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April, 2015

Bellingen Shire Estuary Inundation MappingFinal Report

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Bellingen Shire Estuary Inundation Mapping Bellingen Shire Estuary Inundation Mapping Bellingen Shire Estuary Inundation Mapping

Prepared for: Bellingen Shire Council

Prepared by: BMT WBM Pty Ltd (Member of the BMT group of companies)

Offices Brisbane Denver London Mackay Melbourne Newcastle Perth Sydney Vancouver


Document Control Sheet

BMT WBM Pty Ltd 126 Belford Street Broadmeadow NSW 2292 Australia PO Box 266 Broadmeadow NSW 2292 Tel: +61 2 4940 8882 Fax: +61 2 4940 8887 ABN 54 010 830 421 www.bmtwbm.com.au

Document: R.N20222.001.02.docx

Title: Bellingen Shire Estuary Inundation Mapping

Project Manager: Luke Kidd

Author: Luke Kidd, Rohan Hudson, Suanne Richards, Paul Donaldson

Client: Bellingen Shire Council

Client Contact: Daan Schiebaan

Client Reference:

Synopsis: This document outlines Sea Level Rise Mapping undertaken for the Bellingen Shire Estuary which includes an estuary inundation risk assessment for present and future timeframes of 2050 and 2100. A register of the level of risks to various land and assets within the study area and suggested potential mitigation options to reduce the level of future risk due to SLR is also provided.

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Acknowledgement BMT WBM Pty Ltd (Member of the BMT group of companies) has prepared this document for Bellingen Shire Council with financial assistance from the NSW Government through its Estuary Management Program. This document does not necessarily represent the opinions of the NSW Government or the Office of Environment and Heritage.

Bellingen Shire Estuary Inundation Mapping i Executive Summary


Executive Summary

The Bellingen Shire Estuary Inundation Mapping Study describes tidal inundation extents for both typical

ocean conditions and severe storm events under existing and future mean sea level conditions. The maps

and suggested mitigation options produced as part of the project can be used by Bellingen Shire Council

(BSC) in preparation for and adaptation to rising sea levels. With appropriate planning, social disruption,

economic loss and environmental impacts can be minimised.

This study complements the Bellingen Coastal Zone Hazard Study (CZMS) and Management Plan (CZMP)

which defined the present and future coastal hazards for the Bellingen study area in accordance with the

NSW Coastal Protection Act, 1979 and associated Guidelines for Preparing Coastal Zone Management

Plans (OEH, 2013). A risk based assessment was undertaken of the predicted sea level rise inundation

hazard and their consequences. By utilising the same methodology, the outcomes of this study can be easily

integrated within the CZMP at a later stage.

Study Area

The Bellingen Shire Local Government Area (LGA) is located on the NSW Mid North Coast and includes

some 15 km of coastline extending from Oyster Creek in the south to Tuckers Rocks in the north.

Three notable coastal entrances are situated along the Bellingen coastline, namely Oyster Creek and

Dalhousie Creek (which are small creeks intermittently open to the ocean) and the larger Bellinger / Kalang

River with its partially trained entrance at Urunga.

The floodplains of the Kalang and Bellinger Rivers between Urunga and Mylestom are low-lying and subject

to the potential inundation impacts of climate change and sea level rise. The potential impact to both private

and public land as well as assets within the BSC LGA is significant.

Study Objectives

The objective of the study is to systematically and comprehensively identify the extent of sea level rise risks

facing the BSC LGA by determining the flood levels for immediate and future sea level rise scenarios. Using

model results including the estuarine inundation depth and extent, the study seeks to identify the areas of

current and future tidal inundation and assess the risk to infrastructure (built environment) and ecological

assets within the Bellinger-Kalang Estuary.

Estuary Inundation Modelling

The impact of sea level rise on areas was assessed by modelling a range of design tidal inundation events

on the three estuaries located in the LGA, namely the Bellinger-Kalang Estuary, Dalhousie Creek and Oyster

Creek. An existing TUFLOW flood model of the Bellinger and Kalang River was reviewed and updated to

determine design tidal inundation levels and extents for current and future sea level rise conditions. For the

smaller Dalhousie Creek and Oyster Creeks ICOLLs, a bathtub modelling approach was used to determine

design tidal inundation extents.

Estuary inundation modelling is presented for twenty (20) design runs including four (4) design events (spring

tide; king tide; 20-year Average Recurrence Interval; and 100-year Average Recurrence Interval) for five (5)

different sea level rise scenarios (i.e. 0.0 metres, +0.4 metres, +0.7 metres, +0.9 metres and +1.4 metres

Bellingen Shire Estuary Inundation Mapping ii Executive Summary


above Australian Height Datum (m AHD). Maps showing the approximate inundation extent for key localities

in the study area are provided in Appendix B.

Estuary Ecological Modelling

In order to better understand the ecological impact(s) of sea level rise, statistics of longer term water level

and salinity variations were obtained by developing a new estuary (hydrodynamic) model capable of

simulating a continuous period of estuary hydrodynamics (water levels and salinity concentration). In addition

to the estuary model, a catchment (hydrologic) model was required to estimate freshwater inputs to the

estuary which influence the water levels and longitudinal salinity variations along the Bellinger and Kalang

Rivers.

Comparing between sea level rise scenarios, the modelling demonstrates that 10 km upstream of the

entrance (Bellinger River at Raleigh and Kalang River near Newry Island), and with a sea level rise of

1.4 metres, the median water level would be notably greater (approximately 0.3 metres) than the maximum

water level expected under existing tidal conditions. Of somewhat more importance, the minimum water level

at that same location and sea level rise is 1 metre higher than the lowest water level estimated for the

existing (without sea level rise) condition. A water level of this magnitude would only be exceeded about 5%

of the time under existing conditions, which typically occurs during large spring or king tides.

Scenario modelling shows that low salinity is controlled by large fluvial flow events from the upstream

catchment, which can maintain freshwater conditions along the full length of the two river systems down to

the estuary mouth. The relative position of minimum salinity along the two rivers is comparable between the

different sea level rise scenarios. However, the change in the relative position and slope of the longitudinal

salinity profiles between the different scenarios shows that the ingress of saltwater will increase with sea

level rise, more so along the Kalang River than the Bellinger River, which is partly due to the smaller

catchment area and lower river discharge occurring along that reach of the estuary.

Risk Assessment Methods

A risk based approach was applied to this study, to guide the development of management options. Risk is

defined as the combination of ‘likelihood’ and ‘consequence’ for an event. The study defines various

‘likelihood’ scenarios for estuary inundation, for present day and future (2050 and 2100) timeframes. A key

component of this study was to determine ‘consequence’ of inundation caused by sea level rise on the

affected land and assets.

The sea level rise inundation hazard consequence was guided by the outcomes of a formal Risk Assessment

Workshop conducted during the preparation of the CZMP, professional judgement and local knowledge of

the study area.

The level of risk to specific land and assets was derived from the combination of the ‘consequence’ assigned

to land / assets and the ‘likelihood’ of the hazards. The level of risk was tabulated as a risk register for

important assets. ‘High’ and ‘extreme’ risk levels are considered to be intolerable, whereas ‘medium’ and

’low’ levels of risk are defined as tolerable and acceptable, respectively.

Bellingen Shire Estuary Inundation Mapping iii Executive Summary


Risk Assessment Outcomes

From the risk assessment process, the assets and land found to have intolerable levels of risk under the

present and future (2050 and 2100) timeframes were identified and subsequently prioritised for

management.

Significant occurrences of residential, rural, primary production and recreation also experiencing intolerable

levels of risk under present and future timeframes may occur. Forestry, primary production and rural land is

typically at risk at many of the suburbs and most susceptible to potential sea level rise inundation due to its

proximity to the main estuary waterways. At some localities such as Bellingen and Raleigh, low-lying sewer

and stormwater services (i.e. rising main and drainage main and waste management centre) are at high risk.

The suburbs of Mylestom, Repton and Bellingen may experience the smallest inundation impact for the

immediate, 2050 and 2100 timeframes with the vast majority of asset categories not at risk. Residential

development at Urunga may be at risk under future scenarios compared to the immediate timeframe. At all

other suburbs, residential development is not at risk from sea level rise inundation for the immediate and

2050 timeframes although a medium risk is calculated at Raleigh for the 2100 timeframe.

Significant inundation of primary production land which is already at risk for the immediate timeframe may

increase further as a consequence of projected sea level rise for the 2050 and 2100 timeframes. Throughout

the study area, there is a variety of natural assets including Endangered Ecological Communities (EEC) of

coastal saltmarsh, freshwater wetland, littoral rainforest, lowland rainforest, subtropical coastal floodplain

forest and swamp sclerophyll forest. Ecological communities are by far at the greatest risk, particularly at

Urunga Lagoon where the largest continuous area of coastal saltmarsh is present.

Inundation Risk Management Approach

Defining risk levels at various timeframes has been used to appropriately develop and prioritise risk

management treatment options. Extreme and high risks that occur in the present day require management

immediately as a priority. For future extreme and high risks, it is more important to determine a reliable

‘trigger’ for action. The trigger must be set to enable enough time to gain approvals, raise funds and

implement the action, prior to the hazard impact occurring.

While the exact option for managing the future risks may not need to be refined now, it is important to

determine the long-term management intent for assets at risk, for example, relocation, redesign, protection,

abandonment and so on. In the interim, until impacts become imminent, management actions that have

minimal adverse impacts and / or improve the ability to treat other risks in the future should be pursued.

These have been termed ‘No regrets’ actions.

Risk Management Options

Risk management options recommended for managing the mapped estuary inundation hazard are provided.

The options are collated based on the multi criteria analysis conducted in the Coastal Zone Management

Study (CZMS), and refined to suit the needs of the assets types in the context of Bellingen Shire. Detailed

descriptions of all management options are provided in Appendix E of the Bellingen CZMS (2014), although

those considered most suitable to the management of sea level rise inundation in the study area are

discussed, namely:

• Monitoring to collect better information regarding coastal processes and to determine when a risk is

approaching;

Bellingen Shire Estuary Inundation Mapping iv Executive Summary


• Asset Management Planning to incorporate the likelihood of the coastal hazards to impact upon

Council’s assets;

• Audit of Existing Council Assets to support the management of coastal hazards when assets are

replaced;

• Use of the existing flood policy as an interim measure to regulate inundation risks due to periodic ocean

events for future development and redevelopment of existing properties;

• Community Education in the format of ongoing updates to community regarding occurrence of climate

change, particularly sea level rise; and

• LEP Review and Rezoning to ensure that vacant land is not developed inappropriately particularly

where land that is known to be at risk from inundation.

In addition to the management options outlined above, the estuary inundation risk assessment may be used

to identify ecological communities that require priority Habitat Management and Rehabilitation. High Value

Natural Assets in the riparian corridor, floodplain and estuarine reaches of the Bellinger and Kalang River

estuaries are most at risk from rising sea levels. Given their limited distribution in a largely cleared

agricultural setting, and the poor condition of the riparian vegetation, these communities may require

management intervention to improve their resilience to increased inundation and in the case of tidal

wetlands, assist with habitat transition.

It is recommended that Council initially focus actions to address sea level rise within the extreme to high risk

locations and riparian reaches. Accordingly, eight sites are identified for ongoing monitoring of geomorphic

response and ecological community change, with site selection based on accessibility and the presence of

High Value Natural Assets likely to be impacted by sea level rise. Given the timeframes over which projected

sea level rise impacts may occur (2050 onwards), and the complicated interactions involved, Council will be

required to develop ongoing adaptive strategies to assess and manage sea level rise impacts. This will

require regular monitoring to map the distribution and condition of coastal habitats in association with any

observations of sea level rise.

Conclusion

Climate change and sea level rise have the ability to impact private and public land and assets within the

Bellingen LGA. The study has updated and made use of existing (and newly developed) computer models to

calculate tidal inundation in the main river estuary and Intermittently Closed and Open Lakes and Lagoons

(ICOLLs) present in the LGA. The study has determined the estuarine and coastal inundation extents for a

range of design ocean events and four epochs and associated mean sea levels, and identifies those areas

within the LGA that are likely to be impacted (negatively or otherwise) by sea level rise.

There are areas within the Bellinger-Kalang Estuary that may be impacted by more frequent tidal inundation

(exacerbated by sea level rise) including farmland and unsettled low-lying floodplain areas around Mylestom,

Repton and Fernmount. The Urunga Golf course and adjacent riverfront properties as well as some rural

properties located on Newry Island may also be impacted more frequently with sea level rise. Other areas

that are currently not impacted by tidal inundation but may begin to experience infrequent (i.e. 20-year and

100-year ARI events) include the broad floodplain area between Mylestom and Raleigh, and to the northwest

of Repton and Raleigh, low-lying areas to the west of Yellow Rock Road and to the east of the Pacific

Highway. Several rural, residential and primary production properties around the townships of Raleigh,

Bellingen Shire Estuary Inundation Mapping v Executive Summary


Mylestom, Repton and Fernmount, and numerous rural, residential properties situated on Newry Island may

be affected. Likewise, properties in the Urunga Industrial precinct, near the Urunga Golf Course / tennis

courts and waterfront properties in the immediate vicinity of Urunga Lagoon may also be affected.

Due to the steep topography surrounding Dalhousie Creek and Oyster Creek ICOLLs, inundation extents are

largely confined to the main waterway and adjacent low-lying intertidal area. Private properties and other

infrastructure are not expected to experience any significant inundation during infrequent tidal inundation

events (i.e. with 20-year and 100-year ARIs) even with 1.4 metres of sea level rise.

In addition to properties and infrastructure, the study area also supports a range of High Value Natural

Assets, some of which are at risk from sea level rise. Based on the sea level rise projections adopted, it is

anticipated there may be increased inundation and saline intrusion into Coastal Saltmarsh and Swamp Oak

Forest communities in the lower and middle estuarine reaches. This may result in landward retreat of those

communities if habitat conditions are suitable as well as the expansion of mangroves landward and further

upstream with the tidal front. Potential inundation of floodplain wetland habitat is also anticipated for all

estuary reaches.

Provided conditions are suitable for colonisation, estuarine wetland habitats are expected to migrate

landward in response to a shift in the tidal planes. Some habitats, particularly Coastal Saltmarsh, are prone

to coastal squeeze which may prevent landward migration as sea levels rise. This is particularly evident in

the lower reaches of the Kalang River where existing Coastal Saltmarsh communities abut residential

development including roads. Due to natural migration, low-lying, flat areas above the tidal range, particularly

those that lie adjacent to existing vulnerable habitats, may become increasingly important to protect and

restore as potential areas for future habitat migration. This includes agricultural lands which have been

previously cleared. Priority areas for protection should also be located along tributaries and creeks. It is

therefore recommended that Council considers management measures (e.g. monitoring, weed control,

revegetation, water quality protection, fire management) that provide buffering, connectivity and migration of

vulnerable habitats, particularly Freshwater Wetlands, Coastal Saltmarsh, Swamp Oak Forest, Swamp

Sclerophyll Forest, Lowland Rainforest and riparian vegetation.

Bellingen Shire Estuary Inundation Mapping vi Glossary of Terms


Glossary of Terms

100-year event An event that occurs on average once every 100 years. Also known as a 1% AEP event. See annual exceedance probability (AEP) and average recurrence interval (ARI).

20-year event An event that occurs on average once every 20 years. Also known as a

5% AEP event. See annual exceedance probability (AEP) and average recurrence interval (ARI).

Annual Exceedance Probability AEP (measured as a percentage) is a term used to describe the size of an

event. AEP is the long term probability between events of a certain magnitude. For example, a 1% AEP event is one that has a 1% probability of occurring in any given year. The AEP is closely related to the ARI.

Australian Height Datum A common national plane of level approximately equivalent to the height

above sea level. All water levels presented in this report have been provided in metres AHD.

Average Recurrence Interval ARI (measured in years) is a term used to describe event size. It is a

means of describing how likely an event is to occur in a given year. For example, a 100-year ARI event is one that occurs or is exceeded on average once every 100 years.

Average Daily Flowrate The value (which can also be expressed in m3/s) determined from

measured or modelled daily flows (typically expressed in ML/day). It represents the average flow rate over a 24 hour period and is different to peak or instantaneous daily flow.

Bathtub inundation Simplified mapping procedure used to approximate the extent of

inundation caused by increase water level in small open coastal waterbodies. Bathtub modelling delineates inundation extents using water elevation level overlaid on ground elevation. The modelling approach assumes that there is no water level gradient across the waterbody, i.e. the waterbody is essentially a ‘bathtub’ that fills with water. Also referred to as the ‘bucket fill' method.

Digital Elevation Model A digital representation of ground surface topography or terrain. Also

known as a Digital Terrain Model (DTM).

TUFLOW-FV Two and three-dimensional hydrodynamic model developed by BMT

WBM which is suitable for predicting the velocity, temperature and salinity distribution in natural water bodies subjected to external environmental forcing such as wind stress, surface heating or cooling.

Percentage Exceedance The value of a variable above which a certain percent of observations fall.

The 20% exceedance is the value (or score) below which 80 percent of the observations may be found. That is, only 20% of the observations exceed the value.

Bellingen Shire Estuary Inundation Mapping vii Glossary of Terms


Peak Flowrate The highest discharge (typically expressed in m3/s) found in a river

channel in response to a particular rainfall event. The peak flow corresponds to the point of the hydrograph that has the highest flow.

Practical Salinity Units Ocean salinity is generally defined as the salt concentration in sea water.

It is measured in unit of PSU (Practical Salinity Unit), which is a unit based on the properties of sea water conductivity. It is equivalent to parts per thousand or to g/kg.

Flood Level The height of the flood described either as a depth of water above a

particular location (e.g. 1 metre above a floor, yard or road) or as a depth of water related to a standard level such as Australian Height Datum (e.g. flood level was 7.8 m AHD). Terms also used include flood stage and water level.

Light Detection and Ranging LiDAR is an optical remote sensing technology that measures properties

of scattered light to find range / distance and can be used to measure surface elevations relative to a known datum.

Mean High Water MHW is the average of all high waters observed over a sufficiently long

period of time. Mean High Water Spring MHWS is the average of all high water observations at the time of spring

tide over a sufficiently long period of time.

Mean Higher High Water Solstice Spring MHHWSS (also known as King tides) are higher high waters that occur

around July and December. The average of all higher high waters observed over a sufficiently long period of time.

Mean Sea Level MSL is the average limit of tides and is calculated as the arithmetic mean

of hourly heights of the sea at the tidal station observed over a sufficiently period of time.

Percentile The value of a variable below which a certain percent of observations fall.

The 20 percentile is the value (or score) below which 20 percent of the observations may be found.

Sea Level Rise SLR is the long-term increase to mean sea level.

Source for Catchments An integrated (whole of catchment) model developed by eWater (publicly

owned not-for-profit organisation).

TUFLOW One-dimensional (1D) and two-dimensional (2D) flood and tide simulation

software developed by BMT WBM. It simulates the complex

hydrodynamics of floods and tides using the full 1D St Venant equations

and the full 2D free-surface shallow water equations.

Bellingen Shire Estuary Inundation Mapping viii Contents


Contents

Executive Summary i

Glossary of Terms vi

1 Introduction 1

2 Background Information 2

2.1 Description of Estuaries in Study Area 2

2.2 Previous Local Studies 2

2.2.1 Flood Studies 2

2.2.2 Estuary Studies 7

2.2.2.1 Estuary Process Study 7

2.2.2.2 Estuary Management Study and Plan 9

2.2.3 Other Relevant Studies 10

2.2.3.1 Coastal Vegetation Mapping 10

2.2.3.2 Health Plans for the Bellinger and Kalang Rivers 11

2.2.3.3 Bellinger Estuary Action Plan Reach Plan 12

2.2.3.4 Bellinger and Kalang Rivers Estuary Action Plan Stage 2 13

2.2.3.5 Bellinger-Kalang Rivers Ecohealth Project 13

2.2.3.6 Bellinger and Kalang River Estuaries Erosion Study 13

2.2.3.7 Bellingen Council Climate Change Risk Assessment 14

2.2.3.8 Bellingen Climate Change Adaptation Strategy 15

2.3 Relevant Research into Estuarine Sea Level Rise Impacts 15

2.3.1.1 Coastal saltmarsh vulnerability to climate change in SE Australia 15

2.3.1.2 Predicting the response of coastal wetlands of south eastern Australia to Sea Level Rise 16

2.3.1.3 Derwent Saltmarsh Response to Sea Level Rise 17

2.3.1.4 Estuary Adaptation to Climate Change 17

2.3.1.5 Anticipated Response Coastal Lagoons to Sea Level Rise 18

3 Estuary Inundation Modelling 20

3.1 Bellinger and Kalang River 20

3.1.1 Description and Review of Existing Flood Model 20

3.1.2 Required Updates to Flood Model 22

3.1.3 Development of Tidal Boundary Conditions 24

3.1.4 Tidal Inundation Model Results and Extents 28

3.1.5 Comparison of Tidal Inundation to Fluvial Flooding 28

3.2 Dalhousie and Oyster Creeks 35

Bellingen Shire Estuary Inundation Mapping ix Contents


3.2.1 Background and Key Processes 35

3.2.2 Determination of ICOLL Design Water Levels 35

3.2.3 Determination of ICOLL Design Flood Extents 36

4 Estuary Inundation Risk Assessment 39

4.1 Application of a Risk-Based Framework 39

4.2 Likelihood of Estuary Inundation 41

4.2.1 Likelihood Scale 41

4.2.2 Likelihood of Coastal Inundation 42

4.3 Consequence of Estuary Inundation 44

4.3.1 Consequence Scale 44

4.3.2 Register of Public and Private Assets Potentially Affected 44

4.4 Analysis of the Level of Risk 47

4.5 Estuary Inundation Risks Register 48

4.6 Triggers for Implementation 53

5 Estuary Ecological Modelling 55

5.1 Development of Hydrological Inputs 55

5.1.1 The Source Modelling Framework 55

5.1.2 Model setup 56

5.1.2.1 Overview 56

5.1.2.2 Catchment delineation and model extents 56

5.1.2.3 Functional units 57

5.1.2.4 Rainfall-runoff model 61

5.1.2.5 Meteorological data 61

5.1.2.6 Catchment parameters 63

5.1.3 Estimation of daily Runoff Volume 67

5.1.4 Selection of a Representative Inflow Timeseries 69

5.2 Development of the Estuary Model 72

5.2.1 Scope and Objectives 72

5.2.2 Model Selection 72

5.2.3 Model Geometry and Extent 73

5.2.4 Bathymetry 73

5.2.5 Model Configuration 73

5.2.6 Boundary Conditions 76

5.2.7 Long-term Estuary Modelling Scenarios 76

5.3 Estuary Modelling Results 77

5.3.1 Long-section Profiles 77

5.3.2 Cumulative Frequency Curves 84

Bellingen Shire Estuary Inundation Mapping x Contents


6 Interpretation and Risk Based Assessment of the Eco logical Impacts 87

6.1 Overview 87

6.2 Methodology 87

6.2.1 Study Area 87

6.2.2 Mapping of High Value Natural Assets 87

6.2.3 Biodiversity Consequences of SLR 90

6.2.4 Risk Assessment 90

6.2.5 Monitoring Sites 90

6.2.6 Assumptions and Limitations 90

6.3 Habitats and Landform of the Study Area 91

6.3.1 The Bellinger River - Upper Estuary 91

6.3.2 The Bellinger River - Mid Estuary 91

6.3.3 The Bellinger River - Lower Estuary 92

6.3.4 The Kalang River - Upper Estuary 92

6.3.5 The Kalang River Mid-Estuary 92

6.3.6 The Kalang River - Lower Estuary 92

6.3.7 The Kalang River Marine Tidal Delta and Urunga Lagoon 93

6.4 High Value Natural Assets 93

6.4.1 Seagrass 94

6.4.2 Mangroves 94

6.4.3 Coastal Saltmarsh 94

6.4.4 Swamp Oak Forest 95

6.4.5 Freshwater Wetlands 95

6.4.6 Swamp Sclerophyll Forest 95

6.4.7 Rainforests 96

6.4.8 Subtropical Coastal Floodplain Forest 96

6.4.9 Themeda Grassland on Seacliffs and Coastal Headlands 96

6.4.10 Riparian Corridor 97

6.4.11 Groundwater Dependant Ecosystems 97

6.4.12 State Environmental Planning Policies 98

6.5 Biodiversity Consequences of Sea Level Rise 101

6.5.1 Broad SLR Ecological Impacts 101

6.5.1.1 Seagrass 102

6.5.1.2 Mangroves 102

6.5.1.3 Coastal Saltmarsh 104

6.5.1.4 Swamp Oak Forest 105

6.5.1.5 Floodplain Habitats 105

Bellingen Shire Estuary Inundation Mapping xi Contents


6.5.1.6 Riparian Corridor 106

6.5.1.7 Groundwater Dependant Ecosystems 106

6.5.1.8 Beaches 106

6.5.1.9 Threatened Species 107

6.6 Assessment of Risk 107

7 Summary and Discussion 116

7.1 SLR and Changed Frequency of Inundation 116

7.2 Tidal Inundation 116

7.2.1 Bellinger River 117

7.2.2 Kalang River 118

7.2.3 Dalhousie Creek and Oyster Creek 119

7.3 Limitations of Inundation Mapping and Modelling 119

7.4 Suggested Provisions for Reviewing and Updating SLR Benchmarks 120

7.4.1 Independence of Mapping from Changes to Projected Rates of SLR 121

7.5 Sea Level Rise Mitigation Options 122

7.5.1 Estuary Inundation 122

7.5.2 High Value Natural Assets 125

7.5.2.1 Tidal/Near-Tidal Wetlands 125

7.5.2.2 Riparian Corridor 125

7.5.2.3 Floodplain Habitats 126

7.5.2.4 Littoral Rainforest 126

7.6 Proposed Monitoring Sites 127

8 Conclusions 128

8.1 Estuary Inundation 128

8.2 Ecological Impacts 129

9 References 131

Appendix A Description of Wave Setup A-1

Appendix B Mapping Compendium of Estuary Inundation B-1

Appendix C Asset Risk Register C-2

Appendix D Threatened Species Records D-3

List of Figures

Figure 2-1 Bellingen LGA Coastline and Estuaries 3

Figure 3-1 Tuflow Model Setup 23

Figure 3-2 Design Spring Tides 25

Bellingen Shire Estuary Inundation Mapping xii Contents


Figure 3-3 Design King Tides 26

Figure 3-4 Design Tides for 20 and 100yr ARI Events 27

Figure 3-5 100-year Design Tides 27

Figure 3-6 Reported Peak Water Level Locations and Long Section Profiles 29

Figure 3-7 Bellinger River Peak Water Level Long Section (Design Spring Tides) 31

Figure 3-8 Bellinger River Peak Water Level Long Section (Design King Tides) 31

Figure 3-9 Bellinger River Peak Water Level Long Section (Design 20-year ARI Tides) 32

Figure 3-10 Bellinger River Peak Water Level Long Section (Design 100-year ARI Tides) 32

Figure 3-11 Kalang River Peak Water Level Long Section (Design Spring Tides) 33

Figure 3-12 Kalang River Peak Water Level Long Section (Design King Tides) 33

Figure 3-13 Kalang River Peak Water Level Long Section (Design 20-year ARI Tides) 34

Figure 3-14 Kalang River Peak Water Level Long Section (Design 100-year ARI Tides) 34

Figure 3-15 Adopted Design ICOLL Water Level Exceedance Curves 37

Figure 4-1 Risk Management Framework (ISO 31000:2009) adapted to Coastal Zone Management 40

Figure 4-2 Summary of Estuary Inundation Risk for the Immediate Timeframe 50

Figure 4-3 Summary of Estuary Inundation Risk for the 2050 Timeframe 51

Figure 4-4 Summary of Estuary Inundation Risk for the 2100 Timeframe 52

Figure 4-5 Continuum Model for Climate Change Adaption Action 53

Figure 5-1 Subcatchment Delineation 58

Figure 5-2 Functional Units Used by the Catchment Model 60

Figure 5-3 Catchment Average Rainfall used by the Catchment Model 62

Figure 5-4 Catchment Average APET used by the Catchment Model 62

Figure 5-5 Daily Rainfall Data (August 2007 – December 2012) 63

Figure 5-6 Daily Streamflow Data (August 2007 – December 2012) 64

Figure 5-7 Calibrated Daily Runoff Volume (modelled vs observed) 65

Figure 5-8 Timeseries of Modelled and Observed Runoff Volume 66

Figure 5-9 Calibrated Flow Duration Curve (2007 – 2012) 66

Figure 5-10 Timeseries of Daily Runoff Volume (1900 – 2012) 68

Figure 5-11 Box and Whisker Plot of Monthly Modelled Flow for the Bellinger River Sub-catchment 69

Figure 5-12 Flow Duration Curve for Bellinger River Sub-catchment (1900-2012) 70

Figure 5-13 Timeseries of Major Inflows to the Estuary (Jan 2005 to Dec 2005) 71

Figure 5-14 TUFLOW-FV Model Mesh and Bathymetry 74

Figure 5-15 TUFLOW-FV Manning's n Distribution 75

Figure 5-16 Long-term Estuary Modelling Reporting Locations and Long Section Profiles 79

Bellingen Shire Estuary Inundation Mapping xiii Contents


Figure 5-17 Long Section Profiles of Water Level for the Bellinger River 80

Figure 5-18 Long Section Profiles of Salinity for the Bellinger River 81

Figure 5-19 Long Section Profiles of Water Level for the Kalang River 82

Figure 5-20 Long Section Profiles of Salinity for the Kalang River 83

Figure 5-21 Cumulative Frequency Curves (Water Depth) 85

Figure 5-22 Cumulative Frequency Curves (Salinity) 86

Figure 6-1 High Value Natural Assets of the Bellinger and Kalang Rivers, Floodplains and Estuaries 88

Figure 6-2 High Ecological Values GDE’s Bellinger-Nambucca Coastal Sands 99

Figure 6-3 High Ecological Values GDE’s Coastal Bellinger Alluvial 100

Figure 6-4 High Ecological Values GDE’s Coastal Kalang Alluvial 100

Figure 6-5 Predicted High Value Natural Asset SLR Impacts 103

List of Tables

Table 2-1 Peak Ocean Levels (from WMA, 2012) 6

Table 2-2 Design Flood Levels at Key Locations (from WMA, 2012) 6

Table 2-3 Modelled Climate Change Results (1% AEP) (from WMA, 2012) 7

Table 3-1 Peak Offshore Ocean Levels Adopted for Bellinger-Kalang River Estuary 24

Table 3-2 Peak Offshore Tide Levels for Five SLR Scenarios 26

Table 3-3 Summary of Peak Tidal Water Levels (m AHD) for Bellinger and Kalang Rivers 30

Table 3-4 Peak Ocean Levels for Dalhousie and Oyster Creeks 37

Table 3-5 ICOLL Peak Inundation Level for five SLR Scenarios 38

Table 4-1 Risk Likelihood / Probability for Coastal Hazards 42

Table 4-2 Timeframes for Coastal Planning 42

Table 4-3 Estuary Inundation Likelihood Summary 43

Table 4-4 Consequence Scale for Estuary Inundation 45

Table 4-5 Updated Ecological Community Consequence Ratings 46

Table 4-6 Consequences Ascribed to Assets in the Study Area 46

Table 4-7 Risk Matrix for Estuary Inundation 48

Table 5-1 Major Sub-catchment Details 56

Table 5-2 Sub-catchment Properties 59

Table 5-3 Summary of Meteorological Data 61

Table 5-4 SIMHYD Rainfall-Runoff Parameters for Bellinger River Sub-catchment 64

Bellingen Shire Estuary Inundation Mapping xiv Contents


Table 5-5 Additional SIMHYD Rainfall-Runoff Parameters for Lower Estuary Sub-catchments 67

Table 5-6 Long-term Estuary Salinity Modelling Scenarios 76

Table 5-7 Summary of Modelled Salinity Profiles (Median Salinity) 77

Table 5-8 Summary of Cumulative Frequency Results 84

Table 6-1 High value natural asset types and data sources 89

Table 6-2 Sea Level Rise Risk Assessment and Mitigation Options for High Value Natural Assets 109

Table 7-1 Adopted Ocean Levels for Bellinger-Kalang Estuary and Coastline 116

Table 7-2 Peak Tide Level at Major Bridge Crossings 117

Table 7-3 Recommended Options for Managing Estuary Inundation Hazard 122

Table 7-4 Habitat Response to SLR Monitoring Sites 127

Bellingen Shire Estuary Inundation Mapping 1 Introduction


1 Introduction

Climate change and sea level rise (SLR) have the potential to impact private and public land and

assets within the Bellingen Shire Local Government Area (LGA) as well as other coastal areas

around NSW and Australia. BMT WBM was commissioned by Bellingen Shire Council (BSC) to

systematically and comprehensively identify the extent of SLR risks facing the BSC LGA, by

determining the estuarine inundation depths and extents and the physical and ecological assets at

risk.

The study investigated a range of SLR scenarios including mean sea levels (MSL) of 0.0, 0.4, 0.7,

0.9 and 1.4 m AHD. These levels are based on the previous NSW Government planning

benchmarks which are a projected rise in sea level (relative to the 1990 mean sea level) of 0.4

metres by 2050 and 0.9 metres by 2100 (DECCW, 2009). It is important to note that due to the

inherent difficulty in forecasting actual rates of sea level rise (SLR) the mapping in this study shows

the impact of 0.0, 0.4, 0.9 and 1.4 metres of SLR but does not specify the timing of these changes

to mean sea level.

For each SLR scenario, four design events were considered, including:

• Mean High Water Spring;

• Highest High Water Spring Solstices (i.e. approx. King Tide);

• 20-year Average Recurrence Interval (5% AEP); and

• 100-year Average Recurrence Interval (1% AEP).

Inundation extents for the Bellinger and Kalang Rivers were determined using an existing flood

model (TUFLOW) for each combination of design event and SLR scenario. An assessment of tidal

inundation risk for Dalhousie and Oyster Creek lagoons was undertaken using a bath-tub approach

and design conditions appropriately derived for their location based on available water level

records for other similar waterbodies. The modelled design flood levels and inundation extents

were used to map areas of current and future tidal inundation and also to assess the risk to

infrastructure (built environment) assets.

To determine the influence of SLR on ecological assets within the BSC, a 12 month simulation of

estuary conditions (water levels and salinity) was undertaking using a flexible mesh (TUFLOW-FV)

estuary model. The 12 month simulation used appropriate hydrological inputs (calculated using a

catchment model (developed as part of the study) and investigated MSL conditions of 0.0, 0.4, 0.9

and 1.4 m AHD. Changes to the duration and frequency of inundation and also to the salinity

regime were then used to infer potential ecological change along the estuarine regions of BSC.

The study also involved a site visit to undertake ‘ground-truthing’ of infrastructure and ecological

assets and risks, and also provides suggested potential mitigation options to reduce the level of

future risk due to SLR.

Bellingen Shire Estuary Inundation Mapping 2 Background Information


2 Background Information

2.1 Description of Estuaries in Study Area The Bellingen Shire Local Government Area (LGA) is located on the NSW Mid North Coast and

includes some 15 km of coastline extending from Oyster Creek in the south to Tuckers Rocks in

the north.

Three notable coastal entrances are situated along the Bellingen coastline, namely Oyster Creek

and Dalhousie Creek (which are small creeks intermittently open to the ocean) and the larger

Bellinger / Kalang River with its partially trained entrance at Urunga (see Figure 2-1).

The floodplains of the Kalang and Bellinger Rivers between Urunga and Mylestom are low-lying

and subject to potential inundation impacts of Climate Change and SLR. The impact to both private

and public land as well as assets within the BSC LGA (if realised) is significant.

2.2 Previous Local Studies A review of past local studies has been undertaken to ensure that recent relevant information is

included in the current SLR study. A brief summary of local studies and their relevance to the

current SLR study is provided in the following sections.

2.2.1 Flood Studies

The most recent, comprehensive and up-to-date flood study for the Bellinger and Kalang Rivers is

WMA (2012). This report was produced by WMA Water for the Roads and Maritime Services

(RMS). The objective of the study was to define the existing flood behaviour within the Lower

Bellinger and Kalang Rivers to assist with:

• The design of major river crossings for the Warrell Creek to Urunga Pacific Highway upgrade

project; and

• To be extended into a flood study under the NSW Flood Policy.

The study area was defined to include those areas between the river entrance at Urunga

(downstream) to upstream extents on the Bellinger River at Bellingen Bridge (Lavenders Bridge)

and approximately 2.5 km past the Brierfield Bridge on the Kalang River.

The flood study report details the investigations, results and findings of the hydraulic modelling

study undertaken for the Bellinger and Kalang Rivers. The key elements of that report include:

• a summary of available data;

• hydraulic model development;

• calibration of the hydraulic model; and

• definition of the design flood behaviour through the analysis and interpretation of model results.



Figure 2-1 Bellingen LGA Coastline and Estuaries



The WMA (2012) report provides a brief overview of a number of previous flood related studies,

which have generally been superseded by the most recent hydraulic study including:

• New South Wales Coastal Rivers Floodplain Management Studies Bellinger Valley (Cameron

McNamara, December 1980);

• Proposed Industrial Area, Urunga NSW (Outline Planning Consultants, May 1984);

• Bellinger River May 1980 Flood Report (PWD, 1981);

• Bellinger River Flood History 1843-1979 (PWD, 1980);

• Lower Bellinger River Flood Study (PWD, 1991);

• Lower Bellinger River Flood Study, Location of Flood Marks Engineering Survey Brief (Cameron

McNamara, 1991);

• Lower Bellinger River Flood Study Compendium of Data (PWD, 1991);

• Bellinger and Kalang River’s Floods of February and March 2001 (Bruce Fidge and Associates,

2003);

• Floodplain Risk Management Study Stage 2 – An Assessment of Floodplain Management

Options and Strategies (Bellingen Shire Council, April 2002);

• Upper Kalang River Flood Assessment, (Bellingen Shire Council, December 2006);

• South Arm Road Flood Study (Final) (DeGroot and Benson Pty Ltd, June 2000);

• Upper Bellinger River Flood Assessment (Bellingen Shire Council, 2006);

• Newry Island Flood Study Draft (WMAwater, 2008);

• Warrell Creek to Urunga Upgrade Environmental Assessment (RTA, 2010);

• Review of Bellinger, Kalang and Nambucca Rivers Catchment Hydrology (WMAwater, 2011);

• Kalang River – 2009 Flood Event (WMAwater, 2011); and

• Bellinger and Kalang Rivers Flood Event of 31 March 2009 Collection and Collation of Flood

Data (Enginuity Design, 2010).

