Tag: chalk streams

Tarrant update 3 – Known knowns, known unknowns and unknown unknowns.

Posted in UncategorizedTagged , Leave a comment

A fascinating comment was recently added to my post The Slow Death of a Chalk Stream. Nick Walton – a hydrogeologist with 50 years experience – wrote: 

“Hydrological/hydraulic models can only ever approximate reality, and depend upon a wealth of assumptions and averaged, default and chosen input parameters, together with a few hard, but time-limited data points (mostly fairly ‘recent’ borehole, spring and river data). Whilst this can get close enough to reality for practical / operational purposes in more homogeneous hydraulic media, in the case of the infinitely variable and unknowably complex 4-dimensional hydraulic pathways within the Chalk aquifer, the reliability of the model outputs depend upon their achieving an approximation to observed reality at just a few observation points, leaving the vast majority of the aquifer, in all four dimensions, untested and potentially quite different from expected modelled results.”

Given the above, said Nick, historical evidence, empirical data, local knowledge and some hydrological common sense are worth a lot and shouldn’t be dismissed. 

Those four things are exactly what the River Tarrant Protection Society report contains. The RTPS is saying that when all the evidence is taken in the round the case is strong enough to justify further, detailed and truly independent investigation. 

This shouldn’t be a debate about whether the Wessex Basin Model is more sophisticated than the CSF modelling. It clearly is. 

The issue is whether the confidence placed in the Wessex reports conclusions is justified, given the limitations of the underlying data, the acknowledged uncertainties in conceptual understanding, and the internal inconsistencies in model performance across the Pimperne and Tarrant catchments and beyond to the edge of the Stour. 

Data from an impacted system

All models are limited by the quality of the data that is fed into them — and here the data are limited and impacted. The Wessex model is built on:

  • groundwater level records (largely post-1970),
  • short-term stream flow gauging with spot meters (primarily 2015–2017)
  • short-term targeted pumping and switch-off tests,
  • a system that has been subject to decades of abstraction.

In other words, the model is based on data extracted from a system that is already altered from its natural state. 

Without continuous flow records prior to the 1970s, and without direct measurements of groundwater–surface water interactions before large-scale abstraction, surely historical and qualitative evidence becomes more, not less, important? And yet it is largely excluded from the formal assessment.

Of course, Jane Dottridge wasn’t commissioned to comment on this other evidence. She nevertheless described it as “anecdotal”. I don’t think that’s fair. Anecdotal refers to an account or short narrative that is subjective, unreliable, or hearsay. Mapped Domesday mills are not anecdotal evidence.

Pimperne calibration

As to the models: Jane critiqued the one-dimensional simplicity of the CSF conceptual model. However, in spite of its attempts to capture the more complex reality, there is still uncertainty and assumption in the Wessex model, especially around the Pimperne–Tarrant interfluve. 

Jane does highlight this: “the Pimperne calibration is not very good, with a very smooth modelled recession in contrast to the marked break in slope of the observations. Some of the gauges on the middle Tarrant (Rushton, Preston Farm) also show the same feature” 

But she makes little of it. In the next paragraph Jane writes: “The conclusions appear to be justified based on the evidence presented in the report”

I don’t follow that logic. To recap, the conclusions of the report are:

  • Tarrant: only the abstraction pump in the valley (Stubhampton) is relevant to flows in the Tarrant. The stream is negligibly impacted by this abstraction “along the perennial reach” * and the ecology is not adversely impacted.
  • Pimperne: the abstraction at Black Lane does not impact flows in the Pimperne.

That is a very clear no impact statement given: 

  • The calibration is poor in the Pimperne and the lower Tarrant. 
  • The Black Lane abstraction is a high % of the catchment recharge. 
  • The groundwater boundary is modelled as fixed with no impact on the neighbouring Tarrant.

Surely the mismatch between the strength of no impact conclusions and the poor calibration warrants a furrowed brow. 

* This is a variation on a rhetorical ploy I’ve seen before: if a stream is dry then abstraction is ipso facto not impacting the stream. It’s also evidence of my point about how the impacted state can become the new baseline. The RTPS contends that the lower river is naturally perennial.

Known knowns, known unknowns and unknown unknowns.

The Wessex report presents a conceptual model strategically refined by fieldwork that included stream-bed surveys, weekly observations and spot-flow measurements, new boreholes to investigate the interfluve, switch-off and pumping tests. 

Accordingly, the model was refined to simulate lower transmissivity beneath interfluves, higher transmissivity in valley bottoms and the introduction of “unmapped faults” in the chalk – horizontal flow barriers – to improve calibration.

Surely these iterative refinements highlight, rather than resolve, the uncertainty? The interfluve behaviour was not predicted by earlier model versions, new borehole data required significant reinterpretation of the system and the fault-line is partly imposed through model structure, inferred  – because the river dries – rather than directly observed in the geology.

The cornerstone conclusion ref the Tarrant — that abstractions outside the catchment have no impact — depends on the assumption of limited cross-interfluve connectivity. And yet groundwater catchments are known to shift with hydraulic gradients and Jane’s review confirms that groundwater boundaries can and often do vary over time and with rising and falling groundwater levels. If they do this, they can also vary because of abstraction pressure. 

A central element of the Wessex argument is that switch-off and pumping tests define what they call “zones of influence” of abstractions and that impacts are therefore spatially limited.

This interpretation is not supported by general hydrogeological principles. Why does it pass, unchallenged?

Short-duration tests reveal immediate, local drawdown responses but do not capture longer-term system adjustment. They don’t capture the delayed propagation of pressure changes, the redistribution of groundwater flow paths, or slowly accreting capture from inter-connected water bodies. 

The absence of observed drawdown at a location during a short test simply cannot be taken as evidence of no long-term hydrological impact.

Pick’n’mix

There is also evidence of expedient selectivity in the Wessex report and even Jane points this out. Where the Wessex model performs reasonably well – the Tarrant – it is used to support conclusions. Where it performs poorly – the Pimperne – then alternative methods are used: pump tests and empirical observations.

This pick’n’mix kind of undermines confidence in the whole thing surely? The analytical method is not consistent across the whole piece. 

John’s CSF model may be pilloried for its simplicity, but at least it treats the whole study area in the same way. The Wessex Water approach ought to weaken the Environment Agency’s confidence in the system-wide conclusions, particularly those relating to this cross-catchment impacts we insist are plausible but which Wessex Water hotly denies.

What about 2017?

I’ve already underlined the coincidence between a long-term shut down 2016 to 2017 of the Black Lane pump in the neighbouring Pimperne valley and the fact that the summer of 2017 was the one year in the past ten that the lower Tarrant did not dry. This is such good evidence that the Black Lane pump may well be having an impact on the Tarrant, or the Black Lane and Shapwick pumps in tandem, especially when one remembers that the spring of 2017 was bad for chalk streams. That was the year that I took photographs of drying streams all round London, the Ver, Chess, Misbourne, Beane, Rib, Ash and others.

The year the Chess looked like this, the River Tarrant kept flowing.

Wessex Water has an answer: they claim that late summer rain prevented the Tarrant from drying when it was otherwise on course to. I put this to John Lawson and he went away to look at the rainfall figures over a longer time-series, to see if this late summer rain was an anomaly that plausibly did make the difference.

