Narrawong Coastal Engineering StudyAECOM Narrawong Coastal Engineering Study -...

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Glenelg Shire Council 27 July 2011

Narrawong Coastal Engineering Study

AECOM Narrawong Coastal Engineering Study -

C:\MCollett\Projects\Glenelg Expert Evidence\final report\Narrawong Coastal Eng Final Report.docx Revision 1 - 27 July 2011

Narrawong Coastal Engineering Study

Prepared for

Glenelg Shire Council

Prepared by AECOM Australia Pty Ltd Level 9, 8 Exhibition Street, Melbourne VIC 3000, Australia T +61 3 9653 1234 F +61 3 9654 7117 www.aecom.com ABN 20 093 846 925

27 July 2011

60198406

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Table of Contents 1.0 Introduction 1

1.1 Background 1 2.0 The Site 2

2.1 Previous Investigations 2 2.2 Climate Change 2 2.3 Coastal Processes 3

3.0 Processes Impacting the Study Site 4 3.1 Long-term Coastal Erosion 4

3.1.1 LITDRIFT 4 3.1.2 Aerial Photography 5

3.2 Short-term Coastal Erosion 5 3.3 Recession due to Sea Level Rise 6 3.4 Coastal Inundation (due to storm tide) 7 3.5 Estuarine Inundation (due to river flooding) 8 3.6 Closing of the entrance 8 3.7 Groundwater 9 3.8 Geology 9

4.0 Risk Assessment 10 4.1 Risk Assessment Criteria 10 4.2 Risk Assessment Results 11

5.0 Conclusions 13 6.0 References 14

List of Tables

Table 1 Estimates of shoreline changes from aerial photography.

Table 2 Wave parameters and coastal recession due to storm events

Table 3 Recession due to sea level rise

Table 4 100 year ARI storm level

Table 5 Hydraulic model parameters

Table 6 Flood hazard ratings

Table 7 Likelihood Rating

Table 8 Consequence Rating

Table 9 Risk Assessment Matrix

Table 10 Risk Assessment for Narrawong

Table 11 Coastal inundation and recession due to sea level rise and storm events

List of Figures

Figure 1 Study area and planning zones

Figure 2 Study area and planning overlays

Figure 3 Ground surface elevations at Narrawong

Figure 4 Location of cross-sections for sediment transport computations

Figure 5 Percentage occurrence of Hs (upper panel) and exceedance probability of Hs (lower panel).

Figure 6 Historical shoreline position determined from aerial photography



Figure 7 Beach response from SBEACH at Section 1


Figure 9 Inundation from 100-year ARI flood in 2010

Figure 10 Inundation from 100-year ARI flood in 2100

Figure 11 Water surface elevation from 100-year flood event in 2010

Figure 12 Water surface elevation from 100-year flood event in 2100

Figure 13 Hazard risk in 2010

Figure 14 Hazard risk in 2100

Figure 15 Inundation risk due to closure of entrance

Figure 16 Groundwater bore hole locations

Figure 17 Coastal erosion and flooding risks



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1.0 Introduction

1.1 Background AECOM have been engaged by the Glenelg Shire Council to undertake a coastal engineering assessment of the shoreline adjacent to the proposed development site at Narrawong. The coastal engineering assessment will include investigations of threats from coastal erosion, coastal inundation, and sea level rise due to climate change. The results of the study were used in the preparation of expert evidence for the Planning Panel Advisory Committee for East Street, Narrawong (AECOM, 2011).



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2.0 The Site The study site is located at East Street in Narrawong. Figures1 and 2 show the planning zones and overlays for the site (shown on these figures as the red dotted line labelled ‘Study Area’). The site is currently in the Township Zone (TZ) with an Environmental Significance Overlay (ES04).

The site is located adjacent to the Surry River, approximately 15 km east of Portland. The site is bounded by Portland Bay to the south, Surry River to the west and the Surry River floodplain on the northern boundary. The site is approximately 100 m inland of the current coastline.

Figure 3 shows the ground surface elevation on and around the site. This shows that the northern portion of the site has an elevation of less than 2 m AHD, with the highest elevation on the southern boundary of the site being 8 m AHD.

2.1 Previous Investigations Several previous investigations have been undertaken on the coastal vulnerability of the site. The following references were used in the preparation of this report:

- Coastal Vulnerability Assessment – Lot 18 The Esplanade, Narrawong (Water Technology, 2009)

- Addendum to the Coastal Vulnerability Assessment to address issues discussed with Geoff Brooks, DSE Geelong (Water Technology, September 2010)

- Report on Coastal and Catchment Flooding Issues Associated with the Proposed Dwelling at Lot 18 The Esplanade, Narrawong (Dr Andrew Duncan McCowan, October 2010)

- Victorian Civil and Administrative Tribunal, Printz v Glenelg SC (2010) VCAT 1975 (10 December 2010)

2.2 Climate Change Average temperatures in Australia are expected to rise this century due to elevated atmospheric concentrations of greenhouse gases. This change in temperature is expected to affect a range of other climate variables. The key climate variables that are likely to affect the risk of erosion or inundation of the site include increased rainfall intensity and sea level rise.

