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Management Opportunities for
Wolli Creek Riparian Zone
Discussion Paper
Prepared by David Frith
June 2007
Table of Contents
TOC \o "1-3" \h \z \u Part 1 - Introduction PAGEREF _Toc43956237 \h 4
1.1 Background PAGEREF _Toc43956238 \h 4
1.2 Purpose PAGEREF _Toc43956239 \h 4
1.3 Aims PAGEREF _Toc43956240 \h 4
1.4 Scope PAGEREF _Toc43956241 \h 5
Part 2 - Importance of the riparian zone PAGEREF _Toc43956242 \h 6
2.1 Definition PAGEREF _Toc43956243 \h 6
2.2 Functions of the riparian zone PAGEREF _Toc43956244 \h 6
2.3 Riparian zone width PAGEREF _Toc43956245 \h 6
Part 3 - Land managers within Wolli Creeks riparian zone PAGEREF _Toc43956246 \h 8
3.1 Northern bank PAGEREF _Toc43956247 \h 8
3.2 Southern bank PAGEREF _Toc43956248 \h 8
Part 4 - Current condition of the riparian zone PAGEREF _Toc43956249 \h 10
4.1 Vegetation PAGEREF _Toc43956250 \h 10
4.1.1 Saltmarsh Endangered Ecological Communities PAGEREF _Toc43956251 \h 10
4.1.2 Northern bank PAGEREF _Toc43956252 \h 11
4.1.3 Southern bank PAGEREF _Toc43956253 \h 11
4.2 Fauna PAGEREF _Toc43956254 \h 11
4.3 Creek bank PAGEREF _Toc43956255 \h 12
4.4 In-stream structures PAGEREF _Toc43956256 \h 12
4.5 Litter, illegal dumping and industrial storage PAGEREF _Toc43956257 \h 12
Part 5 - Statutory and strategic planning requirements PAGEREF _Toc43956258 \h 13
Part 6 - Opportunities & priorities for improvement PAGEREF _Toc43956259 \h 15
6.1 Vegetation PAGEREF _Toc43956260 \h 15
6.1.1 Southern Bank PAGEREF _Toc43956261 \h 15
6.1.2 Northern Bank PAGEREF _Toc43956262 \h 15
6.2 Fauna PAGEREF _Toc43956263 \h 16
6.3 Creek bank PAGEREF _Toc43956264 \h 16
6.4 Litter, illegal dumping and industrial storage PAGEREF _Toc43956265 \h 17
Appendix I Mapping of Alligator Weed PAGEREF _Toc43956266 \h 18
Appendix II Mapping of Ludwiga peruviana (a) PAGEREF _Toc43956267 \h 19
Appendix III Mapping of Ludwiga peruviana (b) PAGEREF _Toc43956268 \h 20
Appendix IV Relevant policies, plans and legislation PAGEREF _Toc43956269 \h 21
Appendix V Mapping of mangrove and endangered saltmarsh communities PAGEREF _Toc43956270 \h 22
Appendix VI Proposed Waterworth Park layout Canterbury CC PAGEREF _Toc43956271 \h 23
Appendix VII - Proposed Waterworth Park layout WCPS PAGEREF _Toc43956272 \h 24
References PAGEREF _Toc43956273 \h 25
Personal Communication PAGEREF _Toc43956274 \h 25
Acknowledgements PAGEREF _Toc43956275 \h 25
List of abbreviations
CCC Canterbury City Council
DIPNR Department of Infrastructure Planning and Natural Resources
NPWS National Parks and Wildlife Service
RCC Rockdale City Council
WCPS Wolli Creek Preservation Society
Introduction
Background
Wolli Creek runs from Narwee and Roselands in the inner south west of Sydney, and flows in an east- north-easterly direction until it joins the Cooks River at Tempe. It is one of the last remaining creeks with extensive lengths of natural banks in the inner parts of Sydney, making it an important natural asset and a regional resource.
The Wolli Creek valley has a history of use by humans. Middens in the Wolli Creek area indicate that Aborigines inhabited the area prior to European settlement. Since European settlement, the area has been host to farming and Chinese market gardens; a weir at Turrella a reminder of the past. A railway corridor has operated along the southern bank of the Creek since 1931, and during its development changes were made to the Creeks course.
