Lake Cathieerosionatcathie.yolasite.com/resources/Lake Cathie... · 2012. 9. 8. · Project Name:...

Lake Cathie

Coastline Management Study – Stage 2

2 April 2012 3001464

Project Name: Lake Cathie Coastline Management Study - Stage 2

Project Number: 3001464

Report for: Port Macquarie-Hastings Council

PREPARATION, REVIEW AND AUTHORISATION

Revision # Date Prepared by Reviewed by Approved for Issue by

Draft 11/10/2011 H Nelson D Messiter

Final Draft 15/11/2011 H Nelson D Messiter

Final Draft rev2

17/11/2011 H Nelson D Messiter Not for distribution

Final 02/04/2012 H Nelson D Messiter D Messiter

ISSUE REGISTER

Distribution List Date Issued Number of Copies

Port Macquarie-Hastings Council: 02/04/2012 1 electronic

SMEC staff:

Associates:

Newcastle Office Library:

SMEC Project File:

SMEC COMPANY DETAILS

SMEC Australia

74 Hunter Street, Newcastle

PO Box 1346, Newcastle, NSW 2300

Tel: 02 4925 9600

Fax: 02 4925 3888

Email: [email protected]

www.smec.com

The information within this document is and shall remain the property of SMEC Australia

Lake Cathie Coastline Management Study – Stage 2 3001464 | Revision No. 3| Page | i

TABLE OF CONTENTS

1 INTRODUCTION 1

1.1 Background 1

1.2 Study Area 1

1.2.1 Beach and Estuary 1

1.2.2 Anthropogenic Changes 3

1.2.3 Zoning and Planning Controls 3

1.2.4 Population and Visitation 4

1.2.5 Key Values and Features 5

2 COASTAL PROCESSES AND HAZARDS 6

2.1 Coastal Processes 6

2.2 Coastal Hazards 7

2.3 Assets at Risk 8

3 COASTAL MANAGEMENT PRINCIPLES 10

4 PLANNED RETREAT OPTIONS TO AVOID RISKS 12

4.1 Services Relocation 12

4.2 Development Controls 13

4.3 Voluntary Purchase 15

4.4 Acquisition and Rezoning 16

4.5 Potential Impacts 18

5 ASSET PROTECTION OPTIONS TO MITIGATE RISKS 20

5.1 Beach Nourishment 20

5.1.1 Description of Works and Estimated Costs 21

5.1.2 Potential Impacts 23

5.1.3 Development Controls 24

5.2 Revetment 25




5.3 Groyne 27




6 FUNDING SOURCES 31

6.1 Funding Assistance 31

6.1.1 NSW Government Grant Programs 31

Lake Cathie Coastline Management Study – Stage 2 3001464 | Revision No. 3| Page | ii

6.1.2 Commonwealth Government Grant Programs 31

6.2 Levies 32

6.2.1 Special Rates 32

6.2.2 Coastal Protection Services Charge 32

7 OPTIONS ASSESSMENT 33

7.1 Assumptions 33

7.1.1 Property Values 33

7.1.2 Beach Value 34

7.1.3 Asset Protection Option Costs 34

7.1.4 Benefit-Costs and NPV Analysis 35

7.2 Funding Scenarios 38

8 CONCLUSIONS 41

8.1 Effectiveness of Options in relation to Risk Management 41

8.1.1 Planned Retreat 41

8.1.2 Beach Nourishment 41

8.1.3 Revetment 42

8.1.4 Groyne 42

8.2 Approvals and Public Funding Considerations 42

9 RECOMMENDATIONS 44

9.1 Risk Management Strategy 44

9.2 General Coastal Zone Management 44

10 REFERENCES AND BIBLIOGRAPHY 46

TABLES

Table 2.1 Long-Term Shoreline Recession due to Sediment Loss and Sea Level Rise

Table 2.2 Assets at Risk in the event of a Major Storm

Table 4.1 Estimates of Compensation Payable

Table 7.1 Summary of Costs, Benefits and Impacts

Table 7.2 Assigned Private – Public Sector Contribution Percentage

Table 7.3 Assigned Private – Public Sector Contributions to Option Capital Costs

Table 7.4 Assigned Private – Council Contributions to Maintenance Costs

Lake Cathie Coastline Management Study – Stage 2 3001464 | Revision No. 3| Page | iii

FIGURES

Figure 1.1 Lake Cathie Study Area

Figure 1.2 Land Use Zoning

Figure 1.3 Coastal Erosion Map – Port Macquarie-Hastings LEP 2011

Figure 2.1 Hazard Zones

Figure 3.1 Coastal Management Principles

Figure 4.1 Coastal Hazard Planning Areas and DA Assessment

APPENDICES

APPENDIX A - DATA COLLECTION

APPENDIX B - WAVE TRANSFORATION MODELLING

APPENDIX C - HAZARD LINES

APPENDIX D - CALCULATIONS, CONCEPTS & COSTS

APPENDIX E - NET PRESENT VALUE SUMMARY

Lake Cathie Coastline Management Study – Stage 2 3001464 | Revision No. 3| Page | 1

1 INTRODUCTION

1.1 Background

The Lake Cathie Coastal Hazard Study was completed by SMEC in 2008 and was revised in 2010 to take into account the introduction of the NSW Government’s sea level rise planning benchmarks. The subsequent Stage 1 Lake Cathie Coastline Management Study (SMEC 2009) provided a preliminary assessment of 13 potential options to address coastal hazards. It was exhibited from 27 July 2009 to 7 October 2009 and a community open day was held on 18 August 2009.

At the meeting of 16 December 2009, Council adopted the Stage 1 Management Study for Lake Cathie and, following consideration of issues raised during the public exhibition period, resolved to further examine coastal management options with the preparation of a Stage 2 Coastline Management Study report for:

1. Planned Retreat

2. Beach Nourishment

3. 400 m Revetment for Illaroo Road

4. Groyne

The Stage 1 Management Study defined Planned Retreat as services relocation, development controls, voluntary purchase and property acquisition.

The detailed assessment of the four options examined in this report (Stage 2 Management Study) is based on information in the preceding reports and additional data collection (see Appendix A) and wave transformation modelling (see Appendix B). Reference is also made to a number of coastal zone management guidelines that have been released since completion of the Stage 1 Management Study, including the Guidelines for Preparing Coastal Zone Management Plans (DECCW, 2010a).

The information contained in this report, and previous studies, will provide the basis for adoption of a preferred coastline management strategy by Council for Lake Cathie. This will be documented in a subsequent Coastal Zone Management Plan (CZMP). The CZMP will also include an Emergency Action Plan (EAP).

1.2 Study Area

The southern part of Port Macquarie and the coastal townships of Lake Cathie and Bonny Hills are located along Lighthouse/ Lake Cathie/ Rainbow Beach between Tacking Point and Grants Head. Lake Cathie is located approximately 18 km by road to the south of Port Macquarie and Bonny Hills is approximately 6 km by road to the south of Lake Cathie. The lake, from which the town takes its name, is part of a wider system that includes Cathie Creek and Lake Innes to the north. Lake Cathie and the study area are shown in Figure 1.1.

1.2.1 Beach and Estuary

Lake Cathie Beach faces south-east and lies between the Lake Cathie entrance and Middle Rock Point to the south (which consists of a collection of dolerite rocks that cause a slight protrusion in the sandy beach) (Short 2007). The beach is 1.9 km long and backed by residential development along Illaroo Road and Johnathon Dixon Reserve.


Based on LiDAR data, foredune/ embankment levels at Lake Cathie are about 8 m above AHD at the southern end of Illaroo Road and around 7.5 m AHD at the northern end (note: 0.0 m AHD is approximately equal to mean sea level). Indurated sands (coffee rock) outcrop along the beach.

Lighthouse Beach lies between Lake Cathie entrance and Watonga Rocks to the north. The beach is 10.2 km long and backed by a natural foredune 10 to 20 m high, with coffee rock outcrops at the southern end.

Lake Cathie is an intermittently closed and open coastal lake or lagoon (ICOLL). The entrance area is approximately 250 m wide, with a sand flat of variable width (depending on entrance conditions) adjacent to the southern shore. When the lake closes, the beach berm at the entrance typically builds to around 2.5 m AHD. Northward migration of the entrance channel is constrained by underlying coffee rock.

The Lake Cathie/ Lake Innes catchment area is 92 km2 (NSW Public Works 1992). Only 6% of the catchment drains to Lake Cathie (WMA (1994) cited in BMT WBM (2011)). Lake Cathie is very shallow (bed level mostly above mean sea level) which means that when the entrance is open, extensive areas are exposed at low tide. Cathie Creek is approximately 40 m wide and about 2 m deep at low tide.

Figure 1.1 Lake Cathie Study Area


1.2.2 Anthropogenic Changes

Settlement of the Lake Cathie-Bonny Hills area dates from the late 1800s but significant development did not occur until the 1930s (id Consulting 2008). Lake Innes was originally a separate freshwater system, the largest in NSW (NPWS 1999). In 1933, a drain was excavated to connect Lake Innes to Cathie Creek. The drain subsequently widened and deepened under flood and tidal flows, with Lake Innes converting to an estuarine system.

Sand mining occurred during the 1950s and 1960s in the northern part of Lighthouse Beach (PWD 1991). Substantial growth also took place in Lake Cathie-Bonny Hills during this time, especially in the northern area, following construction of the first bridge across the estuary (id Consulting 2008). Since at least the 1960s, Lake Cathie has been mechanically opened to reduce the potential for localised flooding and to increase tidal exchange for water quality purposes. Rock dumping for bank protection along the southern side of the Lake Cathie entrance has also been undertaken since the late 1960s (PWD 1990). In the early 1970s a causeway and culvert (part of Kenwood Drive) were constructed across Lake Cathie. The lake entrance has been dredged in the past, with the most recent dredging being in 1995 and 2005.

1.2.3 Zoning and Planning Controls

Under the Port Macquarie-Hastings (PMH) Local Environmental Plan (LEP) 2011, coastal reserves at Lake Cathie are zoned E2 Environmental Conservation (including Johnathon Dixon Reserve), with areas of lake foreshore around the entrance and east of the Ocean Drive Bridge zoned RE1 Public Recreation. The bed of Lake Cathie, Cathie Creek and Lake Innes are zoned E1 National Parks and Nature Reserves (located within Lake Innes Nature Reserve). The entrance of Lake Cathie east of the bridge is zoned W2 Recreational Waterways as shown in Figure 1.2.

Figure 1.2 Land Use Zoning


The Lake Cathie foreshore south of the lake entrance is included in the PMH LEP Coastal Erosion Map (see Figure 1.3), which means development in this area is subject to additional LEP controls and is excluded from State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 (Codes SEPP). Information has been included on Section 149 planning notices that these lots may be affected by coastal hazards.

Figure 1.3 Coastal Erosion Map – Port Macquarie-Hastings LEP 2011

1.2.4 Population and Visitation

Lake Cathie-Bonny Hills had an estimated population of 6,187 in 2010, based on population forecasts (id Consulting 2011).

Although there is no visitation data for Lake Cathie-Bonny Hills, the total number of visitors to the Greater Port Macquarie region over the year to December 2010 was approximately 1,649,000 persons, representing a significant annual increase of 336,000 visitors, or 25.6% from the previous year. TRA (2009) found that Lake Cathie was one of the three most popular stopping places for shoulder and low season visitors to Greater Port Macquarie. It is estimated that approximately 10,000 people visit Lake Cathie Beach per annum (based on records by Council’s surf life savers).


1.2.5 Key Values and Features

Lake Cathie natural and socio-economic values and recreational opportunities include:

� Endangered Ecological Communities (EEC), listed under the NSW Threatened Species Conservation (TSC) Act 1995, i.e:

- Littoral Rainforest (also listed under the Commonwealth’s Environment Protection and Biodiversity Conservation Act (EPBC) Act 1999) around Middle Rock and is mapped under SEPP No 26 – Littoral Rainforest.

- Coastal Saltmarsh which covers much of the area surrounding the lake waterbody, as well as the margins of Cathie Creek – saltmarsh associated with this system is the second largest (6 km2) in NSW (PWD 1992). The estuary is also designation under SEPP No.14 – Coastal Wetlands.

- Swamp Sclerophyll Forest on low-lying areas upstream of the Ocean Drive Bridge and Swamp Oak Floodplain Forest around the perimeters of Lake Cathie and in particular immediately upstream of the Kenwood Road Bridge.

� Visual amenity - Lake Cathie is framed by a backdrop of forested hills, the tranquil waters of the lake, beach dunes including coffee rock platforms, and natural landscapes on both the northern and southern sides of the village.

� Diversity of habitats for shore and water birds (open water, sand shoals, shallow mud flats and exposed sand/ mud flats) including threatened and protected migratory species such as the Little Tern and Pied Oystercatcher.

