Expert Opinion CAPE OTWAY ROAD AUSTRALIA (‘CORA’) DEVELOPMENT ADVISORY COMMITTEE
COESR Pty Ltd
Panel Hearing: Amendment C125 to the Surf Coast Shire Planning Scheme
January 2020
Report Author: Warwick Bishop Title: Final Report Address of Property: 1300 Cape Otway Road, Modewarre VIC 3240 Report Prepared For: COESR Pty Ltd Instructed By: Mark Naughton (Planning & Property Partners Pty Ltd) Panel Hearing: Amendment C125 to the Surf Coast Shire Planning Scheme Date of Report 22 January 2020 Document Name 20010145_R01_v02e_Expert Witness Report.docx
15 Business Park Drive Notting Hill VIC 3168 Telephone (03) 8526 0800 Fax (03) 9558 9365 ACN 093 377 283
ABN 60 093 377 283
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CONTENTS
1 REPORT AUTHOR 6
2 REPORT CONTRIBUTORS 7
3 SCOPE OF REPORT 8
4 BASIS OF THIS REPORT 9
5 INTRODUCTION 10
6 BACKGROUND 11 6.1 Locality 11 6.2 Proposed Development 12
7 REVIEW OF FLOOD REPORT 14 7.1 Overview 14 7.2 Flooding from Lake Modewarre 14 7.2.1 Flood Modelling Approach 14 7.2.2 Worst-case Scenario 15 7.3 Flooding from the Waterway 16 7.4 Impact of Proposed Development 17 7.4.1 Overview 17 7.4.2 Objective 1 – Flood Safety 17 7.4.3 Objective 2 – Flood Damage 18 7.4.4 Objective 3 - Flood Impact 18 7.4.5 Objective 4 - Waterway and Floodplain Protection 21
8 REVIEW OF INTEGRATED WATER MANAGEMENT PLAN 22 8.1 Overview 22 8.2 Water Sensitive Urban Design Strategy 22 8.3 Impact on Downstream Environment 23 Retarding Basins 25 8.4 8.5 Comprehensive Development Plan Requirements and Guidelines 26
9 ADDITIONAL INVESTIGATIONS 28 9.1 Water Balance Analysis 28
10 DIRECTIONS 31 10.1 Cape Otway Road Australia Development Advisory Committee Stage 1 Report 31 10.2 Cape Otway Road Australia Development Advisory Committee - Directions – 17 Dec 2019 32
11 SUBMISSIONS 34 11.1 Surf Coast Shire Council Submission 35
11.2 Corangamite CMA 36 20010145_R01_v02e_Expert Report.docxWitness
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11.3 DELWP 37
12 CONCLUSIONS AND RECOMMENDATIONS 39 12.1 Conclusions 39 12.1.1 Flooding 39 12.1.2 Integrated Water Management 39 12.2 Recommendations 39
13 DECLARATION 40
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LIST OF FIGURES Figure 6-1 Subject Site and Modewarre Catchments (source: Water Technology, 2019) 12 Figure 6-2 Site Plan (source: Tract, September 2019) 13 Figure 7-1 Worst-case Flood Scenario 16 Figure 7-2 Flood Impacts from CORA Development (Flood Depths), Dec 2019 layout. 19 Figure 7-3 Flood Impacts from CORA Development (Flood Velocities), Dec 2019 layout 20 Figure 9-1 Existing and Post-development Wetland Depth Frequency Curve 29 Figure 9-2 Existing and Post-development Wetland Depth Frequency Curve – by Season 30 Figure 11-1 Berm Re-location (source: Ecology & Heritage Partners) 38
LIST OF TABLES Table 7-1 Flood Safety Hazard Risk 17 Table 8-1 Water Quality Modelling Pre- and Post-Development (inc. external catchments) 24 Table 8-2 CDP Requirements and Guidlines 26 Table 11-1 Summary of Matters Raised in Submissions 34
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1 REPORT AUTHOR Warwick Alistair Bishop Senior Principal Engineer, Director Water Technology Pty Ltd 15 Business Park Drive Notting Hill, VIC 3168
Qualifications:
◼ B.E. (Hons), University of Melbourne, 1993
◼ MEngSci, Monash University, 2000
Affiliations:
◼ Fellow, Institution of Engineers Australia, Chartered Professional Engineer.
◼ Member, River Basin Management Society
◼ Member, Engineers Australia, Victorian Water Engineering Branch Committee
◼ Member, Society for Sustainability and Environmental Engineering of Engineers Australia
◼ Member, Stormwater Victoria
◼ Member, Australian Water Association
◼ Member, International Association for Hydraulic Research
Area of Expertise
Key areas of expertise relevant to this report are summarised below.
◼ Assessment of drainage and flood related issues;
◼ Expert witness for drainage and flood related issues at environmental effects panels,
planning panels and civil hearings.
Statement of Expertise
With my qualifications and experience, I believe that I am well qualified to provide an expert opinion on drainage and flood matters for the Cape Otway Road Australia (‘CORA’) development.
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2 REPORT CONTRIBUTORS Bertrand Salmi Senior Engineer Water Technology Pty Ltd 15 Business Park Drive Notting Hill, VIC 3168
Qualifications:
◼ Bachelor (Hons) of Ecological Sciences (Environmental Sciences), University of Edinburgh 2006
◼ Master of Sciences, Water Resource Engineering Management, Heriot Watt University 2007
Area of Expertise:
Key areas of expertise relevant to this report are summarised below.
◼ Assessment of flood and stormwater management;
◼ Application of GIS.
Scope of contribution:
Bertrand assisted in the preparation of the report, including data review and figure preparation, under my supervision.
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3 SCOPE OF REPORT
In relation to the Amendment C125 to the Surf Coast Shire Planning Scheme, I have been engaged to act as an independent expert on drainage and flooding issues relevant to the elite sport training, tourism and accommodation development in Modewarre, Victoria, known as the Cape Otway Road Australia (‘CORA’) development.
I have been asked to review the material provided to me and prepare an expert witness statement in respect to the CORA development proposal and C125 planning scheme amendment, which:
◼ considers my own opinions, within the limits of my expertise, with respect to the appropriateness of the proposal in relation to all relevant integrated water management considerations;
◼ explains the relevant flood risk in respect to the site and surrounds;
◼ considers the appropriateness of the proposal in respect to proposed flood mitigation measures; and
◼ provides a response to any submissions received from other parties arising from public exhibition.
I understand that the proposal in relation to groundwater management has been considered as part
of the expert witness statement prepared by Mr Andrew Telfer.
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4 BASIS OF THIS REPORT
This report is based on:
◼ Review of Amendment C125 to the Surf Coast Shire Planning Scheme supporting information and technical reports, including:
◼ Development Advisory Committee Stage 1 Report (17 April 2019)
◼ Cape Otway Road Australia Comprehensive Development Plan (17 September 2019)
◼ Flood Report (Water Technology, September 2019)
◼ Integrated Water Management Plan (Water Technology, September 2019)
◼ Land Capability Assessment for Sustainable Irrigation of Recycled Water (Out Task Environmental, August 2018)
◼ Biodiversity Assessment (Ecology & Heritage Partners, September 2019)
◼ Cora Precinct Plan, Concept Masterplan and Landscape Masterplan, Tract, 18 Dec 2019
◼ Review of any additional publicly available information, including:
◼ LiDAR (survey) and VicMap information;
◼ Submissions received in respect to the proposed CORA development and Amendment C125 to the Surf Coast Shire Planning Scheme;
◼ Relevant guidelines and standards, including:
◼ DELWP’s Guidelines for Development in Flood Affected Areas (2019);
◼ Infrastructure Design Manual;
◼ State Rivers and Water Supply Commission Memorandum, Drainage of Lake Modewarre into Thompson’s Creek, 16 September 1977
This report has been prepared in accordance with the relevant procedures and practice notes applied by Planning Panels Victoria on Expert Evidence. I have read the “Guide to Expert Evidence” and am aware of my overriding duty to assist the Panel on matters relevant to my expertise.
I have had no direct input to the development of the proposal or the supporting documents submitted as part of the amendment. Following early discussions with the planning consultant (Tract), prior to Water Technology’s engagement to undertake investigations, my role was Project Director. This is a supporting role (as required) to the Project Manager and did not involve any technical input or review. This role typically becomes active when there are technical or client issues that need my assistance. In this instance there were no such concerns and I remained at “arms length” from the project.
Similarly, my colleague Bertrand Salmi had no involvement in the development of the technical reports. We have therefore undertaken a peer review of the previous Water Technology reports, independent of the previous work, and undertaken further analysis to inform my response to
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5 INTRODUCTION
I have been instructed by Planning & Property Partners on behalf of COESR Pty Ltd to provide expert evidence at the upcoming Panel Hearing in relation to relevant drainage and flooding matters associated with the elite sport, training, tourism and accommodation development in Modewarre, Victoria, known as the Cape Otway Road Australia (‘CORA’) development and associated Amendment C125 to the Surf Coast Shire Planning Scheme.
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6 BACKGROUND 6.1 Locality The subject site is situated to the south-east of Lake Modewarre, as shown in Figure 6-1, and incorporates seven lots. The area, including the subject site and the wider catchment, is predominately farmland and low-density rural living. To the west of the Modewarre catchment is the Barwon River catchment and to the east is the Thompson Creek catchment.
The site is within a drainage catchment contributing inflows to Lake Modewarre and is identified as an area likely to contain Groundwater Dependent Ecosystems (GDE). A number of overlays apply to the site, including:
◼ Land Subject to Inundation Overlay (LSIO) – indicating that the site is flood-prone;
◼ Salinity Management Overlay (SMO) – indicating that the area has risk of salinity impacts; and
◼ Environmental Significance Overlay (ESO) – indicating that there are significant environmental values in or around the site.
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Lake
Modewarre
Figure 6-1 Subject Site and Modewarre Catchments (source: Water Technology, 2019) 6.2 Proposed Development The CORA Comprehensive Development Plan (Tract, September 2019) outlines a long-term plan for the staged development of the land to the south-east of Lake Modewarre into an elite sport, training,
tourism and accommodation development in Modewarre, Victoria. The Comprehensive 20010145_R01_v02e_Expert Report.docxWitness
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Development Plan describes the future layout of these precincts (Figure 6-2) and provides a set of objectives, requirements and guidelines that will inform the development of the project.
Figure 6-2 Site Plan (source: Tract, September 2019) As documented in the Comprehensive Development Plan, CORA aims “to facilitate the restoration and conservation of the wetland by removing historic man-made structures interrupting natural water flows to Lake Modewarre”. CORA also aims to maintain and enhance the local environment through habitat creation, enhancement of local biodiversity and the restoration of natural land systems, through revegetation and water quality treatment.
