The Palimpsest of Rivers
Question: what do these six English chalk-streams have in common and what makes this one New Zealand spring-creek so different?
Answer: all the chalk streams have been dredged and the New Zealand river has not. Even in the more idyllic looking images of the English rivers, where the water is clear and green weeds billow in the flow, it is possible to discern how the rivers have been deeply etched into the landscape, when once, like the New Zealand stream, they would have flowed brim-full.
This then is THE BIG ISSUE when it comes to the health of UK chalk-streams. Abstraction adds insult to this injury, combining to form the perfect storm of river degradation. On Tuesday I drove to Ipswich to say as much to the Area of Outstanding Natural Beauty delegates at their annual Landscapes for Life conference and I have copied my talk below for those who are interested to read it.
We are at an exciting point in history, with funding available for river restoration at a scale no-one quite dreamt of in the early years: this presents us with great opportunities, matched all the way by great challenges.
“Not long after I had finished writing my book Silt Road – The Story of a Lost River in which I tried to describe the layered histories that built one after the other to create the suburban landscape of a little Buckinghamshire chalk-stream called the River Wye, I started on another project: a Water Framework Directive catchment plan for a Norfolk chalk stream, the River Nar: this time I was writing a summary of the geography of the river, of the issues that were holding back its ecological condition, abstraction say, or the extent to which the channel had been modified, all aimed at a timetabled plan for its ‘restoration’.
The two pieces of work couldn’t have been more different, except that they each described a river. And yet, though they came at this common subject from different perspectives and for different reasons, the book of nature writing and the report for WWF both asked more or less the same questions:
• how in this overcrowded and much altered landscape do we give rivers the room they need to express their true nature?
• and what exactly do we mean by ‘restoration’, what wilderness or man-made state do we aspire to?
As part of the publicity surrounding the book I was asked to do a Q and A interview for a freebie city newspaper. The questions demanded careful answers, in one of which I used the word ‘palimpsest’. When the interview came out at least three people emailed or texted to congratulate me for getting that word into Metro. This was a little unfair on Metro, I thought, but perhaps I had used it in that way people do tend to use so called ‘clever’ words: as if it had just fallen off the tongue and I’d known what it meant for ever. In fact it was a word I’d read here and there over the years, always guessing its meaning by context, until finally I’d looked it up, and realised that it was a very good word to describe exactly what I was interested in.
And so I used it … and thousands of Londoners thought, “how pretentious!”.
But it is a good word, exactly the right word in fact, to describe the phenomenon that leads to those two questions. Palimpsest comes from the Greek palin ‘again’ and psestos ‘rubbed smooth’ and it describes a manuscript on which the original writing has been rubbed out to make room for later writing, but where the traces of the earlier text remain, or a thing – like a building say – much altered, but still bearing traces of its original form.
And so it also describes, rather brilliantly, the British landscape: a thing much altered many times over, bearing not only traces of its original form but of all the subsequent forms, each super-imposed layer upon layer, shaped by what came before, shaping what came after.
Looked at like this, the landscape and its rivers as palimpsest, what on earth do we mean by river restoration? Which of those former states do we aspire to? And if we are hoping to create some kind of proto-wilderness, what about all these other layers in our landscape? What of the medieval channels to feed carp ponds, for example, or those diversions dug to facilitate the construction of ancient priories? What of water-meadows or mill streams: doesn’t each layer in the landscape form its own discrete and complex mix of history and ecology?
There is an ancient water-meadow at Ovington in Hampshire, on the upper River Itchen, which has not been altered or improved, has seen no fertiliser and no plough and only light grazing for the past three hundred years: it is of historical interest but it is one of the richest ecological sites on the whole river: in one part this is because it is a man-made water-meadow, and in another because it has been left alone since it became one. It is a preservation of one tier of that palimpsest: the era of water-meadows.
Reaching back further in time the functioning mill-leat and flood channel must once have created a modified ecology comparable to water-meadows. The languorous flow of the leat, the deep, swirling mill-pool, the faster flow below and the original, meandering river managed as a relief channel: deep water, fast water, slow water, shallow water – a rich diversity of habitat created as a bi-product of the milling process.
Most chalk streams are punctuated by as many mills as their gradient and flow allowed and have been for many centuries. And yet now the mills present a more ambiguous legacy: stagnant leats are filled with silt that we daren’t wash downstream and the relief channels have been left to choke up and dry out. The era of milling is of unarguable historical interest, but the unused milling structures left behind often impoverish habitat, when once they might have enriched it.