Downstream from Bexley North, there are large areas of bushland and open grass adjoining the north bank of the Creek. Originally set aside as a road reservation for the M5 motorway, an area of approximately 50ha will soon become a Regional Park under the management of NSW National Parks. Public opposition to the motorway influenced the decision to create a tunnel for the motorway, preserving these open areas for future generations to enjoy.
Today the Creek and its surrounds are used by the community for activities such as fishing and kayaking, while it also provides pleasant scenery for picnics, bushwalks, and bird watching. The Creek is also a valuable educational resource for schools in the surrounding suburbs.
Purpose
The purpose of this Plan is:
To identify the processes that threaten the environmental and social values of Wolli Creeks riparian zone; and,
To guide future conservation and remediation activities in the riparian zone.
Aims
The aims of this Plan are to:
Conserve existing areas of high conservation value within the riparian zone;
Restore degraded sections of the riparian zone;
Enhance terrestrial and aquatic biodiversity;
Improve water quality;
Improve the visual amenity of the area; and
Increase the opportunities for education and recreation around the Creek.
Scope
This Plan focuses on the stretch of Wolli Creek running downstream from Bexley Road to the junction with the Cooks River at Tempe. This stretch of the Creek presents significant opportunities for riparian zone management, with largely natural creek banks and opportunities for vegetation management. A Plan of Management was developed on behalf of the National Parks and Wildlife Service (now within the Department of Environment and Conservation) for the proposed Regional Park on the northern bank, and has recently been approved by the Minister for the Environment ADDIN EN.CITE Clouston2004116CloustonNSW National Parks and Wildlife Service, Regional Parks UnitWolli Creek Regional Park Plan of Management2004SydneyClouston(Clouston 2004), The Service also commissioned a comprehensive 5 Year Bushland Regeneration Operations Plan ADDIN EN.CITE Perkins200012126Perkins, IWolli Creek Regional Park: 5 Year Bushland Regeneration Operations Report2000SydneyIan Perkins Consultancy Services, June 2000(Perkins 2000). Hence this plan will primarily address the management of areas outside the Regional Parks boundaries. Nonetheless, the two sides of the creek clearly have to be considered as a unit and work on them should be co-ordinated for efficiency and success.
Four management issues relating to the riparian zone will be addressed:
Vegetation;
Fauna;
Creek banks; and
Litter and illegal dumping.
Information for this Plan was gathered through a review of available literature, correspondence with local councils, community groups and landholders, and a number of site visits to the Wolli Creek area.
Importance of the riparian zone
Definition
The riparian zone can be defined as the area of land adjoining a creek that influences the interaction between terrestrial and aquatic environments ADDIN EN.CITE Lovett19994428Lovett, S.,Price, P.,Riparian Land Management Technical Guidelines, Volume One: Principles of Sound Management1999CanberraLand and Water Resources Research and Development Corporation(Lovett and Price 1999).
Functions of the riparian zone
Riparian zones serve a number of functions, including ADDIN EN.CITE Lovett19994428Lovett, S.,Price, P.,Riparian Land Management Technical Guidelines, Volume One: Principles of Sound Management1999CanberraLand and Water Resources Research and Development CorporationKMC20047743KMCRiparian PolicyKu-ring-gai Council2004(KMC 2004; Lovett and Price 1999):
Buffering against pollutants entering watercourses;
Limiting erosion;
Controlling light and temperature;
Providing aquatic and terrestrial food and habitat;
Providing regional links between habitat patches; and,
Providing an aesthetic visual buffer in urban environments.
The riparian zone is often the most fertile and productive part of the landscape. It generally has wetter soils due to its low position in the landscape and supports a unique and abundant diversity of vegetation and fauna ADDIN EN.CITE Lovett19994428Lovett, S.,Price, P.,Riparian Land Management Technical Guidelines, Volume One: Principles of Sound Management1999CanberraLand and Water Resources Research and Development Corporation(Lovett and Price 1999).
The management of riparian zones is particularly important in urban landscapes for a number of reasons:
Urban areas have large areas of impervious surfaces, creating high volumes of fast flowing stormwater, which can have an effect on creek bank stability and cause erosion;
There are higher pollutant loads in stormwater runoff from sources such as road oil and garden fertilisers, highlighting the need for a well functioning riparian zone to act as a buffer;
Riparian vegetation is often one of the few remaining areas of habitat for local species in urban environments; and,
Small and fragmented areas of riparian vegetation are more susceptible to invasion by noxious and exotic weeds.
