Now, more than ever, people are valuing their accessible green spaces: neighbourhood parks, bush walks next to local creeks, and cycle tracks paralleling rivers. The quality of people’s experiences is, however, likely to vary widely depending on their local access to public spaces with nature. The liveability of our local neighbourhoods has never been more important, as more and more people use and connect with our public green spaces.

In the past decade, researchers and governments have become increasingly aware of the benefits of natural places in urban environments. Creating ‘green–blue urban grids’ across a city is thought to create more sustainable, people-friendly and climate-proof cities. Naturalising concrete waterway channels is one way to achieve such a grid.

We have worked hard in our cities in the past to funnel stormwater in the most efficient way away from urban areas to the coast. Concrete lining or channelisation of waterways has been employed in urban environments around the world for many years with the objective of efficient flood conveyance, stable channels, and maximising surrounding areas suitable for development.

Waterway naturalisation is the process of converting concrete water channels and underground pipes back to a more natural state to mimic, at least to some extent, the way they used to flow and function. This includes providing diversity in the structure of the waterway, slowing water down, revegetating, and creating habitat opportunities for flora and fauna. Yet while the benefits of naturalisation are becoming clearer, there are a still a number of hurdles that need to be overcome before the practice becomes widespread.

Alluvium’s team have been active over the past decade in advancing the policy, science, planning, and engineering of waterway naturalisation. More recently, this has included creating designs to maximise social and community benefits, along with ecological and flood management outcomes. In this article, we discuss what we see as some of the key emerging drivers of waterway naturalisation projects.

Alluvium has recently been engaged to help transform a 1.6 km section of concrete channel into a naturalised waterway with cycle and walking paths at Small Creek in Ipswich, west of Brisbane. Photo: Ipswich Council


Getting the policy context right

One of the more difficult barriers to overcome is legislative. Without the right policy settings, waterway naturalisation projects have proven to be hard to develop and fund. It is an expensive process to wind back the clock to pre-concrete days, despite the growing evidence of the social and environmental benefits that these projects generate.

Councils are often interested in channel naturalisation, but typically find projects difficult to get going in light of the legislative hurdles that need negotiating. For example, in some cases councils in NSW are required to deal with over 120 different pieces of state legislation, and there is not enough money to go around. It needs state government initiative, direction and leadership to help streamline the development projects. Channel naturalisation guidelines developed by state governments would also assist councils to facilitate decision-making around when, where and how to naturalise concrete channels.

Good design connects blue (water) and green (parks)

Good design is a critical element that helps harness community engagement with waterway naturalisation projects. Melbourne Water is one authority recognising the value of naturalising concreted waterways with their Reimagining Your Creek program. The program seeks to transform “storm water drains and creeks into waterways and desirable open spaces where people can interact with nature in cooler, healthier environments”.

One of Melbourne Water’s first major naturalisation projects within this program was reimagining 1.4 km of Arnolds Creek in Melton West. This  project included the involvement of Melton City Council, Western Water and DELWP towards the design development and financial contributions towards construction. The Reimagining program has an emphasis on community input and therefore included significant community engagement throughout the design process to inform the desired outcomes and design elements at the site.

Before being restored, this section of Arnolds Creek was long, straight channels with few environmental or social values.  Image: Drone still image courtesy of Melbourne Water .

Nearing completion, the Arnolds Creek naturalisation design brings people into the creek environment and will substantially improve the ecological values, recreation and social value to the community

The investment into the waterway health of Arnolds Creek delivers multiple benefits. Melton is one of the fastest growing towns in Victoria, and with a large proportion of the Melton workforce commuting outside of Melton for work, there is increased time pressure to be able to spend time in open space and engage in physical activity. The restoration of the waterway and creation of high-quality open space not only provides for improved ecological conditions, but also improves amenity of public open space, ultimately encouraging the community to use the space.

The complexity and multiplicity of stakeholders and institutions makes delivering collaborative projects a challenge, but key to the success of the Arnolds Creek project was empowering the community and allowing a participatory approach to decision making and planning, and doing this early on in the process.  This ultimately provided water authorities with the opportunity to improve their transparency and empower the community.

In the case of Arnolds Creek one of the bigger challenges was to design a space where people could safely connect with the creek to provide educational opportunities.  The final design incorporated stepping-stone designs that do not impede the hydraulic function of the waterway, are safe to approach and cross, drown out in larger flow events, and are an innovative landscaping feature that encourages interaction with nature.

Another good example of the benefits of good design is the Dandenong Creek naturalisation in Heathmont, undertaken as part of Melbourne Water’s Enhancing Our Dandenong Creek (EODC) program. The EODC program is an innovative and alternative approach to meeting sewerage containment obligations of the State Environment Protection Policy through investing in projects in the Middle Dandenong catchment which aim to improve amenity, reduce pollution, enhance biodiversity and encourage community engagement and education.