The Bellinger and Kalang River valleys have a long history of flooding. Flood records for Bellingen

date back to the 1840’s and there have been 26 floods on the Bellinger River the greatest of which

has produced flood peaks of above 8.0 m AHD at the Bellingen Bridge. More recent flood events

for which significant data are available for calibration and validation purposes occurred in 1974,

1977, 2001 and 2009.

The report indicates that there is sufficient data available for calibration and validation purposes

including water level gauges at Newry Island, Urunga, Repton and Bellinger Bridge as well as a

range of surveyed peak flood levels throughout the study region.

Modelling Approach

A hydrologic (WBNM) model was established for each catchment to determine inflows into the

hydrodynamic flood model. A combined one and two dimensional hydrodynamic (TUFLOW) model



was used to define the flood behaviour using ALS, hydrosurvey and other flood control details (e.g.

culverts and levees).

The TUFLOW models were calibrated and verified to a range of historical events including 1974,

1977, 2001 and 2009. The calibrated hydraulic models were then used to assess the flood levels

and hydraulic flood hazard for the 5-year ARI and the 10%, 2%, 1%, 0.5%, 0.2%, 0.05% Annual

Exceedance Probability (AEP) and Probable Maximum Flood (PMF) design events.

The TUFLOW flood model consisted of a 15 metre by 15 metre grid defining the channel and

overbank floodplain area for the Bellinger River, lower Kalang River and its tributaries. The upper

reaches of the Kalang River were defined by a combined one and two dimensional model, with the

one dimensional network defining the main channel and the two dimensional model domain

defining the floodplain. The flood model which has been utilised for this study is described in more

detail in Section 3.1.

Model Calibration and Validation

The 1974 and 1977 events were used for calibration of the hydraulic model. The modelled flood

levels for the 1974 event were generally within 0.4 metres of the observed values, with a tendency

to over-predict flood levels in the upper reaches and under predict them in the lower portion of the

river. The modelled flood levels for the 1977 event were generally within 0.1 metres of the

observed levels except for the lower reaches where the adopted downstream boundary is

uncertain.

The 2001 and March/April 2009 events were used for model validation. For the 2001 event, the

model calibrated well with modelled levels generally within 0.2 metres of the observed flood levels.

For the March/April 2009 event, a poor calibration was achieved in the Upper Kalang River,

however, for the remainder of the model area a good model calibration was achieved. On the

Bellinger River, the magnitude of the event is between a 10% and 2% AEP event, while on the

Kalang River the event was even larger (between 2% and 0.5% AEP).

Adopted Design Boundary Conditions

Inflows and boundary conditions for the TUFLOW model consist of a number of time-varying flow

hydrographs developed using the WBNM catchment model and Bureau of Meteorology (BoM)

design Intensity-Frequency-Duration (IFD) rainfall data. At the downstream boundary of the flood

model, a tailwater level defining the river entrance was used. The tailwater conditions (as

presented Table 2-1) were based on recorded tide levels at Coffs Harbour, experience on nearby

catchments and OEH guidelines.



Table 2-1 Peak Ocean Levels (from WMA, 2012)

Design Event Peak Level (m AHD)

5-year ARI 1.45

10% AEP 1.64

2% AEP 2.0

1% AEP 2.1

Modelled Design Event Results

Maps of peak flood levels and velocities for the 5-year ARI, 10, 2, 1, 0.5, 0.2 and 0.05 % AEP and

Probable Maximum Flood (PMF) design events were presented in the report and tabulated as

reproduced below in Table 2-2.

Table 2-2 Design Flood Levels at Key Locations (fro m WMA, 2012)

Modelled Climate Change Results

The study also investigated the impacts of climate change including:

• increases in peak rainfall and storm volume of 10%, 20% and 30%; and

• an increase to MSL (sea level rise) of 0.4 metres and 0.9 metres.

Table 2-3 presents the results of the impacts of climate change for the 1% AEP event. The climate

change results show that away from the immediate mouth area (i.e. near the river confluence) the

impacts of increases in MSL due to SLR are less than 11 cm and in most places less than 4 cm.



Table 2-3 Modelled Climate Change Results (1% AEP) (from WMA, 2012)

2.2.2 Estuary Studies

2.2.2.1 Estuary Process Study

An Estuary Process Study of the Bellinger and Kalang River System was prepared in 2003 on

behalf of the Bellingen Shire Council and the Department of Infrastructure, Planning and Natural

Resources by Lawson & Treloar (2003).

The model study included the development of both a hydrologic (MUSIC) and hydraulic (DELFT3D)

model. A review of the DELFT3D model shows that it was of the estuary channel only and hence

was not suitable for the current SLR study.

The catchment model was calibrated for the period 1 January 1996 to 31 December 1996

achieving less than 10% difference between annual recorded and modelled flow volumes at Thora.

However, validation of the model for the period 1 January 1995 to 31 December 1995 achieved a

greater difference (30%) between annual recorded and modelled flow volumes at that same

location.

The main findings of that investigation are summarised under the following headings.

Estuary Type and Features

• The estuary is classified as being a wave dominated delta. The estuary has evolved over

geological time with the primary forcing factors being sea level change, riverine flows, episodic

flooding and wave climate;



• Since European settlement, the estuary has further changed with primary forcing factors being

human intervention with the partial training of the entrance and the river channels and the

forestry industry occurring in the upper catchment;

• The geomorphology of the system is one of wide low gradient rivers on coastal plains with

irregular meanders. The river channel is up to 60 metres wide at some locations, but with a low

channel slope in the estuarine reaches; and

• The salinity of the rivers varies with the limit of saline penetration being about 24 km upstream

of the entrance on the Bellinger River and 20 km upstream of the entrance in the Kalang River.

The salinity structure is generally well mixed, but a salt wedge can form periodically following a

period of fresh water flow.

Catchment and Floodplain Processes

The study catchment is largely forested or national park with small pockets of urban development

located within. In the lower estuary, the floodplain is largely used for agricultural purposes with

some industry (e.g. dairy farming and a former antimony processing site).

Hydrodynamics

Hydraulic processes within the Bellinger and Kalang Rivers are dominated by flood and ebb tidal

movements as well as freshwater inflows from the upper catchments. The hydrodynamics of the

system are also controlled by the partially trained entrance and the half-tide training walls

constructed in the early 1900’s, which restrict tidal flow to some areas (most notably Urunga

Lagoon).

Water Quality Processes

Water quality processes within the rivers are also dominated by tidal inflows and outflows, as well

as inputs within the catchment from both diffuse and point sources. The lower portions of the rivers

are well flushed by the astronomical tides (the lower reaches of around 8 km length), whilst the

upper reaches of the estuary rely on freshwater inflows for periodic flushing and to maintain good

water quality.

The water quality of Urunga Lagoon has the longest and most consistent data record. Available

data indicate that the ambient quality of the water in Urunga Lagoon is generally within ANZECC

(2000) guidelines. Nonetheless, the community reports an alternate view of water quality of the

Lagoon. Data indicate that the water quality in wet weather conditions appears to be an issue, but

certainly within the range of values expected for an estuarine system with urban runoff contribution

(Lawson & Treloar, 2003).

Sedimentary Processes

Sedimentary processes within the estuary are dominated by marine sand intrusion in the lower

portions of both the Bellinger and Kalang Rivers from the open coastal zone, whilst the upper

reaches of the estuary are dominated by fluvial sediment inputs. Marine intrusion is controlled by

the entrance training walls, which form an interruption to the littoral sand drift along the coast.

Episodic catchment flood events of small magnitude result in the transport of fluvial material down

the estuary. Larger magnitude events can result in significant bank and bed scour in the estuarine



and freshwater reaches of the river, causing deposition of fluvial materials within the estuary,

scouring of the entrance bar and deposition of sediments offshore. Limited sampling of sediment

quality undertaken during estuary processes study indicates that sediment quality is reasonable

and within the ANZECC (2000) guidelines for the estuary. Acid sulfate soils are a considerable

potential issue for the estuary, however, no data are available to indicate actual acid sulfate soil

issues and associated low pH of estuarine water, fish kills associated with low pH or metal releases

from sediments.

Flora and Fauna

The ecology of the estuary consists of a variety of flora and fauna with some threatened and

endangered species (see Appendix D for more detail). The estuary also contains a number of

SEPP14 wetlands and the catchment contains a small pocket of SEPP26 littoral rainforest. Field

mapping of seagrass and mangroves was undertaken as part of study as well.

Human Impacts

Recreational usage varies along the length of the estuary, with a variety of water-based activities,

including water skiing, fishing, sailing kayaking and swimming. The stability of riverbanks is an

ongoing issue, noticeable for over 40 years and is largely a result of human impact in the upper

reaches of the river and catchment as well as modifications to the riparian vegetation in the

estuarine areas (e.g. clearing for agriculture and cattle grazing).

Concluding Remarks

Overall, the estuary is a modified system, but appears to be functioning well, given the wide range

of uses and the human impacts throughout the catchment. The interactions amongst the processes

are complex and the ongoing recognition of these interactions through the management phase of

the estuary management process will be vital to ensure that the value of the estuary is maintained

and enhanced.

2.2.2.2 Estuary Management Study and Plan

The Estuary Management Study for the Bellinger and Kalang Rivers was completed by BMT WBM

in 2007 on behalf for the BSC. The study consisted of a broad range of components including a

detailed review of the estuary's environmental attributes, societal uses/values and existing

management frameworks (statutory and non-statutory). Arising from this review and consideration

of community and stakeholder input, issues for future management were identified. Management

objectives were developed to address these issues and with the assistance from the local

community were prioritised. The outcomes of that report form the basis for the future estuary

management plan (BMT WBM, 2007a).

The Estuary Management Plan (EMP) for the Bellinger and Kalang Rivers was completed by

BMT WBM in 2007 and adopted by BSC in May 2008. The report presents prioritised management

strategies and actions for the Bellinger and Kalang River estuary to be implemented over the next

five or more years. The main issues affecting the long-term management of the Bellinger and

Kalang River estuaries were compiled from a number of different sources and have been collated

into the table reproduced below.



Twenty four (24) management objectives were defined and prioritised. The estuary management

plan contains details of each of the objectives, suggested tasks and resources to meet the

objectives (including responsible agencies, approximate timeframes, costs and potential funding

sources). Management Objective 20 (Ensure climate change and sea level rise implications are

incorporated into Council’s planning horizon) will be partly fulfilled by completion of this SLR study.

2.2.3 Other Relevant Studies

2.2.3.1 Coastal Vegetation Mapping

The Bellingen Coastal Vegetation Mapping Project was undertaken by Flametree Ecological

Consulting on behalf of BSC in 2006. The relevant outcomes of the study include:

• Identification and mapping of vegetation communities on public land in the coastal parts of the

Bellingen LGA (the Study Area);

• Identification and mapping of Endangered Ecological Communities in the Study Area;



• Mapping of the incidence and severity of infestations of weed species at selected points in the

Study Area; and

• Mapping of vegetation condition (weed levels) over the whole of the study area.

The study area (i.e. the area mapped) consists of public land in the coastal parts of Bellingen LGA

from Tuckers Rocks to Wenonah Head. The mapping was typically restricted to between 50 and

200 metres from the coast and did not include any areas along the Bellinger / Kalang estuary

outside of the coastal fringe.

GIS output from the study have been used in the ecological risk assessment of the SLR study.

2.2.3.2 Health Plans for the Bellinger and Kalang Rivers

The Bellinger River Health Plan (BSC, 2010a) and the Kalang River Health Plan (BSC, 2010b) are

both community-driven, action-oriented plans which have been prepared in a partnership between

the NSW Department of Environment and Climate Change (DECC) and BSC.

The purpose of these two plans is to document the issues which affect river health from community

and agency perspectives and priorities, and to assess how these issues currently impact on water

quality and river health. The plans recommend actions to address issues and improve

management though best practice.

These documents are of interest to the current study in that they both identify a range of issues

(which includes sea level rise) impacting on the study area. The impacts of SLR identified by the

plans are reproduced below.

Impacts of Sea Level Rise

The impacts of rising sea level are many. There is the predicted salt water intrusion into aquifers

and estuaries, affecting coastal ecosystems, water resources and human settlements. There will be

changes in the distribution and extent of coastal wetlands, impacting upon agriculture and low lying

urban settlements. There will be changed flushing behaviour of estuaries. Coastal impacts are

likely to be shoreline recession and realignment of beaches.

The intrusion of salt water into the aquifer is of particular concern to Council because the extractive

bores that supply the towns of Bellingen and Urunga lie approximately 1 km upstream of the

current known tidal limit. In addition to this, further salt water intrusion into the estuary might affect

the utility of certain sections of the Bellinger River and Kalang River for irrigation purposes.

Whilst the global impacts of climate change are becoming increasingly clear, it is still uncertain

what the effects on local systems like the Bellinger and Kalang Rivers will be. The science required

is complicated. Coastal erosion effects will almost certainly result in increased sediment deposition

within estuaries. The impacts of this upon estuarine ecosystems will be dependent upon specific

rates of sedimentation, rates of sea level rise and elevation-dependent accommodation space for

migration of mangroves, salt marshes and seagrasses.

Sea level rise will impact on drainage and groundwater in the Bellinger-Kalang coastal floodplain.

The specific effects may be increased flood levels and duration, water logging of soils, soil

salinisation and reduced irrigation amenity of groundwater due to saline intrusion (CSIRO, 2007).



Sea level rise will also result in an upstream migration of the saltwater/freshwater interface (Newton

2008). This could be exacerbated by reductions in average freshwater flows associated with

climate change predictions. Increased acidification of estuarine waters could also result. Greater

fluctuations in the levels of groundwater could potentially increase the risk of exposure of acid

sulfate soils which, when combined with a higher proportion of rainfall falling in storm events, could

escalate the potential for delivery of acid water. In addition, higher concentrations of carbon dioxide

in the atmosphere are lowering the pH of oceanic waters. The impacts of this on shell-forming

creatures and the ecosystems they support are potentially enormous.

Planning for sea level rise is complicated by other factors. The increase in sea level will exacerbate

the effects of extreme sea level events known as storm surges. Storm surges are regular events

where storm associated low air pressure and high winds create a temporary surge in local sea

levels. Against a background of elevated sea levels, storm surges are predicted to more frequently

inundate low lying urban and agricultural areas and to more fully impact upon coastal geography as

seawater penetrates further inland and causes greater erosion.

The worldwide increase in the number of people flooded per year with a sea level rise of 1 metre is

expected to increase more than tenfold (CSIRO, 2008). Increases in severe storm events and an

extension of the tropical cyclone zone further south will result in high winds and extreme wave

events that will further erode coastlines and add to the encroachment of seawater into catchments

and urban areas. In general we are likely to see increased coastal inundation, erosion, significant

changes to estuarine ecosystems, water quality and hydrodynamics and groundwater resources.

2.2.3.3 Bellinger Estuary Action Plan Reach Plan

The Bellinger Estuary Action Plan Reach Plan (BSC, 2011) identifies key threats to the Upper-Mid

Bellinger River Estuary (Bellingen to McGeary’s Island) and makes recommendations in regards to

actions to address those threats. Recommendations are made at the reach scale and then used to

develop a Site Action Plan (SAP) for each property.

In the upper-mid estuary, episodic fluvial processes (driven by freshes and floods) tend to create

issues such as bank scour, slumping failures. Other degrading processes resulting from wave

action (wind and boat), unmanaged stock access, inappropriate land use or the

removal/suppression of riparian vegetation place ongoing pressure on the system at specific

locations.

A riparian baseline assessment of the study reach was undertaken by BSC and NRCMA staff

during late August 2010. These data were used to determine the level of intervention required and

the prospective target condition rating for the reach. Parameters collected include:

• Canopy, mid story and ground cover;

• proportion of weed infestation within the canopy, mid story and groundcover zones;

• Weed species densities;

• Data collected may also be used to determine the level of success towards the target condition

rating following intervention Areas of significant erosion;

• Stock access;



• Riparian regrowth; and

• Riparian width and suitability.

The assessment found that river bank condition in the upper-mid Bellinger River estuary is

generally moderate to poor. Geomorphic and fluvial drivers underpin the general character and

behaviour of the estuary, while more recent anthropogenic influences have resulted in accelerated

changes to the river system and surrounding environments. Landuse practices including historical

gravel extraction, riparian clearing and introduction of exotic species have resulted in a degraded

estuarine ecosystem with limited riparian stability and connectivity. Dense riparian forest that would

have covered the floodplain areas has now been all but removed.

The baseline assessment and associated bank condition data may be used to determine the level

of success towards the target condition rating following intervention, and also provide a historical

baseline of river bank condition that could be used for monitoring future SLR impacts. Land

managers are encouraged to use this Plan to guide activities being undertaken as part of routine

management, which may also be extended to include future management actions to reduce the risk

of SLR to key localities within the estuary.

2.2.3.4 Bellinger and Kalang Rivers Estuary Action Plan Stage 2

The Stage 2 Estuary Action Plan incorporates property scale rehabilitation plans on an estuary

wide scale. It builds on management objectives outlined in the existing EMP to develop estuary

wide priorities to address river health issues, control bank erosion and raise community awareness

of estuarine processes and its sensitivities. A key focus is to supplement the current EMP to

incorporate the impacts of climate change. The planning process engages and empowers

landholders to take action through establishing a set of priorities for protecting and enhancing their

riparian frontage. Additionally, the plan allows Council to prioritise future management interventions

and serves as a platform to obtain additional funding for restoration works.

2.2.3.5 Bellinger-Kalang Rivers Ecohealth Project

Bellinger-Kalang Rivers Ecohealth Project provided an assessment of river and estuarine condition

for 10 freshwater and 12 estuarine locations along the river system for a 12 month period from

October 2009 to September 2010 (Ryder, et. al., 2011). Monthly sampling at each site collected

water chemistry data including pH, conductivity and salinity, dissolved oxygen (DO), temperature,

turbidity, TN, TP, SRP and NOx. An assessment of riparian condition and macroinvertebrate

sampling was also undertaken at the 10 freshwater sites but not for the estuary sites.

The field data collected at the estuary sites may be of future use for calibration of an estuary model

and as baseline datasets to assist with future monitoring of potential ecological impacts caused by

SLR.

2.2.3.6 Bellinger and Kalang River Estuaries Erosion Study

The Telfer and Cohen (2010) erosion study was commissioned by BSC to implement a number of

objectives regarding bank erosion identified in the estuary management plan (refer Section

2.2.2.2).

Bellingen Shire Estuary Inundation Mapping 14 Backgr ound Information


The report provides information on the current processes and distribution of erosion in the two

estuaries by:

• Documenting the historical changes that have occurred in the Bellinger and Kalang estuaries

including late Quaternary estuary evolution and changes to land use and hydrological regime

over the past century;

• Identifying and describing geomorphic process zones within each estuary with a particular view

to identifying the occurrence and extent of the main depositional environments (i.e. marine-tidal,

fluvial transition and fluvial dominated), using existing information (documents, reports and

datasets made available by Bellingen Shire Council, New South Wales Department of

Environment, Climate, Change and Water), aerial photography and bathymetric data; and

• Examining the rates and magnitudes of accelerated bank erosion in key areas by analysing

historic and recent hydrographic data and photogrammetric analyses of bank erosion/channel

migration in key areas over the period 1942 to current (2014).

The report also summarises the results of the 2009 field assessment of bank condition including:

• An analysis of the current distribution of bank erosion within the Bellinger/Kalang estuaries

including the identification of areas of current accelerated change with reference to the 2009

floods;

• A description of riparian vegetation condition throughout the estuary area and an explanation of

the correlation between riparian vegetation condition and bank erosion severity; and

• A summary of the distribution and effectiveness of bank protection works and options for future

works that represent current best-practice.

The report also provides management recommendation for future management of erosion within

the two estuaries based on the findings of the study. The analysis of erosion in the Bellinger River

estuary identified twelve sites of erosion significance of which two are considered to be highest

priority for remedial action, while the analysis of erosion in the Kalang River estuary identified

sixteen sites of erosion significance, three of which are considered to require immediate attention.

2.2.3.7 Bellingen Council Climate Change Risk Assessment

The Climate Risk (2010a) report was prepared for BSC to provide information to support local

government climate change risk assessment and adaptation planning and identify a path towards

Council’s resilience to climate change as part of the Australian Government Local Adaptation

Pathway Program (LAPP).

An internal workshop undertaken as part of the study identified twenty five sites of which six were

classed as ‘very high priority’ for 2030. These were damage to roads and infrastructure from storms

and flooding; increased bushfire risks to life and property; increased price of energy from a carbon

constrained economy; threats to the sewer and water system from sea level rise; and isolation of

the community during flooding events.

Relevant chapters from the report regarding sea level rise and the impact on coastal environments

are reproduced below.



Sea Level Rise and Storm Surge

Sea level rise will not only result in direct erosion problems, but will also further the penetration of

saline water and waves inland. The short-term excursion of saline water into freshwater

environments can result in fish kills and other adverse effects on local fauna and flora populations.

With more frequent storm surge, increased coastal erosion, changing sedimentation patterns, and

disruption of estuarine environments are expected. In addition, high wave events are likely to

significantly alter the sediment patterns of estuarine areas. Beaches and estuarine areas within the

region may be washed away, or have high level of debris and pollutants washed onto them

reducing their aesthetic, natural and recreational value. Impacts on both the natural and built

environment could be significant.

Impacts on Coastal Environments

The coastal habitats within the region, including coastal wetlands, are of significant environmental

value. They provide a diversity of habitat for many aquatic and terrestrial organisms. Importantly,

the region has a number of coastal lakes and lagoons which:

“...typically have intermittently open entrances to the ocean. The lakes are unique in their

biodiversity and their ecological and physical processes. They can alternate between freshwater

and saltwater regimes. These lakes are highly susceptible to impact from climate change and

urban activities.”

Of concern for the preservation of these Intermittently Closed and Open Lake or Lagoons

(ICOLLs), changing sedimentation is highly likely to change this regime. In addition, changing sea

level is likely to inundate these bodies with salt water, increasing salinity concentration and altering

the changing freshwater and saltwater regimes. Bellingen has important estuarine environments

which may alter due to changing sediment loads.

2.2.3.8 Bellingen Climate Change Adaptation Strategy

The Climate Risk (2010b) report was prepared for BSC to provide information on climate change

adaption planning as part of the Australian Government Local Adaptation Pathway Program

(LAPP). The objective of the Adaption Plan is to provide a comprehensive strategy to develop

climate change resilience and adaptive capacity for the mid north coast councils of Nambucca,

Bellingen and Kempsey.

An action raised in the adaptation strategy is data collections (LiDAR acquisition) and undertaking

modelling to quantify the impact of SLR on infrastructure and ecological assets.

2.3 Relevant Research into Estuarine Sea Level Rise Impacts A review of relevant research into the impact of sea level rise on estuarine environments was

undertaken to guide and inform the current SLR study, which is summarised below in the following

sections.

2.3.1.1 Coastal saltmarsh vulnerability to climate change in SE Australia

The Rogers and Saintilan (2009a) paper provides information on the ecological significance of

coastal saltmarsh. Key points outlined by their study include:



• Coastal saltmarsh has been listed as an Endangered Ecological Community in New South

Wales;

• Recent research has highlighted the importance of coastal saltmarsh as a source of nutrition for

fish, a nocturnal feeding habitat for microbats, and a roosting habitat for several species of

migratory shorebirds;

• Since European colonisation, coastal saltmarsh has been reclaimed for agricultural, residential

and industrial use, and the past five decades has seen a consistent replacement of saltmarsh

by mangrove throughout SE Australia;

• A major problem in coastal wetland conservation is the lack of knowledge on ecosystem

response to sea level and the absence of planning tools for estuarine managers to incorporate

anticipated responses in planning for ecosystem protection in the future; and

• To preserve or enhance ecologically desirable habitat, planning agencies must make

appropriate zoning decisions now in anticipation of climate trends.

2.3.1.2 Predicting the response of coastal wetlands of south eastern Australia to Sea Level Rise

The Rogers & Saintilan (2009b) paper provides information on the predicted response of coastal

wetlands in NSW to SLR.

A summary of key points includes:

• Sea-level rise has been listed as a key threatening process. Over the previous five decades

moderate rates of sea-level rise have coincided with the invasion of saltmarsh by mangrove;

• It has been predicted that the capacity of a wetland to keep pace with sea-level depended on its

ability to maintain elevation though processes of vertical accretion; and

• The original assumption that march development (vertical accretion) keeps pace with sea level

rise was originally postulated in the 1850’s and has only recently been challenged.

The paper provides detail of a study as summarised below:

• Surface elevation tables (SETs) were installed in 12 coastal wetlands in Southeastern Australia

to establish elevation and accretion trajectories for comparisons with mangrove encroachment

of saltmarsh and sea-level rise;

• SETs confirmed that the elevational response of wetlands is more complex than accretion alone

and elevation changes may also be attributed to below-ground processes that alter the soil

volume such as subsidence/compaction, groundwater volume fluctuations, and below-ground

biomass changes; and

• A simple modelling approach was employed to establish a relationship between the observed

rate of mangrove encroachment of saltmarsh and relative sea-level rise, which incorporates the

eustatic component of sea-level rise and changes in the marsh elevation.



2.3.1.3 Derwent Saltmarsh Response to Sea Level Rise

The Prahalad et. al. (2009) report describes a project whose primary objective was to predict the

future extent and migration pathways of tidal wetlands in the Derwent Estuary in the event of

predicted future sea level rise. The project involved three stages including mapping of the current

extent of tidally influenced wetlands and marshes and analysis, inundation modelling due to SLR

and predicting the future extent of saltmarsh. The project was a preliminary assessment of the

future extent of saltmarshes and freshwater wetlands, and did not include any consideration of the

rates of sedimentation (vertical accretion), wind-wave climate (fetch modelling) and historical

shoreline change.

A number of relevant points extracted from the study include:

• Tidal influence is a primary driver of the development, extent and function of tidal wetlands,

especially saltmarsh;

• They are generally known to occur between the area below the mean high tide mark and the

storm tide mark, with salt spray extending this range further inland in some cases. This

hypothesis was supported by the current landward extent of the saltmarshes within the Derwent

Estuary, which, in most cases, aligned well with the greatest landward intrusion of the modelled

storm tide (i.e. the 1 in 100 year storm tide with current sea level); and

• The future landward extent of the saltmarsh can be reasonably expected to fit with the landward

intrusion boundary of the future modelled storm tide plus the projected sea level rise. A future

tidal wetland extent for the study site was determined based on the above hypothesis, and a

scenario of 110 cm sea level rise in the year 2100. It is possible that saltmarsh may not be able

to establish where ‘concrete human footprints’ exists in the form of houses, roads and other

constructed environments, and hence, the future tidal wetland extent layer should not include

those areas.

2.3.1.4 Estuary Adaptation to Climate Change

The Rogers & Woodroffe (2012) paper describes a range of predicted estuarine response to

climate change based on the geomorphic features of the estuary.

A number of relevant points from the paper include:

• An estuary is a zone where marine water and freshwater derived from catchments merge.

These waters transport sediment from the marine and terrestrial environments where they are

deposited or redistributed to other environments and these sediments provide substrate and

nutrients for the development of biota and ecosystems that are unique to estuarine

environments;

• The relationship between rates of sediment supply and rates of sea-level rise is central to

understanding the geomorphic response of estuaries to climate change. Surplus or deficits of

sediment from a shoreline or estuary over a period are regarded as the ‘sediment budget’. A

positive sediment budget occurs when sediment gained on a coastline exceeds the sediment

lost over a period, with the net result being shoreline progradation or shoreline elevation



increase; conversely, regression at the geological scale, or erosion at the event scale, is

associated with a negative sediment budget.

• Depositional environments in estuaries are artefacts of positive sediment budgets occurring

under stable sea-level conditions over the mid to late Holocene (and in some cases during the

Pleistocene). Efficient trapping of sediment and evolution towards ‘maturity’ is largely driven by

rates of sediment supply from the catchment and marine environments and the hydrodynamics

within an estuary. Hence mature estuaries exhibit a strongly positive sediment budget, with

rates of sediment supply tending towards equilibrium with sea-level rise, while immature

estuaries exhibit weakly positive sediment budgets, with sediment supply lagging behind rates

of sea-level rise. Analysis of contemporary sediment budgets provides valuable information for

quantifying the response of estuaries to projected sea-level rise in the 21st century.

• Sea-level rise acts to reverse estuary evolution and increases the areal extent of open water

and intertidal areas within estuaries, thereby creating accommodation space for the deposition

of marine sands and terrestrial colluvial deposits, muds and silts. Due to strong hydrological

links between the ocean and estuaries (and even intermittently open estuaries or ICOLLs), base

and maximum water levels within estuaries are projected to increase at rates equivalent to sea-

level rise. The geomorphic response of estuaries to sea-level rise, evident through increased

accommodation space, will vary in accordance with a number of factors including estuary

maturity, shape of the bedrock valley and estuary zonation.

• The adaptive capacity of an asset within an estuary can be guided by the natural occurrence, or

absence, of depositional shorelines within an estuary (e.g. mangrove, saltmarsh and intertidal

flats), which indicates the sediment budget of the estuary over geological timescales.

The paper applies its morphological assessment methodology to two estuaries in NSW and

highlights their likely differences of response and impacts due to SLR. The paper also provides a

summary of predicted changes to wetland vegetation at a mangrove-saltmarsh site in Minnamurra

estuary.

2.3.1.5 Anticipated Response Coastal Lagoons to Sea Level Rise

The Haines (2008) paper provides information regarding the anticipated response of coastal

lagoons to SLR.

A number of relevant points from the paper include:

• Coastal lagoons, or ICOLLs, are a common feature on the south-east coast of Australia

(particularly in NSW). Their environmental processes have evolved in response to their unique

hydrological behaviour, which is dependent on both catchment and coastal processes and

inputs. Of most significance to the structure and function of coastal lagoons is the condition of

its ocean entrance. When open, the entrance allows for regular tidal exchange and oceanic

flushing of the lagoon. When closed, however, the lagoon becomes a ‘terminal lake’ and

captures and retains 100% of all catchment inputs.

• The entrance processes of coastal lagoons, comprising the scouring or breakout stage, followed

by berm rebuilding and eventual closure, are dependent on dominant coastal processes. Long

term sea level rise is expected to have a significant impact on the entrance processes of coastal



lagoons, which will subsequently have a cascading effect on most other environmental

processes within these naturally sensitive and unique waterways.

• An increase in mean sea level will result in an upward and landward translation of ocean beach

profiles. With respect to coastal lagoons, a sea level rise will cause the entrance sand berm to

move inland and to build up to a higher level relative to local topography. The increase in berm

height is expected to match the increase in sea level rise, given that the berm is built primarily

by wave run-up processes.

• Elevated water levels within coastal lagoons, as a consequence of higher entrance berm levels,

or higher tide levels, will potentially result in a landward migration of fringing lagoon vegetation.

If vegetation communities cannot easily migrate upslope, due to obstructions or topography,

then the vegetation communities may be lost altogether.

Bellingen Shire Estuary Inundation Mapping 20 Estuary Inundation Modelling


3 Estuary Inundation Modelling

The impact of SLR on areas within the Bellingen Shire LGA has been assessed by modelling a

range of design tidal inundation events on the three estuaries located in the LGA. The existing

TUFLOW flood model of the Bellinger and Kalang River was reviewed, updated (where necessary)

and adopted for use in determining design tidal inundation levels and extents for current and future

SLR conditions. For the smaller Dalhousie Creek and Oyster Creeks ICOLLs, a bathtub approach

was used to determine design tidal inundation extents.

Details of the model review, development of design boundary conditions and inundation modelling

results is presented in the following sections.

3.1 Bellinger and Kalang River Due to the size and wide meandering channels of the Bellinger and Kalang River system, a

numerical flood model was required to determine flood levels and extents due to existing and future

(i.e. SLR) tidal inundation processes for a range of design events. The model was used to

investigate SLR scenarios including MSL of 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.

For each SLR scenario, four design events were considered, including:

• Mean High Water Spring;

• Highest High Water Spring Solstices (i.e. approx. King Tide);

• 1:20 year (5% AEP); and

• 1:100 year (1% AEP).

3.1.1 Description and Review of Existing Flood Model

BSC provided an existing TUFLOW flood model of the Bellinger and Kalang River system for use in

the SLR study. The model was developed by WMA water on behalf of Council and the Roads and

Maritime Service (RMS) to investigate the impacts of the proposed upgrade of the Pacific Highway

across the floodplain (refer to Section 2.2.1). A description and review of the existing flood model is

provided below.

Model Software Review

TUFLOW is a hydrodynamic model developed by BMT WBM that provides one-dimensional (1D)

and two-dimensional (2D) solutions of the free-surface flow equations to simulate flood and tidal

wave propagation. TUFLOW is used by over 500 organisations in 16 countries primarily for flood

modelling studies and has been commercially available since 2004 (www.tuflow.com). The

software is ideally suited to applications such as the current SLR study.

Model Extent Review

The model extents are presented in Figure 3-1 and include:

• Upstream to Bellingen Bridge (Lavenders Bridge) on the Bellinger River;

• To 2.5 km past the Brierfield Bridge on the Kalang River; and



• Downstream to the Pacific Ocean.

The modelled extents are appropriate for tidal inundation modelling and no ‘glass walling’ (caused

by a lack of floodplain definition) was observed at the model boundaries.

Model Bathymetry Review

A range of topographic information is used by the model including:

• Airborne Laser Scanning (ALS) ground levels, collected as part of the Land and Property

Management Authority’s Coastal capture program (the actual survey date is not reported but it

is sometime before January 2012);

• Hydrosurvey collected by OEH between September and November 2008 of the estuary sections

of the Bellinger River, Kalang River and Pickets Creek; and

• Culvert and structure details based on an RTA culvert database.

The model review indicates that these data sets are suitable for use in the SLR study, however, it

appears that a number of culverts under the Northern Railway and Hungry Head Road (to the west

of Urunga Lagoon) were not included in the model.

Model Mesh Review

A Digital Elevation Model (DEM) of the model mesh was generated and compared favourably to

the raw ALS and hydrosurvey data, indicating that appropriate mesh elevations have been used for

the existing topography. The selection of a 15 metre by 15 metre grid for the 2D model domain is

appropriate to represent larger channels, flow paths and topographic features. The use of model

elevation modification (referred to a ‘z-lines’) has been used appropriately to represent several sub-

grid features including the crest of the breakwaters and the crest of the Pacific Highway. 1D

channels have been used appropriately for the upper Kalang River and for Boggy Creek to better

represent the channel conveyance in areas where the 2D grid resolution is unable to adequately

represent the channel profile (refer to Figure 3-1).

A check of ‘glass-walling’ to ensure that all the floodplain had been included revealed only a small

(insignificant) reduction in floodplain width occurred on the northern extent of the model, where a

small approximately 150 metre section of a valley near Pine Creek State Forest was excluded from

the model. Given the floodplain is approximately 3 km wide in this area this minor error will have an

insignificant impact on inundation results.

Model Roughness Review

The magnitude and spatial variation of model roughness is presented in WMA (2012) and

reproduced in Figure 3-1. A review of the model roughness values adopted by the model indicated

they are suitable for use in the SLR study.

Model Structure Review

A range of structures were included in the hydraulic model. Structures in the 2D domain have been

modelled using appropriate values to represent hydraulic losses or sub grid flow constrictions. A

number of culverts have been appropriately represented as 1D elements linked into the 2D domain.



With the exception of culverts omitted under the Northern Railway and Hungry Head Road (to the

west of Urunga Lagoon) it appears that all structures have been appropriately modelled.

Model Parameter Review

All adopted parameters (i.e. turbulent mixing parameters) are within the usual range adopted for

hydrodynamic modelling of an estuary.

Tidal Calibration Review

The achieved calibration of the TUFLOW flood model is presented in WMA (2012) and summarised

in Section 2.2.1 of this report. It is important to note that the model has only been calibration to

match observed fluvial events and no specific calibration to a period of typical tides or storm surge

event has been undertaken. The time-series of observed and modelled water levels for the fluvial

calibration event presented in WMA (2012) include short periods of time prior to the flood arriving

which indicate the model is able to match the timing of observed tides. However, the model tends

to under-estimate the level of the observed tides which is likely to be due to an underestimate of

river base flow.

The lack of an appropriate tidal calibration reduces the level of certainty associated with the

prediction of absolute flood levels for the given design events. However, despite the lack of tidal

calibration, the model will be suitable for determine the relative changes to tidal inundation events

in the study area.

3.1.2 Required Updates to Flood Model

A number of minor model updates were required to improve the existing TUFLOW flood model to

increase its suitability for use in the tidal inundation assessment. Improvements to the mode

included:

• Reducing the model extent upstream of Bellingen to reduce a model instability that occurred

during low flow conditions;

• Improvement of water lines along Boggy Creek to improve the presentation of mapped output;

• Inclusion of flow paths to represent culverts under the Northern Railway and Hungry Head Road

(to the west of Urunga Lagoon). It should be noted that as no survey data were available (i.e.

dimensions and inverts of the structures), flow paths are only approximate and are provided to

ensure connectivity to all areas of potential tidal inundation are represented in the model;

• Improvement of the 1D-2D connection along the Upper Kalang to reduce a minor model

instability;

• Removal of minor catchment inflows / base flow applied to the upstream boundary of the

Bellinger River and Kalang River; and

• Adjustment of small patches of drain or beach where the elevation was below 0.9 m AHD to

remove wet cells due to the assignment of an 0.9 m AHD initial water level required for the

0.9 m SLR scenario.

It should be noted that all of these updates are minor in nature and will not greatly affect model

predictions of the WMA (2012) flood model.