� Seagrass meadows (Eelgrass and Paddleweed) and aquatic habitat for species of recreational and commercial value, e.g. crustaceans including school prawns, blue swimmer crabs and mud crabs and a wide variety of estuarine fish such as sea mullet, whiting, flathead and bream (BMT WBM 2011).

� Commercial fishing, mainly at ‘the drain’ which is also popular for recreational fishing, as are areas either side of Ocean Drive Bridge. Prawning when the entrance is open, at which time good gutters form either side of the entrance for beach fishing (Short 2007).

� Boating upstream of Ocean Drive Bridge - paddle craft and small power boats in deeper areas (power craft are prohibited in the entrance). A boat launching ramp is located at Jabiru Reserve on the north-western side of the Ocean Drive Bridge.

� Family orientated swimming and wading downstream of the Ocean Drive Bridge which is the most intensively used area of the lake. Swimming at the beach and surfing – the area just south of the entrance is patrolled over the Christmas school holidays. Middle Rock provides reasonable waves during east and south east swells (Short 2007).

� Walking along the beach and foreshore reserves. Beach access paths are located along the beach, with timber stairs at steeper points. Viewing platforms overlook the Lake Cathie entrance and the beach at Johnathon Dixon Reserve. Picnic areas and carparks are located at Middle Rock Point, Johnathon Dixon Reserve, Foreshore Reserve (off Ocean Drive) and Aquatic Reserve on the southern side of the entrance.

� Beach driving - 4WD access is provided just north of Dirah Street and at the end of Middle Rock Road, with vehicles permitted on the beach north of Dirah Street and south of Middle Rock subject to a Council permit (Short 2007).

� Ecotourism opportunities e.g. bushwalking, photography, bird watching, canoeing (including licensed activities in the nature reserve).


2 COASTAL PROCESSES AND HAZARDS

This Section includes a summary of coastal processes for the study area, primarily from the Hazard Study and additional numerical modelling undertaken as part of this Study. It also identifies the coastal hazards and assets at risk at Lake Cathie.

2.1 Coastal Processes

Following is a summary of coastal processes for the study area:

� Modelling indicated that the predominant nearshore wave direction is from the south-southeast quadrant with waves from this direction occurring more than 70% of the time (based on Sydney directional wave data). This suggests that net longshore sediment transport would be to the north, however modelling identified that there could be significant seasonal variations in the sediment transport direction (see Appendix B).

� Wave transformation modelling indicated a nearshore significant wave height of 1.5 to 1.9 m at Lighthouse/ Lake Cathie Beach for a 100 year Average Recurrence Interval (ARI) storm wave event from the south-east (see Appendix B for further information).

� Cross-shore sediment transport would occur during storm events, with sand moving offshore and gradually moving back onshore during calmer periods. When the lake is open, a localised shore-normal “channel” may form in the area in front of Illaroo Road (visible in the bathymetric soundings taken by Council for this study) as a result of sand being transported in an offshore direction by localised concentration of flow.

� Review of photogrammetric data in the Hazard Study (SMEC 2008) found an average historical recession rate of between 0.1 and 0.3 m/year. Recession rates measured on the southern side of the beach berm near the entrance were noted in earlier photogrammetric analysis by PWD (1990) as being potentially affected by rock protection.

� Sediment loss mechanisms at Lake Cathie may include:

- alongshore losses (e.g. more sediment moving out of the system to the north than is replaced from the south)

- offshore losses (i.e. under storm conditions sediment is transported offshore and some may not be returned to the beach during calmer conditions)

- movement of sediment into the Lake Cathie entrance and reworking of some sediment by flood tide currents so that it is transported beyond the entrance area

- past sand mining activities and aeolian losses (e.g. sand transported inland by winds, following removal of vegetation for sand mining).

� WMA (1998) identified the scour holes at the two bridges, combined with sand from the ocean entrance as the key sources of sand for the large shoals that have formed upstream of the Ocean Drive Bridge, adjacent to Jabiru Reserve (BMT WBM 2011).


The understanding of coastal processes affecting Lake Cathie is limited due to:

� A lack of local/ regional directional offshore wave data (directional wave data for this study was only available from the Sydney offshore waverider buoy as the Coffs Harbour waverider buoy was only recently upgraded to record directional wave data).

� Lack of detailed information on nearshore/ offshore bathymetry along the Lighthouse/ Lake Cathie/ Rainbow Beach embayment and hence the influence of features such as Middle Rocks and associated reef systems on local wave direction and sediment transport. Short (2007) noted that a permanent rip runs out against Middle Rock Point. This feature would also influence local wave direction and sediment transport.

� Lack of information on sediment budget, i.e. volume of sand bypassing headlands and moving into and out of the Lighthouse/ Lake Cathie/ Rainbow Beach system.

2.2 Coastal Hazards

At Lake Cathie, development most at risk is located south of the entrance along a 2 km length of beach where coastal erosion has exposed the underlying coffee rock. The Hazard Study (SMEC 2010) adopted the following parameters relating to coastal hazards:

� A design storm erosion demand (or storm bite) of 130 m3/m run of beach. This is less than the 200 to 250 m3/m storm bites which have been measured and are usually adopted for NSW open coast beaches due to the assumption that the coffee rock outcrops visible along the beach would provide some resistance to erosion).

� An average rate of sediment loss of 0.2 m/year or 1.5 m3/m run of beach per year (taking into account that some of the historical recession may be due to past sea level rise).

� The NSW Government’s sea level rise benchmarks of 0.4 m (from 1990 to 2050) and 0.9 m (from 1990 to 2100). This equates to the predicted shoreline recession distances due to sea level rise shown in Table 2.1 and average recession rates of 3.0 m3/m run of beach per year to 2050, increasing to 3.5 m3/m run of beach per year by 2100.

The distances in Table 2.1 are based on the assumption that the shoreline is comprised of erodible sediments. Mapping of coastal quaternary geology by the Department of Primary Industries (2008) indicates that development at Lake Cathie is located on marine sands and indurated sands, with the only bedrock to the south of the village, outcropping at Middle Rock (as noted in Section 1.2.1).

Table 2.1 Long-Term Shoreline Recession due to Sediment Loss and Sea Level Rise

2050 2100

Long-term recession due to sediment loss 9 m 19 m

Long-term recession due to sea level rise 17 m 42 m

Total 26 m 61 m

As shown in Table 2.1, the beach is subject to recession regardless of the postulated increase in sea level. Accordingly, the risks associated with this hazard need to be considered irrespective of shoreline recession due to sea level rise.


The parameters discussed above were used to produce the:

� present day (immediate) hazard line, i.e. position of back beach escarpment (after this has slumped to a stable angle of repose) following erosion of 130 m3/m of sand from the beach.

� 2050 and 2100 hazard lines (taking into account long-term recession and storm bite).

Taking into account dune slopes, the limit of the Zone of Reduced Foundation Capacity (ZRFC) was estimated as being 13 to 14 m landward of the zone of slope adjustment, see Figure 2.1. Following the ‘design’ storm building foundations may be located in an area subject to reduced bearing capacity. Refer to Appendix C for hazard line locations and the limit of reduced foundation capacity.

After Geomarine & Coffey Partners 1991

Figure 2.1 Hazard Zones

The maximum wave run-up level at Lake Cathie was estimated at 5.5 m AHD (SMEC 2010). As noted in Section 1.2.1, dune heights along the Lake Cathie foreshore are well above this level and hence wave overtopping and coastal inundation are not an issue for development on the open coast. However, wave overwash of the beach berm at the lake entrance would be a frequent event.

In addition to shoreline recession and a gradual ‘rolling’ back and building of dune heights, BMT WBM (2011) identified the likely implications for sea level rise on ICOLLs as follows. Sea level rise would cause ICOLL entrance sand berms to move inland and 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. Sea level rise also poses an increased threat of inundation to assets and existing development in proximity to estuary shorelines, with gravity drained stormwater infrastructure and sewerage systems likely to be compromised.

2.3 Assets at Risk

The following assets have been identified from the hazard maps (see Appendix C) as being at risk for the planning periods indicated in Table 2.2. This includes assets at risk due to wave impact and/ or coastal erosion during a major ocean storm event and, as indicated, assets that may be at risk due to reduced foundation capacity.


Table 2.2 Assets at Risk in the event of a Major Storm

Immediate Risk 2050 2100

Illaroo Road

Due to the above, vehicle access and services to 14 dwellings is at risk

Along Illaroo Road, 17 dwellings (including the eastern most lot in Bundella Avenue) may be at risk of structural damage due to reduced foundation capacity

17 dwellings along Illaroo Road and services to these dwellings

An additional dwelling on Bundella Avenue may be at risk of structural damage due to reduced foundation capacity

Around Illaroo Road including the eastern end of Bundella Avenue, an additional 15 dwellings may be at risk

Along the northern part of Chepana Street, around 40 dwellings may be at risk

The remainder of dwellings along Chepana Street may be at risk of structural damage due to reduced foundation capacity

Currently, foreshore development along Illaroo Road is a mix of: modern two storey dwellings; older style, two storey (mainly face brick) dwellings; and circa 1950s single storey cottages, most of which have timber/ fibro cladding. Dwellings include permanent residences and holiday lettings.


3 COASTAL MANAGEMENT PRINCIPLES

The Guidelines for Preparing Coastal Zone Management Plans (DECCW 2010a) set out the principles for coastal zone management, as reproduced in Figure 3.1.

Figure 3.1 Coastal Management Principles


As noted in Section 1.1, Council resolved to examine four coastal zone management options for Lake Cathie, i.e:

� Planned Retreat

� Beach Nourishment

� 400 m Revetment along Illaroo Road

� Groyne

With reference to Principle 6 in Figure 3.1, Planned Retreat can be considered an option to avoid risk. The other options can be considered options to mitigate risks. Accordingly, the discussion of options is set out under these two risk management categories. Discussion is included on uncertainties in risk prediction, and the options address the increasing risks due to shoreline recession over the adopted planning period of 50 years.


4 PLANNED RETREAT OPTIONS TO AVOID RISKS

Options to avoid risks are appropriate zoning and development controls to ensure future development is located away from areas subject to coastal processes. This means no intervention to address coastal hazards now or in the future. This approach is consistent with Ecologically Sustainable Development (ESD) Principles.

In the case of existing development, avoiding the risk would mean removing assets through voluntary purchase or acquisition. Interim measures such as servicing strategies can be developed to maximise the length of time existing uses of the coastline can continue.

4.1 Services Relocation

As noted in the Hazard Study, during site visits in 2007 significant undercutting of the coffee rock platform by wave action was occurring in some locations along Illaroo Road, which would weaken the structural integrity of the platform and could cause block failure of entire sections along joint weaknesses through the coffee rock strata. This is likely to lead to sudden failure of large areas of embankment in some areas.

Further evidence of embankment instability was evident as an area of roadway above the embankment was eroding. This would imply that there is a loss of roadway material though the embankment and that there are fractures leading directly through the coffee rock embankment and onto the beach. It is difficult to estimate the precise rate of erosion of the coffee rock and the locations in which sudden embankment failure could occur. In addition to embankment instability caused by undercutting by wave action, large scour holes were observed at the locations of stormwater outlets, which appeared to be exacerbating embankment instability (SMEC 2008).

The following interim measures could be considered to extend the length of time services are available to properties a risk:

� preparation of a servicing strategy (including access) for properties along Illaroo Road in consultation with all service providers

� shoreline monitoring/ survey of storm erosion escarpments and assessment of shoreline recovery

� when the area immediately seaward of the Illaroo Road carriageway is considered at risk of collapse:

- barricade off seaward road lane and designate road one-way traffic (depending on the stability of the remaining carriageway it may be necessary to relocate the road closer to residences and provide a shared pedestrian and resident’s vehicle only access)

- continue to monitor the situation and relocate water main to the rear of properties when necessary and make new connections

- inform other service providers (power, phone cables) that alternative measures may be required to maintain services.

The estimated capital cost to relocate access and services along Illaroo Road is around $440,000. Any costs associated with obtaining easements would be additional, however, as the work would be for the benefit of affected residents it is assumed this could be negotiated at minimal cost.


In the event that a long-term option had not been implemented and severe coastal erosion was experienced, removal or demolition of dwellings via an order under the Local Government Act 1993 may be necessary when:

� the erosion escarpment is less than 14 m from the most seaward point of a structure, i.e. the dwelling may be located within the ZRFC (demolition and removal would not be required where a suitably qualified and experienced engineer certified that the structure was not at risk); or

� the erosion escarpment has impacted on the stability of the access servicing the property (and no other access arrangements can be made); or

� services are no longer available as they have been removed by the relevant authority due to coastal erosion and no arrangements have been made for their restoration/ relocation.

4.2 Development Controls

The NSW Coastal Planning Guideline: Adapting to Sea Level Rise (DoP 2010) sets out strategies that could be employed to address coastal hazards including:

� configuring the development site layout to minimise exposure to coastal risks e.g. ensuring that buildings and infrastructure are placed in low risk areas on the site and provide open space and landscaping between buildings and areas of higher hazard risk

� constructing buildings or structures that are easily decommissioned, disassembled or relocatable either on-site or off-site as required

� providing for safe exit routes during storm events.

