In praise of sewage

“Cockle Creek? Ooo, I wouldn’t put in there” my sister’s mate, the local, said “They’ve been dumping heavy metals in that spot for years! And there’s the sewage farm up the river as well.  I’d steer well clear”.

I muttered to my sister as we walked away “What do you think? Are you worried about heavy metals and sewage?”

“Nah!  Let’s do it!”

Sunrise on Lake Macquarie

Sunrise on Lake Macquarie

The power of poo.  Over the last couple of years, I’ve been hearing a lot about it from my fabulous friend and colleague, Cath Simpson, at this very minute writing a documentary for Radio National full of plops and splashes.

Thanks to some bad experiences with cholera and typhoid, we modern city dwellers generally a bit iffy about human excrement. But the bacteria that dwell in and on us – our own personal ecosystems – seem to be quite critical to human health.   While I’m a huge fan of the toilet, poo is not all bad.  If you have a nasty case of Clostridium difficile, for instance – an infection that kills 30,000 Americans every year, often older people in hospitals who have had their bacterial ecosystems depopulated by antibiotics – a “faecal transplant” from a healthy donor is might well be your best chance of a cure.

If the much of Western world, with its convenient superphosphate fertiliser and cow-pat free central heating, has been a bit “ew” about excrement, one sub-culture has held the faith.  Bird watchers have never lost confidence in the value of ordure.

Cormorant diving crop for trim

Painterly pied cormorant fishing in Lake Macquarie

When Birdlife Australia asks “where’s your favourite birdwatching spot?”, do you choose an offshore island, fringed with white sand?  the lush splendour of the tropical rainforest?  Or choice number three, a sewage treatment plant? And you guessed it, the first comment is a ringing endorsement of the glories of the Alice Springs Sewage Ponds.

So I wasn’t really surprised at the new and exciting birdlife I saw up  Cockle Creek in amongst the drowned computer monitors, abandoned bridge footings and Impressionist riverscapes subtly enhanced by a discreet discarded tyre.

So many striated herons I got bored of taking photos.  White-cheeked honeyeaters.  Orioles.  Black faced cuckoo shrikes. White breasted woodswallows, showing off their 80s batwing styling.   Double-banded finches with their neat dress shirts, black ties and cummerbunds.

Why are sewage treatment plants so great for birds?  Well, wetlands are a particularly threatened habitat – a third of Victoria’s wetlands have been drained over the last two hundred years, for instance – and old-style sewage ponds offer alternative places for birds to feed and rest, especially during droughts.  With plenty of nutrients, the settling ponds of sewage treatment plants actually offer more invertebrate snacks than natural wetlands, and sustain a greater range birds. Christopher Murray’s research in Victoria has found that newer treatment plants – the dynamic sounding “activated sludge” facilities – that take up less expensive real estate than old-fashioned waste stabilisation ponds (and smell better) are less appealing from a waterbird’s point of view.

If the news on sewage plants is pretty good, I’m not so sure about the heavy metals. Cockle Creek really has been a dumping ground for cadmium and lead, among other things, from the smelter in Boolaroo, on and off for more than a century.  There’s black slag from the plant tucked away in all sorts of unexpected places around the lake shore and lead, zinc, mercury and cadmium lurk in the creek’s sediment, 70 centimetres deep.

The smelter closed down in the noughties and the site is still being “remediated” for housing.  Previous “abatement” strategies seemed to involve scraping off a few centimetres of topsoil and (after most of the local pre-schoolers were found to have worryingly high levels of lead in their blood) urging kids to  “Wash wipe and scrape – you’ll be right mate!”. In the 1980s and early 1990s, the streets closest to the “The Sulphide” were rented out on the strict condition that the household should have no children or pets.

There’s a giant Bunnings there already, though, amidst the rubble.  Perhaps the logic is that the visiting DIYers are heading home to put a mallet through an asbestos wall, so where’s the harm in throwing in a spot of bonus lead?

The local birds seem to be doing okay, though.  A pair of ospreys nest at the top of a Norfolk pine at Speers Point, where Cockle Creek flows into Lake Macquarie, and this last year they’ve had chicks.  Osprey are locavores and since they’re at the top of the food chain, anything toxic in the fish they eat ends up in their chicks.  Eventually.  It takes a while for our endlessly updated array of contaminants – from DDT to teflon, fire retardants and hypertension medications – to make it into the bloodstream of the baby raptors.