Bellingen Shire Estuary Inundation Mapping 23 Estuary In undation Modelling


Figure 3-1 Tuflow Model Setup



3.1.3 Development of Tidal Boundary Conditions

The aim of the current study was to determine the estuarine inundation extent for a range of design

ocean events including the spring tide, king tide, 20-year ARI and 100-year ARI event as defined in

Table 3-1. The adopted values of peak level were agreed upon after consultation with OEH and

BSC. Peak levels for the spring and king tide are based on tidal planes analysis of Coffs Harbour

data presented in MHL (2012).

Adopted peak ocean levels for the 20-year ARI and 100-year ARI events are lower than the

DECCW (2010) guidelines which provide recommended levels for the open coast but not for deep

river entrances such as that present in the study area. Wave setup acts to increase the still water

level (SWL) at the shore line due to the conversion of the wave’s kinetic energy into potential

energy as the wave breaks in the surf zone which is further explained in Appendix A.

The adopted peak levels are 0.5 metres lower than that provided for the open coast because the

estuary mouth is partially trained on the southern side and channel depths are moderately deep,

and so experiences considerably less wave setup than a shallow unprotected location as described

in Hanslow and Nielsen (1992) and Tanaka and Tinh (2008).

Table 3-1 Peak Offshore Ocean Levels Adopted for Be llinger-Kalang River Estuary

Design Event Peak Level (m AHD)

Comment

Spring tide 0.69 This represents a typical tidal case as would be observed many times each month. The adopted value is Mean High Water Spring (MHWS) for Coffs Harbour.

King tide 1.08 This represents a less typical tidal case as would only be observed several times each year. The adopted value is Mean Higher High Water Solstice Spring (MHHWSS) for Coffs Harbour.

20-year ARI 1.60 This peak tidal level is expected on average to be exceeded once every 20 years and would occur due to a major storm event. Alternatively, this peak water level event can be interpreted as having a 5% chance of occurring in any given year. The adopted value is based on a 0.9 m AHD high tide, 0.4 m storm surge and 0.3 m wave setup.

100-year ARI 2.10 This peak tidal level is expected on average to be exceeded once every 100 years and would occur due to a major storm event. Alternatively, this peak water level event can be interpreted as having a 1% chance of occurring in any given year. The adopted value is based on a 0.9 m AHD high tide, 0.6 m storm surge and 0.6 m wave setup.

The predicted inundation extent for each of these four (4) design events was determined for the

five (5) different values of mean sea level including 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.

The selected design spring tide (as presented in Figure 3-2) is a seven (7) day period of predicted

tides from the 27th September, 2008 that closely matches the adopted design spring tide peak

water level presented in Table 3-1. The 0.4, 0.7, 0.9 and 1.4 m SLR time-series were calculated by

adding 0.4, 0.7, 0.9 and 1.4 metres to the predicted (MSL = 0 m AHD) tide.



The selected design king tide (as presented in Figure 3-3) is a seven (7) day period of predicted

tides from the 10th December, 2008 that closely matches the adopted design spring tide peak water

level presented in Table 3-1. The 0.4, 0.7, 0.9 and 1.4 m SLR time-series were calculated by

adding 0.4, 0.7, 0.9 and 1.4 metres to the predicted (i.e. MSL = 0 m AHD) tide.

Figure 3-2 Design Spring Tides

The design tide time-series for the 20-year and 100-year ARI events is based on seven (7) days of

predicted tides from the 25th December 2008 which include a 'high spring tide’ with a 0.91 m AHD

peak high water. A sinusoidal (cosine) storm surge with a four day (4) duration, was applied to this

design tide so that the peak high water is raised to meet the adopted design conditions as

presented in Figure 3-4.

The 0.4, 0.7, 0.9 and 1.4 metre SLR time-series were calculated by adding 0.4, 0.7, 0.9 and

1.4 metres to the present day (i.e. MSL = 0 m AHD) tide. An example of this is presented in Figure

3-5 for the 100-year ARI time-series. A summary of peak offshore water levels is presented in

Table 3-2.

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

0 24 48 72 96 120 144 168

Time (Hours)

Tide

Lev

el (

m A

HD

)

Spring SLR 0.0

Spring SLR 0.4

Spring SLR 0.7

Spring SLR 0.9

Spring SLR 1.4



Figure 3-3 Design King Tides

Table 3-2 Peak Offshore Tide Levels for Five SLR Sc enarios

Design Event 0.0 m MSL

+0.4 m MSL

+0.7 m MSL

+0.9 m MSL

+1.4 m MSL

Spring tide 0.69 1.09 1.39 1.59 2.09

King tide 1.08 1.48 1.78 1.98 2.48

20-year ARI 1.60 2.00 2.30 2.50 3.00

100-year ARI 2.10 2.50 2.80 3.00 3.50

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

0 24 48 72 96 120 144 168

Time (Hours)

Tide

Lev

el (

m A

HD

)

King SLR 0.0

King SLR 0.4

King SLR 0.7

King SLR 0.9

King SLR 1.4



Figure 3-4 Design Tides for 20 and 100yr ARI Events

Figure 3-5 100-year Design Tides

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

0 24 48 72 96 120 144 168

Tide

Lev

el (m

AH

D)

Time (Hours)

100 Year Design Tide

20 Year Design Tide

100 Year Design Surge

20 Year Design Surge

Predicted Design Tide

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

0 24 48 72 96 120 144 168

Time (Hours)

Tide

Lev

el (

m A

HD

)

100yr SLR 0.0

100yr SLR 0.4

100yr SLR 0.7

100yr SLR 0.9

100yr SLR 1.4



As the aim of the study was to determine the impact of SLR on changes to tidal inundation, the

model was run without high ‘design event’ fluvial inflows. For the 100-year and 20-year ARI design

tides events, fluvial inflows of 4800 ML/day and 2000 ML/day were adopted for the Bellinger and

Kalang River inflows which represent an approximate 5 percent exceedance discharge condition.

For the king tide and spring tide design tides events, fluvial inflows of 1000 ML/day and

400 ML/Day were adopted for the Bellinger and Kalang River inflows which represent an

approximately 10 percent exceedance discharge condition which is a typical high baseflow

condition.

3.1.4 Tidal Inundation Model Results and Extents

The revised Tuflow flood model was used to determine tidal inundation for twenty (20) design runs

including four (4) design events (spring tide; king tide; 20 yr ARI; and 100 yr ARI) for five (5)

different SLR scenarios 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.

Grid output of peak water levels and depths were obtained from each of the 20 model runs which

were used to create design flood inundation extents (see Appendix B), a summary of peak water

levels for each simulation as presented in Table 3-3, and long section plots of peak water level

profile for the Bellinger River (Figure 3-7 to Figure 3-10) Kalang River (Figure 3-11 to Figure 3-14).

A map of the long section profiles and reported locations is presented in Figure 3-6.

3.1.5 Comparison of Tidal Inundation to Fluvial Flooding

A comparison of peak tidal inundation levels to existing design fluvial flood peak levels indicates

that even with SLR, flood risk along the river is likely to be dominated by catchment derived flood

events. From Table 2-2 we can see that a 5-year ARI flood event will produce a peak at Urunga

and Repton of 1.98 m AHD and 2.39 m AHD respectively. Comparing those values to tidal flood

peaks presented in Table 3-3 reveals that even with 1.4 metre of SLR, a spring tide is still below

the current 5-year ARI flood level. Further examination also shows that it would take a SLR of

between 0.9 metres and 1.4 metres before a King Tide event would produce estuarine flooding

worse than the current 5-year ARI flood event.

Similarly, from Table 2-2 is it apparent that the current 100-yr ARI flood event will produce a peak

at Urunga and Repton of 3.29 m AHD and 4.57 m AHD respectively. Comparing those values to

tidal flood peaks presented in Table 3-3 reveals that even with 1.4 metres of SLR, a 100-year ARI

design tide is still below these levels.



Figure 3-6 Reported Peak Water Level Locations and Long Section Profiles



Table 3-3 Summary of Peak Tidal Water Levels (m AHD ) for Bellinger and Kalang Rivers

Design Event

Entrance Bellinger River Kalang River

Offshore Confluence Mylestom Repton Pacific Hwy (Bellinger) Fernmount Bellinger

Bridge Urunga Lagoon Urunga

U/S Newry Island

Picket Hill

Creek

Martells Rd (U/S Kalang)

Brierfield Bridge

Bed Level -4.54 -1.24 -2.31 -0.67 -2.50 -1.40 -1.51 -0.19 -1.10 -1.50 -2.54 -3.43 0.31

Spring 0.0mSLR 0.69 0.56 0.57 0.59 0.61 0.64 0.81 0.36 0.54 0.57 0.59 0.61 0.65

Spring 0.4mSLR 1.09 0.98 1.00 1.01 1.03 1.07 1.16 0.99 0.98 1.02 1.04 1.06 1.08

Spring 0.7mSLR 1.39 1.30 1.31 1.33 1.35 1.39 1.46 1.31 1.29 1.33 1.34 1.36 1.38

Spring 0.9mSLR 1.59 1.50 1.51 1.53 1.54 1.58 1.64 1.51 1.49 1.51 1.51 1.53 1.54

Spring 1.4mSLR 2.09 1.98 1.98 2.00 2.01 2.05 2.13 1.99 1.96 1.95 1.95 1.97 1.98

King 0.0mSLR 1.10 0.93 0.93 0.95 0.97 1.02 1.12 0.94 0.90 0.95 0.97 1.00 1.02

King 0.4mSLR 1.50 1.36 1.36 1.38 1.40 1.45 1.53 1.38 1.34 1.37 1.38 1.41 1.43

King 0.7mSLR 1.80 1.66 1.67 1.68 1.70 1.74 1.82 1.67 1.64 1.64 1.64 1.66 1.67

King 0.9mSLR 2.00 1.85 1.85 1.87 1.89 1.93 2.01 1.87 1.83 1.80 1.81 1.83 1.84

King 1.4mSLR 2.50 2.31 2.31 2.31 2.33 2.37 2.43 2.33 2.28 2.21 2.21 2.23 2.24

20yr ARI 0.0mSLR 1.60 1.53 1.56 1.57 1.59 1.63 2.08 1.54 1.53 1.55 1.55 1.57 1.71

20yr ARI 0.4mSLR 2.00 1.91 1.93 1.94 1.96 2.01 2.28 1.92 1.90 1.89 1.90 1.93 2.02

20yr ARI 0.7mSLR 2.30 2.18 2.19 2.21 2.22 2.25 2.44 2.19 2.17 2.13 2.14 2.17 2.25

20yr ARI 0.9mSLR 2.50 2.37 2.37 2.38 2.39 2.43 2.60 2.38 2.35 2.29 2.29 2.32 2.39

20yr ARI 1.4mSLR 3.00 2.80 2.80 2.81 2.82 2.85 2.97 2.82 2.77 2.71 2.73 2.76 2.81

100yr ARI 0.0mSLR 2.10 2.00 2.01 2.03 2.05 2.09 2.33 2.01 1.98 1.96 1.97 2.00 2.09

100yr ARI 0.4mSLR 2.50 2.36 2.36 2.37 2.39 2.42 2.60 2.37 2.34 2.27 2.28 2.30 2.38

100yr ARI 0.7mSLR 2.80 2.62 2.61 2.61 2.63 2.66 2.79 2.64 2.59 2.50 2.50 2.53 2.59

100yr ARI 0.9mSLR 3.00 2.79 2.78 2.78 2.79 2.82 2.94 2.81 2.76 2.67 2.68 2.71 2.77

100yr ARI 1.4mSLR 3.50 3.24 3.23 3.20 3.20 3.23 3.31 3.28 3.21 3.19 3.20 3.23 3.27

Bellingen Shire Estuary Inundation Mapping 31 Estuary In undation Modelling


Figure 3-7 Bellinger River Peak Water Level Long Se ction (Design Spring Tides)

Figure 3-8 Bellinger River Peak Water Level Long Se ction (Design King Tides)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)

0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR

Bellinger - Spring Tide

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Bellinger - King Tide



Figure 3-9 Bellinger River Peak Water Level Long Se ction (Design 20-year ARI Tides)

Figure 3-10 Bellinger River Peak Water Level Long S ection (Design 100-year ARI Tides)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Bellinger - 20yr ARI

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Bellinger - 100yr ARI



Figure 3-11 Kalang River Peak Water Level Long Sect ion (Design Spring Tides)

Figure 3-12 Kalang River Peak Water Level Long Sect ion (Design King Tides)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Kalang - Spring Tide

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Kalang - King Tide



Figure 3-13 Kalang River Peak Water Level Long Sect ion (Design 20-year ARI Tides)

Figure 3-14 Kalang River Peak Water Level Long Sect ion (Design 100-year ARI Tides)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Kalang - 20yr ARI

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0500010000150002000025000

Chainage (m)

Pea

k W

ater

Lev

el (

m A

HD

)


Kalang - 100yr ARI



3.2 Dalhousie and Oyster Creeks Due to the small relatively small size of Dalhousie Creek and Oyster Creeks hydrodynamic

modelling was not required to determine tidal inundation extents. The dynamic nature of both creek

entrances and the lack of water level measurements at either location required due consideration

to determine appropriate design conditions for these two waterbodies, which is summarised in the

following sections.

3.2.1 Background and Key Processes

Dalhousie Creek has a waterway area of 0.075 km2 and a catchment area of 6.5 km2 (although it

should be noted the presence of two large farm dams is likely to significantly reduce runoff to the

creek). A recent estimate of natural entrance opening is twice yearly.

Oyster Creek has a waterway area of 0.15 km2 and a catchment area of 16.1 km2 being

predominantly comprised of forested and cleared farming land. There are no published estimates

of natural entrance opening occurrence though it is likely to be similar to Dalhousie Creek (i.e.

about twice each year on average).

Both creeks are defined as ICOLLs (Intermittently Closed and Open Lakes or Lagoons) due to the

dynamic behaviour of their entrances and variable interaction with the ocean. The condition of an

ICOLL entrance is the result of a dynamic balance between tidal inflow and outflows, wave driven

littoral sand transport, and intermittent flood events. Within NSW, approximately 70% of ICOLLs

are disconnected from the ocean (i.e. closed) for the majority of the time (Haines, 2008). Water

levels within a closed ICOLL are influenced by changes to the berm height, catchment runoff

volumes (i.e. rainfall and catchment area), evaporation and the stage-volume characteristics of the

water body.

Both ICOLLs in the study area have entrances that are exposed to wave processes which in the

absence of significant tidal exchange or fluvial flows are able to produce significant net onshore

transport of sediment which tend to rapidly constrict the entrance and subsequently close the

ICOLL following a breakout event. Once the ICOLL is closed, the entrance berm level increases in

height due to wave run-up and aeolian (wind) processes until rainfall events produce sufficient

runoff to raise water levels to breach the berm and re-open the ICOLL naturally.

Haines (2008) reports that natural (i.e. unmanaged) maximum berm heights for NSW ICOLLs

ranges between 2 to 3 metres and is influenced by the frequency of lagoon opening which tends to

be a function of the ratio of waterway area to catchment area (i.e. for an ICOLL with a large

catchment but small waterway area, a given rain event will cause a larger rise in water level, than

would occur for an ICOLL with a smaller catchment but larger waterway area). Because both

lagoons have a large (i.e. >0.86) ratio of catchment to waterway area, they are expected to open

fairly frequently (several time per year) and hence berm building processes would be fairly limited.

3.2.2 Determination of ICOLL Design Water Levels

Due to the dynamic nature of ICOLL entrances and processes which influence water levels with

ICOLLs, a different set of design conditions (compared to that described in Section 3.1.3) to

determine potential SLR impact on Dalhousie and Oyster Creeks was required. To determine SLR



impact for both infrastructure and ecological assets, a range of pragmatic design conditions (see

Table 3-4) were required, that reflect both the uncertainty in determining design conditions in the

absence of short of long term water level data sets, and the relative steep sides to the water ways

(which means that small changes in water level result in small changes to the inundated area).

In addition to the selection of the four design events for mapping purposes, an indication of water

level exceedance at the ICOLLs was required to better understand the potential impact of SLR on

the estuarine ecology for the two ICOLLs. The approximated water level exceedance curves for the

two sites was used to further inform the selected design levels used for the mapping of design

inundation.

Manly Hydraulic Laboratory (MHL) collects water level data for the NSW Government at a range of

estuaries and ICOLLs along the NSW coastline, however, no water level data are available for

either ICOLL for use in this study. The behaviour of ICOLLs has been examined at a range of

similar sites allowing likely water level entrance behaviour to be inferred at Dalhousie and Oyster

Creeks. The ratio of catchment area to waterway area and the degree of exposure to wave

processes are key influences of ICOLL water levels.

Of the approximately 25 ICOLLs (out of about 70 in NSW greater than hectare in surface area)

where water level records exist (MHL, 2014), two similar ICOLLs (with respect to

catchment:waterway area ratio and entrance condition) are Curl Curl Lagoon and Werri Lagoon.

Water level exceedance data (as provided in MHL (2014) for the two lagoons was averaged to

produce a single ‘design’ series of ICOLL water level exceedance (see Figure 3-15). Wainwright

and Baldock (2010) explain that increased ocean levels due to SLR will result in a corresponding

increase in ICOLL berm heights, which means that for the purposes of this assessment, ICOLL

water levels will increase in line with changes to MSL as presented in Figure 3-15 and Table 3-5.

3.2.3 Determination of ICOLL Design Flood Extents

Tidal inundation extents for Dalhousie Creek and Oyster Creek were determined using a ‘bath tub’

approach. A DEM of the two creeks based on ALS data was used in conjunction with the design

inundation levels presented in Table 3-5 was used to create tidal inundation extents. Approximate

tidal inundation extents (see Appendix B) were obtained by contouring the DEM at the adopted

peak inundation level for each SLR scenario.



Table 3-4 Peak Ocean Levels for Dalhousie and Oyste r Creeks

Design Event

Peak Level (m AHD)

Comment

Low Lagoon Water Level

(~85% Exceedance)

0.7 This water level is likely to be exceeded approximately 85% of the time in the ICOLL and hence represents a low lagoon water level. Immediately following a lagoon breakout, the water level may fall below this level until the entrance is significantly closed or constricted at which time the water level would begin to exceed 0.7 m AHD. It is likely that the lagoon level would only be below this level for a few days to weeks in any year.

High Lagoon Water Level

(~15% Exceedance)

1.6 This water level is likely to be exceeded approximately 15% of the time within the ICOLL. Following lagoon closure, small consecutive rainfall events (and potential wave overtopping) would gradually fill the lagoon until a breakout opens the ICOLL. It is likely that the lagoon level would only be above this level for a few weeks to months in any year.

Infrequent Lagoon Water Level

(20-year ARI)

2.2 Adopted infrequent lagoon level is the suggested 5% AEP (i.e. 1 in 20-year ARI) ocean tide for ICOLLs (DECCW, 2010). Potential design components include 0.9 m AHD high tide, 0.4 m storm surge, and 0.9 m wave setup.

Rare Lagoon Water Level

(100-year ARI)

2.6 Adopted rare lagoon level is the suggested 1% AEP (i.e. 1 in 100-year ARI) ocean tide for ICOLLs (DECCW, 2010). Potential design components include 0.9 m AHD high tide, 0.6 m storm surge, and 1.1 m wave setup.

Figure 3-15 Adopted Design ICOLL Water Level Excee dance Curves

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 10 20 30 40 50 60 70 80 90 100

Time Exceeded (%)

Lago

on W

ater

Lev

el (

m A

HD

)

Design ICOLL WL 0 m SLR

Design ICOLL WL 0.4 m SLR






Table 3-5 ICOLL Peak Inundation Level for five SLR Scenarios

Design Event

0 m MSL

+0.4 m MSL

+0.7 m MSL

+0.9 m MSL

+1.4 m MSL

Low Lagoon Water Level

(~85% Exceedance)

0.7 1.1 1.4 1.6 2.1

High Lagoon Water Level

(~15% Exceedance)

1.6 2 2.3 2.5 3

Infrequent Lagoon Water Level

(20-year ARI)

2.2 2.6 2.9 3.1 3.6

Rare Lagoon Water Level

(100-year ARI)

2.6 3.0 3.3 3.5 4.0

Bellingen Shire Estuary Inundation Mapping 39 Estuary In undation Risk Assessment


4 Estuary Inundation Risk Assessment

The estuary inundation modelling results presented in Section 3 are used here to make an

assessment of the land and assets (including water, sewer, stormwater and roads) that are likely to

be impacted by periodic storm events, under present and future SLR scenarios. To assist with the

interpretation of ecological impacts outlined in Section 6, the risk assessment also considers

inundation of vegetation communities, habitats and other features of biodiversity significance

covering areas within and adjacent to the predicted inundation area.

The process outlined below is consistent with that applied to the Bellingen Coastal Zone

Management Study (CZMS) for the open coastal areas (BMT WBM, 2014a). By utilising the same

methodology, the outcomes can be more easily integrated within the outcomes of the CZMP (BMT

WBM, 2014b) at a later stage than if an alternate risk methodology was applied.

4.1 Application of a Risk-Based Framework A risk-based framework is a robust methodology for dealing with consequences that are uncertain

or have limited data, or for impacts with uncertain timeframes. This approach is therefore

particularly applicable to coastal hazards impacts and the impacts of predicted sea level rise,

where there is considerable uncertainty regarding when and if impacts will manifest. Uncertainties

associated with future climate change present huge challenges to local government and the wider

community, who need to consider and manage future risks. Decisions made today are likely to

have ramifications for up to 100 years or more (depending on the type and scale of development),

and so consideration of an extended timeframe is essential, even though risks may not manifest for

several decades.

The risk assessment process is adapted from the Australian Standard Risk Management Principles

and Guidelines (AS/NZS ISO 31000:2009), as described below and presented schematically in

Figure 4-1. The use of a risk-based approach for managing coastal hazards such as SLR

inundation is a requirement of the latest CZMP guidelines, and accords with current international

best practice for natural resource management as follows:

• Identify the Risk – the risk arises from estuary inundation during high tides combined with

storms and sea level rise. The inundation hazard was estimated for the Bellinger-Kalang

Estuary in Section 3 and is presented as hazard maps in Appendix B.

• Analyse the Risk – estuary inundation is the event to be analysed through risk management. In

this case, both likelihood and consequence of the hazard needs to be analysed. The

combination of likelihood and consequence defines the overall level of risk which are

categorised as extreme, high, medium or low.

The likelihood of risk is related to the extent of the estuary inundation hazard, now and in the

future. The likelihood of estuary inundation at the immediate, 2050, 2100 timeframes is defined

in Section 4.2.

Bellingen Shire Estuary Inundation Mapping 40 Estuary Inundation Risk Assessment


Figure 4-1 Risk Management Framework (ISO 31000:20 09) adapted to Coastal Zone Management

Establishing the context What are our objectives for Coastal Zone Management?

Com

mun

icat

ion

and

Con

sulta

tion

S

take

hold

er a

nd C

omm

unity

Lia

ison

Mon

itorin

g an

d R

evie

w

Are

we

mee

ting

our

Per

form

ance

Indi

cato

rs?

Risk Assessment

Risk Identification What are the built, natural and community assets at risk from coastal hazards?

Risk Analysis What are the likelihood and the consequence of each coastal risk? What is the level of risk (high, medium low)?

Risk Evaluation What is a tolerable level of risk? Are there controls / mitigating actions already in place?

Risk Treatment Options What management strategies can we use to reduce the level of risk to a tolerable level? What are the costs and benefits of the strategies? At what trigger level do we implement the strategies?

Implement Management Strategies



The consequence of the risk relates to the impact of the hazard upon the land and existing and

future assets, including the aesthetic, recreational, ecological and economic values associated

with the estuary. A formal Risk Assessment Workshop with stakeholders to assess the

consequence of coastal hazards was conducted as part of the Bellingen CZMS. The outcomes

of that workshop are detailed in Appendix D of BMT WBM (2014) and are summarised in

Section 4.3.

• The consequence and likelihood were combined (using Geographical Information System (GIS)

processing) to determine the level of risk for assets and land in the study area. The key output

of the risk assessment is a register of estuary assets and their level of risk for planning

timeframes which is summarised in Section 4.5 and tabulated in Appendix C.

• Evaluate the Risks – the level of risk that is deemed acceptable, tolerable and intolerable have

been adopted from that defined in the Bellingen CZMS (2014). The evaluation criteria define the

intolerable risks that must be treated as a priority and to which management effort shall be

directed, which is discussed further in Section 4.4.

• Treat the Risks – the process of developing management options is directly related to reducing

or eliminating intolerable risks where possible. Tolerable (low) risks can be flagged for

monitoring, with no further resources necessary. Management options can be designed to

reduce the likelihood of the risks (e.g. development controls), or reduce the consequence of the

risk (e.g. emergency management to reduce the consequence of inundation) or both.

Management options first need to be technically viable for the study area. A triple bottom line

(social, economic and environmental) cost benefit analysis is then used to determine which of

the risk treatments will provide the greatest benefit (relative to cost) in treating the highest

priority risks. Management options are mentioned briefly in Section 4.5.

For existing development, the timeframes over which hazards may manifest is uncertain and so

a trigger for implementing the options has been flagged. Setting triggers ensures the

management option and associated resources are not utilised until it is absolutely necessary to

do so, which is particularly important for difficult and costly, but necessary, options. This is

described further in Section 4.6.

Implement Management Strategies (Risk Treatments) – the CZMP provides the forum

detailing how the recommended management options (risk treatments) shall be implemented

(costs, timeframes, resources) and funded. The outcomes of this study have the potential to be

integrated within the Bellingen Coastal Zone Management Plan at a later stage.

4.2 Likelihood of Estuary Inundation

4.2.1 Likelihood Scale

The hazard definition process is suited to defining the ‘likelihood’ or probability of occurrence of the

inundation hazard. A scale of ‘likelihood’ or the probability of occurrence for a hazard impact based

upon the Australian Standard for Risk Management (AS/NZS ISO 31000:2009) and its companion

document (HB 436:2004) was derived, as given in Table 4-1. The timeframes over which SLR

inundation hazard probabilities were assessed is defined in Table 4-2, namely the immediate, 2050

and 2100 planning horizons, which is consistent with the CZMP Guidelines for coastal planning.



The categories were rationalised and focus was given to ‘Almost Certain’, ‘Unlikely’ and ‘Rare’

probabilities (referred to herein as ‘Almost Certain, ‘Best Estimate’ and ‘Worst Case’; see Table

4-1) for the immediate, 2050 and 2100 planning horizons. These categories are presumed to

provide a sufficient level of detail for planning purposes. As SLR projections and assessment of the

probability of hazard impacts improves into the future, it is expected that the approach to the

definition of hazard will be incorporated into future revisions of the Risk Assessment.

Table 4-1 Risk Likelihood / Probability for Coastal Hazards

Probability Description Hazard Descriptor

Almost Certain There is a high possibility the event will occur as there is a history of frequent occurrence.

Almost Certain

Likely It is likely the event will occur as there is a history of casual occurrence. Insufficient data to

define Possible There is an approximate 50/50 chance that the

event will occur.

Unlikely There is a low possibility that the event will

occur, however, there is a history of infrequent or isolated occurrence.

Best Estimate

Rare It is highly unlikely that the event will occur,

except in extreme / exceptional circumstances, which have not been recorded historically.

Worst Case

Table 4-2 Timeframes for Coastal Planning

Timeframe Coastal Hazard

Immediate Present day conditions (e.g. 2014)

2050 Expected conditions by 2050

2100 Expected conditions by 2100

4.2.2 Likelihood of Coastal Inundation

The estuary inundation hazard refers to inundation due to elevated ocean water levels during a

storm that either propagate into river or lagoon entrances or act as a tailwater level impeding

outflow, thereby elevating their upstream water level. The rationale behind the design estuary

inundation levels and their probability for all planning periods is summarised below in Table 4-3.



Table 4-3 Estuary Inundation Likelihood Summary

Probability Immediate 2050 2100

Almost Certain 1 in 20 yr storm surge and wave set

up

As per immediate As per immediate

Likely NA 1 NA 1 NA 1

Possible NA 1 NA 1 NA 1

Best Estimate (Unlikely)

1 in 100 yr storm surge and wave set

up

1 in 100 yr storm surge and wave set up + 0.4

m SLR and climate change impacts

1 in 100 yr storm surge and wave set up + 0.9 m SLR and climate change

impacts

Worst Case (Rare)

1 in 100 yr storm surge and wave set-

up

+ extreme climatic conditions (e.g.

tropical cyclone, 1 in 1000 year east coast

low)

1 in 100 yr storm surge and wave set up + 0.7 m SLR and

climate change impacts

1 in 100 yr storm surge and wave set up + 1.4 m SLR and climate change

impacts

1 NA = Not Assessed

In defining the likelihood of coastal inundation within the immediate timeframe, it was considered:

• ‘Almost Certain’ would be equivalent to a 20-year ARI event;

• ‘Best Estimate’(unlikely) would be equivalent to a 100-year ARI event; and

• ‘Worst Case’ (rare) would be equivalent to a 100-year event with the addition of an extreme

climatic condition, resulting in still water levels (excluding wave set-up) roughly equivalent to a

1000-year ARI. Such an event was estimated to add 0.2 metres to the 100-year ARI water level.

Given the potential for tropical cyclones to track further southwards due to climate change or

more extreme storms due to climate change or natural variability over the immediate to 2100

period, it is reasonable to plan for greater than expected ocean water levels in the future.

For future planning periods (2050, 2100), extreme ocean water levels will additionally include SLR,

as well as minor projected changes to storm surge and wave height. The design inundation levels

are thus:

• an ‘Almost Certain’ probability for a 20-year ARI event, without SLR, and this approach provides

a hazard level irrespective of the rate of sea level rise. This is consistent with planning advice

given in the Coastal Protection Act 1979 and related documents for defining coastal risk areas;

• a ‘Best Estimate’(unlikely) probability of a 100-year ARI event plus predicted sea level rise, plus

increased wave set-up and storm surge due to climate change; and

• a ‘Worst Case’ (rare) probability of a 100-year ARI event plus greater than predicted sea level

rise (1.4 metres by 2100), or an extreme climatic condition (e.g. a 1000-year ARI still water level

event, excluding wave set-up) plus predicted sea level rise, whichever is greatest.



Details of modelling undertaken for the various SLR and design inundation events described above

are provided in Section 3.

4.3 Consequence of Estuary Inundation

4.3.1 Consequence Scale

The other component of risk is consequence.

The consequence of the impact from estuary inundation relates to the land and assets affected by

the predicted inundation extent. It should be noted that the impact of the hazard being assessed

within this risk assessment is periodic and temporary (unlike the impact of coastal recession which

results in the long-term permanent loss of land, or permanent inundation due to sea level rise).

A consequence scale was developed that is relevant to estuary inundation to coastal land and

assets and its effect across the entire community and the timeframe (up to 100 years) for coastal

risk planning. The consequence scale follows a triple bottom line approach, to determine the

consequence to the society and community, environment and economy.

Terminology of ‘catastrophic’, ‘major’, ‘moderate’, ‘minor’, and ‘insignificant’ was adopted for the

consequence scale, which is consistent with the terminology adopted by Standards Australia

(2004) Handbook Risk Management Guidelines Companion, which accompanies the Risk

Management Principles and Guidelines. The consequence scale adopted is shown in Table 4-4.

4.3.2 Register of Public and Private Assets Potentially Affected

A variety of coastal assets representing various land use, facilities and features (including

environmental features) of the Bellinger-Kalang Estuary study area were identified based upon GIS

processing of:

• spatial mapping of land zoning, land tenure, cadastre and aerial photography;

• mapping of stormwater assets, wastewater and water supply assets, heritage items, parks,

dune vegetation, public buildings, roads and community assets;

• information regarding assets (social, cultural, recreational, economic) from various reports; and

• details for other assets provided through discussions with Council.

The asset types identified within the study area are listed in Table 4-6. GIS layers of coastal assets

in study area were consolidated and consequence values assigned where estuary inundation is

predicted to occur. For each of the coastal assets, a consequence value was established based on

the findings of the Risk Assessment Workshop undertaken during preparation of the Bellingen

CZMS (BMT WBM, 2014). These consequence values have been mostly adopted for the present

risk assessment, with the exception of the ecological assets, which adopts a more sophisticated

consequence scale developed around the lowest tolerance value for either saltwater or inundation

(refer Table 4-5). The consequence value, assigned to each of the assets in the study area is

summarised in Table 4-6.



Table 4-4 Consequence Scale for Estuary Inundation

Consequence Society / Community Environment Economy

Catastrophic

Widespread permanent impact to community’s services, wellbeing, or culture (e.g. > 50 % of community

affected), or

national loss, or no suitable alternative sites exist.

Widespread, devastating / permanent impact (e.g. entire

habitat destruction), or loss of all local

representation of nationally important species (e.g. endangered species). Recovery is unlikely.

Damage to property, infrastructure, or

local economy > $15 million*

Major

Major permanent or widespread medium term disruption to

community’s services, wellbeing, or culture (e.g. 50 % of community

affected), or regional loss, or

Few, if any, suitable alternative sites exist.

Widespread permanent or semi-permanent impact, or

widespread pest / weed species proliferation, or semi-

permanent loss of entire regionally important habitat. Recovery may take several

years, if at all.

Damage to property, infrastructure, or

local economy >$2 million

Moderate

Minor long-term or major short-term (mostly reversible) disruption to

services, wellbeing, or culture of the community (e.g., up to 25 % of

community affected), or sub-regional loss, or

Some suitable alternative sites exist.

Significant environmental changes isolated to a

localised area, or loss of regionally important habitat in one localised area. Recovery

may take several years.

Damage to property, infrastructure, or local economy

>$250,000** - $2 million

Minor

Small to medium short term (reversible) disruption to services, wellbeing, finances, or culture of

the community (e.g., up to 10 % of community affected), or

local loss, or many alternative sites exist.

Environmental damage of a magnitude consistent with

seasonal variability. Recovery may take one year.


>$50,000 - $250,000

Insignificant

Very small short-term disruption to services, wellbeing, finances, or

culture of the community (e.g. up to 5 % of community affected), or

neighbourhood loss, or

numerous alternative sites exist.

Minimal short-term impact, recovery may take less than 6 months, or habitat affected with many alternative sites

available.


<$50,000



Table 4-5 Updated Ecological Community Consequence Ratings

Ecological Community Relative

Inundation Tolerance

Relative Saltwater Tolerance

Minimum Saltwater Tolerance

Inundation Consequence

Level

Coastal Saltmarsh EEC Medium High Medium Moderate

Freshwater EEC High Low Low Major

Littoral Rainforest EEC Low Low Low Major

Lowland Rainforest EEC Low Low Low Major

Lowland Rainforest on Floodplain EEC Low Low Low Major

Mangrove High High High Minor

Sub-tropical Coastal Floodplain Forest EEC Low Low Low Major

Swamp Oak Floodplain Forest EEC Medium Medium Medium Moderate

Swamp Sclerophyll Forest EEC High Low Low Major

Table 4-6 Consequences Ascribed to Assets in the St udy Area

Asset Category / Asset Name Coastal Inundation Consequence Level

Town Centre, Residential and Rural Property

Neighbourhood / Local Centre Major

Residential Property Moderate

Rural Property Moderate

Essential Community Facilities (e.g. Hospitals) Catastrophic

Various Community Buildings (e.g. Schools, Public Hall) Major

Primary Production, Forestry and Industry

Primary Production Lots Moderate

Forestry Land Minor

Industrial Land Moderate

Infrastructure Land Minor

Transport Infrastructure

Major Roads Major

Bridges Major

Culverts Major

Minor / Local Roads Moderate

Railway Major

Other Infrastructure

Water Main Services Minor

Wastewater Infrastructure Major

Stormwater Drainage Infrastructure Moderate



Asset Category / Asset Name Coastal Inundation Consequence Level

Community Infrastructure

Holiday Parks and Reserves Moderate

Boat Ramps and Car Parks Insignificant

Public Recreation (e.g. sport grounds) Minor

Private Recreation Facilities Minor

Amenities / Blocks / Sheds Minor

Beach Access (Pedestrian & 4WD) Insignificant

Heritage

Built Items Sensitive to Flooding Moderate

Non-flooding Sensitive Items / Sites Insignificant

Landscape / Vegetation Items Minor

Cultural / Archaeological Sites Minor

Natural Assets

Beaches Insignificant

Foredune and Hind Dunes Insignificant

Creek Entrances Insignificant

National, State and Local Parks/Reserves Minor

Environmental Protection Zones Minor

Ecological Communities (low tolerance1) Major

Ecological Communities (medium tolerance1) Moderate

Ecological Communities (high tolerance1) Minor

Waterways

Rivers, Creeks, Lagoons Insignificant

4.4 Analysis of the Level of Risk Within a risk assessment approach, risk is defined as likelihood X consequence. A risk matrix

defining the level of risk from the various combinations of likelihood and consequence was

developed for the estuary inundation risk assessment, as given in Table 4-7.

As for the likelihood and consequence scales, the risk matrix differs from that used for other risk

assessments (e.g. health and safety, operational risk and so on), as it has been designed for the

timeframes and considerations involved in coastal hazard planning.

Using the risk matrix to determine the level of risk from the combination of likelihood and

consequence ascribed to the different assets, a comprehensive asset register showing the level of

risk from SLR inundation within the study area was prepared (see Appendix C). The likelihood and

consequence values were assigned in a GIS to the hazard zones and assets respectively, and then

combined to produce an overall level of risk, using the risk matrix scores in Table 4-7.



The risk register details the various assets affected by SLR inundation and the level of risk at

present, 2050 and 2100 timeframes. The level of risk forms the basis for prioritising which assets

require treatment. Recommended management options and triggers for implementation are

discussed further in Section 4.5 and Section 4.6 and respectively.

Table 4-7 Risk Matrix for Estuary Inundation

Consequence

Insignificant Minor Moderate Major Catastrophic

Like

lihoo

d

Almost Certain Low Medium High Extreme Extreme

Likely Low Medium High High Extreme

Possible Low Medium Medium High Extreme

Unlikely Low Low Medium High Extreme

Rare Low Low Low Medium High

4.5 Estuary Inundation Risks Register The register of estuary inundation risk to assets is given in Appendix C. This table highlights those

assets which are deemed to have an intolerable level of risk and should thus be prioritised for

treatment. A summary of the risk register showing the area of inundation for each asset category

and suburb for the immediate, 2050 and 2100 timeframe is shown in Figure 4-2, Figure 4-3 and

Figure 4-4 respectively.