Construction of the Dandenong Creek naturalisation project.  Image: Courtesy of Melbourne Water

In the Dandenong creek project, the daylighting (bringing pipe flows to the surface) and restoration of the waterway not only provides for improved ecological conditions, but also improves amenity of a popular public open space, increases conveyance capacity of the waterway, and allows for broader community engagement.

Both projects highlight the importance of the community in the design and implementation process. In these cases, combining community involvement with champions and trusted experts to advocate and provide a credible voice to the process was critical to the success of the projects.

Meeting the engineering challenges of space, stability, aesthetics and community needs

Reconstructing natural waterways is no easy task, especially in cities with limited space and existing infrastructure such as sewer pipes, water pipes and electricity lines.

One of the means of naturalising a waterway is to slow down the water, and that takes up space. Think about the space required by a naturally meandering creek and compare that with a straight concrete channel. So often the design solution is to use smaller or meandering low flow channels within a larger channel.  The larger channel is where floodwaters can flow, while in the smaller channels we slow down the flow so water can more naturally meander from side to side.

Adding to engineering challenges, one of the major safety issues facing naturalisation projects is contaminated land. Decades ago, areas adjacent to waterways were often used as dumping grounds for waste. Contamination from waste adds a layer of complexity and cost to channel naturalisation projects.

To ensure the ongoing sustainability of naturalised waterways, engineering solutions need to look to the longer term. It takes a multi-disciplinary team to plan, design, construct and maintain naturalised waterways, all of which adds complexity to a project. As such, properly realising the benefits of a naturalisation project often requires large teams to support the planning, design and engineering. On a normal naturalisation project, design teams need all manner of engineers: civil, geotechnical and structural. On top of that, a project design needs input from landscape architects, social scientists, ecologists, soil scientists, and open-space planners as well as those that will maintain the waterway and surrounding open space once the project is complete.

The community is increasingly being vocal about, and incorporating, both Indigenous and post-European settlement cultural-heritage elements into naturalisation designs. In one example near the Chandler Highway in inner eastern Melbourne, designers shaped a wetland to be like an eagle’s eye because it is important in the storytelling of local traditional owners. In another, an 1850s bluestone wall was incorporated into the overall design to protect it and add aesthetic appeal.

Using channel naturalisation for patient recovery

Designing waterways as open spaces in and around healthcare facilities with the specific objective of improving the health of patients, staff and visitors to the facility is one area with significant potential for future projects. This means consulting health experts, which is a very different conversation than one with a council, water authority or the broader community.

Alluvium, REALM and Mosaic Insights were engaged by Melbourne Water in a project to naturalise a reach of Stony Creek in Melbourne’s west.  This project created an opportunity to incorporate design elements that responded to the rehabilitation and recovery needs of patients at Sunshine Hospital. Spaces in the project area were designed for patient consultations with some degree of privacy while being immersed in nature. Pathways in the area were designed with variable grades to cater for people at differing stages of recovery. Quiet areas were also created for contemplation and reflection, in close proximity to, but a world away from, the busy hospital.

Effective rehabilitation often involves exercise on surfaces that vary in grade and stability.  Image source: Amputee Coalition 

The aim of this work was to create an open space that improves the health of patients so key to this work was working closely with Sunshine Hospital staff from areas such as neurological rehabilitation, community-based rehabilitation and chronic pain.  These were very different conversations than the project team was used to.

The analysis and design approach blended elements of public health, landscape architecture and waterway engineering, and illustrates how understanding the specific requirements of the people who will use a naturalised waterway can be informative in waterway naturalisation design more broadly. The result is a more natural environment that supports mental and physical health, leading to a much greater wellbeing.

What is the next step for channel naturalisation?

As an industry we have become proficient in understanding the engineering requirements of channel naturalisation and working with ecologists to deliver benefits for flora and fauna. Although there is always room to improve, we are also getting much better at listening to the community and working through different design options to harness a wider range of social benefits generated by naturalisation projects. The next logical step is to consider how a more quantitative, evidence-based approach can help maximise those benefits.

Moving forward we think the approach to channel naturalisation can benefit from a rethink of the foundational principles behind design. Our traditional approach of developing initial engineering and landscape designs and engagement with the community to refine objectives and design elements perhaps should move to a more holistic framework based on the relationships between people and nature as the foundational blue print to start the conversation.

A good example of this is presented below as a proposed framework for studying benefits of nature contact. This diagram is adapted from Shanahan et al 2015 and illustrates a very different way to approach a channel naturalisation project, but will deliver a product well beyond a normal engineering led design.

Proposed framework for studying health benefits of nature contact

 We are excited about the next steps in channel naturalisation and how our work, and that of the broader industry, can explore in much more detail the relationships between design of green assets and maximising public heath outcomes.

For more information contact Jenny Butcher on 0438 835 292