Penrhyn Estuary

(Construction of Port Botany Expansion, insert pre-construction Penrhyn Spit)

(Construction of Port Botany Expansion, insert pre-construction Penrhyn Spit)

Penrhyn Estuary is located 9km south of the Sydney CBD on North Botany Bay, Lat. -33.96.  It is bounded by Foreshore Road to the north, Penrhyn Road to the east and the Patrick container terminal to the south. The Estuary was formed during the construction of Port Botany in the 1970s.


In October 2005 the NSW Minister for Planning approved the expansion of Port Botany and in so doing overruled the recommendations of the Government’s Commission of Inquiry(COI).  The Commissioner wrote in summary(2005:iv):

The Commission finds the proposed recreational and ecological enhancement works essential if Sydney Ports Corporation’s preferred option were to be approved.  If this were to be the case the Commission considers it likely the present ecological values of the Estuary could be substantially and permanently reduced due to declining water quality as well as the restricted access for shorebirds and the enclosing nature of the proposed Port expansion.

The Penrhyn Estuary Habitat Enhancement Plan(PEHEP) was mandated in Conditions of Consent under the NSW Environmental Planning and Assessment Act ( Section B2.31, B2.30)  and the Commonwealth Environmental Protection and Biodiversity Conservation Act.  Provision was made in the Conditions of Consent (B2.32) for an offset, under the EPA Draft Green Offsets(2002,) should the PEHEP prove unsuccessful.  The value established for 3.4 ha of bird habitat was put at $340,000, for 6.5 ha of Seagrass $900,000 and for 1.4 ha of Saltmarsh $980,000.


2003:  Shorebirds feeding at Penrhyn Spit

2003: Shorebirds feeding at Penrhyn Spit

Construction was undertaken by contractor Baulderstone – Jan de Nul Consortium.  Works, including the new terminal(T3), shorebird habitat and public amenities, commenced in May 2008 and concluded in June 2011.   In August 2012 Laing O’Rourke commenced work on behalf of the owners of the new terminal, Sydney International Container Terminals P/L(SICTL).   The  PEHEP, with a budget around $8million, included the removal of weeds such as Bitou (Chrysanthemoides monilifera subsp. rotundata) and Spike Rush (Juncus acutus)  as well as Grey Mangrove (Avicennia marina) (Sainty et al., 2012:492-502). Of the existing 1.4 ha of Saltmarsh 0.4 ha was removed for construction of T3 and 2.4 ha was created, including the planting of over 250,000 saltmarsh seedlings and cuttings, the largest recorded saltmarsh planting project (Sainty, 2012:494). Intertidal mud flats for shorebirds were increased  from 8 ha to 14 ha by removing sand dunes and adding fill.  Of a total of 9.7 ha of seagrass along Foreshore Beach 4 ha was approved for removal including TSC listed Strapweed (Posidonia australis). However prior to construction in 2008 it was reported that the amount of seagrass had declined significantly.  As part of the works 6.5ha of seagrass habitat is to be created.  Ancillary works include a public lookout and bird hide and there is a stated commitment to long term maintenance and monitoring mandated under the EPBC Act.

Stakeholder Involvement

Key stakeholders identified by Sydney Ports Corporation(SPC) during consultation for the Environmental Impact Statement(EIS) included residents and businesses in Randwick and Botany Bay municipalities as well as local and regional environmental groups and recreational users (Sydney Ports EIS).  The principal environmental groups were Save Botany Beach, Botany Environment Watch and the Botany Bay and Catchment Alliance.  Special interest groups included the Australian National Sportsfishing Association(ANSA) and The Australasian Wader Studies Group(AWSG).  The PEHEP  outlined in the Minister’s Conditions of Consent was a proposal supported by members of the AWSG.  The ANSA proposed major Boat Ramp facilities.  Neither organisation opposed the port expansion at the 2004-2005 COI hearings. As part of the Conditions of Consent (Section B3.2) a Community Consultative Committee(PBECCC) which included a Botany Bay Council representative and Community members was established in 2006. Consultation on the PEHEP included the PBECC, Randwick and Botany Bay Councils, Southern Regional Organisation of Councils(SSROC), Orica P/L, the DEH and NSW Government Departments: NSW Maritime, DPI, Department of Planning, Department of Natural Resources, DECC. One public Open Day was held in November 2006.


