Impact of Helensburgh, Otford and Stanwell Tops on their surrounding natural environment, report to DEP 1984

Photocopy of a photocopy of the first page of the original report.

Photocopy of a photocopy of the last page of the original report.



National Parks and Wildlife Service



NATURAL ENVIRONMENT_________________

(NPWS report to the Department of Environment and Planning for their study and comparison of urban development proposals for Helensburgh and West Menai. This digital copy was prepared on 24th February 2011 by Bob Crombie from a photocopy of the original copy of the report.)

The Study Area

The study area includes Otford, Stanwell Tops, Blue gum Forest, Helensburgh West, Helensburgh, Lilyvale, Garrawarra Hospital and the lands surrounding these developments north to Waterfall and McKell Avenue including parts of Royal National Park

Water Catchment

The study area is almost wholly contained within the Catchment area of the Hacking River. A small area on the western edge drains into the MWSDB Woronora Water Catchment Area.
Major tributaries receiving runoff from the developed lands include:

a)     The Hacking River itself

b)    Gill’s Creek

c)     Gardiner’s Gully

d)    Camp Gully Creek

e)     Garbage Tip Creek (drains the garbage tip and sanitary depot)

f)     Wilson’s Creek

g)     Cawley’s Creek

All of these creeks drain into the Hacking River which then flows north through Royal National Park and out into Port Hacking.

Resume of Royal National Park

Royal National Park is part of a statewide and national system of parks and reserves set aside to conserve outstanding scenery or natural features in an area.

These parks and reserves also:

  • Conserve viable populations of wildlife of an area
  • Conserve representative samples of a complete range of the state’s natural environments
  • Protect and preserve Aboriginal sites and objects
  • Protect and preserve areas that are the sites of buildings, objects, monuments or events of national significance
  • Provide for the promotion of public awareness, understanding and appreciation of wildlife, National Parks and culture conservation, and the importance of these to the overall quality of people’s environment.
  • Provide for regulated appropriate use and enjoyment by the public consistent with the nature conservation objectives for the area.

Royal national Park for itself conserves:

  • Representative samples of Hawkesbury Sandstone landforms, geology and soils
  • Representative samples of Narrabeen series landforms, geology and soils
  • Some samples of Wianamatta series landforms, geology and soils
  • Representative samples of Hawkesbury sandstone vegetal alliances and their associated animal life including
  • A very complex mosaic of floristic assemblages on a scale from large to small with the assemblages frequently intergrading.

This is a reflection of the very varied assemblage of sol factors (depth, structure, nutrition), drainage patterns, climatic patterns, salt spray accession, plateau dissection, altitude, aspect, fire histories and geographic location (on a biogeographic ecotone between a northern warm temperate biota and a southern cool temperate biota respectively).

Communities include a variety of heathlands, woodlands, open forests and closed forests.

  • An excellent sample of the vegetation of the area now covered by the metropolis of Sydney
  • An excellent sample of mallee heathland.
  • Representative samples of Narrabeen series rock vegetal alliances and their associated animal life.

Communities include a variety of woodlands, open forests and closed forests.

The open forests are rich in arboreal mammals and contain excellent stands of very tall trees.

The closed forests (rainforests) are very rich floristically and are a very varied assemblage with considerable intergradation at the sub-alliance and alliance level. They are part of a spectrum of rainforests along the Illawarra Escarpment and Hacking River along many environmental gradients producing a very complex and diverse array of forests of great scientific and ecological significance.

They represent the northern most limit and lowest altitude of these forests and they overlap between a northern warm temperate biota and a southern cool temperate biota. This unique geographical and biological location produces many unique and important features in the rainforest in this area.

  • A very rich variety of endangered plants and animals
  • A biologically outstanding, very varied and complex array of wildlife (described above) important ecologically, scientifically and educationally and for appropriate recreation.
  • Lands recognized as having truly national significance as a series of recreational complexes in a natural or national park setting, in particular the Hacking River, creeks, inlets and coastal foreshores are of immense value for recreation.  Very large numbers of people use the park.
  • The Hacking River as a wild river.
  • Aboriginal sites and relics of the Dharawal tribe
  • Important historic and cultural relics and traditions
  • A large tract of natural land exceedingly well placed in close proximity to and separating the large population centres of Sydney and Wollongong. This provides unique and very important scientific, recreational, educational and cultural opportunities for many people.
  • The first national park in Australia and the second in the world.