Osprey wings bent crop wide

Osprey with fish at Speers Point, Lake Macquarie

I’ll be back to Cockle Creek for sure, to see what the local sewage has in store for me.  Trying to tread lightly, and hoping not to feel too much lead and mercury squelching between my toes…

D in canoe at dawn small more waterReferences

Murray, C. G. & Hamilton, A. J. (2010). Perspectives on wastewater treatment wetlands and waterbird conservation. Journal of Applied Ecology, 47(5), 976–985. DOI: 10.1111/j.1365-2664.2010.01853.x

Murray, C. G., Loyn, R. H., Kasel, S., Hepworth, G., Stamation, K. & Hamilton, A. J. (2012). What can a database compiled over 22 years tell us about the use of different types of wetlands by waterfowl in south-eastern Australian summers? Emu: Austral Ornithology, 112(3), 209–217. DOI: 10.1071/MU11070

Murray, C. G., Kasel, S., Szantyr, E., Barratt, R. & Hamilton, A. J. (2013). Waterbird use of different treatment stages in waste-stabilisation pond systems. Emu: Austral Ornithology. DOI: 10.1071/MU12121

Murray, C. G. & Hamilton, A. J. (2012). Sewage ponds a refuge for wetland-deprived birds. ECOS, 175. http://www.ecosmagazine.com/?paper=EC12418

A bridge fetishist paddles to Brooklyn

I have a weakness for bridges.  Romantic trysts just happen to be arranged with the backdrop of the world’s first iron bridge.  Multiple crossings of the gorgeous Severn Suspension Bridge are absolutely essential for that work trip.  And in pride of place of the mantlepiece, of course, is a railway poster of the famous cantilever bridge over the Firth of Forth.

So perhaps it’s not surprising that my paddles lately all seem to end up under what it pleases me to call Brooklyn Bridge.  That’s not its real name, mind, but since it starts  on Long Island and takes you through the thriving metropolis of Brooklyn (population 744) I think I can get away with it.

Brooklyn bridge and stone pillars plus boat.jpg

There was that morning jaunt from Parsley Bay, past the oyster leases and beneath the swooping welcome swallows, to the top of Mullet Creek, where the Newcastle trains disappear into the Woy Woy tunnel, once the longest tunnel in the southern hemisphere.

I’ve been lucky enough to go on on some beautiful railway journeys in my life – from Montreal to New York in winter, past above-ground swimming pools frozen like giants’ ice-cubes; from southern Thailand to Bangkok, looking out at the richest of tropical orchards woven into the jungle; between snowcapped mountains and sea on the West Highland line to Hogwarts Mallaig.  But I reckon this journey along Mullet Creek, not a place that will ever be immortalised in the baby names of the rich and famous, is my favourite.  There’s something about a railway line that leaves roads far behind, forging its own way along the empty shore.

Sunrise at Brooklyn

If you ask the driver, you can get off near the top of the creek at Wondabyne, the only station sans road access in Australia.  Every now and then, you see people jumping off the train and straight into a tinnie, zooming off to the shacks on the other side of the river before their fish supper gets cold.

For a few years in the late nineteenth century, while the first Hawkesbury River bridge was being built, if you were travelling north by train from Sydney, you would disembark at Long Island, board the double-decker paddleboat the General Gordon, and steam off to Mullet Creek Station, then just north of Wondabyne.  Now people hop off here to do part of the Great North Walk – a 250 kilometre walk from central Sydney to the beautiful beaches of Newcastle – or to wander up to Pindar Cave.  Judging from the smorgasborg of rusted out craft I saw in the shallow water at the top of the creek, it’s also a place where people take their boats to die.

Then there was this weekend’s jaunt, downriver from Deerubbin Reserve – a popular spot, right by the freeway, to fish or have a picnic for those who find the perpetual roar of traffic reassuring.  With the ever present possibility of a quick exit, I guess it’s ideal for the heavily pregnant or those who find their relatives a bit hard to take.  But I can’t really bag people for their passion for the internal combustion engine since I get all hot and bothered at the prospect of a paddle underneath (count ’em) three great big bridges.

This weekend’s jaunt took me past Spectacle Island Nature Reserve, under the Hawkesbury River Railway Bridge, natch, and around Dangar Island, swished along smartly by the current and the falling tide.

Have you ever been bored enough in an airport to try walking  the wrong way up a moving footpath?  Trying to paddle across the current to get to one of the beaches on the eastern side of the island was a bit like that.  It all seemed a bit too hard in the end, so I went where the river wanted to take me, downstream, floating just above perilous rocky reefs by off Bradley’s Beach and veering round the seagrass beds.

And then through the sailing boats, swaying and tinkling like expensive marine windchimes, to Sandy Bay, the best place in the world to be homeless.  The folks whose setup I saw there – a tarp flanked by a beached ramshackle boat and a solar panel – had no-one for neighbours but a horde of blue soldier crabs.  There was no sign of the human residents, but I now know what it’s like to be a celebrity, thousands of beady eyes watching and waiting on your every move.