To meet these water management objectives, a Flood Report and an Integrated Water Management
Plan were prepared, to manage flood risk and stormwater runoff, respectively.
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7 REVIEW OF FLOOD REPORT
7.1 Overview This section documents the findings of my review of the Water Technology Flood Report (September 2019), in particular the potential impact on flood risk and proposed mitigation measures.
The Flood Report investigated flood risk at the site arising from two potential mechanisms:
◼ Backwater flooding from Lake Modewarre due to gradual filling of the lake over extended wet periods and
◼ Fluvial flooding from catchment and waterway flowing adjacent to the development site. Both risks were assessed using detailed hydrological and hydraulic modelling. Design recommendations were then determined from the results.
7.2 Flooding from Lake Modewarre
7.2.1 Flood Modelling Approach The flood report describes Lake Modewarre as a shallow crater lake located near the town of Moriac in South West Victoria, 1 km to the north of the subject site.
The lake is considered a terminal system with no natural outlet. This has resulted in high levels of salinity due to evaporation and no turnover or flushing. Lake Modewarre levels can rise and inundate low lying areas surrounding the lake (including parts of the subject site) due to cumulative volume of runoff (in excess of the evaporation or seepage rate) over periods from days and weeks through to years.
Water Technology developed a detailed water balance model of Lake Modewarre (using Source1) to understand the flood risk from Lake Modewarre at the development site. Source allows the user to input historical rainfall and evapotranspiration data to determine long term flows or, in this case, water levels within a storage (Lake Modewarre).The catchment modelling allowed the potential flood risk from the Lake Modewarre backwater for the proposed development and downstream impacts
to be quantified. Source is an appropriate hydrologic model to investigate this type of situation.
A 104 year period (1911-2015) of daily inflows was modelled. This is a long period and includes several particularly wet decades including the 1950’s, 1970’s and 1990’s. Figure 7-1 shows the Lake Modewarre backwater flood extent for the highest modelled level of 115.37 m AHD in 1977. This inundation extent covers part of the site including the Retail Village
The modelling accounted for a range of parameters, including climate variability, outlet structures and bathymetry. The catchment modelling undertaken allowed for the potential flood risk from Lake Modewarre backwater for the proposed development to be understood and quantified. It also
1 Source is a hydrological and water quality model developed by eWater, used to simulate aspects of water resource systems and support integrated planning, operations and governance from urban, catchment to river
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informed minimum floor levels for at-risk buildings based on the highest modelled flood level (115.37 m AHD in 1977) plus appropriate freeboard (600 mm) resulting in a minimum recommended floor level 116 m AHD.
I consider the approach and modelling methodology to be appropriate to understand flood risk at the site (from Lake Modewarre) as it was based on long-term climatic data and was validated against anecdotal periods of wet and dry years as well as information from the State Rivers and Water Supply Commission report (1977)2, EPA report (2007) and the Corangamite Catchment Management Authority (CCMA).
7.2.2 Worst-case Scenario It has been noted that, as with any floodplain, there is potential for flood levels to exceed the 1% AEP design height. In the case of Lake Modewarre (and the backwater at the subject site), extreme flood heights are dictated by flood storage rather than peak flood flows (which is the case for a typical floodplain area). Lake Modewarre and surrounds can be considered to act like a bath-tub and notionally continue to fill until the “top of the bath” or spill level is reached. This would be at a level of around 118.4 m AHD at the north-east of the lake and notionally spill into the Thompson Creek catchment, flowing towards the coast at Breamlea.
The Cape Otway Road Australia Development Advisory Committee has requested modelling of a potential worst-case scenario of 118.4 metres AHD to understand the potential implications.
Figure 7-1 shows the flood extent under the worst-case scenario, with flood levels set at 118.4 m AHD, compared to the notional 1% AEP flood level extent (115.37 m AHD).This scenario would result in unsafe flood conditions along Cape Otway Road and in some areas of the proposed CORA development. However, there would be higher ground that can be accessed and used as refuge during extreme flood events. Importantly, the slow response time from the catchment (likely to be days or weeks) should provide ample time to evacuate the site and respond to an extreme flood level, in the unlikely event it should be required.
The “worst-case” scenario presents the physical limit of flooding at the site, but not a likely occurrence. I consider it to be an extreme and unrealistic condition, not likely to be achieved and certainly well beyond the accepted design standard. The provision of 600 mm freeboard above the estimated 1% AEP design flood level provides an appropriate factor of safety and allowance for any
potential impacts of rarer flood conditions than the 1% AEP design flood.
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Figure 7-1 Worst-case Flood Scenario
7.3 Flooding from the Waterway There is an unnamed waterway that flows through the subject site, draining from Wensleydale and the Otway National Park. The flood report also considered potential for flooding of the site from a large storm event and associated runoff along this waterway.
A Flood Impact Assessment was undertaken to quantify existing flood risk and assess potential impacts from the development on surrounding properties and environment. The methodology adopted relied on two industry standard modelling software tools commonly used in Victoria:
◼ RORB was used as the hydrological package, in accordance with the latest 2018 Australian Rainfall and Runoff Guidelines; and
◼ TUFLOW was used as the hydraulic modelling software to determine flood levels, depths and velocities across the site.
Water Technology consulted with CCMA through the development of the model, to ensure any relevant background information was incorporated into the analysis.
The 1% AEP water surface level at the site due to waterway flooding was predicted to be 114.5 m AHD, lower than the Lake Modewarre backwater flooding level of 1977. Modelling showed that flood levels at the site were dominated by a backwater effect from the road embankment and culvert at Batsons Road.
In terms of flood levels, it was recommended that the maximum level determined from the Lake Modewarre backwater flooding (115.37 m AHD) be adopted for design purposes. Design flood
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The modelling undertaken for the report incorporated fill of some development areas that are within the existing flood extent, including the Hotel and Retail Village. Subsequently the design intent has been clarified and I understand these buildings will be constructed with pile foundations, reducing flood storage impacts of the development compared to the report.
I consider the approach and modelling methodology to be appropriate to understand riverine flood risk at the site.
7.4 Impact of Proposed Development
7.4.1 Overview The Guidelines for Development in Flood Affected Areas (DELWP, 2019) outlines four key objectives against which proposed developments should be assessed. These objectives aim to:
◼ Protect human life and health and provide safety from flood hazard;
◼ Minimise flood damage to property and associated infrastructure;
◼ Maintain free passage and temporary storage of floodwaters; and
◼ Protect and enhance the environmental features of waterways and floodplains.
These key objectives are discussed further below with reference to the impacts from the proposed development at the subject site, as now envisaged by the September 2019 Comprehensive Development Plan and latest Concept Masterplan (Dec 2019).
7.4.2 Objective 1 – Flood Safety “Protect human life and health, and provide safety from flood hazard” (DELWP, 2019)
Development should not be allowed on properties where the depth and flow of floodwaters would be hazardous to people or vehicles entering and leaving the property. Additionally, the development should be located on land with the lowest overall hazard.
Flood hazard is assessed in terms of flood depth and flood velocity (speed of flow). This can be the depth alone, the velocity alone, or the product of depth and velocity. Flood Risk is categorised by considering criteria detailed in the Guidelines for Development in Flood Affected Areas (DELWP, 2019). Typically, the depth-velocity product is the key criteria, however where depths are shallow the product will tend towards zero and the velocity criteria will dominate. Conversely, where velo- cities are very low, the product will also tend towards zero and the depth criteria dominates.
Table 7-1 Flood Safety Hazard Risk
Flood characteristic Depth (m) Velocity x Depth (m2/s) Velocity (m/s)
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I note that a number of buildings will be located within the floodplain fringe where, under current conditions, the safety hazard criteria would not be met. Provided that finished floor levels are set well above the design flood level (discussed in Section7.2.1) and appropriate access to high ground is provided for all buildings, appropriately safe conditions can be achieved. Additionally, pedestrian interfaces with landscape and waterbodies will incorporate appropriate safety barriers. In addition, Flood hazard can be managed by a Flood Management Plan for the site that establishes appropriate management actions and processes to minimise potential impacts for infrastructure as well people who will work at and visit the site.
These measures are consistent with good floodplain practice for this type of landuse and I understand have been accepted by the responsible floodplain authority, the CCMA.
The flood impact assessment must also consider access to flood-free ground during floods. The risk of people entering floodwater increases if residents/occupants can be physically cut off from their home or workplace, especially during prolonged isolation. This may, in turn, increase the burden on emergency service providers to reach isolated residents/occupants and potentially risk the lives of their staff. As a result, with regards to access safety, criteria exist to ensure safe egress for occupants or emergency services personal in a flood event.
The internal street network will be designed to allow safe and easy access to and from Cape Otway Road and Connies Lane (emergency access only).
I therefore consider that the site safety requirements for the site, including access requirements, have been met.
7.4.3 Objective 2 – Flood Damage “Minimise flood damage to property and associated infrastructure” (DELWP, 2019)
Finished Floor Levels (FFL) must be raised above applicable flood levels, to mitigate against potential flood damage. Freeboard must be added to the applicable 1% AEP design flood level to provide an allowance for uncertainty in the design level and a factor of safety. Freeboard requirements typically range between 300 mm (typically within urban overland flow areas) to 600 mm (typically in areas subject to main stream flooding).
The Flood Report recommends that a freeboard of 600 mm be applied to the design flood level
(115.37 m AHD), meaning that building floor levels should be set at a minimum of 116 m AHD. I note this is consistent with the CDP which also requires a minimum finished floor level of 116 m AHD (Figure 4). Based on these levels I consider that the development will not be at significant risk of damage from flooding nor will it result in flood damage to property and associated infrastructure.
7.4.4 Objective 3 - Flood Impact
“Maintain free passage and temporary storage of floodwaters” (DELWP, 2019)
Detailed hydraulic modelling of the 1% AEP design flood was completed for the site, for existing and proposed conditions. The results from both scenarios were compared to determine if the proposed development has the potential to alter flood conditions through the areas adjacent to, upstream or
downstream of the subject site. This type of analysis is consistent with industry best practice. 20010145_R01_v02e_Expert Report.docxWitness
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7.4.4.1 Flow Diversion and Flood Level Impact
The development should not divert floodwaters or increase flood levels to the detriment of adjoining properties. Hydraulic model results from the report show there are minimal impacts (afflux) on the northern property as a result of the development. Afflux (i.e. increase in flood levels) is limited to site and the waterway/wetland fringes. The results in the report are considered conservative as they assume fill that is not part of the current proposal. The hydraulic model was re-run with the latest development configuration (December 2019) and results presented in Figure 7-2 below. This shows slightly improved results (less impact) compared to the Flood Report.