2002:  Saltmarsh and Mangrove around Springvale Drain

2002: Saltmarsh and Mangrove around Springvale Drain

SPC and representatives of the AWSG argue that this is an ‘enhancement’ project while others note the lost opportunity to provide enhancement of what existed.  In written and verbal communications SPC staff consistently referred to Penrhyn Estuary as the corporation’s creation implying that the habitat for shorebirds was therefore of lesser value.  In the plan produced by SPC in late 2001 and exhibited at consultation meetings the Estuary was shown as part of the reclamation for T3.  The development-driven approach taken by SPC during this period was similar to the Port of Melbourne’s approach to the dredging of Port Phillip Bay with the Australian Ports community attitude to priorities and process captured in a submission to the Commonwealth’s Inquiry into Australia’s National Parks, Conservation Reserves and Marine Protected Areas. (2006)

Obligations under the EPBC Act  and international treaties JAMBA, CAMBA and ROKAMBA became the key driver for the project.  SPC made a referral to the EPBC in January 2002 and the DEH determined the project a controlled action under provisions  for listed migratory shorebird species(EPBC Sections 20 and 20A) and Wetlands of International importance (EPBC Sections 16 and 17B).  Consultation during 2002 and 2003 was conducted with a range of individuals and groups including specialist shorebird groups.  The spokesperson for the main shorebird group, AWSG, was engaged as a consultant for SPC (see 2003 EIS 5.2.3). His rationale (pers. comm. 2004) was that there was no stopping the development and this presented an opportunity to enhance habitat for migratory species.  Overseas examples were cited.  Some in the Shorebird Observers community disagreed.  Based on scientific studies there were arguments made for stemming the decline of saltmarsh habitat in Botany Bay.

While the  project  cost SPC around $8million, arguably the return has been higher.  Apart from publicity in 2011 for awards achieved  the promise of a purpose built boat ramp for fishers and particularly the PEHEP  served to divide opposition against the T3 development and distract attention from flaws in transport modelling.

Project Objectives

The area is low lying.  Prior to recent construction works there were sand dunes 2.5 to 3 metres high and estuarine habitats included saltmarsh, mangroves, intertidal mud and sand flats, and seagrass. Mangrove intrusion into saltmarsh is a recognised problem. As part of the PEHEP removal was recommended to improve shorebird habitat.  The mudflats have provided the most productive feeding habitat for migratory shorebirds.  Floodvale Drain from the north-west and Springvale Drain from the north east as well as groundwater from the Botany Aquifer discharge into the area. The drains carry shallow groundwater to the Estuary as well as stormwater during rainfall.

The following objectives of the PEHEP  have been clearly and consistently expressed:

  • expand the existing shorebird habitat, to continue to attract migratory shorebirds and potentially attract more shorebirds;
  • create seagrass habitat;
  • expand the area of saltmarsh habitat; and
  • provide controlled public access and minimise disturbances within the Estuary.

These are mandated upfront rather than reflecting the needs of the project as it developed. Offset conditions have provided another dimension to the objectives as there could be incentive to deem the project a failure before critical processes have established.

The embayment is inundated at high tide with water covering an area of approximately 4.0 ha. At low tide, mudflats are exposed and the inundated area is approximately 0.4 ha. It was originally devoid of vegetation when formed in the late 1970s using sandy dredge spoil from development of the adjacent port.  The inner estuary discharges to the outer estuary which discharges to Botany Bay. A typical salinity gradient exists in the estuary, from the fresh discharge in the upper reaches, to the saline inflow from Botany Bay.  The estuary has been polluted with heavy metals and chlorinated hydrocarbons by local heavy industry. As part of the Botany Groundwater Cleanup Project contaminated groundwater is intercepted via a line of bores along Foreshore Road.