Historical Perspectives and implications

Royal National Park was dedicated as the National Park in 1879 as the first national park in Australia and the second in the world. The park reserved a large, unalienated tract of natural land rich in natural resources and natural features very suitable for the preservation of nature “to show perpetually what Australian vegetation is capable of,” “as a place for recreation and enjoyment” and as “lungs for Sydney” to purify its air and provide a place of healthful retreat for Sydneysiders.

At this time, the National park was part of a vast tract of land continuous with the Illawarra Escarpment and coastal lowlands to the south, with the Water Board and Army lands to the south and west and with vast tracts of natural and crown land to the north west.

This continuity ensured the safety and survival of the wildlife in the park.

Ijn 1934, the Garrawarra range was secured as a reserve for public recreation. This was added to the park in 1967.

Between 1970 and 1973 the National parks and Wildlife Service investigated lands around Helensburgh and Otford and recommended acquisition and addition of these lands to Royal National Park. The area recommended included the lands east of Helensburgh encompassing Herbert’s Creek, Gardiner’s Creek, Cedar Creek, Stuart’s Gully and the lands north of Camp Gully Creek.

The process of acquisition was begun for these lands, however, an unfortunate clerical error resulting from promotion and transfer of the staff member handling these matters, resulted in this process being sent into files and consequently no further action was taken. The error was not discovered until 1982. Until this time, the management of the South Metropolitan District of the National Parks and Wildlife Service had been resting easy on this matter in the false belief that much pf the land was secured for the Service and only awaiting release from t he objections raised by mining interests before it would be acquired and added to the park. The falsity of these beliefs and the error from which they resulted was not discovered until 1982.

Over the years since its inception, and increasingly more so recently, considerable change in land use of the lands neighbouring Royal National Park has occurred. There has been an increasing number of urban, industrial and rural developments many of which have had a significant effect upon the park and its use.

Many established land uses in the areas neighbouring the park require study and control as it is now recognized that they have had slow and steady accumulative impacts which have only recently become apparent. Further study will undoubtedly reveal the true extent of this problem

Since 1975, State, Regional, and Local Government planning requirements have changed considerably. The Environmental Planning and Assessment Act, 1979, h as made it mandatory for the Service to fully appraise the potential impacts caused by its own projects. The Service will continue to appraise potential environmental impacts of proposals initiated by other authorities and persons which impinge upon the Service’s responsibilities.

Royal National Park has a Plan of Management which was adopted b y the Minister in 1975. However, many important management issues that were not foreseen in 1975 now need specific planning and many others require more detailed provisions than the 1975 Plan contained.

The appearance of these new issues has necessitated a review of the 1975 Plan and the concomitant preparation of a new (draft) Plan of Management. This process of review of the Plan of Management will be an important task of the park managers and it will be done at intervals of from 5 to 10 years. The review of the 1975 Plan and preparation of the new (draft) Plan is going on now.


(a)            Historic and established changes

  1. Firewood cutting and logging of all lands in the Hacking River valley and tributary valley south of Bola Creek with emphasis upon tall open forests and rainforests.
  2. Firewood cutting and logging of all lands along the Woronora Ridge from Waterfall to Sutherland.
  3. Establishment of Javan rusa deer populations over entire study area.
  4. Considerable alterations to all aspects of the fire regime over most of the area.
  5. Fires burning rainforests and tall open forests following the aftermath of logging.
  6. Introduction of exotic plants particularly lantana and Crofton weed.
  7. Introduction of exotic animals particularly dogs, cats and foxes.
  8. Diseases affecting many marsupials in early 1900’s and dramatically reducing population levels of many species.
  9. Construction of Prince’s Highway.

10.  Construction of the Illawarra Railway Line.

11.  Urban and rural development of Otford, Stanwell Tops, Helensburgh, Waterfall, Heathcote, Engadine, Loftus and Sutherland.