Emission scenarios are estimates of the future of greenhouse gases that may be released into the atmosphere. These are based on assumptions about future demographic changes, and the implementation and efficiency of energy policies.

The A1FI scenario is representative of “Rapid economic growth, a global population that peaks mid 21st Century and rapid introduction of new technologies” with “Intensive reliance on fossil fuel energy resources”. This scenario has been adopted for the current investigations.

The Victorian Coastal Strategy recommends implementing a policy of planning for sea level rise of not less than 0.8 metres by 2100. This allowance is consistent with Hunter’s (2009) upper limit of 81.9 cm for the A1FI scenario by 2100. Based on this, the following sea level rise projections have been used:

- 2030 – increase of 0.15 m

- 2070 – increase of 0.47 m

- 2100 – increase of 0.82 m.

AECOM (2010) recommended an increase in rainfall intensity of 43.2% for the 100 year ARI, 24 hour duration flood event, for 2100. This has been used for the modelling results included in this investigation.



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The Victorian Coastal Strategy (2008) recommends that the precautionary principal be applied to planning and management decision-making when considering the risks associated with climate change. The definition of the precautionary principal (as provided in the Victorian Coastal Strategy, 2008) is as follows:

”it is a fundamental component of the concept of ecologically sustainable development (ESD) and has been defined in Principal 15 of the Rio Declaration (1992) United Nations Conference on Environment and Development, Rio, 1992 (the “Rio Declaration”):

“Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation.”

The Precautionary approach has been defined by the Department of Planning and Community Development (http://www.dpcd.vic.gov.au/__data/assets/pdf_file/0003/41727/Coastal_hazards_and_climate_change.pdf) as

“an accepted principal in coastal decision making. It requires decision makers to act having regard to the best available science, knowledge and understanding of the consequences of decisions and in the context of increasing uncertainty, to make decisions that minimise adverse impacts on current and future generations and the environment.”

2.3 Coastal Processes The site is located in close proximity to the coastline and is subject to coastal processes such as:

- Long-term and short-term coastal erosion

- Coastal inundation

- Influence of sea level rise

- Estuarine and riverine flooding

Coastal modelling was undertaken to assess the above phenomena and to assess the potential impacts on the site. The results of the investigation are described in detail in Section 3.



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3.0 Processes Impacting the Study Site

3.1 Long-term Coastal Erosion Long term coastal erosion refers to historical changes in the shoreline position where the shoreline is receding landward over time. It is primarily due to longshore transport including impacts of construction activities along the coast and to a lesser extent, from impacts of severe storms. The longshore transport is the movement of sand parallel to the shore. This can be either erosion or deposition of sand from coastal processes such as tides, waves or currents.

There are several methods of determining the potential longshore transport volumes and recession rates. For this investigation, the following two methods were employed:

- Sediment transport modelling using LITDRIFT

- Aerial photography

The first method consisted of using a well-known software program called LITDRIFT developed by the Danish Hydraulic Institute. This program is used to determine the longshore transport volumes based on the beach profile, wave parameters, bottom friction and sediment properties. The output from LITDRIFTs is an annual volume of sediment transport. This is the volume of sand that the waves can transport along a beach when sand is available to be transported. To determine the rate of recession of the coast line, a full sediment budget is required. When the rate of potential longshore transport increases in the direction of transport, erosion occurs. Conversely, when the rate of potential transport decreases in the direction of transport, then accretion occurs.

The second method of determining long term coastal erosion is to analyse historical aerial photography to determine the changes in shoreline position over time. This can be used to determine a yearly rate of coastal recession (or accretion).

3.1.1 LITDRIFT

The sediment transport model, LITDRIFT is a one-dimensional model that computes the cross-shore distribution of the long shore current, wave height and set-up for a particular coastal profile by solving the long and shore momentum balance equations. Waves can be specified as regular/irregular, unidirectional/directional. Wave input can consist of a single wave condition, time-series of wave conditions or an annual wave climate where the duration of wave incidence is given as a fraction of a year.

The longshore transport potential at the two study sites was determined using LITDRIFT. The model inputs consisted of:

- Cross-shore beach profile

- Annual wave climate (wave height, wave direction and wave period)

- Orientation of the shoreline

Bathymetry for the cross-sectional beach profiles at the two study locations (Figure 4) was extracted from the digital elevation model (DEM). The DEM has been developed by the Department of Sustainability and Environment (DSE) using LiDAR survey data. The surveys were undertaken between November 2008 and April 2009. The vertical resolution of the bathymetric data is ± 0.50 m (95% confidence level) and the horizontal resolution has an accuracy of ± 3.17 m (95% confidence level). A grid size of 5 m was used to define the coastal profile. All longshore computations were undertaken at mean sea level. The shore-normal i.e. the angle (relative to north) perpendicular to the shoreline was determined by measuring the angle using the shoreline extracted from the DEM. The shore-normal at Sections 1 and 2 were 167 and 170 deg respectively.