As you can see, the summers of 2015, 2021 and 2023 were similarly wet or wetter than 2017, but the river still dried. Whereas the the preceding October 2016 to March 2017 was unusually dry and that’s what usually determines flows in the following summer.

In summary

There is a mismatch between limited range of data (no consistent, long-term flow gauging), incomplete understanding of the aquifer, poor calibration in the modelling and confidence in the conclusions.

The purpose of highlighting these issues is not to suggest that “we are right and Wessex Water and the Environment Agency are wrong”. Instead it is to demonstrate that:

  • alternative models produce plausible results which do suggest an abstraction impact,
  • key assumptions (e.g. fixed catchment boundaries, limited zones of influence) are not definitively proven,
  • the current evidence base does not support a strong “no impact” conclusion.

Given all the above surely it would be prudent to treat the current findings as provisional rather than definitive and look for a more robust truly independent investigation, with scope not limited to model comparison.

Let’s not forget, this stream is used for spawning by Atlantic salmon. The stream may not be as protected as the Bourne and Wylye, but the salmon is. These fish are genetically unique to chalk streams and the Stour’s population of these fish must be the most endangered stock of all.

Oh and just one more thing …

Underlining the mismatch between what we know and confidence in conclusions, it is worth addicting that recent research into the Chalk aquifer by Andy Farrant and others at the BGS has highlighted the greater-than-previously-recognised role of karstic dissolution features and preferential flow pathways in chalk. These can provide localised areas of enhanced permeability that are not necessarily captured in regional groundwater models. Hydraulic connectivity may well occur along pathways that are not predicted by averaged aquifer properties or detected by limited observation boreholes. This must be relevant where abstraction alters hydraulic gradients, potentially activating or enhancing flow along such pathways?

Sure, this does not demonstrate that such connections exist between the Pimperne and Tarrant catchments, it does underline the uncertainty associated with assuming that lower-transmissivity interfluves act as hard hydraulic boundaries.

Just saying …

Tarrant update 2 – In defence of simplicity

Posted in UncategorizedTagged , 1 Comment

As this photo of an exposed chalk face shows, chalk aquifers are pretty darn complex. But that doesn’t mean simple models can’t tell us useful things about their fundamental behaviour or that sophisticated models are, per se, more accurate.

In my last post I questioned why the Environment Agency confined its review of the River Tarrant Protection Society (RTPS) report to a comparison between two modelling approaches.

I argued that the Chalk Streams First (CSF) model—a simple, lumped parameter model—was never intended to replace the more complex 3-D model used by Wessex Water, but rather to highlight uncertainty. Several hydrogeologists, including the independent reviewer, have previously suggested that such approaches can be used in a complementary, tiered way, with monitoring data providing essential context.

In that light, it makes little sense to treat this as a modelling contest in which the limitations of one approach invalidate its findings. Model outputs should be interpreted alongside other lines of evidence.

The independent review compared:

  • the Wessex Water Middle Stour report (the official position), and
  • the RTPS report on low flows and drying

with a focus on hydrogeological data and modelling.

In this post I consider that comparison in the light of Jane Dottridge’s review (attached to my previous post), focusing specifically on the conceptual and methodological validity of the CSF model.

Assessment versus indicator

Jane was asked to comment on the validity of the RTPS findings on abstraction impacts, and to consider the Wessex report by comparison. She concluded that the CSF model does not “provide a more reliable assessment of abstraction impacts than the Wessex model”.

However, the RTPS report did not claim to provide a more reliable assessment, but rather a more reliable indicator. That distinction matters. An assessment implies a definitive evaluation; an indicator signals a relationship or pattern without claiming certainty.

The CSF model was presented as part of a broader evidential framework. Its outputs, taken together with other observations, were used to question the certainty of Wessex Water’s conclusions. Judging it as if it were intended to deliver a standalone assessment risks setting up a straw-man comparison.

The conceptual model

Jane states that the CSF model is highly simplified and suggests first of all that it has no conceptual basis, then later that it lacks a sound conceptual basis. There is some ambiguity here: whether no conceptual model exists, or whether the one used is considered inadequate.

In practice, the CSF model is based on a clearly defined—if simple—conceptual model. It assumes:

  • a fixed groundwater catchment based on topography
  • uniform transmissivity
  • a broadly synchronous rise and fall in groundwater levels
  • a distributed pattern of spring discharge across the valley

These are simplifications of a complex system. In reality, groundwater catchments shift, transmissivity varies, and flow processes are spatially heterogeneous. But the question is not whether the model captures every detail—it does not—but whether it is appropriate for its intended purpose.

There is ample precedent in groundwater science for simplified conceptual models, particularly where the aim is to identify dominant controls or test the plausibility of observed relationships. 

Model complexity should be proportionate to the question being asked.

Empirical relationship between groundwater and flow

The CSF approach is grounded in an empirical observation: that groundwater level and streamflow are closely correlated in chalk streams.

John Lawson has shown – using historical data – that, within relatively tight bounds, when groundwater levels are at a given elevation, streamflows fall within a given range. This close relationship appears to hold across long time series and across multiple different chalk stream catchments. John has looked in detail at the Rivers Kennet, Og, Misbourne, Chess, Ver, Mimram, Beane, Ivel and Darent, with some examples shown below.

Note. 1. baseflows derived from gauged flows using baseflow separation software. 2. Plotted baseflows usually lead GWLs by 2-3 weeks

And, of the course the River Tarrant.

The implication is that groundwater level is the dominant control on flow, with abstraction largely affecting flows indirectly by lowering groundwater levels relative to their natural state.

This is not a theoretical construct imposed on the system, but a pattern observed in the data and then represented mathematically.

The CSF equation and non-linearity

The CSF model expresses this relationship in the form:

Q = a(GWL – b)^c

where the constants are calibrated to fit observed data, where the constants are calibrated to fit observed data. Q is flow and (GWL – b), is the height (h) of the groundwater at the observation point over the stream bed at the discharge point.

As shown on the above plots for the Rivers Chess, Misbourne, Mimram and Ver. The relationships between GWLs and baseflows is very strong for “pure” chalk streams with baseflow indices over 90%, like the Chess and Misbourne in the above plots. In rivers like the Darent, with mixed geology including some tertiary deposits, the baseflow indices are below 80% and the relationships show more scatter, but are still plain to see.

A key feature of the relationship is that it is non-linear: increases in groundwater level produce disproportionately larger increases in flow. The model captures this behaviour through the exponent (c), which typically lies between 2 and 2.5 as seen on the plus above.

This non-linearity can be understood heuristically. As groundwater levels rise:

  • the area of saturated ground contributing to spring flow increases, and
  • the hydraulic response of the system becomes more pronounced

Together these effects produce a more-than-linear increase in discharge. While the precise physical mechanisms are debated — ranging from valley geometry to fracture density—the existence of non-linear behaviour is widely observed in the data.

The CSF model does not claim to resolve all underlying processes, but it does provide a consistent way of representing this empirical relationship.

Calibration and transparency

Jane raises concerns about how model parameters — such as subsurface flow and specific yield— are derived.