12.  Sydney urban rail link to Otford established.

13.  Coal mining at Helensburgh established.

14.  Coal waste disposal in Camp Gully Creek.

15.  Helensburgh Garbage Tip and Sanitary Depot established.

16.  Garrawarra Hospital established.

17.  Strip mining for laterite on Woronora Ridge.

18.  Sand and stone mining.

19.  Mushroom mining.

20.  Minor industrial development of Helensburgh, Heathcote, Engadine and Loftus.

21.  Road and track construction throughout the area.

22.  Establishment of flora reserve on Camp Gully Creek.

(b)            Recent Land-use changes

  1. Upgrading and widening of the Prince’s Highway.
  2. Increase in traffic on the Prince’s Highway.
  3. Construction of F5 Freeway from Waterfall t o Wollongong.
  4. Upgrading, widening and electrification of the Illawarra Railway line with increased rail traffic.
  5. Further urban and rural development.
  6. Connection of sewer to Helensburgh from Waterfall (imminent).
  7. Increase in the number of service easements and constructions.
  8. Establishment of horse-riding activities around Helensburgh and Otford.
  9. Establishment of Kelly’s Falls Reserve.

10.  Increased trail-bike and 4WD vehicle activity on roads and tracks around Helensburgh.

11.  Small acre farm development between Helensburgh and Otford.

12.  Classification of the Waters of the Hacking River and its tributaries as Class “P”, Protected Waters, (Clean Waters Act).

13.  Mapping of Protected Lands Around Helensburgh (Soil).

14.  Establishment of large horse-riding companies with many horse-riding trips carried out through the bushland and illegally in Royal National Park.

(c)            Proposed Land-use Changes

a)     Increase in the size of the urban area of Helensburgh with a projected four-fold increase in the population.

b)    Further ‘rural’ development around Helensburgh.

c)     Upgrading of the water supply to the Helensburgh area.

d)    Increased industrial development of Helensburgh.

e)     Large scale urban developments of the Helensburgh area.

f)     Development of Stuart’s Gully as a coal waste dump of alternatively the Garrawarra Hospital gravel pits.

g)     Development of Helensburgh as the terminal station on the Sydney Urban Rail Illawarra Line (imminent).

h)    Increased recreational demand on Royal National Park.


The impact of the land-use changes surrounding Royal National Park has been considerably degrading to the natural environment and the environmental amenity of large areas of the Park. Some changes have had a directly obvious effect upon the Park, for example, the SRA electrification activities on the Illawarra Railway Line have contributed large loads of sediment to the Hacking River and its tributaries and caused great turbidity for often weeks at a time.

These sediment beds have been ‘fertilised’ by nutrients from many sources (Garrawarra Hospital, Otford mushroom farms, Helensburgh Garbage Tip/Sanitary Depot) and grown massive weed infestations.

However, the impacts of some of the changes are not immediately obvious and impose long term threats to many environmental values.


Royal National Park is becoming increasingly isolated from surrounding natural lands with which it previously had a connection of bush.

Urban development, railway constructions and upgrading highway and freeway construction, increased traffic on the transport services, rural and semi-rural development with their tree clearance, construction of many roads and trails, construction of cleared service easements, and many other developments act as impermeable barriers to wildlife movement and have already isolated Royal National Park from their surrounding lands except for a few corridors of varying degrees of quality which are available for the movement of Wildlife to and from the Park.

Royal National Park is approximately 15000 hectares in area and is a goodly sized reserve of natural land. However, a look at Map I (attached) will show that this 15ooo hectares is not a continuous conservation unit but is rather divided broadly into four major conservation units these being (a) a primarily woodland/low open forest unit, (b) a primarily heathland/low open woodland unit, (c) a tall open forest/rainforest unit, and (d) a unit of vegetation influenced greatly by its littoral exposure, respectively with their associated animal life.

Consequently, the effective conservation size of Royal National Park is largely dependant upon the size of these units rather than on the 15000 hectares as a whole.

The area of each of these compartments is such that it is entirely feasible for any one or more units to be catastrophically affected by fire, disease, drought, insect attack, or other circumstance or combination of circumstances with disastrous results for the wildlife in them.

Many catastrophes are of natural occurrence and historically natural environments recover from catastrophe by recolonisation from small unaffected refuges if present and by migration of species back into the affected area from adjacent unaffected lands.

However, Royal National Park is being increasingly deprived of this natural environmental safeguard as a result of its increasing isolation by developments around its perimeter.

Units A and B have recently suffered catastrophic burning, which over a number of years has affected up to three quarters of their area.