For the model input, the annual wave climate has been expressed in terms of duration of various wave heights computed from the percentage occurrence obtained from the wave modeling (AECOM, 2010). The wave modeling shows that the 90-95% of the waves approach the study area from the south-south east. Hence a single averaged wave direction for each location was used as input to the model. The percentage occurrence of significant wave heights and their exceedance probability at the two study locations are presented in Figure 5.

Longshore transport calculations for the study site indicate that there is the potential to transport between 200,000 m3 and 250,000 m3 of sediment per year, from the west to the east. Results from AECOM (2010) indicate that the



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potential longshore transport rate on the western bank of the Surry River was in the order of 370,000 m3 per year which is significantly greater than the potential transport of 250,000 m3 at the study site. The reduction of the potential for transport from west to east (the direction of the longshore transport) is indicative of accretion. Observations of accretion have been confirmed at the study site by analysis of historical aerial photographs. However, the sediment transport processes are complex due to the Surry River entering the beach system.

3.1.2 Aerial Photography

Historical changes in the position of shoreline indicate where the coast is receding and where it is accreting. Analysis of aerial photographs where the shoreline is identified by means of cliff lines, water line or vegetation line provides a good indication of shoreline movements over the past several years. The shoreline for different years was digitized from the aerial photographs and overlaid on the site plan using GIS.

For the current study, aerial photographs of 1960; 1972; 1985; and 2009 were geo-referenced into the GIS and analysed. The shoreline was identified as the vegetation line for all photographs except 2009 where LIDAR data was available. In this case, the +2m AHD contour was taken as representative of the shoreline. The shoreline positions at different years were determined and are presented in Table 1. The extracted shorelines from different years are shown in Figure 6.

The analysis indicates that there has been accretion (accumulation of sand) on the beach over the past fifty years. Based on the information shown in Figure 6, the long term coastal accretion is estimated to be in the order of 0.2 m to 0.8 m per year.

Table 12 Estimates of shoreline changes from aerial photography.

Time period Shoreline change (m)

2009-1985 +0.20 m (accretion)

2009-1972 +0.80 m (accretion)

2009-1960 +0.24 m (accretion)

3.2 Short-term Coastal Erosion Short term coastal erosion is the vertical erosion of the beach profile and the horizontal recession of the coastline that occurs during a storm event that lasts for a short duration of generally two to five days. During a large storm event, sand can be moved from the beach, to deeper water. Over time, the beach profile generally returns to the original configuration.

SBEACH was used to determine the recession due to short term coastal erosion. Two terrain profiles were extracted from the survey data provided by the Glenelg Shire Council (a combination of LIDAR data representing the surface elevation above the water level, and bathymetric survey data representing the elevation of the sea bed). Figure 4 shows the location of these two profiles.

SBEACH is an empirical based program that calculates the net cross-shore sand transport rate in four zones from the dune or beach face, through the surf zone and into the offshore past the deepest break-point bar produced by short period incident waves. The wave model is relatively sophisticated and computes shoaling, refraction, breaking, breaking wave re-formation, wave and wind induced set-up and set-down and run-up.

The SBEACH model was set-up using the profile data from the 2009 DEM. A median grain size of 0.2 m based on previous studies (AECOM, 2010) was adopted for both beach profiles. Time-series of water levels, wave height, period and direction and wind speed and direction were input to determine their impact on the current beach profiles. The 100-year Average Recurrence Interval (ARI) storm event was used. Table 2 shows the parameters used in this modelling. These were determined based on SWAN modelling and analysis of recorded water levels.



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Table 13 Wave parameters and coastal recession due to storm events

Section 1 Section 2

Median Hs* (m) 0.94 0.84 Hs* exceeding 12 hr/yr (m) 3.60 3.16 Shore Normal (deg N) 167 160 Average Wave Direction (deg N) 177 171 100 yr ARI Hs* (m) 6.8 6.5 100 yr ARI Storm Recession (at 3.0m AHD) (m) 3.0 1.5

* Hs is the significant wave height, which is the average height of the highest one-third of the waves for the stated interval of time.

Figures 7 and 8 show the results of the SBEACH modelling (changes in beach profile, occurrence of maximum wave height and the maximum surface elevation plus wave set-up) for Section 1 and Section 2 respectively. The red line in the plots represents the initial beach profile while the final beach profile at the end of the modelled storm duration is represented by the brown line. The maximum water surface elevation including wave set-up during the storm duration along the profile is shown by the green line. The maximum wave height during the storm duration is represented by the light blue line.