Quite a few people live rough around Brooklyn.  “Good caves, a shower at Brooklyn Baths and walking distance to the bottle shop”, as RB commented with unseemly enthusiasm.  In the Depression, apparently, lots of people came to live in these parts for just this reason – shelter and a bit of space for chooks or a veggie garden.  I didn’t see a chicken run in Sandy Bay but Brooklyn does seem to have some kind of common flock, judging from these good looking fellas that we met down by the marina a while back.

I reckon the Hawkesbury estuary is Sydney Harbour through the looking glass – a parallel flooded river valley, bordered by bush instead of multimillion dollar apartments.  If the Harbour has its iconic Bridge, the Hawkesbury has its own engineering marvel – nearly three times as long, resting 50 metres and more deep in soft black mud.

The modern bridge is the second one to cross the river here.  The old bridge, finished in 1887, was the last link in the railway that spanned four colonies, connecting Queensland to South Australia.

Sir Henry Parkes, on the day of the bridge’s official opening, pronounced: “In this great system of material arteries which we completed today, we see the crimson fluid of kinship coursing through all the iron veins” (Sharp, 2001, 4).  Apparently the other grandees were a bit more underwhelmed by the prospect of a federated Australia, bound together with railways.  Nonetheless, the day after, the headline in the Sydney Morning Herald was headline was “United Australia”

Bridge silhouette 1

At the time it was built, the old bridge was the longest in Australia and had the deepest footings in the world – 180 feet below the high water line – though they still didn’t reach solid ground.

The Union Bridge Company from New Jersey won the contract to build it (on a pin-jointed truss system, as I’m sure you want to know), giving Brooklyn, the railway town that was set up to house the workers, its American name.  The tender being won by an American company was one in the eye for the old country, though it pleases me in some strange way that the riveted steel for the spans was made by Arrol Brothers in Glasgow, who also worked on the bridge across the Firth of Forth.

But the original Hawkesbury River Railway Bridge didn’t last.  Its piers, filled with rubble instead of solid concrete, fractured under the weight of the trains that crossed here, the only  bit of duplicate track on the line.  The piles were starting to crack in the 30s, but the problem only came to light when a US railway geek doing a bit of light recreational reading of an engineering textbook spotted that the piles weren’t built to the original specifications.  The death knell of the old bridge, though, was the extra rail traffic of the war.

The piers of the old bridge remain, like golden castles guarding the river.

Castles 2

The footings of the 1887 Hawkesbury River Railway Bridge.  Or castles as I like to call them.

I’ve had a great time reading the fantastically detailed history of the building of the new bridge by Major-General Albert Cecil Fewtrell, the Chief Civil Engineer of the NSW railways, who supervised its completion.

There’s some entertaining reading between the lines.  When it came to putting the metal spans onto the concrete footing, it seems some fool had a plan to float the 1,600 tonne metal spans over to the pilings at water level and then haul them out with giant cranes perched on the piers.  But Major-General Fewtrell soon sorted them out:

“Consideration had been given early to the proposal to float out the spans at low level … The decision [was made] to revert to the high level method of floatation following the return of the Author from active service in 1943” (Fewtrell, 1946, 27)

The prep they did for the task of floating the massive spans from the construction docks – the cuttings still visible on the north shore of Long Island – onto the concrete pilings at high tide also gives you a sense of the guy.

A large board, representing the land and water at the site of the new bridge, was laid down in the southern tunnel. Model piers were accurately fixed in position in the “stream,” and miniature spans, pontoons, and equipment were used so that the men could practice in detail movements and prepare for emergencies.

Don’t you want to play with those 1/32 scale tiny cranes and miniature pilings?  I really really do.

Fewtrell thought that everything had gone swimmingly.  But the new bridge, the bridge that was supposed to last 200 years, is crumbling.  After years of delays, just this last week, work started on repairing the concrete footings and its rusting reinforcing steel. When I paddled past, there were huddled men in high vis jackets and mysterious icons dangling from the bridge deck – all the signs that a new engineering miracle is about to begin.  And I’m sure it’ll happen.

But at this stage, once again, I reckon it’s Hawkesbury River 1: human engineering 0.

How to murder your monster shrubbery

The short answer is “slowly and with feeling”.  But let’s not rush into anything.

I’m pretty sure there’s some kind of by-law in Hornsby Shire against putting your kids to bed with a recitation of “The Love Song of J Alfred Prufrock”.  Something along the lines of the “Unsafe and age-inappropriate use of modernist poetry act of 1987”.  But when your eight year old requests read T.S.Eliot, what can you do?

