DRAFT
ESTUARY
MANAGEMENT
PLAN
For
Wallagoot Lake
And Bournda
Lagoon
Prepared By:
Bournda Environmental
Education Centre (BEEC)
And Sulisit Consulting
Contributors:
Members of Wallagoot Landcare
DOCUMENT SUMMARY
Major Funding Body:
Caring For Our Coasts
Via –Southern Rivers Catchment Management Authority (SRCMA)
Funded Project:
The Two gems project
Local Government Area: Bega Valley Shire Council, Australia
Catchment Management Area: Southern Rivers CMA
Prepared By:
Bournda EEC - Doug Reckord and Luke Brown (Project Officer)
Co-Authors:
Sulisit Consulting, 24 Connells Close, Mossy Point, NSW, 2537
Contributors:
Jan Lynch, Bournda Environmental Education Centre
Members of Wallagoot Landcare
ACKNOWLEDGEMENTS
Students and teachers who supported project activities.
Community members who participated in meetings, water quality testing and other events
The Traditional Owners are acknowledged, in particular, members of the Local Aboriginal Community.
Southern Rivers CMA – Kirsti Sampson, Helen Davies and Don McPhee
Bega Valley Shire Council – Derek Van Bracht
Mr Rob High – for permission to access his lands in the Wallagoot catchment
Grant Brewer – Ranger – Bournda National Park
Illustration on front page: Bega High School student investigating biodiversity during the Landcare
camp
Contents
Contents.................................................................................................................................................................................................. 0
List of Figures ......................................................................................................................................................................................... 1
List of Plates ........................................................................................................................................................................................... 2
Draft Estuary Management Plan for Wallagoot Lake and Bournda Lagoon ........................................................................................... 1
Executive Summary ................................................................................................................................................................................ 1
1.
2.
3.
4.
5.
6.
Introduction.................................................................................................................................................................................... 4
1.1.
Importance of Study Area .................................................................................................................................... 6
1.2.
Location of Study Area ........................................................................................................................................ 6
1.3
Community Uses of the Catchments ................................................................................................................... 7
1.4
Cultural Values .................................................................................................................................................... 8
1.5
Identification of Key Stakeholders ....................................................................................................................... 8
1.6
Community and Stakeholder Consultation ........................................................................................................ 10
Estuary Health ............................................................................................................................................................................. 11
2.1
Physical characteristics ..................................................................................................................................... 11
2.2
Estuary Biodiversity ........................................................................................................................................... 13
2.2
Threatened Species .......................................................................................................................................... 17
Ecosystem Health and Stressors ................................................................................................................................................ 17
3.1
Estuary Health Pressures and Stressors ........................................................................................................... 17
3.2
Coastal Risks – Climate Change - Overview ..................................................................................................... 20
Ecosystem Health Assessment and Plans .................................................................................................................................. 22
4.1
Estuary Health Assessment............................................................................................................................... 22
4.2
Ecosystem Health Experimental Design............................................................................................................ 22
Ecosystem Health and Water Quality Status .............................................................................................................................. 23
5.1
Data collected .................................................................................................................................................... 23
5.2
Estuary Health Status ........................................................................................................................................ 24
5.3
Data management ............................................................................................................................................. 25
5.4
Estuary seagrass and habitat monitoring .......................................................................................................... 27
Conclusions (including potential management actions) .............................................................................................................. 28
APPENDIX A ........................................................................................................................................................................................ 31
APPENDIX B ........................................................................................................................................................................................ 33
References............................................................................................................................................................................................ 36
Two Gems Draft Catchment Management Plan
 Sulisit Consulting 2012
List of Tables
Table 1 Land-use comparison................................................................................................................................. 7
Table 2: Management stakeholders identified ........................................................................................................ 9
Table 3: Estuary Characteristics of Wallagoot and Bournda ................................................................................. 12
Table 4 Species diversity and abundance in Wallagoot, compiled by Luke Brown (Bournda EEC)...................... 16
Table 5 Recovery Plans Relevant to Wallagoot Lake ........................................................................................... 17
Table 6 Table Classification of Coastal Lakes – Summary of Data. Independent public inquiry into Coastal Lakes
– Final Report 2002............................................................................................................................................... 18
Table 7 Multiple Scale Estuary Health .................................................................................................................. 19
Table 8 Bournda-Wallagoot Waterwatch Group/Wallagoot Landcare ................................................................... 27
Table 9 Threatened Species List – Bournda Lagoon/Wallagoot Lake Catchments .............................................. 31
Table 10 Comparison of Attributes of the Wallagoot Lake/Bournda Lagoon Catchments .................................... 33
List of Figures
Figure 1 Location map - Wallagoot catchment - red; Bournda Lagoon catchment - mustard ................................. 6
Figure 2 Wallagoot Lake - Caulerpa zone............................................................................................................... 7
Figure 3 Aquatic vegetation communities in Wallagoot Lake, 2009. ..................................................................... 14
Figure 4 Trend in Annual Total Rainfall 1970-2011 – Bureau of Meteorology ...................................................... 20
Figure 5 Trend in Mean Temperature 1970-2011 – Bureau of Meteorology ......................................................... 20
Figure 6 Wallagoot Lake – Coastal Risk mapping based on BVSC 2010 LEP mapping –See GIS Folder 3 ........ 21
Figure 7 Bournda Lagoon Coastal Risk Mapping – BVSC 2010 – See GIS – Folder 3 ........................................ 21
Figure 8 Salinity, expressed as electrical conductivity – units are micro Siemens per centimetre. ....................... 23
Figure 9 Dissolved Oxygen Levels, Wallagoot Lake, Jan 2011-May 2012 ........................................................... 24
Figure 10 Adaptive Management Model (Resilience Alliance and Santa Fe Institute, 2004): ............................... 26
Two Gems Draft Catchment Action Plan
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List of Plates
Plate 1 Bournda Road after heavy rain ................................................................................................................... 2
Plate 2 Bournda Lagoon in flood, entrance closed 29 Jan 2009 ............................................................................. 3
Plate 3 Screenshot from GIS showing drainage network and Wallagoot catchment boundary. ............................. 5
Plate 4 Panoramic view of the open Wallagoot Lake, March 2012. Photo by: Tony Hastings WLBC ..................... 8
Plate 5 Quadrat/Transect study of seagrass – Zostera spp. ................................................................................. 11
Plate 6 Bournda Lagoon – Sept 2007, Note algal blooms. ................................................................................... 13
Plate 7 Wallagoot Lake – Entrance – in open condition, 13th June 2012 ............................................................. 15
Plate 8 4Feb 2010 Flood event – turbid water in Moncks Creek ........................................................................... 18
Plate 9 Wallagoot Lake during the drought, with seagrass beds exposed (January, 2009, Bournda EEC) .......... 27
Plate 10 The future of Landcare - Participants -Two Gems Landcare Camp 2011 ............................................... 35
Plate 1 Bournda Road after heavy rain
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Management Plan
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Draft Estuary Management Plan for Wallagoot Lake and
Bournda Lagoon
Executive Summary
The “Two Gems”, Wallagoot Lake and Bournda Lagoon, are intermittently closing and opening
estuarine lakes or lagoons (ICOLL) located between Tathra and Merimbula, in the Bega Valley Shire.

Water quality monitoring indicates that surface water quality in both estuaries is good.

The Rapid Catchment Assessment has identified priority sites where riparian vegetation has
been damaged, removed or is in poor condition. There are areas where stock access
tributaries of the estuaries.

Both main tributaries (Moncks Creek and Sandy Beach Creek) have large sediment slugs
which require management to protect the estuaries. Expert assessment of these sites is
recommended.

Landholders, whose properties are included in the Rapid Catchment Assessment process, are
willing to discuss on-ground rehabilitation works but have made no commitments beyond that.
There is excellent potential for erosion control, revegetation and fencing works to improve the
catchment condition. Both estuaries are listed as medium priority for estuary management
works by SRCMA.

In Wallagoot Lake seagrass species are recolonising areas exposed by drought conditions in
2006-2010

No Caulerpa was found during the monitoring period and no control measures were required.

Community input to the draft catchment management plan indicates a high level of support for
catchment management that protects the natural values and water quality of both estuaries.