These results indicate that there is a 3 m recession at a beach elevation of 3.5 m during a large storm event at Section 1 while the beach recedes by 2 m at 3.5 m elevation at Section 2 during a 100-year ARI storm event. As the sand gets moved around along the beach profile by the storm waves, the steeper parts of the beach profile are eroded while there is accretion on the more flatter parts of the beach profile above 0 to1 m AHD.

3.3 Recession due to Sea Level Rise An increase in sea level can have two main impacts on the coastline, one being increased inundation (due to higher sea levels) the other, erosion of unconsolidated (soft) sands. Bruun (1962, 1983) hypothesised that the beach assumed a profile that was in equilibrium with the incoming wave energy, therefore, a rise in sea level would cause the profile to adjust.

The Bruun Rule equation is given by:

=S

(h + B)/L where:

R = shoreline recession due to sea level rise;

S = sea level rise (m)

h = depth of closure

B = berm height; and

L = length of the active zone.

Utilising Bruun’s Rule, it is possible to determine the potential erosion due to sea level rise. This takes into consideration the magnitude of the sea level rise and the profile of the beach. The two sections shown in Figure 4 were used for this calculation.

The depth of closure (depth over which there is significant sediment movement) was determined to be 7.9 m at Section 1 and 7.0 m at Section 2. The length of the active profile is 320 m at Section 1 and 350 m at Section 2.



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The coastal recession from Bruun’s Rule at the two locations for various sea level rise scenarios is shown in Table 3.

Table 14 Recession due to sea level rise

Year Sea level rise Coastal recession at

section 1 Coastal recession at section 2

(m) (m) (m) 2030 0.15 4 5 2070 0.47 13 15 2100 0.82 22 26 2100* 1.20 32 38 * 2100 scenario with sea level rise of 1.2 m has been used for sensitivity testing.

3.4 Coastal Inundation (due to storm tide) The Victorian Coastal Strategy (2008) describes the impacts of tides, storm surge and wave processes on sea level. The term ‘storm tide’ can be used to represent the sea level, with the following components:

- Astronomical tide;

- Storm surge;

- Wave setup; and

- Wave run-up.

Based on the SBEACH modelling, the 100-year ARI storm tide level was determined for the site. Table 4 shows the 100-year ARI storm tide level at the study area under various climate change scenarios.

Table 15 100 year ARI storm level

Year Sea level rise

100 year ARI storm tide level (including sea level rise)

100-year maximum surface elevation (including sea level rise and wave effects)

(m) (m AHD) (m AHD)

2010 0.00 1.10 2.75 2030 0.15 1.25 2.90 2070 0.47 1.57 3.22 2100 0.82 1.92 3.57 2100* 1.20 2.30 3.95 * 2100 scenario with sea level rise of 1.2 m has been used for sensitivity testing.

Due to the proximity of the site to the entrance of the Surry River, it has been assumed (for the purpose of this investigation) that the storm tide level will be translated to the wetlands inside the entrance. The maximum surface elevation in the extreme right-hand column includes the wave set-up at Section 1 of the study site. The 100-year wave height combined with the 100-year storm tide results in the maximum surface elevation which is1.65 m higher than the 100-year storm tide level. The persistence of this high water level will be dependent on the persistence of the extreme high storm wave heights of 6.8 m. If wave heights of greater than 6 m persist for more than the time required for the water to travel upstream through the entrance channel, then there is a likelihood of the low-lying flood-plain and the site getting completely inundated. If the high waves do not persist,



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then the high tidal flow will travel upstream and there is a strong likelihood of the site getting inundated by the 2.3 m storm tide in the year 2100.

3.5 Estuarine Inundation (due to river flooding) Flooding of the Surry River could also impact on the site. Hydrologic and hydraulic modelling was undertaken during a previous investigation (AECOM, 2010). The 100 year ARI flood event was simulated.

The hydraulic model was run for the 100 year ARI flood event, for two scenarios, the first representing 2010 climate conditions, the second representing the 2100 climate conditions. Based on AECOM (2010), the inflow hydrographs were increased by 43.2%, for the 2100 climate change scenario.

Table 5 shows the different modelling parameters used for these scenarios.

Table 16 Hydraulic model parameters

Scenario Total Inflow Downstream water level (m3/s) (m AHD)

2010 83 1.1 2100 119 1.9

Figures 9 and 10 show the 100 year ARI flood depths for the 2010 and 2100 climate change scenarios respectively. Figures 11 and 12 show the predicted 100 year ARI water surface elevations for the 2010 and 2100 climate change scenarios respectively. Figures 13 and 14 show the predicted flood hazard for the 100 year ARI events for the 2010 and 2100 climate change scenarios respectively.

Table 6 shows the categories used for the flood hazard calculations (based on Melbourne Water Guidelines, 2009).