 

I don’t think I’m exaggerating when if I say that T.S. seemed to be a teeny bit negative about ageing.  One can only speculate on how different this poem (and indeed his whole oeuvre) would be if Prufrock had focussed less on getting lucky with the sirens of the sea and more on pruning.

Because, let’s face it, gardening is an oldie’s game.  When, yet again, the annual spud harvest fits in a single soup bowl; when your carrots are absurdly abbreviated; when another fruitless year passes for the ungrateful kiwifruit vine, the middle aged gardener shrugs her shoulders and thinks “next year”.  The seasons tumbling past faster and faster just means a shorter delay before you have another go at germinating those ruby brusselsprouts.

Our Fraser Island creeper finally did its gaudy thing – flaunting great big, hot-pink clusters of flowers in the oddest place, not up where the growing fronds reach  towards the light but way, way down in the gloom underneath the rampant Sweetie kiwifruit vine.  It flowers on old wood.  What a fine turn of phrase!

The Tecomanthi hillii not alone in dragging its feet.  Here’s a wall of shame – some other plants that have taken their sweet time to do anything exciting at all.  At least the “Bower of Beauty” has finally decided to flower on our side of the fence, rather than, like it did last year, offering a display exclusively to he neighbours.

It seems fitting, then we’ve taken what might be politely described as a contemplative approach to the execution of the massive weeds that tower over our back garden.

Our broad-leafed privet rivals the great redwoods of North America.  We have a Japanese honeysuckle vine as gnarled and vigorous as a strangler fig, which scrambles through a hibiscus “bush” as tall as a two story building. If only the mystical growth potion that the erstwhile owners  poured on these doughty invasive plants would seep down the hill into my peaky looking zucchini plants.

I like to think incremental approach to weed-murder has some ecological justification.  Some weeds in some places – lantana, for instance – form a critical habitat, particularly for the smaller birds that have been disappearing from cities.  If you clear it without replacing it, the LBBs vanish too.

So over the last couple of years, as well as installing a spiky tangle of hakeas, callistomens, sorbs, grasses and vines in an out of the way corner of the yard, I’ve  been tracking down native fruit-bearing plants to replace the  tainted bounty of the privet and honeysuckle berries.  Purely in the interest of hungry birdlife, you understand.  Nothing to do with fetishistic plant-hoarding.

Daleys up in Maleny and The Good Karma Farmer in Newcastle are my bushtucker dealers.  In my experience, you can tell if it’s bushtucker because the critters get it before you.  Following this logic, I’ve put in lillypillies, native gardenia and Davidson’s plum, koda for the Lewin’s honey eaters and the brown cuckoo doves and blueberry ash for the wonga pigeons.  I’m fairly confident the birds won’t turn their noses up at the mulberries, the persimmons, my grapes, my persimmons and my cherries either, damn their eyes.

I’m still working on substitutes for the honeysuckle and the fine looking but weedy red trumpet vine we inherited from our house’s old occupants.   Along with the hibiscus, they’re a favourite of our regulars, the little wattlebirds, and the gorgeous eastern spinebill, an all too occasional visitor.

I’m slowly sliding the wonga wonga vines, the Bower of Beauty, the dusky coral peas and the guinea vines amongst the potato vines and the honeysuckle.  Lulling the evil invaders into a false sense of security before I strike… there will be time…

“There will be time, there will be time
To prepare a face to meet the faces that you meet;
There will be time to murder and create,
And time for all the works and days of hands
That lift and drop a question on your plate;
Time for you and time for me,
And time yet for a hundred indecisions,
And for a hundred visions and revisions,
Before the taking of a toast and tea.”

You see, Prufrock definitely has the makings of a gardener.  You may well murder and create after your hundred indecisions, visions and revisions, but don’t forget that cuppa tea*.

*Health and safety warning: this is a gardening blog, not a work of literary criticism.  No responsibility is taken for any adverse horticultural outcomes of incorrect readings of the Western literary canon.

Two sad islands, three whistling kites

It’s 7 o’clock on a midwinter Sunday morning.  It’s five degrees C.  And I’m about to go canoeing.

The thought that I may be slightly mad has passed through my mind.  A key motivation for hauling myself out of bed before sunrise was to try to get a better look at the whistling kite that hurtled past me into the distance last time I put the kayak in at Mooney Mooney.  And as I’m standing in my innovative Milan-style long-johns and wetsuit combination, what do I spy, perched in a dead tree right above the car park, but a whistling kite, defrosting in the first light.  Tempting get that pic and hightail it back to bed.