Figure 7-2 Flood Impacts from CORA Development (Flood Depths), Dec 2019 layout. I note that COESR Pty Ltd has held discussions with owners of the land affected by the minimal
increase in flood levels, at 155 and 105 Batsons Road, Modewarre. Both have acknowledged the “minimal increases” in flood depths and extent and reached an in-principle agreement with COESR Pty Ltd for the proposed floodplain changes (see appendix A of Flood Report).
Given the nature of the development and the extent of flooding, I consider that the development will maintain free passage and temporary storage of floodwaters.
7.4.4.2 Velocity Impacts
The development should not increase the flood velocity on adjoining properties. The hydraulic modelling undertaken suggests there may be small changes in velocity due to the development. Again, the results below are based on an updated model simulation using the latest development
plans (Figure 7-3). This shows that: 20010145_R01_v02e_Expert Report.docxWitness
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◼ The areas where flow paths have been narrowed may see an increase in maximum velocity of 0.2 m/s higher than existing conditions; and
◼ Some locations within the proposed development show decreased flood velocities due to newly created backwater areas.
◼ At the northern extent, the changes are less than 0.05 m/s which is a small increase.
Figure 7-3 Flood Impacts from CORA Development (Flood Velocities), Dec 2019 layout Based on the above, I consider the predicted increases in flood velocities are negligible and will not result in detrimental impact on the waterway, lake environment, or private property.
7.4.4.3 Flood Storage
Proposed developments, including earthworks and buildings, should not result in detrimental loss of flood storage. The flood modelling results in the report show minimal offsite impacts on flood levels. The results also suggest that the potential change to floodplain storage does not cause any significant adverse impacts downstream of the site.
Previous flood storage calculations (Water Technology 2019) indicated there was a loss of storage of less than 20,000 m3 in the 1% AEP event, equating to 2.5% of the total volume of floodplain storage (excluding Lake Modewarre). The use of piers and reduced fill in the latest development plans will reduce the impact of storage loss compared to the Flood Report.
I consider the development proposal provides an acceptable outcome with respect to flood storage. 20010145_R01_v02e_Expert Report.docxWitness
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7.4.5 Objective 4 - Waterway and Floodplain Protection
“Protect and enhance the environmental features of waterways and floodplains” (DELWP, 2019)
Development potentially impacting on waterways and floodplains must look to maintain their environmental functions. Development should therefore (verbatim):
◼ maintain or improve waterway and floodplain conditions;
◼ allow access to maintain riparian corridors;
◼ maintain (by avoidance or offset) the natural function of floodplains and waterways in storing and conveying floodwater; and
◼ retain or improve significant vistas or landscapes within the riparian corridor.
As per the Comprehensive Development Plan, the development aims to:
◼ avoid or minimize effects of redirecting floodwater, reducing flood storage and increasing flood levels and flow velocities;
◼ provide for improvements to health values of the wetlands, natural habitat, environmental flows and water quality; and
The Flood Report for the CORA development demonstrates that the hydrological regime of the site is generally maintained, and any changes will likely be imperceptible and have negligible impact on the environmental and floodplain functions of the existing waterway and Lake Modewarre.
Whilst the development includes an interface with the wetlands and its inherent seasonal variability, the proposed interface will enhance access and connectivity to the water corridor. Revegetation will further improve landscape features within the site.
The works proposed in the Integrated Water Management Plan for the CORA development, discussed in more detail later in this report, also aim to mitigate impact on the environment, improve the quality of water leaving the site through treatment of stormwater runoff and re-establish native vegetation along the floodplain.
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8 REVIEW OF INTEGRATED WATER MANAGEMENT PLAN 8.1 Overview This section documents the finding of my review of Water Technology’s Integrated Water Management Plan (September 2019) and the concept Water Sensitive Urban Design strategy for the proposed development.
An Integrated Water Management Plan (IWMP) was prepared by Water Technology to support the CORA Comprehensive Development Plan (Tract, September 2019). The IWMP includes a stormwater quality management strategy for the proposed development to:
◼ Meet (and exceed) best practice stormwater objectives (as listed in the Infrastructure Design Manual);
◼ Achieve environmentally sustainable outcomes in relation to water sensitive urban design and the environment;
◼ Minimise the impacts upon sensitive environments;
◼ Improve environmental outcomes upon the site through conservation and sustainable land management practices; and
◼ Confirm the development will have no impact on regional groundwater levels.
This section considers the methodology and findings of the Integrated Water Management Plan, focusing on the surface water component of this background report. The groundwater component has been separately considered by Mr Andrew Telfer.
8.2 Water Sensitive Urban Design Strategy For developments across Victoria, the water quality treatment targets established by the Urban Stormwater Best Practice Guidelines (CSIRO, 1999) are applied as a minimum to protect river health values and downstream environment. The removal rate targets for key pollutants are as follows:
◼ 80% of total suspended sediments;
◼ 45% of total nitrogen;
◼ 45% total phosphorous; and
◼ 70% gross pollutants.
It is proposed to meet these water quality objectives through a number of treatment assets:
◼ Gross Pollutant Trap;
◼ Constructed wetlands, including sedimentation basins;
◼ Constructed wetlands are widely used to meet water quality objectives in new development;
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◼ Assets provide conveyance capacity as well as water quality treatment;
◼ Raingardens;
◼ These distributed systems can be incorporated as landscape features;
◼ Rainwater Tanks (RWTs):
◼ Use of RWT aligns with objectives of Water of Victoria (DELWP, 2016) to sustainably manage water resources across Victoria, namely to;
◼ conserve the supply and reduce the use of potable water; and
◼ use alternative water supplies where potable water quality is not required;
◼ Adopted values for water re-use were informed by the COESR Pty Ltd’s Wastewater Concept Design and report (September 2018).
A review of the MUSIC model (Model for Urban Stormwater Improvement Conceptualisation), used to design the water quality treatment performance measures and assess the proposed concept design against Best Practice criteria, showed that Best Practice should be exceeded by the proposed water quality treatment train. I consider that the proposed water quality treatment train (i.e., combination of water quality treatment assets) is appropriate to meet Best Practice objectives. I note that the Infrastructure Design Manual and the State Environment Protection Policy (Waters) refer to the Best Practice Environmental Management Guidelines objectives.
Added benefits will also be achieved with the proposed recycled water scheme design and irrigation management plan. These are to maximise re-use of water on site and minimise discharge of water to the receiving environment.
The concept design adheres to the Infrastructure Design Manual and it would be appropriate for the design of the assets, including exploring the above opportunities, to be finalised at the detailed design stage.
8.3 Impact on Downstream Environment The subject site discharges to environmentally sensitive environments, namely Lake Modewarre and the Brown Swamp Wildlife Reserve. As discussed in Section 11, a number of submissions raised
concerns about potential impacts on the ephemeral wetland, Lake Modewarre and the overall
environmental values of the area.
Whilst the proposed development has the potential to influence the water regime within the catchment, measures have been taken to mitigate any impacts. These are:
◼ The construction of drainage assets, to meet best practice targets:
◼ Increase in surface water runoff volumes will be mitigated by the construction of swales, wetlands and on-lot rainwater tanks;
◼ There will be a significant reduction in pollutant loads to the downstream surface water environment (e.g. Lake Modewarre), as shown in Table 8-1;
◼ Nitrogen, phosphorus and sediment loads to surface water decrease compared to
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◼ The surface water quality modelling (MUSIC) is robust, with results consistent during sensitivity analysis;
◼ A landscape plan for revegetation of the wetland and all water quality works will be developed as part of the proposed development:
◼ Re-vegetation of the waterway reserves will promote indigenous planting, representative of local Ecological Vegetation Classes.
Table 8-1 Water Quality Modelling Pre- and Post-Development (inc. external catchments) Mean Annual Loads Component Existing Post-Development Conditions Total Suspended Surface water 47 33 Solids (t/year) Inc. baseflow 51.8 37.5 Total Phosphorus Surface water 122 93 (Kg/year) Inc. baseflow 148 123 Total Phosphorus Surface water 840 717 (Kg/year) Inc. baseflow 1,070 1,030
The values shown in Table 8-1 relates to surface water only and does not account for fertiliser usage, either under existing agricultural land use or proposed conditions. I understand that nutrients (inc. phosphorus) may be imported or applied to land within the proposed irrigation area to meet plant nutrient requirements because the soils have been assessed as being deficient in phosphorus (Out Task Environmental, August 2018). Monitoring and recycled water quality targets have been specified to ensure loading of salt and nutrients can be managed during operation. Based on these measures, I understand that the risk of nitrogen being mobilised beyond the plant root zone or nitrate being mobilised to groundwater is considered very low (Out Task Environmental, August 2018).
There is an obvious intent to protect and enhance the downstream riparian environments, and minimising any increase of frequency, rate and volume of stormwater runoff leaving the site. This is evident in the Comprehensive Development Plan (see Section 8.5). I note that the water balance provided in the Integrated Water Management Plan does not necessarily consider, in detail, potential impact on the water regime of downstream ephemeral wetlands and Lake Modewarre. Impacts on Lake Modewarre are likely to be negligible, given its large surface area and wider contributing catchment. Additionally, Lake Modewarre could potentially benefit from increased inflows, particularly with the prospect of reduced future inflows to the lake as a result of climate change. DELWP has indicated that:
DELWP would be interested to pursue opportunities resulting from the development proceeding whereby additional water flows to Lake Modewarre could be realised, and active, planned management restored. The exhibited documents do not explore this opportunity, and the proponent has not approached DELWP in this regard. DELWP is open to a discussion on this idea.
The health of the ephemeral wetlands may be more significantly influenced by changed inflows, including seasonality. The current Integrated Water Management Plan does not quantify changes to
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fluctuations within the ephemeral wetlands. I have undertaken additional water balance modelling as described in Section 9.1 to investigate this aspect.
8.4 Retarding Basins The Integrated Water Management Plan also mentions stormwater retarding basins being provided to retard stormwater runoff from the site to pre-development levels. The Integrated Water Management Plan shows three detention basins forming part of the overall stormwater management system, aimed to meet the peak flow targets applicable to the site.
A review of the work to-date by Water Technology indicates that detailed calculations and modelling to support the concept design of these retarding basins have been undertaken and reported in an earlier version of the Flood Report. This section was inadvertently omitted from the exhibited version, when content was split between the Flood Report and the IWMP Report. The methods applied are described below.
The concept design of the retarding basins (i.e. storage volume) were estimated using:
◼ Hydrologic (RORB) modelling using the latest Australian Rainfall and Runoff Guidelines to estimate pre-development discharges (at three locations):
◼ Two outlets to Lake Modewarre;
◼ One outlet to Brown Swamp Wildlife Reserve;
◼ Boyd’s Method calculation to estimate storage volume and footprint.