If the original parchment of our chalk rivers was the diverse, natural ecology of the landscape left behind by retreating glaciers and evolved by a warming world over the millennia and centuries since, then each subsequent imprint has subtly or greatly altered that ecology. Many changes have been benign. And the influence of some others has changed over time. Certainly until the mid-Twentieth century and notwithstanding the mills and water-meadows, estate lakes and ornamental cascades, the ecological diversity of our chalk rivers had not been greatly compromised, even if it had been subtly and variously changed. Waterside land was dedicated either to summer pasture, or hay-making, or being too unproductive to farm and difficult to drain was left as wet woodland and marsh.
But two recent imprints have much more drastically modified the gently nuanced palimpsest we had inherited by the middle of the last century.
In the decades following the Second World War a drive towards agricultural intensification and efficiency almost erased the wetlands of southern England. Farmers were subsidised per acre ‘in production’ or ‘per head’ of livestock and through the Fifties, Sixties and Seventies diggers became the new megafauna of the landscape; chalk-streams were lost behind banks of spoil, quite literally turned on their heads. Through dredging and channelisation, through a wringing out of the wetlands, water-meadows were modified to take higher densities of livestock, or to grow wheat, and vast tracts of formerly uncultivated land were brought into production.
The entrenched chalk-stream now lost in deep canyons has been doubly hit by abstraction: bloated and uniform channels carry half their natural flows. Sometimes they dry up altogether. A moving essay The Passing of a River published in Blackwoods Magazine in 1947 describes how the upper few miles of the River Kennet were dried by abstraction after only one, small public water supply pump had been installed.
During dry summers in Norfolk flows on the River Nar are cut in half by abstraction. And the situation is getting worse year after year as actual abstraction moves ever closer to licensed abstraction. If those two lines ever meet there won’t be a river in summertime.
But these dredged and abstracted rivers also represent a tier of the palimpsest. And so the ‘restoration’ of such a complicated canvas deserves as much consideration as the restoration of an old painting or listed building. What are we restoring away from and what towards? And what is it okay to erase in the act of re-creation?
There is a danger, for example, that in restoring to rivers the ecological richness they have lost through dredging and abstraction, we erase previous more benign historical imprints.
There is a danger also that we replace them with arbitrary or subjective interpretations of a more desirable state, only to realise with hindsight that what we considered ‘restoration’ was just another tier of modification – and an inelegant one at that.
Think for example of the kinds of constructions we sometimes impose on rivers in the name of restoration: orchestrated, tidy groupings of woody debris; gravel riffles that rise and fall at neat angles built of graded layers of stone; re-meandered curves that are unconvincingly uniform: graded banks and revetments that run from meadow to river at an even slant. Constructions that suit design software and bills of measures and flood-risk assessment pro-forma, but not necessarily rivers.
A river is a live and dynamic and self-managing entity. So, what is it that we should aim to overcome in the act of restoration? The answer must be, or ought to be, only the man-made limit to that dynamism and capacity for self-management. The act of restoration ought to begin and end with that aspiration: not so much an imposition of structure, as an unbridling of process.
Dredging and abstraction are the two intertwined modifications that have between them imprisoned our chalk rivers like never before, that have divorced them from process. Chalk-streams are very low energy systems which evolved over millennia inside valleys carved by forces which have long since retreated from our landscape. A chalk-stream is therefore particularly vulnerable to modification, because this side of another ice-age it will never have the energy to overcome, to erase that imposition.
This is why we have to be especially careful with restoration structures.
But this is also why the dredged river is locked in and will never escape, and why of all the modifications visited on chalk-streams over the centuries the era of dredging and abstraction was … and still is … by the far the most damaging. A dredged chalk-stream of diminished flows can only rise and fall within the confines of the man-made channel. It cannot deposit where it needs to, it cannot erode where it needs to: its riparian and in-stream plant community is impoverished and so are its flows and so is its ecology.
I have been lucky enough to see at first hand unmodified spring-fed streams in other much less busy parts of the world: in New Zealand, Patagonia, Iceland, Montana and Bhutan. What has always struck me about these rivers and what they have in common with the comparatively un-spoilt parts of chalk streams I have seen in England is a very simple spatial relationship between water level and ground level. Put simply they have never been dredged and because of this they function like a river. A natural chalk-stream flows close to bank height and in that way it relates to the land which surrounds it. That close relationship – call it ‘connectivity’ – creates the riparian community that allows a river to breathe: to expand in winter, shrink in summer, to meander, to erode and deposit: to be in other words the live, dynamic, self-managing system that we ought to want at the heart of our landscape. In chalk-stream restoration therefore I strongly believe we should most of all look to ways of reuniting the stream with a living riparian margin.
If we restore that connectivity, we will restore process. If we restore process, the river will restore itself.
3 Responses to “The Palimpsest of Rivers”
Lovely piece Charles, an informative read. When those ‘two lines cross’ I feel it will be like unplugging the life support in an IC Unit.
Yes – ‘A river is a live & dynamic & self-managing entity’. Rewilding it means rewilding its geodiversity. As you say, it’s about restoring process…
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