The PEHEP was managed along with major construction works by Baulderstone however there are examples where integration has not been achieved. At the Port Botany Expansion Community Consultative Committee (PBECCC) held in September 2012 SICTL reported that relocation of some saltmarsh will be required and this will be done with existing contractor.  In their September report reference is made to the removal of .7 ha of saltmarsh to other areas of the estuary to allow for stormwater works which were not planned as part of the main construction works.  Questions were raised at the Port Botany Neighbourhood Liaison Group (PBNLG) in November regarding net loss and approval provided by DPI(Fisheries). The area of saltmarsh removed represents 30% of the creation section of the project and 20% of the total and yet this has occurred with minimal scrutiny and without reported reference to other processes under development.   While it is recognised that some elements require a longer timeframe before final assessment, the PEHEP does not detail complex interactions.  For example no targets have been set for benthos biomass  and it is not covered in the Contingency Plans (PEHEP Section 7).   The project could be declared a failure if shorebird numbers continued to decline when, for example, an extension to the timeframe to allow benthos mass to build to a critical level might be required.


1 January 2013: Mudflats; Big Island; Government Pier

1 January 2013: Mudflats; Big Island; Government Pier

The PEHEP was developed to provide a cohesive plan to address approval conditions set by DEH and DECC.  The  Penrhyn Estuary Concept Plan  was provided to government agencies DEH, DPI(F), DOP, DNR,  DECC, Botany Bay and Randwick Councils and they provided feedback on the general concept, as well as monitoring of benthos, sediment, seagrass, saltmarsh, birds and water quality, and management of marine mammals and vegetation.  This was incorporated into the draft PEHEP which was placed on public exhibition. Not all issues were addressed particularly if they related to matters which were considered by SPC to be not directly related to the expansion.  A further problem concerned the feedback from government agencies.  This was provided individually rather than cooperatively.  For example DPI(Fisheries) focussed on seagrasses but there were no comments relating this element to overall objectives.  A forum of government stakeholders would have been useful to focus all parties on objectives.  Staging, success criteria and contingency plans were outlined in the PEHEP.

Performance Standards

Performance standards are defined but the level of monitoring has varied.  For example the SPC website contained pre-construction, construction and post-construction reports yet for water quality there were no reports published until 2013.  While there are pre and post reports for seagrass these are sketchy. The PBECC received monthly updates on the PEHEP but as one member of the committee commented: on the rare occasions that an inspection of the sea grasses was possible the reports always reflected a conclusion to the effect that the incidence of the 3 main seagrasses ( Zostera, Posidonia and Halophila) were always less than 5% of coverage in the 10 monitoring stations. In many locations there was no evidence of seagrass. Quite obviously the poor water quality and lack of sunlight due to suspended matter in the water column was not conducive to seagrass life (personal communication 17/12/2012).

Developing easily observable measures of success is a key process in restoration but in the PEHEP the indicators require tighter definition with greater emphasis on contingency measures and intervention from key authorities as this observation from a PBECC committee member attests:  Now that SPC is contemplating the construction of 3 extra groynes along Foreshore beach to mitigate wave energy and stop the beach erosion it will be interesting to see what impact this will have on stabilising the sea grass beds and whether or not new weed life can be rejuvenated. I am hopeful but not confident. I have also given my colleagues ( now ex colleagues) at Cronulla Fisheries a number of serves over their continued failure to do anything about the plight of the sea grasses on this side of the Bay (personal communication 18/12/12)

The key element of the PEHEP is the continued and ultimately increased uptake by shorebirds.  However success, as it relates to the Offset provisions of the Conditions of Consent, is predicated on all elements being met.  While the health of saltmarsh and mudflats is critical to targeted shorebird species, seagrass is less so.  The emphasis has been on shorebird uptake but the defining process is the flushing of the estuary.  If adequate flushing is not achieved when T3 is fully operational then the estuary could become a gross pollutant trap as suggested by the Commissioner(2005).

Strategies for long-term protection and maintenance

Long-term protection and maintenance is mandated under the EBPC conditions.  SPC are required to ensure that an independent audit of compliance is undertaken every five years from the date of completion of the project.  The first report is due in June 2016.

