David Vass

How Blue is Your River?

2021 Zealandia Te Māra a Tāne Essay Prize: 2nd place winner.


Mata-au/Clutha River.         Before.

As human beings, we seem to have a deep-rooted desire to connect with ‘real’ nature; it could easily be argued that we need to. In the world we inhabit though, it is hard to find somewhere with the level of connection we crave, because we mostly find ourselves interacting with the bits of the natural world that are reduced in quality, degraded by our own actions. There are some relatively pristine places left—mostly in the backcountry and harder to access—but what about those places to be found right on our doorstep? Another way to find what our relationship to nature could be, might be to look a little differently at those places, and at what form that connection could take.


Thick dust pops into the air, dirtying my feet as I pad barefoot along the riverside track. The dryness and heat makes the deep cool of the river increasingly inviting and I savour the heat as an anticipation, the wetsuit and fins on my back slapping the back of my legs as I walk.

I start from the rounded pebbles at the outlet, where the deep waters of the lake begin their slide towards the sea. The first moments of the dive are always ones of adjustment; feeling the water seep into the wetsuit and the change from moving yourself to being moved by something other—the river. This is my favourite way to descend the Clutha; a mask for looking, a wetsuit for warmth and weighted to achieve a neutral buoyancy, gliding with the current. It is an easy approximation of flying—a liquid, crystal, sort of flying. Staying close to the bottom, I weave between large boulders with arms outstretched; in swift places a guided projectile, in others peacefully drifting in the current.

The first part of the drift is over fine gravel banks, out from the carpark. There are always fish through this section. Then there is a long section of slow water, a good place to get one’s breath-holding sorted before the rapids. There are fish here too, not usually big, but bright, fat and easily alarmed for it is wide open and they have little shelter. From near the bottom the surface is a distant dappled mirror and you are surrounded by the deep, aquamarine colour of water. When the sun is shining, beams of sunlight burn through the clarity. With cloud cover, the feeling is more sombre. Either way, down here, this beginning of a river is very peaceful.

The sensation of leaving the calm section for the first rapid is of being poured from a jug; from a smooth laminar flow to a turbulent and boisterous world, diving into the unseen-but-felt eddies behind boulders, feeling your body bend and fold in the turbulence. There is a thrill in staying close to the bottom of the river and feeling the rush of the terrain sweeping past.

After the first couple of rapids, there is a long run at the end of which a large rock sits mid-river. At the right river level there is enough water to glide straight over the rock, duck into a forward roll and go straight to the bottom. There is a liquid bubble of calm behind the boulder, a space to sit quietly on the sandy floor, watching bubbles form and vanish, sand particles lift and fall in a mesmeric dance. Back on the surface there is a good wave for body surfing, where I manage to spend a few seconds before being pulled off by the quick current, spinning vertically in the whirlies along the edge of the current-line. Several times I have spent time here, surfing, spinning and playing in the bright liquid world behind the rock, laughing, with the river all around me.

Downstream from here, the current runs swift and even over rounded stones of white quartz and pale schist, fallen from the sloping wall of Deans Bank. The swift flow takes you through the sunken branches of a long-fallen willow, a quick thrill if you want it. At the end of this run, the bottom falls quickly away into the depths of the big pool at the campground and it is possible to duck-dive out of the current into the drop-off at the head of the pool. More likely though, you’ll glide over the cluster of trout hovering beneath the current tongue, often twenty or more, and be whisked into the centre of the pool. A dive to the bottom here takes you deep into the heart of the river. It is a contemplative place to be, within the blueness of the pool, a giant otherworldly fishbowl.

The exit to this pool is swift and shallow, so shallow that you feel the current lifting and bouncing off each of the multicoloured rocks as you glide over them, inches from your mask, hoping for no collisions, thinking about your knees. Straight after this is the local swimming hole on your right, where old George used to sit up the top and throw bread into the pool, getting it boiling with trout. After dark, with no-one watching, the river provided for George too. It is good to get out here, just before the bridge, not just because you are always cold by now. A few hundred metres downstream the Cardrona River enters the Clutha and adjacent to this, the processed sewage of Wānaka township does too. From here on down the bottom of the river sports a thick black band of algal sludge.

But here at the Albert Town Bridge, leaning on the rail and looking into the river, what you see, apart from nearly always a few trout and once a very large eel, is the colour of the stones. Some are orangey, some dark, but many are white, and over these the only colour to be seen is a pale glowing blue, that takes a depth of it to see at all. It is the colour of water itself and nothing more. 


Mata-au/Clutha River.         After.

So, I know the river pretty well and I could tell you plenty about it. Mainly though, I can tell you this: that the river is no longer blue. It still looks blue to most people—visitors exclaim how lucky I am to live on its banks, and tourism websites proclaim its beauty—but I no longer dive the river and I no longer fish it. My heart is broken.

The first time I noticed the small spots of algae on the riverbed stones was in 2004, at the end of summer. I knew what it was and I knew it grew fast but I couldn’t believe it when, come the next spring, standing on the tree stump at the swimming hole, psyching up for the first chilly plunge of the season, I looked into the river to see the bottom covered, bank to bank, with a thick mat of the stuff.

Rock snot, Didymosphenia geminata—‘didymo’—has pretty much killed the riches of the Clutha. A drift dive of the outlet section reveals an ecological desert below the surface, a near-continuous cover of didymo over the riverbed, rippling and waving in an almost pretty way in the clear water. Nothing that a trout eats lives in the mat of algae—if on your dive you saw half a dozen fish it would be a good day; I’ve seen none a couple of times now. The millions of invertebrates that fed them, that covered the riverbed, are mostly gone, replaced by small wormy things. The ‘river moths’ that covered the night-time windows of Albert Town are a thing of the past.