Of all the areas at risk from coastal inundation, approximately 30% to 40% of these are deemed to

have an intolerable level of risk (i.e. high or extreme) under both present and future scenarios. As

expected, both Urunga and Raleigh are the ‘hot spot’ suburbs with the greatest areas of intolerable

risk from inundation within Bellingen Shire, due to their low lying nature and proximity to the estuary

mouth.

Other key points to note from the risk register summary charts are:

• Ecological communities are by far at the greatest risk (particularly at Urunga), with significance

occurrences of residential, rural, primary production and recreation also experiencing intolerable

levels of risk under present and future timeframes;

• Mylestom, Repton and Bellingen may experience the smallest inundation impact for the

immediate, 2050 and 2100 timeframes with the vast majority of asset categories not at risk;



• Increasing areas of residential development at Urunga may be at risk under future scenarios

compared to the immediate timeframe. Residential development at all other suburbs is not at

risk from SLR inundation for the immediate and 2050 timeframes. Some medium risk inundation

of residential development at Raleigh is however calculated for the 2100 timeframe;

• Projected SLR for the 2050 and 2100 timeframes may exacerbate the already large area of

primary production land at risk at Raleigh; and

• Forestry, primary production and rural land is typically at risk at many of the suburbs and most

susceptible to potential SLR inundation due to its proximity to the main estuary waterways.

Bellingen Shire Es tuary Inundation Mapping 50 Estuary Inundation Risk Assessment


Figure 4-2 Summary of Estuary Inundation Risk for the Immediate Timeframe

Note: Charts show the area of inundation (ha) predicted for each asset category within suburbs of the study area

0 50 100 150 200 250 300 350

URUNGA

Residential Development

Rural Landscape

Primary Production

Forestry

General Industrial

Roads / Rai l / Infrastructure

Community (+ BSC) Facilities

Recreation

Ecological Community

Parks, Reserves and Open Space (+ beach and dunes)

Environmental Protection Zone

Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

RALEIGH


Rural Landscape

Primary Production

General Industrial






Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

MYLESTOM

Rural Landscape


Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

REPTON


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

BRIERFIELD


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

FERNMOUNT


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350

BELLINGEN


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

Bellingen Shire Estuary Inundation Map ping 51 Estuary Inundation Risk Asse ssment


Figure 4-3 Summary of Estuary Inundation Risk for the 2050 Timeframe


0 50 100 150 200 250 300 350 400 450 500

URUNGA


Rural Landscape

Primary Production

Forestry

General Industrial

Roads / Rail / Infrastructure


Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

RALEIGH


Rural Landscape

Primary Production

General Industrial






Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

MYLESTOM

Rural Landscape


Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

REPTON


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

BRIERFIELD


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

FERNMOUNT


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 50 100 150 200 250 300 350 400 450 500

BELLINGEN


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low



Figure 4-4 Summary of Estuary Inundation Risk for the 2100 Timeframe


0 100 200 300 400 500 600 700 800

URUNGA


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

RALEIGH


Rural Landscape

Primary Production

General Industr ial






Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

MYLESTOM

Rural Landscape


Recreation




Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

REPTON


Rural Landscape

Primary Production

Forestry

General Industr ial



Recreation




Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

BRIERFIELD


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

FERNMOUNT


Rural Landscape

Primary Production

Forestry

General Industr ial



Recreation




Heritage

Extreme

High

Medium

Low

0 100 200 300 400 500 600 700 800

BELLINGEN


Rural Landscape

Primary Production

Forestry

General Industrial



Recreation




Heritage

Extreme

High

Medium

Low



4.6 Triggers for Implementation It is apparent from the risk assessment that some intolerable risks are not expected to eventuate

until 2050 or 2100. In this case, implementing a management action now, particularly where the

option is difficult or costly, may be premature and cannot account for the uncertainty of when or to

what extent the hazard may actually eventuate in the future.

While a decision regarding future intent is necessary at the present timeframe for intolerable risks,

the action may not require implementation at present. Fisk and Kay (2010) provide a method for

setting triggers for climate change adaptation actions along a time continuum. The trigger points

are set to flag the ‘level of acceptable change’ where more pro-active or decisive actions must be

implemented in order to avoid an undesirable impact. The trigger setting method is demonstrated in

Figure 4-5.

Figure 4-5 Continuum Model for Climate Change Adap tion Action



A triggered approach avoids actions being implemented until it becomes necessary, with time in

the interim to improve data/knowledge of the impact, source funding, prepare approvals and

formulate designs. It also recognises that SLR / climate change impacts may not eventuate. If this

is the case, then the community has not been unnecessarily burdened by having to adopt costly

management responses. Until the trigger is reached, ‘No regrets’ options should be implemented to

reduce the need for management by future generations (e.g. reducing the intensity of development

in at risk areas). The approach should therefore be to apply ‘No regrets’ actions at the current

timeframe and to set triggers for implementing actions for existing developments.

The majority of options suggested within this study are considered to be “No regrets” options, to

assist Council in the period of acceptable risk to plan for future implementation of more substantial

actions. For options such as the Asset Management Plan and Audit of Existing Assets, it has been

recommended that a trigger be set by Council. Guidance regarding setting of triggers for estuary

inundation is given below.

Setting triggers for estuary inundation requires careful consideration of the tolerability of specific

assets to the type of inundation hazard. That is, some assets may become unusable when

inundation occurs once a year, others may remain functional with more frequent inundation. The

trigger thus needs to be specific to the asset. The trigger may then be defined as a frequency of

inundation (e.g. a certain number of times per year), which would require monitoring at individual

assets. Alternatively, the frequency may be redefined as a depth of inundation, which is best

measured and monitored via water level gauges.

Bellingen Shire Estuary Inundation Mapping 55 Estuary Ecological Modelling


5 Estuary Ecological Modelling

In order to understand the ecological impacts of SLR, statistics on long term (i.e. annual) water

level and salinity conditions were obtained. In order to develop these statistics, a suitable estuary

(hydrodynamic) model capable of simulating a continuous longer-term period of water levels and

salinity concentration was required.

In addition to the estuary model, a catchment (hydrologic) model was required to estimate

freshwater contributions to the estuary which influence the water levels and longitudinal salinity

variations along the Bellinger and Kalang Rivers.

Development of the hydrologic inputs (catchment model) and estuary hydrodynamic model is

outlined below in Section 5.1 and Section 5.2 respectively.

5.1 Development of Hydrological Inputs

5.1.1 The Source Modelling Framework

For this study, the eWater Source Modelling Framework (herein referred to as Source)

(http://www.ewater.com.au/products/ewater-source/) was used to simulate the rainfall-runoff

processes occurring in the Bellinger Kalang River catchment (the study catchment).

Source is an application that can be used for both catchment and river modelling. Source provides

a flexible structure that allows you to select a level of model complexity appropriate to the problem

at hand and within any constraints imposed by your available data and knowledge. Users can

construct models by selecting and linking component models from a range of available options

(Delgado et al., 2012).

Source is designed to:

• Support the construction and operation of river models that mimic river behaviour. Water

resource systems can be analysed for periods that range from days to many years; and

• Allow you to construct and interrogate water and contaminant transport models to assess the

impact of future change, on parameters of interest.

Source for Catchments integrates an array of models, data and knowledge that can be used to

simulate how climate and catchment variables (rainfall, evaporation, land use, vegetation) affect

runoff, sediment and contaminants. The output can be used to offer scenarios and options for

making improvements in a catchment. Source also features a wide range of data pre-processing

and analysis functions that allows users to create and compare multiple scenarios, assess the

consequences, and report on the findings.



5.1.2 Model setup

5.1.2.1 Overview

The Source model is based on the following building blocks:

• Sub-catchments: The sub-catchment is the basic spatial unit, which is then divided into

hydrological response units (or functional units) based on a common response or behaviour

such as land use. Within each functional unit, three models can be assigned: a rainfall-runoff

model, a constituent generation model and a filter model;

• Nodes: Nodes represent sub-catchment outlet, stream confluences or other places of interest

such as stream gauges or dam walls. Nodes are connected by links, forming a representation of

the stream network; and

• Links: Links represent the river reaches. Within each link, a selection of models can be applied

to route or delay the movement of water along the link; or modify the contaminant loads due to

processes occurring within the links, such as decay of a particular constituent over time.

The Source for Catchments (hydrological) model was configured to estimate the quantity of surface

runoff generated under existing conditions by the major subcatchments draining to Bellingen and

Brierfield, which account for approximately 82% of the total study catchment area. Estimates of

daily streamflow at those two locations were adopted to define upstream freshwater inputs to the

2D estuary model. Several smaller subcatchments (the remaining 18% of the study catchment)

were defined in the hydrological model to account for local freshwater inputs to the lower reaches

of the Estuary.

5.1.2.2 Catchment delineation and model extents

A Digital Elevation Model (DEM) with a grid resolution of 20 metres by 20 metres was used to

digitise the upstream area draining to the tidal extents of the Bellinger River and Kalang River, and

to the lower estuary / entrance. Two major sub-catchments were delineated for Bellinger River and

Kalang River as shown in Figure 5-1. Smaller local sub-catchments incorporating the area between

the two major sub-catchments and the estuary mouth were also included. The total area of

Bellinger Kalang River catchment (herein referred to as the study catchment) is 1116 km2.

Details of the major sub-catchments are presented in Table 5-1.

Table 5-1 Major Sub-catchment Details

Sub-catchment Main Stream Length (km)

Area (km 2) % Total Area

Bellinger River 76.6 661.0 59.2

Kalang River 45.7 250.9 22.5

Lower Estuary 48.0 203.9 18.3

Total 170.3 1115.8 100



5.1.2.3 Functional units

When creating a Source catchment model, sub-catchments are divided into areas with a common

hydrologic response or behaviour called functional units (FUs), based on various combinations of

land use or cover (e.g. bushland, rural, urban), management, position in landscape (flat, hill slope,

and ridge) and/or hazard.

FUs are used to reflect the different hydrologic responses in the area of interest (Delgado et al.,

2012). Aerial imagery (Bing Maps, 2011) was used to derive a map of FUs for the study catchment.

FUs were broadly classified according to clearance of native bushland and the amount of

impervious surfaces expected within. The following broad categories were identified and adopted in

preparing the Source for Catchments model to account for differing runoff response to rainfall. The

categories include:

• Bushland – Includes areas of uncleared native bushland;

• Rural – Includes areas cleared of bushland / native vegetation but not residential development

areas. Some minor development (rural properties and local roads) expected within; and

• Urban – Includes the higher density residential and commercial development located around

key townships such as Bellingen, Urunga, Mylestom and Repton;

• Wetland – Includes low-lying wetland areas identifiable from aerial imagery such as Urunga

Lagoon, Back Creek and Boggy Creek; and

• Water – Includes the main waterway area of the Bellinger and Kalang Rivers downstream of

Bellingen and Brierfield.

The spatial distribution of the above FUs were mapped in a GIS (refer to Figure 5-2) and used as

input to the Source for Catchments model. The area of each FU within subcatchments was

automatically assigned by the model using the gridded input dataset. A summary of catchment

properties including area and the proportion of the above FUs for each sub-catchment is provided

in Table 5-2.



Figure 5-1 Subcatchment Delineation

Bellingen Shire Estuary Inundation Mapping 59 Estu ary Ecological Modelling


Table 5-2 Sub-catchment Properties

ID Area (km 2) Functional Units

% Bushland

% Rural

% Urban

% Wetland

% Waterway

1 661.0 91.1 8.9 0.0 0.0 0.0

2 10.56 43.7 54.6 0.0 1.7 0.0

3 21.44 47.2 49.9 0.0 0.0 2.9

4 23.93 61.7 37.1 0.0 0.0 1.2

5 42.30 60.8 33.8 4.8 0.0 0.6

6 11.90 13.4 63.6 4.1 9.8 9.1

7 4.58 8.3 70.0 6.1 14.9 0.7

8 5.90 67.6 25.4 5.5 0.1 1.4

9 9.76 4.8 25.8 16.3 31.2 21.9

10 12.28 48.2 40.6 5.0 0.7 5.5

11 11.69 81.1 15.8 0.0 0.0 3.1

12 250.9 93.4 6.6 0.0 0.0 0.0

13 4.57 74.8 21.2 0.0 0.0 4.0

14 3.86 79.5 1.3 3.4 15.8 0.0

15 20.07 99.4 0.1 0.0 0.0 0.5

16 12.88 77.1 22.1 0.0 0.0 0.8

17 8.24 76.3 22.0 0.0 0.0 1.7

Combined 1115.86 85.7 12.8 0.5 0.5 0.5



Figure 5-2 Functional Units Used by the Catchment Model



5.1.2.4 Rainfall-runoff model

The SIMHYD rainfall-runoff model was used to model runoff for all surface types defined in the

model. SIMHYD is a conceptual rainfall-runoff model, which is itself a simplified version of the daily

conceptual rainfall-runoff model, HYDROLOG that was developed in 1972.

The model simplifies the rainfall-runoff processes and requires input of the following variables to

perform the hydrological assessment:

• Rainfall;

• Potential evapotranspiration;

• Catchment parameters (area, % impervious and pervious areas); and

• Impervious and pervious area parameters (rainfall threshold, infiltration rates, field capacity, soil

storage depths and groundwater parameters).

SIMHYD has been widely used in Australia and was applied for generating runoff for the Murray

Darling Basin Sustainable Yields study in 2006-2008 (Delgado et al., 2012). SIMHYD model

parameters are typically derived from calibration of the SIMHYD rainfall-runoff model to streamflow

records if available for a study area. Details of the approach to model calibration are provided in

Section 5.1.2.6.

5.1.2.5 Meteorological data

The SIMHYD rainfall-runoff model estimates daily streamflow from daily rainfall and areal potential

evapotranspiration data (APET). SILO is an enhanced climate database containing Australian

climate data from 1889 (current to yesterday), in a number of ready-to-use formats (QLD

Government, 2013). Source for Catchments utilises SILO meteorological data from data drill

locations to calculate spatially weighted (catchment averaged) rainfall timeseries for each

subcatchment.

For the period between January 1900 and December 2012 (inclusive), the mean annual rainfall

(refer to Figure 5-3) and APET (refer to Figure 5-4) was estimated to be 1685 mm and 1319 mm

respectively. The 112 year data period shown includes several large rainfall events including July

1921, July 1950, February 1954 and February 2001. A summary of the meteorological data used

by the catchment model is provided in Table 5-3.

Table 5-3 Summary of Meteorological Data

Statistic Rainfall (mm)

Areal Potential Evapotranspiration (mm)

Min 0.0 0.3

25%ile 0.1 2.1

Mean 6.1 3.6

Median 1.0 3.4

90%ile 16.1 6.0

Max 416.8 8.9



Figure 5-3 Catchment Average Rainfall used by the Catchment Model

Figure 5-4 Catchment Average APET used by the Catc hment Model

0

50

100

150

200

250

300

350

400

450

Jan-0

0

Sep-0

2

Jun-0

5

Mar-08

Dec-

10

Sep-1

3

Jun-1

6

Mar-19

Nov-

21

Aug-2

4

May-

27

Feb-3

0

Nov-

32

Aug-3

5

Apr-38

Jan-4

1

Oct

-43

Jul-46

Apr-49

Jan-5

2

Oct

-54

Jun-5

7

Mar-60

Dec-

62

Sep-6

5

Jun-6

8

Mar-71

Dec-

73

Aug-7

6

May-

79

Feb-8

2

Nov-

84

Aug-8

7

May-

90

Jan-9

3

Oct

-95

Jul-98

Apr-01

Jan-0

4

Oct

-06

Jul-09

Apr-12

Rai

nfal

l (m

m/d

ay)

0

1

2

3

4

5

6

7

8

9

Jan-0

0

Sep-0

2

Jun-0

5

Mar-08

Dec-

10

Sep-1

3

Jun-1

6

Mar-19

Nov-

21

Aug-2

4

May-2

7

Feb-3

0

Nov-

32

Aug-3

5

Apr-38

Jan-4

1

Oct

-43

Jul-46

Apr-49

Jan-5

2

Oct

-54

Jun-5

7

Mar-60

Dec-

62

Sep-6

5

Jun-6

8

Mar-71

Dec-

73

Aug-7

6

May-7

9

Feb-8

2

Nov-

84

Aug-8

7

May-9

0

Jan-9

3

Oct

-95

Jul-98

Apr-01

Jan-0

4

Oct

-06

Jul-09

Apr-12

AP

ET

(m

m/d

ay)



5.1.2.6 Catchment parameters

Streamflow gauging data at Station 205016 (Bellinger River at Fosters) were available for the

period August 2007 to March 2014. The stream gauge is located approximately 2 km upstream of

Bridge Street providing a record of the observed streamflow at the outlet to Sub-catchment #1 on

the Bellinger River, which is the largest of all 17 sub-catchments.

Sub-catchment #1 is predominately bushland with areas of rural landuse present along the plateau

edge near Dorrigo Mountain and Fernbrook, and cleared floodplain areas along the Bellinger River

including townships of Darkwood, Thora, Gleniffer and Bellingen. The Kalang River Sub-catchment

(#12) is also mostly bushland with some rural land use occurring along the floodplain between

Kalang and Brierfield. Daily streamflow measurements recorded at Gauge 205016 were used to

calibrate catchment parameters for the bushland and rural functional units present within the Sub-

catchment #1. Due to similarities in landuse and topography, catchment parameters derived for

Sub-catchment #1 are expected to be equally applicable to Sub-catchment #12 (the other major

inflow location to the Estuary).

When calibrating continuous rainfall-runoff models such as SIMHYD, it is important to adopt a

calibration period that is representative of a ‘wet period’ where streamflows are typically higher.

Calibration of the rainfall-runoff model to a period of higher flow provides opportunity to capture

more runoff events and hence improves the robustness of the model following calibration. For this

reason, all available streamflow data were utilised for the model calibration, which included several

large rainfall and streamflow events during 2007, 2009 and 2011/12. The calibration period

includes a period of high quality data (i.e. record was continuous with no data gaps) and the

availability of a corresponding rainfall record for the same period. Rainfall and streamflow data

used for calibration of SIMHYD are shown in Figure 5-5 and Figure 5-6 respectively.

Figure 5-5 Daily Rainfall Data (August 2007 – Dece mber 2012)

0

20

40

60

80

100

120

140

160

180

200

Aug

-07

No

v-07

Feb

-08

Jun-

08

Sep

-08

De

c-08

Mar

-09

Jul-0

9

Oct

-09

Jan-

10

Ma

y-10

Aug

-10

No

v-10

Feb

-11

Jun-

11

Sep

-11

De

c-11

Apr

-12

Jul-1

2

Oct

-12

Jan-

13

Rai

nfal

l (m

m/d

ay)



Figure 5-6 Daily Streamflow Data (August 2007 – De cember 2012)

Catchment parameters adopted for bushland and rural functional units in the Bellinger River sub-

catchment are shown in Table 5-4. Rainfall and runoff parameters for the rural functional unit is

based on the non-urban landuse category recommended in the NSW MUSIC Modelling Guidelines

(BMT WBM, 2008) which is suitable for localities with a mean annual rainfall of more than

1000 mm. The catchment parameters for bushland were estimated from calibration of the SIMHYD

model to the observed runoff volume at the sub-catchment outlet. Note: these two functional units

account for 98.5% of the total study catchment area.

Table 5-4 SIMHYD Rainfall-Runoff Parameters for Bel linger River Sub-catchment

Parameter Bushland Rural

Impervious Area

Impervious Threshold (mm) n/a n/a

Pervious Area

Pervious Fraction 1.0 1.0

Soil Moisture Storage Capacity (mm) 350 175

Rainfall Interception Store Capacity (mm) 0.5 0.5

Infiltration Coefficient 260 215

Infiltration Shape 2 2.4

Interflow Coefficient 0.50 0.1

Recharge Coefficient 0.50 0.55

Baseflow Coefficient 0.02 0.1

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

Aug

-07

No

v-07

Feb

-08

Jun-

08

Sep

-08

De

c-08

Mar

-09

Jul-0

9

Oct

-09

Jan-

10

Ma

y-10

Aug

-10

No

v-10

Feb

-11

Jun-

11

Sep

-11

De

c-11

Apr

-12

Jul-1

2

Oct

-12

Jan-

13

Str

eam

flow

(ML/

day)



A plot of the daily runoff volume is provided in Figure 5-7 which shows a strong linear relationship

(R2 = 0.84) between the modelled runoff and observed runoff volume. Timeseries of modelled and

observed runoff volume over the calibration period is shown on Figure 5-8. The calibrated flow

duration curve presented in Figure 5-9 and the timeseries of modelled runoff volume show a good

fit between the frequency of runoff estimated by SIMHYD and the observed streamflow data at the

sub-catchment outlet. The flow duration curve also indicates that the frequency of larger runoff

events modelled by SIMHYD is consistent with the observed streamflow data. Some discrepancy

between the observed and modelled runoff is evident during the smaller more frequent events,

however, this is considered to have minimal impact on the outcomes of the modelling. These

discrepancies are most likely due to limitations of modelling baseflow. SIMHYD assumes that

baseflow from an event contributes instantly to flow at the catchment outlet.

Figure 5-7 Calibrated Daily Runoff Volume (modelle d vs observed)

y = 0.92xR² = 0.84

0

20000

40000

60000

80000

100000

120000

0 20000 40000 60000 80000 100000 120000

Mod

elle

d F

low

(M

L/da

y)

Observed Flow (ML/day)

Run 012

Linear (Run 012)



Figure 5-8 Timeseries of Modelled and Observed Run off Volume

Figure 5-9 Calibrated Flow Duration Curve (2007 – 2012)

1

10

100

1000

10000

100000Jul-07

Oct-07

Jan-08

Apr-08

Jul-08

Oct-08

Jan-09

Apr-09

Jul-09

Oct-09

Jan-10

Apr-10

Jul-10

Sep-10

Dec-10

Mar-11

Jun-11

Sep-11

Dec-11

Mar-12

Jun-12

Sep-12

Dec-12

Flo

w (

ML/

day)

Run 012 Gauged Flow

10

100

1000

10000

100000

0 10 20 30 40 50 60 70 80 90 100

Flo

w (

ML/

day)

Flow Percentile (%)

Gauged Flow

Run 012



Overall, the above results indicate that a robust calibration was achieved for one of the major sub-

catchments contributing to the Bellinger Kalang River Estuary. Estimates of daily runoff volume

provided by the catchment model (refer to Section 5.1.2.6) can therefore be used with confidence

to define freshwater inputs to the estuary model for longer-term simulations of estuarine mixing

under current and projected sea level rise scenarios.

For the lower estuary sub-catchments, three other functional units are used by the catchment

model, namely waterway, wetland and urban accounting for 1.5% of the total study catchment

area. Catchment parameters for these three functional units were defined based on the expected

rainfall-runoff response and professional judgement. Catchment parameters adopted for these

functional units are shown in Table 5-5.

Table 5-5 Additional SIMHYD Rainfall-Runoff Paramet ers for Lower Estuary Sub-catchments

Parameter Waterway Urban Wetland*

Impervious Area

Impervious Threshold (mm) 0 1 1

Pervious Area

Pervious Fraction 0.0 0.75 1

Soil Moisture Storage Capacity (mm) n/a 170 320

Rainfall Interception Store Capacity (mm) n/a 1.5 1.5

Infiltration Coefficient n/a 210 200

Infiltration Shape n/a 4.7 3

Interflow Coefficient n/a 0.1 0.1

Recharge Coefficient n/a 0.50 0.2

Baseflow Coefficient n/a 0.05 0.30

* SIMHYD default values; n/a is not applicable

5.1.3 Estimation of daily Runoff Volume

The calibrated catchment model was used to estimate the daily runoff volume from the study sub-

catchments for the period between 1900 and 2012. Timeseries of the daily runoff volume estimated

at the outlet to the major sub-catchments is shown on Figure 5-10.

The timeseries of daily runoff volume for the Bellinger River sub-catchment was selected for

subsequent data analyses and defining a representative inflow timeseries for estuary modelling.

The approach and justification for the selected inflow period is discussed further in Section 5.1.4.

Bell ingen Shire Estuary Inundation Mapping 68 Estuary Ecological Modelling


Figure 5-10 Timeseries of Daily Runoff Volume (190 0 – 2012)

0

50000

100000

150000

200000

250000

300000

Jan-

00

Apr

-03

Jul-0

6

Nov

-09

Feb

-13

Jun-

16

Sep

-19

Dec

-22

Apr

-26

Jul-2

9

Nov

-32

Feb

-36

Jun-

39

Sep

-42

Dec

-45

Apr

-49

Jul-5

2

Nov

-55

Feb

-59

Jun-

62

Sep

-65

Dec

-68

Apr

-72

Jul-7

5

Nov

-78

Feb

-82

Jun-

85

Sep

-88

Dec

-91

Apr

-95

Jul-9

8

Nov

-01

Feb

-05

Jun-

08

Sep

-11

Run

off V

olum

e (M

L/da

y)

Bellinger River Subcatchment Kalang River Subcatchment Local Subcatchments

Bellingen Shire Estuary Inunda tion Mapping 69 Estuary Ecological Modelling


5.1.4 Selection of a Representative Inflow Timeseries

A box-whisker plot of modelled streamflow for the Bellinger River sub-catchment is provided in

Figure 5-11. The plot shows that streamflow occurs all year round and that there is no clear

seasonality in the modelled estimate of daily runoff volume. Whilst the flow regime of the Bellinger

and Kalang Rivers is not seasonal (i.e. a majority of the annual runoff does not occur over a few

months), there are some months (e.g. December to May) where runoff volume is typically higher

than the other months (e.g. June to November).

Daily runoff volumes estimated by the catchment model show that the minimum daily flow is

greater in the months of March, April and December (i.e. >50 ML/day) than the remainder of the

year (<30 ML/day). The minimum daily runoff volume is least during January and greatest during

March, and the median daily flow is greater during the summer and autumn months (e.g.

December, January, February, March and April) than winter and spring months (e.g. August,

September and October). High runoff volume days (i.e. >1000 ML/day) occur during all months

although the largest runoff volumes (i.e. 200,000 ML/day or more) occur in the months of January,

February and June.

Figure 5-11 Box and Whisker Plot of Monthly Modell ed Flow for the Bellinger River Sub-catchment

Bellingen Shire Estuary Inunda tion Mapping 70 Estuary Ecological Modelling


The flow duration curve of daily modelled streamflow for the Bellinger River sub-catchment is

shown on Figure 5-12. The flow duration curve demonstrates that high flows (i.e. greater than

2300 ML/day) occur infrequently (less than 10% of the time). Similarly, low flows (i.e. less than

125 ML/day) are infrequent, with flows being greater than this 90% of the time.

Figure 5-12 Flow Duration Curve for Bellinger Rive r Sub-catchment (1900-2012)

In defining an appropriate estimate of freshwater inflows to the estuary, a single year was selected

from the long-term timeseries of modelled daily runoff volume (refer to Figure 5-10) that:

• provides a steady inflow to the estuary over the year (i.e. runoff events do not occur in

succession or few months at the beginning, middle or end of the year); and

• is a realistic estimate of streamflow at the tidal limits of the estuary that could be expected

during a below average rainfall year, and without any significant fluvial (flood) events where

flows within the Bellinger and Kalang River would significantly exceed natural channel capacity

and inundate the floodplain thereby masking the potential impact of projected sea level rise on

water levels and salinity in the upper reaches of the estuary.

Using the above criterion, estimates of daily runoff volume for the year 2005 were included in the

estuary model for the assessment of sea level rise impacts on water levels and inundation, and

changes to estuarine salinity. The modelled timeseries of runoff volume for the major sub-

catchments is shown in Figure 5-13.

1

10

100

1000

10000

100000

1000000

0 10 20 30 40 50 60 70 80 90 100

Run

off V

olum

e (M

L/da

y)

Percentile



Figure 5-13 Timeseries of Major Inflows to the Est uary (Jan 2005 to Dec 2005)

0

2000

4000

6000

8000

10000

12000

14000

Jan-

05

Jan-

05

Mar

-05

Apr

-05

May

-05

May

-05

Jun-

05

Jul-0

5

Aug

-05

Sep

-05

Oct

-05

Nov

-05

Dec

-05

Run

off V

olum

e (M

L/da

y)

Bellinger River Subcatchment Kalang River Subcatchment Local Subcatchments



5.2 Development of the Estuary Model

5.2.1 Scope and Objectives

To assess changes to inundation frequency and depth and also salinity, longer-term continuous

modelling of the estuary waterbody was undertaken. This modelling required the development of a

two dimensional estuary model (TUFLOW-FV) to simulate the movement (hydrodynamics) and

mixing (advection-dispersion) between tidal saltwater exchange and freshwater catchment runoff.

The separate catchment model (as described in Section 5.1) was used to model freshwater

contributions to the estuary from upstream sub-catchments which influences the longitudinal

variation of salinity along the Bellinger and Kalang rivers.

Using these two models, inundation extent / depth and salinity is predicted and used as key

indicators for assessing potential ecological impacts arising from future SLR by associating the

modelled changes of water level and salinity with vegetation tolerances and expected consequence

levels (see Section 6).

5.2.2 Model Selection

A two-dimensional hydrodynamic model of the Bellinger-Kalang Estuary was developed using the

modelling software TUFLOW-FV. TUFLOW-FV is a two dimensional finite volume model code that

solves the conservative integral form of the non-linear shallow water equations (NLSWE) (i.e.

assuming that pressure varies hydrostatically with depth), including viscous flux terms and source

terms for Coriolis force, bottom-friction and various surface and volume stresses. The model is

currently fully operational as a 2-dimensional or 3-dimensional NLWSE solver.

The model software is also capable of simulating the advection and dispersion of multiple scalar

constituents (e.g. salinity, temperature) within the model domain. Bed friction is modelled using a

Manning’s roughness formulation and Coriolis force is also included in the model formulation. The

spatial domain (or study area extents) is discretised using contiguous, non-overlapping irregular

triangular and quadrilateral ‘cells’. Advantages of an irregular flexible mesh include:

• The ability to smoothly resolve bathymetric features of varying spatial scales (e.g. channels

adjacent to broad shoaled areas);

• The ability to smoothly and flexibly resolve boundaries such as coastlines; and

• The ability to adjust model resolution to suit the requirements of particular parts of the model

domain without resorting to a ‘nesting’ approach.

The flexible mesh approach has significant benefits when applied to study areas involving complex

coastlines and embayments, varying bathymetries and sharply varying flow and scalar

concentration gradients. TUFLOW-FV presently accommodates a wide variety of boundary

conditions, including water level, flow, wind, wave stress and salinity boundaries some of which are

important for the present study.

The assumption of a well-mixed water body can be adequately represented by the two-dimensional

TUFLOW-FV hydrodynamic model. Three dimensional processes driven by salinity and / or thermal



stratification are not significant issues for this study, even though they might occur from time to time

during or immediately following a significant catchment runoff (flood) event.

Water quality and tidal flushing are influenced by currents generated from a combination of tides

and catchment (fluvial) inflows and the primary drivers influencing tidal inundation and salinity

intrusion throughout the estuary.

5.2.3 Model Geometry and Extent

The model includes the full tidal prism of the estuary up to the tidal limits of the Bellinger River near

Bellingen and the Kalang River near Brierfield. The estuary model also includes the extensive

floodplain storage and low-lying wetland situated along these major rivers we well as Urunga

Lagoon located near the mouth of the estuary.

In defining the model geometry, quadrilateral elements were used to represent the main channels

with a mesh resolution in the order 50 to 100 metre longitudinally with typically 3 to 5 elements

across the channel (i.e. elements 20 m to 40 m wide). Floodplain elements are a mixture of

triangles and quadrilaterals with a typical mesh resolution of 50 metre side length up to an

elevation of 5 m AHD.

Important sub-mesh topographical features (such as road crests, small channels or flow paths and

breakwaters) were defined in the model mesh using model z-line elements.

The geometry (mesh) and extent of the TUFLOW-FV model are shown in Figure 5-14.

5.2.4 Bathymetry

Bathymetric data are required to describe the topography of the waterway over the domain of a

numerical model such as this. Elevation data used by the existing flood model (refer to Section

3.1.1) were used to define the bathymetry of the main waterways and floodplain areas.

Elevation data used by the TUFLOW-FV model are shown in Figure 5-14.

5.2.5 Model Configuration

TUFLOW-FV was configured to account for salinity dynamics in response to river inflow, water

level variations caused by ocean tides and local catchment runoff. The model was used in 2-d

mode (i.e. key parameters were depth averaged). The influence of the Coriolis force was

calculated using latitude of -30.5°S.

TUFLOW-FV has an adaptive time-step algorithm which automatically adjusts the model time-step

to resolve hydrodynamic and advection dispersion processes. Internal and external Courant-

Friedrichs-Lewy (CFL) stability criterion values of 1.5 were adopted which resulted in typical time-

step of between 1 and 2 seconds during the model simulation.

Bed roughness is specified as a Manning’s n roughness, which is standard for many two-

dimensional numerical models. The estuary model is uncalibrated however three broad surface

roughness types, namely main channel, floodplain and offshore were defined. The distribution of

bed roughness (and the Manning’s n values) adopted by the model are shown in Figure 5-15.



Figure 5-14 TUFLOW-FV Model Mesh and Bathymetry



Figure 5-15 TUFLOW-FV Manning's n Distribution



TUFLOW-FV accounts for wetting and drying dynamically based of specified cell depths of 0.001 m

and 0.01 m respectively. The drying value corresponds to a minimum depth below which the cell is

dropped from computations (subject to the status of surrounding cells). The wet value corresponds

to a minimum depth below which cell momentum is set to zero, in order to avoid unrealistic

velocities at very low depths.

Salinity was modelled as a passive transport scalar (i.e. uncoupled from temperature and density

effects). The scalar mixing model adopted was the Elder model which calculates non-isotropic

diffusivity using coefficients of 60 (in the longitudinal direction) and 6 (in the transverse direction). A

global horizontal eddy viscosity coefficient of 0.2 was adopted. Calibration of salinity was not

undertaken for this study and as such the model parameters were selected as being typical for the

study estuary.

5.2.6 Boundary Conditions

The estuary model adopts a downstream water level boundary to represent ocean tide variations.

For this model boundary, ocean tide data measured continuously (15 minutes intervals) at the

nearest gauging site to the study area (Coffs Harbour) was used.

Timeseries of daily runoff volume from the major rivers (Bellinger and Kalang) and local

contributing sub-catchments (15 in total) were specified using the nodestring flow boundary and

cell inflow boundary options available in TUFLOW-FV. The daily runoff volume was distributed

evenly over each model time step by the model software.

5.2.7 Long-term Estuary Modelling Scenarios

The estuary model was used to estimate changes to water level/depth, inundation extents and

salinity caused by SLR over a continuous one year period to account for temporal and spatial

variability of estuarine mixing. The model scenarios investigated by the estuary ecological

modelling are summarised in Table 5-6.

Table 5-6 Long-term Estuary Salinity Modelling Scen arios

Scenario Ocean Tide Condition Catchment Inflow

Basecase Observed tidal gauging records for Coffs Harbour over a continuous one-year period.

Below average annual inflow timeseries estimated using catchment model (see Section 5.1.4).

SLR 0.4 metres Same as Basecase except that downstream ocean tide levels are raised by 0.4 metres.



A continuous one-year period was adopted for the scenario simulations. An additional one month

period was included at the beginning of each simulation to ‘warm-up’ the model and establish



hydrodynamic conditions (e.g. momentum, tidal pumping, water levels and salinity) within the

waterbody. Freshwater flows from the upstream catchments were modelled for a below average

annual runoff year and incorporated in the estuary model as outlined in Section 5.1.4.

5.3 Estuary Modelling Results The result of long-term estuary modelling scenarios is contained in the following sections. A map of

the long sections, chainage markers and reported locations used to obtain the following results is

presented in Figure 5-16.

5.3.1 Long-section Profiles

Long-section profiles are presented for the Bellinger River and Kalang River (Figure 5-17 to Figure

5-20). A series of subplots show the envelope (minimum, 25%ile, median, 75%ile and maximum) of

water level and salinity predicted for the different SLR scenarios 0.0, 0.4, 0.9 and 1.4 m AHD.

A summary table showing the location (chainage along each long section) where median salinity

values of 1, 5, 10, 15, 20 and 30 psu are modelled to occur is provided in Table 5-7. The relative

change between the existing (0 m MSL) scenario and increased MSL scenarios is shown in

brackets.

Table 5-7 Summary of Modelled Salinity Profiles (Me dian Salinity)

Median Salinity (psu)

0 m MSL +0.4 m MSL +0.9 m MSL +1.4 m MSL

BR KR BR KR BR KR BR KR

30 2290 2800 2820 (530)

3310 (510)

3240 (950)

3880 (1080)

3660 (1370)

4610 (1810)

20 3700 3960 4260 (560)

4690 (730)

4750 (1050)

5430 (1470)

5190 (1490)

6550 (2590)

15 4270 4520 4880 (610)

5350 (830)

5350 (1080)

6120 (1600)

5990 (1720)

7390 (2870)

10 4890 5150 5540 (650)

6020 (870)

6320 (1430)

6880 (1730)

7140 (2250)

8380 (3230)

5 5770 6020 6770 (1000)

7010 (990)

7520 (1750)

8040 (2020)

8760 (2990)

9850 (3830)

1 7740 7650 9300 (1560)

8930 (1280)

10390 (2650)

10250 (2600)

11380 (3640)

12300 (4650)

BR – Bellinger River; KR – Kalang River



Key points highlighted by water level profile results:

• Ignoring the influence of high fluvial flow events on upstream water levels, the range in water

level is greatest at the mouth of the estuary where tidal influence is most pronounced. The

maximum water level at the upstream end of the long section profile (CH20000 – CH25000) is

influenced by fluvial flow events from the upstream catchment. A step change in water level is

also shown for this part of the long section profile (most evident for the Kalang River) which is a

consequence of excluding the out of channel (floodplain storage) area in this part of the model

and should be disregarded.

• Between CH2000 and CH20000, the water profile is uniform and sufficiently downstream

(upstream) of the river inflow (tidal inflow) influences. It is this segment of the long section

profiles where the impact of SLR on water level is most significant.