A community geographic information system, or GIS, has been established using Google Earth
and captures a range of information useful to the management of these catchments. The GIS
should be considered as a set of electronic appendices to this document and contains a rich
set of data about the study area.

The catchments contain a stunning diversity of flora and fauna, including many threatened and
vulnerable species.

The catchments have formally identified as suitable for significant (Wallagoot) and
comprehensive protection.(Bournda) (NSW HRC, 2002)

Both estuaries need protection from eutrophication, sedimentation and habitat disturbance and
there are concerns that excessive and/or poorly managed development will compromise the
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Page |2
high conservation status of both estuaries. Bournda Lagoon is particularly vulnerable due to its
small water volume.

Land clearing and construction of roads and batters on erodible soils are leading to land
degradation processes that put these estuaries at risk.

There is intense interest in the management of these estuaries from a wide range of user and
interest groups

While this combined Draft Estuary Management Plan provides important information on estuary
processes and community input, there is a need to provide resources for a more
comprehensive estuary management process.
Key recommendations include:

Bournda EEC and Wallagoot Landcare host a workshop with the BVSC Coastal Planning and
Management Committee to discuss the project’s findings and scope work towards completing a
comprehensive Estuary Management Process for each estuary.

Bournda EEC, NPWS, Southern Rivers CMA and other relevant stakeholders, including the
Aboriginal community, work through the BVSC CPMC to develop separate Draft Estuary
Management Plans for Wallagoot Lake and Bournda Lagoon

Begin negotiations with willing landholders for rehabilitation of riparian vegetation, control of
erosion and management of sediment plugs.
Form an Estuary Management Committee for each catchment:

Under the auspices of the BVSC Coastal Planning and Management Committee with Aboriginal
community membership.
Assemble Existing Data and:



Identify additional resources and more comprehensively collate existing studies and information
on baseline estuary processes, including input from community members.
Collate key research data on water quality and biodiversity into individual catchment
databases.
Conduct an audit to determine if the BVSC Comprehensive Local Environment Plan is
consistent with the coastal lakes sustainability assessments, in accordance with Dept. of
Planning guidelines
Carry Out an Estuary Process Study and:

Provide resources to assemble the baseline estuary process data from existing sources.

Provide support for ongoing water quality monitoring in both catchments.
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Carry Out an Estuary Management Study and:

Further investigate suitable management of erosion prone landscapes including soil erosion
risk mapping.
Plate 2 Bournda Lagoon in flood, entrance closed 29 Jan 2009
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1.
Introduction
This draft estuary management plan will:




provide a brief outline of information about Wallagoot Lake and Bournda Lagoon,
identify key issues and pressures in both catchments and
provide recommendations for catchment action, future monitoring and estuary health
assessment.
Illustrate key information using a Community GIS developed with Google Earth.
The Community GIS developed for this project can be considered as a set of electronic appendices to
this document. The purpose of the resource is to make information about the catchment readily
available to community members. . The GIS contains the following folders:

Folder -1 Catchment Tours – these simulated catchment “fly-overs” give information about the
location of the study area and some basic catchment characteristics.

Folder -2 Rapid Catchment Assessment - A Rapid Catchment Assessment (RCA) was
conducted in both catchments using the “Matrix Criteria for Determining River Rehabilitation
Priorities” SRCMA Coastal Catchments, Version 5. The data for the RCA can be accessed by
downloading a spreadsheet from using the link within the GIS

Folder 3 - Estuary Health - Water Quality Data collected from the project can be downloaded in
spreadsheet form from within this folder. Some additional information on water quality during
the major rainfall event of March 8th 2012 is shown for both catchments.

Coastal risk mapping - Climate change - The BVSC Comprehensive Local
Environment Plan contains coastal risk planning maps based on projections for
sea-level rise. These maps are provided for illustrative purposes only and
should not be relied on for any other purpose. Any person wishing to find
further information about this mapping should contact Bega Valley Shire
Council.
Folder 4 - Natural Environment - A range of information useful for understanding the natural
resources of the catchments is available in this folder including:





Catchment Boundaries mapping - Drawn using the “path” tool in Google Earth
Streams – utilising data supplied under licence to Bournda EEC by the Office
of Environment and Heritage for educational purposes.
Vegetation – computer predictions of extant vegetation. An exciting feature of
the mapping is a photographic resource on vegetation types being prepared by
a community volunteer, Steve Burrows. Clicking on vegetation types will link to
the Bournda Digital Herbarium to aid in an understanding of the major species
within each unit. This component is still being prepared but will help educate
the community about threatened species and endangered ecological
communities within the catchment areas.
Soils – Soil mapping using a digital overlay of mapping by DLWC(Tulau, 1997).
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
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Geology

Folder 5 - Aerial Photographs - Map overlays of older aerial photographs give an indication of
changes within the catchments. Most of the aerial photographs focus on Wallagoot Lake and
there is one image that covers the eastern portion of the Bournda Lagoon catchment.

Folder 6 - Administrative Data including SEPP 71, SEPP 14 and SEPP26 mapping and NPWS
Estate.

