD 4740 Stumps-M 11.25 130 Donaldson Street WEST 12.38 10.51 FDHS-S MACKAY QLD 4740 12.38 12 Chataway Street WEST 0.00 0.00 10.63 FDSS-SOG-S MACKAY QLD 4740 10.73 2A Chataway Street WEST FDSS- 0.00 0.00 10.33 MACKAY QLD 4740 Stumps-M 10.93 81 Mogford Street WEST 0.00 0.00 10.66 COM2-M MACKAY QLD 4740 10.76 85 Mogford Street WEST 0.00 0.00 10.59 COM2-S MACKAY QLD 4740 10.69

Revision A – 11-Sep-2019 Prepared for – Mackay Regional Council – ABN: 56 240 712 069