• Comparing between SLR scenarios, the results show that at CH10000 (Bellinger River at

Raleigh and Kalang River near Newry Island), and with 1.4 m of SLR, the median water level of

about 1.45 m AHD would be notably greater (by approximately 0.3 metres) than the maximum

water level expected under existing tidal conditions. Of somewhat more importance, the

minimum water level at that same location with 1.4 m of SLR is 0.65 m AHD, which is 1 metre

higher than the lowest water level modelled for the existing (SLR 0 m) condition. A water level of

this magnitude would only be exceeded about 5% of the time under existing conditions, which

typically occurs during large spring or king tides.

Key points relating to salinity profiles include:

• Under existing (SLR 0 m) conditions, a median salinity of 20 psu occurs on the Kalang River

near the downstream end of Newry Island (CH4000), and on the Bellinger River near the

upstream end of Back Creek (CH3680). A maximum salinity of 5 psu occurs near Fernmount

(CH17000) on the Bellinger River and at CH14000 on the Kalang River.

• For all SLR scenarios, the profile of minimum salinity is controlled by large fluvial flow events

from the upstream catchment, resulting in freshwater conditions along the full length of the two

river systems down to the estuary mouth. The relative position of minimum salinity along the two

rivers is comparable between the different SLR scenarios;

• Of greater interest is the change in the relative position and slope of the salinity profiles between

the different SLR scenarios 0.0, 0.4, 0.9 and 1.4 m AHD. Table 5-7 shows that the ingress of

saltwater is greater along the Kalang River than Bellinger River – this is partly due to the smaller

catchment area and consequently lower river discharge draining along this reach of estuary;

and

• For the Kalang River, a median salinity of 1 psu would be situated 1.3 km, 2.6 km and 4.6 km

further upstream of the existing scenario with increases of 0.4, 0.9 and 1.4 metres to MSL

respectively. Similarly, for the Bellinger River, the median salinity of 1 psu is predicted to

migrate 1.6 km, 2.7 km and 3.6 km upstream of the existing modelled location.



Figure 5-16 Long-term Estuary Modelling Reporting Locations and Long Section Profiles



Figure 5-17 Long Section Profiles of Water Level f or the Bellinger River

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter

Leve

l (m

AH

D)

Chainage (m)

Existing (SLR 0.0 m)Min 75% exceedance 50% exceedance 25% exceedance Max

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter

Leve

l (m

AH

D)

Chainage (m)

SLR 0.4 mMin 75% exceedance 50% exceedance 25% exceedance Max

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

HA

D)

Chainage (m)


-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

AH

D)

Chainage (m)




Figure 5-18 Long Section Profiles of Salinity for the Bellinger River

0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


Bellinge n Shire Estuary Inundation Mapping 82 Estuary Ecological Modelling


Figure 5-19 Long Section Profiles of Water Level for the Kalang River

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

AH

D)

Chainage (m)


-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

AH

D)

Chainage (m)


-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

AH

D)

Chainage (m)


-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0500010000150002000025000

Wa

ter L

eve

l (m

AH

D)

Chainage (m)




Figure 5-20 Long Section Profiles of Salinity for the Kalang River

0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)


0

5

10

15

20

25

30

35

02000400060008000100001200014000160001800020000

Sa

linity

(psu

)

Chainage (m)




5.3.2 Cumulative Frequency Curves

Cumulative frequency curves of water depth and salinity are presented at key reporting locations,

namely Site A to Site F as shown in Figure 5-16. The reporting locations broadly correspond to

ecologically sensitive compartments in the estuary where mangroves, saltmarsh, EECs and other

significant vegetation communities typically occur. The reporting locations also correspond to sites

selected for ecological monitoring as described in Section 7.6.

For each reporting site, cumulative frequency curves are presented for the different SLR scenarios

0.0, 0.4, 0.9 and 1.4 m AHD. The cumulative frequency curves show the range and distribution of

water depth (refer to Figure 5-21) and salinity (refer to Figure 5-22) predicted by the model at each

reporting location over the one-year simulation period.

A summary of the cumulative frequency histogram charts (median water depth and salinity) is

provided below in Table 5-8.

Table 5-8 Summary of Cumulative Frequency Results

Reporting Site SLR Scenario

0 m MSL +0.4 m MSL +0.9 m MSL +1.4 m MSL

A Water depth (m) 0 0.36 0.85 1.36

Salinity (psu) 6.2 8.3 11.8 22.0

B Water depth (m) 1.2 1.3 1.3 1.6

Salinity (psu) 29.1 32.7 33.8 34.3

C Water depth (m) 1.3 1.4 1.8 2.3

Salinity (psu) 23.7 27.6 31.0 31.7

D Water depth (m) 0 0.15 0.4 0.8

Salinity (psu) 0 7.8 19.2 25.6

E Water depth (m) 1.0 1.3 1.8 2.3

Salinity (psu) 32.7 32.5 31.0 29.4

F Water depth (m) 0.3 0.3 0.3 0.7

Salinity (psu) 34.5 34.6 33.7 33.4

The estuary modelling results demonstrate that SLR will clearly alter the range and frequency of

inundation and salinity experienced at a range of sites in the estuary. Both inundation and salinity

are important indicators of potential consequences of SLR. Significant changes to the depth of

inundation and salinity will have important implications for the adaptability or susceptibility of

existing vegetation communities to such change. For example, vegetation with a low tolerance for

increased inundation and/ or salinity will be most affected by SLR and the consequence of change

is likely to be high. Even greater consequences may arise for important vegetation communities

such as saltmarsh and swamp oak which could be pressured by mangrove invasion on the

seaward side and coastal development on the landward side. In view of this, a broad assessment

of ecological impacts is provided in Section 6.5.1.



Figure 5-21 Cumulative Frequency Curves (Water Dep th)



Figure 5-22 Cumulative Frequency Curves (Salinity)

Bellingen Shire Estuary Inundation Mapping 87 Interpretation and Risk Based Assessment of the Eco logical Impacts


6 Interpretation and Risk Based Assessment of the Ecological Impacts

The following describes the habitat and conservation value of ecological communities in aquatic,

riparian and floodplain habitats within areas predicted to be directly affected as a consequence of

the SLR scenarios described above. Potential impacts to habitats, communities and species are

considered in the context of predicted changes to inundation levels, inundation frequency and long

term salinity patterns.

6.1 Overview This ecological assessment is based on the following scope of works:

• Review inundation extent mapping generated by the modelling;

• Based on available data provided by Council, generate maps of vegetation communities,

habitats and other features of biodiversity significance covering areas within and adjacent to the

predicted inundation areas;

• Review existing information to define known or likely high value natural assets within and

adjacent to the predicted inundation area;

• Assess the likely biodiversity consequences of SLR on high value natural assets;

• Conduct a qualitative risk assessment on the impacts of SLR on freshwater aquifer levels,

freshwater wetlands and any likely saltwater intrusions or impacts on aquifer dependent

ecological communities;

• Suggest mitigation options to reduce the impact of SLR on important high value natural assets;

and

• Identify monitoring sites for ongoing assessment of geomorphic response and ecological

community change to SLR.

6.2 Methodology

6.2.1 Study Area

The study area was selected based on the estimated extent of SLR impacts as modelled and

described in preceding sections. This area is shown in Figure 6-1.

6.2.2 Mapping of High Value Natural Assets

The ecological investigations included a comprehensive desktop analysis of the flora and fauna

values with the study area. Information used in this assessment includes aerial photography

(Google 2014), vegetation mapping, searches of public databases, and reports (principally Hawkins

and Mathews, 2006; Telfer and Cohen, 2010).

Bellingen Shire Estuary Inundation Mapping 88 Interpretation and Risk Based Assessment of the Eco logical Imp acts


Figure 6-1 High Value Natural Assets of the Bellin ger and Kalang Rivers, Floodplains and Estuaries



These information sources were used to derive a list of species, communities, habitats and other

features of high biodiversity significance within areas predicted to be inundated by SLR. Whilst all

native vegetation and habitats within the study area has ecological value, habitats of highest

conservation value, referred to as high value natural assets, support species or communities listed

under the Threatened Species Conservation Act 1995 (TSC Act), Environment Protection and

Biodiversity Conservation Act 1999 (EPBC Act), Fisheries Management Act 1994, and/or are

features of high biodiversity value protected under State Environmental Planning Policies. High

value natural assets types and information sources are listed in Table 6-1.

Table 6-1 High value natural asset types and data s ources

High value natural asset type

Legislation Data Sources

Threatened and migratory species and endangered or vulnerable ecological communities listed by the Commonwealth

Environment and Protection Conservation Act 1999

• EPBC database search tool (Department of Sustainability, Environment, Population and Communities, DSEWPC 2014)

• Hawkins and Mathews (2006)

• Bellingen Vegetation Map (March 2014)

Endangered Ecological Communities (EEC’S)

Threatened Species Conservation Act 1995

• Atlas of NSW Wildlife: Office of Environment and Heritage’s database of flora and fauna records

• Hawkins and Mathews (2006)

State listed threatened species

Threatened Species Conservation Act 1995


State listed protected aquatic species and habitats

Fisheries Management Act 1994


Features protected under State Environmental Planning Policies (SEPP)

SEPP14 Wetlands, SEPP26 Littoral Rainforest

• Planning New South Wales

Protected areas for conservation purposes

Wilderness Act 1987

Marine Parks Act 1997

• NPWS and Forests NSW estate, including areas identified as Wilderness for the purposes of the Wilderness Act 1987 / Areas identified under the Marine Parks Act 1997 and areas identified as Aquatic Reserves

Critical habitat • OEH register of critical habitat in NSW website

Significant wetlands • Directory of Important Wetlands based on that used by the Ramsar Convention in describing Wetlands of International Importance http://www.environment.gov.au/water/publications/environmental/wetlands/ramsar.html

Other habitats of high biodiversity and/or conservation significance such as riparian vegetation and beach habitat.

• Aerial imagery



Spatial data describing the distribution, extent and/or location of high value natural assets within

and adjacent to the predicted SLR inundation area were integrated into a GIS using MapInfo

software package (Version 12).

6.2.3 Biodiversity Consequences of SLR

The likely biodiversity consequences of SLR on high value natural assets were assessed based on

a review of information on known or likely ecological sensitivities to SLR related threats (i.e. altered

hydrology and salinity) and the hydrodynamic and salinity simulations. This assessment focussed

on describing implications to four 'currencies' defined in the Garnaut Climate Change Review

(species abundances, invasive species, ecosystem processes and services, and unanticipated

changes), particularly:

• Landward retreat of coastal wetlands;

• Loss of freshwater wetlands, saltmarsh and their resident species; and

• Flow-on effects to aquatic ecosystems and their functions.

The potential impacts of SLR on freshwater aquifer levels, freshwater wetlands and any likely

saltwater intrusions or impacts on aquifer dependent ecological communities was qualitatively

assessed.

6.2.4 Risk Assessment

A risk assessment was used to identify specific ecological communities and locations most at risk

from impacts of changes to inundation and salinity regime (see Section 4).

6.2.5 Monitoring Sites

Based on the available data and a ground truthing exercise, sites were identified for ongoing

monitoring of geomorphic response and ecological community change. Site selection was based

on several criteria including:

• representative of habitats predicted to be affected by SLR;

• contain high natural value assets; and

• easily accessible.

6.2.6 Assumptions and Limitations

Limitations associated with this assessment are largely a result of the reliance on publicly available

data. Some of the mapping utilised has been developed through remote sensing and the analysis

of aerial photography, which is generally associated with some degree of error due to the scale of

the images available and their interpretation. Other records (e.g. significant species) are reliant on

the identification skills of the surveyor and may be of variable quality.

It should be noted that absence of species or ecological community records does not unequivocally

determine that the species or community does not occur or utilise the site. For example, Coastal

Saltmarsh and Swamp Oak Forest communities often occur in patches <2 ha and in linear patches



<10 metres in width. This is generally too small to map at a local (LGA wide) scale and as a result

these communities may be underrepresented in the available mapping.

6.3 Habitats and Landform of the Study Area The composition and distribution of habitats in the study area is determined by geology and

landform, hydrology, water quality and land uses. The estuarine deposits in the lower and mid

reaches within and adjacent to the tidal front support mangroves, saltmarsh and swamp oak

communities. Seagrasses occur in the shallow waters of the lower estuarine reaches. On the

floodplain, native remnant and regenerating vegetation communities are restricted to narrow or

isolated copses on lands unsuitable for agriculture i.e. prone to flooding or too steep for cultivation.

Floodplain habitats typically comprise freshwater-dominated communities including open water and

broad-leaved paperbark wetlands prone to regular inundation and waterlogging with mixed

sclerophyll communities on higher ground. Pockets of closed rainforest occur on the coastal plains,

footslopes and foothills in the upper reaches of the study area, with lowland rainforest occupying

the riverine corridors and alluvial flats.

The riparian corridor along the length of the study area is generally 0-10 metres in width and whilst

native riverine species dominate, weeds are also prevalent (Bellingen Shire Council, 2011). The

sand dunes and plains on the coast support a mix of grasslands, heath and open woodlands with

wetlands dominating the low-lying swales. Littoral rainforest occurs in sheltered habitats on the

sand dunes.

The following section describes the general geomorphic and habitat features of the Bellinger and

Kalang River reaches and Urunga Lagoon.

6.3.1 The Bellinger River - Upper Estuary

The Bellinger River Upper Estuary is a fluvially dominated reach extending from the tidal limit at

Bellingen downstream to Fernmount (Telfer and Cohen, 2010). The floodplain has a variable

topography and is generally 4 to 7 metres above mean tide level (Telfer and Cohen, 2010). The

riparian corridor, which lies adjacent to agricultural lands, is generally less than 10 metres in width

and highly fragmented. Whilst native riverine species dominate weeds are abundant (Bellingen

Shire Council, 2011). The adjacent floodplains have also been extensively cleared but areas of

Freshwater Wetland remain.

6.3.2 The Bellinger River - Mid Estuary

The Bellinger River - Mid Estuary is fluvially dominated and has variable floodplain topography

generally 2.5 to 4 metres above mean tide level (Telfer and Cohen, 2010). The riparian corridor is

in a similar condition to the upper reaches in that it has been extensively cleared and modified and

is bounded by agricultural land uses (Bellingen Shire Council, 2011). Mangroves occur as a narrow

littoral fringe.

The adjacent floodplains have also been extensively cleared for agriculture. The mid-estuary

floodplains, which are more prone to tidal influence than the upper reaches, support a mix of EEC’s

including Freshwater Wetlands and Swamp Sclerophyll Forest on the floodplain and Swamp Oak

Forest and Coastal Saltmarsh in tidally inundated areas.



6.3.3 The Bellinger River - Lower Estuary

The Bellinger River - Lower Estuary exhibits a pronounced marine influence whilst still exhibiting a

fluvial form (Telfer and Cohen, 2010). Floodplains average 1.5 to 2.0 metres above mean tide level

(Telfer and Cohen, 2010). The riparian corridor is in a similar condition to the upper and mid

reaches in that it has been extensively cleared and modified and is bounded by agricultural land

uses (Bellingen Shire Council, 2011). The adjacent floodplains have also been extensively cleared

for agriculture but support isolated patches of Freshwater Wetlands, Lowland Rainforest (restricted

to Tuckers Island), Swamp Oak Forest and Coastal Saltmarsh. Mangroves occur as a narrow

littoral fringe.

6.3.4 The Kalang River - Upper Estuary

The far upstream fluvially dominated reach on the Kalang River exhibits variable floodplain

topography with floodplains approximately 4 m above mean tide level (Telfer and Cohen, 2010).

The riparian corridor which lies adjacent to agricultural land uses has been extensively cleared and

is generally less than 10 metres in width (Bellingen Shire Council, 2011). Whilst native riverine

species dominate weeds are prevalent (Bellingen Shire Council, 2011). Narrow fringes of Lowland

Rainforest dominate several reaches of the riparian corridor along the main channel and tributaries.

The adjacent floodplains have also been extensively cleared but Freshwater Wetlands, Swamp

Sclerophyll Forest and Lowland Rainforest remain.

6.3.5 The Kalang River Mid-Estuary

The Kalang River Mid-Estuary exhibits a pronounced marine influence whilst still exhibiting a fluvial

form (Telfer and Cohen, 2010). The floodplains have low topography averaging 2 to 3 metres

above mean tide level (Telfer and Cohen, 2010). The majority of the upstream riparian corridor is in

good condition and lies within State Forest. Narrow riparian fringes of Lowland Rainforest occur in

the upper reaches adjacent to agricultural land. The riparian corridor in the downstream section of

this reach is generally in poor condition, averaging less than 10 metres in width (Bellingen Shire

Council, 2011), and lies adjacent to agricultural land uses. Narrow riparian fringes of Swamp

Sclerophyll Forest wetland and Swamp Oak Forest woodland dominate. The floodplains adjacent

to the upper reaches are associated with agricultural lands and have been extensively cleared but

Freshwater Wetlands and Swamp Sclerophyll Forest remain. The floodplains of the lower reaches

are also associated with agricultural lands but are more tidally influenced and Swamp Oak Forest,

Coastal Saltmarsh and Freshwater Wetland have been retained.

6.3.6 The Kalang River - Lower Estuary

The Kalang River Lower Estuary includes the north and south branches of Newry Island which

represent the fluvial transition zone (Telfer and Cohen, 2010). The riparian corridor has been

extensively cleared and is generally less than 10 metres in width (Bellingen Shire Council, 2011),

but narrow fringes of discontinuous Swamp Oak Forest, Coastal Saltmarsh and Swamp Sclerophyll

Forest wetland are present. The low floodplains (averaging 1 to 2 metres above mean tide level) on

Newry Island and the adjacent mainland have also been extensively cleared for agriculture and

residential development but areas of Freshwater Wetlands, Coastal Saltmarsh and Swamp Oak

Forest are present.



6.3.7 The Kalang River Marine Tidal Delta and Urunga Lagoon

The Kalang River Marine Tidal Delta and Urunga Lagoon include the marine-tidal zone (Telfer and

Cohen, 2010). Floodplain height is only 1 to 1.5 metres above mean tide level (Telfer and Cohen,

2010). The riparian corridor in the lower reaches is dominated by mangroves. The riparian corridor

in the upper reaches has been extensively cleared and is generally less than 10 metres in width

(Bellingen Shire Council, 2011). With the exception of Urunga Island and adjacent to Urunga

Lagoon, most of the floodplain has been extensively cleared for agriculture and residential

development with small, isolated copses of mangroves, Swamp Oak Forest, Coastal Saltmarsh

and Swamp Sclerophyll Forest. Sand masses to the east of Urunga Lagoon support a complex of

EEC’s.

6.4 High Value Natural Assets The study area supports the following high value natural assets susceptible to SLR as indicated on

Figure 6-1 and described in detail in the following sections:

• Mangroves and seagrass: protected under the Fisheries Management Act 1994;

• Coastal Saltmarsh: listed as an Endangered Ecological Community (EEC) under the

Threatened Species Conservation Act 1995 (TSC) and Vulnerable under the Environment

Protection and Conservation Act 1999 (EPBC);

• Swamp Oak Floodplain Forest: listed as an EEC under the TSC;

• Freshwater Wetlands on Coastal Floodplains: listed as an EEC under the TSC;

• Swamp Sclerophyll Forest on Coastal Floodplains: listed as an EEC under the TSC;

• Lowland Rainforest: listed as an EEC under the TSC and Critically Endangered under the

EPBC;

• Lowland Rainforest on Floodplain: listed as an EEC under the TSC and Critically Endangered

under the EPBC. Note this community is distinguished from Lowland Rainforest in that it

generally occupies riverine corridors and alluvial flats;

• Littoral Rainforest: listed as an EEC under the TSC and Critically Endangered under the EPBC.

Includes SEPP 26 Littoral Rainforests;

• Subtropical Coastal Floodplain Forest: listed as an EEC under the TSC;

• Themeda Grassland on Seacliffs and Coastal Headlands: listed as an EEC under the TSC;

• SEPP 14 Wetlands protected under the State Environmental Planning Policy 14;

• Riparian Corridor: Some areas support EEC’s but all riparian vegetation has ecological value.

• Threatened Species: Appendix D contains a detailed list of threatened species recorded from

the region and their associated habitat types within the study area.



6.4.1 Seagrass

Seagrass beds occur in the shallow waters of Back Creek, Urunga Lagoon, and Bellinger River up

to McGearys Island and around Urunga Island and Newry Island. Consistent with other estuaries

on the NSW North Coast, seagrass in the study area is dominated by Zostera muelleri (BMT WBM,

2007). Minor fringes of Halophila ovalis also occur in Urunga Lagoon (BMT WBM, 2007).

Seagrasses provide food and shelter for many species of fish and invertebrates including those of

economic significance and are protected under the Fisheries Management Act 1994. All areas of

seagrass in the study area have a high conservation value.

6.4.2 Mangroves

Mangroves occur in low energy, inter-tidal sedimentary environments. Consistent with other

estuaries on the NSW North Coast, mangroves of the Bellinger / Kalang River estuary include

mono-specific and mixed stands of Avicennia marina (Grey Mangrove) and Aegiceras corniculatum

(River Mangrove) (BMT WBM, 2007).

Extensive clearing of wetland vegetation, drainage, flood gating and associated loss of habitat and

connectivity has resulted in significant losses of estuarine wetlands within the Bellinger River

catchment. The largest remaining mangrove forests within the Bellinger River catchment occur at

Back Creek and its backwaters. Within the Kalang River catchment, several small patches of

estuarine wetlands occur including Urunga Lagoon and near Newry Island. In the upper estuary,

extensive mangroves occur in the sheltered brackish waters of lower Picket Hill Creek adjacent to

Newry State Forest.

Mangroves provide habitat for species of fisheries value and conservation significance, and provide

a range of ecosystem services including bank stabilisation and nutrient cycling. Mangroves are

protected under the Fisheries Management Act 1994.

6.4.3 Coastal Saltmarsh

Saltmarsh provides habitat for species of fisheries value and conservation significance (e.g.

migratory waders), and is protected under the Fisheries Management Act 1994. Coastal Saltmarsh

in northern NSW is protected as an Endangered Ecological Community under the Threatened

Species Conservation Act 1995 (DEH, 2014a) and Subtropical and Temperate Coastal Saltmarsh

is listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999.

The following habitats are excluded from the EPBC listed coastal saltmarsh:

• saltmarsh occurring on inland saline soils with no tidal connection;

• isolated patches of saltmarsh < 0.1 ha;

• patches or areas of saltmarsh that contain > 50% weeds (i.e. patches must be dominated by

native saltmarsh plant species to be the ecological community);

• patches of saltmarsh (possibly senescent) within the coastal margin that are disconnected

(either naturally or artificially) from a tidal regime but were once connected. However, should the

patch be reconnected to the tidal regime (e.g. via removal of an artificial barrier, or constructing

Bellingen Shire Estuary Inundation Mapping 95 Interpretation and Risk Based Assessment of th e Ecological Impacts


a pipeline under a roadway), then the patch can become part of the ecological community (i.e. if

it meets other key diagnostics and condition thresholds).

Saltmarsh occurs as isolated and discontinuous patches along Back Creek, Urunga Island and

Newry Island. Urunga Lagoon supports the largest contiguous saltmarsh community within the

study area.

Consistent with other estuaries on the NSW North Coast, saltmarsh in the study area is dominated

by a groundcover of Sporobolus virginicus, Suaeda australis, Juncus kraussii, Halosarcia indica,

Isolepis nodosa and Tetragonia tetragonoides with isolated mangrove canopy shrubs and trees

(BMT WBM, 2007).

6.4.4 Swamp Oak Forest

This community type generally consisted of mono-specific stands of Casuarina glauca but may

contain Melaleuca quinquenervia (broad-leaved paperbark) as a sub-dominant or co-dominant.

They typically occur on very poorly drained sites in adjacent to tidal waters.

The largest areas of swamp oak within the study area occur landward of the mangrove fringe of

Back Creek and its backwaters, Urunga Lagoon, Newry Island and the upper estuary waters of

lower Picket Hill Creek adjacent to Newry State Forest.

Swamp Oak floodplain forest of the NSW North Coast is listed as an Endangered Ecological

Community under the TSC Act (DEH, 2014b).

6.4.5 Freshwater Wetlands

These communities typically occur in association with Melaleuca or sclerophyll swamps and are

dominated by sedges and rushes with sparse trees and shrubs. These wetland communities may

provide habitat for significant species such as waterwheel plant (Aldrovanda vesiculosa), Green

and Golden Bell Frog (Litorea aurea), Great Egret (Ardea alba), Intermediate Egret (Ardea

intermedia), Little Egret (Ardea garzetta), Black-necked Stork (Ephippiorhynchus asiaticus), Royal

Spoonbill (Platalea regia), Japanese Snipe (Gallinago hardwickii) and Black-winged Stilt

(Himantopus himantopus).

Freshwater wetlands on coastal floodplains of the NSW North Coast are listed as an Endangered

Ecological Community under the TSC Act (DEH, 2014c).

6.4.6 Swamp Sclerophyll Forest

These communities occur on very poorly drained sites and are generally dominated by Melaleuca

quinquenervia. Other species can include Melaleuca styphelioides, M. linariifolia, M. nodosa, M.

sieberi, Casuarina glauca, Eucalyptus spp and Corymbia spp. The lower stratum is generally

absent or sparse and comprised of sedges and wet heath species with occasional rainforest

elements.

Agricultural activities across the floodplains of the study area have resulted in extensive clearing of

wetland vegetation and drainage of the floodplain however narrow copses of these communities

occur throughout the study area.



Swamp Sclerophyll Forest provides potential habitat for the endangered swamp orchids Phaius

australis and P. tancarvilleae. In addition, they provide habitat for threatened fauna species such as

Grey-headed Flying Fox (Pteropus poliocephalus), Yellow-bellied Glider (Petaurus australis),

Regent Honeyeater (Xanthomyza phrygia), Swift Parrot (Lathamus discolor), Osprey (Pandion

haliaetus), Australasian Bittern (Botaurus poiciloptilus), Large-footed myotis (Myotis adversus),

Litoria olongburensis and Wallum Froglet (Crinia tinnula).

Swamp sclerophyll forest on coastal floodplains of the NSW North Coast is listed as an

Endangered Ecological Community under the TSC Act (DEH, 2014d).

6.4.7 Rainforests

Three rainforest communities, typified by a closed canopy, occur within the study area:

• Lowland Rainforest is the most widespread rainforest type in the study area. It is generally

associated with basalt and sedimentary rocks on the coastal plains, footslopes and foothills in

the upper reaches of the study area;

• Lowland Rainforest on Floodplain is distinguished from Lowland Rainforest in that it generally

occupies riverine corridors and alluvial flats of the study area in the mid to upper reaches of the

Kalang River; and

• Littoral Rainforest occurs on sand dunes of the study area east of Urunga Lagoon. Some

Littoral Rainforest remnants are protected under State Environmental Planning Policy 26 (SEPP

26).

All these rainforest communities are listed as EEC’s under the TSC (DEH, 2014e,f,g) and Critically

Endangered under the EPBC. All potentially support a number of threatened species such as

Acronychia littoralis (Scented Acronychia), Cryptocarya foetida (Stinking Laurel), Hicksbeachia

pinnatifolia (Red Bopple Nut), Fontainea oraria (Coast Fontainea), Ninox strenua (Powerful Owl),

Dasyurus maculatus (Spotted-tailed Quoll) and Kerivoula papuensis (Golden-tipped Bat).

6.4.8 Subtropical Coastal Floodplain Forest

These communities occur in the south-east of the study area south of Urunga Lagoon and are

associated with clay-loams and sandy loams, on periodically inundated alluvial flats, drainage lines

and river terraces on coastal floodplains. The structure of the community may vary from tall open

forests to woodlands and the most widespread trees include Eucalyptus tereticornis (forest red

gum), E. siderophloia (grey ironbark), Corymbia intermedia (pink bloodwood) and Lophostemon

suaveolens (swamp turpentine). This community may provide habitat for a broad range of

significant fauna such as Glossy Black Cockatoo (Calyptorhynchus lathami lathami), Squirrel Glider

(Petaurus norfolcensis) and Koala (Phascolarctos cinereus).

Subtropical Coastal Floodplain Forest is listed as an EEC under the TSC (DEH, 2004h).

6.4.9 Themeda Grassland on Seacliffs and Coastal Headlands

This community is listed as an EEC under the TSC (DEH, 2004i). Themeda australis is the

dominant species in this community but emergent shrubs may also occur. Individual stands of the

community are often very small and overall the community has a highly restricted geographic



distribution comprising small, but widely scattered patches. This community lies to the south of the

study area restricted to an isolated patch less than one hectare in area and is not predicted to be

impacted by the SLR scenarios, as such this community is not considered further.

6.4.10 Riparian Corridor

The majority of the riparian corridor in the study area lies adjacent to agricultural land uses and has

been extensively cleared. It generally occurs as a narrow fringe 0 to 10 metres in width and whilst

native riverine species dominate weeds are prevalent (Bellingen Shire Council, 2011). In addition to

the presence of EEC’s, notably Swamp Oak Forest in the mid to lower reaches and Lowland

Rainforest on Floodplain in the upper reaches, riparian corridors provide important functions such

as water quality control and provide habitat for threatened species such as Koala. All riparian

vegetation in the study area has high conservation value.

6.4.11 Groundwater Dependant Ecosystems

Groundwater dependent vegetation does not rely on the surface expression of water but instead

depends on the subsurface presence of groundwater (Kuginis et al. 2012). Although rainfall is the

dominant source of water for most wetlands groundwater plays a minor to essential role in all

Australian wetlands (Hatton and Evans, 1998). Some wetlands are obligate groundwater

dependant ecosystems (GDE’s) which are dependant on groundwater, for example, swamp

sclerophyll communities, wet heathlands and sedgelands growing in swales and swamps and

subject to shallow water table levels (Kuginis et al. 2012). Other communities are facultative GDEs

which may only depend on groundwater under dry conditions, for example dry heathland on beach

ridges and dunes subject to deeper water table levels (Kuginis et al. 2012).

Broadly within the study area, vegetation and wetlands located within coastal sand aquifers are

likely to be dependent on groundwater whilst the importance of groundwater to floodplain

vegetation will depend on the nature of underlying soils and aquifer (Kuginis et al. 2012). The tidal

wetlands would depend on the flux of groundwater either directly or on groundwater fed discharge

at the mouths of the Bellinger and Kalang Rivers. The importance of groundwater discharge to the

ecosystems within the study area is poorly understood and the extent of groundwater dependency

is largely unknown. However, based on the Risk Assessment Guidelines for GDE’s in NSW

(Kuginis et al. 2012), the study area supports the following potential GDE’s:

• Non-Tidal Freshwater Wetlands: swamp forests; freshwater wetlands; freshwater lagoons;

sedgelands; swamp heath; shrub swamps;

• Tidal Wetlands: mangroves; saltmarsh; seagrass; inter-tidal sand and mudflats; tidal lagoons;

• Floodplain Communities: woodlands and open forests; rainforest;

• Coastal Dunes: sclerophyll forests/woodlands/scrubs; heath; littoral rainforest;

• Sedimentary Habitats: sand beaches; and

• Aquatic habitats: freshwater streams and rivers.

Although it is assumed many of these communities depend on groundwater, the nature of

dependency is largely unknown.



Based on Kuginis et al. (2012), to be classed a GDE of high ecological value within the Northern

Rivers of NSW the potential GDE (or part thereof) must:

• Occur within a protected area (National Park / Marine Reserve / SEPP /DIWS /Ramsar);

• Be identified as a rainforest community;

• Support threatened/endangered species or communities;

• Be identified as Critical Habitat or Key Habitat;

• Be a high conservation value area within a Regional Conservation Plan;

• Be identified as an area of importance to biodiversity within the Northern Rivers Regional

Biodiversity Management Plan.

Figure 6-2 to Figure 6-4 show the areas of high ecological value GDE’s identified on the coastal

sands and alluvial plains of the study area (Kuginis et al., 2012). Based on the available mapping

the following EEC’s recorded in the study area are classed as GDE’s: Littoral Rainforest, Lowland

Rainforest, Swamp Oak Floodplain Forest, Swamp Sclerophyll Forest on Coastal Floodplains, Sub-

tropical Coastal Floodplain Forest, Coastal Saltmarsh and Freshwater Wetlands on Coastal

Floodplains (Kuginis et al.2012).

6.4.12 State Environmental Planning Policies

The aim of State Environmental Planning Policy 14 (SEPP 14) – Coastal Wetland, is to ensure that

coastal wetlands are preserved and protected. Approximately 260 ha of SEPP 14 wetlands occur

on the lower floodplain of the estuary. The major occurrences of SEPP 14 Wetlands in the estuary

include Urunga Lagoon, south of Urunga, west of Newry Island, Back Creek and Urunga Island.

Some Littoral Rainforest remnants east of Urunga Lagoon are protected under State Environmental

Planning Policy 26 (SEPP 26), the aim of which is to ensure that littoral rainforests are preserved

and protected.

Bellingen Shire Estuary Inundation Mapping 99 Interpretation and Ris k Based Assessment of the Ecological Impacts


Figure 6-2 High Ecological Values GDE’s Bellinger- Nambucca Coastal Sands



Figure 6-3 High Ecological Values GDE’s Coastal Be llinger Alluvial

Figure 6-4 High Ecological Values GDE’s Coastal Ka lang Alluvial



6.5 Biodiversity Consequences of Sea Level Rise This section describes the potential implications of SLR on High Value Natural Assets based on

degree of saline intrusion and inundation only. This report does not consider the complex

interactions between ecological, geomorphological and biogeochemical processes that are likely to

occur.

6.5.1 Broad SLR Ecological Impacts

The most profound effect of climate change on estuarine habitats will probably be SLR (Lovelock

and Ellison 2007, Gilman et al. 2008, BMT WBM 2011) and the biodiversity consequences of such

an effect are described below. It is important to note that SLR represents only one component of

climate change and is linked to numerous other interacting climate change processes. Various

secondary impacts may also arise such as changes in ecosystem processes resulting from altered

fluvial flow regimes, loss of habitat connectivity, physical disturbance to habitats and species

resulting from increasing storms. It is beyond the scope of this study to present these processes in

detail.

The biodiversity consequences due to SLR can be grouped into four key ‘currencies’ as follows

(based on MacNally et al. 2008):

• Species abundances: SLR may provide favourable conditions in new areas for some species,

notably mangroves, and declines in the extent of suitable habitat for others that are intolerant of

the new environmental conditions and unable to migrate to suitable habitat (e.g. coastal

saltmarsh).

• Invasive species: Changes in environmental conditions may increase opportunities for invasive

or disturbance-dependant species, both native and exotic, to the detriment of native

communities (e.g. Phragmites invasion of coastal saltmarsh).

• Ecosystem processes and services: Trophic function and ecosystem integrity is likely to be

affected both directly, and as a secondary flow-on through changes to habitats, species

distribution and abundance, connectivity and biogeochemical processes.

• Unanticipated changes: There is a clear need for better information on the physical

characteristics of the landscape, the functioning of wetland ecosystems and the resilience of

individual species to SLR in order to make more accurate predictions. However, even with

further information, there will undoubtedly be a range of unanticipated changes that cannot be

predicted given the complexity and stochastic nature of wetland ecosystems.

At the habitat scale, SLR is expected to result in coastal inundation, increased erosion and saline

intrusion with resulting transitions in wetland communities and species composition (Trail et al.,

2011). SLR in combination with associated shoreline erosion and saltwater intrusion will result in

local losses, which may be offset by potential gains and produce an overall shift in estuarine and

freshwater wetlands (Millennium Assessment 2005). However, determining the vulnerability of

habitats to SLR and quantifying these impacts is complex and depends in part on biophysical

aspects including coastal dynamics, hydrology, water quality, saline intrusion and sedimentation. In

addition, these habitat responses will be sensitive to land uses which may influence the ability of

habitats to colonise and migrate in response to SLR.

Bellingen Shire Estuary Inundation Mapping 102 Interpretation and Risk Based Assessment of the Eco logical Imp acts


Based on the SLR modelling and available habitat mapping, it is predicted that SLR will impact on

the low floodplains and littoral fringe of the upper, mid and lower reaches of the Bellinger and

Kalang Rivers and the full extent of Urunga Lagoon. This is predicted to impact on a variety of High

Value Natural Assets as shown in Figure 6-5 and outlined below in the following sections.

6.5.1.1 Seagrass

The critical factors for seagrass growth are light, temperature, carbon dioxide, nutrients and

suitable substrate (Connolly, 2012). In particular, water depth, which controls the ambient light

climate, is a key control on the distribution and extent of seagrass meadows within estuaries

(Carruthers et al. 2002).

Depending on local conditions, SLR (and other climate change factors) could lead to decreased

seagrass productivity, local to large scale loss due to decreased light, and changes in species

composition and distribution (Connolly, 2012). It is expected that an increase in water depth will

result in a horizontal shift in the position of seagrass meadows, should suitable habitat be present

in newly inundated areas. SLR and other climate change processes (particularly altered rainfall

patterns) could also influence other key controls on seagrass meadow extent and community

structure. Poor water quality may also directly influence aquatic organisms within the seagrass

zone. These organisms are a key component of the estuarine food chain and any impacts on them

could influence terrestrial fauna reliant on them as a food source, such as migratory waders.

6.5.1.2 Mangroves

As mangroves grow in calm intertidal habitats with a low profile, SLR has the potential to impact on

large areas of this habitat within the study area. Mangroves have demonstrated adaptability and

resilience and are highly successful colonisers given appropriate sedimentation and hydrological

conditions. Under SLR, it is anticipated that ocean-facing mangroves will regress as a result of

inundation and upper mangrove communities will transition into locations previously occupied by

coastal saltmarsh and floodplain freshwater wetlands. Mangroves may also migrate upstream in

response to changes to tidal planes.

The extent of mangrove colonisation will be dependent on the landform and profile of the intertidal

zone. Steep bank profiles and narrow longitudinal areas of intertidal habitat in the upper reaches

are likely to restrict extensive mangrove establishment. Constructed barrages across the floodplain

may restrict expansion of mangroves with the tidal front. Coastal development in the study area

may also hinder the landward migration of mangroves and result in a loss of mangroves due to

coastal squeeze.