Riparian zone width
There is no set width of riparian zones. The width of the riparian zone varies depending on local conditions such as flow variability, valley setting and sediment type ADDIN EN.CITE KMC20047743KMCRiparian PolicyKu-ring-gai Council2004(KMC 2004).
When planning to manage riparian zones, the width can be determined according to the purpose of the riparian zone. A DIPNR study into riparian corridor management placed riparian zones into three categories ADDIN EN.CITE DIPNR2004996DIPNRRiparian Management Corridor Study: Covering all of the Wollongong Local Government Area and Calderwood Valley in the Shellharbour Local Governement Area.2004March 2004Prepared for Wollongong City Council by Department of Infrastructure Planning and Natural Resources(DIPNR 2004):
Category 1: Environmental Corridor Provides biodiversity linkages ideally between one key destination with another (e.g. between large patches of vegetation).
Category 2: Terrestrial and Aquatic Habitat Provides basic habitat and preserves the natural features of a watercourse (not necessarily linking key destinations).
Category 3: Bank Stability and Water Quality Limited (if any) habitat value but contributes to the overall basic health of a catchment.
As well as these functions, the riparian zone should have an adequate vegetated buffer to counter edge effects on the urban interface. There should also be a sufficient Asset Protection Zone between the buffer and any assets to protect against bushfire.
REF _Ref146467477 \h Table 1 provides details of the different natural resource management zones surrounding a watercourse.
Table SEQ Table \* ARABIC 1 Natural Resource Management Zones ADDIN EN.CITE DIPNR2004996DIPNRRiparian Management Corridor Study: Covering all of the Wollongong Local Government Area and Calderwood Valley in the Shellharbour Local Governement Area.2004March 2004Prepared for Wollongong City Council by Department of Infrastructure Planning and Natural Resources(DIPNR 2004)
Natural Resource Management ZonesDetailMinimum WidthCore Riparian Zone (CRZ)A minimum width to be fully vegetated with local provenance native vegetation (including aquatic groundcovers, shrubs and other species). The minimum widths are determined by the stream category and are:
Category 1: Environmental Corridor
Category 2: Terrestrial and Aquatic Habitat
Category 3: Bank Stability and Water Quality(from top of Bank)
40m
20m
normally 10mVegetated BufferRequired to protect the environmental integrity of the CRZ from edge effects such as:
Weed invasion from adjacent lands
Micro-climate changes within the CRZ
Litter / Pollution
Trampling (from edge of CRZ)
10 m but widths vary dependent on site conditions and the stream categoryAsset Protection Zone (APZ)
Also known as Fire Protection Zone, comprised of: Inner Protection Area (IPA) and Outer Protection Area (OPA)Required to protect assets from potential bushfire damage.
The APZ is measured from the outer edge of the core riparian zone/vegetated buffer to the asset.
Depending on vegetation type and % of cover in the vegetated buffer, it may be possible to extend part of the APZ into the vegetated buffer.
Urban perimeter roads, flood conveyance areas and stormwater quality and quantity controls can form part of the APZ provided these objectives are not in conflict with or compromising of riparian outcomes.
Site dependent
Land managers within Wolli Creeks riparian zone
REF _Ref146293665 \h Figure 1 (over page) shows the major land managers in the riparian zone of Wolli Creek.
Northern bank
From mid-2007, NPWS will manage the majority of the northern bank from Bexley Road to Waterworth Park through the Wolli Creek Regional Park Plan of Management ADDIN EN.CITE Clouston2004116CloustonNSW National Parks and Wildlife Service, Regional Parks UnitWolli Creek Regional Park Plan of Management2004SydneyClouston(Clouston 2004). The exceptions are where a road and a footbridge cross the creek. Active vegetation management (weed & rubbish removal, planting of local-provenance indigenous plants) occurs throughout the Park with the assistance of local community group, the Wolli Creek Preservation Society, and the support of Canterbury City Council, NPWS and financial support from three State Government grant schemes. Volunteer labour from the Society, Conservation Volunteers Australia, and corporate partners, plus work by professional bush regeneration teams are used in various combinations. (Peter Stevens, pers. comm.).
Waterworth Park, near the junction of Wolli Creek and the Cooks River, is managed by Canterbury City Council. The park is primarily managed for recreational values rather than environmental values, according to the Councils Open Space Plan of Management. While the Council does have specific plans for individual parks, there is no such plan for Waterworth Park (David Bell, pers. comm).
