River Pods

There was no client as such as the ‘River Pods’ concept was a speculative exploration of Neil’s own doing to find opportunities to engage with our river and to improve the health of the river system.

The following information has been sourced from the ‘Marli River Park document – An Interpretation Plan. Swan River Trust – 2014’ - Noongar cultural ideologies, language and social mores have been based on the same tenets since kura kura, a long time ago and are transmitted and maintained via stories. While the content of these stories may change in accordance with the narrator, location and audience, the Waakal (Waugal, Wagyl, Waugyl, Wagul etc.) or Noongar Rainbow Serpent is commonly depicted as the creator.46 Many Noongar consider the Swan-

Canning Riverscape sacred due to stories associated with the Waakal and its continued presence in the area. Noongar Elder Everett Kickett theorised that the Waakal created the Derbal Yiragan, which means where the estuary is filled up by the winding river, now known as the Swan River.

Furthermore, Noongar Elder Ralph Winmar wrote that the Waakal made all ‘rivers, swamps, lakes and waterholes’. If one were to look at Derbal Yiragan (as the Perth waters of the Swan River) from the top of Kaart Djinanginy Bo, or Mount Eliza (Kings Park), it would be easy to visualise this huge Waakal twisting and turning as it made its way to the coast. Noongar Elder Albert Corunna said, during the Dreamtime the Waakal ‘moved across the landscapes of Perth and as he moved the waterways were created which included the Swan River’. He explained, ‘(t)his is the way the rivers were made as told by my old people'. (Source: Marli River Park).

The Dutch mapped the Swan River in 1697 but did not explore the Canning. The first Europeans to report seeing the Canning River were the French in June 1801. A party from Nicholas Baudin’s Naturaliste led by Heirisson first explored the Swan,

encountering difficulty at the ‘flats’ which they named Heirisson Islands. They then turned their attention to the Canning River entrance they called Entrée Moreau, after a member of their party, midshipman Moreau. They did not explore further but

commented that it probably linked with the sea. The first Europeans to explore the Canning River, so named by Captain Stirling, was a small team from the party on their return from the journey along the Swan in 1827. 

Lyon’s 1833 map of Aboriginal groups around Perth has the Canning River as Munday’s Beelo territory on the north of the river with Midgegooroo’s Beeliar territory to the south. These groups feature prominently in the early European exploration and settlement of the Canning River. 

The river provided rich resources for the various groups as they travelled through and camped in the area. Early European explorers noted a widespread Aboriginal presence and relationships were relatively friendly. The waters of the Canning provided rich resources for the Noongar people in the area and the banks provided materials for everyday life. The area was one of significant activity for Aboriginal people with intense movement along the riverside tracks and across the landscape.

The Swan River Trust engaged with a consultant team, the National Trust a Noongar advisory Panel along with other esteemed contributors to create a vision for the Swan River and its surrounds. This final document is a fabulous source of information and considers so many aspects of the rivers history and physical make up as it proposes that in its entirety the precincts of the Swan River and Canning River would be known as the Marli River Park. The creation of marli riverpark is the major guiding and transformative initiative of the Interpretation Plan. marli, marlee, maali, marley is the Noongar for Swan (Cygnus atratus), The name 'marli' signals significance above, below, in and on the riverscape. The use of lower case 'marli' signals ‘not’ using the English conventions and grammar. We do not speak or listen in capitals hence marli signals a spoken and audio [listen] communication, not a written one.

‘The river’ by Jennifer Kornberger, 2013

This river once had a mouth that opened and closed.

A mouth with limestone teeth and a tongue of sand.

The first rains woke it from its estuarine sleep, loosened its tongue, so the mixing, the darbaling could begin.

When rainbows became scarce the river sealed its mouth, it curled back and listened

to the thousand voices informing it.

A river lives between course and discourse. It has business, the office of its whole catchment to fulfil.’

There is a history of bathing in the swan river with opportunities for formalised bathing previously available at the Claremont Baths, Matilda Bay Baths, and Perth City Baths. With all of these bathing pavilions now long gone, this concept for the ‘River Pods’ provides opportunity for safe bathing in the river once again.