In the CSF model, these parameters are obtained through calibration: the constants are adjusted until the model reproduces the observed relationship between groundwater levels and streamflows over historic records.

This is a standard empirical approach. The parameters effectively encapsulate the combined influence of aquifer properties such as permeability, transmissivity and storage (a) and valley shape combined with other components of the non-linearity, such as fracture density rising with altitude (b).

The method is described in the RTPS report (page 22), including the treatment of throughflow and specific yield. While simple, it is transparent: the model is designed to reproduce observed system behaviour rather than simulate all underlying processes explicitly.

The key question is therefore not how the parameters are derived in isolation, but whether the calibrated model reproduces reality with sufficient fidelity. On that measure, the fits to historic data are strong.

Is simplicity a weakness?

Prior to the Affinity Water conference in 2022, the CSF model was reviewed by several hydrogeologists. While they noted its simplicity and raised questions about parameter estimation, they did not dismiss the approach. On the contrary, they regarded the results as promising and worthy of further consideration.

Andy Binley wrote: “I must say that the modelling results and analysis of historic data appear convincing to me. You have modelled a substantial set of historic records using a simple lumped approach – the fits to data are impressive and appear to outperform the EA model.”

Jonathan Paul wrote “The reports showcase an interesting, if highly simplified, analytical relationship between groundwater level and river discharge. Initial results look very promising, but greater clarity in how your exponents a and b were obtained would be welcome.”

Jane herself noted in earlier correspondence that the model was “a neat little model” and more satisfactory than some alternatives, albeit highly simplified.

This highlights a tension in the review. The same simplicity that was previously seen as acceptable — within a defined scope — is later treated as a fundamental weakness.

Yet simplified models have a recognised role. They are often used in early-stage assessment, to identify key controls and sense-check more complex analyses. If they can reproduce observed behaviour reliably, they can provide a valuable benchmark against which more elaborate models can be tested.

Conclusion

The CSF model is not a replacement for detailed 3-D modelling, nor does it claim to be. It is a simplified, empirically calibrated tool designed to capture the dominant relationship between groundwater levels and streamflow.

Its conceptual basis is explicit, if simplified. Its parameters are derived transparently through calibration. And its outputs align closely with observed data across multiple catchments.

In that context, the key issue is not whether the model is simple, but whether it is useful. If it consistently reproduces observed behaviour, then it has a legitimate role — particularly in testing the robustness of conclusions drawn from more complex models.

To dismiss it on the basis of its simplicity alone risks overlooking precisely the kind of evidence that can help identify uncertainty in groundwater impact assessments.

Tarrant update 1 – the Environment Agency’s modelling contest

Posted in UncategorizedTagged , 3 Comments

With uncanny timing (following my post Tuesday last week), on Friday the Environment Agency forwarded to the River Tarrant Protection Society the adjudicatory report of their independent expert. (I’ve posted a copy at the foot of the page but have redacted a few personal details)

I received a lot of interested feedback from last week’s post. My intention had partly been to help inform other groups facing similar struggles in other parts of the Chalk, so I was very pleased that I seemed to have done that and to have catalysed a conversation about the uneven, David versus Goliath contests we face.

I’m uneasy about the EA’s approach to this case. Why take so long to respond? Why be so apparently reluctant to engage with the proactive, positive suggestions in the River Tarrant Protection Society (RTPS) report? Why not agree to a meeting? Why set out with an adjudicatory contest between models – which is almost bound to find in favour of the status quo – instead of addressing the full package of evidence?

A quick bit of background. 

Please read my previous post for the fuller picture, but in short:

  • The River Tarrant is a chalk stream in Dorset where locals have long been concerned (50+ years) about the impact of abstraction.
  • It is a breeding stream for critically endangered Atlantic salmon.
  • The lower stream is drying far more frequently now than it did in the past. We don’t know for certain the flow patterns before the era of abstraction but there are no records of lower river drying before the 1950s (by contrast, there are records of natural upper river drying, for example in 1929) and there are five Domesday mill sites on the middle and lower river, which suggests the stream was reliably perennial.
  • As abstraction has increased from the 1970s to today the drying frequency has climbed from about once per decade (1976, 1989, 1995) to every year (2015, 2016, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025).
  • In 2018 Wessex Water was obligated to lower public water abstraction in the Bourne and Wylye catchments. To achieve this they constructed a grid to move water north from “under-utilised sources” in the Stour valley. 
  • As part of this process the Environment Agency asked Wessex Water to produce an environmental impacts report into any possible impacts on the chalk streams of the Middle Stour, specifically the River Tarrant, the Pimperne Brook and the North Winterbourne.
  • The review concluded that: 
    • only a single, small and long-running pump impacted flows in the Tarrant and by only a negligible amount.
    • a single, much larger pump had no impact on flows in the Pimperne winterbourne (nor the neighbouring Tarrant)
    • impacts on the North Winterbourne were negligible.
  • The grid went ahead, since when the Tarrant has dried every year.
  • In 2024 the River Tarrant Protection Society sent an independent report authored by John Lawson to the Environment Agency which questioned the Wessex Water assertion that the abstractions were having no impact on either the Tarrant or Pimperne. The report used the results of relatively simple “lumped parameter” modelling to show that there may indeed be an impact, and added a considerable weight of historical and recent empirical evidence to back up its claims
  • In the face of this uncertainty the RTPS has asked for more detailed investigations and has also proposed a scheme of abstraction realignment that would alleviate the drying in the Tarrant. 

The Environment Agency has taken a long time to respond and thus far the terms of reference for their investigation have been very limited. 

Independent review

Jane Dottridge, an expert hydrogeologist with Mott McDonald, was asked to compare the two modelling approaches: Wessex Water’s modelling (developed with the EA) compared with John Lawson’s modelling. To quote Christopher Greenwell, the EA Water Resources Lead, “I wanted to focus on the two modelling approaches first, since this formed one of the most fundamental challenges within the RTPS report … What Jane has done is not simply to consider John Lawson’s alternative approach but also to reassess the approach undertaken by Wessex Water during their investigation of the impacts of the Middle Stour sources.”

The RTPS was not consulted on the scope, terms of reference or the choice of reviewer.

Jane Dottridge previously reviewed the Wessex Water Middle Stour report in 2018. She has stated in her letter / report that she draws on her prior work as external reviewer to the Wessex Basin Model and her knowledge of that model. 

More than that, Jane has encountered John’s work before, in another context. In preparation for a meeting convened by Affinity Water about the River Ivel in 2022, Jane was recommended to me as someone who might take an independent, helpfully critical view of John’s work and modelling approach. She sent some very useful notes of quite a technical nature. Arguably, her in-a-nutshell verdict was summed up in her statement: “My problem with this model is that it is very 1-d and doesn’t report any water balances. But it is a neat little model and much more satisfactory than some of the others I’ve seen recently.”

This we thought fair enough. John’s modelling wasn’t intended to rival, let alone replace the more complex 3-D modelling used by water companies and the Environment Agency. Instead it is proposed as a solid sense check, especially when the claims of water companies seem questionable, a tool for grass-roots organisations that can be used to usefully question unjustified certainties around these oft repeated claims of “no impact”.