The most unsightly time of year is autumn. The lower river flows expose the banks of snot that have bloomed through the summer so they die in the sunlight, turning into something like egg box cardboard spread over the rocks. As the river rises again with the first winter rains, this dead mat re-hydrates and becomes heavy and waterlogged, breaking off and rolling downstream in sheep-fleece skeins; dead, pale and poisonous looking. After last year’s flood the river-edge trees were festooned with streamers of rock snot. People rang the council to report a sewage spill, the rank lengths looking just like wadges of wet toilet paper.

Any summer day spent on the Albert Town Bridge now you’ll see clumps that have broken off, drifting downstream in the current. Count yourself lucky if you see a fish. What you won’t see, leaning on the rail, is the colour of the stones. Or just the colour of water. Blue over brown is a kind of green.


Rock snot though, is just the latest signal of the decline of the Clutha; another symptom of our lack of care. Other burdens have been foisted on the river in the past. Where previously the starry backs of galaxiids rose in countless numbers along the banks of the Mata-au, and tuna/eels swam its depths, trout have taken over. To be sure, trout are a glorious fish—they look beautiful and taste good—but they have predated and competed their way to ecologic dominance over native populations.

Heavy industry has weighed in too. The dams in the lower river drowned more than powerful rapids—they have also separated the native fish from the rest of their life cycle and dampened the cleansing power of floods. The river-shaped gorges of a previous time lie buried under stagnations of still water and accumulations of silt. The life force—the wairua—of the river, has been altered forever. More recently, in small ways, we have made improvements; at least the sewage from Wānaka goes elsewhere. Upstream though, the source of the river’s water is no longer so pristine.  ‘Lake snow’, the stillwater version of didymo, fills the water column of the lake, clogs the tap filters in town, and the lines of anglers.


Most people will never notice this slide towards mediocrity, or worse, but some will. They will be anglers, the older residents of Albert Town, or the odd drift diver—those who spend time with the river. I can still remember the river around Cromwell; the terraces of apricot orchards and stone huts, the steep rock walls dropping into the swirling (and blue!) depths. Whenever I drive the now anodyne road above the hydro lake, I try to remember how it was before the dam, but I find it harder than I used to. What I don’t remember is what it looked like before that; the golden grassy hills look beautiful enough now, but they were once covered in forests and roamed by animals, many that are now extinct.

We lose perspective through the passing of time, but what we really lose is our environment.  The quality of our natural world is continually compromised because we simply don’t remember how it should be. We accept that the rivers we have left are no longer blue, because they look blue enough. We accept the degradation of our world because we forget—both within our own lifetimes, and generationally. The yardstick of quality gets shorter all the time.

It’s hard not to feel overwhelmed. How can we—as normal, fallible human beings—not forget?  It seems such a big ask, so hard to achieve. I have now moved away to a bigger city. I no longer see the river, have a feel for its moods and habits. It’s harder to care about what happens there. I too am forgetting the river, as the people I share the city with have largely forgotten the forests and animals. I am less connected. Where to start?


Ōpāwaho/Heathcote River.              Today.

Nature doesn’t forget, but it does evolve; the Clutha will come back somehow. It may not be as it was or how we might like it to be, but it will endure; nature will have its way. As people, we too will have to evolve, and look at things a little differently.

Just down the road, in my new town, I have found another river on my doorstep. The Ōpāwaho/Heathcote is dirtier, soupier—more ‘urban’—to be sure, but is again, another world on my doorstep. It probably used to be blue as well. I find myself sitting by my new river, peering into the murky water, trying to sense what is in there. I imagine swimming and shudder, but people used to, and not that long ago.

“The mullet’ll be up with the tide shortly,” a voice says over my shoulder, “comin’ in to feed on the whitebait.”

I look again at the river. It starts to make a little more sense, flowing backwards. The character talking to me also looks distinctly urban, wearing baggy track pants and scuffed old basketball shoes, but he seems to know his stuff. He sits on the bench seat next to me and we get to talking; eels, the recent flood, the work that’s been done along the bank recently, and other less savoury stories of urban development and industrial waste disposal.

He seems an unlikely saviour, but if I was a river, I’d like him on my side. His connection has come through working along the banks of the river, observing its everyday rituals. He tells me of community working groups and getting others involved. It sounds like they’re making progress.  The seemingly irresistible degradation of this river is being slowed down, reversed even.

He gets up to leave. “The council are lookin’ for ideas, talkin’ about a track. There’s a meeting down the hall on Tuesday at 7 o’clock. Oh, and a planting day on Saturday.” He walks off with a sly grin on his face; “Wanna come?”

My curiosity is piqued. I scratch the surface of the area’s history on the internet. It seems the river area was formerly a network of waterways, and a resting place for travellers. There was a small village, and the low-lying area around was a renowned food gathering site for Ngāi Tahu, rich in fish and birds. Today the trees are mostly exotics, but it is still a place of rest—each weekend people stroll the banks, and walk their dogs. Some even paddle canoes. As I read, I feel myself being drawn into not just the history, but a vision for the future, one that might not be that different to the past. It might not be remembering, but it’s a start to not forgetting.

I cast my mind back to drift-diving the Mata-au, to being amongst the swirling blue currents, surrounded by the life-force of the river. I won’t be swimming anytime soon in the Ōpāwaho, but I can admire its tenacity, its capacity to regenerate, its particular wairua. This river needs help to come back though, and maybe this is where that sense of connection is to be found; in the first turn of the spade, in the telling of a story. Perhaps I’ll make it to that council meeting down the hall.





David Vass

David Vass is a recovering mountaineer. He has recently come down from the mountains to engage more with the world of people and do some writing.