It should be noted that in some instances a site may be deemed unsuitable for further development, as illustrated in the guideline and reproduced in Figure 4.1 and time and/ or ‘trigger’ limited development consent conditions could be applied to allow ongoing sustainable use of coastal areas until such time as coastal risks threaten life and property.

Figure 4.1 Coastal Hazard Planning Areas and DA Assessment


A suggested trigger distance is based on the ZRFC and the assumption that the dune down to the design storm scour level is comprised of erodible material (e.g. sand). As noted in Section 2.2 the distance from the top of the erosion escarpment to the most seaward point of a structure (trigger distance) indicates when a structure may become at risk from foundation failure. Refer to Figure 2.1 which illustrates the ZRFC.

It should be noted that the ZRFC varies in response to dune height and sand/ soil properties. Existing foundations (e.g. piles) may be founded below the ZRFC and so the associated structure may remain stable, however, piles may not necessarily have been designed to withstand wave impact. Accordingly, site specific conditions and foundation design need to be taken into account in an assessment of structural stability. In addition, the likely recovery of the beach following a major storm, or series of storm events, also needs to be considered. A review of photogrammetry showed the beach berm was significantly eroded following coastal storms in mid 2007, however, four months later considerable recovery had occurred. An assessment of likely beach recovery can be made based on professional coastal engineering judgement with reference to net sediment loss and escarpment height.

The understanding of local coastal processes will improve as further data on wave climate, sediment budget, sea level rise and shoreline response to sea level rise becomes available. Accordingly, the hazard lines will be revised periodically. In addition, over time, the hazard lines will ‘roll’ landward as shoreline recession is realised.

As noted in Section 1.2.3, areas included on the PMH LEP Coastal Erosion Map are excluded from the Codes SEPP 2008. This means development of minimal environmental impact covered by the Codes SEPP (such as decks and carports) would require consent in areas potentially affected by coastal erosion.

The PMH LEP already contains provisions for areas affected by coastal erosion, in accordance with the Standard Instrument—Principal Local Environmental Plan, which is the current template for all NSW LEPs. Relevant clauses from the LEP and associated PMH Development Control Plan (DCP) 2011 are reproduced below. An example of additional DCP provisions, based on those proposed by Greater Taree City Council for a planned retreat strategy (WorleyParsons 2011), are shown in italics.

PMH LEP 2011 Clause 7.6 (3):

Development consent must not be granted to development on land to which this clause applies [shown on the Coastal Erosion Map] unless the consent authority has considered whether the development:

(a) will significantly adversely affect coastal hazards, and

(b) will result in significant detrimental increases in coastal risks to other development or properties, and

(c) will significantly alter coastal hazards to the detriment of the environment, and

(d) incorporates appropriate measures to manage risk to life from coastal risks, and

(e) avoids or minimises exposure to coastal hazards, and

(f) makes provision for relocation, modification or removal of the development to adapt to coastal hazards and sea level rise planning benchmarks for New South Wales.

PMH DCP 2011 Clause DP8.1:

� Development identified within a coastal erosion hazard area complies with clause 7.6 of the Port Macquarie-Hastings LEP 2011



� Development must be in accordance with the applicable Coastal Zone Management Plan and take into account the identified hazard lines.

� Subdivision of land to create separate additional dwelling entitlements will not be approved.

� Only one dwelling to be permitted on each separate lot (i.e. no dual occupancies etc).

� Development is not permitted seaward of the immediate hazard line.

Seaward of 2050 hazard line:

� For the purposes of Clause 7.6 (3) (f) the trigger for relocation, modification or removal of development fronting Illaroo Road at Lake Cathie is:

- where the erosion escarpment is less than 14 m from the most seaward point of a structure (demolition and removal is not required where a suitably qualified and experienced engineer can certify that the structure is not at risk); or

- where the erosion escarpment has impacted on the stability of the public roadway servicing the property (and no other access arrangements can be made); or

- services are no longer available as they have been removed by the relevant authority due to coastal recession.

� Additions and alterations – unless the additions or alternations are relocatable and/ or demountable, the maximum size of any addition or alteration is 10% or 30 m2, whichever is the lesser of the original approved development.

� All approvals will include a condition of consent requiring removal of structures if the trigger above occurs.

� Development applications will also need to include a suitable relocation strategy.

4.3 Voluntary Purchase

Properties affected by coastal hazards could be purchased as they are offered for sale on the open market, or if an owner voluntarily offered to sell their property to Council or the State Government. Although voluntary purchase has been proposed in past coastal zone management plans in reality, purchase of properties at risk has usually occurred through rezoning and acquisition (including for open space), or purchase on the open market. For example, voluntary purchase was included in the 1997 Wooli Coastline Management Plan but no property owners had approached Clarence Valley Council to purchase their property in the period prior to review of the Plan in 2010.

From a review of realestate.com.au in August 2011, the average asking price of ten properties for sale along Illaroo Road and the seaward side of Chepana Street was about $580,000, with discounting averaging 6.3%.

The properties for sale represented a mix of dwellings:

� 2 x 2 bedroom cottages

� 2 x 3 bedroom houses

� 4 x 4 bedroom houses

� 1 x 5 bedroom house

� 1 block of four apartments (5 bedrooms in total)


Based on this information, the estimated average market value of beachfront houses at Lake Cathie is about $550,000 (taking into account the 6.3% discounting). In relation to Illaroo Road (which enjoys water views), Council’s consultant valuer provided general information on 2011 market values for various styles of property. Based on this information, the 2011 market value of the 17 properties along Illaroo Road affected by the immediate hazard line was estimated at about $10.5 M (or an average of around $600,000 per property).

Council’s consultant valuer noted that market values were higher around 2004 due to the effects of the property boom along the mid north coast, with the market at present depressed.

The 2009 Valuer General’s land valuation for the 17 properties along Illaroo Road was $6.2 M. Although land valuations do not include the value of dwellings or other improvements, they are based on inspections and analysis of a large number of sales in a locality to gain an in-depth understanding of what is happening in the real estate market. During the valuation process, the valuer examines both vacant land and improved property sales. When comparing property sales to the land being valued, the valuer may take a number of factors into consideration such as amenities and town planning controls and constraints on use (www.lpi.nsw.gov.au).

Accordingly, beachfront land values would be expected to decline over time as coastal erosion and recession are experienced as this would impact on access and re-development potential. Council’s consultant valuer noted that currently this factor is estimated to have reduced market values by 15-20%.

4.4 Acquisition and Rezoning

As shown in Figures 1.2 and 1.3, the properties along Illaroo Road affected by the immediate hazard line are in an area zoned R1 General Residential. The foreshore either side is zoned E2 Environmental Conservation. Lots along Illaroo Road could be rezoned to a more appropriate land use zone either before or after acquisition.

Council (or the Minister for Planning) can rezone land through the plan-making provisions of Part 3 of the Environmental Planning and Assessment (EP&A) Act. To initiate this process, Council’s resolution to prepare a draft LEP is first forwarded to the Department of Planning (DoP) as a planning proposal. The DoP Director General decides whether the proposal should proceed, whether a local environmental study is required and/ or stipulates any specific matters that need to be addressed in preparing the draft plan (DoP 2010). If the planning proposal is to proceed, the plan is drafted and, following consultation, the Minister for Planning decides whether or not to ‘make’ the plan. Community consultation as part of this process includes receiving and considering submissions and may also include a public hearing.

Environment protection zones include E3 Environmental Management and E4 Environmental Living, which permit dwelling houses and a range of other uses with consent. To avoid future risks, dwelling houses would need to be prohibited under the zoning (e.g. E2 Environmental Conservation).

In the case of rezoning from residential use to ‘environment protection’, owners are likely to experience ‘hardship’ as it may be more difficult for the owner to sell, or to sell at the former market value due to development constraints. In this case, the owner could make an application for Council to acquire the land.

The Land Acquisition (Just Terms Compensation) Act 1991 (referred to from here on as the Land Acquisition Act) applies to the acquisition of land that is permitted under another Act. Different provisions apply depending on whether acquisition is by private agreement


or the compulsory process. In addition to the acquisition of land, the Land Acquisition Act applies to acquiring an interest in land, e.g. an easement.

The compulsory acquisition of land can only be made under the Local Government Act 1993 and the Roads Act 1993. Under Section 186 of the Local Government Act 1993, Council can only acquire land for the purpose of exercising its functions. This includes the acquisition of land that is to be made available for any public purpose for which it is reserved or zoned under an environmental planning instrument, or land which forms part of, or adjoins or lies in the vicinity of, other land proposed to be acquired.

Under the Local Government Act 1993 (Chapter 6), Council’s functions include:

� recreational facilities

� environment conservation, protection and improvement services and facilities

� water, sewerage and drainage works and facilities

� storm water drainage and flood prevention, protection and mitigation services and facilities

� tourism development and assistance.

Councils also have service functions under other Acts. For example, Council has functions relating to the provision and management of roads under the Roads Act 1993. Section 177 of the Roads Act 1993 allows Council (as a roads authority) to acquire land for any of the purposes of that Act.

The decision to acquire land is made through a formal Council resolution. If Council resolves to acquire land by private agreement the process does not need to follow that applying to compulsory acquisition, however, the compensation provisions of the Land Acquisition Act still apply.

In the case of owner-initiated acquisition, under the PMH LEP (Clause 5.1), Council would be required to acquire the land in most instances apart from land zoned for the following purposes where the relevant State Government authority would be required to acquire the land:

� RE1 Public Recreation and marked “Regional Open Space”

� SP2 Infrastructure and marked “Classified Road”

� Zone E1 National Parks and Nature Reserves and marked “National Park”

� R1 General Residential and marked “School”.

When acquisition is owner-initiated, the land does not have to be acquired within the stipulated period under the Land Acquisition Act. In addition, the land may be used for any purpose with consent, before it is used for the purpose for which it is reserved. Accordingly, the land could still be used for residential purposes and dwellings could be leased out.

An application for compulsory acquisition must include the Council’s reasons for acquiring the land by the compulsory process instead of by agreement, including actions taken to acquire the land by agreement, submissions by the landowner and evidence of negotiations. Upon approval by the Minister for Local Government and the Governor, pre-acquisition procedures can begin. This includes a notice to the owners, which includes the period within which the land will be compulsorily acquired. In cases where acquisition is not owner-initiated, the land must be acquired in 90 to 120 days after giving notice.


Upon gazettal, Council obtains a freehold interest in the land and a compensation notice is issued to the former owner of land that includes an offer to pay a specified amount of compensation as determined by the Valuer-General. The owner has the right to object to the amount offered.

The previous owner is also entitled to occupy the property on a rental basis (if it is his/ her principal place of residence or place of business) for three months after it is compulsorily acquired (between 90 and 120 days after giving notice),.

The Land Acquisition Act sets out compensation items. Associated costs for the 17 properties affected by the immediate hazard line are provided in Table 4.1. The costs below are for estimated current market value and 2009 land value. The current maximum non-financial disadvantage cost set out under the Act for property acquisition is $15,000. This relates to compensation for disadvantage resulting from the necessity of a person to relocate his or her principal place of residence. Legal and financial costs are estimated at $5,000 per property.

Although not all properties along Illaroo Road are the owner’s principal place of residence (as noted in Section 2.3), non-financial disadvantage for all properties has been included for the purposes of costing this option.

Table 4.1 Estimates of Compensation Payable

Item $ Cost for 17 Properties

Non-financial disadvantage 255,000

Legal and financial costs 85,000

Stamp duty on purchasing land of the same value 202,555

Stamp duty on purchasing land and a dwelling of similar value 344,080

Total 886,635

Taking into account the compensation payable, costs associated with compulsory acquisition would be:

� $11.18 M based on current estimated market value

� $6.75 M based on 2009 land values.

In addition to this would be demolition costs, estimated at $260,000, based on Rawlinsons (2011).

4.5 Potential Impacts

Impact on Coastal Processes, Beach Amenity and Public Access

For services relocation, impacts on coastal processes would be confined to where existing structures interact with natural processes. If major coastal erosion was experienced in the near future, pedestrian access along Illaroo Road may not be possible due to safety issues. In the longer term, it may not be possible to maintain public vehicle access along Illaroo Road and visual amenity would be reduced due to debris from failed sections of the roadway (prior to removal) and barricading etc.


If development and infrastructure along Illaroo Road were removed through purchase and acquisition, natural coastal processes could be accommodated and beach amenity and access could be improved. The road reserve and cleared lots could be developed as parkland, similar to the adjoining Johnathon Dixon Reserve, or as noted below planted out with dune species.

Ecological Impacts

The dune slope adjacent to Illaroo Road contains a narrow regeneration area of coastal rosemary, coastal wattle, spiny-headed mat-rush and coastal banksia. Impacts associated with services relocation would be confined to possible replacement of vegetation (mostly turf) on the nature strip with a trafficable surface to maintain property access. A stabilised slope to the beach along the modified access would still need to be maintained and could be planted out with native dune species.