Quantifying the impact of SLR on mangroves is complex and depends in part on hydrology and

rates of sedimentation. Availability of suspended sediments, sediment type and water storage

capacity, rates of below-ground root growth and decomposition and sediment compaction will all

influence the rate of sedimentation in mangroves and in turn their ability to colonise (DCC, 2009). It

is generally considered that if the rate of SLR exceeds sedimentation rates there may be an overall

loss of mangrove extent (DCC, 2009). Conversely, if the rate of sedimentation in mangrove

communities exceeds SLR, then there may be an opportunity for landward retreat of mangroves

and their extent may increase or remain unchanged (DCC, 2009).



Figure 6-5 Predicted High Value Natural Asset SLR Impacts



Changes to mangrove health may reduce their resilience to SLR. Potential processes that could be

affected by SLR that may lead to indirect impacts to mangrove health include:

• Changes to soil salinity - which is a function of tidal inundation, rainfall, groundwater seepage

and evaporation (DCC, 2009); and

• Increased pollutant loads – due to tidal inundation of agricultural lands with potentially high

nutrient, sediment and agricultural chemical load of the floodplains. Export of sulfuric acid and

metals associated with the presence of ASS may also occur.

Whilst an influx of nutrients may assist in the incursion of mangroves into saltmarsh and wetland

areas, and mangroves are generally tolerant of poor water quality, with prolonged exposure to high

levels of pollution and in the presence of agricultural chemicals (particularly diuron), mangrove

metabolism and productivity may be compromised (MacFarlane, 2001). Poor water quality may

also directly influence aquatic organisms within the mangrove zone. These organisms are a key

component of the estuarine food chain and any impacts on them could influence terrestrial fauna

reliant on them as a food source, such as migratory waders.

6.5.1.3 Coastal Saltmarsh

Coastal saltmarsh frequently occurs on the landward side of mangroves in low energy habitats

within the high tide zone. Their distribution and composition are determined by the combination of

elevation, salinity and frequency of inundation. They are often subject to daily inundation by saline

waters at high tide with upper marsh zones only being reached by the highest tides. Coastal

saltmarsh plants are adapted to hypersaline conditions which most other vegetation cannot

tolerate. As saltmarsh grow in and adjacent to intertidal habitats with a low profile, a rise in sea

level has the potential to impact on large areas of this habitat within the lower and mid reaches of

the study area.

Similar to the response of mangroves, provided sedimentation is able to maintain surface elevation

at the same or greater rate than SLR, coastal saltmarsh would naturally migrate landwards in

response to a shift in the tidal front. However, coastal saltmarsh is particularly prone to coastal

squeeze i.e. these communities tend to occur between landward coastal development and the

impacts of SLR on mangroves on the littoral front, which may prevent landward migration of

saltmarsh as sea levels rise. Other urban and agricultural impacts, particularly the loss of

connectivity, altered sediment dynamics and increased nutrient runoff, will also reduce saltmarshes

resilience to SLR.

As discussed above, under SLR there may be a decline in water quality as a result of tidal

inundation of agricultural lands with potentially high nutrient, sediment, ASS and agricultural

chemical loads. An influx of nutrients may assist in the incursion of mangroves into saltmarsh. In

addition, prolonged exposure to high levels of pollution may compromise saltmarsh productivity and

saltmarsh vulnerability to SLR. This may also impact on benthic organisms within the saltmarsh

zone affecting terrestrial fauna reliant on them as a food source, such as migratory waders.



6.5.1.4 Swamp Oak Forest

Swamp oak forest communities occur above the tidal limit, frequently on the landward side of

coastal saltmarsh, where the groundwater is saline or sub-saline, on waterlogged or periodically

inundated flats, drainage lines and estuarine fringes. Casuarina glauca can withstand short periods

of inundation and is tolerant of very saline conditions (Clarke and Allaway, 1996). Temporary

inundation is unlikely to cause any significant change in these communities, however, any

permanent inundation is likely to cause a retreat of the tree line from the water edge.

There is potential for the intrusion and retreat of tidal waters in areas of known acid sulfate soils to

cause acid scalds and iron staining, resulting in minor loss of swamp oak forest. This phenomenon

was experienced near Cairns where changes in site hydrology and chemistry (caused by

reintroduction of tidal inundation) lead to the reformation of pyrite and iron minerals on the soil

surface (Johnston et al. 2009). The location and size of areas that may be subject to these impacts

is not yet known, but is expected to be a small proportion of those areas (probably small

topographic hollows) affected by SLR.

6.5.1.5 Floodplain Habitats

Freshwater Wetlands and Swamp Sclerophyll Forests

These habitats are associated with periodic or semi-permanent inundation by freshwater, although

there may be minor saline influence in some. Wetland plant species have physiological limits on

the level and duration of inundation and salinity levels, and flow rates and erosion can effect

recruitment. Therefore any change in the depth, quality and duration of inundation levels within

these habitats will have an impact on their distribution and composition. Freshwater wetlands can

tolerate minor and temporary saline intrusion, however, regular inundation is likely to result in a

shift in dominance to swamp oak, mangroves and potentially saltmarsh species.

Broad-leaved paperbark (a dominant species in some of these communities) is known to tolerate

low salinity up to 8,000 µS/m (Greening Australia, 2014) with seawater being approximately

50,000-58,000 µS/m. Regular to permanent inundation with salt water would lead to reduced

growth and germination of this species, and other wetland species associated with freshwater

conditions. In this case, Casuarina glauca (which occurs in close association with Melaleuca

communities), mangroves and saltmarsh species may be favoured and become the dominant

species.

As tidal influences in low-lying terrestrial lands increase as a result of SLR there is likely to be a

landward migration of wetland communities. The rate of wetland transition will depend on

geomorphological features (such as slope, substrate and erosion and sedimentation rates),

groundwater influences, saline intrusion, inundation levels, climatic features (particularly rainfall),

land use and plant community composition. Coastal development in the study area may hinder

wetland migration and result in a loss of total extent due to coastal squeeze or lack of suitable

habitat.

Sediment trapping, carbon sequestration and nutrient cycling will all decline with a reduction in

wetland extent (DCC, 2009). This may result in higher turbidity and nutrient loading in nearshore

waters (DCC, 2009). With potential reductions in floodplain wetland habitat, loss of wetland flora

Bellingen Shire Estuary Inundation Mapping 106 Interpretation and Risk Based Assessment of the Ecological Impacts


and fauna diversity is also likely to occur as mangroves, swamp oak and potentially saltmarsh

encroach into them. This may impact on threatened species reliant on these habitats. For example

some areas of potential wetland habitat for wallum froglet may be affected by potential saline

incursion as a result of SLR. Wallum froglet has been noted breeding in ponds with salinity of 35 –

100 ppm (Simpkins et al. 2014). This species is not salt tolerant and would not remain in an area

subject to saline intrusion.

As discussed above, there is potential for the intrusion and retreat of tidal waters in areas of known

acid sulfate soils to cause acid scalds and iron staining, resulting in minor loss of habitat in

freshwater wetlands. The location and size of areas that may be subject to these impacts is not yet

known, but is expected to be a small proportion of those areas (probably small topographic

hollows) affected by SLR.

Rainforests and Subtropical Coastal Floodplain Forest

These groundwater-dependent communities generally occupy alluvial flats with rich, moist silts. As

tidal influences in low-lying terrestrial lands increase as a result of SLR, there may be direct

impacts on these communities resulting in losses in community extent and/or condition. The rate

and extent of loss and/or condition will depend on a range of factors particularly freshwater inflows

and changes to groundwater quality and depth. Any habitat transition in these communities will be

very slow due to inherently low levels of recruitment and will be dependent on availability of habitat

conditions free from fire and other threatening processes, such as weed invasion and adjacent

landuses.

6.5.1.6 Riparian Corridor

SLR may result in localised changes in sites of erosion and accretion along the main channel and

tributaries, which would impact on the riparian corridor. The riparian corridor supports narrow

fringes of Swamp Oak Forest along the lower reaches of the Bellinger River which will be

susceptible to SLR due to coastal squeeze brought on by roads and access tracks. Narrow fringes

of Lowland Rainforest on the Floodplain along the mid reaches of the Kalang River will also be

susceptible to SLR.

6.5.1.7 Groundwater Dependant Ecosystems

Saline intrusion and/or inundation caused by SLR would probably be the most significant impact on

coastal groundwater resources due to climate change, particularly for shallow sandy aquifers along

low-lying coasts (Timms et. al., 2008). SLR can potentially impact groundwater through saline

intrusion and inland migration of the fresh-saline interface and saline inundation and flooding of

unconfined aquifers by seawater (Timms et. al., 2008). Fresh water contaminated by seawater may

render it unsuitable for sustaining GDE’s (Timms et. al., 2008). Increased mean sea-levels could

also change groundwater discharge dynamics.

6.5.1.8 Beaches

Sandy beaches are dynamic environments which undergo continual processes of erosion and

accretion and overall there is a global trend of recession of most sandy beaches. With SLR

beaches are likely to erode and migrate inland. Provided the beaches of the study area can evolve



naturally there should be a continuum of foreshore sandy habitats in the study area following SLR.

This will be especially significant for species reliant on beach habitats such as nesting marine

turtles and migratory waders. However, where the beach lies in a coastal squeeze between

development and predicted high tides, sandy foreshore habitats will be vulnerable to fragmentation

and loss due to the impacts of SLR. Vulnerable fauna most at risk to these impacts will be turtles

and waders using the supra-littoral habitats. These habitats are likely to be replaced with sea walls

and the surf zone where coastal squeeze is an issue. Management actions such as beach

nourishment will only temporarily ameliorate these impacts.

6.5.1.9 Threatened Species

Appendix D contains a list of threatened species known or potentially occurring in the study area

and surrounds, and their associated habitat types and vulnerability to SLR.

Potential impacts of SLR on flora and fauna species in the study area are generally related to

impacts on habitat quality and extent. Many species known from the study area would not be

considered to specialise in one particular habitat and are relatively adaptable to minor losses or

changes in the areas of available habitat. For example, a shift in community composition between

broad-leaved paperbark and swamp oak may result in fewer nectar reserves available as a food

source for birds and arboreal mammals. Fauna groups using these habitats may be found at a

lesser density should this shift occur. Shifts in the diversity and composition of the groundcover

may also occur (i.e. increase in more salt-tolerant species such as Sporobolus virginicus) which

may have some minor effects on fauna feeding patterns.

Some species are habitat specialists and will be more vulnerable to the impacts of SLR on areas of

essential habitat. The effects of potential losses of freshwater wetlands on acid frogs, beach

erosion effects on turtles and waders, and changes in aquatic biota in mangroves and the potential

flow on effects to waders are described above. In addition, the effects of poor water quality

resulting from SLR into agricultural lands on habitat specialists such as migratory waders and acid

frogs have been discussed.

6.6 Assessment of Risk Similar to the assessment of risk to infrastructure and property (see Section 4), an assessment of

risk has been undertaken for the high value natural assets. Table 6-2 summarises the risk of

inundation and salinity intrusion to EEC’s within subcatchments of the study area under the

immediate, 2050 and 2100 SLR scenarios. Based on the risk assessment the following High Value

Natural Assets are most at risk to SLR within the study area:

• Coastal Saltmarsh (low to high risk);

• Swamp Oak Floodplain Forest (medium risk);

• Freshwater Wetlands on Coastal Floodplains (medium to extreme risk);

• Swamp Sclerophyll Forest on Coastal Floodplains (medium to extreme risk);

• Lowland Rainforest (high risk);

• Lowland Rainforest on Floodplain (medium to extreme risk);



• Littoral Rainforest (extreme risk); and

• Subtropical Coastal Floodplain Forest (medium to extreme risk).

Recommended mitigation options to address these SLR threats are discussed below.



Table 6-2 Sea Level Rise Risk Assessment and Mitiga tion Options for High Value Natural Assets

Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?

No Regrets Actions

Option 1 (recommended) Option 2

URUNGA

URUNGA Coastal Saltmarsh EEC

Ecological Community High High High Yes

-maintain extent and condition

- restoration and connectivity to potential new habitats

- connectivity to potential new habitats

URUNGA Freshwater Wetland EEC

Ecological Community Extreme Extreme Extreme Yes

- maintain extent

- weed management

- water quality protection



URUNGA Littoral Rainforest EEC


Extreme Extreme Extreme Yes

- maintain extent

- weed management

- fire management


- seed banking and propagation


URUNGA Mangrove Ecological Community Medium Medium Medium

URUNGA

Sub-tropical Coastal Floodplain Forest EEC


- maintain extent

- weed management

- fire management



URUNGA Swamp Oak Floodplain Forest EEC

Ecological Community Medium Medium Medium

URUNGA Swamp Sclerophyll Forest EEC


- maintain extent

- weed management







No Regrets Actions


RALEIGH

RALEIGH Coastal Saltmarsh EEC


High High High Yes -maintain extent and condition


- land acquisition to provide buffers and potential new habitat


RALEIGH Freshwater Wetland EEC


- maintain extent

- weed management


- grazing management

- ASS management




RALEIGH Littoral Rainforest EEC


- maintain extent

- weed management

- fire management




RALEIGH

Lowland Rainforest on Floodplain EEC


- maintain extent

- weed management

- fire management




RALEIGH Mangrove Ecological Community Medium Medium Medium

RALEIGH



- maintain extent

- weed management

- fire management


- land acquisition to provide buffers and potential new





No Regrets Actions


habitat

RALEIGH Swamp Sclerophyll Forest EEC


- maintain extent

- weed management



- ASS management




MYLESTOM

MYLESTOM Coastal Saltmarsh EEC


Low Medium Medium

MYLESTOM Littoral Rainforest EEC


- maintain extent

- weed management

- fire management




MYLESTOM Mangrove Ecological Community Medium Medium Medium

MYLESTOM



- maintain extent

- weed management

- fire management







No Regrets Actions


MYLESTOM Swamp Sclerophyll Forest EEC


Not Applicable Medium High Yes

- maintain extent

- weed management



- ASS management




REPTON

REPTON Coastal Saltmarsh EEC


-maintain extent and condition




REPTON Freshwater Wetland EEC



- maintain extent

- weed management



- ASS management




REPTON



- maintain extent

- weed management

- fire management




Bellingen Shire Estuary Inundation Mapping 113 Interpretation and Risk Based Assessme nt of the Ecological Impacts



No Regrets Actions


REPTON Swamp Sclerophyll Forest EEC



- maintain extent

- weed management



- ASS management




BRIERFIELD

BRIERFIELD Freshwater Wetland EEC


- maintain extent

- weed management



- ASS management




BRIERFIELD Lowland Rainforest EEC


Not Applicable High High Yes

- maintain extent

- weed management

- fire management




BRIERFIELD



- maintain extent

- weed management

- fire management




BRIERFIELD Swamp Sclerophyll Forest EEC


- maintain extent

- weed management



- land acquisition to provide buffers and





No Regrets Actions



- ASS management

potential new habitat

FERNMOUNT

FERNMOUNT Freshwater Wetland EEC


- maintain extent

- weed management



- ASS management




FERNMOUNT


Ecological Community Medium High High Yes

- maintain extent

- weed management

- fire management




FERNMOUNT Swamp Sclerophyll Forest EEC


- maintain extent

- weed management



- ASS management




VALERY

VALERY Freshwater Wetland EEC


- maintain extent

- weed management

- water quality


- land acquisition to provide buffers and





No Regrets Actions


protection


- ASS management

potential new habitat

BELLINGEN

BELLINGEN Freshwater Wetland EEC


- maintain extent

- weed management



- ASS management




BELLINGEN Lowland Rainforest EEC


Not Applicable

Not Applicable High Yes

- maintain extent

- weed management

- fire management




BELLINGEN



Not Applicable

Not Applicable Medium

Bellingen Shire Estuary Inundation Mapping 116 Summary and Discussion


7 Summary and Discussion

7.1 SLR and Changed Frequency of Inundation A key impact of SLR on tidal inundation is that the occurrence of significant inundation events will

become more frequent. An example of this is that under 0.9 m of SLR, a king tide event will

produce a peak tidal inundation level that currently only occurs during the 100-year ARI event. This

means that instead of a peak offshore tidal level of 2.6 m AHD occurring on average once every

100 years, under 0.9 m of SLR, it is likely to occur several times a year during king tide conditions

(see Table 7-1). Under just 0.4 m of SLR, a king tide event which currently only occurs on average

only a few times each year (with a peak level of 2.0 m AHD), will create a marginally lower level of

inundation than is currently experienced (on average) once every 20 years.

Table 7-1 Adopted Ocean Levels for Bellinger-Kalang Estuary and Coastline

Design Event 0 m SLR (Current)

+0.4 m SLR

+0.7 m SLR

+0.9 m SLR

+1.4 m SLR

Spring Tide 0.69 (0.70) 1.09 (1.10) 1.39 (1.40) 1.59 (1.60) 2.09 (2.10)

King Tide 1.08 (1.60) 1.48 (2.00) 1.78 (2.30) 1.98 (2.50) 2.48 (3.00)

20-year ARI tide 1.60 (2.20) 2.00 (2.60) 2.30 (2.90) 2.50 (3.10) 3.00 (3.60)

100-year ARI tide 2.10 (2.60) 2.50 (3.00) 2.80 (3.30) 3.00 (3.50) 3.50 (4.00)

Note: values shown in italics adopted for the coastline (Dalhousie Creek and Oyster Creek)

7.2 Tidal Inundation The purpose of the study is to produce a ‘first-pass’ assessment of areas that may be at risk from

tidal inundation due to SLR, which may be used by Council to undertake further studies in order to

evaluate potential risks associated with the design inundation events. In particular, an attempt has

been made to highlight key areas that are susceptible to tidal inundation which will be exacerbated

by rising sea levels.

The areas subject to tidal inundation are based on interpretation of the mapped inundation extents

provided in Appendix B which are provided for the purpose of broad-scale assessment. It should be

noted that changes to inundation are shown as overlays to recent (2009) aerial photography which

should be considered in view of the local topography and the broader inundation extent mapped for

the area.

Inundation extents include the main waterway areas of the Bellinger and Kalang River which are

crossed by several bridges. Further analysis of the peak water level estimated at major bridges

crossing the Bellinger and Kalang Rivers is summarised in Table 7-2. The results show that major

bridge crossings would not be subject to tidal inundation for all design events up to and including a

major storm event (100-year ARI tide) with 1.4 metres of SLR.

Further discussion of changes to tidal inundation extents due to sea level rise for the Bellinger-

Kalang estuary, Dalhousie Creek and Oyster Creek is presented in the following sections.



Table 7-2 Peak Tide Level at Major Bridge Crossings

Bridge Crossing Deck

Level* (m AHD)

100-year ARI Peak Water level (m AHD) SLR 0.0m

SLR 0.4m

SLR 0.7m

SLR 0.9m

SLR 1.4m

Bowraville Road at Brierfield 10.0 2.1 2.4 2.6 2.8 3.3

Newry Island Drive at Urunga 6.1 2.0 2.3 2.5 2.7 3.2

Pacific Highway at Urunga 9.5 2.0 2.3 2.6 2.8 3.2

Railway at Urunga 8.7 2.0 2.3 2.6 2.8 3.2

Railway at Repton 9.7 2.0 2.4 2.6 2.8 3.2

Old Pacific Highway at Raleigh 6.8 2.0 2.4 2.6 2.8 3.2

Pacific Highway at Raleigh 8.5 2.1 2.4 2.6 2.8 3.2

Bridge Street at Bellingen 4.0 2.3 2.6 2.8 2.9 3.3 * Based on LiDAR and bridge structure data adopted by the WMA 2012 flood model

7.2.1 Bellinger River

The SLR maps of spring tide inundation show that low-lying mangrove and saltmarsh habitat (in

particular around Urunga Lagoon and Urunga Island) will receive regular (weekly) tidal inundation

with 0.4 m of SLR. There are also several other small floodplain areas near Mylestom and

Fernmount where the modelling predicts increased regular tidal inundation with 0.4 m of SLR.

The area of regular (spring tide) inundation increases significantly with a SLR allowance of 0.9 m

and 1.4 m mainly impacting farmland and unsettled areas. However, the 0.9 m and 1.4 m SLR

scenario is estimated to cause regular nuisance inundation of a number of rural properties in the

townships of Mylestom (near Mylestom Drive and Yellow Rock Road), Repton (near Perrys Road

and on the north western side of the Pacific Highway) and Raleigh. Inundation upstream of these

localities is much less significant than the inundation expected downstream.

The existing (0 m SLR) 20-year tidal event (1.6 m AHD) may inundate areas of low-lying floodplain

property around Back Creek and Boggy Creek, and northwest of Repton. Inundation further

upstream the Bellinger River is limited to a few wetland areas between Raleigh and Fernmount. A

SLR of 1.4 m for the 20-year tidal event would drastically increase the inundation experienced in

these areas as well as new areas including: the broad floodplain area between Mylestom and

Raleigh, and to the northwest of Repton and Raleigh; areas to the west of Yellow Rock Road and

to the east of the Pacific Highway; and cleared land between Repton and Mylestom.

The existing (0 m SLR) 100 year tidal event (2.1 m AHD) is predicted to inundate to a level similar

to the 20-year tidal event with a SLR of 0.4 m. Again sections of rural property within the floodplain

may be inundated. SLR may exacerbate this less frequent inundation resulting in events that

inundate the vast majority of the Bellinger River floodplain around the townships of Raleigh,

Mylestom, Repton, Fernmount and Bellingen. With SLR of 1.4 m, high or extreme risk is calculated

for the following:

• At Raleigh, several rural, residential and primary production properties; the Raleigh Waste

Management Centre, and sewer / stormwater services. Other assets including numerous minor



roads, part of the North Coast Railway and Pacific Highway and heritage building items (i.e. a

farmhouse). Natural assets include EEC’s of coastal saltmarsh, freshwater wetland, littoral

rainforest, lowland rainforest, subtropical coastal floodplain forest and swamp sclerophyll forest;

• At Mylestom, minor local roads including George Street, Mylestom Drive, River Street and an

unnamed road. Natural assets include EEC’s littoral rainforest, subtropical coastal floodplain

forest and swamp sclerophyll forest;

• At Repton, residential property off Mylestom Drive and rural property at Baily Street, Mylestom

Drive and Perrys Road; minor roads including Keevers Drive, Mylestom Drive and River Street;

and a heritage listed Ruined Timber Mill. Natural assets include EEC’s of coastal saltmarsh,

freshwater wetland, subtropical coastal floodplain forest and swamp sclerophyll forest;

• At Fernmount, rural property off Waterfall Way; primary production land off Nicolson Street and

Waterfall Way; a major road (i.e. Waterfall Way) and minor roads including Baker Street,

Nicholson Street and an unnamed road. Natural assets include EEC’s of freshwater wetland,

subtropical coastal floodplain forest and swamp sclerophyll forest; and

• At Bellingen, rural properties off North Bank Road, Slarkes Road and Wheatley Street; primary

production land off Cahill Street, North Bank Road, Waterfall Way and Wheatley Street; minor

local roads including Bridge Street, Doepel Street, John Glyde Road, North Bank Road and

Slarkes Road; and low-lying sewer and stormwater services (i.e. rising main and drainage main)

near those localities. Natural assets include EEC’s of freshwater wetland, and lowland

rainforest.

7.2.2 Kalang River

The SLR maps of spring tide inundation show only marginal increase to inundation experienced

along the Kalang River with 0.4 m of SLR. The most notable change would be the connection

between Boggy Creek and Back Creek which only occurs at present under king tide conditions.

The area of regular (spring tide) inundation increases significantly with a SLR allowance of 0.9 m

and 1.4 m regularly inundating large parts of the Urunga Golf course and adjacent riverfront

properties as well as rural properties located on Newry Island. With projected SLR increases of this

magnitude, regular tidal inundation may be experienced by creeks (e.g. Picket Hill Creek) and low-

lying wetlands fringing the Kalang River between Tarkeeth and Newry Island. Regular inundation

extents upstream of Tarkeeth are much less significant than downstream localities and isolated to

those small tributaries joining the river.

More infrequent events (i.e. king tides) with 1.4 m of SLR may also affect similar low-lying areas,

albeit with marginally greater tidal excursion than that predicted for the spring tide scenario. A few

low-lying industrial precinct properties off Marina Crescent, riverside residential properties on

Newry Island and off Crescent Close, and low-lying residential properties along Mogo Street

overlooking Urunga Lagoon may also be affected. Tidal excursion may also increase to the wetland

to the south of Hillside Drive, affecting the rear of some properties located at its westernmost

extent.

The existing (0 m SLR) 20-year tidal event may inundate part of the Urunga Golf Course and

nearby private properties to a similar level as a spring tide event with a SLR of 0.9 m. For this



scenario, inundation further upstream the Kalang River is limited to fringing wetlands between

Tarkeeth and Newry Island. A SLR of 1.4 m would exacerbate the inundation experienced in these

areas as well as the low-lying properties noted above.

As noted above, the existing (0 m SLR) 100 year tidal event is predicted to inundate to a level

similar to the 20-year tidal event with a SLR of 0.4 m. Under this rare scenario, rural property within

the floodplain may be inundated as well as low-lying properties adjacent to the Kalang River and

Urunga Lagoon. SLR of 0.9 m and 1.4 m may exacerbate inundation further resulting in events

affecting a majority of the narrow floodplain between Tarkeeth and Urunga. With a SLR of 1.4 m,

numerous properties situated on Newry Island and at Urunga in the vicinity of the golf course /

tennis courts and lagoon would be affected. For this scenario, high and extreme risk is calculated

for the following:

• At Urunga, numerous residential properties, some rural and primary production properties at the

following locations (i.e. Burrawong Parade, Crescent Close, Hollis Close, Island Place, Marina

Crescent, Marshall Place, Melaleuca Place, Morgo Street, Newry Island Drive, Old Punt Road,

Pacific Highway, Riverside Drive, Short Cut Road, South Arm Road, The Grove, Vernon

Crescent and Yellow Rock Road); and associated sewer services (i.e. gravity main, pressure

main, pumping main, rising main, transfer main) and stormwater services (i.e. drainage mains)

in the area. Community assets include the Urunga Head Holiday Park and cultural planting and

Urunga Scouts – Bellinger Head State Park. Natural assets include EEC’s of coastal saltmarsh,

freshwater wetland, littoral rainforest, subtropical coastal floodplain forest and swamp

sclerophyll forest; and

• At Brierfield, several rural properties / primary production land and minor roads including

Bowraville Road, Martells Road, South Arm Road and Hains Lane. Natural assets include

EEC’s of freshwater wetland, lowland rainforest and swamp sclerophyll forest.

7.2.3 Dalhousie Creek and Oyster Creek

At present, both Dalhousie Creek and Oyster Creek currently experience only minor tidal

inundation during spring and king tides. Increased inundation extents predicted due to SLR is

highly localised and controlled by the steep topography surrounding the ICOLLs. No private

properties are expected to be affected by the predicted increased inundation during infrequent tidal

inundation events (i.e. 20-year and 100-year ARI) even with 1.4 metre of SLR.

7.3 Limitations of Inundation Mapping and Modelling There are a number of limitations to the current study which influence how the results should be

interpreted. These limitations are summarised in the points below:

• The inundation extents estimated for Dalhousie Creek and Oyster Creek are derived from the

simple ‘bath tub’ approach which assumes that a constant water level across the entire

waterway provides a suitable calculation of oceanic inundation for small coastal waterbodies

such as those present in the study area;

• Models have not been calibrated to storm surge events (only flood or typical tidal conditions).

While the existing calibrations provide reasonable confidence in the model predictions,



additional calibration to actual significant tidal inundation events would further increase

confidence in model predictions;

• Likewise, the estuary model is not calibrated for hydrodynamics (water level and flow) or

advection/dispersion (salinity) and as such the focus should be on the relative changes to

inundation depth and salinity between the different SLR scenarios rather than the absolute

values predicted by the model;

• The study does not consider river flooding and tidal storm surges occurring at the same time,

and the construction of future defences which may be built to reduce the impact of SLR;

• There is some uncertainty surrounding the design wave setup conditions at trained river

entrances. A conservative approach has been adopted for the study in light of DECCW (2010)

guidelines and published work relating to wave setup for various entrance conditions;

• Coastal inundation lines do not consider wave run-up, overtopping or coastal erosion; and

• While the inundation model does not include underground sewer or stormwater pipes which

may convey tidal waters behind flood defences, the use of extrapolated water levels in the

mapping process extends inundation into low lying lands beyond flood defences. Higher

resolution 1D-2D modelling incorporating all underground pipe networks could be used to better

assess the risk due to this form of flood risk.

The results of this study should be interpreted as a ‘first pass’ assessment that may be used to

gauge the magnitude of the SLR issue in the estuary. Further refinement will be required to

develop a more detailed understanding of SLR inundation, which may also consider further

modelling assessment(s) to quantify the mitigative performance of potential management options.

7.4 Suggested Provisions for Reviewing and Updating SLR Benchmarks The NSW Floodplain Development Manual suggests that floodplain management plans are

reviewed approximately every five (5) years. While this SLR mapping study does not sit directly

under provisions outlined in the manual, it is recommended that revised estimates of tidal

inundation under SLR scenarios be re-assessed every five to ten years or when significant new

information or guidelines become available.

New information or guidelines which would influence when an update or review of the SLR

inundation maps should occur include:

• Changes to NSW Government Flood Policy;

• Updates to IPCC estimates of SLR (the IPCC Fourth Assessment Report (AR4) was completed

in early 2007. The IPCC is currently starting to outline its Fifth Assessment Report (AR5) which

will be finalized in 2014);

• Actual local observations of SLR;

• New LiDAR data becomes available; or

• Significant changes to the hydraulics of the estuaries.



7.4.1 Independence of Mapping from Changes to Projected Rates of SLR

Updates to benchmarks will not influence the mapped outputs produced in the study which provide

an indication of tidal inundation for 0.0, 0.4, 0.9 and 1.4 metres of SLR. The majority of uncertainty

regarding SLR estimates is to do with the projected rate of sea level rise. So while the current

benchmarks assume that 0.4 m of SLR will occur by 2050, the maps indicate what 0.4 m of SLR

looks like and not when this will occur. If the rate of sea level rise is slower than currently

calculated, then 0.4 m of SLR may not occur to say 2100. However, if the rate of SLR is quicker

than currently calculated, it may occur closer to 2040 for example.



7.5 Sea Level Rise Mitigation Options

7.5.1 Estuary Inundation

Key management options that are recommended to Council for managing estuary inundation hazard broadly are outlined in Table 7-3. The options have

been collated based on the multi criteria analysis conducted in the CZMS, then refined to suit the needs of the assets types in the context of Bellingen

Shire. Detailed descriptions of all options are provided in Appendix E of the Bellingen CZMS (2014).

Table 7-3 Recommended Options for Managing Estuary Inundation Hazard

Option: Monitoring

Detail Asset Managed

Monitoring: to collect better information regarding coastal processes and to determine when a risk is approaching. A trigger may be in relation to flood level or flood frequency. The trigger must allow sufficient time for the preferred management option to be funded, approved an implemented. Key monitoring activities would include: • Monitoring of water level / frequency and depth of inundation events for key assets (refer to risk register in

Appendix C) for high/extreme risk assets.

• Monitor distribution and health of estuary ecology, by undertaking regular mapping of coastal habitats (ever 2-5 years), with more regular targeted monitoring activities occurring (e.g. mangrove landward expansion) occurring (e.g. yearly) when a local change in distribution / health of a high value community is identified.

No Regrets Option

All assets with a focus on those at high / extreme risks

Option: Asset Management Planning


Asset Management Planning: incorporate the likelihood of the coastal hazards to impact upon Council’s assets (e.g. buildings, roads, services etc). The likelihood of a hazard impact and expected timeframe should be incorporated / considered by Council’s asset managers when calculating the time for and cost of replacing an asset. The asset management plan should also incorporate the appropriate action to manage the hazard (refer Audit of Existing Council Assets option below), such as relocating an asset, redesigning an asset, or otherwise using different materials/construction to ensure the replacement asset withstands the hazard over its expected life, avoiding future costs to Council. That is, the approach aims to avoid replacing “like for like” when an asset is in a hazardous location. For non-council assets (e.g. railway, RTA roads), the hazards information should be provided to the asset owner, to inform of the likely risk and enable the asset owner to develop an appropriate hazard management response. Council should encourage continued contact with such asset owners to ensure that their management responses do not negatively impact or contradict the approach and actions of Council to managing coastal hazards.

No Regrets Option

Council’s assets, non-council assets (railway, RTA roads etc)



Option: Audit of Existing Council Built Assets


Audit of Existing Council Assets: to support the management of coastal hazards when assets are replaced. The audit should initially focus upon those assets at extreme or high risk over the immediate timeframe, and then extend to high / extreme risks at future timeframes and so on. The audit should determine, for each asset at risk, which of the following actions is most suitable: • Relocation, to move the replacement asset beyond the area of likely hazard over its lifespan; • Redesign of the replacement asset, to withstand hazard impacts (e.g. floor levels for buildings, salt resistant

materials and / or tidal flaps for stormwater outlets, as so on); or • Manage to fail, where it is suitable to remove instead of replace an asset at the end of its life. • As an interim option, life extension activities (including repairs following damage) may also be considered, until

such time as the preferred action (relocate or redesign) can be afforded. There may need to be further investigation of redesign options for existing assets, for example, investigating salt resistant piping for stormwater, or tidal flaps to reduce inundation, and so on. This option effectively selects the appropriate option from relocation, redesign/retrofit or otherwise for individual assets, accounting for coastal hazards in combination with the other priorities for Council. Refer to Appendix E in the CZMS (BMT WBM, 2014) for further details on ‘relocation’, ‘retrofit/redesign’ and ‘manage to fail’ options.

No Regrets Option

All assets with a focus on those at high / extreme risks for immediate, then future timeframes. Assets at lower risk can then be assessed if resources permit

Option: Use of Existing Flood Policy


Use of the existing Flood Policy: is likely to be suitable as an interim measure to regulate estuary inundation risks due to periodic ocean events for future development and redevelopment of existing properties. Interim use of the policy should only be done until the next amendment of Councils Floodplain Risk Management Plan (to incorporate the outcomes of the most recent flood modelling study undertaken in 2012 for the Lower Floodplain). Revision of the Floodplain Risk Management Plan should then be considered as the peak strategy for regulation of all possible inundation in the study area. The linkages between fluvial inundation, coastal inundation and estuary inundation can be clearly documented in that Plan and the most appropriate policy response specified.

No Regrets Option

Redevelopment of existing assets or new developments

Option: Community Education


Community Education: is aimed at ongoing updates to community regarding occurrence of climate change, particularly sea level rise, and must include an outline of the actions being undertaken by Council and others to manage and mitigate risks. The aim of education is to build resilience of the community to managing coastal hazards, when they manifest.

No Regrets Option



Option: LEP Review and Rezoning


LEP Review and Rezoning: to ensure that land is not developed inappropriately. That is, land that is known to be at risks from coastal hazards, particularly where such land is currently vacant, should be rezoned (or existing zoning retained) to Environmental Management, Environmental Conservation, Public Recreation or similar. This options is appropriate for areas identified with a high or extreme risk from periodic storm driven estuary inundation (as identified in this risk assessment), as well as areas likely to be impacted by permanent estuary inundation due to sea level rise (as modelled in this study, but not addressed in this risk assessment). Rezoning / zoning of vacant land to ensure the land is not considered for development at any stage in the future. As the principal development guide for day to day assessments of developments, this option would also include updates to the DCP 2010 with specific regard to the recommendations of this study.

No Regrets Option

Areas of undeveloped land: • at high / extreme risk of storm driven –

estuary inundation

• likely to be impacted by permanent estuary inundation due to sea level rise

Option: Habitat Management


Habitat Management: should focus on high values ecological communities identified with high/extreme risks, to ensure that the health and resilience of these communities is reattained as best as possible under the increasing pressures of sea level rise. This option includes maintaining the extent and condition of the high values ecological communities at risk through the undertaking the following No Regrets actions:

• monitoring; • weed management; • water quality protection; • fire management; • grazing management; and • acid sulphate soil management. Furthermore, future management options to improve the resilience of the high value communities to sea level rise include: • restoration and connectivity to potential new habitats

• land acquisition to provide buffers and potential new habitat; and • seed banking and propagation.

Details of where to apply these specific actions/options are noted in Table 6-2, and discussed below.

No Regrets Option

Future management actions

High value ecological communities at risk of estuary inundation



7.5.2 High Value Natural Assets

High Value Natural Assets in the riparian corridor, floodplain and estuarine reaches of the Bellinger

and Kalang River estuaries are most at risk from SLR. Given their limited distribution in a largely

cleared agricultural setting, and the poor condition of the riparian vegetation, these communities

may require management intervention to improve their resilience to SLR and in the case of tidal

wetlands, assist with habitat transition. Shoo et al. (2012) modelled SLR impacts on coastal

wetlands in south-east Queensland and found that the seaward margin of wetlands are

predominantly on public land but would be lost due to SLR, whereas wetlands are potentially

gained on the landward side of SLR, but predominantly occur on private land. A similar scenario is

expected in the study area.

It is recommended that Council initially focus actions to address SLR within the extreme to high risk

locations and riparian reaches. Given the timeframes over which projected SLR impacts may occur

(2050 onwards), and the complicated interactions involved, Council will be required to develop

ongoing adaptive strategies (including action on Table 6-2 and Table 7-3) to assess and manage

SLR impacts. This will require regular monitoring to map the distribution and condition of coastal

habitats in association with SLR (see Section 7.6 for more detail).

7.5.2.1 Tidal/Near-Tidal Wetlands

Mangroves are expected to be able to colonise new habitat at a rate that keeps pace with most

SLR predictions, subject to the slope of adjacent land, the actual rate of SLR and the presence of

obstacles to landward migration of the landward boundary of the mangrove (e.g. seawalls and

other shoreline protection structures). Under SLR, it is anticipated that mangrove communities may

transition into locations previously occupied by Coastal Saltmarsh and floodplain wetlands and may

migrate further upstream with the tidal front. It is recommended that regular monitoring is carried

out to map mangrove distribution in association with SLR to identify sites of mangrove retreat and

invasion of more vulnerable communities, notably Coastal Saltmarsh. Recommended monitoring

sites within the study area are discussed in Section 7.6.