Southern bank
Rail Corp manages the East Hills rail corridor that extends along the southern bank of Wolli Creek. Rail Corp undertakes weed and animal control measures within their operational zone (within 5m of any infrastructure), but not outside this zone. There is 7.5 ha of Rail Corp land adjacent to the Creek that are beyond the operational zone, and therefore not subject to weed and animal control by Rail Corp ADDIN EN.CITE Willoughby2004886Willoughby, HelenLetter to Wolli Creek Preservation Society, 22 October 20042004SydneyRailCorp(Willoughby 2004). The rail corridor restricts access to riparian zone on the southern bank, protecting it from degradation by direct human use.
Rockdale City Council manages two narrow strips of land adjacent to the Creek at the industrial estate at Turrella and the RSL Club. RCC sprays weeds in these areas, but this work is not part of any broader riparian strategy (J. Comerford, pers. comm.).
A small parcel of waterfront land currently owned by the Department of Planning, but for sale, is located close to the Henderson St footbridge in Turrella, adjacent to the industrial estate there.
Figure SEQ Figure \* ARABIC 1: Major land managers in the riparian zone of Wolli Creek between Bexley Road and the Cooks River.
SHAPE \* MERGEFORMAT SHAPE \* MERGEFORMAT
Current condition of the riparian zone
The riparian zone has undergone modification at various times particularly with the building of the railway in 1931 and its expansion in 1999. Other significant changes were the straightening of the creek at Bardwell Park in 1952 with the building of the road bridge, and the raising of land levels under the industrial estate and Turrella Reserve in response to flooding. As a narrow valley Wolli has always been subject to flooding in major rain events. However, since the 1930s, the increased number of houses, a trend of increasing land areas for individual houses, and the replacement of extensive areas of parkland by the M5E Motorway, have seen an increase in the frequency of flooding and ongoing change to the hydrodynamics of the stream.
With the increased hard surfaces noted, rain runoff travels much faster and with much less ground absorption. The result has been a long-term shift from a stream which flowed well for long periods, fed by slow release of absorbed water, towards one which flows at very high levels during rain and rapidly reduces to a very low flow afterwards. Some of this effect may be mitigated by recent changes that have mandated rainwater retention systems for new buildings and the beginning of a return to domestic rainwater tanks on older properties.
The high flow events increase the erosive potential of the stream and also bring nutrients, rubbish, weed seeds and other material carried in stormwater to much higher levels of the valley than in the past.
There has also been a history of sewage overflows from the sewer which runs down the northern bank of the creek. Wolli Creek Preservation Society is aware of at least three overflows from one point alone over the 12 month period to October 2006. In October 2006, raw sewage contaminated a 5 kilometre stretch of the Creek with unknown impacts on local ecosystems ADDIN EN.CITE WCPS200614146WCPSLetter to the Minister for Water Utilities2006October 2006Wolli Creek Preservation Society(WCPS 2006). Sewage alters the nutrient balance of the riparian zone and creek, enhancing the ability of weeds to proliferate. It also introduces possibly harmful and toxic substances into the local ecosystems, potentially harming terrestrial and aquatic fauna. This is a serious issue that needs to be addressed.
Vegetation
Vegetation in the riparian zone varies in type, quality and quantity along the length of the Creek. Its high levels of weed species, particularly vines, reflects the presence of high levels of nutrients in stormwater, the presence of relatively abundant water, and the availability of continuing supplies of seeds and other propagates from the existing weeds and carried in stormwater from the surrounding streets and gardens. The Sydney Central Weeds Committee has mapped the riparian areas affected by the growth of two declared noxious weeds, Alligator Weed (Alternanthera philoxeriodes) and Ludwigia (Ludwigia peruviana) (Appendix I & II), which significantly affect both the Northern and Southern banks.
Saltmarsh Endangered Ecological Communities
Saltmarsh communities, listed as threatened communities under the Threatened Species Conservation Act 1995 (NSW), exist on the creek banks towards the Creeks lower reaches (see Appendix V). A recent report highlighted the importance and significance of these saltmarsh communities ADDIN EN.CITE CERS200613136CERSCooks River Ecological Monitoring Program Phase II. Vegetation Mapping and Benchmark Data for Macrophyte and Invertebrate Indicators2006Final Report, Centre for Environmental Restoration & Stewardship, Australian Catholic University, October 2006(CERS 2006). The report noted the rare groupings of species found in the areas studied, with the presence of both salt tolerant and salt intolerant species. The report identified the areas within Wolli Creek as being the most significant saltmarsh stands in the Cooks River estuary, and that they would be ideal locations for monitoring the effects of predicted marine incursions over the coming decades.
