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take a leak


Pub: Sydney Morning Herald

Pubdate: 05-Mar-2009

Edition: First

Section: News and Features

Subsection: Opinion

Page: 15

Wordcount: 838

A lonely tree cries out for a drink in a city ruled by uncivil engineers


Evidence that engineers are vastly over-represented among the ranks of international terrorists will come as no surprise to architects, who are accustomed to picking up what few pieces are left after engineers have done their worst. Now, however, it seems there may be a yet more sinister engineering plot against the civilised world.

Somewhere near the start of Glebe Point Road there is a tree, perhaps a poplar. It is in many ways a microcosm; it could be any street tree in any city in Australia. But this particular street makes an especially poignant example, since the council has just finished a long, slow refurb of same, at considerable expense and no small disruption.

And engineers? What has the tree to do with them? Well, this. Post-modernism may have come and almost gone but the road engineer still rules where matters traffic are concerned. The people who brought us cloverleaf interchanges and 10-lane flyovers have not gone away. They may be retiring but they have not retired. Far from it.

In contemporary street design, everything that matters – which is to say the trafficable space, the carriageway – is designed by engineers. And everything that doesn’t matter – which is to say the public, pedestrian space – is designed by, well, designers. Pansies.

The engineers’ bit, the carriageway, is determined by all sorts of self-important, clearly set out and quantified standards, Australian Standards no less, that govern structure, hardness, dimension, grade, camber and porosity, to name a few. The public bit, on the other hand, is largely subject to wishy washy discretionary forces; aesthetics, politics, whim and fashion.

And there’s the rub. For the tree, which stands at an odd, slightly wistful angle and whose leaves are tired-looking even at this harvest festival moment in the calendar, has a problem. February is often our wettest month but for the tree it has been a long time between drinks. Around its base is about half a square metre of that porous faux dogfood with which they apron trees these days, reducing root-compression while admitting rain. But the area of the dogfood is only around a tenth that of the root-ball, so that not much falls there and most of what does, runs off into the gutter instead of soaking in.

Said gutter, directly adjacent this small tree patch, is a smart new square-jawed pre-cast concrete job that proudly declares its intention and capacity to conduct stormwater to the bay. Hence the poplar’s wistfulness. Its roots may twist within centimetres of this rushing, gurgling stream, happy as a newborn, but access has it none. It must spend every shower and every rainstorm being tantalised, teased, then deprived.

The result is a tree in torture. It fails to thrive, drops its leaves, looks miserable. More significantly, the shade decrement means that all those hot black surfaces – asphalt on the carriageway, black terrazzo pavers on the footpaths, – bake beneath unmediated solar radiation.

In cases like Sydney Uni, Cleveland Street and much of Chippendale, where shady, spreading, deciduous exotics have been assiduously replaced by politically correct, low-water, shade-stingy natives, you don’t even have to torture the trees to get this heat-island effect.

So the local microclimate thus gets hotter, and hotter, and hotter – some 6-10 degrees hotter, estimates sustainability coach Michael Mobbs. This drives shoppers into their cars and air-conditioned malls and spins the planet further down its climate change vortex.

So here’s the question. Is it possible for local government engineers to design a leaky gutter? Or for designers to plant trees below road level?

Demonstrably yes to the second. Green Square, for example, where the median strips are designed as reeded stormwater swales. It can be done, yes, but seldom is. Take the dying palms along Moore Park Road; the median strip is raised to ankle height, doubling as a traffic barrier, so the trees are cactus.

But engineers and leaky drains? Is that even conceivable? Everything natural leaks, just like everything edible rots. But tell an engineer that a good drain is a leaky drain and he’ll burst a blood vessel.

Engineers, at least of the local government variety, are dinosaurs in modernist bog, where only the quantifiable exists and problems must be shorn, oversimplified, and solved in isolation. This is not that kind of problem.

Every year nearly 2000 megalitres of stormwater washes our street filth (the non-human variety) into Blackwattle Bay, already one of the most toxic patches of sea bottom. The City Council, understandably concerned, runs a Blackwattle Bay Stormwater Abatement program. It gets special state funding to do really useful things like give away 22,000 consciousness-raising postcards and install fish-design stormwater grates to remind would-be butt-chuckers of their marine obligations.

They even run street-cleaning programs especially to cleanse the runoff. But to reduce the runoff itself? A leaky drain along every street and park would amount to a civilising jihad; feeding trees, cooling streets, greening parks, reducing climate change, softening the urban experience and keeping the muck on land, where it belongs. Way too simple.


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