The geology of the Swan Coastal Plain consists of deep layers of sediments and sedimentary rocks dating back to the Cretaceous Period, 146-65 million years ago.

The youngest of these, from the Quaternary Period (2.6 million years to the present), are intersected by the Swan and Canning River systems and are visible along the riverbanks and estuary foreshores. Interestingly, this period also saw the evolution of the human race and the eventual habitation of the Coastal Plain by Aboriginal people. The Quaternary is described as “characterized by a series of large-scale environmental changes that have profoundly affected and shaped both landscapes and life on Earth”, with an estimated 30-50 glacial cycles occurring.70 Over 40,000 years, Aboriginal people saw the effects of at least one glacial cycle with the rising and falling sea levels and warming and cooling climates which resulted in the Swan and Canning systems as they existed at the time of European settlement.

Around 20,000 years ago, sea level was about 130m below today’s level, Rottnest was just a hill, and the Swan River met the ocean somewhere to the north-west of that hill. By 7,000 years ago, Rottnest was still connected to the mainland, but only just. Sea levels peaked around 5,000 years ago and have since fallen a few metres to the current level. The former Swan and Canning River valleys have been largely flooded by the ocean and filled with sandy and muddy sediments to become the Swan Canning Estuary. 

The Swan and Canning Rivers support a diverse array of plant and animal life. There are over 130 species of fish that utilise the estuary including herring, cobbler, mullet, black bream, whiting, crustaceans (including two species of prawns), bottlenose dolphins, long-necked turtles, frogs, seahorses and at least two species of jellyfish. Birds include waterbirds dependent on wetlands for feeding, resting and breeding as well as those migratory species that visit each year. The most well known birds on the rivers are black swans, four species of cormorants, herons, darters, pelicans, ducks, ibises and egret.

The black swan/marli is now the symbol of the Swan River. Dutch explorer Willem de Vlamingh surveyed and named the river Swarte Swaene-Revier in 1696 when his exploration party saw many of the birds. In reporting on his journey up the Swan

River with Captain Stirling in 1827, botanist Charles Fraser described in some detail the abundant bird life around Point Fraser and the sustenance it provided: The quantity of black swans, ducks, pelicans and aquatic birds seen on the river was truly astonishing.

Without any exaggeration, I have seen a number of black swans, which could not be estimated at less than five hundred rise at once, exhibiting a spectacle which,

if the size and colour of the bird be taken into account, and the noise and rushing occasioned by the flapping of their wings, previous to their rising, is quite unique in

its kind. We frequently had from twelve to fifteen of them in the boats, and the crews thought nothing of devouring eight roasted swans in a day.

(Source: Marli River Park document – An Interpretation Plan. Swan River Trust - 2014).

Bull sharks (or River Whaler) grow to a length of about 3.4m and are the only shark species known to stay for extended periods in freshwater. A Bull Shark is thought to have been responsible for at least one death in the Swan River but there have been several attacks, and the sharks have been caught as far upstream as the Maylands Yacht Club.

Low oxygen levels are another issue with which the Swan River Trust is grappling. The major cause is the microbial breakdown of organic matter. Organic material such as leaves and algae enters the river system, and naturally occurring microbes use oxygen to

break down the matter. Oxygen levels can often drop quickly as the microbes respond to organic matter loading events, particularly in warm weather. In some cases, when the saltwater moves in a wedge from the estuary mouth at Fremantle during the summer, water at the surface of the river does not mix with the saline water which is heavier and sinks to the bottom. Microbial activity in the salty bottom water continues to consume oxygen, but this oxygen does not get replenished from surface water. As well as dealing with the issues of the organic and nutrient load entering the system, the Swan River Trust monitors water quality and has a short-term solution to deal with the issue. The

oxygenation program provides oxygen to targeted areas of the river through four oxygenation plants; at Caversham and Guildford on the Swan River, and two plants upstream of the Kent Street Weir on the Canning River.

