Sydney Park Water Re-use Project

Challenge

• Capture, clean, and re-use stormwater from the Munni Catchment north of the park in support of the City of Sydney’s goal of reducing reliance on potable water by 30% by 2030.This includes providing a sustainable water supply to the park and increasing storage capacity of previously existing wetlands.
• Improve water quality by redesigning and re-engineering the circulation of water through the chain of constructed wetlands.
• Increase habitat and species diversity in order to improve overall resilience of the ecosystems in the park.
• Increase opportunities for physical activity, attract more visitors to the park, and enhance public enjoyment of the park.
• Improve connectivity and circulation with modifications to the existing Sydney Park path system and the addition of bridges, stepping stones, lookouts, and seating.
• Infuse the wetlands and the park with a high-quality visual experience which expresses the “water story” and promotes opportunities for lifelong learning.
• Enhance the park’s sense of place and character for nearby neighbourhoods by showcasing freshwater wetlands and their management as central to the park’s visually pleasing setting.

• The main feature of the project is a stormwater treatment system designed to harvest as much as 850 million litres (approximately 225 million gallons) of stormwater per year from the Munni Catchment just north of the park. The system was designed to divert water from the Munni Channel, an open concrete storm drain that runs through the northeast corner of the park, into a previously existing system of 4 constructed wetland ponds in Sydney Park.
• Using an underground pipe, low stormwater flow is pumped into a vegetated swale and then diverted onward to a small wetland where it is polished and discharged into the larger system of wetlands. Larger storm flows are treated by a gross pollutant trap in the park before being directed through wetlands 2 and 4 where water is filtered and cleansed. From the low point of the park in wetland 5 (there is no wetland 3), the cleansed water either overflows into the urban stormwater system or is pumped into the reuse system in the park, depending on conditions. This reuse system further treats the water by filtering and polishing it before pumping it to wetland 1, near the high point of the park, where some of the water is recirculated through the park for reuse for irrigation and non-potable services. The balance of water is returned to wetland 2, where it flows again through the system of wetlands.
• In 2017 the new stormwater treatment plant on-site had to be relocated to accommodate construction of a motorway. It is scheduled to re-open in late 2020. In spite of this disruption, currently 114 million litres (approximately 30 million gallons) of recycled water is harvested per year for improved circulation of the ponds, irrigation, and non-potable water supply.
• A bioretention system consisting of 4 cells is integrated into the perimeter of wetlands 1, 2, and 4. The bioretention system includes 4,500 square metres (48,440 sf) planted with 150 indigenous plant species including common rush (Juncus usitatus), hop goodenia (Goodenia ovata), knotted club rush (Ficinia nodosa), and soft twigged sedge (Baumea rubiginosa). The bioretention cells are supported by gabion walls, and a series of gabion-clad weirs and subsurface pipes control overflow incidents throughout the bioretention system.
• Microhabitats are integrated into the edges of the bioretention system including lizard lounges, frog ponds, and a variety of nesting boxes for birds and possums.
• A series of 5 gabion-clad retaining walls known as “The Cascades” aerate water as it moves between wetlands 1 and 2. Bridges and broad, flat stepping-stones within an enclosed forest area known as “The Gully” allow visitors to traverse “The Cascades” at various points. Small terraces and benches within “The Cascades” allow for scenic viewing. “The Gully” supports 178% increase in native gully forest species, from 32 to 89. 
• A corten and brick aqueduct with split flows delivers stormwater into the bioretention cell on the northeast perimeter of wetland 2. A gabion-clad spillway and a newly-constructed creek control the flow of water between wetland 2 into wetland 4.
• “Water Falls”, an environmental artwork consisting of sets of raised terracotta channels, returns cleansed water to wetlands 1, 2, and 4. The raised channels create habitat.
• A hierarchy of paths, lookouts, boardwalks, bridges, stepping stones, platforms, lighting fixtures, and seating areas provide visitors with diverse opportunities to interact with the wetlands.
• Materials that reference the layered history of the park include the terracotta pipes used in “Water Falls”, the corten steel and brick aqueduct, the gabion walls, and the recycled brick edging some of the paths.

Brief History
The Cadigal, the local Aboriginal people, used the clay in the shale-based soil in the area of St Peters (the area in which Sydney Park is located) for ceremonial purposes, for healing, and to seal canoes. From the early 1800s, Europeans excavated the deep layers of high-quality shale for brickmaking and transformed St Peters into one of the largest concentrated areas of brickmaking activity in Sydney. At the peak of brick production, the site that Sydney Park now occupies comprised seven clay pits and five brick manufacturers. By the mid twentieth century, the shale was depleted, leaving a series of large, deep pits. From 1948 until the early 1980s the City of Sydney used the site as a landfill; in 1979 the New South Wales Department of Planning designated the site as one of several depleted industrial sites to be converted into parks. Since the official opening of Sydney Park in 1991 the wetland components of the park have evolved through a series of small projects.