It is critical to note that if, despite implementation of contingencies and ongoing monitoring, success criteria are not likely to be achieved, Sydney Ports will implement an offset package in accordance with Condition B2.32 of the Department of Planning consent, 13 October 2005.  This will be triggered if the ‘no impact criteria’ for any one of the three key habitat elements, namely shorebird usage, saltmarsh and seagrass coverage, are not met. The Offset is estimated around $2.22 million.   If SPC are required to pay for an Offset they would not be obliged to continue maintenance and monitoring of the estuary.  Were the shorebirds to cease using the area or if it were deemed in their best interests to be discouraged as has previously occurred on Ports land with advice from National Parks (see NPWS Little Terns Recovery Plan), then for a relatively small price SPC could be in a position to develop the area, around 27ha, for container shipping.  This was their preferred option in 2001.

The PEHEP area is isolated from the main public areas with the bird observation section 800 metres from the main public facilities.  On concept plans on exhibition prior to approval of the Port in 2005  the public beach extended to Floodvale Drain.  However, the Estuary Concept Plan and later the PEHEP included the area adjacent Floodvale as saltmarsh and the area to the west of the bird observation lookout as rocky foreshore.  The PEHEP was approved in early 2007 but in the Contracts Summary of December 2007 the beach  marked as saltmarsh in the PEHEP is recorded as beach access.  The area to the west is rocky foreshore.  In the final design there is no public access beyond the highly eroded area near the outlet from Mill Pond adjacent Sydney Airport’s Third Runway.  The loss of Botany’s beach was a contentious local issue. Comments were made that there was more concern for the birds than the humans (PBECCC Meeting 8).  Popular species of birds that were previously prominent, such as the Pelican(Pelecanus conspicillatus), were declared ‘bird hazard’ and measures taken to discourage them from T3 and surrounds.  Little Terns protected under the TSC Act and known to roost in the area were not a targeted species and therefore not accommodated in the habitat plan.  They have been discouraged with a view to concentrating them at Towra Point on the southern shores of Botany Bay. This is supported by NPWS  despite significant fox predation, erosion and human disturbance issues.  There are restoration ecologists who argue the importance of a broadened ecological view and a more urgent emphasis to attract substantial and ongoing support of mainstream society.   SPC have not adopted such an approach and the PEHEP stands in contrast to the Freshwater Creek Wetlands project which is located in the same catchment, of similar cost and funded by a State Government corporation.  The difference however for Freshwater Creek, Chullora, was the involvement of volunteer community groups. While the Chullora Project will continue to enjoy support from local community volunteers, there is no similar structure to support Penrhyn.  This has been a top down project with the main protagonist for shorebird habitat also engaged as a paid consultant.  There is unlikely to be strong opposition if an offset arrangement is required as identified  offset sites are already supported by ASWG members.  Access to the Bird Hide at Penrhyn is restricted to daylight hours and on occasions even during daylight has not been opened.  Basic public facilities are located 800 metres from the site.


The greatest strength of the project has been the saltmarsh program. Survival rates have been high, three major species have established, Spiny Rush (Juncus acutus) has been controlled and there is no evidence of mangrove intrusion.   This success has also been effectively promoted(Sainty et al., 2012:494-502).  The area is tidier and the bird observation lookout as a new facility has aesthetic and practical benefit.  However key elements lack integration because the SPC approach is primarily driven by a compliance regime and government agencies have not developed a coordinated focus.  This is a shorebird habitat enhancement but targets on benthos have not been established.  Seagrass targets don’t relate directly to shorebird habitat.  In all documents produced by SPC staff and consultants reference has been made to the degraded state of the pre-construction estuary. There was no mention of simple measures to enhance values and afford greater protection to shorebirds from predators and human disturbance.  In September 2003 a Clean Up Notice was served on Orica P/L for what was reportedly the largest chemical spill in Australia.  This spill included Orica contaminated groundwater and surface water flowing into the estuary.  In late 2004 a fishing ban was issued by the DPI(Fisheries).  No suggestion was made that as part of the Clean Up Orica might be held responsible for a cleanup of Penrhyn Estuary. In its submission to the COI Orica supported the SPC development and argued that the development would have no detrimental effect on the functioning of the estuary and Orica’s attempts to achieve containment of the contamination. By contrast the consulting hydrologist on the Orica Independent Monitoring Panel during a presentation at an Orica meeting in late 2006 said that Penrhyn Estuary would ‘cease’ as a result of the expansion.  URS Australia managed the production of EISs for both the SPC expansion and the Orica 2004 Groundwater Treatment Plant.  Two members of AWSG acting as consultants for SPC appeared at the COI in support of the development and the representative from Ecology Lab went as far as to state that Estuary ecological values would decline further if the SPC development were not approved. (COI 2005 report A4-1).