Northern bank
The width of vegetation adjacent to the Creek is significant on the northern bank extending up to several hundred meters from the Creek bank, providing important habitat as well as an environmental corridor in the landscape.
Areas within the proposed Regional Park are primarily bushland of varying quality, with some of it very high quality, as well as wetlands, open grass, and mangrove and endangered saltmarsh communities ADDIN EN.CITE Clouston2004116CloustonNSW National Parks and Wildlife Service, Regional Parks UnitWolli Creek Regional Park Plan of Management2004SydneyClouston(Clouston 2004). The riparian zone is more significantly affected by weeds than areas higher up the valley side.
Waterworth Park is primarily an open grassed area containing four sporting fields and a velodrome (www.canterbury.nsw.gov.au). There is also significant vegetation coverage within the park, however vegetation adjacent to the Creek is fragmented. There is a walking track that runs within the core riparian zone, and a narrow grassed area between the track and the creek.
A recent outbreak of Pampas Lily-of the Valley (Salpichroa sp.) has been identified at Bardwell Park (Peter Stevens, pers. comm.).
Ludwigia in the Bray Avenue wetlands is currently being removed under funding from the Sydney Central Weeds Committee through Canterbury City Council.
Southern bank
The width of vegetation adjacent to the Creek on the southern bank is generally much narrower than that on the northern bank. At two places where rail infrastructure intersects the Creek there is no vegetation, however a section at Turrella is almost 200 metres wide at one point. Despite the frequent narrowness, most of the riparian zone on the southern bank could provide important terrestrial and aquatic habitat, while also maintaining bank stability and water quality. Little is known of the underlying terrain, which has been impacted by the railway embankment and by subsequent flooding, as it is not easily accessible and is overgrown predominantly by weed vegetation.
Weeds are a large problem along the creek line and railway corridor with dominant species including Privet, Lantana, Blackberry, Crofton Weed, Tradescantia and Morning Glory ADDIN EN.CITE Clouston2004116CloustonNSW National Parks and Wildlife Service, Regional Parks UnitWolli Creek Regional Park Plan of Management2004SydneyClouston(Clouston 2004). These are a problem also on the northern bank. But there are also weeds currently on the southern bank that have yet to take hold on the northern bank, including the giant grasses, Pampas Grass and Arundo Grass.
Fauna
The area is rich in birdlife, providing habitat or a resting place for over 25% of the bird species recorded in NSW as a whole ADDIN EN.CITE Rankin200611116Rankin, NeilNeil Rankin's Birds of Wolli Valley2006SydneyWolli Creek Preservation Society(Rankin 2006).
Large reptiles including red-bellied black snakes, eastern snake-necked turtles and eastern blue-tongue lizards have often been sighted around the Creek ( HYPERLINK "http://www.wollicreek.org.au" www.wollicreek.org.au)
There have been a number of sightings of foxes around Wolli Creek ( HYPERLINK "http://www.wollicreek.org.au" www.wollicreek.org.au). Foxes have been listed as a key threatening process under the Threatened Species Conservation Act 1995.
Bandicoots have been positively identified by NPWS staff in nearby Dulwich Hill, although occasional suggestive diggings in the Wolli Valley have not yet been confirmed.
Creek bank
The majority of the creek bank is natural, except where road and rail infrastructure intersects the creek. This leaves the creek bank vulnerable to erosion if appropriate vegetation is not maintained in the riparian zone. Willows are frequent along the creek bank and have the potential to block it as well as altering the pattern and balance of nutrients added to the stream. However, if removed, careful planning will be required to maintain creek bank stability.
In-stream structures
There is a weir at Turrella that currently acts as a barrier to fish passage between the lower and upper stretches of the Creek. The weir has been identified by NSW Fisheries as a priority for action, and the Sydney Metropolitan Catchment Management Authority has provided a grant to Canterbury City Council and Rockdale City Council for the construction of a fish ladder. A Statement of Environmental Effects is underway and a Development Application should be lodged early in 2007. A condition of the CMA funding is that improvements are made in the riparian zone downstream of the weir (David Bell, pers. comm).
Litter, illegal dumping and industrial storage
A large amount of litter accumulates in the riparian zone and the Creek as a result of stormwater runoff transporting street litter.