RORB hydrological modelling was used to establish the site scale hydrological regime under current and future conditions. This aligns with current best practice approaches. A review of these models suggested;
◼ The model schematisation (sub area’s / reaches) was consistent with industry approaches; and
◼ Model parameterisation (loss estimates, impervious fraction estimates, routing parameters) are consistent with industry approaches.
The Boyd’s Method is appropriate to provide preliminary estimates and to give an indication of the approximate size and potential locations where detention could be achieved. It would need to be
refined at the detailed design stage however, these preliminary results indicate that there is sufficient scope within the development to accommodate those three retarding basins and meet peak flow targets applicable to the site.
It is standard practice and as per the current version of the Infrastructure Design Manual (https://www.designmanual.com.au/download-idm) for new developments to detain stormwater on-site (as it currently proposed) to ensure there is no detrimental off-site impact from increased imperviousness areas.
I believe that further details of the retarding concept are not required at this stage as sufficient space is available within the site to accommodate these assets. Specific design details and treatment performance calculations of these basins can be determined at the detailed design stage and subject
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8.5 Comprehensive Development Plan Requirements and Guidelines
It is appropriate for details of the drainage strategy to be reviewed and optimised at the detailed design stage. This is typical practice for development, with detailed design occurring once a planning permit has been granted. Should there be any concerns regarding details of the proposed works, these can be addressed through appropriate conditions.
The Comprehensive Development Plan includes a number of water-related Requirements and Guidelines that will direct the future design of the project. These are listed along with my assessment of how they are addressed within the proposal.
Table 8-2 CDP Requirements and Guidlines CDP Requirements/Guidelines (water) As per Comment Schedule 3 R31. Stormwater runoff from new development yes Documented in IWMP and discussed in this must meet the performance objectives of the report. CSIRO Best Practice Environmental Management Guidelines for Urban Stormwater (1999), unless otherwise approved by the Corangamite Catchment Management Authority and the responsible authority. R32. Quantity of stormwater runoff from yes Not documented in current IWMP or Flood development must not exceed the runoff Report. This is beyond standard development generated from the pre-developed site, unless requirements but is justified based on the otherwise approved by the Corangamite receiving wetland environment. Design outcome Catchment Management Authority and the can be approved by CCMA and Council at responsible authority. detailed stage. Water balance modelling in IWMP and this report shows minimal impact under current design assumptions. R33. Design of stormwater drainage, retarding n/a More based around detailed design elements and quality treatment infrastructure must be to and not explicitly considered in schedule 3. the satisfaction of the Corangamite Catchment Council will be the responsible authority for Management Authority and the responsible drainage assets. Council may seek CCMA advice. authority.
R34. Buildings must be sited so as to sit above n/a Considered in flood report and this report. A the Q100 flood event as determined by the reference to appropriate freeboard would be Corangamite Catchment Management Authority. helpful for completeness although I note the CDP specifies minimum finished floor levels at Figure 4. R35. Any proposed flood mitigation works must yes Flood retarding basins will be finalised at the be designed and undertaken to the satisfaction detailed design stage, consistent with the IWMP of the Corangamite Catchment Management and this report. Authority and the responsible authority. R36. Irrigation of sports fields and landscape yes Covered in Out task Env. Reports and IWMP. areas with treated wastewater must be undertaken in accordance with EPA guidelines
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CDP Requirements/Guidelines (water) As per Comment Schedule 3 R37. The design of the dam associated with the n/a Matter for detailed design and works approval waste water treatment plant must be designed under the environmental protection act. to avoid interaction with groundwater and floodwaters. G44. Development should avoid or minimize n/a Considered and addressed in Flood Report and effects of redirecting floodwater, reducing flood this report. storage and increasing flood levels and flow velocities. G45. Development should provide for n/a Flood and IWMP Reports have focussed primarily improvements to health values of the wetlands, on mitigating any potentially adverse impacts, natural habitat, environmental flows and water although the expansion of ephemeral area due to quality. removal of the berm is discussed. There is potential scope for enhancing downstream water regimes in the future. This would be addressed with relevant authorities at a later date. I also note that aspects related to wetland health are covered by the expert report of Mr Lane. G46. A system of swales and rain gardens within yes Addressed within the IWMP and this report. roadways and car parks should be utilized to achieve stormwater treatment before water enters drainage basins or wetlands.
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9 ADDITIONAL INVESTIGATIONS 9.1 Water Balance Analysis An issue that has been raised by the committee, along with submitters including DELWP is the potential impact of the proposal on the hydrologic regime of the adjacent wetlands. Whist extensive hydrology (Source) and stormwater modelling (MUSIC) has been undertaken, neither of these analyses explored the potential impact of the development on water level fluctuations in the wetlands.
In order to assess what magnitude of change to the existing hydrologic regime might be expected post development I have undertaken some preliminary water balance modelling using MUSIC and a spread-sheet tool. This analysis is independent of the water modelling in the Flood Report. My approach did make use of the existing MUSIC model of the site used for water quality analysis. The basic assumptions this water balance are:
◼ Utilise 10 years of daily rainfall data.
◼ Latest development arrangement with pier construction in the flood fringe areas rather than fill.
◼ Use MUSIC to generate catchment inflows for the existing and post-development conditions
◼ Use a spreadsheet to model the changing volume and surface area of the wetland based on a stage-storage relationship derived from lidar topography.
◼ Apply monthly average evaporation data and seepage data consistent with the MUSIC model.
The model is uncalibrated as there are no measurements to compare levels to. This is a fairly simple model and hence should be considered indicative rather than definitive. The key purpose is to identify trends and in particular the difference between existing and developed conditions. This type of model is typically far more reliable for predicting changes (between scenarios for example) compared to predicting absolute water level values.
The results of the analysis are shown in Figure 9-1 and Figure 9-2. These show the depth frequency curve for the wetland under existing and developed conditions for the whole 10 year period and for a breakdown of the four seasons respectively. The following points can be inferred from these results. Considering a notional depth of say 20 cm for existing conditions:
◼ Over the whole period, this level is exceeded approximately 85% of the time,
◼ In summer, about 70% of the time,
◼ In Autumn, about 80% of the time,
◼ In Winter, about 90% of the time and
◼ In Spring, about 95% of the time.
This highlights the seasonal variation, which is as expected biased towards wetter conditions in Winter and Spring, with drier conditions (shallower depths) in Summer and Autumn.
Considering then the difference between existing and developed conditions, the results suggest a 2-5% increase in frequency of depth thresholds for most levels. For example a 0.3 m depth may be exceeded 53%
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These results suggest that the impact of the proposed development on the hydrologic regime is predicted to be relatively small. Any increase in depth frequency may be able to be further reduced through additional integrated water management measures if these changes were considered significant from an ecological perspective.
I emphasise that this exercise is not intended to accurately predict the actual water level in the wetlands, but does provide some confidence in the magnitude of likely change in inundation frequency that could be expected as a result of the development.
Figure 9-1 Existing and Post-development Wetland Depth Frequency Curve
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`
Figure 9-2 Existing and Post-development Wetland Depth Frequency Curve – by Season 20010145_R01_v02e_Expert Report.docxWitness
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10 DIRECTIONS
10.1 Cape Otway Road Australia Development Advisory Committee Stage 1 Report
The Development Advisory Committee Stage 1 Report (April 2019) reviewed the background documents and made the following recommendations for further information relevant to surface water: 10. Update the Flood Report for public exhibition to verify that local drainage infrastructure and flood pathways can reliably control the height of Lake Modewarre to 114 metres AHD, accounting for both climate change and potential climate change impacts. 11. Provide additional information on the following as part of the background reports for public exhibition: a) Lake Modewarre ecology and groundwater dependent ecosystems (including the values if the Batsons Road culvert is upgraded). b) A water balance model (including nutrients, sediment and salinity). c) Groundwater levels, flows and quality.
These recommendations were, in part, addressed by the Water Technology Flood Report and IWMP Report (Sept 2019). I have been asked to review and respond to these directions. Where responses in the exhibited reports are not clear I have provided further information below. 10. Update the Flood Report for public exhibition to verify that local drainage infrastructure and flood pathways can reliably control the height of Lake Modewarre to 114 metres AHD, accounting for both climate change and potential climate change impacts. Lake Modewarre Levels The Flood Report addresses design flood levels in Lake Modewarre and at the subject site. The long-term hydrologic model establishes the notional 1% AEP design flood height. I understand there is presently no capacity to control levels in Lake Modewarre, which are subject to fluctuations based on weather patterns that influence rainfall and evaporation over scales of days to months. This is no different to the majority of floodplain areas where flood levels are subject to variations based on the natural variation of weather and are not able to be controlled.
In the past there has been infrastructure that allowed for the manipulation of levels in Lake Modewarre
consisting of a tunnel constructed around 1870 which was later decommissioned and replaced by a concrete pipe around 1968 (State Rivers and Water Supply Commission, 1977). This pipe had the capacity to conveyed flows above a level of 113.1 m AHD from the wetland near the northern end of the subject site, east towards Brown Swamp and ultimately into Thompson Creek. It is my understanding through correspondence from the CCMA that this pipe is no longer operational and subsequently regulation of the lake level is not being actively managed. As discussed in Section 7.2.2 there is extremely low risk of lake levels exceeding the recommended design floor level (116 m AHD including freeboard). As an indication, it would require more than 2 floods greater than 1% AEP magnitude in succession to exceed this level and the lake would still be 2 m below the overflow level of 118.3 m. Essentially the size of the lake is large in comparison to the available catchment and there isn’t enough runoff to cause extended periods of elevated levels at a height that would threaten the proposed buildings. As I understand, concerns with lake levels are primarily driven by inundation of
farmland in the 113 to 114 m AHD range, well below the design height for buildings at the subject site. 20010145_R01_v02e_Expert Report.docxWitness
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If extended periods of elevated lake levels are a concern in the future, there is the opportunity to re- activate the drainage culvert to Thompson Creek. This would require a separate approval involving Council, CCMA and effected landowners downstream. If such a scenario occurred it would most likely be driven by landowners concerns with nuisance flooding of farmland around the lake the rather than any concern regarding flooding of the subject site.
Climate Change Impacts on Lake Levels In terms of climate change there are two expected hydrologic consequences of increased mean global temperature in coming decades. These are: ◼ Increased intensity of severe storm rainfall. The spatial and temporal details of this change are not well established in detail at present, however the trend is reliable.
◼ An overall reduction in mean annual rainfall over South-Eastern Australia.