Folder 7 - Community Stakeholder Consultation

Folder 8 - Management Options
Plate 3 Screenshot from GIS showing drainage network and Wallagoot catchment boundary.
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1.1. Importance of Study Area
Both Wallagoot Lake and Bournda Lagoon are iconic South Coast beauty spots which are valued highly
by local residents and visitors for their recreational and conservation values.
From an aquatic biodiversity perspective, the NSW Far South Coast ICOLLs and small estuaries are
critical aquatic habitat for 70% of species on the Eastern Australian seaboard at some stage in their life
cycle. Wallagoot is particularly important because it of its unique hydrology, with a very low opening
frequency.
Both estuaries’ catchments are home to a number of species listed under the NSW Threatened
Species Conservation Act (1995) including Potoroo, Powerful Owl, Yellow-bellied Glider; and Hooded
Plover. Significant parts of both catchments are protected in Bournda National Park and Bournda
Nature Reserve. - See Table 9
1.2. Location of Study Area
Wallagoot Lake and Bournda Lagoon are located on the far south coast of NSW between the townships
of Merimbula and Tathra, see Figure 1.
Figure 1 Location map - Wallagoot catchment - red; Bournda Lagoon catchment - mustard
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Bournda EEC
Existing
Caulerpa
netting
closure area
Figure 2 Wallagoot Lake - Caulerpa zone
1.3
Public access
at Wallagoot
Lake Boat
Ramp
Community Uses of the Catchments
There is a low density of settlement in both catchments with limited infrastructure. Wallagoot Lake Road
becomes inundated during infrequent flood events triggering the need for artificial opening of the lake
by BVSC.
Wallagoot Lake and Bournda Lagoon catchments have approximately 4400ha of National Park and
Nature Reserve; 1900 ha of these catchments is other Crown Land and Freehold Land. Limited
numbers of stock are found in both catchments including beef and dairy cattle, horses and goats. In
some places there is unrestricted stock access to the lake and tributaries, which has a detrimental
impact on riparian zones. Most of Wallagoot Lake however, is protected from stock and Bournda
Lagoon is in the National Park.
Wallagoot Lake
Bournda Lagoon
30.12
33.16
Park/Nature 20.52
23.42
Area (km2)
National
Reserve
Other
Crown
freehold
land, 9.6
% National Park/Nature 68
Reserve
9.74
71
Table 1 Land-use comparison
The catchment area values in Table 1 were calculated using ArcMap with estimated catchment boundaries.
There are some differences between previously reported figures for Wallagoot Lake with the catchment areas
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varying between 26km2 and 35km2.Both reserves are covered by a Plan of Management (NSW National
Parks and Wildlife Service, 2000).
Bournda National Park is a very popular destination for tourists and local residents. Recreational
facilities include the Wallagoot Lake Boat Ramp, the Wallagoot Lake Boat Club and a range of visitor
facilities provided by NPWS. Toilet facilities at the camping ground have recently been converted to
pump-outs so there is low risk to the estuaries from sewerage related to park visitation.
Recreational uses of the area include sailing, kayaking, water-skiing, swimming, fishing, bushwalking,
camping, bike-riding and bird-watching. Excellent water quality is an important to participants
particularly where primary contact is involved.
The recreational and natural attractions of the National Park make the area ideal for environmental
education programs. Bournda Environmental Education Centre (EEC) has been running programs in
both catchments since 1976 and the high level of interest in education and research is reflected in
participation in catchment education events coordinated by the EEC.
Wallagoot Lake is closed to commercial fishing for part of the year (1st May- 31st October) with
prescriptions on the types of nets allowed; there is only one commercial operator. Bournda Lagoon is
not open to commercial fishing and netting is prohibited.
1.4
Cultural Values
There is a rich history of cultural heritage in the region with archaeological evidence of several
thousand years of indigenous occupation. Both catchments contain Aboriginal Land managed by the
Bega Local Aboriginal Lands Council.
Plate 4 Panoramic view of the open Wallagoot Lake, March 2012. Photo by: Tony Hastings WLBC
1.5
Identification of Key Stakeholders
A number of key stakeholders are involved in the management and use of these catchments and are
listed in Table 2 below
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Table 2: Management stakeholders identified
Stakeholder
Area
NSW National Parks and
Wildlife Service, Office of
Environment and Heritage
Bega Local Aboriginal Land
Council, NSW National Parks
and Wildlife Service,
Bega Valley Shire Council
Bournda National Park
Bournda Nature Reserve
Comments
and Legislated under the National Parks and
Wildlife Act 1974, management of
catchment area, Plan of Management 2000
Aboriginal lands within the Legislated under the National Parks and
Wallagoot
and
Bournda Wildlife Act 1974, Aboriginal Land Rights Act
catchments; Aboriginal sites
1983, management of Aboriginal sites
Rural freehold and residential
Planning and development laws impact
ecosystem health and resilience, BVSC
CLEP adopted 2012
Southern Rivers Catchment Management of catchment issues Ability to develop on ground works to reduce
Authority
such as erosion and sediment catchment issues
control
Department of Primary Industry Management
of
marine Research activities, manage
NSW Fisheries
ecosystem from the low tide mark Commercial and recreational fishers impact
on fish numbers and diversity. Fisheries
Management Act 1994.
Local community
Both estuaries and surrounding Continued recreational use of area for
beach and dune system
swimming, boating and fishing, appreciation
of conservation values
Local businesses
Recreational areas attract tourism Access to recreational, natural and cultural
values
Educational Institutions
Ecological significant habitats Access to scientific, natural and cultural
such
as
seagrass
beds, values for educational and research
threatened or endangered biota purposes., Bournda EEC operates within
and EEC’s
Bournda National Park
NSW Office of Water
Water Licenses
Water Management Act 2000
NSW Government
Policy and strategy
Coastal Policy 1997, State Rivers and
Estuaries Policy 1993, Estuary Management
Policy 1992 and Diffuse Source Water
Pollution Strategy 2009. Other State
legislation; Native Vegetation Act 2003,
Species Conservation Act 1995, Protection
of the Environment Operations Act 1997,
Environment Planning and Assessments Act
1979.
Local landholders
Management of freehold land
Possible rehabilitation sites located on
private property, management of native
vegetation.
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1.6
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Community and Stakeholder Consultation
Listed below are the values, management issues and priority actions identified at a
community catchment event on 24th June 2011.
Values –What do we value about Wallagoot Lake and Bournda Lagoon Catchments?
 Important habitat for wildlife.
 Lack of human footprint.
 Visual aesthetics.
 Natural vegetation.
 Educational values and opportunities at Bournda EEC
 Science and research values.
 Recreational opportunities.
 Nice place to live.
 Quiet and peaceful.
 Lack of development
 Unique values of particular habitats or environments E.g. ICOLLs, dune lakes etc.
 Nesting site for threatened and endangered shorebirds
Community concerns/Management Issues
 Limit development pressures within the catchment.
 Control invasive species including Caulerpa, Fire weed and rabbits.
 Prevent algal blooms and protect water quality (waste water- septic leaching).
 Identification of erosion sources.
 Fencing off stock from creeks and re-vegetating riparian vegetation.
 Improve baseline data relating to vegetation, water quality and biodiversity.
 Impacts of climate change.
 Illegal activities within the catchment, rubbish dumping, motor bikes, etc.
 Manage fishing pressures.
 Reductions in biodiversity including commercial and recreational fishing species.
 Increased jellyfish populations resulting in reduced visitor numbers/tourists.
 Issues associated with the closure of Wallagoot Lake entrance.
 Issues associated with manually opening the lake entrance.
 Lack of information/education about impacts of entrance opening with regard to
water quality and the ecological role of ICOLLs in coastal ecosystems.
 Need to identify entrance opening “triggers”.
 Access for equipment required for entrance opening and protection of Aboriginal
sites.
Priority for Actions
 Identification of sediment sources/erosion hotspots.
 Collection of baseline data including vegetation, water quality and biodiversity.
 Sealing of the road on the northern side of Wallagoot Lake to reduce erosion and
improve water quality.
 Investigate options for reducing illegal activities such as rubbish dumping along Red
Hill road.
 Ensure communication between various agencies involved in the management of
Wallagoot Lake and
Bournda Lagoon catchments.
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