In the meeting itself Jane was more critical of John’s modelling than she had been in our correspondence, describing it as a circular argument with a fitted-up recession to make calibration look right and “pop out some numbers”. It took Rob Soley to propose that the lumped parameter model had its value as a “first pass” to identify potential issues. Another hydrogeologist who we had spoken with before the meeting – Andy Binley –  also defended John’s model for what it is, a simple, numerical model calibrated to predict flows, not all the other complexities of an aquifer system. Jane suggested the idea of a tiered approach to modelling – begin with simpler lumped parameter models, progressing to more complex physics-based models if simpler models don’t provide enough certainty. 

Finally she added – and I have related this discussion not only because the roles of different complexities of modelling were not judged as mutually exclusive by Jane, Rob or Andy, but also because of Jane’s final point: she said that “models should be backed up by data and monitoring“.

So, why limit the scope of the review?

Christopher Greenwell stated that he wanted to focus on a review of the modelling approaches since “this formed one of the most fundamental challenges in the RTPS report”. RTPS weren’t given an opportunity to influence this decision, or to argue that John’s modelling outputs were part of a rounded package of evidence that included historic testimony, news reports and empirical observations.

We can see in Jane’s letter that the scope of the review did indeed focus solely on hydrogeology and groundwater modelling and that it excluded ecological, historical and qualitative evidence. This has the effect of narrowing the debate to something more like “which model is better” instead of addressing the more appropriate question: “what does the the sum of the various strands of evidence say about possible or probable abstraction impacts?”

Clearly, hydrogeology is an inexact science, is inherently uncertain. Groundwater systems — especially chalk — are structurally very complex and models of them are really only crude approximations of the living entity, no matter how much refinement is built in. They are dependent on assumptions and do not constitute primary evidence. Good scientific practice, therefore, should integrate the modelling with the other evidence. Which is exactly what the RTPS report did.

The EA’s approach – at least thus far – is a sort of backwards hydrogeology. It excludes archaeology, geomorphology, ecology, historical records, empirical evidence, testimony and conflates modelled output with evidence in the real world.

Besides, the RTPS model was never intended to win a modelling contest. It was intended to demonstrate that an alternative conceptual model can reproduce the observed behaviour of the stream and suggest that therefore the Wessex Water conclusions may be unsafe.

WFD rules

It is also worth pointing out that WFD assessment rules specifically state that decisions should be made on the weight of evidence, not a single line of analysis. If there is credible uncertainty, plausible mechanisms of impact and observational evidence consistent with impact – all very clearly set out in the RTPS report – then a regulator cannot safely conclude “no impact”.

The legitimate role of historical and qualitative evidence

The RTPS report uses various strands of evidence to try and establish:

  • the baseline condition of the stream
  • changes in the flow regime over time
  • the timing of the changes relative to the advent and then increases in abstraction.

For example:

  • The lower river dried rarely, if at all, before 1950 when abstraction began.
  • Between 1970 and 2000 the lower river dried about once per decade.
  • In the last decade, when abstraction has increased yet further, it has dried almost every year.
  • The exception of 2017 coincided with a long-term shutdown of Black Lane pumping station

This is very solid evidential reasoning, layering historical, hydrological, circumstantial and mechanistic evidence. The RTPS report advances a very legitimate scientific hypothesis, of which the modelling is just one part.

Thus far the Environment Agency’s approach:

Places too much reliance on model supremacy. The review as framed thus far implies that a model provides a more reliable basis for conclusions than any other strand of evidence. Models are inherently uncertain.

Fails to apply “weight of evidence”. The EA review evaluates the models but does not integrate them with the unarguable flow-regime changes, the ecological evidence, the historical evidence, the observed anomalies (2017).

Narrows the focus to short-term datasets. Historical evidence, for example Domesday mills and the presence of Atlantic salmon, provide a legitimate long-term context and capture a picture of the system behaviour before any monitoring record. This is really valuable information and should not be ignored. If you exclude these you bias analysis to short-term datasets that are all influenced by abstraction. 

Misunderstands the RTPS objective. The RTPS model is criticised for its simplification of aquifer properties and structure and lack of conceptual detail. However, the RTPS model was not intended to outscore the Wessex Basin mode, rather to challenge and question its unjustified certainties.

Excludes the RTPS from dialogue. The RTPS sent their report 7-months ago and requested a meeting. Thus far the only meaningful engagement has been the receipt of this report.

By turning this into a modelling contest the EA – thus far – appears to have stacked the deck in favour of the status quo. The EA’s approach is at odds with the more inclusive way forward agreed in during the framing of the multi-lateral CaBA chalk streams restoration strategy. Recommendation 11 in the strategy advocated the importance of knowledge and model sharing and said it was important to “include stakeholders in the discussion and decision-making”.

**

In my next post I will take a look at the Wessex Basin Report, the RTPS report and Jane Dottridge’s adjudication and try to show why – even under the terms of the comparison – the RTPS case is strong and should not be dismissed.

tarrant abstraction impact review 2026 final copy REDACTEDDownload

A debate in parliament on “protecting and restoring river habitats”

Posted in UncategorizedTagged , , , Leave a comment

Pictured above: sewage? No. Road run-off from a mid-summer rain-shower. 

You may remember Sophia’s petition for the protection of chalk streams, which quite easily surpassed the 10,000 signatories needed to elicit a letter from Defra, if not enough to trigger a debate in Parliament. However, a debate on river health was had recently (29th January) and chalk streams were mentioned several times.

The text of that debate can be found by clicking this LINK

I probably ought to let you all judge for yourselves what it amounts to or signals.

Personally, I have reservations about how easy it is now to dump blame on the water companies. Not that they don’t deserve a great deal of blame, but the parlous state of our rivers is not only down to water company malpractice. Our laws are at fault. Our regulation is at fault. Our pricing of water is at fault. Cheap food is at fault. Highways maintenance is at fault. Flea treatments are at fault. How much water we all use is at fault. Wet wipes are at fault. The ever increasing size of modern tractors is at fault. Our historic inheritance of mills, canalisation and dredging is at fault. The last three, historically the most remote, are in combination with all the above present day ills, the most significant impacts of all and yet receive virtually zero attention. Having said that, Minister Hardy, did at least extol the virtues of re-wriggling rivers.

Capping water company director’s bonuses might well be one in the eye for some of the folk who should be held to account, but I’m not sure it’s going to really do much to restore our beleaguered rivers more generally or chalk streams in particular.

For that we need some forensically focussed realignment of environmental law, economic drivers and regulation aimed not just at the water industry but at all the pressures that hold our rivers back.

There’s much in Minister Hardy’s final statement to indicate a general commitment to the above.

“Restoring the health of our rivers is fundamental to safeguarding nature, supporting resilient communities and securing our water environment for generations to come. The Labour Government are committed to delivering the most comprehensive programme of reform ever undertaken. It involves strengthening regulation, boosting enforcement, investing in innovation, supporting local partnerships and empowering farmers, land managers and water companies to play their part. From national action on agricultural pollution and chalk stream protections, to ambitious local projects in South Dorset, we are driving real, long-term improvements. Together, those measures demonstrate our unwavering commitment to cleaner water, thriving habitats and a healthier natural environment across England.”