The consequence of these changes is that, whilst individual storms may become more intense, warmer temperatures and increased evapotranspiration will result in a drier catchment and greater rainfall losses over the long term. For rural catchments such as Lake Modewarre, this is expected to result in an overall reduction in runoff. As lake levels are determined primarily by long-term rainfall, this is expected to result in a reduction in design water levels over time rather than an increase.
11. Provide additional information on the following as part of the background reports for public exhibition: a) Lake Modewarre ecology and groundwater dependent ecosystems (including the values if the Batsons Road culvert is upgraded). This matter is not within my area of expertise and I understand is to be addressed by others. b) A water balance model (including nutrients, sediment and salinity). Water balance modelling has been undertaken for the site within the IWMP Report. This consisted of MUSIC hydrologic modelling and associated nutrient and sediment budgets. This work forms part of the Best Practice assessment of stormwater runoff. MUSIC is not able to explicitly model salinity. The surface water being managed on site deals with runoff that already flows from the site, or infiltrates on site. That is, there is no major external input of water such as an external irrigation supply. Hence the overall water balance should remain largely unchanged. As such there is unlikely to be any significant impact on local salinity. Salinity issues associated with groundwater are addressed by others.
c) Groundwater levels, flows and quality. This matter is not within my area of expertise and I understand is to be addressed by others.
10.2 Cape Otway Road Australia Development Advisory Committee - Directions – 17 Dec 2019
The Committee directed that the Proponent must provide a Part B submission that includes its response to the following related to surface water: a) issues raised in submissions, including a detailed response to those raised by Council, DELWP, CFA
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d) (iv) clarification if the wetland is intended to maintain permanent flows or to continue to be subject to temporal influences (vi) modelling of potential worst-case scenario of 118.4 metres AHD to understand implications (vii) potential climate impacts on flood modelling outside of usual ‘wet’ and ‘dry’ spells
I have provided responses to these points as follows. a) issues raised in submissions, including a detailed response to those raised by Council, DELWP, CFA and EPA Victoria. I believe that all issues raised by Council and DELWP have been addressed either in the tabled Flood and IWMP reports or within this report.
d) (iv) Clarification if the wetland is intended to maintain permanent flows or to continue to be subject to temporal influences Most wetlands, whether natural or constructed, tend to be subject to variations in water levels based on seasonality and also in response to shorter term storm events, unless maintained as more permanent ponds for landscape reasons. Many wetlands have what is termed a “permanent pool”. In constructed wetlands this is typically an area of deeper water that will dry out far less often than the shallow section of the system. I would expect any wetlands on the site to be subject to natural variation in water level. This is in accordance with G45 of the CDP with call for development to “… provide for improvements to health values of the wetlands, natural habitat, environmental flows and water quality.” Encouraging temporal variation in water level would be consistent with this guideline. d) (vi) Modelling of potential worst-case scenario of 118.4 metres AHD to understand implications This has been addressed in Section 7.2.2 of this report.
d) (vii) potential climate impacts on flood modelling outside of usual ‘wet’ and ‘dry’ spells This has been addressed in Section 10.1 above.
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11 SUBMISSIONS
The proposed Amendment C125 to the Surf Coast Shire Planning Scheme and CORA development has been assessed against the objections, where relevant to my area of expertise in the following table and sections.
Table 11-1 Summary of Matters Raised in Submissions Concerns Raised Comments on the objectors’ ground Impact on flood risk and adjacent properties. The proposed development meets the objectives of DELWP’s Guidelines for Development in Flood Affected Areas and will not result in unacceptable detrimental impact on adjacent properties (see Section 7.4). Where there are off-site impacts, the proponent has reached an in-principle agreement with adjacent landowners for the proposed floodplain changes and increase in flood levels (<50 mm). Contamination of surface water, including higher With respect to surface water, the downstream habitats nutrient loads and eutrophication risk will not be significantly impacted by the development in terms of water quality. Water quality modelling shows there will be a reduction in pollutant loads to the downstream surface water environment through a comprehensive surface water treatment train.
I am satisfied that sufficient details relating to the design and performance of the proposed water quality assets have been provided for a planning amendment. This gives confidence that necessary treatment performance will be achieved along with appropriate water quality and quantity outcomes. It is appropriate for details to be confirmed at the detailed design stage.
I note that matters related to recycled water re-use and land disposal (e.g. runoff from fertilised sport fields, inherent risks of mismanagement) are outside my area of expertise. Impact of hydrological regime of Lake Modewarre and Although there will be an increase in surface water
Brown Swamp. runoff volumes generated as a result of the development, this increase will be mitigated by the construction of swales, wetlands and on-lot rainwater tanks. A preliminary water balance assessment of hydrologic regime of the wetland adjacent to the site is described in Section 9.1. This suggests the impacts of the development on the wetland water level regime are likely to be minor. Any impact on Lake Modewarre would be expected to be less than this due to the much larger size of the lake, relative to the wetland.
Concerns have also been raised regarding reduced water inflows to Lake Modewarre (due to the reservoir and changing climate) however this is outside the
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Concerns Raised Comments on the objectors’ ground Impact on environmentally sensitive wetlands, including I acknowledge firstly, that matters related to fauna and the depletion and reduction of non-replicable flora are outside my area of expertise. It must be noted ephemeral wetlands and associated biodiversity loss however, that the proposed water quality treatment through excessive disturbance to the area train (i.e. drainage assets) will reduce nutrient loads to surface water compared to existing conditions.
From a topographic and hydrologic regime perspective, the removal of part of the berm and construction of a much smaller wetland close to the retail area will increase the area of ephemeral wetland by reducing the area of permanent water storage. This will restore the overall area to a more natural hydrologic regime.
The ecologic impact of this is outside my area of expertise and a matter for others. Long-term maintenance and monitoring, including for A maintenance plan should be developed that details the “Conservation” area. the sequencing and periods of short, medium and long- term actions, including inspections, and the parties responsible for each action
I note that the Comprehensive Development Plan suggests that the proposed subdivision of land should facilitate the creation of a single title for the environmentally significant area of the Rural Conservation Precinct. Stronger planning controls, such as an S173 agreement or a covenant on title protecting the conservation values of the wetlands may be appropriate to ensure added protection, although current overlays will limit options for any future development in the conservation area regardless.
11.1 Surf Coast Shire Council Submission During their Council Meeting on 26 November 2019, Surf Coast Shire Council resolved to endorse the submission subject to ten additional requirements / items of clarifications, including matters related to biodiversity, infrastructure delivery and water management.
Five matters were related to water as follows:
◼ Clarification regarding the basis for the detention sizing (Water Management Plan):
◼ As discussed in Section 8.4, neither the Flood Report nor the Integrated Water Management Plan include details of the proposed retention basin sizing.
◼ I consider the methodology applied in the preliminary sizing appropriate. Further detailed analysis will be required at the detailed design stage.
◼ Confirmation of obligations for the maintenance of on-site water assets (Water Management Plan):
◼ A detailed maintenance plan (possibly specified by future permit conditions) should
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◼ A maintenance plan should detail the sequencing and periods of short, medium and long-term actions, including inspections, and the party responsible for each action;
◼ This could be further reinforced, if appropriate, with the implementation of a S173 agreement;
◼ Confirmation of mechanisms to ensure that the IWMP recommendations form part of the detailed design and on-ground works (Water Management Plan):
◼ As discussed in Section 8.5, the Comprehensive Development Plan includes a range of Guiding Principles to direct future design of the project;
◼ It is more appropriate for others (planning/legal experts) to recommend which controls can be incorporated to ensure implementation of the IWMP recommendations;
◼ Clarification re: proposed location of the re-located berm and the method to ensure the continuity of natural flows in the wetland (biodiversity):
◼ This is discussed in more details in Section 11.3, with additional details provided as to the re-located berm and associated benefits;
◼ Ultimately, the berm will be decommissioned to remove the artificial waterbody south of the berm, increase the area of ephemeral wetland and some of the material may potentially be re-used to form part of the constructed wetland adjacent to the Retail Village and Hotel;
◼ Identification of critical infrastructure and the mechanisms to be put in place to ensure that they are provided at an early stage and within the Comprehensive Development Zones, i.e., strengthen the reference to infrastructure identification and delivery (Staging and infrastructure):
◼ Council’s comment applies to all infrastructure delivery and as such is a matter for planning;
◼ For drainage infrastructure, it may be required to a significant portion of the drainage assets during the first stage to address concerns regarding flood risk and potential groundwater impact. The detailed engineering design can address the surface water performance of any staged infrastructure plan to the satisfaction of Council.
Overall Council’s comments have been addressed within the report or can be addressed by the
incorporation of planning conditions.
11.2 Corangamite CMA Corangamite CMA indicated that the application under the proposed Comprehensive Development Zone CDZ3 should be accompanied by a flood impact assessment where appropriate (i.e. if the proposal impacts the identified floodplain), providing a similar level of flood control as would apply under a flood overlay (e.g. Land Subject to Inundation). I consider that the Water Technology Flood Report (September 2019) adequately demonstrates that flood risk has been considered and addressed in the proposed development layout. Section 7.4 of this report assesses the proposed development against the Guidelines for Development in Flood Affected Areas (DELWP, 2019), which
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I consider that the flood impact assessment for the site documented in Section 7.4 is robust and minor changes to the development are unlikely to change its conclusion. There will also be opportunities to optimise the design and further reduce flood impacts during the detailed design stage.
The CCMA’s recommendations (shown below) align with the conclusions and recommendations of the Flood Report:
◼ Include the adopted flood level (being a combination of the backwater level of 115.38 metres AHD and waterway flooding for the upstream area) on the incorporated Comprehensive Development Plan and include in the schedule a requirement for referral to the CMA for applications within that area
◼ To accommodate the proposed flood mitigation earthworks (filling) in the Retail and Tourism Precinct, include an exemption to the referral requirement for Buildings and Works on land that has been filled above the flood level in accordance with a previous permit provided no further ground level alteration is proposed
◼ Remove the permit requirement exemption for outbuildings and fences within the flood extent as identified on the CDP and require referral to the CMA as above
11.3 DELWP The Department of Environment, Land Water and Planning submission to the Advisory Committee regarding the CORA development proposal highlights there are key constraints as a result of the site location:
The proximity of the site to Lake Modewarre increases the likelihood of such species using the project area and presents a risk of hydrological impacts, including land salinisation, on surrounding environmental receptors (e.g. Lake Modewarre, Browns Swamp and Thompson Creek).
These constraints are acknowledged in the Comprehensive Development Plan, and the Integrated Water Management Plan details a proposed water quality treatment train to mitigate possible
impacts on these environmental assets.