2.
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Continued publicity of the project to ensure key landholders are involved including
Aboriginal Land Council.
Promote the values of ICOLLs such Wallagoot Lake and Bournda Lagoon.
Explore funding opportunities and costs required to undertake some of the actions
identified within the Rapid Catchment Assessment.
Estuary Health
Coastal Lakes and ICOLLs in southern NSW have a number of different pressures on them. Increased
development of catchments means increased stormwater and effluent management issues. Increased
recreational usage also increases pressures on coastal lakes; with boating having a big impact on
seagrass meadows.
The Wallagoot Lake entrance has been open from March – June 2012 and the influx of marine waters
will potentially lead to an abundant prawn harvest later in the year. A high level of prawning activity has
the potential to have a significant impact on seagrass beds. With increased activity there is a continued
need for the Wallagoot Caulerpa Response Group to remain active in community education about the
risks of aquatic weeds.
2.1
Physical characteristics
According to the ANZECC classification system (ANZECC, 2000) Wallagoot Lake and Bournda lagoon
are tidal and wave dominated estuarine systems, when open to the ocean. Wallagoot Lake is the only
estuary in the region that remained closed during the Feb-March 2010 and Feb 2011 Flood Events. It
has been closed for approximately 13 years. It was artificially opened on 2 nd March 2012 and remains
open at the time of writing of this report (June 2012) .Bournda opens 2-3 times per year, but is
generally closed.
Plate 5 Quadrat/Transect study of seagrass – Zostera spp.
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Table 3: Estuary Characteristics of Wallagoot and Bournda
Estuary Characteristics
Water body
Wallagoot
Bournda
Entrance
location
Latitude (ºS)
-36.79
-36.92
Longitude (ºE)
149.96
149.94
Catchment area (km2)1
26.5**
34.5
Estuary area (km2)1,2
4.0
0.1
Estuary volume (Ml)3
5342.4
26.7
Average depth (m)4
1.4
0.3
Roy et al. (2001) classification5
IV/8/B
IV/8/B
Entrance condition6
I
I
Notes:
Derived from DECCW (2010) NSW estuaries and coastal catchments spatial database.
Includes area mapped as open water (see note 1), mangrove and saltmarsh areas (Creese R. G., Glasby T. M., West G. and Gallen C.
(2009) Mapping the habitats of NSW estuaries. Industry & Investment NSW Fisheries Final Report Series 113. Port Stephens, NSW,
Australia.
Based on areas at 0.6 m AHD (Roper T., Creese B., Scanes P., Stephens K., Williams R., Dela-Cruz J., Coade G. and Coates B. (2011)
Assessing the condition of estuaries and coastal lake ecosystems in NSW. Office of Environment and Heritage, Sydney).
Estimated by dividing the total volume at 0.6 m AHD by the total surface area of the estuary including mangrove areas but excluding
saltmarsh (Roper et al., 2011)
Estuary group: I = oceanic embayment, II = tide dominated estuary, III = wave dominated estuary, IV = intermittently closed estuary V =
freshwater
bodies
Estuary type: 1 = ocean embayments, 3 = drowned valley estuary, 5 = barrier estuary, 6 = barrier lagoon, 7 = interbarrier estuary, 8 =
saline coastal lagoon, 9 = small coastal creeks, 11 = brackish barrier lake. Evolution stage: A=youthful, B=intermediate, C=semi-mature,
D=mature.
(P. S. Roy, R. J. Williams, A. R. Jones, I. Yassini, P. J. Gibbs, B. Coates, R. J. West, P. R. Scanes, J. P. Hudson and S. Nichol (2001)
Structure and Function of South-east Australian Estuaries. Estuarine, Coastal and Shelf Science 53, 351-384)
Entrance conditions: O = open, T = trained, I = intermittent.**Catchment area for Wallagoot Lake appears to be an underestimate.
A comparison of catchment characteristics is given in Appendix B
Due to their small catchments, lower rainfall and wave dominated environments, these estuaries are
particularly sensitive to human activity as all catchment inputs are captured and held when the
entrances are closed. Bournda Lagoon has a small volume and a relatively large catchment, and is
particularly susceptible to disturbance, taking several months to process inputs and establish a healthy
ecosystem balance. During the last severe drought period from 2005-2010 Bournda Lagoon
experienced episodes of macro-algal blooms which affected water quality and recreational use. This
indicates the sensitivity of the estuary to extreme events and its vulnerability to catchment disturbances.
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Plate 6 Bournda Lagoon – Sept 2007, Note algal blooms.
2.2
Estuary Biodiversity
Wallagoot Lake has seagrass beds which cover most of the lake’s boundary area. The drought, which
ended in February 2010, caused the area of seagrass meadow to shrink. Following the lake filling in
February 2010 the seagrass meadows have begun recolonisation of these edge areas. The beds start
10-15m in from the edge of the waterbody. The February 2010 floods failed to open the entrance, but
deposited a large load of silt on the beds, which also further diminished the seagrass area and
productivity. Species identified include; Zostera, Ruppia megacarpa and Halophila australis. Saltmarsh
is listed as present around Wallagoot Lake but was not assessed by this study.
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Figure 3 Aquatic vegetation communities in Wallagoot Lake, 2009.
Image courtesy of Trevor Daley, Department of Primary Industries
Genetic biodiversity of Eastern Australia’s oceanic species is enhanced by the action of these ICOLLs.
As populations are closed off for differing lengths of time and then released into marine waters as
entrances are opened, biodiversity is maintained. Wallagoot Lake is unique in its offering to the genetic
pool simply because it is closed for longer than any of the other lakes nearby.
Recruitment of aquatic species and, providing habitat for development of juveniles into adults is a key
role of NSW South Coast ICOLLs, including Wallagoot and Bournda. Each lake in the series of ICOLLs
has different catchment hydrology, rates of sediment movement, riparian zone biodiversity and
estuarine hydraulics, which result in differing times of opening and, a wide range of habitat types and
aquatic species that utilise them.
Department of Primary Industries (DPI) are currently conducting research on Wallagoot Lake,
comparing fish species and assemblages with Durras Lake, another South Coast lake North of
Batemans Bay, that was recently artificially opened (NSW DPI, Pending). Research on stocking
Wallagoot Lake with King Prawn spat for recreational fishing was conducted by UNSW Researchers
and DPI in 2008-09 (Suthers, Iain University of NSW, 2008)
NPWS Merimbula has identified over 70 species of birds just in the Wallagoot Lake surrounds. A
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herbarium, compiled by botanist Dane Wimbush is now available online due to the work of volunteer
Steve Burrows. The herbarium includes over 340 species of plants from the Wallagoot Lake and
Bournda Lagoon catchments; more specimens are still to be added. (Bournda EEC, 2012)
Plate 7 Wallagoot Lake – Entrance – in open condition, 13th June 2012
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Table 4 Species diversity and abundance in Wallagoot, compiled by Luke Brown (Bournda EEC)
Species
Scientific Name
Common name
Abundance/
location
Girella tricuspidata
Acanthopagrus australis
Acanthopagrus butcheri
Rhombosolea tapirina
Atherinidae
Platycephalus fuscus
Arenigobius bifrenatus
Pagarus auratus
Arenigobius sp.
Pomatomus saltrix
Hyporhamphus regularis
Syngnathidae
Mugliadae cephulus
Anguilla australis
Anguilla reinhardtii
Luderick/Blackfish
Yellowfin Bream
Black Bream
Flounder
Hardy Heads
Dusky Flathead
Bridled Goby
Snapper
Goby sp.
Tailor
River Garfish
Pipe Fish
Sea Mullet
Short finned Eel
Long finned Eel
Upper estuary & fresh
Lower estuary
Upper estuary
Lower estuary
Lower estuary
Lower/Upper estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Upper estuary & fresh
Lower estuary
Upper estuary & fresh
Upper estuary & fresh
Upper estuary & fresh
Haliaeetus leucogaster
Haematopus fuliginosus
Haematopus longirostris
Alcedo asurea
White Bellied Sea Eagle
Sooty Oyster Catcher
Pied Oyster Catcher
Azure Kingfisher
Anas castanea
Hirundo neoxena
Ardeola ibis
Chestnut Teal
Welcome Swallow
Cattle Egret
Lower estuary & coastal
Lower estuary & coastal
Lower estuary
Upper & lower estuary
& fresh
Upper estuary & fresh
Upper estuary & fresh
Coastal
Paridotea ungulata
Amphipoda Sp
Palaemon intermedius
Penaeus plebejus
Sea Centipede
Beach Hopper
Red spotted Shrimp
King Prawns
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Catostylus mosaicus
Aurelia aurita
Mosaic Jelly
Moon jelly
Anadara trapezia
Austrocochlea porcata
Soletellina Sp
Buccinidae Sp
Batillaria australis
Trochidae Sp
Tellinidae Sp
Idiosepius notoides
Euprymna tasmanica
Anadara trapezia
Laternula marilina
Polinices sordidus
Pyrazus ebeninus
Sydney cockle
Zebra winkle
Sunset Shell
Little Whelk
Southern mudwhelk
Top Shell
Tellin Shell
Pygmy Squid
Dumpling Squid
Bimbula
Fragile Bivalve
Leaden moon snail
Hercules club whelk
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Lower estuary
Ascidia sydneiensis
Sydney Ascidian
NSW
or
Federal listed
Fish
Avian (Birds)
Crustaceans
Jellyfish/Cnidaria
Molluscs
Ascidians
Two Gems Draft Catchment Action Plan
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Vulnerable
Endangered
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Threatened Species
Wallagoot and Bournda Lake catchments are host to a number of rare and endangered species, as per
the Threatened Species listings, put out by NSW Office of Environment and Heritage (see full listing in
Appendix A) Listings and the EPBC Listings (Federal). Most of the vulnerable species have Recovery
Plans, or Action Plans. See Table below:
According to NPWS the reference to Wallagoot Lake in the Koala Recovery plan refers to sightings
from several decades ago and that almost certainly, if accurate, was a dispersing animal, possibly from
a long way away. (Pers.comm. Chris Allen, NPWS, 18th June 2012)
Table 5 Recovery Plans Relevant to Wallagoot Lake
Species
Southern Giant Petrel (Macronectes halli &
giganteus)
Grey-headed flying fox (Pteropus poliocephalus)
Koala (Phascolarctos cinereus)
Little Tern (Sterna albifrons)
Pied and Sooty Oystercatchers
Hooded Plover
Green and Golden Bell Frog
Barking Owl
Bush Stone Curlew
Yellow bellied glider
Plan
National recovery plan for Albatrosses and Giant-petrels 2011-2016
(2001)
Draft National Recovery Plan for the Grey-headed Flying Fox
(Pteropus poliocephalus) 2009
Recovery Plan for the Koala (Phascolarctos cinereus) 2008
Little Tern (Sterna albifrons) Recovery Plan 2003 and South Coast
Shorebird Recovery Program 2008-09 Breeding Season
South Coast Shorebird Recovery Program 2008-09 Breeding Season
South Coast Shorebird Recovery Program 2008-09 Breeding Season
Green & Golden Bell Frog Litoria aurea (Lesson 1829) Recovery Plan
2005
Recovery Plan for the Barking Owl Ninox connivens 2003
Recovery Plan for the Bush Stone-curlew Burhinus grallarius 2006
Recovery Plan for The Yellow-bellied Glider (Petaurus australis) 2003
3.
Ecosystem Health and Stressors
3.1
Estuary Health Pressures and Stressors
The following pressures on estuary health were identified as affecting Wallagoot Lake and Bournda
Lagoon