But no, Bar Island is calling me.  I’m heading back to the spot where I first decided, on a boatie camping trip just up the river at Back Beaches, that my mental health demanded the purchase of a cheap canoe.  And halfway across the river, when the first rays of the morning sun hit me, I feel truly blessed.

Bearing in mind my favourite quote from Antonio Gramsci (“pessimism of the intellect, optimism of the will”), I started out my jaunt by heading across to Olga Bay. Last time I was there, a magnificent white bellied sea eagle swooped through the golden afternoon sunshine and snatched a fish from the briny right in front of the boat.

Unfortunately, convinced that the Hawkesbury was going to sweep me out to sea, at the time I had my head down, as I blasted my way across the river.  The David Attenborough moment passed while I was fumbling around in the dank reaches of the canoe for my much abused camera.

Needless to say, the sea eagle didn’t do a repeat performance, though that Australian darter that I pursued heartlessly from perch to desperate perch up the Wyong River last weekend had an unpleasant surprise on that therapeutic holiday to a little hire cottage on Milson’s Passage that the doctor ordered.

Bar Island greeted me with the green flash of (what I think was) a sacred kingfisher watching from the mangroves as I clambered awkwardly (camera-less, of course) over the slippery rocks to the shore.

To be honest, I found it a gloomy place, weighed down by history and hemmed in by trees.  They’re important trees – casuarina glauca for the glossy black cockatoos and red ash which, according to the informative signs, feeds the copper jewel butterfly.  Perhaps I’ve been living with a Scotsman too long.  I have started to share his culture’s love of denuded landscapes and the sweeping views created by sheep, deer and industrialisation. We’ve dubbed the accompanying fear of excessive greenery “wood psychosis”.  There was a bit of wood psychosis going on in Bar Island this weekend.

And then there’s visible colonial history of the place.  St John’s Church was built on Bar Island in the 1870s, and the grave stones of some of the sixty or so European settlers who are known to have been buried there remain, along with reminders of the troubled history of the Hawkesbury as a brutal contact zone.  “A difficult time” as the plaque commemorated Sarah “Granny” Lewis carefully puts it.

The best spot to be on Bar Island on a chilly winter morning was, not coincidentally, the wooden seat near the midden on the northern tip of the island.  The midden’s metres deep, accrued over thousands of years of shared oyster eating by Darug, Darkinjung and Guringai people, whose country meets here.

And not far away, the resident kite and her nest, were also basking in sunlight.  RB has been working here, on and off, for three years, and the nest has been there for at least that long, renovated and extended each season.  The kite wasn’t moving, despite the clumsy paddling and clicking camera.  It’s her island now, and she knows it.

I thought I was smart, timing my trip upstream with a rising tide.  I wasn’t feeling quite so clever heading downriver again as I tried to take a racing line across an sharp S bend, with the current and the tide battling it out all round me.

First I ploughed exceedingly slowly, on that perfectly still day, through a stretch of strange standing waves.  And then I found myself swirling through a sequence of weird vortices, that churned up silt and the occasional jelly blubber.  I read Lisa-ann Gershwin’s Stung! On Jellyfish Blooms and the Future of the Oceans a while ago.  She concludes, to put it bluntly, that we should enjoy fish while they last, as the jellyfish, floating around in the oceans since the pre-Cambrian, are on their way back with a vengeance, thanks to acidified, over-fertilised and over-fished oceans (not to mention climate change).

Since then I see every jellyfish as a portent of doom.  Given this slightly apocalyptic worldview, after about an hour and a half trying to escape this turbid hellhole (okay, it was about ten minutes) I began to worry that one of those whirlpools were going to suck me down into the bowels of the river, just the icefloes in this extremely spooky youtube find.

Needless to say, I survived The Whirlpool of Death.  In marked contrast to many of the people who went to live at Peat Island, which I paddled past on the last leg of my route home. Built to detox alcoholics early in the twentieth century, the site was used for over ninety years mainly as an asylum for people with mental illnesses or learning difficulties.  From all reports it was a horrifying place where inmates were caged, neglected and sexually abused.

The last residents, treated somewhat less brutally than those who came before, left in 2010, and the site is now padlocked and empty, awaiting redevelopment into a 250 berth marina and suite of five storey apartment blocks.  Because there’s nothing that says “high density living” and “brownfield site” like a place with national parks on all four sides.

I spotted one last whistling kite – in fact, a whistling kite actually whistling – in the Norfolk Pines on the island.   And in the distance, somewhere out of view, the elusive sea eagles, honking away like a pair of castrati ducks.  I know it’s sentimental in the light of these grim tales of the river, but I hope the birds are still there when the jet skiiers come to stay.