The devil is in the detail, however, and in the end it comes down to that which can be quantified. How much less water will be abstracted from our chalk aquifers? By what date? How will we prioritise abstraction reduction so that we don’t repeat the mistakes of the way we have prioritised phosphorus reduction (ie driven by economics rather than ecological benefit)? Where will the replacement water come from? Will we now, finally, incentivise phosphorus reduction from tiny sewage works in headwaters and tributaries? Exactly how will we do that? Will we persuade or incentivise farmers to adopt better ways to keep soil on their land? Exactly how? Will local authorities adopt less damaging practice in local road maintenance programmes? When by? Etc. Etc.

Specific actions. Specific numbers. Specific dates. These are the things we tried so very hard to get into a Chalk Stream Recovery Pack. Without them it’s all so much fish and chips wrapper.

Dumb, damaging and pointless drainage: one of the many things that impact chalk stream health.

A letter to Minister Hardy

Posted in UncategorizedTagged , Leave a comment

Ali Morse – chair of the CaBA chalk stream group – has written a letter (see PDF below) to Minister Emma Hardy (pictured above with the Yorkshire Wildlife Trust beside the Foston Beck) encouraging her to support measures to restore and protect chalk streams, but also expressing disappointment that the water White Paper and NPPF have not given us the promised assurances that chalk streams will get the “recognition and protection they deserve.”

Some time before the last election – and sensing, without any great gifts of foresight, a change of government – I spoke with Daniel Zeichner, the Cambridge Labour MP, about how important it would be to continue our chalk stream restoration work beyond the election, to harness the momentum gained from a strategy that had been signed up to by all sides. I might have been naive (though not as naive as those firebrands who correlated conservation nirvana with a change at Westminster) but Zeichner agreed wholeheartedly. He said that Feargal Sharkey – who was vigorously campaigning for Labour at the time – would hold them all to account if they didn’t do something.

And yet in spite of all that, the responses of the new(ish) government to repeated pleas for the greater protection of chalk streams have been underwhelming, to say the least. Having filibustered the progress of Minister Pow’s promised Chalk Stream Recovery Pack, Defra used the election as a means to nudge the pesky document under the carpet and finally to bury it altogether.

But when I met Minister Hardy last summer on the banks of Yorkshire’s Foston Beck, I met someone who I felt was motivated – as Minister Pow had been – to help chalk streams. She seemed genuinely keen to listen and help. Genuinely flabbergasted by some of the anomalies in existing environmental law that, for example, drive ever more expensive sewage treatments to works where the benefit to wildlife is minimal, while ignoring those places that need it most. But I also sensed a hesitancy to commit. Having worked for a year with Defra trying to midwife the Recovery Pack I knew why. Trying to persuade that unelected part of government to do anything differently is like pushing water uphill, whether you’re a Minister, an eNGO or individual citizen.

As Ali points out in her excellent letter, during the passage of the Planning and Infrastructure Bill we saw consistent and strong cross-party support for measures to protect chalk streams. We heard ministerial assurances from the despatch box that effective chalk stream measures would be included in upcoming policies.

But we haven’t seen much of substance, thus far.

No surprise, perhaps. There is no Damascene moment in conservation. I’ve been banging on about chalk stream protection since the dark days of the late 1980s when abstraction was at its peak, when cattle poached the riverbanks to bits, when land drainage engineers ruled the waterways, when zero phosphorus was removed from sewage and when “restoration” of rivers was an eccentric form of guerrilla resistance. Things are better than that now, though sometimes it may not feels as if they are.

To that end, Ali has extended to Defra the hand of continuing cooperation backed by the wealth of expertise now assembled under the umbrella of the CaBA chalk stream group, very ably managed by Alison Matthews. And I have invited Minister Hardy to come and visit the River Chess to meet with the River Chess Association and the Chilterns Chalk Stream Project and see first hand how collaboration and persistence can bring about the recovery of a chalk stream.

Fingers crossed. As ever.

260204 Letter to Minister Hardy – Chalk StreamsDownload

Full text from the House of Lords debate ref the protection of chalk streams and the Bishop of Norwich’s amendment to the Planning and Infrastructure Bill.

Posted in UncategorizedTagged , , 1 Comment

Extracted from Hansard Report – Planning and Infrastructure Bill – Hansard – UK Parliament

Amendment 93

Moved by

Baroness Grender 

93: Clause 52, page 73, line 22, at end insert—

“(6A) Where a strategy area includes a chalk stream, the spatial development strategy must include policies on permissible activities within the area of the stream for the purposes of preventing harm or damage to the stream or its surrounding area.”Member’s explanatory statement

This amendment would ensure spatial development strategies include policies to protect chalk streams.

Baroness Grender 

My Lords, Amendment 93, in my name and that of the noble Baroness, Lady Jones of Moulsecoomb, aims to secure the future of England’s chalk streams by enshrining specific protections and standards into our planning regime. As we made clear in Committee, these globally rare ecosystems—there are only 200 in the world—are often referred to as our country’s rainforests in terms of biodiversity and they face genuine risk from piecemeal development and inadequate water management. These are risks that will only intensify without a robust and specific legislative lever.

Relatively recently, I went for a customary walk in a beautiful green space in south-west London, only to discover that the beautiful River Wandle, home to brown trout and kingfishers, had been destroyed by a devastating diesel leak. The Government intend to streamline housebuilding and environmental measures in tandem, but the practical reality is stark.

Chalk streams are uniquely vulnerable. Abstraction of water, chronic pollution and unchecked development have led to tangible declines in many local areas. In 2023, the Liberal Democrats collected data through freedom of information requests, which revealed that one in 10 chalk stream sewage monitors were faulty, with some water companies having much higher rates of broken or uninstalled equipment.

Amendment 93 delivers a targeted solution: a statutory driver for sustainable drainage standards before any development interfaces with public sewers, closing a loophole that currently exists and has allowed cumulative harm to chalk streams. This amendment would ensure that developers are compelled to apply national standards for drainage and water treatment ahead of any permissions, rather than leaving mitigation as an afterthought.

Amendment 94 in the name of the right reverend Prelate the Bishop of Norwich complements this approach, and I thank him for the work he has done on this issue and his environmental expertise, which he has brought to this debate. Amendment 94 tightens oversight and demands full transparency in environmental impact reviews on watercourses at risk, an essential safeguard for communities whose local rivers are too often treated as collateral damage by the planning system’s inertia.

None of us should accept that cleaner, safer waterways are an optional extra and a nice to have. By adopting an amendment on chalk streams and supporting, out of these two amendments, Amendment 94, this House will signal that nature restoration, water quality and sustainable infrastructure are not in competition but can be advanced through co-ordinated and legally binding steps. I urge noble Lords to support these amendments for the sake of our streams and the communities they sustain.

If the right reverend Prelate the Bishop of Norwich moves to a vote, these Benches will support him. It is right that, with something as crucial as our unique chalk streams, we ask our colleagues in the House of Commons to think again and strengthen and protect in law this ecosystem that is almost unique to England. I hope that this House will unite in voting for Amendment 94 and protecting this rare heritage for future generations.