Rural Development and possible loss of critical riparian habitat
Catchment run-off from agricultural land with increase nutrient inputs
Unrestricted livestock access to tributaries
Recreation and tourism pressures including impact of prawning on seagrass beds in
Wallagoot Lake
Land clearing for further development and road construction with increased soil loss.
Impact of aquatic weeds including Caulerpa taxifolia
Other risks to ecosystem health include high intensity wildfires (as mentioned above); natural climatic
events such as floods and extended droughts, particularly when coupled with a closed entrance; high
nutrients and low water levels could lead to eutrophication and ecosystem damage. Wallagoot Lake
was assessed having a moderately low vulnerability with current catchment usage, which is very good
compared to similar reference sites within the state (DLWC, 2000). Bournda Lagoon, despite being
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within the boundaries of National park, was rated as highly vulnerable due to a combination of
catchment land-use, a large catchment area and a small lagoon.
The State of the Catchments (SOC) 2010 pressure indicator scores for Wallagoot and Bournda of 4.4
and 4.6 respectively are rated as very low with a trend index of unknown (NSW DECC, 2010). Given
proposals for developments in both catchments, and changes under the BVSC Comprehensive Local
Environment Plan (BVSC, 2010), that trend would appear to be certain to become one of increasing
pressure. Long-term closure of the entrance with a developed and rural catchment is a key stressor as
all run-off is captured and held in the main basin.
The Healthy Rivers Commission Independent Inquiry into Coastal Lakes (NSW HRC, 2002) assessed
Wallagoot and Bournda as shown in the table below:
Coastal
Lake
Natural
Sensitivity
Wallagoot
Very High
Bournda
Extreme
Existing
(Stress)
Catchment
Condition
Largely
unmodified
Condition Recognis
ed
conservat
Lake
ion value
condition
Slightly
Moderate
affected
Near
Pristine
Pristine
Moderate
Significant other factors
Lake
Classification
Existing
patterns
of
regional settlement, natural
resources use, recreation
and tourism and their
sustainability
Existing
patterns
of
regional settlement, natural
resources use, recreation
and tourism and their
sustainability
Significant
protection
Comprehensiv
e Protection
Table 6 Table Classification of Coastal Lakes – Summary of Data. Independent public inquiry into Coastal
Lakes – Final Report 2002
Plate 8 4Feb 2010 Flood event – turbid water in Moncks Creek
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Table 7 below outlines the multiple scale characteristics linked to the lakes’ systems, which was
adapted from the Resilience Alliance Practitioners Workbook.
Table 7 Multiple Scale Estuary Health
Domain
Scale
Larger
Large
Description of Scale and Factor
Global climate change with localised
higher risk of prolonged regional
drought and more frequent floods, sea
surges and storm events.
Catchment
health
including
management of fire, native vegetation
and riparian zone clearing; Entrance
intermittently open. Prolonged local
droughts.
Focal
Water
quality,
tidal
flows,
sedimentation, cultural values and
impacts on flora and fauna of the lake
Small
Water quality of vulnerable areas such
as smaller arms/tributaries
Conservation of individual species such
as the Pied Oystercatcher
Ecological
Smaller
Larger
Large
Focal
Social
Small
Global Environmental Legislation and
Policy
State and federal legislation
Urban development and public
education, maintenance of cultural
significance of lake and health of
community
Sewerage systems and stormwater
runoff
Smaller
Urban gardens and awareness of
impact on catchment
Large
Commercial fishing
Focal
Tourism and recreational fishing
Small
Infrastructure and amenities (roads,
bridges, easements, walking tracks)
local community amenity
Smaller
Two Gems Draft Catchment Action Plan
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Processes that influence Estuary Health
Decreased flows into lake, with occasional destructive
high flows leads to decreased oxygen levels, increased
algal blooms and Eutrophication. High rainfall events
further increase nutrient loads into lake system.
A full flush occurs when a flood event opens the mouth;
but floods threaten infrastructure and aquatic habitat.
Catchment health impacts on water quality from runoff
and status of riparian zones affects aquatic ecosystem
health. Small mosaic fire regimes within Bournda
National Park & nearby rural/forested property decreases
wild fire intensity & habitat loss; helps native
germinations; drought severely impacts on ecosystems.
Water quality impacts on overall ecosystem health and
resilience of lake system, water inflows are essential for
health of whole ecosystem, tidal flows encourage
exchange of nutrients with oceanic waters and
recruitment of species into the lake
Highly influenced by agricultural runoff and status of
riparian areas.
Through active community involvement in monitoring and
health assessment, they are able to undertake
management actions on their properties to improve
habitat and protect species; control of domestic animals
and stock also helps.
Federal and State policy influenced by global policy
Local Councils must comply with State and Federal
policy such as Planning and Development
Local planning laws and educational material on human
impacts on ecosystem. Access to employment, health
and education. Community awareness. Demographic
changes.
Conversion to systems which won't impact on water
quality (sewerage upgrades). Being aware of stormwater
impacts on water quality through project participation and
communication.
Planting local, native plants for wildlife, removal exotic
pest species, decrease in green waste dumping,
decrease in use of chemicals on garden and sweep up
debris and dispose of properly.
Overexploitation or destructive harvesting methods can
lead to species or habitat loss
Impacts on habitats and water quality (motorised boating
and recreation impacts to seagrass beds, walking on bird
nests, not aware of what fish species can be taken and at
what age/size). Possibility of exotic species introduced.
tourism impacts can be moderated by signage and
pamphlets
Increased infrastructure increases the impact of human
activities
fishing, walking, boating and swimming
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3.2
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Coastal Risks – Climate Change - Overview
Climate Change Impacts - Overview
The potential impacts of climate change on the far south coast of NSW are high with vulnerability to
frequency and intensity of drought, severe storms (greater soil erosion), bushfire events and extreme
temperatures. It has also been projected by DWE that a decrease in mean annual rain runoff of
between 0-20% will have consequences for water quality on the South Coast. (DWE, 2008)
Figure 4 Trend in Annual Total Rainfall 1970-2011 – Bureau of Meteorology (BOM, 2012)
Figure 5 Trend in Mean Temperature 1970-2011 – Bureau of Meteorology (BOM, 2012)
Figure 4 and Figure 5confirm a pattern of decreasing rainfall and increasing temperature for the region.
Climate Change Risks Specific to Wallagoot Lake and Bournda Lagoon
Floods and storms are predicted to increase, which will put pressure on the small amount of
infrastructure around the lake. Wallagoot Lake Road, the Wallagoot Lake Boat Club and nearby
houses are most at risk. Flooding of Wallagoot Lake Road during infrequent flood events is the trigger
for artificial opening of the lake by BVSC.
A sea level rise of 40-80cm by 2100, now the standard accepted risk for the South Coast of NSW
according to the NSW Department of Planning, would make this infrastructure more vulnerable to
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extreme events.
In the short to medium term the impacts have the potential to be quite detrimental; decreased rainfall is
likely to increase the duration of entrance closure with increased vulnerability to eutrophication. Long
term sea level rise, coupled with higher intensity storms and floods could have a positive impact on
ecosystem health in the lake, as the entrance could widen allowing exchange in some of the back
waters that rarely experience tidal flushing.
Figure 6 Wallagoot Lake – Coastal Risk mapping based on BVSC 2010 LEP mapping –See GIS Folder 3
Figure 7 Bournda Lagoon Coastal Risk Mapping – BVSC 2010 – See GIS – Folder 3
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4.
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Ecosystem Health Assessment and Plans
4.1
Estuary Health Assessment
Ecosystem health was assessed via regular (monthly) and event water quality monitoring, combined
with habitat assessment at three sites. The NSW State of the Catchments Report (NSW DECC, 2010)
stated that the following parameters are to be used in assessing estuarine condition and the Two Gems
project collected information on those in bold type:



4.2
Eutrophication; microalgae, chlorophyll a and turbidity levels
Habitat changes; seagrass, saltmarsh and mangrove extent
Fish assemblages; diversity, abundance, function as a nursery and integrity of food web
Ecosystem Health Experimental Design
Water Quality Testing
Regular water quality testing of parameters such as temperature, pH, turbidity, faecal coliforms,
electrical conductivity (salinity), dissolved oxygen and available phosphate were undertaken by
Bournda EEC staff, members of the Wallagoot Landcare Group (WLG), community members and
visiting school students. Parameters were collected using well established sampling procedures under
the supervision of a water quality consultant. Three sites were monitored; two at Wallagoot Lake and
one at Bournda Lagoon. Ad-hoc testing was done at other sites during major events.
Other information contributing to an understanding of estuary health was collected during:




Biodiversity surveys to evaluate species presence and abundance – see Table 4
Rapid Catchment Assessment surveys (See GIS resource)
Monitoring seagrass health
Monitoring and control of Caulerpa taxifolia
Caulerpa taxifolia is highly invasive, introduced seaweed. Once it is established within estuaries,
Caulerpa can impact upon native species including seagrass, fish and invertebrates and may reduce
the health and diversity of the aquatic environment. Caulerpa taxifolia was first discovered in Wallagoot
Lake in 2007 and control efforts have been successful in preventing the spread of the weed. This weed
is very difficult to control and can regenerate quickly from small fragments. The control program has
seen the area affected by the Caulerpa reduced from hundreds of square metres to zero through a
combination of salt application and hand weeding. The positive situation at Wallagoot Lake has been
due to the sustained efforts (2007-2010) of the Wallagoot Caulerpa Response Group (WCRG), made
up of staff from Bega Valley Shire Council, Bournda Environmental Education Centre, National Parks
and Wildlife, Southern Rivers Catchment Management Authority and local Fisheries Officers,
coordinated by the Dept of Industry and Investment Aquatic Biosecurity Unit. Local community
members have assisted with survey work and reporting of sightings. An ongoing community education
program is essential to help protect other catchments from Caulerpa. (NSW DPI, 2011)
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Sampling Methods
Water samples are collected from the edge of the waterway, using an extendable long-handle pole, to
allow collection approximately 2-3m in from the bank; at a depth of 20-25cm. Temperature is taken
immediately after collection and a DO sample collected in a separate bottle from the same site. DO
analysis is via the Modified Winkler Titration. Samples are filtered before conducting analysis of
orthophosphate. A filtered blank of sample water is used for comparison of all reacted samples by the
La Motte SMART 2 Colorimeter. Sites were selected in 2011 by scientific officers to measure
catchment inputs, collect 12 months of baseline data and assess ecosystem health changes over a 12
month period.
5. Ecosystem Health and Water Quality Status
5.1
Data collected
Faecal coliforms, pH and available phosphate levels are all within the parameters for estuary health
(ANZECC, 2000). In some cases dissolved oxygen levels tested were lower than expected and
continued monitoring would necessary to investigate this issue further.
Turbidity levels were generally low but as expected higher turbidity levels were recorded during flooding
events and periods of heavy rain. Temperature and conductivity levels naturally fluctuated with
seasonal and tidal variation and hydrological changes associated with the opening and closing of the
estuary mouths.
Bournda Lagoon Conductivity. µS/cm
60000
50000
40000
30000
20000
10000
0
Figure 8 Salinity, expressed as electrical conductivity – units are micro Siemens per centimetre.
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Wallagoot Lake Dissolved O₂ mg/L
10
8
6
4
2
0
Figure 9 Dissolved Oxygen Levels, Wallagoot Lake, Jan 2011-May 2012
5.2
Estuary Health Status
Water Quality testing within Bournda Lagoon and Wallagoot Lake indicates water quality within both
water bodies is considered to be in good condition and in line with standards outlined by the Australian
and New Zealand Guidelines of Fresh and Marine Water quality (ANZECC). The findings for Wallagoot
are generally consistent with recent unpublished studies by Bega Valley Shire Council (Yee, Nick Elgin
Associates, 2010) and the State of the Catchment 2010 condition indicator score of 4.6 which is rated
in the best condition category (NSW DECC, 2010). The studies on water quality for Wallagoot is also
consistent with previous studies done by ANU students in recent years (Claydon, 2010) however no
data for Bournda Lagoon is indicated in the 2010 State of the Catchment report. Stratification of
Wallagoot Lake has been confirmed (Claydon, 2010) (Yee, Nick Elgin Associates, 2010) and this may
have important implications for entrance opening.
Wallagoot Lake’s health according to the physiochemical and biological monitoring data was assessed
as being slightly to moderately disturbed (ANZECC, 2000) The level of protection for slightly to
moderately disturbed ecosystems is for maintenance of biodiversity to be set as the key management
goal and this is consistent with proposals for restoration of riparian vegetation.
DO% is influenced by temperature and impacted by algal-bloom fuelling nutrient loads, particularly
dissolved phosphate (orthophosphate) and dissolved nitrogen (nitrate and ammonia). Possible sources
of nutrients in the catchment of Wallagoot Lake are non-point sources from agricultural production
(stock grazing), possible septic tank leakages and natural sources such as clay soils, which usually
have higher levels of Phosphate, Iron and Manganese.
The biggest impact at the local scale appears to be from dissolved nutrients entering the lake system,
particularly orthophosphate, which attaches readily to fine clay particles that are carried in with
catchment run-off. The Rapid Catchment Assessments identified areas in both catchments where
removal of riparian vegetation has resulted in bank erosion leading to higher levels of turbidity than in
undisturbed sections of the catchment.
With the catchments being managed by multiple institutions, summarised in Table 1, adaptive
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management strategies could be usefully applied, refer to Figure 10
5.3
Data management
As water quality data is captured it is stored on the NSW Waterwatch Online Database. Bournda
Environmental Education Centre is the only group currently set up to do this in the Bega Valley Shire.
The results are available online at
www.waterwatch.nsw.gov.au
Regular/Quarterly Quality Assurance assessments are conducted by Water Scientist, Suzzanne Gray.
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Experimental Design - Adaptive Management Model for Wallagoot Lake
 Biological surveys undertaken by education institutions,
marine centre, community groups or interested
stakeholders
 Ongoing community physiochemical monitoring
 Marine, fauna and flora surveys to monitor changes in
abundance, diversity and health
 Include new research into management plan
 Revaluate priority rankings annually
Evaluate and
Monitor
Outcome
maintain and enhance water
quality and ecosystem health
Review and adjust
 Rank priorities in order of
ecological and conservation
value (high, medium or low)
 Rank in order of achievability
Priorities and
Implement
 Define strategies in line with funding or resourcing
constraints
 Continually develop community and educational institutional
relationship to deliver programs
Establish
Measures
 Review monitoring of water quality
and species diversity and abundance
 Review priorities are appropriate as
system changes or impacts change
Define
strategies
Develop
objectives
Figure 10 Adaptive Management Model (Resilience Alliance and Santa Fe Institute, 2004):
Two Gems Draft Catchment Management Plan
 Sulisit Consulting 2012