Midwinter lagoon

It’s past the shortest day of the year, but, in spite of her scrapes and dings, Egg the elderly wooden kayak doesn’t seem to be ready for drydock yet.  Perhaps it’s that last unseasonable whirl of autumnal warmth, caught alongside the coast in the East Australian Current, that’s keeping the sea a balmy 20 degrees.  Or perhaps it’s just the lure of still, winter water all around.

Since Egg was first laid in our driveway a year ago, I’ve been seeing Sydney differently.   Those long roundabout routes from A to B via M and Q and P, punctuated somewhere along the way by a bridge or two, suddenly make sense.  The city of roads and buildings retreats and, I feel, just out of sight on every side, the presence of water.
.

This is our backyard, encircled by the salty embrace of the Hawkesbury estuary.  But it doesn’t end here, with the secretive topography of flooded river valleys. All the way up (and down) the New South Wales coast, the shoreline is flanked by coastal lagoons. I’m not complaining, even the tiniest little bit, about all these sheltered waters.  But I’ve started to wonder what geographic accident has given a timid canoeist so much to feel grateful for.

Along with marshes and flats, coastal lagoons make up maybe 10% of the world’s seaboards, and in NSW lots of us live by them, many more than by the ocean itself. Lagoons (or wave-dominated estuaries – there are ongoing hissy-fits around these definitions) appear where low-lying plains, rather than dramatic cliffs, meet a shallow gently sloping seabed.  Usually, they are found on shores shaped mainly by waves rather than big tides, with underlying rock that crumbles nicely into beach sand not finer, silty sediment.

The more sand the better – perhaps our generous continental shelf harbours this bounty from a time when the Sydney Basin was a enormous braided river delta, like the Ganges today.  But you don’t want too much rain – lagoons are usually fed by an underwhelming little creek or even just groundwater – that doesn’t (or doesn’t often) burst through the land between waterway and ocean.

To make a lagoon*, you need a barrier to the open sea.  In the nineteenth and first part of the twentieth century, coastal geomorphologists duked it out over just how these barriers were born.  Did breaking waves make for ever-rising off-shore sand bars?  Did encroaching seas submerge coastal dunes? And then there’s the third, attractively named “spit accretion theory” (Davis and Fitzgerald, 2004).  Not, as it might sound, a creation myth where bunyips drool into puddles between the dunes; just sand clinging to rocky headlands as it is carried along the coast by the (delightfully piratical) longshore drift.

It turns out that everyone was right, at least some of the time.  Which is nice.  It’s hard to keep the heat in a scientific controversy when lots of the evidence, hidden beneath the surface of the sea in the first place, has been washed away or covered over during the last few millenia by terrestrial silt or aeolian sand.  Who could be angry with such mellifluous and frankly otherworldly-sounding geomorphologies in play?

Most lagoons have only been around for a little while, geologically speaking, formed after sea levels began to rise as glaciers melted 18,000 years ago or thereabouts. Many, like Narrabeen Lake, which we whizzed round on our bikes in the company of half the population of the North Beaches a few weeks ago, are even younger, not seven thousand years old. A blink of the eye for people who were here 50,000 years before.

Strangely, lagoons move.  Today’s surfers walk across the relics of yesterday’s drowned lakes.  Barrier beaches migrated landward, emerging from the ocean just as “marine transgressions” (that’s advancing oceans, not the naughtiness of waves) slowed.  Shaped in stable times, coastal lakes still don’t hang around for long.  This shouldn’t surprise me – I know that, despite appearances, beaches are really rivers of sand.
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If the tides were higher, if the rivers was faster or siltier, if Australia wasn’t so seismically serene, the lagoons would fill up and dry out or be washed away, and the cormorants would have to hunt elsewhere.  In fact, for all our dredging and draining, it’s happening right now.  Like life itself, coastal lagoons are a transitory phenomenon, a passing pleasure.
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But sometimes, under the fresh sand and brackish water there are older and odder things. The beautiful Myall Lakes, where we not long ago spent a glorious weekend, lie in the bed of an ancient river, separated from the sea not just by dunes that arrived ten minutes ago (okay, 2,000 years ago) but also by the Inner Barrier, deposited before the last glacial maximum and thirty times older.
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And then there’s the gyttja, something so very special it’s found nowhere else in Australia, and helps qualify Myall Lakes as a unique protected wetland.  What is it?  Well, rotting pondweed.  No, I’m underselling it: it’s up to 70cm of  “a highly mobile and organic mud that has a gelatinous appearance”, a “flocculent green–brown material” (Drew et al 2008), “an uncompacted, anoxic and sulphurous ‘ooze'” made from “the decomposition of charophytes, macrophytes, cyanobacteria and algae”.  Strangely, not so much about the ooze in the National Parks brochures.  But it’s an ooze that’s been there for, perhaps, a thousand years.