If dwellings were removed through purchase or acquisition, the road reserve and cleared lots could be planted out with native dune vegetation to provide a more stable dune system, habitat for native fauna and a wildlife corridor connecting to the vegetated dunes to the south.

Social Impacts

Relocation and modification of access and services would permit owners/ residents of existing dwellings along Illaroo Road to continue to enjoy their properties for a longer period. However, residents may suffer emotional strain due to financial and social costs such as a likely inability to sell or lease their property; the unknown time they may be able to occupy their dwelling; and the uncertainty of coastal storm impacts.

Under compulsory acquisition, social costs (e.g. psychological complaints associated with being forced to move) would still exist. However financial costs would be alleviated as residents would have access to compensation.

Information provided by Council on mailing address post codes for properties along Illaroo Road suggests that of the 17 properties affected by the immediate hazard line:

� six properties are owner occupied

� four owners live within the Hastings-Port Macquarie LGA and hence may occupy the properties permanently or on a regular basis

� one owner lives to the west of Port Macquarie

� six owners live in the Sydney/ Central coast region.

Based on this, possibly only half the affected properties are the owner’s principal place of residence. Accordingly, overall the social cost of acquisition may be less. However, some properties may be holiday lettings which would have a financial impact on individual owners, and to a lesser extent local tourism income through fewer holiday lettings and overnight visitors to the area.

If owners were considering selling, voluntary purchase and acquisition by private agreement may enable owners to purchase in areas where development is not constrained by risks associated with coastal or other natural hazards. Owners could also chose when to sell and relocate.


5 ASSET PROTECTION OPTIONS TO MITIGATE RISKS

Options to mitigate risks are those that either alter coastal processes in some way in an attempt to provide a buffer to affected properties in the event of coastal erosion (e.g. beach nourishment, with or without structures to locally contain nourishment material) or those that provide ‘terminal’ protection (e.g. revetments or seawalls which limit shoreline recession). As these engineered options would interfere locally with coastal processes they may result in unintended adverse impacts on adjacent areas of the coast and the Lake Cathie estuary, which is part of the coastal system. The magnitude of potential impacts on Lake Cathie may be influenced by:

� Past engineering works (as described in Section 1.2.2) which have altered the natural characteristics of the estuary by introducing constrictions (e.g. the bridges) and changing tidal influence (e.g. connection to Lake Innes).

� Adopted entrance management practices and proposed future works as outlined below.

Following consideration of recent investigations by BMT WBM (2011) Council resolved (amongst other matters), at the meeting of 27 July 2011, that:

� Kenwood Drive Bridge be widened as part of any future asset upgrade or replacement works.

� The current lake opening level of 1.6 m AHD remain unchanged.

� Dredging works be limited to removal of sediment from the entrance downstream of the Ocean Drive Bridge.

A 50 year planning period has been adopted for the following conceptual management options based on the likely design life of groynes and revetments in the dynamic coastal environment. Development of these conceptual options took into account the following considerations:

� designs to withstand the 100 year ARI ocean storm design event (water level, wave height and period, scour level, wave run-up and other design parameters)

� acceptable damage levels during storm events

� available construction materials

� probable construction methods (which can be a determining criteria in some cases, e.g. groyne crest widths sufficient for construction vehicles)

� scour and settlement

� intent of structure (complete or partial mitigation of coastal hazards).

Conceptual designs (plan and sections) are presented for structural management options in Appendix D. Appendix D also includes information on the calculation of beach nourishment volumes.

5.1 Beach Nourishment

Beach nourishment involves importing sand to build a wider beach, thus providing improved beach amenity and coastal protection (or a buffer) to foreshore assets. Beach nourishment would not preclude the adoption of other risk mitigation options in the future and could accommodate uncertainty in risk predictions (e.g. magnitude of sea level rise and associated shoreline response). It could also be adopted as an interim risk management option or combined with other mitigation options.


5.1.1 Description of Works and Estimated Costs

As noted by BMT WBM (2011) sedimentation within the lower part of the Lake Cathie estuary is primarily associated with re-worked coastal and marine sands, with catchment sediment loads not considered significant. Accordingly, the Lake Cathie entrance has been considered as a source of beach nourishment material.

BMT WBM (2011) included a description of past dredging works which provides an indication of the volumes of material likely to be available from the entrance (downstream of the Ocean Drive Bridge) for beach nourishment. Areas upstream of the bridge have not been considered because of:

� Council’s resolution of the 27 July 2011, i.e. dredging limited to downstream of the Ocean Drive Bridge

� environmental values (e.g. seagrass beds, as noted in Section 1.2.5)

� legislative barriers to dredging (i.e. Lake Cathie and Cathie Creek are within a nature reserve subject to the provisions of the National Parks & Wildlife Act 1994).

� Sediment compatibility issues (i.e. sediments would not be entirely of marine origin).

Analysis of samples at six locations immediately upstream and downstream of the Ocean Drive Bridge collected by GHD (2004) characterised the sediments as medium grained sand, with traces of fine sand and little or no fine material (BMT WBM 2011). Analysis of sediment samples, as part of this Study, showed a median grain size of 0.38 mm on the beach berm (four sites), with some finer material (median grain size 0.23 mm) at a site on the northern side of the entrance (see Appendix A). It is likely that courser material has been deposited on the berm during wave overtopping, with finer material being transported further into the entrance. Beach sand along the NSW mid-north coast has a typical median grain size of 0.3 mm.

As noted in Section 1.2.2, dredging downstream of the Ocean Drive Bridge adjacent to the foreshore reserve was undertaken by Council in 1995 and more recently in 2005. Dredging the Lake Cathie entrance is noted in Council’s Dredging Strategy (PMHC 2007) as being a low priority site, although it may be undertaken in combination with dredging works at other sites to take advantage of economies of scale, given dredge mobilisation and demobilisation costs.

From a review of previous studies (GHD 2004, WMA 1998, WMA 1994b) and advice provided by Council, the design of past dredging works was as follows.

� In 1995 it is understood that approximately 4000 m3 of sand was removed from an entrance shoal and used to reform the beach berm to a level between 1.2 m AHD and 1.5 m AHD (thus ensuring the entrance remained closed during dredging works). The depth of excavation was generally to -0.5 m AHD or an average of around 0.7 m below the pre-existing levels – to maintain a safe (shallow) depth for wading (as noted in Section 1.2.5 the entrance is popular with families).

� Removal of sand in 2005 was undertaken by a small cutter suction dredge, with the approximate depth of dredge material removed varying between 0.4 m and 1.2 m. This resulted in the removal of some 25,000 m3 of sand which was pumped to the beach on the northern side of the entrance employing one booster pump (at a cost of approximately $10/m3).

GHD (2004) estimated that dredging would be required every 5 to 10 years. Council’s dredging strategy (PMHC 2007) indicates the dredge area within the entrance and disposal sites south and north of the entrance.


As noted in Section 2.3, Illaroo Road is at risk in the event of a major storm event(s). If the purpose of beach nourishment is to mitigate the risk to properties, sufficient volumes need to be placed on the beach to account for long-term recession due to sediment loss and sea level rise over the adopted 50 year planning period, as well as short-term losses due to storm erosion events.

Ideally the objective of beach nourishment would be to ‘move’ the present day hazard line seaward of the Illaroo Road reserve to provide some protection for the road and to provide sufficient beach width for beach amenity following a major storm event (note that there would also be recovery of the beach following a storm event). However, the volume of sand that can be dredged from the Lake Cathie entrance is limited. In addition to dredging, removal of material from the sand flat on the southern side of the entrance could be considered. It should be noted that the volume of material in this location (and the entire entrance compartment) fluctuates depending on climatic and entrance conditions.

Accordingly, other potential sand sources were identified from Council’s 2007 Dredging Strategy which includes maintenance dredging of the Camden Haven River Estuary and Hastings River Estuary. The strategy includes the likely dredging cost for individual sites but does not include dredge volumes. Assuming total costs provided in the strategy are based on dredging costs of $10/m3, around 90,000 m3 of nourishment material may be available from sites close to the Hastings River entrance (i.e. sites comprising mainly marine sands).

However, the use of sand dredged from the Hastings River for nourishment of Lake Cathie Beach would reduce sand volumes available to nourish other beaches and foreshore areas identified in Council’s Dredging Strategy, including the very popular Town Beach.

Sourcing nourishment material from the Camden Haven River was not considered because nominated dredging sites are located upstream from the entrance and therefore would not be mainly comprised of marine sediments.

Offshore marine sands were not considered due to current legislative barriers to offshore sand mining. In addition, the use of offshore sand resources for beach nourishment would only be economically feasible if undertaken on a large scale. For example, AECOM (2010) estimated a unit rate of $25/m3 for the extraction and placement of 12,000,000 m3

of offshore marine sand on 31 beaches within the Sydney basin.

Three sand volumes were considered in the assessment of beach nourishment as a management option. The first two rely on the availability of an additional nourishment sand source and are based on nourishing the beach profile to -12 m AHD. The initial and maintenance nourishment estimates below include an allowance for investigation, design, approvals and dune works.

a) To ‘move’ the present day hazard line to the seaward side of the Illaroo Road Reserve (i.e. approximately 7 m seaward of the current hazard line) would require 96,000 m3 of material initially to be placed on the beach, with 46,000 m3 of material placed on average every 10 years over the 50 year planning period. The maintenance nourishment volume covers predicted shoreline recession due to sediment loss and sea level rise which is also included in the initial nourishment volume. Based on a dredging and delivery cost of say $10/m3 from Lake Cathie and $30/m3 to supply, truck and place sand from a local sand source, this option would have an estimated initial cost of $ 2.44 M, and average 10 yearly maintenance cost of $860,000.


b) To ‘hold’ the present day hazard line at its present position (which impacts the Illaroo Road carriageway) over the 50 year planning period would involve maintenance nourishment as described above, with the initial nourishment volume equal to the maintenance nourishment volume of 46,000 m3. The cost of this option is estimated at $860,000 initially and on average every 10 years. This option would provide for one-way road access only to properties over the longer term.

c) To mitigate storm impacts using sand potentially available in the Lake Cathie entrance (taken to be approximately 30,000 m3 including some material from the sand flat) to nourish the beach would have an initial and ongoing maintenance cost every 10 years of $380,000.

Refer to Appendix D for beach nourishment calculations and a breakdown of cost estimates. The volumes above assume that the nourishment source has the same characteristics as the native beach sand. As noted earlier, some finer material was identified along Foreshore Reserve. If the nourishment source comprised finer sands, a higher volume would be required to achieve the above benefits.

Council has advised that dredging would be the likely ongoing means of removing sand from the Lake Cathie entrance. A sand slurry could be pumped to outlets along the back of Lake Cathie beach and discharged along the Illaroo Road frontage (approximately 330 m in length), tapering off along the Johnathon Dixon Reserve frontage (a distance of approximately 170 m). A temporary or permanent pipeline could be considered. Sand would then be shaped across the beach to form a ‘natural’ profile, with the area at the back of the beach fenced and planted to stabilise the sand and form a vegetated dune.

5.1.2 Potential Impacts


Modelling by GHD (2004) predicted that removal of sandbanks downstream of the Ocean Drive Bridge to design depths would result in only minor changes, e.g:

� small increase in flow velocities in the vicinity of the Ocean Drive Bridge structures and estuary mouth

� small decrease (<0.05 m/s) in flow velocity within the dredge area, as a result of the increased conveyance (waterway area) in the entrance.

Beach nourishment, using compatible material, provides a ‘natural’ buffer to development that maintains or enhances beach amenity and access. A vegetated dune would form a natural backdrop to the beach and larger beach nourishment volumes would provide a wider beach for recreational activities.

If additional sand was added to the system, this would have implications for entrance management, as some imported material would be transported into the entrance (as currently occurs) under northerly longshore drift. This may mean more frequent dredging is required to maintain depths for recreational activities and the entrance may close more readily, requiring additional mechanical openings to reduce nuisance flooding.

Ecological Impacts

Benthic organisms would be removed along with dredged sand from the Lake Cathie entrance (and other borrow sites if used) and deepening the entrance area would alter habitat for wading bird species. Where sand is placed along the beach benthic organisms may be smothered and buried. However, the beach and entrance area are dynamic environments and undergo significant changes due to natural processes e.g. seasonal erosion and accretion of the beach profile and changes to water depths and currents depending on entrance condition (closed, open and intervening phases). Accordingly,


fauna utilising these environments are either adapted to these conditions or are able to relocate to more suitable habitat.

Stabilising and vegetating nourishment sand would assist in widening the narrow regeneration area along Illaroo Road, forming a contiguous dune system along Lake Cathie Beach which would provide a wildlife corridor and habitat for native fauna.