Unit C is the area under most threat as it is the smallest unit. It presently is continuous with forests outside Royal National Park east of Helensburgh, but these forests are proposed for urban and rural development and for mining purposes. The Service is presently investigating these lands as a matter of urgency for acquisition and addition to Royal National Park.

The integrity of Unit C has also been seriously compromised by logging and the intrusion of deer affecting recovery.

Therefore, throughout these lands today the area occupied by many natural habitats, and the distributional areas of many species, are undergoing two types of change. First, the total area occupied by natural habitats and by species adversely affected by Man is shrinking at the expense of human-made habitats and by species benefited by people. Second, formally continuous natural habitats and distributional ranges of human-intolerant species are being fragmented into disjunctive pieces. These processes have important consequences for the future of natural habitats and human-intolerant species.

The implications are: (1) the ultimate number of species that the area will save is likely to be an increasing function of the reserve’s area or conservation units’ areas, and their integrity.(2) the rate at which species go extinct in the area is likely to be a decreasing function of the reserve’s area or conservation units’ areas, and their integrity. (3) The relation between reserved habitat area and probability of a species’ survival is characteristically different for each species. (4) Explicit suggestions can be made for the optimal design of human intrusions to minimize the impact of these intrusions upon habitats and species.

The effective population number must also be taken into account and this is the minimum population size to which a species can fall if it is going to recover and recolonise an area, and that will retain the original genetic diversity of the species or a large fraction of it, in perpetuity and provide the genetic means for continued evolution. It must take into account natural and human-induced fluctuations, and be large enough to withstand the vicissitudes of fire, drought, disease, increased predation (dog, cat, fox, insect, etc,), etc or a combination of these. It is the lowest number that a population can fall to under these circumstances if the species is to survive.

Many species in Royal National Park have already suffered local extinction. Grey kangaroo, wallaroo, potaroo, eastern quoll, tiger quoll, koala, rock wallaby, platypus and brown phascogale are some examples.

Many other species are threatened with local extinction. For example, pademelons, red-necked wallaby, pygmy possum, squirrel glider, greater glider, yellow-bellied glider, mountain possum, coucal pheasant, emu wren, broad-headed snake, white beech, ceratin jewel beetles and some orchids.

Many of the aforementioned locally extinct and threatened species are largely dependant upon the tall open forests and rainforests of conservation unit C for their existence.

There is reserved in Royal National Park, insufficient area of tall open forest and rainforest to maintain effective population numbers of many species particularly the large mammals. Over 50% of the rainforest and tall open forest in the Hacking River Catchment is outside Royal National Park and subject to the threat of land clearance and various developments. If the integrity of these habitats and their continuity with Royal National Park were lost it can be reasonably predicted that many species dependant on these habitats in Royal national Park would be threatened with local extinction and this includes the plants as well as the animals.

Despite the very serious nature of this threat to unit C the same argument and logic applies also to the other units A, B and D and consequently the same threat.

To safeguard the natural values of Royal National Park, wildlife corridors must be established between it and the neighbouring natural land units to mitigate against the fragmentation of land into smaller natural units and to allow for movement of species between the land units as a safeguard against the effects of catastrophe and, just as important but more insidious, the effects of slow accumulative impacts.

Royal National Park requires some form of recognized, and preferably reserved, continuity with the MWSDB Catchment lands to the west and south west to safeguard units A and B and with the lands east of Helensburgh and the Illawarra Escarpment to safeguard units C and D. (See map 3 – wildlife movement corridors around Helensburgh).

As much as possible, the Service should seek to acquire these lands or seek their protection by special zoning.


The Hacking River is the major river system in Royal National Park. It and its tributaries receive drainage from many urban and rural developments around the perimeter of Royal National Park and upstream of the Park. Much of the upper catchment of the river is outside of the Park.

The waters of the Hacking River and its tributaries are classified Class “P” Protected Waters according to the Clean Waters Act.

In a great many ways the creeks and Hacking River permeates the aesthetic qualities and leisure and recreational potential of the Park. They provide the drinking water for many of the animals in the Park. They are frequently bounded by communities very sensitive to environmental disturbance such as rainforests and tall open forests.

The river and streams are highly variable in flow and for long periods of the year may be stagnant or slowly flowing.

Accessibility to the Hacking River is good and swimming in its waters is, or rather was until recently, a popular activity. Boating in the backed up waters of Audley Weir is a very popular leisure activity.