I’ve been thinking about lies beneath the surface of the water and the windblown sand.   But paddling through the Broadwater two weeks back, in a startling moment I found myself not gliding above the mysteries of quiet waterways, but surrounded, right amongst it.  A huge flock, a murmuration almost, of little black cormorants, perhaps returning from a fishing trip, passed above and on one side and on the other without a single cry but with a sound I’ve never heard before: the white noise of hundreds and hundreds of moving wings.

The sound of the midwinter lagoon, all around me.

* Be warned: there’s a chance my account of the origins of coastal lagoons is completely wrong.  After all, the New South Wales coast “has provoked many questions and various degrees of controversy” (Thom, 2010, 1238).  And perhaps it’s “premature to attempt a comprehensive analysis of coastal lagoon evolution and dynamics when so many lagoons have been so little studied” (Bird, 1994, 13). In case you want to check my workings:
References
  • Bird, Erik (1994) “Physically setting and geomorphology of Coastal lagoons”  in Kjerfve, B. (ed) Coastal Lagoon Processes, Elsevier
  • Davis, R. and Fitzgerald, D. (2004) Beaches and Coasts, Blackwell Science
  • Drew, Simon Iona Flett, Joanne Wilson,Henk Heijnis, C. Gregory Skilbeck (2008) “The trophic history Myall Lakes, NSW, Australia”  Hydrobiologia 608
  • Eyre, Bradley and Damien Maher “Structure and Function of warm temperate east Australian lagoons: implications for natural and anthropogenic changes” Coastal Lagoons: Critical Habitats of Environmental Change, dited by Michael J. Kennish, Hans W. Paerl
  •  Martin, Louis and Jose Maria Landim Dominguez (1994) “Geological history of coastal lagoons” Kjerfve, B. (ed) Coastal Lagoon Processes, Elsevier
  • Masselink, Gerhard and Hughes, Michael (2003) Introduction to Coastal processes and geomorphology, New York, Oxford University Press
  • Thom, Bruce, Hesp, Patrick, Bryant, Edward (1994) “Last glacial ‘coastal’ dunes in Eastern Australia and implications for landscape stability during the Last Glacial Maximum” Palaeogeography, Palaeoclimatology, Palaeoecology 111 (3-4)
  • Thom, Bruce (2010) “New South Wales” Eric Bird (ed) Encyclopaedia of the World’s Coastal Landforms, Springer

Happy International Year of Soils!

I’m not kidding.  The UN has declared 2015 the International Year of Soils.  And not before time.  Everyone should be preoccupied with dirt.  I know I am.  What is going in down there, under the ground? Are my veggies growing in podzol or mycelium? Hang on, that’s soil profiles in Minecraft, not in Berowra.

The CSIRO’s recently released Soil and Landscape Grid with its 3 dimensional digital soil attribute maps could resolve most Australian gardeners’ soil questions. In case you were wondering how these maps were developed, let me put you out of your misery:

“The spatial modeling was performed using decision trees with piecewise linear models and kriging of residuals. Fifty environmental covariates that represent climate, biota, terrain, and soil and parent material were used in the modeling. Uncertainty was derived using a bootstrap (Monte Carlo-type) approach to derive for each pixel a probability density function (pdf), from which we derived 90% confidence limits”

More kriging of residuals, I say!

Gags aside, this free online resource shows why Australia needs publicly funded science and why sacking researchers in the CSIRO to bankroll Gina Rinehart’s tax breaks is a major error (if you need more persuading, CSIRO scientists also invented WiFi, Aerogard, the permanent pleat, and the word petrichor, which describes the lovely smell of damp earth after rain).

After reading about the rocks in our neck of the woods, however, I’m not sure we are best placed to fully exploit the sophisticated visualising technologies of the Soil and Landscape Grid.  The geology around here is pretty danged boring. Other than the odd lens of shale, mostly on the ridge-tops (that is, under roads and houses) it’s Hawkesbury sandstone all the way down, 40 million years and 270 metres of it.  Or at least, all the way down to Berowra Creek where there’s an outcrop of more fertile Narrabeen Group of shales, sandstone and clays here and there.

Of course, we’re not alone in our preposterously deep beds of sandstone.  They’re on display in the Blue Mountains too, though with a few more layers clay and basalt intrusions to break up the tedium.

The humungous quantities of sandstone across a swathe of the Sydney Basin makes my sentimentality about the disappearing rock faces along the new railway cuttings of the Northern Line even more absurd.  After reading about the good exposures of Ashfield Shale between Hornsbury and Beecroft,  I’ve become a tiny bit obsessed with capturing the freshly exposed slices of Sydney Basin geology as they are revealed by the diggers and before they’re covered with nasty grey concrete.  Wordsworth was mortified by the ugliness of railway cuttings slashing their way through the nineteenth century British countryside.  Here am I mourning for disappearing railway cuttings, a slice of geological time revealed and then lost again.