 Species abundance, habitat and diversity
 Resilience to perturbations such as climate change or
visitor use
 Nursery ground for surrounding locations supporting
commercial and recreational fishers
 Ability to support a diversity of species including rare or
endangered species and endangered ecological
communities
Improve water quality values
Protection of habitat
Educate community and visitors of the value of estuarine habitats particularly seagrass beds
Share knowledge with wider community particularly local schools
Collaborate with stakeholders
Include Aboriginal knowledge, skills and culture
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5.4
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Estuary seagrass and habitat monitoring
Seagrass habitat monitoring consisted of a survey of presence or absence of mapped species in a range of
sites. More rigorous assessment of the seagrass extent and health proved to be problematic with several
planned events being cancelled due to poor visibility due to high turbidity levels from flood events and windy
conditions.
Plate 9 Wallagoot Lake during the drought, with seagrass beds exposed (January, 2009, Bournda EEC)
Table 8 Bournda-Wallagoot Waterwatch Group/Wallagoot Landcare
Group Members as at June 2011
Doug Reckord (Bournda EEC)
Luke Brown
Bob Harris
Jan Lynch
Ed and Viv Wildsoet (Residents)
Neil Fisher (Residents)
Suzzanne Gray (Water Quality Consultant)
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6. Conclusions (including potential management actions)
Wallagoot Lake and Bournda Lagoon are two very special estuaries in the Southern Rivers Catchment
Management Area. Current indications are that estuary health is in good, if slightly disturbed condition but that
there are increasing pressures on these wonderful natural areas which are so highly valued by the community
for a multiplicity of purposes
The Rapid Catchment Assessment proved to be an excellent tool for considering some of the key pressures on
the estuaries and was effective in identifying sites where riparian vegetation has been removed or is in poor
condition. There are areas where stock access tributaries of the estuaries and discussions need to take place
with the relevant landholders on fencing. Both main tributaries (Moncks Creek and Sandy Beach Creek) have
large sediment slugs which require management to protect the lower estuaries but it is not clear what strategies
would be best applied in these settings. It is possible that extraction of sediment in the past occurred at different
sites but an expert assessment of these sites is recommended.
Landholders, whose properties were included in the Rapid Catchment Assessment process, are willing to
discuss on-ground rehabilitation works but have made no commitments beyond that. There is excellent potential
for erosion control, revegetation and fencing works to improve the catchment condition. (See GIS Folder 2)
The engagement of community in estuary monitoring promotes learning and a greater awareness of human
impacts, thereby building in ecosystem resilience, which is crucial to long-term estuary health. The assistance
provided by this project has allowed consistent monthly monitoring of water quality parameters which is
important for understanding estuary processes. One conclusion from the water monitoring project is to shift the
sampling focus, from the relatively stable mid-estuary sites on Wallagoot Lake, to sites in the upper estuary and
tributaries, including Moncks Creek. This will give a better indication of impacts of damaging activities in the
catchment as the large volume of the lake buffers the response at the sample sites. There are limitations to this
however, as Moncks Creek only flows intermittently. (See GIS Folder 3)
In Wallagoot Lake seagrass species are recolonising areas exposed by drought conditions in 2006-2010
however further efforts need to made to establish systematic monitoring of seagrass extent and health. During
these surveys there was no evidence of any further Caulerpa taxifolia infestation and no control measures were
required. If no further sightings are made by February 2012, NSW DPI will move to have the lake declared
Caulerpa free which will be a considerable achievement by the Wallagoot Caulerpa Response Group. (NSW
DPI, 2011)
Community input to the draft estuary management plan indicates a high level of support for catchment
management that protects the natural values and water quality of both estuaries. The catchments contain a
stunning diversity of flora and fauna, including many threatened and vulnerable species, and have been
formally identified as vulnerable and suitable for significant (Wallagoot) and comprehensive protection
(Bournda) (NSW HRC, 2002) Protection of these natural heritage and conservation values was identified by
community participants as a major reason for contributing to monitoring and research efforts.(GIS Folder 4)
A community geographic information system, or GIS, has been established using Google Earth and captures a
range of information useful to the management of these catchments. The use of a freely available GIS platform
means that information can be shared with community members for them to explore and study. There is
intense interest in the management of these estuaries from a wide range of user and interest groups and it
makes sense to use a range of
technologies to enhance communication about estuary
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processes and management. An exciting development during the project has been to map major vegetation
types and link that data with the Bournda Online Herbarium which contains over 340 specimens. It is hoped
that this will be a useful resource for the management of native vegetation by landholders. Mapping of erosion
risk and important habitat are also planned. These maps will be developed from existing resources available
from various agencies.
The key to maintaining the health of Wallagoot Lake and Bournda Lagoon is limiting detrimental development,
encouraging best practices for agricultural and rural-residential activities within the catchments; and ensuring
multiple stakeholders are adequately resourced to implement adaptive management approaches. The
challenge facing land managers and the community is to identify a set of management outcomes that prevent
poorly considered development and ad-hoc catchment management that results in degraded estuarine
environments. Information on planning policies applying to different parts of the catchments can be viewed in
GIS Folder 5
Both estuaries need protection from eutrophication, sedimentation and habitat disturbance and there are
concerns that excessive and/or poorly managed development will compromise the high conservation status of
both estuaries. The presence of erodible soil types in the catchment mean that land clearing and erosion of
roads and road side batters on leading to land degradation processes that put these estuaries at risk. Plate 1
clearly illustrates the threats from clearing and development and the need for good road and drainage design.
Further examples can be found in GIS Folder 2.
Estuary Management Process
While this combined Draft Estuary Management Plan provides some valuable information on estuary processes
and community input, there is a need to establish for a more comprehensive estuary management process.
The Estuary Management Process can be considered as 8 distinct steps, although in some cases these steps
can be combined especially for small estuary systems (NSW DNR).
1.
Form an Estuary Management Committee
2.
Assemble Existing Data
3.
Carry Out an Estuary Process Study
4.
Carry Out an Estuary Management Study
5.
Prepare a Draft Estuary Management Plan
6.
Review Draft Estuary Management Plan
7.
Adopt and Implement the Estuary Management Plan
8.
Monitor and Review
This report, while carrying the title of “Draft Estuary Management Plan” may be more correctly called a draft of a
Draft Estuary Management Plan or an Interim Draft Estuary Management Plan as key elements are not fully
completed and were outside the scope of the Two Gems project. Looking at the 8 step process above, it is
clear that some parts of Steps 2, 3, 4 and 5 have been achieved while none of the steps could be considered
complete. In particular there is a need for a collaborative effort to identify recommended management options,
schedules and costings.
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P a g e | 30
There are a large number of environmental studies, in both catchments, including those from Council road
works, the BVSC Estuary Management Process, NPWS fire management and university research that need to
be assembled into a coherent and useful form. There is a significant opportunity here for an integrated
approach with Bournda EEC, NPWS, Bega Valley Shire Council and SRCMA working together on this strategic
task in close consultation with the local community.
Key recommendations:

Bournda EEC and Wallagoot Landcare host a workshop with the BVSC Coastal Planning and
Management Committee to discuss the project’s findings and discuss completing a comprehensive
Estuary Management Process for each estuary.

Bournda EEC, NPWS, Southern Rivers CMA and other relevant stakeholders, including the Aboriginal
community, work through the BVSC CPMC to develop separate Draft Estuary Management Plans for
Wallagoot Lake and Bournda Lagoon

Begin negotiations with willing landholders for rehabilitation of riparian vegetation, control of erosion
and management of sediment plugs.

Identify additional resources to more effectively collate existing studies and information on baseline
estuary processes, including input from community members.

Collate key research data on water quality and biodiversity into individual catchment databases.

Provide support for ongoing water quality monitoring in both catchments.

Further investigate suitable management of erosion prone landscapes including identifying soil erosion
risk mapping.

Conduct an audit to determine if the BVSC Local Environment Plan is consistent with the coastal lakes
sustainability assessments, in accordance with Dept. of Planning guidelines (NSW DNR, 2006)