Social Impacts

As the sand ‘buffer’ would be subject to erosion during storm events and the beach would still be subject to normal seasonal fluctuations, this option may not be perceived by the community as effective. This option may not provide certainty for Illaroo Road property owners as beach nourishment may not be possible when it is required.

5.1.3 Development Controls

As this option relies upon the availability of sufficient volumes of nourishment sand at the time it is needed, the effectiveness of this option as a risk mitigation measure is uncertain. Accordingly, the following additional development controls shown in italics (based on those identified in Section 4.2) could be applied as part of this option. The reference to hazard lines has been deleted as, depending on the nourishment volumes, theoretically the hazard lines could ‘move’.


� Development must be in accordance with the applicable Coastal Zone Management Plan.



� For the purposes of Clause 7.6 (3) (f) of the LEP, the trigger for relocation, modification or removal of development along the Illaroo Road frontage is:








5.2 Revetment

A revetment (or seawall) can be a vertical or sloped structure and is designed to prevent storm erosion and shoreline recession, thereby protecting foreshore development. A typical revetment cross-section is provided in Appendix D. Revetments can be designed to readily facilitate future extension requirements and crest levels can be raised to address future sea level rise. A revetment could be combined with beach nourishment to mitigate the impacts of the structure on the beach.


Revetment

This option would involve construction of a revetment along Illaroo Road, approximately 400 m long. The structure should be placed as far landward as possible so that it remains partially buried and only fully exposed during storm events. Construction should be timed to occur following major storm erosion (e.g. where the shoreline has eroded back to the Illaroo Road carriageway). In the event that the shoreline had eroded back to the property boundaries the revetment could be designed to provide shared pedestrian and local resident vehicle access along the crest. This may involve the seawall being partially located on private property. Alternative public vehicle access to Johnathon Dixon Reserve and the associated carpark is available from Kywong Street and Aquatic Reserve can be accessed from Bundella Avenue.

A sloped rock revetment would be the most appropriate structure at this location. This would aid in reducing stability issues due to erosion in front of the structure as wave reflection is not as significant on a sloped structure, compared to a solid vertical seawall.

The estimated construction cost for the revetment is $2.94 M. More details on concepts and cost breakdowns are provided in Appendix D. Note: should suitable local quarry rock be unavailable at the time of construction, concrete proprietary units may be required. The use of concrete units would be likely to increase costs significantly.

Beach Nourishment

Due to impacts on beach access and amenity (see Section 5.2.2), revetments are often considered in conjunction with periodical beach nourishment. The cost of beach nourishment to maintain beach amenity (assuming a volume of 46,000 m3 to account for future losses due to sediment loss and sea level rise) would be an additional $800,000 initially, with the same cost every 10 years on average.



Whilst revetments perform well in arresting the continued recession of the foreshore and storm erosion, they often exacerbate erosion of the area immediately seaward of the structure and have ‘end effects’ (i.e. increased erosion at the transition between the hard structure and erodible foreshore).

Given the erosive (and receding) environment at Lake Cathie, construction of a revetment is likely to result in the development, over time, of an artificial headland. This would occur as erodible material is removed from in front of, and at the ends of, the revetment. This would also create stability issues and, as recession of the foreshore occurs, the revetment is likely to be outflanked at some point in the future. The outflanking mechanism is likely to require a future extension of the revetment to protect infrastructure to the south, such as the public carpark at Johnathon Dixon Reserve. The Lake Cathie entrance would also


be affected by end effects, accelerating loss of the beach berm. These impacts would be exacerbated by sea level rise.

Public access may be compromised by construction of a revetment and the beach may be lost adjacent to the revetment. If this option was adopted, public access should be provided along the revetment crest (which will ultimately become the foreshore). This could take the form of an elevated boardwalk/ cycleway, or similar arrangement.

If sufficient nourishment sand volumes were available they may assist in addressing loss of the beach in front of the revetment and end effects.

Ecological Impacts

Construction of a revetment would replace the vegetated dune slope and an essentially sandy habitat with a rocky habitat at Illaroo Road. It may also replace an intertidal habitat with a sub-tidal habitat. End effects could result in loss of dune vegetation to the south and scouring of the entrance berm and shoal to the north.

This may encourage the entrance to break out to the south and may result in the entrance being mostly open (rather than intermittently closed and open). This would increase salinity and tidal influences and may affect the life cycles of crustaceans and fish. Loss of the beach and changes to the entrance may also affect shore and wading bird habitats.

Social Impacts

A revetment would protect the foreshore properties at risk and provide certainty to owners. Benefits to the 17 affected property owners would include:

� continued vehicle access to properties

� removal of development constraints associated with coastal hazards

� potentially an increase in property values.

Depending on the revetment location and design, public pedestrian access and vehicle access could be maintained along Illaroo Road. However, a revetment would adversely impact the visual appearance and amenity of the beach.

Recreational use (swimming, surfing and beach fishing etc.) would be impacted due to changes in sand distribution. For example, there may be no beach south of the entrance, which is the current flagged swimming area in summer and the character of the entrance area may change.

Impacts on recreational use may have flow on effects to tourism income. TRA (2009) found that 2008 low and 2007 shoulder season visitors identified beautiful beaches and waterways as one of the top three attributes they expected on their visit to the Greater Port Macquarie area, and the second most popular activity for domestic overnight visitors to the Port Macquarie-Hastings LGA (based on a 3 to 4 year average to 2007) was going to the beach (TRA 2008). If the area became less attractive to visitors, a reduction in visitor numbers would mean a reduction in holiday rental income and spending on meals etc at local businesses.


A revetment, designed and constructed to an appropriate engineering standard, would provide adequate protection for properties along Illaroo Road and so over the 50 year planning period no additional development controls would be required.


5.3 Groyne

A groyne or groyne fields are structures which extend out from the beach and are designed to trap sand to build a wider beach. A groyne could be constructed on the southern side of the Lake Cathie entrance as either a trial structure from geotextile containers, or a permanent rock structure. This option would need to be accompanied by initial beach nourishment as described below.


Based on SMEC’s experience on similar studies for the NSW coast, a groyne would need to extend at least to the – 3 m AHD contour to be effective in trapping sand to provide an adequate buffer to Illaroo Road. This would involve construction of a rock groyne, at least 180 m long, on the southern side of the entrance to Lake Cathie at an estimated cost of $2.23 M, see Appendix D for more details. This would effectively compartmentalise the beach between Middle Rock and the Lake Cathie entrance. As there is limited supply of sediment to this length of coastline, initial nourishment of the beach compartment would be necessary. For assessment purposes it is assumed that long-term recession due to sediment loss via longshore drift is stopped by the groyne. Accordingly, only protection against long-term recession due to sea level rise would be required.

This would mean an initial nourishment volume of say 46,000 m3, to provide an initial buffer to Illaroo Road, prior to sand being trapped behind the groyne, and to account for recession due to sea level rise over 10 years. Maintenance nourishment of approximately 30,000 m3, on average every 10 years, would be required to address sea level rise. The estimated cost of initial beach nourishment is $800,000, with periodical maintenance nourishment around $320,000. These estimates include an allowance for approvals etc as indicated in Appendix D.

If this option was adopted it is recommended that it be preceded by a trial structure to assess the likely effectiveness of a groyne given uncertainties concerning:

� local wave climate (e.g. lack of local/ regional directional offshore wave data and limited understanding of the influence of local features such as the reef associated with Middle Rocks)

� information on sediment budget (volume of sand moving into and out of the Rainbow Beach-Cathie Beach-Lighthouse Beach embayment) etc

� and hence modelling predictions.

As noted above, temporary groynes can be constructed from geotextile fabric containers to assess effectiveness and fine-tune design parameters (length, orientation and location). In an attempt to minimise impacts on Lake Cathie (as a groyne would effectively form a breakwater, thereby training the entrance), the trial groyne could be progressively built out from the shoreline from say 120 m. An additional groyne (e.g. located near the southern end of Illaroo Road to form a short beach compartment) could also be trialled. For each trial configuration, regular monitoring of shoreline changes, north and south of the Lake Cathie entrance, should be undertaken over a period of at least one year.

The estimated cost of a trial groyne approximately 180 m long and 3 m high is $300,000, based on supply and placement of 1125 filled, 2.5 m3 geotextile bags.



Groynes (or groyne fields) are typically constructed on receding shorelines where significant longshore transport in one direction exists. At Lake Cathie, sediment would be


trapped behind the groyne in front of Illaroo Road when sediment transport was to the north but during periods when sediment transport was to the south, sand would be trapped in the Lake Cathie entrance.

The groyne may lead to a change in the open/ closed regime of Lake Cathie entrance and act as a training wall/ breakwater resulting in the lake being mostly open (this has advantages and disadvantages, see discussion on social impacts). Alternatively, altered wave refraction/ diffraction patterns around the head of the groyne adjacent to the lake entrance may result in sediment being “recruited” from the northern side of the entrance to fill the entrance compartment. This would lead to exacerbated recession of the northern foreshore (i.e. greater than the expected downdrift erosion, discussed below).

Due to longshore drift and the eroding nature of the Lake Cathie foreshore (sediment deficit in the compartment), downdrift erosion would occur if the groyne was effective in capturing sand.

A groyne would impact on the visual amenity of the beach and represent an impediment to access. In addition, with scour induced along the groyne and a mostly open entrance, access along the beach at the entrance to Lake Cathie may be difficult.

Ecological Impacts

Erosion of the northern shoreline of Lake Cathie would impact on the mixed forest, woodland and shrubland vegetation community that occurs in this area.

An open entrance allows recruitment of estuarine fish, crabs and prawns into the estuary. When the entrance is closed, fish and shellfish then ‘grow-out’ in the estuary (Umwelt, 2003). Consultation with regular or commercial fishers indicated that fish numbers were largely dependent on seasonal recruitment with fish size likely to be greatest after the entrance had been closed for a year or more (BMT WBM 2011). Accordingly an open or mostly open entrance could impact on commercial and recreational fishing. The lake is already impacted by mechanical opening when the water level reaches 1.6 m AHD and Council records indicate that, on average, the lake opened/ was opened once a year between 1996 and 2009, with an open entrance maintained on average for 5 months (BMT WBM 2011).

An open or mostly open entrance would result in Lake Cathie becoming a more marine system. An open entrance would lead to lower than average water levels (as entrance scouring would hinder building of the berm) and increased tidal influence. BMT WBM (2011) noted that the majority of tidal flows into the estuary are conveyed upstream towards Lake Innes, as the restricted opening beneath the Kenwood Drive Bridge controls tidal flow and substantially reduces the tidal range in Lake Cathie. Hence the originally fresh Lake Innes may be further impacted by oceanic influences. However, widening of the Kenwood Drive Bridge in the future (as noted in the introduction to Section 5) would increase the potential impact on Lake Cathie.

Widening the Kenwood Drive Bridge combined with a groyne structure could result in changes to the distribution of tidal and shallow water vegetation habitats e.g. distribution of saltmarshes and the distribution of terrestrial fauna habitats e.g. water bird foraging, roosting and nesting areas. As noted in Section 1.2.5, saltmarshes and other fringing vegetation communities around Lake Cathie are considered EECs under the TSC Act 1995 and Lake Cathie provides habitat for threatened and migratory water birds.

As noted above, construction of a groyne at the Lake Cathie entrance would effectively be a training wall. DECCW (2010b) identified potential effects of training walls as resulting in the loss of sandy habitats used by shorebirds and loss of subtidal soft-benthic habitats reducing food for bottom-feeding fish, but increasing the populations of invertebrates that


live on hard substrata, therefore providing food for a different type of fish species associated with reef communities.

Social Impacts

If a groyne was effective in containing the movement of sand following initial nourishment, the following benefits may be realised:

� increased beach width for public use and as a buffer for property protection during a storm erosion event

� the need for subsequent nourishment campaigns (and hence anticipated maintenance costs) would be reduced.

Groynes may enhance surfing conditions through altered sand distribution and wave reflection, refraction and diffraction processes and the resultant wave interactions. Opportunities for fishing may also be enhanced by the introduction of a rock structure in the nearshore zone. However, neither of these outcomes can be guaranteed and flow on tourism benefits would be unlikely unless surfing and fishing conditions were significantly improved. Conversely, as a result of the potential ecological impacts associated with an open entrance, commercial and recreational fishing and prawning in the lake may be adversely impacted.

An open entrance may improve water quality for recreational activities (i.e. increased exchange of estuarine waters with ocean waters – it is noted that water in Lake Cathie is sometimes discoloured by tannins), however, safe wading areas for children would be reduced. As noted in Section 1.2.5 the entrance is the most intensively used area of the lake.

A groyne (or groyne field) relies on the modification of coastal processes to maintain a sand buffer to storm erosion. It does not ensure protection for foreshore assets and as such does not provide certainty for property owners. As a result, the potential benefits may not be perceived by the community and foreshore property owners as justifying the cost of this option.


Coastal processes investigations for Lake Cathie have indicated that directionality in sediment transport alongshore can vary under different conditions. This casts uncertainty on the effectiveness of a groyne(s) as a method of retaining beach width and consequently protecting property and assets at risk.