Perhaps I should stop grieving the lost glories of the Pennant Hills trackwork and spend more time worrying about what my garden might be doing to the “quartz rich, nutrient poor” soils of Berowra.

My snake beans are kinda sallow – I reckon they need a side serve of well-rotted chicken manure.  But even as I contemplate emptying the compost tumbler, I can’t help but fret about where my vegetable garden sits, perched above the national park with its “rich and distinctive assemblage of species that thrive on poor soils” , “60-80 different plant species growing together on an area half the size of an average house block” (Benson, Howell, McDougall, 1996, 24-5).  Benson and Howell in their fascinating Taken for Granted: the bushland of Sydney and its suburbs (Kangaroo Press/Royal Botanic Gardens, 1990) mourn:

 “much of Hornsby’s rugged sandstone terrain remained undisturbed until after World War III when the increasing availability of the car and improved building technology made steeper, more remote sites available for housing.  As a result, bushland on ridge-tops and upper slopes has been totally destroyed, the bush remaining only where it is virtually impossible to built, and along steep gullies which have become drainage lines.  Virtually very catchment system includes some suburban development, stormwater run-off from which contains silt and nutrients.  These promote weed invasion of sandstone gullies… in newer areas such at Mt Colah and Berowra [the] invasion is beginning, and the consequences appear inevitable” (108)

And that’s us, in our mid-century twentieth century house, teetering on a steep slope in a fold of the hillside you might otherwise call a creek bed.  My painstakingly-made hot compost, my organic sugarcane mulch, the poo from my beloved chickens, all building nitrogen, carbon, phosphorus rich earth – garden alchemy.  I’m creating an anthroposol – a human made soil – and I’m not entirely sure that’s a good thing.

As a homage to the UN’s declaration, I’ve stared in a  incomprehending way at a schematic cross-section of Hawkesbury soils, I’ve thought long and hard about our B horizon (by staring even longer at this quite marvellous online introduction to soil classification – thanks again, CSIRO) and I’ve double-checked Minecraft’s definition of “podzolic” with the kids but I’m not sure how far it’s got me.

Maybe this is the chthonic thinking – thinking about the soil and the communities, plant and animal that grow from it – that my friend Kate urges us all to do in her fab blog about the Armidale Community Garden, but it’s not so much grounded me as taken me directly to Hades via the Field of Punishment.  This is a special special place of suffering for people who long to understand rocks and dirt but can never remember whether the Devonian comes before or after the Carboniferous, no matter how many times they read David Johnson’s splendid Geology of Australia.  And that’s without wrestling with the geopolitics of topsoil loss or the impact of international agribusiness on pesticide residues or the links between soil, country and indigenous chlthonic law

The only solution to this torment, I feel, is another variant of subterranean thinking: that sense of mindfulness I get sitting in a darkened vehicle with a swag of empty shopping bags, gazing tranquilly at the carefully preserved, sandstone rock exposures in the underground car park of Berowra Coles.

Happy International Year of Soils everyone!

Superfood of the Undead

In the light of the Berowra Potato Famine of 2014, I am grateful that the obituary I gave for the kale some months ago was premature.

People may say they grow kale because of its alleged status as a superfood, but I know the truth.  People grow it because it’s impossible to kill.  Attacked by aphids, gone to seed, garrotted daily by the garden hose, baked in the hottest spring on record and scarified on a regular basis by the vicious claws of visiting brush turkeys –  after all that, my kale plants have felt the need for a little lie down.

However, having risen from the grave once, they won’t just won’t lay down and die.  Those leaves keep right on coming, whatever I throw at them.  Not great big fancy leaves, good for stuffing with, say, quinoa and chick peas. More the slightly stunted, hard living leaves you might expect to be produced by the once-definitive vegetable of a country famous for its disdain for vegetables.  In dark and gloomy pre-industrial Scotland, kale was such a staple that the veggie patch was called a “kailyard”. and by extension, the evening meal, “kail”.   Any green that can crush the neep in the death-match for vegetable supremacy on the Scots dinner plate is not to be trifled with (boom boom).

In the light of this backstory, I’m starting to wonder about the untimely demise of my tatties.  The flea beetles are in the frame for the execution of my potatoes, but all the while, the kale lay nearby… unnoticed… waiting… Could it be that my zombie kale has vengefully fed on the life-spirit of the blighted potato, colonial pretender to the Scottish vegetable crown?