A number of areas in the riparian zone are frequently used to dump rubbish, including on Council land at the end of Henderson St., Turrella, and on RailCorp land at Bardwell Park. There are also considerable residues of past extensive dumping on the northern side of the creek, sometimes within the riparian zone, as at Bray Avenue, Earlwood. As well as the obvious visual impact that this has, the dumping of garden waste can aid the spread of weeds and other materials may contain toxic substances and/or excessive nutrients.
Industrial material is often stored in the riparian zone in both the rail corridor and the industrial park at Turrella. It is probable that, during rain and, especially, flood events, substances leach from these piles and enter the soil and water.
Sewage overflows have occurred on a number of occasions from the sewer running along the northern bank (Peter Stevens, pers. comm.). As well as health and safety issues, overflows increase the availability of nutrients to both terrestrial and aquatic plants, generally favouring weeds species over native species and increasing the risk of algal blooms.
Statutory and strategic planning requirements
Appendix III lists the policies, plans, strategies and legislation that are relevant to the management of Wolli Creeks riparian zone. REF _Ref154412887 \h Table 2 on the following page gives a summary of some of the key aims of these instruments that are most relevant to the management of Wolli Creeks riparian zone.
Table SEQ Table \* ARABIC 2 Key aims of documents relevant to the management of Wolli Creeks riparian zone
AreaTopicLegislation/StrategyRequirementsVegetationEndangered Ecological CommunitiesTSC Act 1995Protection of Coastal Saltmarsh communities in the Sydney Basin BioregionNoxious WeedsNoxious Weeds Act 1993Land holders required to remove noxious weeds from their landRiparian corridorsSydney Metropolitan Catchment Action PlanNet improvement in the health of modified waterways and riparian corridors (Catchment Target W1)FaunaInvasive speciesSydney Metropolitan Catchment Action PlanThe impact of invasive species on biodiversity is reduced by decreasing the number, distribution and impact of pest animals (Catchment Target B5)FoxesTSC Act 1995/ NSW Threat Abatement Plan Predation by the Red FoxPublic authorities to take appropriate action to implement measures in threat abatement plansCreek bankWeirSydney Metropolitan Catchment Action PlanPriority fish barriers removed or modified (Management Target W 1.1)ErosionSydney Metropolitan Catchment Action PlanMinimise sediment load inputs to urban bushland and waterways through best practice erosion and sediment control strategies (Management Target LD1-1)Litter/dumping/storageLitter and illegal dumpingProtection of the Environment Operations Act 1997
Waste Avoidance and Resource Recovery Strategy 2003Regulation of pollutant sources
Reduce tonnage of litter and legally dumped material reported annually by regulatory agencies and RID squads
Opportunities & priorities for improvement
Vegetation
With only two key managers involved on each side of the creek, a high level of coordination of vegetation management along the banks of Wolli Creek should be possible. On the southern side there needs to be active management of vegetation with the aim of a long term improvement in the environmental value of the riparian zone. The aim should be the reconstruction as far as possible of a cover of vegetation that is compatible with and supportive of the native plant communities on the northern side, effectively extending the area of native habitat in the valley. This could be achieved by progressively reducing weeds and planting indigenous species.
Southern Bank
There are opportunities for Rockdale City Council to facilitate vegetation reconstruction work within the narrow riparian zone adjacent to the RSL and the Turrella industrial estate, and to encourage the adjacent landholders to progressively add relevant native plantings within their own holdings, in preference to exotic species.
Within RailCorp land, the reconstruction aim would be restricted to the maximum that could be achieved consistent with the need for rail safety. Work here would require safe access for volunteer and professional workers to RailCorp land outside its operational zone. This could be provided by installing appropriate temporary or permanent fencing. A more limited solution might be providing appropriate supervision on specified days. However, there are unlikely to be sufficient days of track maintenance closure for this to allow for the amount and seasonal pattern of the bush restoration work required.
A key need for coordination is in the timing of management actions in the riparian zone. Removing weeds from one side of the creek while leaving them on the other is unlikely to achieve desired outcomes, even in the short term. Because of the natural direction of weed spread under the influence of gravity and water flow, work should broadly proceed downstream from Bexley Road, taking in both sides of the creek. Staging of weed removal will also be important to ensure that at all times there is adequate cover and food for native animals, plants and invertebrates. The Wolli Creek Preservation Society has plans to use long-stem tubestock plantings of native species of local provenance as a prelude to progressive willow reduction. Such sequencing will be essential to maintain bank stability and protect them from erosion as willows are removed or die.