Planning Context
The Sydney Park Water Re-use Project was initiated by a series of connected events and policies: the Millennium Drought, the Detailed Master Plan for Sydney Park (2006, Aspect Studio), Sydney 2030 (City of Sydney’s 2006 strategic plan), the City of Sydney’s Decentralised Water Master Plan (DWMP), and Federal government support. It is the second phase of a stormwater harvesting project for Sydney Park; the first was implemented in 2010-2011 and was much smaller in scale. The second phase, the Sydney Park Water Re-use Project, was the first major project to be realised from the DWMP; it is also significant as one of two precinct-scale projects in the DWMP. The second is Green Square, a large urban infill project. As of 2020, an extension of the M5 motorway is under construction along the south and east edges of Sydney Park.

The art installations and water features offer environmental and social value for Sydney Park users at a nominal construction cost, with the art installation of water cascades, stepping stones, and pipes adding only $6 AUD (appx. $4.21 USD) per sf to the overall cost of the project. The overall cost of the project including the art installation was $11 million AUD (appx. $7.7 million USD), and without the art installation the cost would have been $10 million AUD (appx. $7 million USD). The art installation cost was 8.9% of the overall project and 12.6 % of the landscape and amenity cost of the project.

• Initiated in 2012, the realization of the drought-proofing goals of the Sydney Park Water Reuse Project involved an iterative process of review and monitoring. This process has generated additional projects, most notably the relocation of the water treatment plant, the central component of the project. After the original plant was decommissioned in 2016 due to the construction of the M5 Motorway around the south and eastern perimeter of the park, the City of Sydney commissioned a new treatment plant. Opened in October 2020, the new plant has improved the capacity of the park to meet its water demands by pumping, treating, and storing 25 megalitres (approximately 6.6 million gallons) of water onsite, and it has the ability to expand to 75 megalitres (approximately 19.8 million gallons) of capacity. The recycled water from Sydney Park is now used within the park for irrigation and non-potable services, as well as across the city to clean streets; water trees; and irrigate the city’s network of parks, street gardens, and floral installations.
• The integration of environmental art into a green infrastructure projects adds social and ecological value at a reasonable cost. “Water Falls” has enhanced the experiential qualities and educational value of the Sydney Park wetlands system. The lesson here is the value-add of a design proposal/return brief to the client which enhances the initial design vision. In this project, the design team identified and advocated for the inclusion of environmental art in their return brief and made the case for extra funding to support it.
• Climate resilience initiatives such as the Sydney Park Water Reuse Project have the potential to generate a range of social and ecological benefits. The “thick” edges of the wetlands have enhanced biodiversity as well as the experiential qualities of Sydney Park by integrating views, pathways, sounds, textures, and physical challenges.
• The Sydney Park Water Reuse Project benefited from the involvement of a large and diverse team led by landscape architects. Over the life of the project, the team expanded to integrate and leverage the expertise of a range of stakeholders including designers, asset managers, and contract managers as well as urban ecologists, water engineers, and environmental artists.

Soil: Australian Native Landscape
Planting supply: Andreasens Green and Toolijooa
Waste capping layer for planting area: Clay +HDPE liner
Concrete pathway: Metro mix Terralba aggregate
Deco granite: Australian Native Landscapes
Recycled brick banding pavement: City Brick Recycler, St Peters, Sydney
Tactile ground surface indicator: DTAC, Stainless Classic
Habitat PVC coated chain wire fence and gate: Protective Fencing
Gabion wall (supplier): Permathene
Gabion wall (installer): Collective Civil
Bifurcated aqueduct fabrication: Stainform
Balustrade and handrail fabrication: Stainform
Habitat elements, logs, rocks: Contractor
GRP Boardwalk structure and bridge: Partridge Engineering Structural Design; Stainform Fabricators
Terracotta artwork - “Water Falls” (fabrication and installation): Wardrope and Carroll Engineering 
Bollards: Leda Securities slimline bollard
Lighting: Luminaire GE Lighting; Evolve LED Post Top Twin Contemporary Tiered Circular
Precast concrete bench seat: Sydney Precast PTY LTD
Recycled timber bench seat: Street furniture, Australia Classic Plaza Seat
Tables: Street Furniture Australia, Classic Plaza Table
Drinking fountain: Hawsco / Moodie Products, Hawes Accessible Drinking Fountain
Rubbish bin: Emerdyn Oxford WBE 120L
Bike hoops: Leda securities Hoop Bike Rail
Signage: City of Sydney Council

Project Team

Landscape Architect: Turf Design Studio and Environmental Partnership
Public Artists: Turpin + Crawford Studio 
Ecologist: Dragonfly Environmental
Environmental Management: A.D. Envirotech Australia
Irrigation: Hydroplan
Lead Contractor: Design Landscapes
Lighting and Electrical: Lighting Art and Science 
Water Experts: Alluvium and Equatica
Soil Investigation: SESL Australia
Structural Engineer: Partridge, Arup

Role of the Landscape Architect

The team of landscape architects were the project lead. Their role was to design and document the stormwater harvesting system, inclusive of associated landscape elements. They organised and collaborated with civil engineers, artists, ecologists, soil scientists, landscape contractors, lighting experts, and the City of Sydney’s landscape architects to develop the design of the project and oversee construction.