Amendment 94

The Lord Bishop of Norwich 

My Lords, I shall speak to Amendment 94, and I thank the noble Earl, Lord Caithness, the noble Viscount, Lord Trenchard, and the noble Baroness, Lady Willis of Summertown, for their support. I am most grateful to follow the noble Baroness, Lady Grender, who has just spoken so powerfully about her amendment, as well as offering her support for this amendment. Amendment 94 would require a spatial development strategy to list chalk streams in the strategy area, outline measures to protect them from environmental harm and impose responsibility on strategic planning authorities to protect and enhance chalk stream environments.

Chalk streams, as we have heard, are a very special type of river. Some 85% of the world’s chalk streams are in England. They are fed primarily by spring water from the chalk aquifer, not rain, which means that they have clear, cold water and very stable flows. These globally rare habitats are found in a broad sweep from Yorkshire and the Lincolnshire Wolds through Norfolk, the Chilterns, Hampshire and Dorset. The Bure, Glaven, Wensum, Test, Itchen and Meon are river names that come to mind flowing, as they do, through the tapestry of English history and in our literature, such as the River Pang-based Wind in the Willows. They are rich in minerals, especially calcium, and this “base rich” environment supports a distinctive and rich ecology.

It is no wonder that this amendment and a similar one in the other place have received such positive support, including in your Lordships’ Committee. What it seeks to do is such an obvious thing, for what we love, we should desire to protect; what we value, we should safeguard; what is of global significance, we should be deeply proud of.

I am grateful that the Minister responded to my letter to her about my amendment. However, her response was far from reassuring in two ways. First, the Government have pointed to local nature recovery strategies as a way of protecting chalk streams. These could, of course, in future be capable of considering, avoiding and otherwise mitigating for direct damage to these habitats, such as occurs from the footprint of a development near a chalk stream. However, to do so, LNRSs will need more bite in the planning system than they currently have. We are still waiting for the regulations designed to do precisely that, placing a duty on local planning authorities to take account of the nature strategy when making planning decisions. 

We are still waiting for that to be commenced, and it is now a full two years after these regulations were promised in the Levelling-up and Regeneration Act 2023.

Even once the regulations are passed, LNRSs will not be well placed to map, quantify and avoid or mitigate for the offsite impacts of development such as downstream pollution or the additional water that will be abstracted from chalk streams or their aquifers to serve new homes. These very real threats to our chalk streams, over areas much larger than are covered by strategies, cannot be addressed by LNRSs.

Secondly, the Government have pointed to their plans to limit overabstraction by water companies through amending licences, but their target achievement date is 2030. This could take far, far too long and be far, far too late for many threatened chalk streams. The current abstraction situation is grave. Water companies are not sourcing their water from chalk streams within sustainable limits. The Catchment Based Approach’s chalk streams annual review 2024-2—a mouthful of a title—published last week, reports that a third of chalk streams do not have healthy flow regimes. This CaBA report also highlights additional water bodies where, despite flows being classed as compliant overall, abstraction can cause significant local impacts in parts of the watercourse. For example, in the River Loddon, upstream areas are impacted by abstraction but, because of wastewater discharge downstream of them, flows at the assessment point are classed as compliant. If overabstraction occurs for a sustained period upstream, the whole chalk stream could well dry out.

In light of the growing and urgent challenges facing our chalk streams, we cannot afford to wait for LNRSs to have more planning bite, or for 2030, when the abstraction licence amendments come into effect. We need Amendment 94 so that spatial development strategies are equipped to enable planning authorities to direct development away from areas where development footprints, pollution and overabstraction could sound the death knell for declining chalk streams. I will certainly listen to the Minister’s response with care. However, if this amendment continues to secure wide support, I will look to test the opinion of the House.

Baroness Willis of Summertown 

I am pleased to add my name to the important amendment tabled by the right reverend Prelate the Bishop of Norwich, and to Amendment 92 in this group, because, let us be honest, we are not starting from a good place with chalk streams. As mentioned by my noble friend, the current status of these unique and extremely rare habitats in the UK is poor, with more than three-quarters failing to meet good ecological health standards. This is precisely why the chalk streams became such an important issue for debate in the Levelling-up and Regeneration Bill. I remember only too well the same Front Bench colleagues debating long and hard for their protection.

The chalk stream recovery plan, announced by the previous Government, was seen by many, including me, as a good step in the right direction. But here we are again, with chalk streams back in the firing line and, despite the reassurance from the Minister on Report that local nature recovery strategies could propose priorities for their protection, the problem with our planning system is that it requires local authorities only to have regard to our LNRSs, which is not strong enough to protect these vulnerable habitats. We came across this a number of times in the Levelling-up and Regeneration Bill. Those words are etched in my memory.

Also, although the NPPF recognises the importance of irreplaceable habitats, chalk streams, much to my alarm—and, I am sure, to that of many in this House—are not specifically listed as protected habitats. Therefore, they do not have the overarching level of protection in the Bill, through the spatial development strategies, in the same way other protected habitats do. The only hope left, therefore, is the chalk stream nature recovery plan, launched by the previous Government. However, in reply to the question on this asked in Committee by the noble Viscount, Lord Trenchard, who sadly cannot be here today, the Minister stated that even this is now on hold because it is out of step with the ambitious programme of water reforms proposed by the Government. Perhaps the Minister can say for how long it will be on hold, as a result permitting further damage to occur in these unique freshwater habitats.

I say this because time is of the essence here. As an ecologist, I went back to look at the literature. Research on chalk streams has demonstrated that while removing pollution can result in the improvement of water quality within a month to a few years, ecological recovery can take between 10 and 20 years. The more damage we do, the longer it will take for them to recover.

Lastly, surely there must be some no-go habitats in some of our river catchments, and these chalk streams should be one of them. I therefore urge the Minister to agree to this amendment, within which the spatial development strategy would mandate the sort of responsibilities that lead to the protection and enhancement of these unique and rare chalk stream habitats.

Lord Bellingham 

My Lords, I support both amendments. I made a speech in Committee in which I laid out very similar arguments to those put by the right reverend Prelate and the noble Baroness, Lady Willis. I will not repeat them now, except to say that the right reverend Prelate referred to a number of chalk streams in my old constituency of North West Norfolk. These incredible assets—these unique and precious assets—are at risk as we speak. I say to the Minister that neither amendment is particularly demanding. They are quite modest in their overall fabric and intent. If the Government are serious about their environmental credentials, and about trying to do something for the countryside, I urge them, please, to accept these amendments.

The Earl of Caithness 

My Lords, I have put my name to the right reverend Prelate’s amendment. I am delighted to see him back in the Chamber; we missed him in Committee.

My noble friend Lord Roborough was absolutely right when he said in Committee that all rivers are important. Yes, that is true, but chalk streams are that bit more important. The reason for that is that we have 85% of the world’s chalk streams. We are custodians for that majority, but 83% of those chalk streams do not meet good ecological standards. We have handled the whole situation very badly. I think we have taken a retrograde step with this Government, who have dispensed with the chalk stream recovery pack, which the noble Baroness just referred to.