Swamp Oak Forest and Coastal Saltmarsh within the mid to lower reaches of the estuaries may be

affected by increased inundation and saline intrusion and potential changes to groundwater as a

result of SLR. SLR management actions proposed for these habitats should also focus on

conserving adjacent buffers for future natural migration in response to SLR, increasing

rehabilitation efforts through planting and weed management and improving connectivity between

habitats (i.e. restoration). These actions may assist natural transition as a result of SLR and may

help ensure that threatened wetland habitat is conserved for a range of dependant species, such

as migratory waders.

7.5.2.2 Riparian Corridor

It is recommended that actions aimed at managing SLR within all reaches focus on conserving

buffers adjacent to riparian corridors and maintaining rehabilitation efforts. This is particularly

important in the lower reaches of the Bellinger and Kalang Rivers which are most susceptible to

SLR and support Endangered Swamp Oak Forest and Coastal Saltmarsh riparian communities.



It is recommended that the width of the riparian corridor be increased through planting and

restoration and overall condition improved through weed management. The riparian rehabilitation

recommendations and priority sites outlined in the Bellinger Estuary Action Plan Reach Plan

(Bellingen Shire Council, 2011) and the Bellinger and Kalang Rivers Estuary Action Plan Stage 2

(Bellingen Shire Council, 2014) should be maintained and adapted in response to SLR. These

actions may improve the resilience of the riparian corridor to erosion whilst maintaining the

important functions of riparian vegetation, such as water quality control, and ensuring riparian

habitat is conserved for threatened species such as Koala.

7.5.2.3 Floodplain Habitats

Freshwater Wetlands and Swamp Sclerophyll Forest on the floodplains in the study area may be

affected by increased inundation, saline intrusion, mangrove invasion (particularly in Freshwater

Wetlands) and potential changes to groundwater level and quality as a result of SLR. SLR actions

proposed for these habitats should focus on conserving buffers adjacent to these wetlands for

future natural migration in response to SLR, increasing rehabilitation efforts through planting, weed

management, water quality protection, grazing management and ASS management and improving

connectivity between these communities (i.e. restoration). These actions may assist natural

transition as a result of SLR whilst maintaining the important functions of floodplain wetlands, such

as water quality control, and may help ensure that threatened wetland habitat is conserved for a

range of dependant species such as Litorea aurea (Green and Golden Bell Frog), Phaius australis

(Southern Swamp Orchid), Pteropus poliocephalus (Grey-headed Flying-fox), Litoria olongburensis

(Wallum Sedge Frog) and Crinia tinnula (Wallum Frog).

SLR actions proposed for Lowland Rainforest and Subtropical Coastal Forests on the floodplains

should focus on conserving buffers for future migration in response to SLR, increasing

rehabilitation efforts through planting and weed management and maintaining firebreaks. In

addition, given their small and isolated extent it is recommended that Lowland Rainforest species

be preserved through seed banking and propagation. These actions may assist natural transition

as a result of SLR and would help ensure these communities and associated species are

conserved.

7.5.2.4 Littoral Rainforest

SLR actions proposed for these groundwater-dependant ecosystems should focus on increasing

rehabilitation efforts to improve condition through planting and weed management and maintaining

firebreaks. In addition, given their small and isolated extent it is recommended that rainforest

species be preserved through seed banking and propagation. These actions may help ensure

these communities and associated species are conserved. Any habitat transition in these

communities will be very slow due to inherently low levels of recruitment and will be dependent on

changes in groundwater quality and depth and availability of habitat conditions free from fire and

other threatening processes, such as weed invasion and adjacent landuses.



7.6 Proposed Monitoring Sites Based on the available data and a ground truthing exercise, eight sites were identified for ongoing

monitoring of geomorphic response and ecological community change. Site selection was based

on presence of High Value Natural Assets predicted to be impacted by SLR and easy accessibility.

Table 7-4 provides a summary of the recommended monitoring sites shown in Figure 6-1.

Table 7-4 Habitat Response to SLR Monitoring Sites

Site Number

MGA Zone 56 (GDA94) Location High Value Natural Assets at

Risk to SLR Easting Northing

1 500939 6626971

Directly west of Pacific Highway and south of Marina Crescent

mangroves / mudflats

saltmarsh

SEPP14

2 501711 6627266 East of Yellow Rock Road mangroves / mudflats

saltmarsh

3 502450 6628480

South of Yellow Rock Road mangroves / mudflats

saltmarsh

SEPP14

4 500496 6625604 Adjacent to Melaleuca Place mangroves

saltmarsh

5 502400 6624232

South-eastern corner of Urunga Lagoon, approx. 400m north of Hungry Head Road

mangroves

saltmarsh

SEPP14

SEPP26

6 502690 6625470 North eastern corner of Urunga Lagoon

mangroves / mudflats

saltmarsh / salt flats

7 502700 6628820 North of site 2 floodplain wetland

8 502230 6625970 North-western corner of Urunga Lagoon

disturbed, cleared, reclaimed, mudflats

Bellingen Shire Estuary Inundation Mapping 128 Conclusions


8 Conclusions

8.1 Estuary Inundation Climate change and sea level rise have the ability to impact private and public land and assets

within the Bellingen LGA. This SLR mapping investigation was undertaken to identify areas with the

LGA that are likely to be impacted (negatively or otherwise) by SLR. The study has updated and

made use of existing (and newly developed) computer models to calculate tidal inundation in the

main river estuary and ICOLL’s located in the LGA. The study has determined the estuarine and

coastal inundation extents for a range of design ocean events and four epochs and associated

mean sea levels (MSL).

Based on the estuary inundation modelling, key areas within the Bellinger-Kalang Estuary that may

be impacted by more frequent tidal inundation (exacerbated by SLR) include:

• farmland and unsettled low-lying floodplain areas around Mylestom and Fernmount;

• a number of rural properties in the townships of Mylestom (near Mylestom Drive and Yellow

Rock Road), Repton (near Perrys Road and on the north western side of the Pacific Highway)

and Raleigh; and

• part of the Urunga Golf course and adjacent riverfront properties as well as some rural

properties located on Newry Island.

Areas that are currently not impacted by tidal inundation but may begin to experience infrequent

(i.e. 20-year and 100-year ARI events) with SLR include:

• the broad floodplain area between Mylestom and Raleigh, and to the northwest of Repton and

Raleigh;

• low-lying areas to the west of Yellow Rock Road and to the east of the Pacific Highway;

• low-lying land cleared between Repton and Mylestom;

• several rural, residential and primary production properties around the townships of Raleigh,

Mylestom, Repton and Fernmount;

• numerous rural, residential properties situated on Newry Island and waterfront properties along

the Kalang River at Urunga;

• properties at the Urunga Industrial precinct; and

• the Urunga Golf Course / tennis courts and waterfront properties in the immediate vicinity

lagoon and Urunga Lagoon.

These areas include a large area of mapped Regionally Significant Farmland (RSF). The impacts

of increased tidal inundation on soil profiles in RSF were not specifically considered in this study

however this could be investigated further in future using the mapping data derived from this study.

Due to the steep topography surrounding Dalhousie Creek and Oyster Creek ICOLLs, inundation

extents are largely confined to the main waterway and adjacent low-lying intertidal area. Private



properties and other infrastructure are not expected to experience any significant inundation during

infrequent tidal inundation events (i.e. 20-year and 100-year ARI) even with 1.4 metre of SLR.

8.2 Ecological Impacts The study area supports a range of High Value Natural Assets at risk from SLR. Based on SLR

projections, it is anticipated there may be increased inundation and saline intrusion into Coastal

Saltmarsh and Swamp Oak Forest communities in the lower and middle estuarine reaches. This

may result in landward retreat of these communities if habitat conditions are suitable and

expansion of mangroves landward and further upstream with the tidal front. Potential inundation of

floodplain wetland habitats is also anticipated for all estuary reaches.

Provided conditions are suitable for colonisation, estuarine wetland habitats are expected to

migrate landwards in response to a shift in the tidal planes. Some habitats, particularly Coastal

Saltmarsh, are prone to coastal squeeze which may prevent landward migration as sea levels rise.

This is particularly evident in the lower reaches of the Kalang River where existing Coastal

Saltmarsh communities abut residential development including roads.

Due to natural migration, low-lying, flat areas above the tidal range, particularly those that lie

adjacent to existing vulnerable habitats, may become increasingly important to protect and restore

as potential areas for future habitat migration. This includes agricultural lands which have been

previously cleared. Priority areas for protection should also be located along tributaries and creeks.

It is therefore recommended that Council considers management measures that provide buffering,

connectivity and migration of vulnerable habitats, particularly Freshwater Wetlands, Coastal

Saltmarsh, Swamp Oak Forest, Swamp Sclerophyll Forest, Lowland Rainforest and riparian

vegetation.

Various actions could be implemented by Council to protect vulnerable habitats from SLR as

follows:

• protecting land adjacent to vulnerable habitats (listed above) from development so they have

land to migrate to;

• reducing non-SLR threats such as weeds and disturbance-dependent species (such as

Phragmites) to increase habitat condition and therefore resilience; and

• remediation of lands such as low-productivity pastures through hydrological works (e.g.

introducing more natural flow regimes to assist habitat migration by either improving the function

of (or removing) artificial controls such as culverts and levees and plantings to assist habitat

establishment).

Shoo et al., 2012 identified several mechanisms which could be implemented by Council to protect

vulnerable habitats from SLR. Whilst Council may not be able to achieve many of these objectives

due to budget and planning constraints, they should be considered at the strategic level to help

reduce impacts on vulnerable habitats and to enable Council to respond if priorities and funding

change in the future:

• more stringent land-use laws, buffer controls and incentives for privately-held land protection for

habitat migration. For example, Council could educate and provide grants to encourage



landholders to preserve land for habitat migration adjacent to vulnerable habitats so susceptible

habitats have somewhere to migrate to; and other opportunities could be considered e.g. OEH

Conservation Agreements;

• preventing the construction of hard structures, such as walls and roads, adjacent to existing

vulnerable habitats which may prevent their landward migration (note: as land owners are

permitted to construct tracks on private land without consent from Council, educational

strategies may be the most effective way to address this matter);

• ongoing mapping (every 5 years in first instance then every 1 to 2 years when impacts are being

realised) to identify habitats most vulnerable to SLR and any habitat migration response that

might have occurred;

• modelling of landscape change to predict habitat change with SLR;

• assessing the adequacy of the local reserve system for maintaining vulnerable habitat

ecosystem services and functions;

• identifying priority sites for land acquisition to ensure all vulnerable habitats are protected and

which allow habitat migration; and

• increasing acquisition of vulnerable habitats and adjacent land for inclusion in the reserve

system.

Note: in relation to land-use laws and buffer controls, in many instances Bellingen Shire is fortunate

as it is likely that areas adjoining existing ecologically significant and threatened habitats are

already mapped as flood prone land and possess rural zonings that, in combination, restrict the

likelihood of development occurring that would provide an obstacle to the landward migration of at

risk communities.

Bellingen Shire Estuary Inundation Mapping 131 References


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Bellingen Shire Estuary Inundation Mapping A-1 Description of Wave Setup


Appendix A Description of Wave Setup

In addition to wind, waves can also affect the mean nearshore water levels during storms in a

process called wave setup (see Figure A-1). This occurs as a result of the transfer of momentum

from waves to the water column (see Figure A-2). Wave setup increases as the water depth

decreases and wave dissipation (or breaking) increases (FEMA, 2005).

Consider waves approaching the shoreline (see Figure A-3). Outside of the breaker zone, a

relatively small reduction in mean water level, termed a setdown, will occur. This setdown is small,

approximately 5% of the breaking wave height. However, as the waves break, they transfer

momentum to the water column, causing wave ‘setup’ than can be in the order of 10 to 20% of the

breaking wave height (FEMA, 2005). Wave setup at a river entrance (see Figure A-4) is typically

less than on the open coast due to increased water depth and reduced wave breaking (as

discussed in Section 3.1.3).

Figure A-1 Illustration of Wave Setup (FEMA, 2005)



Figure A-2 Wave Setup Due to Transfer of Momentum ( FEMA, 2007)

Figure A-3 Wave Setup and Setdown at a Beach (FEMA, 2005)



Figure A-4 Wave Setup at a River Entrance (FEMA, 20 05)

References

Federal Emergency Management Agency (FEMA) (2005). Wave Setup - Coastal Flood Hazard

Analysis and Mapping Guidelines, Focused Study Report, February 2005. Washington D.C.

Accessed 04/10/2013, URL: http://www.fema.gov/media-library-data/20130726-1541-20490-

1234/frm_p1wave1.pdf.

Federal Emergency Management Agency (FEMA) (2007). Guidelines and Specification for Flood

Hazard Mapping Partners, February 2007. Accessed 04/10/2013, URL:

http://www.fema.gov/media-library-data/20130726-1558-20490-5529/frm_cfhamagd26.pdf.

Bellingen Shire Estuary Inundation Mapping B-1 Mapping Compendium of Estuary Inundation


Appendix B Mapping Compendium of Estuary Inundation

This mapping compendium contains 40 maps each with a unique map name such as ‘event’-‘map

ID’. A list and description of each map ID is presented in Table B-1, while the location of each map

is presented in the index map on the following page.

Each map is of a given design event (100-year ARI, 20-year ARI, king tide or spring tide) and

shows changes to inundation at 0.0 (current), +0.4 m, +0.9 m and +1.4 m sea level rise increments.

Low-lying areas that are potentially vulnerable to flooding from a combination of sea level rise and

a very high tide are shown.

Table B-1 Description of Maps in each Series of the Mapping Compendium

Map ID Description

BK_1 Bellinger-Kalang Estuary – full extent

BK_2 Bellinger-Kalang – Urunga zoom

BK_3 Bellinger-Kalang – Mylestom zoom

BK_4 Bellinger-Kalang – Raleigh zoom

BR_1 Bellinger River – upstream zoom

BR_2 Bellinger River – downstream zoom

KR_1 Kalang River – upstream zoom

KR_2 Kalang River – downstream zoom

Dal Dalhousie Creek – full extent*

Oys Oyster Creek – full extent*

* inundation of Oyster Creek and Dalhousie Creek is based on a simplified ‘bath tub’ mapping procedure.

Table B-2 Description of Design Event Map Colours

Design Event Map Series Colour

Spring tide light to dark pink

King tide yellow, orange, brown

20-year ARI tide light to dark blue

100-year ARI tide light to dark purple

Bellingen Shire Estuary Inundation Mapping C-2 Asset Risk Register


Appendix C Asset Risk Register

Location Asset Name Asset Type 2010 2050 2100 Treatment Req'd

URUNGA Town Centre, Residential and Rural Property

Residential - Acacia Dr Residential Property Medium Medium Medium

Residential - Allison Pl Residential Property #N/A #N/A Low

Residential - Bellingen St Residential Property Medium Medium Medium

Residential - Burrawong Pd Residential Property High High High Yes

Residential - Christine Cl Residential Property Medium Medium Medium

Residential - Clybucca St Residential Property Low Medium Medium

Residential - Comlaroi St Residential Property Low Medium Medium

Residential - Coopers Ln Residential Property Low Medium Medium

Residential - Crescent Cl Residential Property High High High Yes

Residential - Crescent St Residential Property High High High Yes

Residential - Dolphin Crt Residential Property #N/A Medium Medium

Residential - Elizabeth Dr Residential Property #N/A #N/A Medium

Residential - Hillside Dr Residential Property Low Medium Medium

Residential - Hollis Cl Residential Property High High High Yes

Residential - Island Pl Residential Property High High High Yes

Residential - Jean Cl Residential Property #N/A Low Medium

Residential - Karen St Residential Property Medium Medium Medium

Residential - Kylie St Residential Property Medium Medium Medium

Residential - Lake Crt Residential Property #N/A #N/A Medium

Residential - Marina Cr Residential Property High High High Yes

Residential - Marshall Pl Residential Property High High High Yes

Residential - Melaleuca Pl Residential Property High High High Yes

Residential - Morgo St Residential Property High High High Yes

Residential - Mountview Cr Residential Property #N/A Low Medium

Residential - Newry Island Dr Residential Property High High High Yes

Residential - Odalberree Dr Residential Property #N/A Low Medium

Residential - Old Punt Rd Residential Property High High High Yes

Residential - Pacific Hwy Residential Property High High High Yes

Residential - Panorama Pd Residential Property #N/A #N/A Low

Residential - Raleigh St Residential Property Medium Medium Medium

Residential - River St Residential Property #N/A Medium Medium

Residential - Riverside Dr Residential Property High High High Yes

Residential - Rosedale Dr Residential Property #N/A Low Medium

Residential - Short Cut Rd Residential Property High High High Yes

Residential - South Arm Rd Residential Property Medium Medium Medium

Residential - The Grove Residential Property High High High Yes

Residential - Vernon Cr Residential Property High High High Yes

Residential - Vernon Pl Residential Property High High High Yes

Residential - Wollumbin Dr Residential Property #N/A #N/A Low

Residential - Yellow Rock Rd Residential Property Medium Medium Medium

Rural - Newry Island Drive Rural Property High High High Yes

Rural - Old Punt Rd Rural Property High High High Yes

Rural - Pacific Hwy Rural Property High High High Yes

Rural - Short Cut Rd Rural Property High High High Yes

Rural - South Arm Rd Rural Property High High High Yes

Rural - Yellow Rock Rd Rural Property High High High Yes


Forestry Land Forestry Zone Medium Medium Medium

General Industrial Land General Industrial Zone High High High Yes

Infrastructure Land Infrastructure Zoned Land Low Low Low

Primary Production - Martells Rd Primary Production High High High Yes

Primary Production - Newry Island Drive Primary Production High High High Yes

Primary Production - Old Punt Rd Primary Production High High High Yes

Primary Production - Pacific Hwy Primary Production High High High Yes

Primary Production - Short Cut Rd Primary Production High High High Yes

Primary Production - South Arm Rd Primary Production High High High Yes

Primary Production - Yellow Rock Rd Primary Production High High High Yes


Pacific Hwy Major Road Extreme Extreme Extreme Yes

Allison Place Minor Road #N/A Low Medium

Atherton Drive Minor Road High High High Yes

Bellingen St Minor Road High High High Yes

Bonville St Minor Road Low #N/A #N/A

Burrawong Pde Minor Road #N/A #N/A Low

Cemetery Rd Minor Road #N/A #N/A Low

Cemetery Road Minor Road #N/A #N/A Low

Christine Cl Minor Road #N/A #N/A Low

Clybucca St Minor Road Medium Medium Medium

Comlaroi St Minor Road Low Medium Medium

Coopers Lane Minor Road #N/A #N/A Low

Crescent Cl Minor Road High High High Yes

Dudley St Minor Road Low Medium Medium

Elizabeth Dr Minor Road #N/A #N/A Low

Gossips Rd Minor Road Low Medium Medium

Hillside Dr Minor Road #N/A Medium Medium

Hungry Head Rd Minor Road High High High Yes

Hungry Head Road Minor Road High High High Yes

Island Pl Minor Road #N/A #N/A Low

Jean Cl Minor Road #N/A #N/A Low

Karen St Minor Road Medium Medium Medium

Kylie St Minor Road #N/A #N/A Low

Marina Cr Minor Road Medium Medium Medium

Marshall Pl Minor Road #N/A #N/A Low

Martells Rd Minor Road High High High Yes

Melaleuca Pl Minor Road #N/A #N/A Low

Morgo St Minor Road High High High Yes

Newry Island Dr Minor Road High High High Yes

Old Punt Rd Minor Road High High High Yes

Orara St Minor Road #N/A #N/A Medium

Pacific Hwy Minor Road High High High Yes

Panorama Pde Minor Road #N/A Low Medium

Raleigh St Minor Road Medium Medium Medium

River St Minor Road Medium Medium Medium

Short Cut Rd Minor Road High High High Yes

South Arm Rd Minor Road High High High Yes

Titree St Minor Road Medium Medium Medium

Unnamed Road Minor Road High High High Yes

Urunga Lagoon Rd Minor Road High High High Yes

Valla St Minor Road Medium Medium Medium

Yellow Rock Rd Minor Road High High High Yes

North Coast Railway Railway Extreme Extreme Extreme Yes

Services

Gravity Main Sewer Services Extreme Extreme Extreme Yes

Pressure Main Sewer Services Extreme Extreme Extreme Yes

Private Pumping Main Sewer Services Extreme Extreme Extreme Yes

Rising Main Sewer Services Extreme Extreme Extreme Yes

Transfer Main Sewer Services High High High Yes

Urunga Wastewater Treatment Works Sewer Services #N/A #N/A Medium

Drainage Main Stormwater Services High High High Yes

Inter-allotment Drainage Main Stormwater Services High High High Yes

Water Line - Reticulation Main Water Services Medium Medium Medium

Water Line - Transfer Main Water Services Medium Medium Medium

Community Assets

North Hungry Head Beach - Beach Access (4WD) Beach Access Low Low Low

Back Creek (BCRCR) Parks, Reserves and Open Space Medium Medium Medium

Bellingen Coast Regional Crown Reserve (BCRCR) Parks, Reserves and Open Space Medium Medium Medium

Bellinger Heads State Park Parks, Reserves and Open Space Medium Medium Medium

Bellinger Keys - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Burrawong Parade - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low

Elizabeth Drive - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low

Graves x 2, Early Urunga Cemetery Parks, Reserves and Open Space #N/A #N/A Low

Maramba Park - BSC Reserve Parks, Reserves and Open Space Low Low Low

Marina Crescent - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Odalberree Drive - BSC Reserve Parks, Reserves and Open Space #N/A Low Low

Public Recreation Parks, Reserves and Open Space Medium Medium Medium

South Arm Road - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Stan Mile Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Unnamed BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Urunga Head Holiday Park & Cultural Planting Parks, Reserves and Open Space High High High Yes

Urunga Recreational Reserve Parks, Reserves and Open Space Low Low Low

Urunga Sandmass Parks, Reserves and Open Space Medium Medium Medium

Urunga Scouts - Bellinger Heads State Park Parks, Reserves and Open Space #N/A High High Yes

Yellow Rock Road - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low

Yellow Rock Road Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Public Recreation Land Parks, Reserves and Open Space Medium Medium Medium

Natural Assets

Foredune Beach and Dunes Low Low Low

Hind Dune Beach and Dunes Low Low Low

North Hungry Head Beach Beach and Dunes Low Low Low

Coastal Saltmarsh EEC Ecological Community High High High Yes

Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes

Littoral Rainforest EEC Ecological Community Extreme Extreme Extreme Yes

Mangrove Ecological Community Medium Medium Medium

Sub-tropical Coastal Floodplain Forest EEC Ecological Community Extreme Extreme Extreme Yes

Swamp Oak Floodplain Forest EEC Ecological Community Medium Medium Medium

Swamp Sclerophyll Forest EEC Ecological Community Extreme Extreme Extreme Yes

Environmental Conservation Environmental Protection Zone Medium Medium Medium

Environmental Management Environmental Protection Zone Medium Medium Medium

Heritage

Ellis Timber Mill Heritage (Archaeology Sites) Low Low Low

Former Urunga Bridge Heritage (Archaeology Sites) Medium Medium Medium

Graves x 2, Early Urunga Cemetery Heritage (Archaeology Sites) #N/A #N/A Low

Pedestrian Footbridge Heritage (Archaeology Sites) Medium Medium Medium

Ruined Drougher Heritage (Archaeology Sites) Low Low Low

Urunga Breakwater & Training Walls Heritage (Archaeology Sites) Low Low Low

Cultural Planting Heritage (Items) Medium Medium Medium

Cultural Planting - Christian Park Heritage (Items) Medium Medium Medium

House Heritage (Items) Medium Medium Medium

Pedestrian Footbridge Heritage (Items) Medium Medium Medium

Remnant Forest Heritage (Items) Low Low Low

Remnant Native Swamp Forest Heritage (Items) Low Low Low

Urunga Breakwater & Training Walls Heritage (Items) Low Low Low

Urunga Golf Club Heritage (Items) Medium Medium Medium

Urunga Recreational Reserve Heritage (Items) Low Low Low

Waterways

Bellinger River Waterway Low Low Low

Kalang River Waterway Low Low Low

Urunga Lagoon Waterway Low Low Low

RALEIGH Town Centre, Residential and Rural Property

Residential - Gordon Rd Residential Property #N/A #N/A Medium

Residential - Gurney St Residential Property #N/A #N/A Low

Residential - Old Pacific Highway Residential Property High High High Yes

Residential - Old Pacific Hwy Residential Property High High High Yes

Residential - Waterfall Way Residential Property Low Medium Medium

Rural - North Bank Rd Rural Property High High High Yes

Rural - Cabans Road Rural Property #N/A #N/A Low

Rural - McBaron Rd Rural Property #N/A #N/A Low

Rural - Waterfall Way Rural Property High High High Yes


Raleigh Industrial Estate General Industrial Zone #N/A Low Medium

Primary Production - Brutons Rd Primary Production Low Medium Medium

Primary Production - Cabans Rd Primary Production #N/A #N/A Medium

Primary Production - Elizabeth St Primary Production #N/A #N/A Low

Primary Production - Gordon Rd (Lot 1) Primary Production #N/A #N/A Medium

Primary Production - Gurney St Primary Production #N/A #N/A Low

Primary Production - Keevers Dr Primary Production High High High Yes

Primary Production - McBaron Rd Primary Production #N/A #N/A Low

Primary Production - North Bank Rd Primary Production High High High Yes

Primary Production - Old Ferry Rd Primary Production High High High Yes

Primary Production - Old Pacific Hwy Primary Production #N/A #N/A Medium

Primary Production - Pacific Hwy Primary Production High High High Yes

Primary Production - Perrys Rd Primary Production High High High Yes

Primary Production - Public Road Primary Production High High High Yes

Primary Production - Queen St Primary Production High High High Yes

Primary Production - Short Cut Road Primary Production #N/A #N/A Medium

Primary Production - Valery Rd Primary Production High High High Yes

Primary Production - Victor St Primary Production #N/A #N/A Low

Primary Production - Walter St Primary Production #N/A #N/A Low

Primary Production - Waterfall Way Primary Production High High High Yes

Primary Production - Yellow Rock Rd Primary Production High High High Yes


Pacific Hwy Major Road Extreme Extreme Extreme Yes

Alice St Minor Road #N/A #N/A Low

Brutons Rd Minor Road #N/A Low Medium

Elizabeth St Minor Road #N/A #N/A Low

Gurney St Minor Road High High High Yes

Keevers Dr Minor Road High High High Yes

Mylestom Dr Minor Road High High High Yes

North Bank Rd Minor Road Medium Medium Medium

North St Minor Road #N/A #N/A Medium

Old Coast Rd Minor Road Medium Medium Medium

Old Pacific Hwy Minor Road High High High Yes

Pacific Hwy Minor Road High High High Yes

Queen St Minor Road High High High Yes

River St Minor Road High High High Yes

Short Cut Rd Minor Road #N/A #N/A Medium


Valery Rd Minor Road High High High Yes

Victor St Minor Road #N/A #N/A Low

Walter St Minor Road #N/A #N/A Low

Yellow Rock Rd Minor Road High High High Yes

North Coast Railway Railway Extreme Extreme Extreme Yes

Services

Raleigh Waste Management Centre Waste Management Services #N/A #N/A High Yes

Private Pumping Main Sewer Services Extreme Extreme Extreme Yes



Water Line - Reticulation Main Water (Mains) Services Medium Medium Medium

Water Line - Transfer Main Water (Mains) Services Medium Medium Medium

Community Assets

Raleigh Anglican Church (& Cultural Planting Heritage) Community Buildings #N/A #N/A Low

Raleigh Primary School (& Cultural Planting Heritage) Community Buildings #N/A #N/A Low

Bellingen Coast Regional Crown Reserve Parks, Reserves and Open Space Medium Medium Medium


Yellow Rock Road Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Natural Assets




Lowland Rainforest on Floodplain EEC Ecological Community Extreme Extreme Extreme Yes






Heritage

Kelly's Cow Bails Heritage (Archaeology Sites) Medium Medium Medium

Raleigh Butter Factory Heritage (Archaeology Sites) Medium Medium Medium

Silo Heritage (Archaeology Sites) #N/A Medium Medium


Yellow Rock Aboriginal Mission Cemetery Heritage (Archaeology Sites) Medium Medium Medium

Youngs Graves - Prince of Peace Courtyard Heritage (Archaeology Sites) #N/A #N/A Low

Anglican Church Heritage (Items) #N/A #N/A Low

Cultural Planting - 'Bonnie Doon' Heritage (Items) Medium Medium Medium

Cultural Planting - 'Greenlands' Heritage (Items) #N/A Low Low

Former Post Office Heritage (Items) #N/A #N/A Medium

House Heritage (Items) High High High Yes

Multiple Items (Farmhouse etc) Heritage (Items) High High High Yes

Osprey Nest Sites Heritage (Items) Low Low Low

Scenic View, Bellinger River bank Heritage (Items) Medium Medium Medium

Urunga Breakwater & Training Walls Heritage (Items) Low Low Low

Windbreak Heritage (Items) Medium Medium Medium

Waterways


Boggey Creek Waterway Low Low Low


MYLESTOM Town Centre, Residential and Rural Property

Rural - Mylestom Drive Low Medium Medium

Rural - Tuckers Rock Road #N/A Medium Medium


George Street Minor Road High High High Yes




Services

Drainage Main Stormwater Services Medium Medium Medium

Water Line - Reticulation Main Water (Mains) Services Low Low Low

Community Assets

Alma Doepel Reserve Parks, Reserves and Open Space Medium Medium Medium


Bellinger Heads State Park Parks, Reserves and Open Space Medium Medium Medium

Mylestom Swimming Enclosure Public Recreation Land Low Low Low

Public Recreation Public Recreation #N/A #N/A Low

Natural Assets

Foredune Beach and Dunes Low Low Low

Hind Dune Beach and Dunes Low Low Low

Coastal Saltmarsh EEC Ecological Community Low Medium Medium




Swamp Sclerophyll Forest EEC Ecological Community #N/A Medium High Yes


Heritage


Waterways

Bellingen River Waterway Low Low Low

REPTON Town Centre, Residential and Rural Property

Residential - Mylestom Drive Residential Property High High High Yes

Residential - River Street Residential Property #N/A Low Medium

Residential Zoned Land Residential Property High High High Yes

Rural - Bailey Street Rural Property High High High Yes

Rural - Lennox Street Rural Property #N/A Low Medium

Rural - Mylestom Drive Rural Property High High High Yes

Rural - Perrys Rd Rural Property High High High Yes

Rural - River Street Rural Property #N/A Low Medium

Rural - Smiths Road Rural Property #N/A Low Medium

Rural - Tuckers Rock Road Rural Property #N/A Low Medium

Rural - Woodward Street North Rural Property #N/A #N/A Low


Primary Production - Mylestom Drive Primary Production High High High Yes


Bonville St Minor Road #N/A Low Medium

Caper St Minor Road #N/A Low Medium

Keevers Dr Minor Road High High High Yes

Lennox St Minor Road #N/A Low Medium


Raleigh St Minor Road #N/A #N/A Medium


Unnamed Road Minor Road #N/A Low Medium

Services



Community Assets


Bongil Bongil National Park Parks, Reserves and Open Space #N/A Low Low

Man Arm Creek Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium

Mylestom Drive - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium


Private Recreation Private Recreation Medium Medium Medium

Natural Assets

North Beach Beach and Dunes Low Low Low


Freshwater Wetland EEC Ecological Community #N/A Medium High Yes


Swamp Sclerophyll Forest EEC Ecological Community #N/A Medium High Yes

Environmental Management Environmental Protection Zone #N/A Low Low

Heritage

Ruined Timber Mill Heritage (Archaeology Sites) High High High Yes

Smith and Moran Timber Mill Heritage (Archaeology Sites) Medium Medium Medium

House Heritage (Items) #N/A #N/A Low

Waterways


BRIERFIELD Town Centre, Residential and Rural Property

Rural - Basin Rd Rural Landscape #N/A #N/A Low

Rural - Bowraville Rd Rural Landscape High High High Yes

Rural - Martells Rd Rural Landscape High High High Yes

Rural - Martells Road Rural Landscape Medium Medium Medium

Rural - South Arm Rd Rural Landscape High High High Yes

Rural - South Arm Road Rural Landscape High High High Yes

Rural Landscape Zoned Land Rural Landscape High High High Yes


Forestry Land Forestry Zone Medium Medium Medium

Primary Production - Bowraville Rd Primary Production High High High Yes

Primary Production - Bowraville Road Primary Production High High High Yes

Primary Production - Hains Ln Primary Production High High High Yes

Primary Production - Martells Rd Primary Production High High High Yes

Primary Production - Martells Road Primary Production High High High Yes

Primary Production - South Arm Rd Primary Production High High High Yes

Primary Production - South Arm Road Primary Production High High High Yes

Primary Production Zoned Land Primary Production High High High Yes


Bowraville Rd Minor Road High High High Yes

Martells Rd Minor Road High High High Yes

South Arm Rd Minor Road High High High Yes


Services

Drainage Main Stormwater Services Medium Medium Medium

Natural Assets


Lowland Rainforest EEC Ecological Community #N/A High High Yes

Lowland Rainforest on Floodplain EEC Ecological Community Extreme Extreme Extreme Yes


Waterways


FERNMOUNT Town Centre, Residential and Rural Property

Residential - Maydwell St Residential Property Medium Medium Medium

Residential - Old Brierfield Rd Residential Property #N/A #N/A Low

Residential - Waterfall Way Residential Property Medium Medium Medium

Residential Zoned Land Residential Property Medium Medium Medium

Rural - Sweedmans Ln Rural Landscape #N/A #N/A Low

Rural - Waterfall Way Rural Landscape High High High Yes



Forestry Land Forestry Zone #N/A #N/A Low

Primary Production - Mount St Primary Production #N/A #N/A Medium

Primary Production - Nicholson St Primary Production High High High Yes

Primary Production - Old Brierfield Rd Primary Production #N/A #N/A Low

Primary Production - Public Road Primary Production High High High Yes

Primary Production - Sweedmans Ln Primary Production #N/A Low Medium

Primary Production - Tyson St Primary Production Low Medium Medium




Waterfall Way Major Road Extreme Extreme Extreme Yes

Baker St Minor Road High High High Yes

Bell St Minor Road Low #N/A #N/A

Main St Minor Road Low #N/A Medium

Maydwell St Minor Road Medium Medium Medium

Nicholson St Minor Road High High High Yes

Sweedmans Ln Minor Road #N/A #N/A Low


Services


Community Assets

Car Park Community Facilities Low Low Low

Public Recreation Parks, Reserves and Open Space Medium Medium Medium

Natural Assets


Sub-tropical Coastal Floodplain Forest EEC Ecological Community Medium High High Yes



Environmental Management Environmental Protection Zone Low Low Low

Heritage

Remnant Forest Heritage (Items) Medium Medium Medium

Stand of River Sheoak - Along Bellinger River Heritage (Items) Medium Medium Medium

Waterways

Bellingen River Waterway Low Low Low

VALERY Primary Production, Forestry and Industry

Forestry Land Forestry Low Low Low

Natural Assets

Freshwater Wetland EEC Ecological Community High High High Yes

BELLINGEN Town Centre, Residential and Rural Property

Rural - John Glyde Road Rural Landscape Low Medium Medium

Rural - North Bank Rd Rural Landscape High High High Yes

Rural - North Bank Road Rural Landscape High High High Yes

Rural - Public Intersection Rural Landscape #N/A #N/A Low

Rural - Public Road Rural Landscape High High High Yes

Rural - Slarkes Rd Rural Landscape High High High Yes

Rural - Slarkes Road Rural Landscape High High High Yes

Rural - Wheatley Street Rural Landscape High High High Yes



Forestry Land Forestry Medium Medium Medium

Primary Production - Cahill St Primary Production High High High Yes

Primary Production - Doepel St Primary Production Low #N/A Low

Primary Production - North Bank Rd Primary Production High High High Yes

Primary Production - North Bank Road Primary Production High High High Yes

Primary Production - Public Intersection Primary Production #N/A #N/A Low

Primary Production - Public Road Primary Production #N/A Medium Medium


Primary Production - Wheatley Street Primary Production High High High Yes



Infrastructure Zoned Land Infrastructure #N/A #N/A Low

Bridge St Minor / Local Road High High High Yes

Doepel St Minor / Local Road High High High Yes

John Glyde Road Minor / Local Road High High High Yes

North Bank Rd Minor / Local Road High High High Yes

Slarkes Rd Minor / Local Road High High High Yes

Unnamed Road Minor / Local Road High High High Yes

Waterfall Way Minor / Local Road #N/A #N/A Medium

Services




Community Assets

Public Recreation Community Facilities Medium Medium Medium

Private Recreation Community Facilities Medium Medium Medium

Natural Assets


Lowland Rainforest EEC Ecological Community #N/A #N/A High Yes

Lowland Rainforest on Floodplain EEC Ecological Community #N/A #N/A Medium

Environmental Conservation Environmental Protection Zone #N/A #N/A Low

Environmental Management Environmental Protection Zone #N/A #N/A Low

Heritage

Former Bellingen Bridge Heritage (Archaeological Sites) Low Low Low

Two Farm Cottages Heritage (Items) #N/A #N/A Low

Waterways


Bellingen Shire Estuary Inundation Mapping D-3 Threatened Species Records


Appendix D Threatened Species Records



Family Species Common Name NSW Status

EPBC Status Preferred Habitat

Habitat Vulnerability

to SLR

Amphibian Crinia tinnula Wallum Froglet V,P

Found in a wide range of habitats, usually associated with acidic swamps on coastal sand plains. They occur in sedgelands, wet heathlands, paperbark swamps and drainage lines within other vegetation communities. They will also persist in disturbed areas. Breeds in swamps with permanent water as well as shallow ephemeral pools and drainage ditches.

High

Amphibian Litoria aurea Green and Golden Bell Frog

V

In NSW has been found in a wide range of water bodies except fast flowing streams. Inhabits many disturbed sites, including abandoned mines and quarries. Breeding habitat in NSW includes water bodies that are still, shallow, ephemeral, unpolluted (but the frog can be found in polluted habitats), unshaded, with aquatic plants and free of Mosquito Fish (Gambusia holbrooki) and other predatory fish, with terrestrial habitats that consisted of grassy areas and vegetation no higher than woodlands, and a range of diurnal shelter sites.