Hence, additional development controls that could apply are the same as for beach nourishment, i.e:


� Development must be in accordance with the applicable Coastal Zone Management Plan.




� For the purposes of Clause 7.6 (3) (f) of the LEP, the trigger for relocation, modification or removal of development along the Illaroo Road frontage is:








6 FUNDING SOURCES

Under the Local Government Act 1993, “Coastal Protection Works” means activities or works to reduce the impact of coastal hazards on land adjacent to tidal waters and includes seawalls, revetments, groynes and beach nourishment. Works may be constructed by, or on behalf, of landowners or by landowners jointly with a council or public authority. Funding assistance and other mechanisms which may be available to Council to assist in the implementation of options and maintenance of coastal protection works are discussed below.

6.1 Funding Assistance

6.1.1 NSW Government Grant Programs

Under the 2012-13 Office of Environment and Heritage (OEH) grant application guidelines, eligible coast and estuary projects include:

� preparing (or updating) coastal zone management plans and associated technical studies (including estuary health and coastal hazard assessments)

� taking actions to manage the risks from coastal hazards

� taking actions to implement environmental repairs, including habitat restoration and conservation projects

� undertaking pre-construction activities for projects that are eligible and are likely to proceed to construction

� developing management tools (e.g. education projects).

It is noted that a higher priority will be given to projects that address public safety risks; protect valuable publicly-owned assets; and/ or protect, maintain or improve high conservation value environments (OEH 2011).

Funding assistance is provided on a 1:1 basis (State Government: Local Government) Property purchase and acquisition are not currently a high priority for funding assistance. In addition, funding assistance for maintenance works is not usually available through grant programs.

6.1.2 Commonwealth Government Grant Programs

The Commonwealth Government funds Coastcare projects undertaken by Local Government, community groups and other not for profit organisations. The funding program is divided into two categories: small projects up to $50,000 and larger scale projects ($250,000 to $450,000). Eligible projects cover marine/ coastal/ estuary/ wetland projects as described below.

� Biodiversity, restoration and rehabilitation projects such as weed control, revegetation/ regeneration of native species, habitat restoration, protection of Aboriginal sites and threatened species and endangered ecological communities.

� Educational/ recreational projects such as information/ interpretive signage, coastal walks and beach accessways as part of foreshore management, and species surveys and environmental monitoring.

Accordingly, the only coastal zone management option component that may be eligible for funding is dune restoration and rehabilitation.


The Commonwealth Government’s Auxiliary Disaster Resilience Grants Scheme (ADRGS) is available to Local Government but targets projects that reduce multiple natural hazards. Funding for structural works appears aimed at ‘disaster proofing’ existing buildings at risk and other engineered works that offer protection from natural disasters.

The ADRGS contributes to the NSW Floodplain Management Program, so that in some circumstances 1:1:1 (Commonwealth: State: Local Government) funding is available. However, there is no equivalent arrangement for the NSW Coastal and Estuary Grants Program.

6.2 Levies

6.2.1 Special Rates

Council could raise funds for acquisition or purchase via a special rate. The amount of special rate is based on Council’s assessment of the relationship between the cost or estimated cost of the work, service, facility or activity and the degree of benefit afforded to the ratepayer by providing or undertaking the work, service, facility or activity.

Special rates are classified as part of Council’s general income. The NSW Independent Pricing and Regulatory Tribunal (IPART) sets the annual rate peg for general income (which was a maximum 2.8% increase for the 2011/ 2012 financial year). Councils can, however, apply to IPART for special variations to increase their general income by more than the rate peg on a permanent or temporary basis. Environmental and infrastructure levies are examples of special rates.

6.2.2 Coastal Protection Services Charge

Under the Local Government Act 1993 “Coastal Protection Services” means to maintain and repair coastal protection works, or to manage the impacts of such works (e.g. changed or increased beach erosion elsewhere), but does not include a service that relates to emergency coastal protection works. Services can relate to private coastal protection works (e.g. a seawall or revetment) wholly on the parcel or on a neighbouring parcel of private land and services outside the council’s area (e.g. below low water mark).

Clause 496B of the Local Government Act 1993 provides for the making and levying of annual charges for coastal protection services for properties that benefit from coastal protection works. The coastal protection services charge is not applicable to property purchase or acquisition, as this would in effect have affected property owners contributing to the government’s cost to purchase or acquire their property.


7 OPTIONS ASSESSMENT

The options assessment takes into consideration the:

� Coastal Management Principles as shown in Figure 3.1.

� Objectives of the Coastal Protection Act 1979.

� Goals, objectives and principles of the NSW Coastal Policy 1997 and the NSW Sea Level Rise Policy Statement 2009.

The principles of Ecologically Sustainable Development (ESD) are embodied in the Coastal Protection Act 1979 and NSW Coastal Policy 1997. The objectives of the NSW Sea Level Rise Policy Statement 2009 are to see coastal communities adapt to rising sea levels in a manner that minimises the resulting social disruption, economic costs and environmental impacts.

A summary of the options assessment is presented in Table 7.1 in terms of:

� financial impact (including the results of a benefit-cost analysis)

� impacts on coastal processes, beach amenity and access

� ecological and social impacts

� the certainty of the option in protecting assets

� confidence in predicting likely impacts associated with each option.

Due to the difficulties in assigning a monetary value to ecological and social costs, comment has been provided on the likely adverse impacts of options. However, a dollar value has been assigned to beach amenity based on a review of research on the ‘value of a beach visit’ and ‘willingness to pay’ to maintain beach amenity (see Section 7.1.2).

A 50 year planning period was adopted for the financial assessment as:

� this would be the likely design life of coastal structures, as noted in Section 5 (periodical beach nourishment would be required to maintain beach amenity over the planning period)

� the 2050 and 2100 hazard lines (see Appendix C) will be periodically revised over the next 50 years based on further data on wave climate and sediment budget etc, further research on climate change induced sea level rise, and the actual shoreline recession experienced at Lake Cathie.

As money is worth more now than it will be in the future, the benefit-cost analysis included calculation of the Net Present Value (NPV) of costs and benefits, using a discount rate of 7%, as per NSW Treasury (2007) guidelines. See Appendix E which provides a summary of the NPV analysis including the financial benefit-cost of options. Section 7.1 provides a discussion on the assumptions made as part of the financial assessment.

7.1 Assumptions

7.1.1 Property Values

As noted in Section 4.3, beachfront land values would be expected to continue to decline over time in light of experienced coastal erosion and recession. Accordingly, the option of purchasing properties over 50 years has been costed on the basis of values declining from estimated current market value to 2009 land value at the end of the 50 year period. Although properties may be able to be rented out to recoup some purchase costs,


managing and maintaining land improvements over the next 50 years involves a cost. This is because the market value for a dwelling in 50 years time would approach land value if it was not maintained, renovated or replaced. The estimated current market value of properties has been used to cost property acquisition and options designed to protect or maintain a buffer to dwellings, assuming these were effective. Values ranging between market value and land value have been adopted (see Table 7.1) for service relocation and where nourishment volumes are not adequate to provide the necessary buffer to Illaroo Road dwellings.

7.1.2 Beach Value

A review of published Australian and international data on the value of a beach visit was presented in WorleyParons (2010). This ranged from around $15 to $100 per visit based on travel cost methods and from about $30 to $70 per annum per person based on ‘willingness to pay’ to maintain beach amenity (e.g. to prevent beach erosion or for beach nourishment).

Most of the data on the value of a beach visit related to high profile tourist destinations, such as the Gold Coast. In determining the value of a beach visit to the Port Macquarie coast, a comparison was made of visitor numbers and trip spend for the Gold Coast and other LGAs north of Sydney, with these expressed as percentages. A corresponding value for a beach visit was determined for each LGA, assuming the Gold Coast had the highest trip spend per visit, per annum ($100) and the LGA with the lowest visitation had the lowest trip spend (i.e. $15). This was considered reasonable as travel costs (e.g. accommodation, food and drink, transport fares, fuel etc.) associated with visiting a beach where visitation is high would be expected to be higher.

Through the method described above, the value of a beach visit to the Port Macquarie coast was estimated at $27 per visit. To convert the value of a beach visit to a value for the beach at Lake Cathie, $27 was multiplied by the estimated number of visitors to the beach per annum (estimated at 10,000 based on records by Council’s surf life savers), giving a value of $270,000 per annum.

7.1.3 Asset Protection Option Costs

Preliminary cost estimates for each engineered management option are provided in Appendix D for the purposes of options assessment. Note that the estimates should be considered as indicative of the relative order of magnitude only. Consistency in costing assumptions has been maintained across the different options such that a comparative assessment is possible.

The preliminary cost estimates are based on general advice from contractors and suppliers on dredging and materials costs, SMEC’s experience and judgement as a firm of practising professional engineers familiar with the construction industry, and with reference to Rawlinsons (2011). Due to the conceptual nature of option designs, actual costs for implementation would be subject to variation. For the purposes of budgeting for implementation of the CZMP, preliminary costs estimates for any preferred option(s) should be refined, based on detailed design.

The value of services at risk, (water mains, power lines, roads etc.) associated with properties at risk has not been costed (apart from the short-term services relocation option) because, although these assets may be lost due to shoreline recession they would no longer be required to service private residences and conversely, if works were undertaken to protect property, services and roads would also be protected.


7.1.4 Benefit-Costs and NPV Analysis

The benefits shown in Table 7.1 for engineered options are based on the assumption that these options would provide asset protection. As discussed in Section 5, and indicated in Table 7.1, there are considerable uncertainties regarding some options. In the case of beach nourishment the ‘assumed’ benefit to affected properties diminishes as nourishment volumes reduce.

As noted in Section 5.2.1, if a revetment was constructed this should occur when the escarpment has eroded back to the Illaroo Road carriageway, so construction could be delayed to some point in the future. However a major beach erosion event (or series of events) could occur at any time and so capital expenditure was included in the NPV analysis in year 1. If construction was delayed to a future date, for the purposes of the NPV analysis, there would have to be an associated reduction in option benefits as the risk to assets increases over time. Also, for consistency, the capital costs of all engineered options were included in year 1. In the case of service relocation, capital costs were included at year 20, as it is possible that services could be maintained in the short-term subject to periodical road maintenance (which was included at year 1 and year 10).

In the case of acquisition there are legislative ‘time limits’ (as noted in Section 4.4.) on the implementation of this option, once a notice has been issued to owners. So for the purposes of the NPV analysis this was assumed to occur in year 1. In the case of voluntary purchase, the NPV analysis was based on the purchase of one property every three years. Market values were assumed to decrease to land value at the end of year 50, as the 2050 hazard line (see Appendix C) implies that the position of the escarpment in the event of a major storm erosion would approach the landward boundary of properties along Illaroo Road (i.e. there would no land left on which to site a dwelling).

The maintenance costs (structures and beach nourishment) have been input to the NPV analysis at the time periods indicted in Section 5 and Table 7.1. Costs and benefits associated with development controls have not been included in the assessment of options as these controls already exist. The possible additional controls essentially provide more guidance for future development.

Benefit-costs and the Benefit-Cost Ratio for all options are shown included in Table 7.1. Benefit-Cost is the NPV of the costs (including maintenance costs and loss of beach amenity) of the option minus the NPV of the benefits of the option over the planning period (in this case 50 years). The disadvantage of this method is that the scale of the project is not taken into account (i.e. magnitude of option costs).

The Benefit-Cost Ratio is the benefit of the option in NPV divided by the capital and maintenance costs of the option in NPV terms over the planning period. If the value of the benefit is greater than the cost, i.e. ratio is one or greater, a project is generally taken to be financially feasible. However, this can be misleading when choosing between more than one option, as it is only a measure of relative benefit.

The Cost-effectiveness Ratio is another benefit-cost method where benefits are measured in physical quantities rather than monetary units (units of benefit over costs). This can be useful in evaluating public sector projects although the units of benefit assigned are subjective (e.g. benefit of option that does not impact on ecological or social values is 10, while an option that has a major impact on ecological or social values might be assigned a value of 2). Due to the subjective nature of this method an overall ranking system for options has not been provided. Instead comment on intangibles has been provided in Table 7.1, along with the consistency of the option (e.g. low, medium, high) with the ecosystem health and community uses principles as outlined in Figure 3.1.