Northern Bank
The Plan of Management for Wolli Creek Regional Park includes extensive plans for weed control, feral animal control and bush regeneration plans to improve the quality and connectivity of vegetation within the Parks boundaries. It also identifies opportunities to coordinate activities with adjacent land managers, including those on the Southern bank. There is an opportunity to build on these initiatives for other land managers in the area.
As noted earlier there is no plan of management for Waterworth Park. However, Canterbury City Council has received two conflicting proposals for changes to the use of the park. The first of these, from the Touch Football Association, is for an expansion of the playing fields from 4 to 10, with removal of most of the mature trees in the central part of the park and intrusion into the vegetation in the riparian zone. The second proposal, from the Wolli Creek Preservation Society, while allowing for the addition of three further fields, retains many more of the central trees and puts forward a restoration plan for the riparian, moving the existing path further away from the creek, eliminating the mown area strip there, and progressively expanding the native vegetation in the zone by replacing the weeds and low quality bush with locally-provenanced natives and replacing some of the existing grassed area of the park.
There is a major opportunity to repair and enhance the vegetation in the riparian zone of Waterworth Park so that it complements and supports the vegetation upstream. This opportunity would be substantially compromised if the full six playing fields proposal were allowed to proceed. Canterbury City Council is the sole landowner with respect to the park, and has yet to make a decision on the future of the park.
Fauna
Habitat for native fauna could be improved through the vegetation management activities outlined above.
While the impacts of feral animals in the Wolli Creek area are unknown, they do present a threat to native wildlife and any possible return of, for instance bandicoots, to the area. There are limited possibilities for fox control because the narrowness of the valley and the proximity of housing rules out, under current regulations, both shooting and poisoning with 1080 baits. Foxes are proving too smart for any conventional trapping. The southern bank, which is inaccessible to the public and generally to dogs as well, is one area where baiting could be considered, although a specific exemption would be needed for this to occur. However, this would be of limited value unless part of a regional program to control fox numbers, as they would readily return from adjacent populations. If foxes were to be removed, it might create a greater problem with feral cats, which they ae thought currently to control. Further education of the public on reducing fox access to food and shelter is being planned by a group of local Councils. Ongoing efforts are also needed in educating residents on the impact of domestic cats.
Creek bank
Given the creek banks primarily natural condition, maintaining stability and minimising erosion is of primary concern. Any vegetation management strategies need to consider the impact on creek bank stability. As noted earlier the timing of planting versus weed removal, particularly willows, needs to be carefully co-ordinated. In some areas, stabilisation techniques, such as the use of matting, may assist in binding the banks while new growth develops. The major problem for the creek banks lies in the changed hydrodynamics of the creek discussed earlier (section 4). Slowing down the rate of stormwater discharge to the creek is beyond the scope of this plan, but an important matter to be addressed by State and Local Government authorities.
Litter, illegal dumping and industrial storage
Public education on the fate and effect of litter dropped in streets, shopping centres etc has to be a major part of programs to reduce litter in streams generally. There is scope through the involvement of the two local Councils (plus Hurstville City Council, upstream of Kingsgrove Road) to work more intensively with local businesses to bring this issue to constant attention, eg through signage in commercial areas noted for litter, such as shopping centres and strips and car parks. However, there will always be a residual resistant group in the community that will continue to litter.
Gross pollution removal devices will therefore continue to be needed. There is a major Sydney Water device just off-stream on the western side of Bexley Road, but this device suffers from occasional lapses in clearing and maintenance. Some form of litter trap is required ideally on all significant stormwater catchments draining to the creek and there are some projects in process to achieve this for particular sections. For example, on the northern side of the creek, Canterbury City Council has received a Commonwealth grant to allow traps to be installed in a major drainage catchment entering bushland near the end of Richard Avenue, Earlwood and a smaller project under a State grant obtained by the Council in conjunction with the Wolli Creek Preservation Society will see a litter trap and a sedimentation trap for stormwater entering the wetland at Bardwell Park. A wider long-term programme is needed in relation to stormwater entering from both sides of the creek, extending upstream beyond Bexley Road and including Bardwell Creek.