I note that DELWP considers that it is unclear as to the effect of the re-located berm will have on the wetland:
The Biodiversity Assessment identifies that the artificial berm wall, which currently impedes flows to the north of the site, will be removed. Native vegetation losses have been calculated for removal of the berm to the north of the retail and tourism precinct. It is unclear if the berm will be removed to the west of the precinct (as shown as ‘Area B’ within Appendix 1, Plate 1). If the berm is to be removed at this location, native vegetation within the associated construction footprint area must be assumed lost.
If the berm is to be retained at this location, it is unclear if the hydrology of this area will
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development will hydrologically separate this area from the remainder of the wetland. If the hydrology of this area is likely to be impacted, the area of Current Wetland must be assumed lost.
The existing berm currently acts as a physical barrier between the southern part of the wetland and the creek/Lake Modewarre, as shown in Figure 11-1. Currently, an artificial waterbody is located immediately south of the berm as a result. It is proposed that a significant length of the berm be removed to increase hydraulic connectivity with the main wetland area to the north, re-establishing a wetting-drying regime more consistent with the rest of the wetland. The earth from the existing berm may be used/re-located further south to create a smaller constructed wetland, which will function as a water quality treatment asset to treat runoff from the development.
Existing Berm (to be removed)
Currently Impounded Waterbody
Proposed Constructed
Wetland (indicative only)
Figure 11-1 Berm Re-location (source: Ecology & Heritage Partners) I am satisfied that sufficient details relating to the concept design and performance of the proposed water quality assets have been provided for a planning amendment. This gives confidence that necessary treatment performance will be achieved along with appropriate water quality and quantity outcomes. It will be appropriate for details to be confirmed at the detailed design stage (if the amendment is passed and the development progresses further).
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12 CONCLUSIONS AND RECOMMENDATIONS
With respect to the proposed Amendment C125 to the Surf Coast Shire Planning Scheme and surface water management issues, I make the following conclusions.
12.1 Conclusions
12.1.1 Flooding ◼ The subject site is within the backwater area of Lake Modewarre.
◼ The subject site is liable to flooding from either lake backwater or fluvial flooding from the adjacent waterway.
◼ The 1% AEP design flood attributable to the Lake Modewarre backwater is of a higher elevation than the 1% AEP design flood level from the local waterway.
◼ The 1% AEP design flood level applicable to the site is 115.37 m AHD.
◼ Finished Floor levels for building on the site should cater for 600 mm freeboard and adopt a level of no less than 116 m AHD.
◼ Buildings founded on stumps or piers will have minimal impact on flood storage and due to the low velocity environment will be at low risk of flood damage.
◼ Safe egress from all buildings should be provided via flood free access ways above the 1% AEP design flood level.
12.1.2 Integrated Water Management ◼ The integrated water management concept presented in the IWMP report will provide an appropriate level of on-site stormwater treatment for the proposed development.
◼ The proposed treatment train will exceed best practice standards for stormwater treatment.
◼ The proposed level of stormwater treatment, both quality and quantity will mitigate any potential downstream impacts as a result of the development and protect hydrologic values.
◼ The proposed development will have minor impact on the hydrologic regime of the natural wetland within the conservation zone and Lake Modewarre downstream.
12.2 Recommendations ◼ Detailed design of surface water management measures in accordance with the Comprehensive Development Plan should ensure that appropriately designed assets are delivered.
◼ A maintenance schedule and program should be developed that will ensure ongoing effective operation of all water assets.
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13 DECLARATION
I have made all the inquiries that I believe are desirable and appropriate and that no matters of significance which I regard as relevant have, to my knowledge, been withheld from the Committee.
Warwick A Bishop B.E. (Hons), MEngSci, FIEAust
22 January 2020
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APPENDIX A – CV
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COESR Pty Ltd | January 2020 CAPE OTWAY ROAD AUSTRALIA (‘CORA’) DEVELOPMENT ADVISORY COMMITTEE
WARWICK BISHOP [email protected] | 15 Business Park Drive, Notting Hill VIC 3168 Phone: 03 8526 0800 | 0403 055 338
Director
BE (Hons), MEng Sci (Water)
FIEAust, CPEng, NER
QUALIFICATIONS
◼ Bachelor of Engineering with Honours (Civil), University of Melbourne, 1992
◼ Masters of Engineering Science (Water), Monash University, 1999
AFFILIATIONS
◼ Fellow, Institution of Engineers, Australia, Chartered Professional Engineer
◼ Member, International Association for Hydraulic Research
◼ Member, Australian Water Association
◼ Member, River Basin Management Society
◼ Member, Stormwater Victoria
◼ Member, Engineers Australia Victorian Water Engineering Branch Committee
SUMMARY
Warwick is a Director of Water Technology and has over 25 years’ experience in hydrologic and hydraulic investigations, specialising in the development and calibration of rural and urban hydrologic and hydrodynamic models and their application to flooding, water quality, sediment transport and environmental values. He also has extensive experience in coastal and estuary modelling including wave, current and oil spill investigations. He has worked extensively in the Murray Darling Basin, principally on environmental hydraulic investigations for the Living Murray Program. Warwick was contributed to the most recent revision of Australian Rainfall and Runoff, providing input to the reference document on 2D hydraulic modelling of rural and urban areas. Warwick worked in the Flood Intelligence Unit of SES during the 2011 floods and is regularly called on to provided expert evidence in surface water matters at VCAT and planning panels.
Offices in Melbourne, Brisbane, Adelaide, Perth, Wangaratta, Geelong, Bairnsdale, Stawell | watertech.com.au Page 1
PROFESSIONAL HISTORY
2009 to present Director, Senior Principal Engineer, Water Technology Pty Ltd
2003-2009 Senior Engineer, Water Technology Pty Ltd
2001-2003 Victorian Water Resources Manager, Lawson and Treloar Pty Ltd
1997-2001 Senior Engineer, Lawson and Treloar Pty Ltd
1993-1997 Engineer, Lawson and Treloar Pty Ltd
SPECIALIST AREAS OF EXPERTISE
◼ Wetland, WSUD and water quality investigations
◼ Surface water investigations of urban and rural floodplains, rivers and wetlands
◼ Modelling of flooding, environmental flows, water quality and sediment transport
◼ Urban flood mapping, flood mitigation and stormwater treatment
◼ Integrated Water Management
◼ Investigations of estuary and coastal hydraulics
◼ Expert witness reports
RECENT MAJOR PROJECTS
STORMWATER PROJECTS (FLOODING, DRAINAGE AND WSUD) WATER TECHNOLOGY
Glen Eira WSUD Opportunities – Project director for an options study looking at the potential effectiveness of WSUD measures for flood mitigation. A local case study was undertaken with preliminary hydrologic and hydraulic modelling.
PNG LNG Condensate Fate Modelling – Project Director for hydrologic and hydraulic assessment of potential condensate spill scenarios for Gas Pipeline Development. One and two-dimensional models as well as mixing zone calculations were performed.
Buckland Park Development, Lower Gawler River – Detailed hydraulic investigation of a large new residential area in a floodplain environment. Development of flood mitigation measures including levees and channels.
Inverloch, Broadbeach Resort – Management of flooding issues related to a coastal development on the South Gippsland Coast. Hydrodynamics of the ocean, estuary, creek and township drainage systems have been taken into account to develop an overall flood risk assessment and appropriate land development level. Also included full drainage and WSUD design for the development.
Hoppers Lane (Werribee) – Development of a surface water management strategy for a mixed-use development including full WSUD treatment.
Keysborough South – Development of surface water management strategy for a large residential rezoning. This strategy has been adopted by Melbourne Water as input to their drainage scheme.
Stamford Park – Floodplain and wetland design for an industrial development adjoining a community park area for Knox Council.
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The Strand Traralgon – Development of surface water models and WSUD design (wetlands) to provide treatment for a challenging site, constrained by existing drainage infrastructure and major easements.
Ocean View Lakes Entrance Stormwater Management Plan - Project director for development plan for a residential subdivision. Included design of wetland systems and retarding basin controls.
Cowes WEMP – Project Director in the development of a Water Efficiency Management plan for development in Cowes, use of probabilistic rainfall model PURRS.
Darebin Creek –1d Model (HEC-RAS) construction of waterway and analysis of bridge level assessment for Darebin Creek. Project Director.
Azola Waters, Pakenham – Functional design of Wetlands system for retirement village. Ongoing water quality assessment using various monitoring equipment. Project Manager/Director.
Cuttriss Street Flood investigation, Inverloch – Use of Mike Storm Pipe (Mouse) and two-dimensional (Mike21) linked model for urban storm water flooding. Project Director.
Brookfield Lakes, Bairnsdale, Stormwater Management Plan - Development plan for residential subdivision. Included design of wetland systems and retarding basin controls. Project Director.
Donga Road main drain catchments drainage study (City of Greater Geelong) - GIS analysis and hydraulic modelling of urban floodplain. Use of TUFLOW as predominate 2d/1d modelling package. Project Director.
STORMWATER PROJECTS (FLOODING, DRAINAGE AND WSUD) LAWSON AND TRELOAR
Sanctuary Lakes Water Quality – Management of a detailed water quality investigation including complex eutrophication modelling of the large lake system and analysis of the upstream wetlands
Sandhurst Estate – Management of hydrologic, hydraulic and water quality investigations for a large residential and golf course development in Melbourne’s SE. This investigation included two-dimensional hydraulic analysis, a dynamic-pump system for lake top-up and eutrophication modelling in order to predict future water quality impacts.
Knox Golf Course – Development, calibration and application of a detailed MIKE 21 model of Monbulk Creek/Ferny Creek floodplain to assess flood impacts of a proposed golf course.
Oyster Cove Development, Coomera River QLD – Development of detailed MIKE 21 sub-models to calibrate roughness over residential developments.
Nerang River Floodplain – Major involvement in the development and application of a large, detailed 2- dimensional model of the Nerang River Floodplain. Analysis of impact of developments on flooding and investigation of mitigation options.
Heritage Golf and Country Club – Development of a MIKE 11 model to assess flood conditions in the Yarra River floodplain for design input.
Graceburn Creek, Healesville – development and application of a two-dimensional numerical model of a floodplain for risk assessment, regarding a proposed development. Believed to be the first application of two- dimensional hydraulic modelling on a floodplain in Victoria (1994).
FLOODPLAIN INVESTIGATIONS WATER TECHNOLOGY
Project Director for a hydraulic modelling study of the Pike River floodplain (SA MDB NRM Board). Development and calibration of a MIKE FLOOD model of the floodplain and use to inform the concept design of environmental regulators.
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Project Director for a hydraulic modelling study of the South Australian Katfish Demonstration Reach (DEH). Development and calibration of a MIKE FLOOD model of the floodplain. This model was used to test a number of management scenarios.