Table 7.1 Summary of Costs, Benefits and Impacts

Option Cost $ Cost

(current) Benefit

$ Benefit

(current)

Benefit-Cost $ (Net Present Value)

Benefit-Cost Ratio

Impacts on coastal processes, beach amenity

and access Ecological impacts Social impacts

Confidence in predicting impacts

Certainty in protecting assets

over 50 year planning period

Consistency with ecosystem health & community uses

principles

1 (a)

Service relocation (at year 20)

move/ rebuild road for one way access (310 m)

relocate water main

relocate power poles (9)

relocate phone cables

access road maintenance

demolition – dwellings plus access

100,000

200,000

90,000

50,000

20,000/10yr

290,000

Total cost over 50 years: $830,000

estimated land value of 17 properties based on 2009 valuation (assumes land value reverts to $0 after 50 years, so benefit taken to be half land value)

3,100,000 2,937,200 19.0

allows for shoreline recession

possible restriction of public access along Illaroo Road

likely loss of public vehicle access

periodical visual impacts due to storm damage

periodical loss of dune vegetation

Illaroo Road residents could enjoy use of properties for a longer period but the timeframe is uncertain

financial impacts associated with declining property values

emotion strain associated with uncertainty and financial impacts

eventual loss of private assets

high

low - does not protect against storm erosion or limit shoreline recession

medium

1 (b)

Property purchase

purchase 1 property every 3 years (assume market value decreases each year to current land value at year 50)

Demolition costs

8,224,000

260,000

Total cost over 50 years: $8.48M

beach amenity 270,000/yr 1,305,700 1.5

does not interfere with coastal processes

potential to improve beach access and foreshore amenity

potential for dune restoration

owners of affected properties could choose when to sell

market values may decline over time

possible financial strain

high

medium - over time removes assets at risk from storm erosion and coastline recession

high

1 (c)

Property acquisition

(at year 1)

acquire 17 properties at current market value

compensation for acquisition

demolition costs

10,500,000

684,000

260,000


beach amenity 270,000/yr -7,723,000 0.3

does not interfere with coastal processes

facilitates improved beach access and foreshore amenity

potential to provide additional foreshore open space

facilitates dune restoration and improvements to wildlife corridors

stress associated with being forced to move

access to compensation for market value of property and other costs associated with moving

high

high - removes assets at risk from storm erosion and coastline recession

high

2 (a)

Beach nourishment to ‘move’ hazard line seaward of Illaroo Road

initial nourishment cost + dune works

ongoing maintenance nourishment + dune works

2,440,000

860,000/10 yr


assumes current market value of 17 properties is maintained

10,500,000 7,201,000 3.2 mimics natural coastal dune buffer system

wider beach for recreational activities

provides potential to improve beach access from Illaroo Road

additional sand would be transported into Lake Cathie entrance which may close more frequently

temporary impacts on biota and habitats when dredging and nourishment occur

facilitates augmentation of vegetated dune system

uncertainty for property owners as protection relies on a sand buffer

may not be perceived as justifying cost as nourishment sand would be redistributed under wave and current action

more frequent entrance closures may affect water quality and inundation risk

moderate – due to impacts on Lake Cathie entrance

medium - does not ensure property protection, relies on availability of suitable sand source when nourishment is required

medium

2 (b)

Beach nourishment to ‘hold’ hazard line in current position

initial nourishment + dune works

ongoing maintenance nourishment + dune works

860,000

860,000/10 yr


assumed value of 17 properties (between current market and 2009 land value as road access etc may be lost at some time during next 50 years)

8,350,000 6,631,000 4.9

does not substantially affect coastal processes

may provide wider beach for recreational activities


potential to augment vegetated dune system

emotional and financial impacts associated with uncertainty in effectiveness of option

access and services to affected properties still at risk

high

medium to low - does not ensure property protection, relies on availability of suitable sand source when nourishment is required

medium - high


Option Cost $ Cost

(current) Benefit

$ Benefit

(current)

Benefit-Cost $ (Net Present Value)

Benefit-Cost Ratio

Impacts on coastal processes, beach amenity

and access Ecological impacts Social impacts

Confidence in predicting impacts

Certainty in protecting assets

over 50 year planning period

Consistency with ecosystem health & community uses

principles

2 (c)

Beach nourishment to mitigate storm impacts

Initial nourishment + dune works

ongoing nourishment + dune works

380,000

380,000/10 yr


2009 land value of 17 properties (road access, services & dwellings are likely to be lost by end of 50 year period)

6,200,000 5,440,400 8.2

Does not affect overall coastal processes


emotional and financial impacts as affected properties become more at risk over time

high

low - does not provide property protection over the 50 year planning period

high

3 (a)

Revetment

capital cost

maintenance cost (assume 3.5% of capital cost)

loss of beach amenity

2,942,000

103,000/5yr

270,000/yr

Total cost over 50 years: $17.47M (including cost of loss of beach amenity)


10,500,000 3,584,600 1.5 visual impact of exposed revetment

increased recession at either end of structure resulting in risk to assets at Johnathon Dixon Reserve and accelerated loss of entrance berm

may result in entrance being mostly open

eventual loss of beach in front of revetment

revetment will become an artificial headland as shoreline recedes

replaces a natural sandy habitat with an artificial rocky habitat

loss of dune vegetation to south

changes to habitats and biota as a result of entrance being mostly open

market value of affected properties may be maintained

coastal hazard constraints to redevelop of affected properties removed

potential to maintain existing public vehicle access along Illaroo Road

adverse impact on recreational uses due to loss of beach and end effects which may have flow on impacts on tourism

high

high - provides protection from storm erosion and limits coastline recession

low

3 (b)

Revetment + beach nourishment to account for recession due to sediment loss & sea level rise

capital cost

initial nourishment

maintenance cost (see above)

ongoing beach nourishment

2,942,000

800,000

103,000/5yr

800,000/10yr



10,500,000 5,711,700 2.2 potential loss of public access along Illaroo Road

periodic exposure of revetment and associated visual impact and reduced beach width

possible impacts on Lake Cathie entrance

relies on maintenance nourishment to mitigate loss of beach and end effects

replaces a natural sandy habitat with an artificial rocky habitat but impacts reduced if structure can be buried/ partially buried

market value of affected properties may be maintained

coastal hazard constraints to redevelop of affected properties removed

potential to maintain existing public vehicle access along Illaroo Road

possible adverse impacts on recreational uses

moderate – due to effectiveness of beach nourishment in addressing adverse impacts

high - provides protection from storm erosion and limits coastline recession

low - medium

4

Groyne + beach nourishment to account for recession due to sea level rise

trial costs (not including monitoring)

capital cost

initial nourishment

maintenance cost (3.5% of capital cost)

ongoing beach nourishment

300,000

2,277,000

800,000

80,000/5yr

320,000/10yr



10,500,000 6,611,400 2.7

compartmentalisation of beach

possible exacerbation of storm erosion (offshore losses)

may result in erosion on the southern side of the entrance

loss of sand in front of Illaroo Road when local sediment transport is to the south

visual impact

impediment to access along the beach

significantly altered beach state and surf character

entrance likely to be mostly open

replaces a natural sandy habitat with an artificial rocky habitat

potential to change local species composition

redistribution of flora and fauna habitats, impacts on aquatic biota life cycles due to entrance being mostly open

possible improved water quality

possible impact on market value and emotional stress associated with uncertainty in option effectiveness

possible increased beach width for recreation in some circumstances

may provide surfing and beach fishing benefits

ecological impacts could adversely affect prawning and commercial and recreational fishing in the lake

possible water quality benefits due to an open entrance

safe wading areas in the entrance would be reduced

visual impact

low – introduces artificial structure in active beach zone, complexity of coastal processes makes impact assessment difficult

medium to low - does not ensure property protection, relies on sand buffer

low - medium


7.2 Funding Scenarios

The Guidelines (DECCW 2010a) require funding arrangements to be included in CZMPs and that the priority for public expenditure is public benefit, as per the Coastal Management Principles, see Figure 3.1.

If no action was taken to address coastal hazards affecting Illaroo Road and associated properties overtime beach amenity, the narrow dune and access along the road would be degraded and eventually lost. Therefore beach nourishment and options including beach nourishment provide some public benefit over the 50 year planning period, as well as service relocation which aims to prolong public access along Illaroo Road.

Accordingly, the public benefit assigned in Table 7.2 relates to maintaining or enhancing the coastal environment and maintaining or enhancing public access and recreational benefit. The assigned private benefit relates to the certainty of the coastal protection work in protecting private assets.

Table 7.2 Assigned Private – Public Sector Contribution Percentage

Option Certainty in protecting

private assets

Assigned private benefit

Consistency with coastal ecosystem health & community

uses principles

Assigned public benefit

1 (a) Service relocation low 25% medium - high 75%

1 (b) Property Purchase n/a n/a high 100%

1 (c) Property Acquisition n/a n/a high 100%

2 (a) Beach nourishment to ‘move’ hazard line

medium 50% medium 50%

2 (b) Beach nourishment to ‘hold’ hazard line

low - medium 25% medium - high 75%

2 (c) Beach nourishment to mitigate storm impacts

low - high 100%

3 (a) Revetment* high 100% low -

3 (b) Revetment + beach nourishment

high 75% low - medium 25%

4 Groyne + beach nourishment**

low - medium 75% low - medium 25%

Notes:

*As noted in the Draft guidelines for assessing the impacts of seawalls (DECCW 2010b), a revetment could be voluntarily constructed by a group of landowners (subject to approval) on private property. However, if a revetment was located and designed such that public vehicle and/ or pedestrian access was maintained along Illaroo Road, some public benefit would result and hence private/ public cost-sharing could be negotiated.

**Although the groyne and nourishment option would be anticipated as having a low to medium certainty in protecting private assets, it would be likely to have a relatively high impact on ecological and beach amenity values, with only the nourishment component having any public benefit, hence the private benefit has been assigned as 75%.


Table 7.3 shows an example of the breakdown of capital costs to Illaroo Road property owners and under different public funding sector scenarios. Note that the cost under shared public sector funding is the individual contribution for each public authority.

As noted in Section 7.1.3, these breakdowns are based on preliminary cost estimates for the purposes of options assessment and should be considered as indicative of the relative order of magnitude only. Should an engineered option be adopted in the CZMP, cost sharing arrangements would need to be negotiated between Council and affected land owners based on cost estimates at the detailed design phase, or following the tender process when actual costs are known.

Table 7.3 Example of Private – Public Sector Contributions to Option Capital Costs

Option

Private Contribution

$

Contribution by each Public Authority*

$

Council only contribution

Council & State Government

Council, State & Commonwealth

1 (a) Service relocation 182,500 547,500 273,750 182,500

1 (b) Property Purchase - 8,523,000 4,261,500 2,841,000

1 (c) Property Acquisition - 11,444,000 5,722,000 3,814,670

2 (a) Beach nourishment to ‘move’ hazard line

1,220,000 1,220,000 610,000 406,670

2 (b) Beach nourishment to ‘hold’ hazard line

215,000 650,000 325,000 216,670

2 (c) Beach nourishment to mitigate storm impacts

- 380,000 190,000 126,670

3 (a) Revetment 2,942,000 - - -

3 (b) Revetment + beach nourishment

2,806,500 935,500 467,750 311,830

4 Groyne + beach nourishment

2,532,750 844,250 422,130 281,420

*where funding is shared an equal contribution is assumed, e.g. 1:1:1 Council: State: Commonwealth.

Table 7.4 shows an example of annual maintenance costs to Illaroo Road property owners (or the Coastal Protection Service Charge) and Council. Other public sector funding has not been included as current grant programs do not usually cover maintenance works (see Section 6.1).

The costs in Table 7.4 are the total preliminary maintenance cost estimates, divided by 50 (the planning period) and are indicative only. Note that Coastal Protection Service Charge Guidelines (DECCW 2010c) provide further guidance on cost-sharing and include a number of items to be considered in calculating the charge including legal costs, insurance, accounting and reporting. These potential additional costs have not been included in Table 7.4. Maintenance costs for service relocation have been allocated to Council as these relate to maintenance of the existing roadway.


Table 7.4 Example of Private – Council Annual Contributions to Maintenance Costs

Option Private Contribution

$

Council Contribution

$

1 (a) Service relocation - 2,000

2 (a) Beach nourishment to ‘move’ hazard line 43,000 43,000

2 (b) Beach nourishment to ‘hold’ hazard line 21,500 64,500

2 (c) Beach nourishment to mitigate storm impacts 38,000

3 (a) Revetment 20,600 -

3 (b) Revetment + beach nourishment 75,450 25,150

4 Groyne + beach nourishment 36,000 12,000


8 CONCLUSIONS

8.1 Effectiveness of Options in relation to Risk Management

8.1.1 Planned Retreat

Relocation of services can only be considered an interim option to permit owners/ residents of existing dwellings to continue to enjoy their properties for a longer period of time.

Council has already adopted LEP provisions (which are consistent with the Standard Instrument—Principal Local Environmental Plan) and development controls which will, over the long-term, ensure that development is located landward of areas at risk from coastal hazards. However, development controls do not address the risk to existing properties.

Property purchase or acquisition would remove assets from risk. However, acquisition involves substantial upfront costs (estimated at $10.5 M). Voluntary purchase would enable Council to plan to purchase properties over a period of time. However, rather than owners approaching Council to purchase their property, it is likely that Council would be competing with other purchasers on the open market, as owners seek to maximise sale price. In addition, the necessary funds may not be available when properties come onto the market.

