2030 Sea Change
Strange but True
|Team||Stutterheim / Anderson Landscape Architecture|
We know we live on the continent whose most constant rhythm is its climatic inconsistency. We accept this as inevitable to the extent that we have done little to understand and
counteract behaviour that damages the delicate balances of the system. As this recognition dawns, we need to come to terms with the implications of a volatile and quickly emerging environmental complexity, greater than any known to modern man. What we do know already is that the most physical effect on us of the isotherms broadening out from
the equator will be an uncomfortable rise in local temperature and wild storms that damage the infrastructures we have created. The saddest loss will be the sounds and beautiful
strangeness of animal and vegetation species who will fail when starved of the specific conditions provided by the climatic bands they have adapted to. But the most obvious effect
on the urban structures of Sydney Harbour will be the unpredictable rise in sea level caused by melting arctic ice and the expansion of the heated oceans.
Over the coming centuries this will progressively reshape our shorelines, reconfiguring our urban edges and creating an array of new spatial typologies. Responding to these challenges by protecting and retrofitting the valuable urban edges, established over 200 years with raised sea walls, can stave off predicted losses within the 400 - 900mm parameters of this competition, as well as produce re-imagined landscapes of raised paths, dynamic ramps and jetties, tidal pools, higher viewing areas, and new forms of green infrastructure such as interstitial terrains counter-intuitively sloped away from the sea.
But such defensive moves as raised walls initiates a raft of intractable side effects: most urgently the drowning of existing drainage infrastructure. Already the saline ‘valley’ produced by sea back flowing ‘up’ on to our streets and into low lying coastal areas is killing street trees along the coastal drainage lines. This condition is the precursor to greater effects to come, despite possible technical ‘quick fixes’ such as one way valves in softended floppy drains. Fortunate in this regard, Sydney’s harbour has a built-in temporary safeguard. Due to its topography, the rising sea levels will more gradually impact the steeply rising sandstoneflanks, sculpted, here as at Rushutters Bay, by the narrow streams that have eroded the peninsula of this sunken valley. Thus there is time for the incremental ameliorative processes identified in the brief.
However, the complexity of these ameliorative processes are compounded by our growing realisation that our most valuable asset is freshwater, and our first responsibility is to keep this ’wet gold’ in public ownership. To do this we need to collect it, clean it, and store it for public use. An easily overlooked aspect of water is the discrepancy of saline and sweet water value: to lose rain into less clean water is to be avoided, and to lose it into salt water avoided at all costs.
To prevent the accumulation of freshwater at the meeting with changing sea level will necessitate strategies of progressively higher level water collection. Along with a redesigned water infrastructure which coordinates a range of tactics - rainwater collection tanks, storm water runoff re-directed for ecological treatment before reuse as urban space irrigation; grey water treatment at the base of high buildings and high pressure reverse osmosis for irrigation in food production; off peak piping of water to inland low points – a strategy of appropriating the increasingly obsolete infrastructure and architecture at the shifting coastal edge will be needed to store accumulated water. Sequentially, large tanks might be placed on/under sites and houses, as far uphill as possible. Simultaneously, replacement of threatened coastline trees needs to be anticipated by planting new stock up the slopes, as shown in the sections.
Beyond this, storm water in large quantities will continue to flow down across these slopes. Storm water, in effect, is waste, unless improved for urban irrigation by wetlands. But such an approach is impossible on Rushcutters Bay’s rising terrain and little evidence of healthy ecosystems exists. To achieve storm water which is ecologically acceptable requires land, aeration, or mechanically separated contaminants. Once clean enough, this water can provide urban irrigation, or may be released to the sea, where not contained by raised walls, across almost forgotten kinds of urban recreational spaces of rush beds and cultivated Mangroves, now appropriate to this more tropical climate with its associated Birds, Plants and Animals.
Alternatively, inland, up the groins of the peninsula, low weirs holding back ponds - ecological niches of water plants in the valley streams - will aerate and cleanse stormwater. These green infrastructures may be explored through networks of roving paths and overhead bridges, and provide a range of dynamic open programmed public spaces, as in the collages.
Strangely and excitingly, sea rise converging with associated water management issues will drive the establishment of new inter-tidal ecosystems such as mangrove and salt marsh habitats, and generate a proliferation of new hybrid urban ecologies. Within these new hybrid ecologies, new urban configurations arise, new human habitats take shape, and innovative circulation systems and land-sea-air connections are made. In particular, we envisage the emergence of a new interchange hub located above the 5 metre sea level. This allows for an increasingly waterbased community to alight onto a major Urban Platform, itself the roof of an enormous water tank, and move up to a Super Rail deck for transition into the wider urban agglomeration.
Sea Change 2030 - competition entry
Sea Change 2030 - plan
Sea Change 2030 - views
Sea Change 2030 - sections