The Hacking River is being forced to receive wastes in increasing quantities from many land use changes within its catchment and these wastes are having a considerable detrimental effect upon water quality for animal drinking, human contact, leisure and recreational use, and aesthetic appreciation. The river has very little assimilative capacity to absorb these wastes and they are released into it without any concern about the possible effects of these wastes on the environment. These waters have seriously disrupted the Park management systems and involved them in time and money consuming control activities.

Large volumes of liquid wastes are an inevitable consequence of human settlement. The proper disposal of these wastes is a complex and costly exercise. If the upper catchment of the Hacking River is allowed to be developed further for rural and urban purposes, an increasingly large, up to massive discharge of liquids bearing wastes to the water environment must occur. There can be no possible expectation that wastes can be eliminated or that accidents, negligence or criminal acts will not occur, and that environmental damage will be avoided. The river and its tributaries must be degraded more as a consequence throwing and enormous on-going burden of cost (in weed control, river cleaning, wildlife management, etc.) onto the State and resulting in the degradation of a valuable community resource.

The present state of affairs has been allowed to develop without any say ion the matter from those who suffer the most, the general public and the Royal National Park managers. It is only over the last two year and a half years that the voice of these people has been raised and considered on these issues.

If “Helensburgh” develops further, who is going to determine an “acceptable” degree of water quality and ensure that it is gained by proper planning, construction and control and who is going to share the associated costs of these necessary protective measures? This calculus is a basic but very difficult part of the process which should underlie all policy decisions upon developments in the area.

The Hacking River and certain tributaries can expect massive increases in volume of rainwater and associated waste discharge directed there from all sealed and street surfaces by gutters and street drains and from house and other roofs by pipes and man-made stormwater drains. Although in proportion to the water volume the quantity of waste matter may be small, it can and does have major detrimental impacts on the quality and amenity of the receiving water bodies out of all proportion to the relative quantity of this waste matter and this impact is generally accumulative. Little is known about these flows and even less action is taken in modern Sydney developments with few exceptions to control them. By their nature – being derived from rainfall across an area – they are extremely difficult to manage, Acquiring a special waste load through the scouring of man-made wastes from developed surfaces, the volume and directions of flow depend on the basic factors of city layout design road and building materials and human activities: they tie massive liquid waste flow intimately into town planning and development. No such control is planned in any of the new developments prepared for action now and likely to increase the population of Helensburgh fourfold and expand the developed urban area. Their lack of control will only vitiate other expensive management and control provisions.

It is to be expected, too, that urban development in the upper catchment area will also enhance stormwater intrusions of sewer mains with added disruption of the management system and rising incidence of sewer overflows.

The variability of the rainfall has another important bearing on sewer overflows. The rainfall over the upper catchment is highly variable and it suffers from frequent brief periods of relatively heavy rain on a small number of days. These heavy rain periods will almost certainly contribute to regular overflowing of the sewers.

It is interesting to note that when the sewer line from Helensburgh to Waterfall was constructed, the National Parks and Wildlife Service was given no say in the planning of the route of the line and the location of servicing points and sewer overflows, yet it was and will continue to be the Service which has and will bear the brunt of managing the problems associated with this lack of liaison and poor planning.

Sewer overflows particularly have been very poorly located with respect to environmental values and will significantly degrade the environment downslope of their location. Some have been located on natural ridge tops far from any natural watercourse to dilute and carry away the waste. It is expected that within a very short time these overflows will become weed ridden swamps.

The combined impact of the urban runoff and sewer overflows will be the constant accumulative degradation of the receiving waters affecting amenity, human and animal health and many natural values.

It is generally forgotten that many animals must drink the water in these creeks and animals are just as prone to the effects of toxins and pathogens as people. We can certainly expect animal populations which drink these waters to suffer periodic episodes of death and debility or enteric illness in proportion to the amount of waste entering the waters.

The chances of cataclysmic accidents occurring must also increase and these have been disastrous to animals downstream. All platypi and water rats Hydronomys chrysogaster were killed in Wilson’s Creek and the Hacking River in the mid 1970s as a result of a sulphuric acid spill on the Prince’s Highway in the headwaters of Wilson’s Creek.  Since then, no platypi have been seen anywhere in the Hacking River catchment area. What impact this acid spill had on other life forms is not documented or known.