8.1.2 Beach Nourishment

Factors affecting the effectiveness of beach nourishment in mitigating impacts include the following:

� Beach nourishment using only material removed from the Lake Cathie entrance (seaward of the bridge) does not introduce an additional volume of sand, as this sand is part of the active beach system. As noted by (WMA, 1994a), closure of the lake is preceded by the build-up of marine sand in the entrance which progressively restricts tidal flow. The berm then progressively builds under wave action. Accordingly, nourishment using only sand from Lake Cathie entrance would not mitigate shoreline recession due to net sediment loss and sea level rise.

� The estimated volume of sand available from Lake Cathie entrance would not be sufficient to prevent impacts on Illaroo Road in the event of major storm erosion.

� At times the estimated volume of sand may not be available from Lake Cathie entrance. For example PMHC records between May 1996 and October 2009 indicated that on average the entrance opened (was mechanically opened) about once every year with an open entrance maintained, on average, for approximately 5 months (BMT WBM 2011). WMA (1994b) estimated that the average volume of sand scoured from the entrance during a breakout was approximately 18,000 m3. Anecdotal evidence indicates that, following the 1978 flood event, an open entrance was maintained for 2 years (GHD 2004), which suggests that more than 18,000 m3

of material was scoured from the entrance (the beach berm may also have been higher than the current opening trigger level of 1.6 m AHD - a higher water level at which the entrance is breached influences the period over which it remains open).

� The cost of importing nourishment sand to mitigate storm erosion impacts and recession due to net sediment loss and sea level rise over the 50 year planning period is likely to be cost prohibitive and could result in adverse impacts on coastal/ estuarine processes at the borrow site(s).


� If the beach was in an eroded state and nourishment was not possible prior to a major storm event, foreshore assets would still be at risk.

� The longevity of beach nourishment is dependent on weather conditions with unconsolidated sediments being transported offshore and alongshore by waves and currents.

� Adopting beach nourishment as a coastal zone management strategy requires an ongoing commitment to maintenance nourishment.

8.1.3 Revetment

Of the engineered options considered, only the construction of a properly designed revetment provides certifiable protection from erosion events. Beach nourishment and groyne(s) rely in some way on modifying coastal processes such that the risk is reduced.

8.1.4 Groyne

Factors affecting the effectiveness of a groyne(s) in mitigating impacts include the following:

� Offshore transport of sediment still occurs during storm events which would lead to losses from the compartmentalised Lake Cathie Beach and continued recession.

� The groyne may exacerbate the development of rip currents during storm events causing more sand to be transported in the offshore direction thereby increasing recession rates.

� Due to the fluctuations in sediment transport directions along Lake Cathie Beach, the shoreline position within the beach compartment could fluctuate significantly.

� During periods of localised southerly transport, which can occur under certain conditions, sand could be eroded from the southern side of the groyne exacerbating any short-term erosion along Illaroo Road due to storm events.

8.2 Approvals and Public Funding Considerations

With regard to coastal protection works, the following generic disadvantages need to be considered:

� relatively high capital costs (in the vicinity of $2 to $3 M)

� ongoing maintenance costs (in the vicinity of $1 M for structures and $4 M for maintenance nourishment over the 50 year planning period)

� inconsistencies with coastal management Principle 1 including the NSW Coastal Policy 1997 which has as its central focus the ecologically sustainable development (ESD) of the NSW coastline (e.g. ecological impacts and impacts on beach amenity and access).

Any coastal protection works adopted in a CZMP would be subject to the normal environmental assessment and approvals process under the Environmental Planning and Assessment (EP&A) Act 1979 and other relevant legislation. Under Section 55M (1) of the Coastal Protection Act 1979, consent must not be granted under the EP&A Act to development for the purpose of coastal protection works, unless the consent authority is satisfied that:

(a) the works will not over the life of the works:

(i) unreasonably limit or be likely to unreasonably limit public access to or the use of a beach or headland, or


(ii) pose or be likely to pose a threat to public safety, and

(b) satisfactory arrangements have been made (by conditions imposed on the consent) for the following for the life of the works:

(i) the restoration of a beach, or land adjacent to the beach, if any increased erosion of the beach or adjacent land is caused by the presence of the works,

(ii) the maintenance of the works.

Principle 5 of the Guidelines for Preparing Coastal Zone Management Plans (DECCW 2010a) states that the priority for public expenditure is public benefit. A number of funding scenarios were presented in Section 7.2, which included various contributions by Illaroo Road property owners and public sector contributions, base on this principle.

The Guidelines also note that the scale of the management options proposed in a CZMP should be consistent with the amount of funding reasonably likely to be available over the CZMP implementation period and a council’s intended response can be:

� Coastal protection works are considered technically feasible and cost-effective – funding is being sought for implementation

� Coastal protection works are considered technically feasible but not cost-effective for public funding – unlikely to be implemented by a public authority

� Coastal protection works are not considered technically feasible – no intended public authority works.

Property acquisition and voluntary purchase are ‘technically’ feasible options which remove the risk to coastal assets over the 50 year planning period, and may be cost-effective for public funding. It is understood Council would support the purchase of properties if funding was available.

A revetment is a technically feasible option for removing the risk of coastal hazards to private property along Illaroo Road over the 50 year planning period. However, it may not be considered cost-effective for public funding due to adverse impacts and limited public benefit. If a revetment was combined with beach nourishment, sufficient volumes of nourishment material are unlikely to be available to mitigate adverse end effects and adverse impacts on beach amenity.

Groyne(s) and beach nourishment are not technically feasible options as they do not provide certainty in removing the risk to private property along Illaroo Road. In addition, sufficient volumes of beach nourishment material are unlikely to be available to implement these options and, in the case of groynes, this option has the potential to increase the risk to properties under certain conditions.


9 RECOMMENDATIONS

9.1 Risk Management Strategy

Based on the information investigated, assessed and reported in this document, voluntary purchase is the recommended risk management option, pending further detailed investigations into funding options and funding availability.

In determining a preferred risk management option to be included in the CZMP, Council will need to take into account a number of factors including:

� Community feedback following public exhibition of this Stage 2 Management Study

� Council’s current, projected and future financial position

� Council’s current and future negotiations with other government agencies regarding funding for implementation

� Other Council projects which compete for funding allocation

� Council’s current and future legal advice regarding the suitability and enforcement of particular management options

� Future legislative changes which may influence the relative merit of management options (e.g. change to permit the use of offshore marine sands for foreshore nourishment purposes).

These factors should also be considered by Council during subsequent, future reviews of the CZMP.

9.2 General Coastal Zone Management

Based on the outcomes of this study, it is recommended that the following actions be included in the CZMP:

1. Council’s Dredging Strategy (PMHC 2007) be amended to show the preferred spoil disposal location as along the Illaroo Road frontage.

2. Council consider additional DCP provisions based on the hazard mapping, which takes into account the NSW Sea Level Rise Policy Statement 2009.

3. A Servicing Strategy be developed in consultation with other service providers in the event that access and services to Illaroo Road properties are threatened by coastal erosion, prior to the implementation of any long-term risk management options.

4. Ongoing monitoring of the shoreline be undertaken to assess the effectiveness of the existing coffee rock in arresting erosion as a result of ocean storm events (and hence to confirm the storm ‘bite’); and to assist in estimating the actual (as opposed to predicted) extent of shoreline recession.

5. The Coastal Hazard Study be updated as more data becomes available e.g: directional wave data from the waverider buoy at Coffs Harbour (which would be representative of the directional wave climate along the NSW mid-north coast), future photogrammetry, additional bathymetry and updates on climate change induced sea level rise.


It is also recommended that the following actions identified in the Stage 1 Management Study (SMEC 2009) be included in the CZMP:

6. Council continue to upgrade the stormwater outlets to the beach e.g: placement of rock at outlets to reduce beach scour and construction of infiltration zones to reduce the volume of stormwater discharged at beach outlets.

7. Any sand dredged/ excavated from the Lake Cathie entrance be placed on the beach adjacent to Illaroo Road

8. Control/ removal of bitou bush continue along with regeneration/ revegetation with locally indigenous vegetation species

9. Regeneration areas be fenced off to prevent trampling and hence assist in vegetation establishment

10. Educational signage be installed on the importance of dune vegetation in stabilising the dune system which provides a buffer to storm erosion

11. Any storm erosion escarpment that forms at Foreshore Reserve be battered back to ensure public safety and maintain park amenity.

12. Additional lighting be installed at Johnathon Dixon Reserve and in the vicinity of the Foreshore Reserve barbeque facilities

13. Johnathon Dixon Reserve be upgraded to relieve pressure on Foreshore Reserve by incorporating shade, shelter and play areas

14. Aqua Crescent/ Bundella Avenue and Illaroo be designated as a one-way loop to provide safer pedestrian access along Illaroo Road – this would also facilitate narrowing of the road pavement following damage to the road reserve as a result of erosion events (consistent with the interim “relocate services” option).


10 REFERENCES AND BIBLIOGRAPHY

AECOM (2010), Beach Sand Nourishment Scoping Study Maintaining Sydney’s Beach Amenity Against Climate Change Sea Level Rise. Prepared for Sydney Coastal Councils Group.

Berrigan J and Bray D (2002), Flora and Fauna survey of Middle Rock littoral rainforest Lake.

BMT WBM (2011), Lake Cathie/ Lake Innes Estuary Hydrodynamic Model Development and Investigation.

Department of Environment, Climate Change and Water (DECCW 2010a) Guidelines for Preparing Coastal Zone Management Plans.

DECCW (2010b) Draft guidelines for assessing the impacts of seawalls.

DECCW (2010c), Coastal Protection Service Charge Guideline.

Department of Local Government (DLG) 2006, Guidelines for the Compulsory Acquisition of Land by Councils.

Department of Planning (DoP 2010), NSW Coastal Planning Guideline: Adapting to Sea Level Rise.

Department of Primary Industries (DPI 2008), Coastal Quaternary Geology – North and South Coast of New South Wales. Bulletin No.34 A.L. Troedson and T.R. Hashimoto.

DPI (2006), Hastings River recreational fishing guide. Primefact 233, October 2006.

Geomarine and Coffey Partners (1991), Narrabeen-Collaroy Fishermans Beach, Criteria for the Siting and Design of Foundations for Residential Development. Prepared for Warringah Council.

GHD (2004) Maintenance Dredging of Lake Cathie Review of Environmental Factors.

id Consulting (2011), www.hastings.nsw.gov.au Population and Household Forecasts.

id Consulting (2008), Port Macquarie-Hastings Council Community Profile 2006 and 2001 Enumerated Census information for: Lake Cathie – Bonny Hills.

NSW Government (2005), Floodplain Development Manual.

NSW National Parks and Wildlife Service (NPWS 1999), Lake Innes Nature Reserve Plan of Management.

NSW Public Works Department (PWD 1992), Estuary Inventory of New South Wales.

NSW PWD (1991) Lighthouse Beach (north) Photogrammetric Analysis, Contract 89023, February 1991.

NSW Public Works (1990) Bonny Hills – Lake Cathie Photogrammetric Analyses, Contract 89022, May 1990.

NSW Treasury Office of Financial Management (2007), NSW Government Guidelines for Economic Appraisal - Policy & Guidelines Paper tpp 07-5.


Office of Environment and Heritage (OEH) 2011, Coastal and Estuary Management Programs Grant Application Guidelines 2012−13.

Port Macquarie-Hastings Council (PMHC 2011), Snapshots – A publication of Economic Development in the Greater Port Macquarie Region. Edition 19, June 2011.

Rawlinsons (2011), Australian Construction Handbook, Edition 29.

Short (2007), Beaches of the New South Wales Coast, a guide to their nature, characteristics, surf and safety. 2nd Edition. Published by Coastal Studies Unit, University of Sydney and Surf Life Saving Australia.

Tourism Research Australia (TRA 2009) Greater Port Macquarie Visitor Profile and Satisfaction Report: Summary of Results.

TRA (2008) Tourism Profiles for Local Government Areas in Regional Australia New South Wales, Port Macquarie-Hastings Shire.

Umwelt (2004) A Tale of Two Lakes, Managing lake Innes and Lake Cathie for Improved Ecological and Community Outcomes, Issues and Options.

WMA (1998) Lake Cathie/ Lake Innes Waterway Users Study.

WMA (1995) Lake Cathie/ Lake Innes Entrance Opening Strategy Environmental Review.

WMA (1994a) Lake Cathie/ Lake Innes Estuary Management Plan.

WMA (1994b) Cathie Creek Maintenance Dredging Environmental Review.

WorleyParsons (2011), Draft Greater Taree Coastal Zone Management Plan.

WorleyParsons (2010), Greater Taree Coastline Management Study.

Lake Cathieerosionatcathie.yolasite.com/resources/Lake Cathie... · 2012. 9. 8. · Project Name:...

Documents

Transcript of Lake Cathieerosionatcathie.yolasite.com/resources/Lake Cathie... · 2012. 9. 8. · Project Name:...