I have written to the Minister and told her that I will ask her a number of questions. I have given her forewarning, so I expect replies. In what respect did that chalk stream recovery pack fall short? It was nearly ready to go when the Labour Government took over after winning the election. They could have pressed the button; that chalk stream pack focused on some difficult questions that nobody had fully addressed before, so why have they torpedoed it? What do they propose to do that will be better than that pack had proposed?

Let us go down to some specifics of the pack. It had time-bound commitments to reduce groundwater abstraction on numerous chalk streams which, according to the Environment Agency’s own data, are unsustainably extracted: for example, the Darent in Kent, where over half the rainfall that feeds the river is taken away for public water supply. There was a timescale for getting that right. Will the Government stick with that timescale or will there be something longer? Do the Government have plans to move water abstraction further downstream, rather than at the headwaters of these rivers?

The chalk stream pack also had a timebound commitment to address the hundreds of small sewage works in chalk streams that do not remove phosphorus in the treatment process and where there is currently no policy or incentive to drive investment. What are the Government going to do better to give a good timescale to get all those water treatment plants in good order? The pack also addressed run-off from highways and local roads, which I have spoken about before in your Lordships’ House, and how damaging it can be to chalk streams in particular because of the added silt. The CaBA chalk stream strategy recommends revised best practice guidelines for local councils that give more protection to chalk streams. Do the Government have better plans than that? The pack also put forward solutions to reform the farming rules for water, which are currently ineffective. What are the Government going to do to replace that recommendation?

I did not mention this question when I wrote to the Minister, but I will add it now: how do the Government intend to address the physical dysfunctionality of many chalk streams moved, straightened, dredged or dammed over the centuries and put them back to their natural state? In destroying the hard work of some very good, able and committed people who produced the chalk stream pack, the Government have alienated some potential friends in their effort to improve the environment. How are they going to get friends back onside when, after all that work, they have just dismissed it as though it did not matter? What plans do they have to include such people in the future to try to improve the whole river system for chalk streams? It is no good taking just one little area in one district or county council, because chalk streams do not understand those borders; they flow through lot of different councils. The whole thing has to be tackled on a holistic basis, and the only way to do that is by supporting the right reverend Prelate’s amendment.

Lord Roborough 

My Lords, I shall speak to the amendments in the names of the noble Baroness, Lady Grender, and the right reverend Prelate the Bishop of Norwich. I am grateful for their excellent, informative introductions. We on these Benches tabled similar amendments in Committee. The amendments share a vital purpose: to ensure that our planning system gives proper recognition and protection to chalk streams, one of our most distinct and rarest natural habitats. These streams help define our landscapes, support unique biodiversity and supply water to many communities. The amendments would require spatial development strategies to identify and protect chalk streams, setting out the responsibilities for planning authorities in their stewardship.

These are sensible, constructive proposals and I am grateful to those who have tabled and supported them. We will support the right reverend Prelate the Bishop of Norwich if he divides on his amendment this evening. Will the Minister say whether she considers chalk streams to be irreplaceable habitats, like ancient woodlands, and therefore deserving of similar policy protection? The case for stronger recognition of chalk streams within our planning system is compelling. They are an irreplaceable part of our natural heritage and a globally important asset, and the way we plan for growth must reflect that.

I hope the Minister has heard the House and will be able to accept these amendments, and explain, as the noble Baroness, Lady Willis, and my noble friend Lord Caithness have asked, why our chalk stream restoration strategy is on hold.

Baroness Taylor of Stevenage 

My Lords, I thank the noble Baroness, Lady Grender, and the right reverend Prelate the Bishop of Norwich for Amendments 93 and 94, which propose additional statutory obligations for strategic planning authorities in relation to the identification and safeguarding of chalk streams. With 85% of the world’s chalk streams found in England, these unique water bodies are not just vital ecosystems but are indeed a symbol of our national heritage. The Government are committed to restoring them, which is why we are taking a strategic approach to restoring chalk streams. Working in partnership with water companies, investors and communities, the Government will introduce a new water reform Bill to modernise the entire system so that it is fit for purpose for decades to come. This is essential to restoring chalk streams to better ecological health and addressing the multiple pressures facing these habitats.

Alongside the programme of ambitious reforms, the Government are continuing to deliver vital improvements and investment for chalk streams, including £1.8 million through the water restoration fund and water environment improvement fund for locally led 

chalk stream projects. Over the next five years, water companies will spend over £2 billion on chalk stream restoration.

The Government remain firmly committed to the restoration and protection of chalk streams. Plan-makers and decision-makers should recognise these habitats as valued landscapes and areas of high biodiversity. They deliver essential ecosystem services, contribute significantly to natural capital, and should be identified and protected through local plans.

As I emphasised in Committee, local nature recovery strategies provide a tool for identifying and enhancing chalk stream habitats. These strategies map priority areas for nature and are informed by key environmental data, such as the assessments carried out under river basin management plans. Under Section 12D(11) of the Planning and Compulsory Purchase Act 2004, spatial development strategies must already take account of relevant local nature recovery strategies.

In answer to the points made by the right reverend Prelate, local nature recovery strategies are a legal requirement and are prepared by responsible authorities, typically county or combined authorities appointed by the Defra Secretary of State. There are 48 LNRS areas and lead authorities covering the whole of England; there are no gaps, and no overlaps. LNRS responsible authorities work closely with local partnerships, involving all local planning authorities, to identify and map proposed areas for habitat management, enhancement, restoration and creation for biodiversity and the wider natural environment. The West of England Combined Authority published the first LNRS in November 2024. Five more have since followed: North Northamptonshire Council, Cornwall, Isle of Wight, Essex and Leicestershire. The remaining 42 are expected to be published by the end of 2025, or shortly thereafter.

I will also address the right reverend Prelate’s point about the provisions in the LURA. The Act created a duty requiring plan-makers to take account of LNRS. This builds on the existing requirement on all public authorities to have regard to LNRS in complying with their duty to conserve and enhance biodiversity. This duty will be commenced as part of wider planning reforms later this year.

Where a strategic authority considers chalk stream protection to be of strategic importance, Section 12D(1) requires that spatial development strategies include policies on land use and development that address such strategic priorities. Authorities will therefore be able to include such policies where appropriate.

Furthermore, planning policy is clear that decisions should prevent new and existing development contributing to unacceptable levels of water pollution. Where water quality has the potential to be a significant planning concern, an applicant should explain how the proposed development would affect a relevant water body in a river basin management plan and how they propose to mitigate the impacts.

Fixing systemic issues is essential to addressing the multiple pressures facing these habitats, and restoring our chalk streams to better ecological health is part of our overall programme of ambitious reforms for the water sector.

I will respond to the points made by the noble Earl, Lord Caithness. I am more than willing to answer all his points—I will try to do so briefly. It might have been more helpful to have them in writing before today, but I will cover the points he has raised. First, on the time-bound commitments to reduce ground water abstraction, we are tackling one of the biggest threats to chalk streams by reducing harmful abstractions by an estimated 126 million litres daily by 2030, protecting vital water flows to these fragile ecosystems.

Companies covering chalk stream areas, such as Affinity Water and South Staffs Water, have made specific commitments to reduce abstraction from chalk streams. Affinity Water has committed to reducing abstraction by 34% by 2050. Portsmouth Water is building a new reservoir in Hampshire to protect the River Test and the River Itchen—this is the first new reservoir to be built since the 1970s. In June 2025, the Environment Agency updated its national framework for water resources, which set out the importance of chalk streams and how we will include their needs in water resources planning and decision-making.