Table 17 Flood hazard ratings

Hazard rating Velocity x depth Flood depth (m2/s) (m)

Low <0.2 <0.2 Low-Moderate 0.2 to 0.4 0.2 to 0.4 Moderate 0.4 to 0.6 0.4 to 0.6 Moderate – High 0.6 to 0.84 0.6 to 0.84 High >0.84 >0.84

Figure 13 shows that the flood hazard can be categorised as being ‘moderate to high’ for most of the site that is inundated during a 100-year ARI flood event under existing conditions.

3.6 Closing of the entrance The Surry River mouth is regularly blocked by sand, due to the high rate of longshore transport and low river flows during certain times of the year. This means that the water from the catchment is trapped behind the sand berm, and cannot flow out. The water level will build up behind this berm until the berm is breached. The berm could be breached by several mechanisms:

- High river flows;

- Coastal process during a severe storm; or

- Artificial breaching.



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An assessment of the recorded water level data provided by the GHCMA, shows that the entrance was blocked for approximately 55% of the time of record (03/10/2006 to 09/03/2010). The highest recorded water levels during this period of record were:

- 09/06/2009 – 1.62 mAHD

- 02/07/2008 – 1.61 mAHD

- 02/06/2007 – 1.57 mAHD

Figure 15 shows the extent of inundation for a water level of 1.62 m AHD, which represents the highest recorded water level for the period of record. Figure 16 also shows the potential extent of inundation for 2030, 2070 and 2100. The elevation for these events was set to 1.62 m AHD plus the appropriate sea level rise.

Unlike the coastal inundation or estuarine inundation, inundation due to closure of the entrance could last for weeks if not months. In 2006/2007, the entrance was closed for a period of over six months. This could have the following adverse impacts on the site:

- Site access may be reduced.

- The portion of site inundated will become water logged, which may have an impact on the vegetation on the site.

- Any assets within the area inundated may have a reduced lifespan due to permanent inundation.

- The performance of septic tanks in the area may be compromised.

With less regular rainfall and more extreme coastal conditions expected due to climate change, it is anticipated that the closure of the entrance will occur more regularly in the future.

3.7 Groundwater There are a number of groundwater bores located adjacent to the site (refer to Figure 16). It is assumed that most of these bores are for residential purposes (potable supply of drinking water).

As the site is located close to the coast line, the current ground water level is expected to be around mean sea level (mAHD). Any increase in sea level due to climate change will be reflected as a similar increase in groundwater levels. The quality of the groundwater (salinity in particular) may also decrease as sea levels rise.

3.8 Geology In addition to the impacts on coastal erosion and inundation, climate change could have the following impacts on the geology of the site.

Wind speed and direction

Any increase in wind speed may lead to an increase in the rate of sediment transport and dune migration. A decrease is estimated to reduce the rate of sediment transport. A change in the dominant wind direction may also lead to a change in the alignment of the dunes.

Precipitation

Changes in rainfall patterns would impact on the vegetation on site. Less regular rainfall may lead to loss of some of the vegetation which stabilise the dunes. This may lead to erosion of the dune system.

Temperature

An increase in temperature may exacerbate the potential for additional weathering processes to occur, i.e. thermal expansion of materials. It may also lead to a change in vegetation type which may lead to a change in the erosion potential for the site.



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4.0 Risk Assessment

4.1 Risk Assessment Criteria The following risk assessment criteria have been applied to this investigation. Note that this has been customised to address the potential for each risk to occur within the timeframes specified in the technical investigations (current, 2030, 2070 and 2100), and the impacts of each risk on the site and functionality of the site.

Table 18 Likelihood Rating

Likelihood Description Almost certain Risk highly likely to occur multiple times Likely Risk likely to occur at least once Possible Risk may occur Unlikely Risk possible but considered unlikely to occur Very unlikely Theoretically possible but unlikely to occur Table 19 Consequence rating

Consequence Description Insignificant Minimal impact on the local area Minor Low impact on the site or its function Moderate Medium impact on the site or its function Major High impact on the site or its function Extreme Very high impact on the site or its function Table 20 Risk assessment matrix

Consequences

Insignificant Minor Moderate Major Extreme

Like

lihoo

d

Almost certain Medium Medium High Extreme Extreme

Likely Medium Medium Medium High Extreme

Possible Low Medium Medium Medium High

Unlikely Low Low Medium Medium Medium

Very unlikely Low Low Low Low Medium



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4.2 Risk Assessment Results Table 21 Risk Assessment for Narrawong

Risk Description Timeline Likelihood Consequences Risk Rating

Long term coastal erosion

Potential for the site to be impacted by long term coastal erosion.