High

Amphibian Litoria booroolongensis Booroolong Frog E

The species is associated with the following vegetation associations: wet sclerophyll forests (shrubby and grassy sub-formation); dry sclerophyll forest (shrub/grass and shrubby sub-formation); grassy woodland; heathland; forested wetland; freshwater wetland; rainforest and cleared grazing land and pasture.

High

Amphibian Mixophyes iteratus Giant Barred Frog E1,P,2 E

Occurs in uplands and lowlands in rainforest and wet sclerophyll forest, including farmland. Populations have been found in disturbed areas with vegetated riparian strips on cattle farms and in regenerated logged areas. Many known habitats are the lower reaches of streams which have been affected by major disturbances such as clearing, timber harvesting and urban development in their headwaters.

High

Amphibian Mixophyes balbus Stuttering Frog V

Typically found in association with permanent streams through temperate and sub-tropical rainforest and wet sclerophyll forest, rarely in dry open tableland riparian vegetation, and also in moist gullies in dry forest

Medium

Bird Actitis hypoleucos Common Sandpiper P migratory

Utilises a wide range of coastal wetlands and some inland wetlands, with varying levels of salinity, and is mostly found around muddy margins or rocky shores and rarely on mudflats. Has been recorded in estuaries and deltas of streams, as well as on banks farther upstream; around lakes, pools, billabongs, reservoirs, dams and claypans, and occasionally piers and jetties. The muddy margins utilised by the species are often narrow, and may be steep. The species is often associated with mangroves, and sometimes found in areas of mud littered with rocks or snags.

High

Bird Anthochaera phrygia Regent Honeyeater E4A,P E

Mostly occur in dry Box-Ironbark eucalypt woodland and dry sclerophyll forest associations in areas of low to moderate relief, wherein they prefer moister, more fertile sites available, for example along creek flats, or in broad river valleys and foothills. In NSW, riparian forests containing River Oak (Casuarina cunninghamiana), and with Needle-leaf Mistletoe (Amyema cambagei), are also important for feeding and breeding.

High






to SLR

Bird Apus pacificus Fork-tailed Swift migratory

They mostly occur over dry or open habitats, including riparian woodland and tea-tree swamps, low scrub, heathland or saltmarsh. They are also found at treeless grassland and sandplains covered with spinifex, open farmland and inland and coastal sand-dunes. The sometimes occur above rainforests, wet sclerophyll forest or open forest or plantations of pines.

Medium

Bird Ardea ibis Cattle Egret P migratory

Occurs in tropical and temperate grasslands, wooded lands and terrestrial wetlands. High numbers observed in moist, low-lying poorly drained pastures with an abundance of high grass; it avoids low grass pastures. It has been recorded on earthen dam walls and ploughed fields.

High

Bird Ardea alba Great Egret migratory

Wetland habitats such as inland and coastal, freshwater and saline, permanent and ephemeral, open and vegetated, large and small, natural and artificial. These include swamps and marshes; margins of rivers and lakes; damp or flooded grasslands, pastures or agricultural lands; reservoirs; sewage treatment ponds; drainage channels; salt pans and salt lakes; salt marshes; estuarine mudflats, tidal streams; mangrove swamps; coastal lagoons; and offshore reefs.

High

Bird Ardenna pacificus Wedge-tailed Shearwater P J A pelagic, marine bird known from tropical and subtropical waters. Low

Bird Botaurus poiciloptilus Australasian Bittern E1,P E

Inhabits temperate freshwater wetlands and occasionally estuarine reedbeds. The species favours permanent shallow waters, or edges of pools and waterways, with tall, dense vegetation such as sedges, rushes and reeds on muddy or peaty substrate

High

Bird Calidris acuminata Sharp-tailed Sandpiper P migratory

Prefers muddy edges of shallow fresh or brackish wetlands, with inundated or emergent sedges, grass, saltmarsh or other low vegetation, including lagoons, swamps, lakes and pools near the coast, and dams, waterholes, soaks, bore drains and bore swamps, saltpans and hypersaline saltlakes inland. They also occur in saltworks and sewage farms. They use flooded paddocks, sedgelands and other ephemeral wetlands, but leave when they dry. They use intertidal mudflats in sheltered bays, inlets, estuaries or seashores, and also swamps and creeks lined with mangroves. They tend to occupy coastal mudflats mainly after ephemeral terrestrial wetlands have dried out, moving back during the wet season.

High

Bird Calidris ferruginea Curlew Sandpiper E1,P migratory

Mainly occur on intertidal mudflats in sheltered coastal areas, such as estuaries, bays, inlets and lagoons, and also around non-tidal swamps, lakes and lagoons near the coast, and ponds in saltworks and sewage farms. They are also recorded inland, though less often, including around ephemeral and permanent lakes, dams, waterholes and bore drains, usually with bare edges of mud or sand. They occur in both fresh and brackish waters. Occasionally they are recorded around floodwaters.

High

Bird Calyptorhynchus lathami Glossy Black-Cockatoo V,P,2

Open forest and woodlands of the coast and the Great Dividing Range. Allocasuarina littoralis and A. torulosa are important foods. Low

Bird Catharacta skua Great Skua marine Ocean Waters. Low






to SLR

Bird Charadrius leschenaultii Greater Sand-plover V,P migratory

Almost entirely coastal, inhabiting littoral and estuarine habitats. Mainly occur on sheltered sandy, shelly or muddy beaches with large intertidal mudflats or sandbanks, as well as sandy estuarine lagoons and inshore reefs, rock platforms, small rocky islands or sand cays on coral reefs. Occasionally recorded on near-coastal saltworks and saltlakes, including marginal saltmarsh, and on brackish swamps. They seldom occur at shallow freshwater wetlands.

High

Bird Coracina lineata Barred Cuckoo-shrike V,P

Rainforest, eucalypt forests and woodlands, clearings in secondary growth, swamp woodlands and timber along watercourses. Medium

Bird Daphoenositta chrysoptera Varied Sittella V,P

Inhabits eucalypt forests and woodlands, especially rough-barked species and mature smooth-barked gums with dead branches, mallee and Acacia woodland.

Low

Bird Dasyornis brachypterus Eastern bristlebird E Inhabits low dense vegetation in a broad range of habitat types including sedgeland, heathland, swampland, shrubland, sclerophyll forest and woodland, and rainforest.

High

Bird Diomedea antipodensis Albatross migratory Ocean waters. Low

Bird Diomedea dabbenena Albatross migratory Ocean waters. Low

Bird Diomedea epomophora epomophora Albatross V Ocean waters. Low

Bird Diomedea epomophora sanfordi Albatross E Ocean waters. Low

Bird Diomedea exulans antipodensis Albatross V

Ocean waters. Low

Bird Diomedea exulans exulans Albatross E Ocean waters. Low

Bird Diomedea exulans gibsoni Albatross V Ocean waters. Low

Bird Diomedea exulans (sensu lato) Albatross V Ocean waters. Low

Bird Diomedea sanfordi Albatross migratory Ocean waters. Low

Bird Diomedea sanfordi Albatross migratory Ocean waters. Low

Bird Ephippiorhynchus asiaticus Black-necked Stork E1,P

Mainly found on shallow, permanent, freshwater terrestrial wetlands, and surrounding marginal vegetation, including swamps, floodplains, watercourses and billabongs, freshwater meadows, wet heathland, farm dams and shallow floodwaters, as well as extending into adjacent grasslands, paddocks and open savannah woodlands. They also forage within or around estuaries and along intertidal shorelines, such as saltmarshes, mudflats and sandflats, and mangrove vegetation.

High






to SLR

Bird Erythrotriorchis radiatus Red Goshawk CE V

Inhabit open woodland and forest, preferring a mosaic of vegetation types, a large population of birds as a source of food, and permanent water, and are often found in riparian habitats along or near watercourses or wetlands. In NSW, preferred habitats include mixed subtropical rainforest, Melaleuca swamp forest and riparian Eucalyptus forest of coastal rivers.

Medium

Bird Esacus magnirostris Beach Stone-curlew E4A,P

Found exclusively along the coast, on a wide range of beaches, islands, reefs and in estuaries, and may often be seen at the edges of or near mangroves. They forage in the intertidal zone of beaches and estuaries, on islands, flats, banks and spits of sand, mud, gravel or rock, and among mangroves. Breed above the littoral zone, at the backs of beaches, or on sandbanks and islands, among low vegetation of grass, scattered shrubs or low trees; also among open mangroves.

High

Bird Fregetta grallaria grallaria

White-bellied storm petrel V Ocean waters. Low

Bird Gallinago hardwickii Latham's Snipe migratory

Permanent and ephemeral wetlands. They usually inhabit open, freshwater wetlands with low, dense vegetation (e.g. swamps, flooded grasslands or heathlands, around bogs and other water bodies). However, they can also occur in habitats with saline or brackish water, in modified or artificial habitats, and in habitats located close to humans or human activity.

High

Bird Gallinago megala Swinhoe's Snipe migratory

Habitat includes the dense clumps of grass and rushes round the edges of fresh and brackish wetlands. This includes swamps, billabongs, river pools, small streams and sewage ponds. They are also found in drying claypans and inundated plains pitted with crab holes.

High

Bird Gallinago stenura Pin-tailed snipe migratory

During non-breeding period the Pin-tailed Snipe occurs most often in or at the edges of shallow freshwater swamps, ponds and lakes with emergent, sparse to dense cover of grass/sedge or other vegetation. The species is also found in drier, more open wetlands such as claypans in more arid parts of species' range. It is also commonly seen at sewage ponds; not normally in saline or inter-tidal wetlands.

High

Bird Glossopsitta pusilla Little Lorikeet V,P

Forages primarily in the canopy of open Eucalyptus forest and woodland, yet also finds food in Angophora, Melaleuca and other tree species. Riparian habitats are particularly used, due to higher soil fertility and hence greater productivity.

Medium

Bird Grus rubicunda Brolga V,P

Often feed in dry grassland or ploughed paddocks or even desert claypans. Are dependent on wetlands especially shallow swamps. Medium

Bird Haematopus fuliginosus Sooty Oystercatcher V,P Nest on beaches and in estuaries and forage between the high and low water mark. High

Bird Haematopus longirostris Pied Oystercatcher E1,P Nest on beaches and in estuaries and forage between the high and low water mark. High






to SLR

Bird Haliaeetus leucogaster White-bellied sea eagle P migratory

Mostly recorded in coastal lowlands and around terrestrial wetlands in tropical and temperate regions of mainland Australia and its offshore islands. Habitats characterised by the presence of large areas of open water (larger rivers, swamps, lakes, the sea). Also occur at sites near the sea or sea-shore, such as around bays and inlets, beaches, reefs, lagoons, estuaries and mangroves. Terrestrial habitats include coastal dunes, tidal flats, grassland, heathland, woodland, forest (including rainforest) and even urban areas.

Medium

Bird Hieraaetus morphnoides Little Eagle V,P Occupies habitats rich in prey within open eucalypt forest, woodland or open woodland. Low

Bird Hirundapus caudacutus White-throated Needletail

P migratory

Almost exclusively aerial, recorded most often above wooded areas, including open forest and rainforest, and may also fly between trees or in clearings, below the canopy, but they are less commonly recorded flying above woodland). They also commonly occur over heathland but less often over treeless areas, such as grassland or swamps.

Low

Bird Hydroprogne caspia Caspian Tern P migratory

Mostly found in sheltered coastal embayments (harbours, lagoons, inlets, bays, estuaries and river deltas) and those with sandy or muddy margins are preferred. They also occur on near-coastal or inland terrestrial wetlands that are either fresh or saline, especially lakes (including ephemeral lakes), waterholes, reservoirs, rivers and creeks. They also use artificial wetlands, including reservoirs, sewage ponds and saltworks. In offshore areas the species prefers sheltered situations, particularly near islands, and is rarely seen beyond reefs.

High

Bird Irediparra gallinacea Comb-crested Jacana V,P

Inhabit permanent freshwater wetlands, either still or slow-flowing, with a good surface cover of floating vegetation, especially water-lilies, or fringing and aquatic vegetation.

High

Bird Ixobrychus flavicollis Black Bittern V,P

Inhabits both terrestrial and estuarine wetlands, generally in areas of permanent water in flooded grassland, forest, woodland, rainforest and mangroves.

High

Bird Lathamus discolor Swift Parrot E

Inhabits dry sclerophyll eucalypt forests and woodlands. It occasionally occurs in wet sclerophyll forests. Predominantly forages within habitats that have been so significantly cleared that they are classified as endangered ecological communities.

Low

Bird Lichenostomus fasciogularis Mangrove Honeyeater V,P

Primary habitat of the species is mangrove woodlands and shrublands but also range into adjacent forests, woodlands and shrublands, including casuarina and paperbark swamp forests and associations dominated by eucalypts or banksias.

High

Bird Limosa lapponica Bar-tailed Godwit P migratory

Found mainly in coastal habitats such as large intertidal sandflats, banks, mudflats, estuaries, inlets, harbours, coastal lagoons and bays. It is found often around beds of seagrass and, sometimes, in nearby saltmarsh. It has been sighted in coastal sewage farms and saltworks, saltlakes and brackish wetlands near coasts, sandy ocean beaches, rock platforms, and coral reef-flats. It is rarely found on inland wetlands or in areas of short grass, such as farmland, paddocks and airstrips.

High






to SLR

Bird Lophoictinia isura Square-tailed Kite V,P,3

Inhabits coastal and subcoastal, eucalypt-dominated open forests and woodlands, coastal heathlands, and often near openings and edges of forest.

Medium

Bird Macronectes giganteus Southern Giant Petrel E Ocean waters. Low

Bird Macronectes halli Northern Giant Petrel V Ocean waters. Low

Bird Merops ornatus Rainbow Bee-eater P migratory

Occurs mainly in open forests and woodlands, shrublands, and in various cleared or semi-cleared habitats, including farmland and areas of human habitation. Usually occurs in open, cleared or lightly-timbered areas that are often, but not always, located in close proximity to permanent water. Also occurs in inland and coastal sand dune systems, and in mangroves in northern Australia, and has been recorded in various other habitat types including heathland, sedgeland, vine forest and vine thicket, and on beaches.

Medium

Bird Monarcha melanopsis Black-faced Monarch migratory

Mainly occurs in rainforest ecosystems, including semi-deciduous vine-thickets, complex notophyll vine-forest, tropical (mesophyll) rainforest, subtropical (notophyll) rainforest, mesophyll (broadleaf) thicket/shrubland, warm temperate rainforest, dry (monsoon) rainforest and (occasionally) cool temperate rainforest.

Medium

Bird Monarcha trivirgatus Spectacled Monarch migratory Subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical moist montane forests. Medium

Bird Myiagra cyanoleuca Satin Flycatcher migratory Inhabit heavily vegetated gullies in eucalypt-dominated forests and taller woodlands, and on migration, occur in coastal forests, woodlands, mangroves and drier woodlands and open forests

Medium

Bird Ninox strenua Powerful Owl V,P,3

Inhabits a range of vegetation types, from woodland and open sclerophyll forest to tall open wet forest and rainforest. It requires large tracts of forest or woodland habitat but can occur in fragmented landscapes as well.

Low

Bird Numenius madagascariensis Eastern Curlew P migratory

Most commonly associated with sheltered coasts, especially estuaries, bays, harbours, inlets and coastal lagoons, with large intertidal mudflats or sandflats, often with beds of seagrass. Occasionally, the species occurs on ocean beaches (often near estuaries), and coral reefs, rock platforms, or rocky islets. The birds are often recorded among saltmarsh and on mudflats fringed by mangroves, and sometimes use the mangroves. The birds are also found in saltworks and sewage farms.

High

Bird Numenius phaeopus Whimbrel P migratory

Often found on the intertidal mudflats of sheltered coasts. It is also found in harbours, lagoons, estuaries and river deltas, often those with mangroves, but also open, unvegetated mudflats. It is occasionally found on sandy or rocky beaches, on coral or rocky islets, or on intertidal reefs and platforms. It has been infrequently recorded using saline or brackish lakes near coastal areas. It also used saltflats with saltmarsh, or saline grasslands with standing water left after high spring-tides, and in similar habitats in sewage farms and saltfields.

High






to SLR

Bird Numenius minutus Little Curlew migratory

Pools, river beds and water-filled tidal channels, and shallow water at edges of billabongs. The species prefers pools with bare dry mud (including mudbanks in shallow water) and they do not use pools if they are totally dry, flooded or heavily vegetated.

High

Bird Oxyura australis Blue-billed Duck V,P Prefers deep water in large permanent wetlands and swamps with dense aquatic vegetation. High

Bird Pandion cristatus Eastern Osprey V,P,3

Occur in littoral and coastal habitats and terrestrial wetlands of tropical and temperate Australia and offshore islands. Require extensive areas of open fresh, brackish or saline water for foraging. Frequent a variety of wetland habitats including inshore waters, reefs, bays, coastal cliffs, beaches, estuaries, mangrove swamps, broad rivers, reservoirs and large lakes and waterholes.

Medium

Bird Pandion haliaetus Osprey migratory

Occur in littoral and coastal habitats and terrestrial wetlands of tropical and temperate Australia and offshore islands. They are mostly found in coastal areas but occasionally travel inland along major rivers. They require extensive areas of open fresh, brackish or saline water for foraging and frequent a variety of wetland habitats including inshore waters, reefs, bays, coastal cliffs, beaches, estuaries, mangrove swamps, broad rivers, reservoirs and large lakes and waterholes.

Medium

Bird Plegadis falcinellus Glossy Ibis P migratory

Preferred habitat for foraging and breeding are fresh water marshes at the edges of lakes and rivers, lagoons, flood-plains, wet meadows, swamps, reservoirs, sewage ponds, rice-fields and cultivated areas under irrigation. The species is occasionally found in coastal locations such as estuaries, deltas, saltmarshes and coastal lagoons.

Medium

Bird Pluvialis fulva Pacific Golden Plover P migratory

Usually inhabits coastal habitats, though it occasionally occurs around inland wetlands. Occur on beaches, mudflats and sandflats (sometimes in vegetation such as mangroves, low saltmarsh such as Sarcocornia, or beds of seagrass) in sheltered areas including harbours, estuaries and lagoons, and also in evaporation ponds in saltworks. The species is also sometimes recorded on islands, sand and coral cays and exposed reefs and rocks. They are less often recorded in terrestrial habitats, usually wetlands such as fresh, brackish or saline lakes, billabongs, pools, swamps and wet claypans, especially those with muddy margins and often with submerged vegetation or short emergent grass. Other terrestrial habitats inhabited include short (or, occasionally, long) grass in paddocks, crops or airstrips, or ploughed or recently burnt areas, and they are very occasionally recorded well away from water.

High

Bird Pomatostomus temporalis temporalis

Grey-crowned Babbler (eastern subspecies) V,P

Inhabits open Box Woodlands on alluvial plains. Low

Bird Pterodroma leucoptera leucoptera Gould's Petrel E Ocean waters. Low

Bird Pterodroma neglecta neglecta Kermadec Petrel V Ocean waters. Low






to SLR

Bird Ptilinopus magnificus Wompoo Fruit-Dove V,P

Occurs in patches of subtropical rainforest and adjoining wet sclerophyll habitats but has also been recorded using single trees in farmland. Most abundant in warmer, mature rainforests dominated by Ficus spp..

Medium

Bird Ptilinopus regina Rose-crowned Fruit-Dove V,P

Occur mainly in sub-tropical and dry rainforest and occasionally in moist eucalypt forest and swamp forest, where fruit is plentiful. Medium

Bird Puffinus carneipes Flesh-footed Shearwater migratory Over continental shelves and slopes and occasionally inshore waters. Breed on islands in burrows on sloping ground in coastal forest, scrubland, shrubland or grassland.

Low

Bird Puffinus leucomelas Streaked Shearwater migratory Ocean waters, cliffs. Low

Bird Rhipidura rufifrons Rufous Fantail

Wet sclerophyll forests, often in gullies dominated by eucalypts usually with a dense shrubby understorey often including ferns. They also occur in subtropical and temperate rainforests. Occasionally occur in secondary regrowth.

Medium

Bird Rostratula australis Australian Painted Snipe E

Inhabits shallow terrestrial freshwater (occasionally brackish) wetlands, including temporary and permanent lakes, swamps and claypans. They also use inundated or waterlogged grassland or saltmarsh, dams, rice crops, sewage farms and bore drains. Typical sites include those with rank emergent tussocks of grass, sedges, rushes or reeds, or samphire; often with scattered clumps of lignum Muehlenbeckia or canegrass or sometimes tea-tree (Melaleuca). The Australian Painted Snipe sometimes utilises areas that are lined with trees, or that have some scattered fallen or washed-up timber.

High

Bird Rostratula benghalensis (sensu lato) Painted Snipe E

Inhabits shallow terrestrial freshwater (occasionally brackish) wetlands, including temporary and permanent lakes, swamps and claypans. They also use inundated or waterlogged grassland or saltmarsh, dams, rice crops, sewage farms and bore drains. Typical sites include those with rank emergent tussocks of grass, sedges, rushes or reeds, or samphire; often with scattered clumps of lignum Muehlenbeckia or canegrass or sometimes tea-tree (Melaleuca). The Australian Painted Snipe sometimes utilises areas that are lined with trees, or that have some scattered fallen or washed-up timber.

High

Bird Stagonopleura guttata Diamond Firetail V,P

Found in grassy eucalypt woodlands, including Box-Gum Woodlands and Snow Gum Eucalyptus pauciflora Woodlands. Also occurs in open forest, mallee, Natural Temperate Grassland, and in secondary grassland derived from other communities. Often found in riparian areas (rivers and creeks), and sometimes in lightly wooded farmland.

Low






to SLR

Bird Sterna hirundo Common Tern P migratory

Marine, pelagic and coastal. In Australia, they are recorded in all marine zones, but are commonly observed in near-coastal waters, both on ocean beaches, platforms and headlands and in sheltered waters, such as bays, harbours and estuaries with muddy, sandy or rocky shores. Occasionally they are recorded in coastal and near-coastal wetlands, either saline or freshwater, including lagoons, rivers, lakes, swamps and saltworks. Sometimes they occur in mangroves or saltmarsh and, in bad weather, in coastal sand-dunes or coastal embayments.

High

Bird Sternula albifrons Little Tern E1,P migratory

Inhabit sheltered coastal environments, including lagoons, estuaries, river mouths and deltas, lakes, bays, harbours and inlets, especially those with exposed sandbanks or sand-spits, and also on exposed ocean beaches. Nest on sand-spits, banks, ridges or islets in sheltered coastal environments, such as coastal lakes, estuaries and inlets, and also on wide and flat or gently sloping sandy ocean beaches, and also, occasionally, in sand-dunes. Forage in shallow waters of estuaries, coastal lagoons and lakes, frequently over channels next to spits and banks or entrances, and often close to breeding colonies. Roost or loaf on sand-spits, banks and bars within sheltered estuarine or coastal environments, or on the sandy shores of lakes and ocean beaches.

High

Bird Thalassarche bulleri Buller's Albatross

V migratory Ocean waters. Low

Bird Thalassarche cauta cauta Shy Albatross V migratory Ocean waters. Low

Bird Thalassarche cauta salvini Salvin's Albatross V migratory

Ocean waters. Low

Bird Thalassarche cauta steadi White-capped Albatross V migratory Ocean waters. Low

Bird Thalassarche cauta (sensu stricto) Shy Albatross V migratory Ocean waters. Low

Bird Thalassarche eremita Chatham Albatross

E migratory Ocean waters. Low

Bird Thalassarche impavida Campbell Albatross V migratory Ocean waters. Low

Bird Thalassarche melanophris Black-browed Albatross V migratory Ocean waters. Low

Bird Thalassarche melanophris impavida Campbell Albatross V migratory Ocean waters. Low

Bird Thalassarche salvini Salvin's Albatross V migratory Ocean waters. Low

Bird Thalassarche steadi White-capped Albatross V migratory Ocean waters. Low

Bird Tyto longimembris Eastern Grass Owl V,P,3

Found in areas of tall grass, including grass tussocks, in swampy areas, grassy plains, swampy heath, and in cane grass or sedges on flood plains. Medium

Bird Tyto novaehollandiae Masked Owl V,P,3

Eucalypt forests and woodlands on the coast. Medium

Bird Tyto tenebricosa Sooty Owl V,P,3

Occurs in rainforest, including dry rainforest, subtropical and warm temperate rainforest, as well as moist eucalypt forests. Medium






to SLR

Fish Acentronura tentaculata

marine Found on tropical inshore reefs. Also occurs in temperate waters associated with shallow sandflats in protected and somewhat silty coastal areas among sparse low plant growth and in algae on rocks.

Medium

Fish Carcharias taurus (east coast population) Grey Nurse Shark CE

Ocean Waters. Low

Fish Carcharodon carcharias Great White Shark V Ocean Waters. Low

Fish Epinephelus daemelii Black Rockcod V Ocean Waters. Low

Fish Festucalex cinctus Girdled Pipefish marine In association with seagrass, kelp, boulders, rocky reefs, rocks, shell rubble, sand, silt and mud. Medium

Fish Filicampus tigris Tiger Pipefish marine Ocean Waters. Low

Fish Heraldia nocturna Upside-down Pipefish marine Ocean Waters. Low

Fish Hippichthys heptagonus Madura Pipefish marine Ocean Waters. Low

Fish Hippichthys penicillus Beady Pipefish marine Ocean Waters. Low

Fish Hippocampus whitei White's Seahorse

marine Ocean Waters. Low

Fish Histiogamphelus briggsii Crested Pipefish


Fish Lamna nasus Porbeagal marine Ocean Waters. Low

Fish Lissocampus runa Javelin Pipefish marine Ocean Waters. Low

Fish Manta birostris Giant Manta Ray marine Ocean Waters. Low

Fish Maroubra perserrata Sawtooth Pipefish marine Ocean Waters. Low

Fish Pristis zijsron Green Sawfish V Ocean Waters. Low

Fish Rhincodon typus Whale Shark V Ocean Waters. Low

Fish Solegnathus dunckeri Duncker's Pipehorse marine Ocean waters. Low

Fish Solegnathus spinosissimus Spiny Pipehorse

marine Ocean waters. Low

Fish Solenostomus cyanopterus Robust Ghostpipefish marine Ocean waters. Low

Fish Solenostomus paegnius Rough Snout Ghostpipefish marine Ocean waters. Low

Fish Solenostomus paradoxus Ornate Ghostpipefish marine

Ocean waters. Low

Fish Stigmatopora nigra Widebody Pipefish marine Ocean waters. Low

Fish Syngnathoides biaculeatus Double-end Pipehorse


Fish Trachyrhamphus bicoarctatus Bentstick Pipefish marine Ocean waters. Low

Fish Urocampus carinirostris Hairy Pipefish marine Ocean waters. Low

Fish Vanacampus margaritifer Mother-of-pearl Pipefish marine Ocean waters. Low






to SLR

Flora Arthraxon hispidus Hairy-joing Grass V Moisture and shade-loving grass, found in or on the edges of rainforest and in wet eucalypt forest, often near creeks or swamps. Medium

Flora Cryptostylis hunteriana Leafless tongue-orchid V

Heathy woodlands, sedgelands, Xanthorrheoa spp. plains, dry sclerophyll forests (shrub/grass sub-formation and shrubby sub-formation), forested wetlands, freshwater wetlands, grasslands, grassy woodlands, rainforests and wet sclerophyll forests. Soils are generally considered to be moist and sandy, however, this species is also known to grow in dry or peaty soils.

Medium

Flora Cynanchum elegans White-flowered Wax Plant E

Occurs on a variety of lithologies and soil types, usually on steep slopes with varying degrees of soil fertility. Occurs mainly at the ecotone between dry subtropical rainforest and sclerophyll forest/woodland communities.

Low

Flora Dendrobium melaleucaphilum Spider orchid E1,P,2

Grows frequently on Melaleuca styphelioides, less commonly on rainforest trees or on rocks in coastal districts. High

Flora Marsdenia longiloba Slender Marsdenia V Subtropical and warm temperate rainforest, lowland moist eucalypt forest adjoining rainforest and, sometimes, in areas with rock outcrops. Medium

Flora Parsonsia dorrigoensis Milky Silkpod V,P E Found in subtropical and warm-temperature rainforest, on rainforest margins, and in moist eucalypt forest up to 800 m, on brown clay soils. Medium

Flora Phaius australis Lesser Swamp-orchid

Freshwater wetlands. High

Flora Streblus pendulinus Siah's Backbone E

Warmer rainforests, chiefly along watercourses. The altitudinal range is from near sea level to 800 m above sea level. The species grows in well developed rainforest, gallery forest and drier, more seasonal rainforest.

Medium

Flora Thesium australe Austral Toadflax V

Semi-parasitic on roots of a range of grass species notably Kangaroo Grass. Occurs in subtropical, temperate and subalpine climates over a wide range of altitudes on soils derived from sedimentary, igneous and metamorphic geology on a range of soils including black clay loams to yellow podzolics and peaty loams. Occurs in shrubland, grassland or woodland, often on damp sites.

Medium

Flora Tylophora woollsii E Grows in wet sclerophyll forest and rainforest Medium

Flora Zieria prostrata E Grows mainly in exposed southerly aspects on headlands in low coastal heathland or sod grassland. Low

Flora Acacia chrysotricha Newry Golden Wattle E1,P

An understorey species on rainforest edges and in wet or dry eucalypt forest in steep narrow gullies on quartzite soils. Medium

Flora Acronychia littoralis Scented Acronychia E1,P E A range of littoral rainforest communities on sand and meta-sedimentary clays, and also Brush Box wet sclerophyll forest on meta-sedimentary clays High

Flora Allocasuarina defungens Dwarf Heath Casuarina E E Grows mainly in tall heath on sand, but can also occur on clay soils and sandstone. Also extends onto exposed nearby-coastal hills or headlands adjacent to sandplains.

Medium






to SLR

Flora Hicksbeachia pinnatifolia Red Boppel Nut V,P V

Understorey tree in subtropical rainforest, regrowth rainforest, moist eucalypt forest and Brush Box forest. Grows up to 500 m altitude, sometimes extending into nearby wet sclerophyll forest with closed understorey. Usually grows on flat to gently inclined valley flats to steeply inclined slopes and on hillcrests. The soils are mostly slightly acid loams or clay loams and derived from a range of substrates particularly basalt derived soils.

Medium

Flora Macadamia integrifolia Macadamia Nut P V Subtropical rainforest and complex notophyll vineforest, at the margins of these forests and in mixed sclerophyll forest. Medium

Flora Niemeyera whitei Rusty Plum, Plum Boxwood

V,P

Rainforest and the adjacent understorey of moist eucalypt forest. Medium

Insect Phyllodes imperialis smithersi Pink Underwing Moth E

Found below the altitude of 600 m in undisturbed, subtropical rainforest. It occurs in association with the vine Carronia multisepalea, a collapsed shrub that provides the food and habitat the moth requires in order to breed.

Medium

Mammal Arctocephalus forsteri New Zealand Fur-seal V,P

The species utilises rocky habitat as breeding and haul-out sites and appears to avoid open rock platforms and sandy or pebbly beaches. Low

Mammal Arctocephalus pusillus doriferus Australian Fur-seal V,P

Prefers the rocky parts of islands. For foraging, the Australian Fur-seal prefers to utilise oceanic waters of the continental shelf and generally does not dive deeper than 150 m.

Low

Mammal Chalinolobus dwyeri Long-eared Pied Bat V

Sandstone cliffs and fertile woodland valley habitat within close proximity of each other is important. Habitat types inlcude rainforest and moist eucalypt forest habitats on other geological substrates. Requires a combination of sandstone cliff/escarpment to provide roosting habitat that is adjacent to higher fertility sites, particularly box gum woodlands or river/rainforest corridors which are used for foraging.

Medium

Mammal Dasyurus maculatus Spotted-tailed Quoll V,P E Preference for mature wet forest habitat especially in areas with rainfall 600 mm/year. Unlogged forest or forest that has been less disturbed by timber harvesting is also preferable.

Medium

Mammal Delphinus delphis Common dolphin marine Ocean Waters. Low

Mammal Eubalaena australis Southern Right Whale

E Ocean Waters. Low

Mammal Grampus griseus Risso's Dolphin

migratory Ocean Waters. Low

Mammal Lagenorhynchus obscurus Dusky Dolphin marine Ocean Waters. Low

Mammal Megaptera novaeangliae Humpback Whale V migratory marine

Ocean Waters. Low

Mammal Miniopterus australis Little Bentwing-bat V,P

Moist eucalypt forest, rainforest, vine thicket, wet and dry sclerophyll forest, Melaleuca swamps, dense coastal forests and banksia scrub. Roost in caves, tunnels, tree hollows, abandoned mines, stormwater drains, culverts, bridges and sometimes buildings during the day, and at night forage for small insects beneath the canopy of densely vegetated habitats.

Medium






to SLR

Mammal Miniopterus schreibersii oceanensis Eastern Bentwing-bat V,P

Caves are the primary roosting habitat, but also use derelict mines, storm-water tunnels, buildings and other man-made structures. Hunt in forested areas.

Medium

Mammal Mormopterus norfolkensis Eastern Freetail-bat V,P

Occur in dry sclerophyll forest, woodland, swamp forests and mangrove forests east of the Great Dividing Range. Medium

Mammal Myotis macropus Southern Myotis V,P

Generally roost in groups of 10 - 15 close to water in caves, mine shafts, hollow-bearing trees, storm water channels, buildings, under bridges and in dense foliage. Forage over streams and pools catching insects and small fish by raking their feet across the water surface.

Medium

Mammal Nyctophilus bifax Eastern Long-eared Bat V,P

Lowland subtropical rainforest and wet and swamp eucalypt forest, extending into adjacent moist eucalypt forest. Coastal rainforest and patches of coastal scrub are particularly favoured.

High

Mammal Orcinus orca Killer Whale migratory Ocean waters. Low

Mammal Petaurus australis Yellow-bellied Glider V,P

Inhabits tall open forest on the western fringe of the Wet Tropics Heritage Area. Floristics of the forest may vary from one location to another but the presence of two eucalypt species, Eucalyptus resinifera and Eucalyptus grandis, is essential. These occur most commonly in the wetter areas of the open eucalypt forest.

Low

Mammal Petaurus norfolcensis Squirrel Glider V,P

Inhabits mature or old growth Box, Box-Ironbark woodlands and River Red Gum forest west of the Great Dividing Range and Blackbutt-Bloodwood forest with heath understorey in coastal areas. Prefers mixed species stands with a shrub or Acacia midstorey.

Medium

Mammal Petrogale penicillata Brush-tailed Rock-wallaby V

Prefers rocky habitats, including loose boulder-piles, rocky outcrops, steep rocky slopes, cliffs, gorges and isolated rock stacks. Low

Mammal Phascogale tapoatafa Brush-tailed Phascogale V,P

Prefer dry sclerophyll open forest with sparse groundcover of herbs, grasses, shrubs or leaf litter. Also inhabit heath, swamps, rainforest and wet sclerophyll forest.

Medium

Mammal Phascolarctos cinereus Koala V,P V Inhabits eucalypt forest and woodland. High

Mammal Potorous tridactylus tridactylus Long-nosed Potoroo V

Can be found in wet eucalypt forests to coastal heaths and scrubs. Main habitat factors are dense vegetation for shelter and the presence of an abundant supply of fungi for food.

Medium

Mammal Pseudomys novaehollandiae New Holland Mouse V

Found from coastal areas and up to 100 km inland on sandstone. The species has been recorded from sea level up to around 900 m above sea level. Occurs in open heathland; open woodland with a heathland understorey and vegetated sand dunes.

Medium

Mammal Pteropus poliocephalus Grey-headed Flying-fox V,P V

Requires foraging resources and roosting sites. It is a canopy-feeding frugivore and nectarivore, which utilises vegetation communities including rainforests, open forests, closed and open woodlands, Melaleuca swamps and Banksia woodlands. It also feeds on commercial fruit crops and on introduced tree species in urban areas.

Medium






to SLR

Mammal Scoteanax rueppellii Greater Broad-nosed Bat V,P

Utilises a variety of habitats from woodland through to moist and dry eucalypt forest and rainforest, though it is most commonly found in tall wet forest. Usually roosts in tree hollows, it has also been found in buildings.

Medium

Mammal Sousa chinensis Indo-pacific Humpback Dolphin


Mammal Stenella attenuata Spotted Dolphin marine Ocean waters. Low

Mammal Tursiops aduncus Indian Ocean Bottlenose Dolphin marine Ocean waters. Low

Mammal Tursiops truncatus s. str. Bottlenose Dolphin marine Ocean waters. Low

Mammal Vespadelus troughtoni Eastern Cave Bat V,P

A cave-roosting species that is usually found in dry open forest and woodland, near cliffs or rocky overhangs; has been recorded roosting in disused mine workings, occasionally in colonies of up to 500 individuals. Occasionally found along cliff-lines in wet eucalypt forest and rainforest.

Low

Mammal Balaenoptera acutorostrata Minke Whale


Mammal Balaenoptera edeni Bryde's Whale E marine Ocean Waters. Low

Mammal Balaenoptera musculus Blue Whale E marine Ocean Waters. Low

Mammal Calonectris leucomelas Streaked Shearwater migratory Ocean Waters. Low

Mammal Caperea marginata Pygmy Right Whale migratory marine

Ocean Waters. Low

Reptile Caretta caretta Loggerhead Turtle E1,P E Lays eggs on beach foredunes during summer and forages all year in marine waters.

High

Reptile Chelonia mydas Green Turtle V,P V Lays eggs on beach foredunes during summer and forages all year in marine waters. May occur in estuaries during warmer months. High

Reptile Eretmochelys imbricata Hawksbill Turtle V Beaches and ocean. High

Reptile Hoplocephalus stephensii Stephens' Banded Snake V,P

Rainforest and eucalypt forests and rocky areas up to 950 m in altitude Medium

Reptile Hydrophis elegans Elegant seasnake marine Ocean Waters. Low

Reptile Natator depressus Flatback Turtle V Ocean Waters. Low

Reptile Pelamis platurus Yellow-bellied Seasnake marine Ocean Waters. Low

Reptiles Dermochelys coriacea Leatherback Turtle V Beaches and ocean. High

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