The rising cost of proper rubbish disposal has added a financial incentive to those who engage in deliberate bulk dumping of rubbish in bushland and other areas adjacent to the creek. Education will leave a residual resistant group here too, and measures are needed to discourage dumping. Improved fencing at known and new dumping sites can restrict access and increase difficulty in some areas. Councils commitment to rapid removal of dumped material needs to be maintained. This could be supplemented by improved systems for public notification of dumped material and the identification of those responsible.
Storage of industrial materials on land within or close to the riparian zone needs review with a view to improved practices and the removal of potentially problematic materials. Both RailCorp, in relation to its own land, and Rockdale City Council, in relation to the Turrella industrial estate, could undertake such a review. Industrial storage further upstream such as that at Kingsgrove industrial estate could also impact on downstream water quality, and needs to be addressed at a later date.
Appendix I Mapping of Alligator Weed
Mapping of Alligator Weed in Wolli Creeks riparian zone (Source: Sydney Weeds Committees)
SHAPE \* MERGEFORMAT
Appendix II Mapping of Ludwiga peruviana (a)
Mapping of Ludwiga peruviana in Wolli Creeks riparian zone (Source: Sydney Weeds Committees)
SHAPE \* MERGEFORMAT
Appendix III Mapping of Ludwiga peruviana (b)
Mapping of Ludwiga peruviana in Wolli Creeks riparian zone (Source: Sydney Weeds Committees)
Appendix IV Relevant policies, plans and legislation
Relevant policies and plans
AuthorityPolicy/plan/strategyYearSydney Metropolitan Catchment Management AuthoritySydney Metropolitan Catchment Action Plan2006NSW GovernmentSydney Metropolitan Strategy2006Sydney Metropolitan Catchment Management Authority; Sydney Weeds CommitteesWeed Management Strategy for the Sydney Metropolitan Catchment2006Resource NSW (Department of Environment and Conservation)Waste Avoidance and Resource Recovery Strategy2003Cooks River Regional Working PartyCooks River Foreshores Strategic Plan1997NSW National Parks and Wildlife ServiceWolli Creek Regional Park Plan of Management2004
Relevant legislation
TitleYearJurisdictionThreatened Species Conservation Act1995NSWNoxious Weeds Act1993NSWRivers and Foreshores Improvement Act1948NSWProtection of the Environment Operations Act1997NSW
Appendix V Mapping of mangrove and endangered saltmarsh communities
Mapping of mangrove and endangered saltmarsh communities in the lower reaches of Wolli Creek
Appendix VI Proposed Waterworth Park layout Canterbury CC
Appendix VII - Proposed Waterworth Park layout WCPS
References
ADDIN EN.REFLIST CERS (2006), Cooks River Ecological Monitoring Program Phase II. Vegetation Mapping and Benchmark Data for Macrophyte and Invertebrate Indicators. Final Report, Centre for Environmental Restoration & Stewardship, Australian Catholic University, October 2006.
Clouston (2004), Wolli Creek Regional Park Plan of Management. Clouston, Sydney.
DIPNR (2004), Riparian Management Corridor Study: Covering all of the Wollongong Local Government Area and Calderwood Valley in the Shellharbour Local Governement Area. Prepared for Wollongong City Council by Department of Infrastructure Planning and Natural Resources, March 2004.
KMC (2004), Riparian Policy. In: Ku-ring-gai Council.
Lovett S. & Price P. (1999), Riparian Land Management Technical Guidelines, Volume One: Principles of Sound Management. Land and Water Resources Research and Development Corporation, Canberra.
Perkins I. (2000), Wolli Creek Regional Park: 5 Year Bushland Regeneration Operations Report. Ian Perkins Consultancy Services, June 2000, Sydney.
Rankin N. (2006), Neil Rankin's Birds of Wolli Valley. Wolli Creek Preservation Society, Sydney.
WCPS (2006), Letter to the Minister for Water Utilities. Wolli Creek Preservation Society, October 2006.
Willoughby H. (2004), Letter to Wolli Creek Preservation Society, 22 October 2004. RailCorp, Sydney.
Personal Communication
Peter Stevens Vice President, Wolli Creek Preservation Society
John Comerford Rockdale City Council
David Bell Canterbury City Council
Acknowledgements
I would like to thank Peter Stevens for his help in preparing this report his intimate knowledge of Wolli Valley was extremely useful.
The author can be contacted at HYPERLINK "mailto:frith_dave@hotmail.com" frith_dave@hotmail.com.
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Management Opportunities for Wolli Creek Riparian Zone
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