Current Very unlikely Moderate Low

2030 Very unlikely Moderate Low

2070 Very unlikely Major Low


Short term coastal erosion

Potential for the site to be impacted by storm bite (volume of sand lost from the dune and the beach) during a storm event





Cumulative impact of coastal erosion

Considering the potential of the combined effects of long-term and short-term erosion





Recession due to sea level rise

Potential for the site to be impacted on by coastal recession due to sea level rise





Coastal inundation (due to storm tide and wave action)

Potential for the site to be inundated during a 100 year ARI storm tide and 100-year storm wave event.

Current Possible Major Medium

2030 Possible Major Medium

2070 Likely Major High

2100 Likely Major High

Estuarine inundation (due to river flooding)

Potential for the site to be inundated during a 100 year ARI Surry River flood event.

Current Almost Certain Major Extreme

2030 Almost Certain Major Extreme



Joint Probability of flooding and coastal inundation (storm surge)

Potential for the site to be affected by impacts of flooding and storm surge





Closing of the entrance

Potential for the site to be inundated during whist the entrance is closed.







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Risk Description Timeline Likelihood Consequences Risk Rating

Groundwater Potential for seawater intrusion and degradation of groundwater quality

Current Unlikely Moderate Medium

2030 Unlikely Moderate Medium

2070 Unlikely Major Medium

2100 Unlikely Major Medium

Note that these are ‘un-mitigated’ risks. Mitigation measures may be available to reduce either the likelihood or consequences of the risk occurring.



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5.0 Conclusions A summary of results from the coastal modelling investigations is presented in Table 11.

Table 22 Coastal inundation and recession due to sea level rise and storm events

Year Sea level rise (SLR)

Coastal Inundation 100-year maximum surface elevation (including SLR)

Coastal recession due to SLR at Section 1

Coastal recession due to SLR at Section 2

(m) (m AHD) (m) (m) 2030 0.15 2.90 4 5 2070 0.47 3.22 13 15 2100 0.82 3.57 22 26 2100* 1.20 3.95 32 38 * 2100 scenario with sea level rise of 1.2 m has been used for sensitivity testing.

Figure 17 shows the risk of inundation and erosion for the year 2100. The coastal recession due to long-term sea level rise at 2100 is estimated to be 38m while the recession due to short-term storm erosion is on the order of 2-3 m providing a total of approximately 40 m recession. Since the study area is located at a distance of approximately 100 m from the shoreline, the impacts of coastal erosion are relatively low compared with those of estuarine inundation.

However, the risk of coastal inundation (due to storm tide and sea level rise) increases from medium in the current conditions, to high in 2100, due to sea level rise. A significant portion of the site could be inundated during a100 year ARI off-shore storm event.

There is an extreme risk of the site being inundated by a 100 year ARI Surry River flood event under the current climate conditions. Whilst this flood event occurs on average once every one hundred years, the flood hazard plots show that there is high hazard over much of the site for this event. Development in areas subject to inundation by the 100 year ARI flood event should be managed accordingly. Access to the site needs to be above the 100 year ARI flood level.

There is an extreme risk of the site being inundated due to closure of the entrance to the Surry River under the current climate conditions. During the period from October 2006 to March 2010, the entrance was closed approximately 55% of the time. The maximum water level in the Surry River floodplain reached 1.62 mAHD during this time. A portion of the site would be inundated at this water level. During 2006 / 2007, the entrance was closed for a period of over six months. Inundation of site for this portion of time would severely restrict the use and development potential of the land.



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6.0 References AECOM, 2011, “East Street Narrawong – Expert Evidence”, Report presented as expert evidence by Melanie Collett (AECOM) for the Planning Panel Advisory Committee, East Narrawong on behalf of the Glenelg Shire Council.

AECOM, 2010, “Coastal Spaces – Inundation and Erosion – Coastal Engineering Study”, Report prepared for the Glenelg Shire Council, July 2010.

Bruun, P. M., 1962, Sea Level Rise as a cause of beach erosion, Proceedings ASCE Journal of the Waterways and Harbours Division, Volume 88, WW1, pp 117-130, American Society of Civil Engineers.

Bruun, P. M., 1983, Review of conditions for uses of the Bruun Rule of erosion. Journal of Coastal Engineering, 7, No. 1, pp 77-89.

Department of Planning and Community Development (http://www.dpcd.vic.gov.au/__data/assets/pdf_file/0003/41727/Coastal_hazards_and_climate_change.pdf) accessed 15 March 2011.

Hunter J. R., 2009, “Estimating Sea Level Extremes Under Conditions of Uncertain Sea Level Rise”, Climatic Change, 2009.

McCowan, Andrew D., 2010, “Report on Coastal and Catchment Flooding Issues Associated with the Proposed Dwelling at Lot 18 The Esplanade, Narrawong”, Expert Witness Report, October 2010

Victorian Civil and Administrative Tribunal, Prinz v Glenelg SC (2010) VCAT 1975 (10 December 2010)

Victorian Coastal Strategy, 2008.