Lyndhurst Drainage Strategy - Project Director of modelling waterway works for design of Retarding basins and wetlands for the Lyndhurst drainage scheme. Innovative use of linear waterways/wetlands for storage using two-dimensional hydraulic modelling.
Chowilla Floodplain Hydrodynamic Model – Supervision of the provision of detailed modelling services for this important floodplain system on the Murray River in South Australia, near the Victorian/NSW Border.
Port Fairy Flood Regional Study – A comprehensive review of flood risk to the township of Port Fairy and surrounding areas was undertaken. This included detailed hydrologic and hydraulic modelling, mapping and flood damages analysis. In addition, an extensive investigation of the potential impacts of climate change was undertaken.
Boggy Creek Wetland Review – Hydrologic and hydraulic review of translocated high-value wetland plots in Seaford adjacent to major road development. Working with ecologists to determine appropriate hydrologic regime.
Swan Hill Levee Audit – Investigation of the status of the existing town levee around Swan Hill through the use of a detailed two-dimensional hydraulic model. Assessment of levee system performance and recommendations for future flood mitigation works.
Beaufort Flood Study – Management of a comprehensive hydrologic and hydraulic study of the Beaufort township including investigation of 4 creeks that flow through the town. Resolution of complex design hydrology inputs to the township.
Dennington Flood Study – Detailed two-dimensional hydraulic model developed to describe inundation of the Merri River floodplain and provide planning information for future growth area near Warrnambool in south-west Victoria.
Applying Modelling Tools to Investigate Water Management in the Gunbower Forest – Project manager for the development of a detailed hydraulic model of Gunbower Forest. The model has been calibrated against a number of historic flood events and will be used to assess the effectiveness of a number of potential water management options. These options seek to improve the flooding regime of the forest through the use of environmental flow allocations. The required flooding is determined through a set of ecological objectives. Working closely with ecologists to determine hydrologic regime.
Hydraulic Modelling for Lindsay, Mulcra and Wallpolla Islands – This project involves the development of a linked one and two-dimensional model of these important floodplain and wetland environments that are included as one of the significant environmental assets or “icon sites” along the Murray River. This area has significant environmental values that suffer from reduced flooding due to river regulation. The hydraulic model will be used to test different management scenarios for floodplain improvement.
Murray River Regional Flood Study – Cobram to Tocumwal – Specialist modelling input is being provided for this project with an extensive one and two-dimensional model being developed including the Murray River channel and floodplain. The study area features many man-made controls such as levee banks and irrigation supply channels that dominate the topography. Once established the modelling will be used to develop flood management scenarios on a regional scale.
Investigations into Preferred Water Management Options in Gunbower Forest, 2D Modelling - Project management of the hydraulic modelling of the impact and effectiveness of proposed management options to improve watering of the wetlands and floodplain within Gunbower Forest.
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Glenelg Hopkins CMA Rural Drainage Areas, Water Quality Impact Studies – Hydrologic and water quality analysis of four rural drainage areas specifically to examine the impacts of rural drainage on stream health of the main receiving waters.
Living Murray Hydraulic Investigation, Environmental flow for Barmah Millewa Wetland System – Project and technical management of this significant study within the Murray River system. The project involves the development and calibration of a detailed one and two-dimensional hydrodynamic model of the Barmah Millewa Forest for the purposes of determining the impact and effectiveness of various environmental flow management scenarios.
Lower Gawler Flood Mitigation Study – Detailed hydraulic modelling of the Lower Gawler River floodplain to investigate the effectiveness of various flood mitigation measures. A combined one and two-dimensional hydraulic model was employed.
Scoping Study for Best Management Options for Rural Drainage, Eumeralla and Nullawarre Drainage Areas – Major rural drainage study covering some 18,000 Hectares in south-west Victoria. Processing of ALS/Lidar survey data to assist in detailed hydrologic and hydraulic modelling. Investigation of water quality and environmental impacts of drainage practices and options for implementation of best management practices.
South Warrnambool Flood Study – Management of an urban hydraulic and flood mapping study of a major coastal township. Integration of a variety of survey data sources and a development of a two-dimensional hydrodynamic model.
Geelong Bypass Hydrology and Hydraulics – Management of the investigations of waterway requirements for this major freeway planning study. Numerous crossings analysed with a variety of techniques ranging from simple one-dimensional to fully two-dimensional models.
FLOODPLAIN INVESTIGATIONS LAWSON AND TRELOAR
Point Roadknight Drainage Investigation – Development of a detailed pipe and overland flow model for the assessment of flood extents and investigation of potential mitigation options.
Lake Burrumbeet and Burrumbeet Creek Floodplain Management Plan – Project and technical management of a comprehensive hydrologic and hydraulic modelling study. Assessment of economic, social and environmental impacts also determined.
Morambro Creek Surface Water Allocation – A rigorous hydrological approach was applied to a large catchment in south-east SA utilising a spatially distributed, GIS based hydrologic Model (SWAT). The results will be used in determining future allocation of water rights in the catchment.
Glass’s Creek and Bell Street Flood Mitigation Studies – Detailed hydrology and hydraulic modelling has been undertaken in order to develop appropriate mitigation strategies for two densely developed urban areas in Melbourne. The two-dimensional overland flood models are coupled with detailed pipe network modelling to provide a robust and accurate analysis tool.
Princes Freeway (Pakenham Bypass), Cardinia Creek Crossing – Detailed hydrologic and hydraulic investigation of a proposed crossing of a particularly sensitive creek environment was undertaken. This involved fine-grid two-dimensional modelling.
Little Lang Lang River Waterway Mapping – A combined one and two-dimensional hydrodynamic model of this rural catchment was developed and results integrated into Melbourne Water’s GIS system.
Albury-Wodonga Bypass Hydrology and Hydraulics – Development of a detailed two-dimensional hydraulic model for the assessment of alignment options. The development of detailed hydraulic performance criteria for alignment assessment was also undertaken.
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City of Kingston, Flood Mitigation Assessment – Detailed flood modelling of various mitigation options. Utilising local catchment hydrologic and hydraulic models requiring detailed assessment at the block level combined with complex pump systems.
Breakwater Road Hydrology and Hydraulics – Review of hydrology and detailed hydraulic modelling of a proposed crossing of the Barwon River floodplain. An innovative hydraulic design was necessary in order to provide zero afflux within this sensitive floodplain area.
Shepparton Floodplain Management Investigation for Shepparton City Council – Project management of the hydraulic modelling aspects of the largest rural township flood study undertaken in Victoria.
Princes West Project - Detailed hydrologic and hydraulic assessment of the existing status of the Princes West freeway between Melbourne and Geelong fro VicRoads. Crossing upgrades were designed for varying levels of immunity and various configurations.
Data Consistency Project Stages 7-10 – These projects involved detailed one and two-dimensional urban flood modelling of stormwater surcharges from the various main drain systems.
City of Kingston – Flood Mapping of various locations to supplement Melbourne Water Mapping. Development of local catchment hydrologic and hydraulic models requiring detailed assessment at the block level.
Data Consistency Project Stage 6 – This project involved detailed two-dimensional urban flood modelling of stormwater surcharges from the main drain system. This work formed a pilot study in which Melbourne Water were able to evaluate the benefits of applying two-dimensional modelling to urban areas.
Tambo River Geomorphic Investigation – The 1998 Tambo River event caused significant damage in the floodplain. Specialist two-dimensional hydraulic modelling was undertaken as part of an integrated study approach considering flooding, longer term geomorphological processes and potential waterway management options.
Tuppal and Bullatale Creek Flood Study – Development and calibration of an extensive model of the Tuppal/Bullatale Creek system as well as the Murray and Edward Rivers between Tocumwal and Deniliquin. This model was set-up for the subsequent analysis of floodplain management options through DLWC (NSW).
Strathmerton Route Investigation – Development and calibration of hydraulic models (ranging from steady state backwater to full two-dimensional unsteady models) for subsequent hydraulic design. Both Murray River and floodplain areas have been investigated.
Swan Hill Regional Flood Strategy – Extensive MIKE 11 modelling of Murray/Loddon River system upstream of Swan Hill to assess effects of proposed regional flood strategies.
Traralgon Floodplain Management Study for Shire of Traralgon – As for the Euroa Study, a comprehensive understanding of the flooding mechanisms is being gained through this state of the art fully two dimensional, dynamic flooding investigation.
Euroa Floodplain Management Study for Shire of Strathbogie – This Floodplain Management Study aimed initially at providing a comprehensive understanding of the damaging and complex flooding regime at Euroa, and subsequently at assessing potential flood protection measures (mitigation schemes, both structural and non-structural and flood warning systems). Full two-dimensional hydraulic modelling was undertaken.
Wangaratta Flood Study, Stage 2 – Application of MIKE 11 model to assess various flood mitigation measures.
Cairns Airport Drainage Study – Development and application of a detailed 2-dimensional model of the Cairns Airport and Lower Barron Delta in order to assess flood/cyclone hydrodynamic conditions at the Airport. Analysis of mitigation options.
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Wangaratta Flood Study, Stage 1 – Development and calibration of a MIKE 11 model covering the extensive Ovens/King Rivers floodplain.
Yarra River, Melbourne – Development of a detailed MIKE 21 (two-dimensional) model of the Yarra River to investigate the hydraulic features of a small turning basin/wharf.
Gippsland Lakes System – One-dimensional model developed to analyse the potential impact of sea-level rise on lake levels.
Yarra River, Yarra Glen (VicRoads) – Set up and calibration of both one and two-dimensional models to investigate the impact of a proposed bridge replacement on flood levels.
Lower Loddon River Flood Study – development and calibration of MIKE 11 model covering an extensive floodplain network.
COASTAL/ESTUARINE INVESTIGATIONS WATER TECHNOLOGY
Gippsland Lakes Coastal Hazard Assessment – Project manager for a major hazard assessment project looking at impacts of sea level rise on coastal vulnerability throughout the Gippsland Lakes and Ninety Mile Beach.
Environmental Water Requirements of the Gippsland Lakes – Managed the input of scientific knowledge around hydrodynamics of the lakes and the freshwater/saltwater interface as well as the impacts of reduced freshwater inputs on these flow mechanisms.
Ecological Characterisation of the Gippsland Lakes – Provided hydrodynamic input to a broader characterisation project looking at the various habitats and bio-dependencies in the Gippsland Lakes.
Numerous Coastal Hazard Vulnerability Risk Assessments – assessing the change in risk to coastal inundation and stability due to sea level rise and the resulting change in coastal processes.
COASTAL/ESTUARINE INVESTIGATIONS LAWSON AND TRELOAR
Bass Strait – Three-dimensional model (Delft3D) development and calibration for pipeline design currents prediction.