In March of 1983 the National Parks and Wildlife Service was in the process of preparing a declaration concerning the possible health hazard to people from the waters of the Hacking River if they came into contact with or drank these waters. Fortunately, record rains and floods in the catchment area flushed the river out and lessened this threat. The major contributing factors to the problem were at the time, raw sewage and garbage tip leachate from Helensburgh Tip and Sanitary Depot and raw sewage from Garrawarra Hospital where in both instances, treatment processes had broken down and large quantities of raw liquid waste were released in the nearby creeks. It took over 18 months for the Helensburgh Sanitary Depot problems to be repaired despite great pressure from the National parks and Wildlife Service and the garbage tip leachate problems are still being “worked on”. The SPCC has been negotiating with the Health Department fro three years to repair the sewage treatment plant at Garrawarra Hospital and the National Parks and Wildlife Service is still waiting for a progress report on these negotiations.

These aforementioned polluting problems have had considerably detrimental and permanent impact upon the Hacking. Their impact was greatly exacerbated by other phenomena affecting the river at the same time, these being a record drought where the Hacking River stopped flowing on three occasions with, at these times, the only liquid entering the river being the wastes from the Helensburgh Tip and Sanitary Depot, Garrawarra Hospital Sanitary Depot Waste Water Treatment Plant, Metropolitan Colliery Waste Water Treatment Plant and Otford Valley Mushroom Farm. At the same time, the SRA Illawarra Railway Line electrification activities and the MWS&DB Helensburgh to Waterfall sewer works were contributing massive sediment loads to the creeks and river which silted up dramatically in places. In both of these instances the National parks and Wildlife Service had to battle for lengthy periods to gain control of these problems and eventually the SRA and the MWSDB had to employ Soil Conservation officers to prepare erosion control plans and direct restoration and control works.

However, the Hacking River ad many of its tributaries have been irreparably damaged as a result of this coincidental set of circumstances. Photographs of the Hacking River at Red Cedar Flat in Royal National Park in 1979 show a flowing clear stream over rapids and a mix of coal wash and sand banks. People were happily swimming in the river.  The banks were open and clear. Photographs of the same location in 1981/82 show the whole river bed to be a weed choked swamp with o water channel at all and the banks covered with a profuse growth of weeds. The bed of the river was stinking, putrid mud.

A monitor of the weeds since then has shown them to be spreading downstream at a rate of 4 kilometres per year. The inevitability is that they will infect the whole length of the Hacking River and even the shores of the Hacking Inlet.. These infestations will then become foci for the weeds to spread into the bushland surrounding. Coincidently, the Hacking River traverses the Park through the natural communities least able to resist this threat, the tall open forests and rainforests.

The coal waste dump in Camp Gully Creek for Metropolitan Colliery has regularly polluted the Hacking River with sediments and suspended particles. Black and grey sediments are spread the whole length of the river to Gray’s Point from its confluence with Camp Gully Creek. Many minor collapses of the coal dump walls have occurred blackening the bed and waters of the river for days on end. In the early 1970s a major collapse of one wall occurred and 10,000 cu m of coal waste was dumped into Camp Gully Creek to find its way into the Hacking River. The old walls of the dump have still to be stabilized properly and the Metropolitan Colliery is preparing plans for this now. However, in time, the coal dump must continue to erode and suffer periodic slumps of varying proportion. The walls are so steep that this will occur purely as a result of natural processes.

Recently, Metropolitan Colliery has constructed a 3½ million dollar waste treatment plant to treat all waters from their works (toilets, showers, cleaning yards, store depots, trucks, etc.). These have been a regular source of pollution. The treatment plant has reduced this pollution considerably but it has not removed nutrients from the waste.

Metropolitan Colliery has proposed the development of Stuart’s Gully south of Camp Gully Creek as the next site for a coal waste dump. Again, in the long term, such a dump must inevitably contribute back coal waste to the Hacking River.

This proposed dump is located in a most critical position in the middle of the wildlife corridor between Royal National Park and the forests east of Helensburgh and the Illawarra Escarpment. The use of this gully would seriously disrupt the potential for movement of species to and fro in this area and significantly contribute to the isolation of Royal National Park.