Despite various parties, including the Commissioner,  arguing that the development of T3 would have a detrimental effect on the functioning of Penrhyn Estuary the development was approved and the PEHEP  effected. While saltmarsh enhancement is proving successful the uptake by targeted shorebird species has been disappointing. At the August 2015 PBCC the representative from the Port Authority of NSW (formerly Sydney Ports Corporation) reported:

Of the six target species, targets for five of the six have not been met.

Post construction numbers compared to pre-construction for targeted species are significantly lower except for one, the Pacific Golden Plover (Pluvialis fulva) where higher numbers have also been reported at the reference site.  Reports also note significant wind erosion on Big Island, created for roosting, and fox predation as a threat during low tide. Since the completion of construction in June 2011 there has been a T3 design modification proposed and approved by DPI to allow for a significant increase in building heights.  The Department was initially concerned that the increased height of buildings on the terminal may have an impact on bird flight paths  but was assured by the avian and wetlands specialist consulting to SPC that this would not be the case. Despite their concerns and the importance of unimpeded access for shorebirds to the site the DPI did not commission an independent report.  When the draft PEHEP was on exhibition distribution was restricted because SPC refused to provide website access and it was left to a volunteer group to facilitate.   In a letter to SPC around the same time Randwick City Council recommended involving the community in on-ground works  but this was rejected.  The lack of local community involvement has been a major failing.  There has been publicity on the SPC website and in the form of advertorials and advertisements in the local newspapers but no direct involvement.  Apart from an Open Day to elicit comments on the draft PEHE there has been no follow up engagement.  Regular briefings of the PBECCC have occurred but membership of that forum was restricted.  In an early evaluation of the effectiveness of the committee a comment was recorded that most groups who are informed chose not to be part of group (SPC, 2006 Presentation to Meeting 8, January 2008).  Given the importance of the saltmarsh component of the project and the design of buildings on T3 to achieving project objectives for shorebird uptake it is significant that there are no comments recorded in the PBECC minutes on saltmarsh removal and height increases.

A number of residual risks and contingency measures have been identified in the PEHEP.  These need to be evaluated leading up to first major audit in 2016 required under the EPBC Act.

The COI Commissioner, and others, suggested that water quality would decline with the construction of T3.  The DEH in the Variation of Conditions of Approval 2006 added flushing of Penrhyn Estuary to the list of conditions ) after the fifth berth was approvedin 2006.    Finlay and Gillespie noted that SPC consultants anticipated that flushing of the estuary would reduce from 0.7 days to 2.7 days with the preferred SPC configuration of T3.  In the first website published water quality report by Sydney Ports Turbidity readings exceeded ANZECC guidelines in 28 of the 34 samples.   Testing for heavy metals and contaminants has occurred and in a report to Meeting 6 of the PBECCC 5 of the 12 mercury exceedences were reported from the estuary.  The presence of heavy metals along with chlorinated hydrocarbons has led some to suggest that it might be irresponsible to encourage wildlife to this area.   Further research is required on the effects of reduced flushing on water quality, sediments and benthos. There is also scope for joint research between Australia and flyway partners on contamination levels in priority species  such as Red-necked Stints (Calidris ruficollis). Kim and Koo in research on contamination in Stints,Great Knots(Calidris tenuirostris) and Terek Sandpipers (Xenus cinereus) at Okgu Mudflat, Korea, concluded that the elevated concentrations reflected their breeding or wintering ground concentrations and not the study site.   Initial work on chlorinated hydrocarbons in Penrhyn has been conducted but there has been no research on avian health.  Additional monitoring for chlorinated hydrocarbons as suggested by the Orica CLC expert hydrologist, Professor Ian Acworth, but previously rejected by Orica and SPC could be undertaken.  Research into phytoremediation capacity of the three key saltmarsh species present is also suggested.  Work has been done in the nearby Cooks River on mangroves  and there are international examples for saltmarsh.  Although the PEHEP does make reference to accommodating changes in environmental conditions such as sea level rise, further research is required in modelling sea level rises and the predicted increase in storm surges.