Provide support for ongoing water quality monitoring in both catchments.
Two Gems Draft Catchment Action Plan
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Wallagoot/Bournda Estuary Health Brief
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APPENDIX A
Table 9 Threatened Species List – Bournda Lagoon/Wallagoot Lake Catchments
Threatened Species
Amphibia
Giant Burrowing Frog
Green and Golden Bell Frog
Littlejohn’s tree frog
Avian
Terrestrial
Barking Owl
Brown treecreeper
Bush Stone Curlew
Eastern Ground Parrot
Flame Robin
Gang-gang Cockatoo
Glossy Black Cockatoo
Little Eagle
Little Lorikeet
Masked Owl
Powerful Owl
Olive Whistler
Regent Honeyeater
Scarlet Robin
Sooty Owl
Spotted Harrier
Square-tailed kite
Superb Fruit Dove
Swift Parrot
Varied Sittella
White fronted Chat
Sea and Shore Birds
Australasian Bittern
Black Bittern
Black Browed Albatross
Black-tailed Godwit
Comb-crested Jacana
Gibson’s Albatross
Great Knot
Hooded Plover
Little Tern
Masked Booby
Northern Giant Petrel
Osprey
Pied Oystercatcher
Providence Petrel
Shy Albatross
Sooty Oystercatcher
Southern Giant Petrel
Varied Sittella
Two Gems Draft Catchment Action Plan
 Sulisit Consulting 2012
Scientific Name
Heleioporus australiacus
Litoria aurea
Litoria littlejohni
Legal
NSW
Status
Vulnerable
Endangered
Vulnerable
Ninox connivens
Climacteris picumnus
Burhinus grallarius
Pezoporus wallicus wallicus
Petroica phoenicea
Callocephalon fimbriatum
Calptorhynchus lathami
Hieraaetus morphnoides
Glossopsitta pusilla
Tyto novaehollandiae
Ninox strenua
Pachycephala olivacea
Xanthomyza phyrgia
Petroica boodang
Tyto tenebricosa
Circus assimilis
Lophoictinia isura
Ptilinopus superbus
Lathamus discolour
Daphoenositta chrysoptera
Epthianura albifrons
Vulnerable
Vulnerable
Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Critically Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Endangered
Vulnerable
Vulnerable
Botaurus poiciloptilus
Ixobrychus flavicollis
Thalassarche melanophris
Limosa limosa
Irediparra gallinacean
Diomedea gibsoni
Calidris tenuirostris
Thinornis rubricollis
Sterna albifrons
Sula dactylatra
Macronectes halli
Pandion haliaetus
Haematopus longirostris
Pterodroma solandri
Thalassarche cauta
Haematopus fuliginosus
Macronectes giganteus
Daphoenositta chrysoptera
Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Critically Endangered
Endangered
Vulnerable
Vulnerable
Vulnerable
Endangered
Vulnerable
Vulnerable
Vulnerable
Legal
Federal
Status
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Endangered
Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Endangered
Vulnerable
Wallagoot/Bournda Estuary Health Brief
Wandering Albatross
Mammalia
Australian Fur Seal
Eastern Bentwing Bat
Eastern False Pipistrelle
Eastern Free-tail-Bat
Grey Headed Flying Fox
Golden Tipped Bat
Greater Broad-Nosed Bat
Southern Right Whale
Humpback Whale
Marsupials
Brush tailed Phascogale
Eastern Pygmy Possum
Koala
Long nosed Potoroo
Squirrel Glider
Spotted tailed Quoll
Southern Brown Bandicoot
Yellow bellied glider
Plants
Australian Saltgrass
Narrow-leafed Wilsonia
Matted Bush-pea
Square Raspwort
Threatened Ecological Communities
Coastal salt marsh
Baumea juncea, Juncus krausii,
Sarcocornia quinqueflora, Sporobolus
virginicus, Triglochin striata, Isolepis
nodosa, Samolus repens, Selliera
radicans, Suaeda australis and Zoysia
macrantha.
Freshwater
wetlands
on
coastal
floodplains
P a g e | 32
Diomedea exulans
Endangered
Arctocephalus
pusillus
doriferus
Miniopterus
schreibersii
oceanensis
Falsistrellus tasmaniensis
Mormopterus norfolkensis
Pteropus poliocephalus
Kerivoula papuensis
Scoteanax rueppellii
Eubalaena australis
Megaptera novaengliae
Vulnerable
Phascogale tapoatafa
Cercartetus nanus
Phascolarctos cinereus
Potorous tridactylus
Petaurus norfolcensis
Dasyurus maculates
Isodon obesulus obesulus
Petaurus australis
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Distichlis distichophylla
Wilsonia Backhousei
Pultenaea pedunculata
Haloragis exalata subsp.
exalata
Haloragis exalata subsp.
exalata var. exalata
Endangered
Vulnerable
Endangered
Vulnerable
Located in the intertidal zone
on the shores of estuaries and
lagoons that are permanently
or intermittently open to the
sea.
Endangered
Ecological Community
Endangered
Vulnerable
Vulnerable
Endangered
Vulnerable
Vulnerable
Associated with coastal areas Endangered
subject to periodic flooding Ecological Community
and in which standing fresh
water persists for at least part
of the year in most years.
Source: NSW Department of Environment and Climate Change, NSW National Parks and Wildlife Search, Wildlife Atlas.
Two Gems Draft Catchment Action Plan
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Wallagoot/Bournda Estuary Health Brief
P a g e | 33
APPENDIX B
Table 10 Comparison of Attributes of the Wallagoot Lake/Bournda Lagoon Catchments
Characteristic
Wallagoot
Bournda Lagoon
Forest (km2)
22.9
32.7
%
86
95
Rural(km2)
3.8
1.8
%
14
5
Urban(km2)
0
0
%
0
0
Land Total (km2)
26.7
34.6
Water-way (km2)
3.79
0.06
Entrance condition
I
I
Berm Height (m)
2.83
2.07
Type
4
4
Evolution
B
B
Depth (average – m)
2.0
0.35
Ratio of Catchment to Estuary Surface Area
7.07
577
Ratio of Catchment Surface Area to Estuary Volume
(km2/km3)
3522.427
1647619
Water Level Rise from 100mm rain – forested (m)
0.3
5
Ratio of runoff volume from 100mm rain to estuary volume forested
<40
1520
Average Estuary Flushing Time from freshwater inflows –
forested (Weeks)
64
<1
Average Estuary Flushing Time from freshwater inflows and
tides – forested (Weeks)
29
<1
Annual Areal Load of Total Phosphorus – Forested
(tonnes/yr/ km 2)
<0.2
6.2 (high risk)
Annual Areal Load of Total Nitrogen - Forested (tonnes/yr/
km2)
<1
62 (high risk)
Vulnerability Score - Forested (low-robust, high-vulnerable)
13 (mod. Low)
17 (mod high)
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Characteristic
Wallagoot
Bournda Lagoon
Vulnerability Score – Current Land Uses (low-robust, highvulnerable)
13
18
Chlorophyll-a concentration (ug/l) - current
5
19
Rainfall (Ml)
32128
36519
Runoff (Ml)
6170
2871
Coefficient
0.192
0.079
Annual
Catchment
Runoff Only
Rainfall (Ml)
28127
36460
Runoff (Ml)
2169
2812
Coefficient
0.077
0.077
Entrance Closure (Weeks)
13
4
Tidal Prism P (Ml)
758
11
Beach Type
Straight-SE
Zeta
Opening Location
North
South
Annual Drift
High
Low
Drift Rate M (m 3/yr)
20000
5000
Entrance stability (P/M ratio) <20 unstable
38
2
Breakouts 1944-1999
8
49
% Time open
4
8.6
0.18
1.10
Mean
291
47
Min
73
6
Max
769
209
Annual
Runoff
Including
Direct
Rainfall
Released
782
2824
Total
6170
2871
% Retained
87.3
1.6
Annual
Catchment
Runoff Only
Released
502
2807
Total
2169
2812
% Retained
76.9
0.2
Rainfall Runoff for undisturbed
catchment
Annual
Runoff
Including
Direct
Rainfall
Opening
Freq.
Per Year
Period
between
(wks)
Trapping Efficiency - undisturbed
Two Gems Draft Catchment Action Plan
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Wallagoot/Bournda Estuary Health Brief
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Characteristic
Wallagoot
Bournda Lagoon
32128
36519
Runoff (Ml)
6450
3007
Coefficient
0.201
0.082
Annual
Catchment
Runoff Only
Rainfall (Ml)
28127
36460
Runoff (Ml)
2449
2948
Coefficient
0.087
0.081
8
56
% Time open
4.5
0.18
1.25
Mean
291
42
Min
78
5
Max
764
209
Annual
Runoff
Including
Direct
Rainfall
Released
966
2930
Total
6450
3007
% Retained
85
2.5
Annual
Catchment
Runoff
Only
Released
612
2911
Total
2449
2948
% Retained
75
1.3
Per Yr
T (wks)
Opening Freq
Breakouts 1944-1999
Trapping Efficiency for Current
Land Uses
Rainfall (Ml)
Breakout and Trapping Eff –
Current Land use
Rainfall runoff for current land
uses
Annual
Runoff
Including
Direct
Rainfall
Data from Vulnerability Assessment of Estuaries in the Eurobodalla and Bega Valley Shires, DLWC
2000
Plate 10 The future of Landcare - Participants -Two Gems
Two
Gems Draft
Landcare
CampCatchment
2011 Action Plan
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Wallagoot/Bournda Estuary Health Brief
P a g e | 37
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