Design Interventions to the Gnangara Mound



For centuries water has been a part of human culture in numerous aspects. The public baths of the Romans exemplified not only the cultural significance of water and bathing, but also the part played by water as an architectural element in its own right. Early Incan civilizations planned out vast areas based on water sources and water management strategies. Examples such as these have influenced the development of societies for centuries. However, the notion of water as an invaluable resource is scarcely evident in contemporary Australia. Rather, water is treated as a cheap, albeit essential, commodity simply there to serve its purpose.

This design project proposes several water based interventions that broadly look at Perth’s Gnangara Mound, which extends from the Swan River to the south to Gingin Brook to the north and the Darling Escarpment to the east. The several sites of focus will incorporate various land use types dealing with; empty rail reserves, dense urban space, residential areas, degraded, or abandoned quarry/tip sites and will examine an area of the pine plantations. The intent of these design interventions is to speculate about ways in which architecture and the ecology can coexist such that water becomes the focal point. Architecture must play a role in addressing this water crisis since architects are the custodians of maintaining a survival of the landscape. The three key issues the design focuses on are; creating a visual awareness of the water within society, innovation in design when creating a sustainable future, and the role architecture can play in creating an overwhelming ephemeral experience of the water, educating people of its value.

The Gnangara Mound is Western Australia’s largest groundwater system, covering approximately 2200km2 and supplying up to 60% of Perth’s water. The superficial aquifer below is used as a key water source for not only residential, but also industrial, agricultural, horticultural and recreational areas. It is viewed as the most precious water source in Australia. During the period 2004-2007, reports indicate that about 298GL/yr were abstracted from the mound to sustain the greater Perth community. However, after groundwater recharge and discharge to the ocean, the amount of recharge available for sustainable abstraction amounts to only 160GL. The abstraction of water beyond sustainable levels causes a major reduction in groundwater levels from year to year. The resultant decline in the water table, and its social, cultural and environmental impacts will only worsen with the rapidly increasing urban developments on the Mound. One of the key challenges today is to make people aware of the water problem, change attitudes to water, and encourage sustainable use of water in order to ensure adequate recharge of the aquifer beneath the Gnangara Mound.

The Gnangara Sustainability Strategy (GSS) is an initiative that was developed in attempt to improve future usage of the Mound. The GSS suggests that, based on several scenarios, land-use management activities, including burning native vegetation at regular intervals and removing the pine plantations to the north, can assist in stopping the water table decline. The removal of the pine plantations, however, needs to be managed as a staged process so as not to dramatically increase salinity, a factor this brief looks to address. The intent will be to provide a possible solution to each site of focus to both improve water usage and water abstraction from the aquifer.

The superficial aquifer, the underlying water body of the Gnangara Mound, needs to be a point of focus for future land usages since it is the most valuable resource for the greater Perth region. Studies of Perth water consumption over recent years suggest that about 50-60% of sourced water still comes from groundwater supplies. This puts a major strain on the superficial aquifer to retain an adequate volume and flow of water without drying up. While the two larger aquifers below the superficial aquifer, the Leederville and the Yarragadee, are also used for water sourcing, the depth at which they sit in comparison to the superficial aquifer makes it uneconomical to draw water from them. Studies indicate that during the period 2008-2009 the total residential water consumption was around 175 000 ML for the Perth region, with the average residential property consuming 277kL per annum. After examining the economic and cultural value of water, one could assume that it would become more beneficial to consider other means of providing water to society through reducing abstraction and increasing ground water recharge. The future of the superficial aquifer needs to be a return to a state of equilibrium.

Design is the key to ensure a future for Perth. Water is the most valuable resource we have, the aim, now, is to make people aware of it!