Tropical Cyclone Thelma, Three-dimensional Current Model – This project involved the set-up and calibration of a three-dimensional hydrodynamic model of the Timor Sea and extraction of currents data.
Mooney Ponds Creek three-dimensional Water Quality Modelling – This project involved modelling of the detailed hydrodynamics of the fresh/salt-water interface in the Yarra River and how this effected the movement of pollutants from storm-water inflows.
Port Catherine Development, W.A. – Detailed three-dimensional hydrodynamic and water quality modelling of a proposed harbour development south of Perth.
Palm Springs Marina, Malaysia – Development of a two-dimensional model to assess effects of marina on local hydraulics.
Corio Bay Sediment Model Verification – Comparison of model predicted and recorded sediment plumes in Corio Bay during channel dredging.
Lake Illawarra/Botany Bay – Application of a two-dimensional water quality model to two large waterways. Long term water quality simulations performed and analysed for risk assessment.
South China Sea – Two and three-dimensional modelling to determine design currents for oil/gas pipelines.
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Manila Bay – Analysis of flood behaviour, dredged sediment impacts and flushing characteristics of a proposed area of reclamation in Manila Bay, using one and two-dimensional models.
West Point Wilson hazardous chemicals storage facility – Environmental Effects Statement. Investigation of proposed facilities effect on nearby coastal processes.
East Coast Armaments Complex – Set up of two-dimensional current and wave models to investigate the impacts of proposed port facility.
Port Hedland – Set up and operation of numerical model to investigate Cyclone driven winds and wave set up.
Western Port – Two-dimensional model investigations of the dispersion of pollutants and the flushing characteristics of Western Port under tidal and wind driven currents.
Oil Spill Modelling/Response – Development of oil spill response procedures to perform real-time modelling of oil slick movements in Bass Strait and Western Port.
Western Port – Set up and calibration of a numerical model for the development of tidal and wind driven current fields as input to oil spill modelling.
Port of Geelong – Application of a two-dimensional numerical model to assess impact of a proposed dredging program on suspended sediment loads in Corio Bay.
Bass Strait – Numerical modelling of the flushing characteristics of Bass Strait over a typical year.
EXPERT WITNESS REPORTS
Adams Creek, Lang Lang – Expert evidence related to rural flooding and drainage issues
Donald, NW Victoria – Expert evidence and analysis of flooding issues related to channel networks on farmland in the Wimmera area
St Georges Road Northcote - Expert advice and modelling of an apartment development within SBO
Duncans Road South Werribee – Review of hydraulic conditions, flooding and drainage for a horticulture area. Provision of expert evidence report.
Nunawading – Expert evidence on flooding issues including modelling, for a multi-storey apartment building in a floodway zone
Hagen Park Bangholme – Expert advice and modelling of drainage issues in SE Melbourne
Noonan Grove Woodend - Expert advice and report on surface water management for a residential subdivision
Industrial Subdivision Shepparton/Mooroopna – Expert advice on drainage and flooding issues for land valuation purposes
Dandenong Valley, Scoresby – Expert modelling and report on flooding issues and development capability for land valuation
Coastal Development Paynesville – Expert report and evidence at VCAT on coastal hazard vulnerability for a residential subdivision
School Site Monbulk – Expert report on drainage issues in the Dandenong Ranges
Broken River, Stewarton – Expert modelling/report and evident at VCAT for a rural flooding issue
Toorak Road South Yarra – VCAT report and evidence in relation to redevelopment of a site within an urban area subject to flooding
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Hopkins River Warrnambool – Flooding and coastal hazard vulnerability export report and VCAT evidence
Apartment Development Port Fairy – Expert report on flooding issues associated with a proposed apartment complex
Port Fairy (2014) – Expert evidence to VCAT on coastal hazard and flooding for a proposed sub-division in Port Fairy.
Kerang East (2014) – Expert evidence to VCAT on flooding issues along Pyramid Creek arising from 2011 floods.
Woodend (2014) – Expert evidence to VCAT regarding flooding from Five Mile Creek and local stormwater impacts at a development site within Woodend.
Port Fairy Planning Scheme Amendment (2014) – Provided Expert Evidence on flooding to Planning Panels Victoria for Moyne Shire.
Victoria Street Richmond (2016) – Expert Evidence to VCAT on flooding issues related to a multi-storey apartment development next to the Yarra River.
Donnybrook/Woodstock PSP (2016) – Expert evidence to panel hearing in relation to drainage issues for a large greenfield development area.
Manningham (2016) – Provision of peer review of modelling and expert advice to City of Manningham regarding a planning scheme amendment to implement SBO layers into their planning scheme.
Amendment C121 Planning Panel - Leneva Baranduda Precinct – expert advice to the City of Wodonga
PUBLICATIONS
CONFERENCE PRESENTATIONS
BISHOP, W.A., McCOWAN, A. D., SUTHERLAND, R. J., WATKINSON, R. J. - “Application of Two- Dimensional Numerical Models to Urban Flood Studies”, 2nd International Symposium on Urban Stormwater Management, Melbourne 1995.
SOMES, N.L.G., BISHOP, W.A., WONG, T.H.F. - “Numerical Simulation of Wetland Hydrodynamics”, MODSIM 97 International Congress on Modelling and Simulation, Hobart.
BISHOP, W.A., COLLINS, N. I., CALLAGHAN, D. P., and CLARK, S. Q. - “Detailed Two-Dimensional Flood Modelling of Urban Developments”, 8th International Conference on Urban Storm Drainage, Sydney 1999.
SOMES, N.L.G., BISHOP, W.A., WONG, T.H.F. - “Numerical Simulation of Wetland Hydrodynamics”, Environment International, Vol. 25, No. 6/7 pp. 773-779, 1999.
BISHOP, W.A. – “Two-dimensional Modelling for Urban Flood Mapping and Drainage Analysis”, Proceedings, Victorian Flood Management Conference, 2001.
BISHOP, W.A. and CATALANO, C.L., “Benefits of Two-dimensional Modelling for Urban Flood Projects”, 6th Conference on Hydraulics in Civil Engineering, Hobart 2001.
McCOWAN, A.D., BERTON, F.M. and BISHOP, W.A. – “The Application of a Three-dimensional Variable Density Model to Assess Water Quality in an Urban Waterway”, 6th Conference on Hydraulics in Civil Engineering, Hobart 2001.
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REHMAN, H.U., ZHANG, S.Y., BISHOP, W.A., BERKFELD, J., “Water Resources Assessment using Soil Water Assessment Tool - A Case Study”, in Proceedings of ICam Catchment Management Conference, University of Western Sydney, Australian Water ssociation, Sydney, 26-28 November 2003.
McMASTER, M.J., PROVIS, D.G., GRAYSON, R.B. & BISHOP, W.A., “Calibration and testing of a hydrodynamic model of the Gippsland Lakes” in Proceedings of MODSIM 2003, Townsville, Australia 14-17 July 2003.
BISHOP, W.A., WOMERSLEY, T.J. & TIERNEY, G, “Flooding Forests - the Hydraulics of Environmental Flows”, Proceedings, 4th Victorian Flood Management Conference, Shepparton 2005.
MUNCASTER, S.H., BISHOP, W.A. and MCCOWAN, A.D., “Design flood estimation in small catchments using two-dimensional hydraulic modelling –A case study”, 30th Hydrology and Water Resources Symposium, Launceston, TAS, December 2006.
BISHOP, W.A. and WOMERSLEY, T.J., “The use of hydraulic models to inform the management of flood dependent ecosystems on the River Murray, South-Eastern Australia”, 6th International Symposium on Ecohydraulics, Christchurch, February 2007.
MUNCASTER, S. H., BISHOP, W. A. and DUGGAN, S.J., “Making the best with what you have - Design flood estimation with and without observed data”, 5th Victorian Flood Management Conference, Warrnambool, October 2007
BISHOP, W.A., CHARTERIS, A.B., MUNCASTER, S.H., WOMERSLEY, T.J., “Impacts of Climate Change on Floodplain Management in Coastal Communities”, 5th Victorian Flood Management Conference, Warrnambool, October 2007.
BISHOP, W.A. and TATE, B. “The Use of Eco-Hydraulics in Managing the River Murray”, 17th QLD Water Symposium, Griffith University, November 2008.
BISHOP, W.A. and WOMERSLEY, T.J., “Port Fairy Regional Flood Study - Dealing with Risk in a Coastal Floodplain”, Jo int 49th Annual Floodplain Management Authorities Conference (NSW) & 6th Biennial Victorian Flood Conference, Albury, February 2009.
BISHOP, W.A., RUSSELL, K.L. and LITTLE, M.J., “Impacts of Sea Level Rise on Flooding in an Estuarine Environment”, Climate Change 2010: Practical Responses to Climate Change Conference, Melbourne, 2010.
MARTIN, J.C., ARROWSMITH, C.L., and BISHOP, W.A., Hydraulic Implications associated with the Placement of Timber Snags in a Developing Anabranch. Proceedings of the Sixth Australian Stream Management Conference, Canberra, Australian Capital Territory, 2011.
BISHOP, W.A., LAW, S.E., NEWTON, J.L., GODFREY, M., “Integrated Water Management Opportunities for Inner Suburban Areas”, WSUD 2013, 8th International Water Senitive Urban Design Conference, Gold Coast, November 2013.
WOMERSLEY, T.J., LEAHY, C., HUDSON, K., ANDERSON, B., KAZAZIC, E., BISHOP, W.A., & MAWER, J., “Proof of concept hydrodynamic model and marine and atmospheric forecast data integration for flood forecasting in the Gippsland Lakes”, 54th Floodplain Management Association Conference, 20-23 May 2014, Deniliquin RSL Club, Deniliquin, NSW
McCOWAN, A.D., LAUCHLAN-ARROWSMITH, C., BISHOP, W.A., “Estimating Future Coastal Inundation and Erosion Hazards”, Australian Coastal Councils Conference, March 2015
COUSLAND, T.J., and BISHOP, W.A., “Transport modelling to verify constructed wetland residence times”, Stormwater 16 – National Stormwater Association Conference, Gold Coast, QLD, September 2016.
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CLARK, S., BISHOP, W., CUNNINGHAM, L., TATE, B., DALY, A., “Utilising Hydraulic Grade Line rather than water surface levels for Flood Planning Levels”, 13th Conference on Hydraulics in Water Engineering, Sydney, Nov 2017.
CLARK, S., CUNNINGHAM, L., TATE, B., DALY, A., BISHOP, W., “Flood Planning Levels: Incorporating residual risk considerations”, 13th Conference on Hydraulics in Water Engineering, Sydney, Nov 2017.
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