One can reasonably [predict that a result of further urban development of the upper catchment will be increased frequency and intensity of flooding downstream with their concomitant effects. The Audley Weir would be blocked on more occasions.


Another direct impact would result from increased predation upon wildlife from a large number of domestic dogs and cats living around the Park. Domestic dogs regulary hunt in Royal National Park either singularly, in small groups, or even in packs. They travel large distances on these forays. Many dogs from Sutherland have been caught at Garie Beach and Era.  They chase everything that moves and have even, although rarely, menaced people in the Park. Although not studied, I believe their hunting forays have made a significant contribution to the reduction in population numbers of many large mammals.

Domestic cats also make hunting forays in the Park from surrounding suburbs and may travel up to 6 kilometres into the Park in a night and return. Pygmy possums, classified as Endangered Fauna, are a prey species of the cat and many specimens have been deposited for show on floors and doorsteps around Heathcote put there by the household cat. Birds particularly are preyed upon.

Traffic through he Park would be expected to increase and an increased number of animal road kills would be expected as a result. Road kills are a significant cause of death in many animal populations in the Park. For example, in May 1982, 15 swamp wallabies, 7 possums, 3 bandicoots, 3 cats, 3 foxes, 35 birds (including lyre birds, kookaburras, owls, and wattlebirds), 4 snakes, 5 blue tongues, 1 wombat, 5 deer, 3 rats and 7 lizards were reported as killed on roads in the Park and this record is no where near a complete record for that month. The proportions would be different for each month as the different animals begin their various movements.

An increase in population around Helensburgh would lead to an increased visitation to the Park for recreation and place great demand on the recreation facilities which are frequently stretched to their full capacity now. Also these demands would be placed on a part of the park which is least designed for and has the least capacity for recreation and where recreational disruption to the natural environment would have the most impact – the tall open forest and rainforests of the Hacking River along Lady Wakehurst Drive, the route along which most of these new park users would enter the park.

Logging of the tall open forests and rainforest in and around Royal National Park has had a major impact upon these habitats. The rainforests in particular have been hard hit and their recovery has been seriously hindered by the incursions of fire, which have occurred more frequently and been able to enter the forests opened up by the logging. Deer particularly have hindered the recovery of these forests for a long time by grazing off the regenerating shoots, seedlings and saplings and considerably slowing down regeneration. The logging removed nearly all the big trees. A lot of clearance of ‘old and useless’ trees was done during this logging. Unfortunately it is these ‘old and useless trees’ which are most important for animals by providing the essential nesting and shelter hollows. Logging has consequently greatly reduced the carrying capacity of these forests for many animals (including birds) dependant upon hollows. It takes a forest a very long time to grow and mature enough for hollows to develop and the carrying capacity to increase again. The number of hollows in an area is in many cases the limiting factor for the population size of many species.

Dumping of rubbish and garden refuse in the Park can be expected to increase. The dumping of garden refuse is a particularly detrimental activity the full implications of which area poorly appreciated by the public. The spread of weeds and disease as a result can be very difficult and costly to control. The Park is regularly used for the disposal of garden refuse by some people. The impact of this sort of activity can be out of all proportion to the amount of waste deposited.



The further development of the Helensburgh area for rural, urban and industrial purposes would have a considerable detrimental impact upon conservation values in the area and upon Royal National Park.

To safeguard the natural values of Royal National Park, wildlife corridors must be established between it and the neighbouring natural lands units to mitigate against the fragmentation of the land into small natural units and to allow for movement of species between the land units to counter the effects of catastrophe and slow accumulative deleterious impacts.

Royal National Park requires some form of recognized and preferably reserved naturally vegetated continuity with the MWS&DB catchment lands to the west and sout west and with the lands east of Helensburgh, and the Illawarra Escarpment.

As much as possible the Service should seek to acquire these lands of seek their protection by special zoning.

The Service should be involved in all land-use planning design and policy formation within the catchment of the Hacking River.

R Crombie

Senior Ranger

South Metropolitan District

30th March 1984

Map 1: Hacking River Catchment

Map 2: Urban development areas acceptable to the Service (interim planning) – no urban development areas.

Map 3: Distribution of major vegetation =units in Royal National Park and southern wildlife corridors.

Map 4: Wildlife corridors connecting Royal National Park with Heathcote National Park, Woronora River Water Catchment Area and the Illawarra Escarpment.

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