Water Technology, 2009, “Coastal Vulnerability Assessment – Lot 18 The Esplanade, Narrawong” Report prepared for Alpeggio Veduta Pty Ltd, September 2009

Water Technology , 2010, “Addendum to the Coastal Vulnerability Assessment to address issues discussed with Geoff Brooks, DSE Geelong”, September 2010

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EAST

STRE

ET

CARAVAN PARK ROAD

RLZ

TZ

PPRZ

SURRY RIVE

R

0 100 20050metres

´

1:4,000 (when printed at A3)

A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID

LAST MODIFIEDCREATED BY LF

TCH 13 APR 2011

DATUM GDA 1994, PROJECTION MGA ZONE 54

Study Area and Planning Zones

Data sources:Base Data: (c) DSE 2010, GHCMA(data source)

Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M008_Study_Areas_Planning_Zone.mxd)

1 Figure

Client: Glenelg Shire Council

NARRAWONG COASTAL ENGINEERINGSTUDY

V I C T O R I AV I C T O R I A

N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaCadastre

WatercourseMinor Channel/DrainWaterbodyWetland

Public Park and Recreation Zone [PPRZ]Rural Living Zone [RLZ]Township Zone [TZ]

60198406

NARRAWONG

DPO5

ESO4

ESO1

ESO2

ALLIT

S ROA

D

WINDHAM STREET

WHIS

TLER

S AND

MASO

NS RO

AD

MARKET STREET

PRINCES HIGHWAY

CLAR

KE S T

REE T

THE ESPLANADE S TREET


WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID

LAST MODIFIEDCREATED BY TCH

TCH 13 APR 2011


Study Area and Planning Overlays


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M003_Study_Areas_Planning_Overlays.mxd)

2Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaWaterbodyCadastre

Development Plan Overlay [DPO]Environmental Significance Overlay [ESO]

60198406

SURRY RIVER

NARRAWONG

ALLI T

S RO

AD

WINDHAM STREET

MARKET STREET

WHI

STLE

R S AN

D MA

SONS

ROAD

PRINCES HIGHWAY

CLAR

KE ST

REET

THE ESPLANADE ST REET

CAMBRIDG E STREET

ALBERT ROAD

WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N S T

REET

THE ESPLANADE

EAST

STRE

ET

CARA

V AN PARK ROA

D

VAUGHAN STREET

BRIDGE STREET

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Ground Surface Elevation


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M009_GSE.mxd)

3Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaCadastreWatercourseMinor Channel/Drain

Ground Surface Elevation (mAHD)14 - 1612 - 1410 - 128 - 10

6 - 84 - 62 - 40.503 - 2

60198406

SURRY RIVER

NARRAWONG

ALLI T

S RO

AD

WINDHAM STREET

MARKET STREET

WHI

STLE

R S AN

D MA

SONS

ROAD

PRINCES HIGHWAY

CLAR

KE ST

REET


CAMBRIDG E STREET

ALBERT ROAD

WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N S T

REET

THE ESPLANADE

EAST

STRE

ET

CARA

V AN PARK ROA

D

VAUGHAN STREET

BRIDGE STREET

CROSSSECTION 2

CROSSSECTION 1

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Cross Section Locations


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M012_CS_FloodExtent.mxd)

4Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaCross SectionCadastreWatercourseMinor Channel/Drain


6 - 84 - 62 - 40.503 - 2

60198406

AECOM Narrawong Coastal Engineering Study

Figure 5 Percentage occurrence of Hs (upper panel) and exceedance probability of Hs (lower panel).

0%

2%

4%

6%

8%

10%

12%

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Perc

enta

ge O

ccur

renc

e (%

)

Signifcant Wave Height, Hs (m)

Narrawong

Sec 1

sec 2

0

1

10

0.0 0.1 1.0 10.0 100.0

Sign

ifica

nt W

ave

Hei

ght,

Hs

(m)

Exceedance Probability (%)

Sec 1

Sec 2

SURRY RIVER

NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Historic Coastline


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M007_Coastline.mxd)

6Figure



N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaCadastre

2009 Coastline 2m AHD1972 Coastline

1947 Coastline1960 Coastline1977 Coastline1985 Coastline1992 Coastline2003 Coastline

60198406


AECOM Narrawong Coastal Engineering Study



NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


100 Year ARI Flood in 2010


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M005_Depth.mxd)

9Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy AreaCadastreWatercourseMinor Channel/DrainFlood Extent

100 Year ARI Flood in 2010 (m)Value

High : 2.2

Low : 0

60198406

NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


100 Year ARI Flood in 2100


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M005_Depth.mxd)

10Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


100 Year ARI Flood in 2100 (m)Value

High : 2.2

Low : 0

60198406

NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011



Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M006_WSE.mxd)

11Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


2010 Water Surface Elevation (m)High : 3

Low : 1

Water Surface Elevation 2010

60198406

NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011



Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M006_WSE.mxd)

12Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


2100 Water Surface Elevation (m)High : 3

Low : 1

Water Surface Elevation 2100

60198406

NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Hazard Risk in 2010


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M011_Hazard.mxd)

13Figure



N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


2010 Hazard RiskLowLow - ModerateModerateModerate - HighHigh

60198406


NARRAWONG

ALLIT

S ROA

D

WINDHAM STREET

MARKET STREET

WHIS

TLER

S AND

MASO

NS RO

AD PRINCES HIGHWAY

CLAR

KE S T

REE T



WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N ST

REET

THE ESPLANADE

EAST

STRE

ET

CARAVAN PARK ROAD

VAUGHAN STREET

BRIDGE STREET

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Hazard Risk in 2100


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M011_Hazard.mxd)

14Figure



N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


2100 Hazard RiskLowLow - ModerateModerateModerate - HighHigh

60198406


SURRY RIVER

NARRAWONG

ALLI T

S RO

AD

WINDHAM STREET

MARKET STREET

WHI

STLE

R S AN

D MA

SONS

ROAD

PRINCES HIGHWAY

CLAR

KE ST

REET


CAMBRIDG E STREET

ALBERT ROAD

WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N S T

REET

THE ESPLANADE

EAST

STRE

ET

CARA

V AN PARK ROA

D

VAUGHAN STREET

BRIDGE STREET

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Innundation due to Closure of Entrance


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\M014_Inundation_Entrance_Closure.mxd)

15Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA



6 - 84 - 62 - 40.503 - 2

Innundation due to Closure of Entrance2100 at 2.44m2070 at 2.09m2030 at 1.77m2010 at 1.62m

60198406

#

#

# #

#

# #

# #

#

#

#

#

# # # # ##

#

#

# #

#

# # #

#

#

#

#

#

#

#

##

# #

#

#

## #

# # #

NARRAWONGPRINCES HIGHWAY

NOLA

N STR

EETVAUGHAN STREET

BRIDGE STREET

CARAVAN

PARK

ROAD

WINDHAM STREET

THE ESPLANADE

CARAVAN PARK ROAD

MARKET STREET

CLAR

KE ST

REET

THE ESPLANADE STREET

CAMBR IDGE S TREE T

ALBERT R OAD

E AST

STR E

ET

10m

10m

10m

10m

10m

10m

10m

10m10m

10m

84544

8439684447

8452584669

84462

142554

84439 8453584536

8464984537

13273584457

84473

84472 84538

84571

84454

84471133983

8466484500

84440

84446

84529

84495 8443084450

8444284572

84429

84493

84621

84443

139872

84546

119583

84463 84435 84528

84527

84498

84444 84559

84539

SURRY RIVE

R

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID

LAST MODIFIEDCREATED BY

60198406LHTCH 14 APR 2011


Groundwater Bore Location Map


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M004_Data_BoreHoles_DSE.mxd)

16Figure


NARRAWONG COASTAL ENGINEERINGSTUDY - GROUNDWATER INVESTIGATION


N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA

LegendStudy Area Extent

# Private BoresCadastre

ElevationContours (10m interval)

HydrographyWatercourseMinor Channel/DrainLakeWetland/Swamp

Parks and RecreationPublic Conservation and Resource ZonePublic Park and Recreation Zone

SURRY RIVER

NARRAWONG

ALLI T

S RO

AD

WINDHAM STREET

MARKET STREET

WHI

STLE

R S AN

D MA

SONS

ROAD

PRINCES HIGHWAY

CLAR

KE ST

REET


CAMBRIDG E STREET

ALBERT ROAD

WINDHAM STREET

THE ESPLANADE

WINDHAM STREET

NOLA

N S T

REET

THE ESPLANADE

EAST

STRE

ET

CARA

V AN PARK ROA

D

VAUGHAN STREET

BRIDGE STREET

0 100 20050metres

´


A3 size

AECO

M doe

s not w

arrant

the ac

curacy

or com

pleten

ess of

inform

ation d

isplay

ed in t

his ma

p and

any pe

rson u

sing it

does

so at t

heir o

wn ris

k. A

ECOM

shall

bear n

o resp

onsibil

ity or

liability

for an

y erro

rs, fau

lts, de

fects,

or om

ission

s in the

inform

ation.

www.aecom.com

PROJECT ID


TCH 14 APR 2011


Coastal Erosion and Flooding Risks


Map Document: (L:\work\SIT2\Proposals\2010\20101126_Portland_Assessment\06_Maps\M013_Coastal_Erosion_Risk.mxd)

17Figure




N S WN S W

MELBOURNESTUDY AREA

PORTLAND!(

!( WARRNAMBOOL!(

GEELONG!(

HAMILTON

SASA


Hazard Lines2009 Baseline2100 Coastal Erosion Risk2100 Flooding


6 - 84 - 62 - 40.503 - 2

60198406

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