(Source: Marli River Park document – An Interpretation Plan. Swan River Trust - 2014).

There is a history of bathing in the swan river with opportunities for formalised bathing previously available at the Claremont Baths, Matilda Bay Baths, and Perth City Baths. With all of these bathing pavilions now long gone, this concept for the ‘River Pods’ provides opportunity for safe bathing in the river once again.

This concept for river pods is intended to provide a safe place for river swimming centrally to the pods protected via a shark-net, while the perimeter provides opportunities for boats to moor. Private boats could temporarily pull up to the pods in a similar way as is possible at Elizabeth Key for a limited amount of time. To ensure that the pods are egalitarian, there is a larger docking opportunity that is intended for a river taxi service to provide access to the pods for everyone. A series of these pods are proposed for locations along the river where they are more protected from the cold afternoon sea breezes. There is potential for a food and beverage boat to service each pod on rotation to provide food and drinks to those spending time on a river pod.

These pods would not only serve for exercise and entertainment, but they would also benefit the river system through being a source of oxygenation and mussel cultivation.

When Neil was first in Copenhagen, he became aware that the boardwalks that ran alongside and into the harbour were the main structure for the netting that contained the cultivation of mussels. Local school children were introduced to the cultivation and harvesting of mussels in small groups of snorkelling excursions below the boardwalks. We too have opportunity to recreate such an experience. The mussels filter out nitrogen and phosphorus from the water, two substances that cause serious problems in terms of marine eutrophication. However, as long as the mussel biomass remains in the water, they provide no net effect. The filtering benefits of the mussels can be increased if the mussels are consequently harvested. By cultivating mussels, we are not only ensuring cleaner water due to their filtration process, but we are providing opportunity to provide a food source for our community. A regenerative process that can co-exist with the other functions of the proposed River Pods. Neil’s scheme provides a protective shark net to the perimeter of the circular boardwalk component of the design. This netting also serves as the trellis for the cultivation of the mussels.

These proposed River Pods also provide opportunity to artificially oxygenate the river through oxygenation plants that would be located below the pod decks with potential for the oxygen outlets at low river bed levels at the outer edge of each jetty.

From the WA Department of Water and Environmental Regulation: ‘Low oxygen concentrations is a symptom of excessive nutrients entering waterways from surrounding urban and agricultural land - a process known as eutrophication. Excessive nutrients can accelerate the growth of aquatic plants and algae, which consume oxygen over-night when they respire, as well as through degradation processes when they die. Oxygen is also consumed by chemical reactions occurring in the top layers of the sediment. 

Oxygen is naturally replenished by transfer from the overlying air, mixing (via wind or flow) and the photosynthesis of aquatic plants and algae during the day. However, in highly eutrophic systems, oxygen is consumed faster than it is replenished, and concentrations decline, sometimes to the point the water body is completely devoid of oxygen. 

Oxygen is essential for most aquatic life. Low dissolved oxygen impacts on the healthy functioning of the ecosystem and may cause acute stress and death to marine life. The Department of Water and Environmental Regulation began trialling artificial oxygenation to supplement excessive oxygen demands and mitigate the symptoms of low oxygen in 1998–1999 both with a land-based plant on the Canning and a barge-mounted plant on the Swan. The success of trials led to artificial oxygenation becoming a long-term management tool for the Swan-Canning estuary. Four oxygenation plants are now managed and operated by Department of Biodiversity, Conservation and Attractions, two on the upper Swan at Guildford and Caversham, and two on the Canning River above the Kent St weir at Bacon St and Nicholson Rd.’

The proposed series of River Pods provide opportunities for the WA Department of Water and Environment Regulation to expand their points of oxygenation to the Swan & Canning Rivers. River health can be improved further through the cultivation of mussels for harvesting within the perimeter of the River Pods.

Solar PV rooftop panels to the canopy will provide the energy for the oxygenation system. The River Pods also provide educational opportunities for school children to experience the mussel cultivation and harvesting.