On time-bound commitments to address hundreds of small sewage works in chalk streams that do not remove phosphorus, under the Environment Act, to achieve the 80% reduction in phosphorus load discharge, the phosphorus improvement driver prioritises action for catchments that meet one or more of the following criteria: catchments with water framework directive regulations—phosphorus standard failures; catchments with identified nutrification issues under the Urban Waste Water Treatment Regulations; and catchments where phosphorus targets set by conservation policy advisers are exceeded. That prioritisation ensures targeting to achieve the best environmental outcomes.

In addressing run-off from highways and local roads, the Defra Secretary of State has committed to including a regional element in the new water regulator. We are considering how road or highway run-off and urban diffuse pollution can be managed at a regional or local level as part of moving to a catchment-based approach.

Lastly, on the reform of farming rules for water—which the noble Lord said in his letter are currently ineffective—the levels of water pollution from agriculture are unacceptable. We are looking at reforming the regulations, including the farming rules for water, as a priority within a suite of broader interventions. We are also working with farmers, environmental groups and other parties to improve the farm pollution regulations to make sure that they are simple and effective. This will allow us to deliver pollution reductions and clean up our waters while supporting farm businesses to grow. I hope that is helpful to the noble Lord.

We need to continue to tackle the biggest impacts on chalk streams, including reducing the risk of harmful abstraction, and we are doing so, as I said, by 126 million litres through the amendment of water company abstraction licences, and rebuilding the water network with a record £104 billion investment to upgrade crumbling pipes and cut sewage spills. In light of all this, I hope noble Lords will not press their amendments.

Baroness Grender 

My Lords, I thank the Minister. It is very clear there is a strong feeling within this House that there is a need for something to shift and be enshrined in law. I beg leave to withdraw my amendment in order to hand over and support the right reverend Prelate the Bishop of Norwich if he decides to press his.

Amendment 93 withdrawn.

Amendment 94

Moved by

The Lord Bishop of Norwich 

Sharethis specific contribution

94: Clause 52, page 73, line 22, at end insert—

“(6A) A spatial development strategy must—(a) list any chalk streams identified in the strategy area;(b) identify the measures to be taken to protect any identified chalk streams from pollution, abstraction, encroachment and other forms of environmental damage; and(c) impose responsibilities on strategic planning authorities in relation to the protection and enhancement of chalk stream habitats.”Member’s explanatory statement

This amendment would require a spatial development strategy to list chalk streams in the strategy area, outline measures to protect them from environmental harm, and impose responsibility on strategic planning authorities to protect and enhance chalk stream environments.

The Lord Bishop of Norwich 

My Lords, I thank all who have contributed to this important debate and the Minister for her response. However, I am not convinced by her arguments; we cannot wait for a water reform Bill and have these arguments again at that stage. Amendment 94 seeks to protect chalk streams, this precious habitat which we are the custodians of. It aims to restore biodiversity and create a planning system that works with nature, not against it. At present, I am afraid, the Bill before us fails to do this for chalk streams. Thus, I seek to test the opinion of the House.

Sophia’s petition

Posted in UncategorizedTagged , , Leave a comment

Last Friday afternoon 30th May Sophia’s petition “please don’t abandon the chalk stream recovery pack” passed 10,000 names. By Monday almost another 1000 names had been added.

This is fantastic news. It means that the government must now respond.

And maybe they have, to a degree. On Monday I met Minister Emma Hardy by a Yorkshire chalk stream. Many thanks to our guide Matt Arnold from the East Yorkshire Rivers Trust.

Though we were standing beside the Boston beck, perhaps one of the least pressured chalk streams in England, Minister Hardy was genuinely keen to know more about the multiple threats to chalk streams and what we should be doing to make things better.

We discussed the extreme levels of abstraction that exist on some chalk streams, especially those near London, and the suffocating nutrient pollution that comes from innumerable small sewage works where there is no phosphorous limit or where, if one exists, it is absurdly lax. We especially focussed on the lack of clarity in catchment level decision-making, something I feel the government could help with by unambiguously signalling the importance of chalk streams.

That signal should have taken the form of the Defra chalk stream recovery pack, of course, but I’m not holding my breath for a change of heart regarding its publication. Though you never know.

I will certainly continue to push, arguing why many of the measures in the pack were low-cost no-brainers: stuff that builds on existing policy with greater clarity and purpose, that would remove blockers in bureaucracy or give clear signals to water resource groups and water companies on where to prioritise abstraction reduction or target better water quality in vulnerable headwaters or that gives support to stakeholders.

My guess is that the treasury has put more or less everything on hold while it tries to prioritise growth through development.

This is worrying. Water efficiency through demand and leak reduction, for example – THE big plays in our national framework for water resources over the next two decades – means nothing for nature, unless accompanied by actual abstraction reduction. Of itself water efficiency simply makes headroom for development. And in the current climate this is almost certainly what it will be used to deliver.

Similarly, if the water industry is left to meet the previous government’s laudable nutrient reduction targets (as set out in the Environmental Improvement Plan) via “highest technical standards” at large works downstream of large population centres where highish standards exist already, then of course this will be the preferred “cost-effective” pathway for all parties.

All parties except fish and insects who might prefer those chemicals are removed upstream of where they live. The point is, you can create a great headline figure for phosphorus removal where it makes little ecological benefit, but why not direct the targets towards their purpose?

Without direction from government or its regulators on how to prioritise either abstraction or phosphorus reduction, economic efficiency of a decidedly anthropogenic kind will decide. River life will receive little benefit from initiatives intended to restore it.

Frustratingly, it’s all about economics – no matter who’s in charge – and so long as water is as cheap as it is, and so long as imaginative and economically-efficient ideas like Chalk Streams First or nutrient treatment wetlands or risk-based buffer strips (all measures a recovery pack might have given prominence to) are starved of oxygen, then nature will pick up the bill.

And thus the can is kicked down the road.

It doesn’t have to be this way. The chalk recovery pack would have been Defra’s first bespoke policy document for chalk streams. This government could yet dig it out, add some oomph to the stuff that got watered down, and defy my cynicism. No one would be happier to be proved wrong.

In the meanwhile, it was a pleasure to meet the Minister and I’m very much hoping we can meet again soon on one of the Flagship project sites, the Chess, for example where Kate Heppell is leading amazing citizen science research, or the Anton, where Simon Cain and Bob Wellard are concocting imaginative re-wilding schemes. And then perhaps the beleaguered Ivel which barely flows, or the Ver whose headwaters this winter have been constantly polluted with raw sewage.

The counter-intuitive (and heretical) idea that could unlock abstraction reduction.

Posted in UncategorizedTagged , , , , , 1 Comment

It took me a while to get my head around the concepts in this post, so bear with me. This is aimed especially at eNGOs and other campaigners for chalk streams, because the more people there are who understand this counter-intuitve idea, the better. 

Here it is: you can save many chalk streams from unsustainable abstraction by conceivably using the aquifer in times of low flows and drought.

That is a head-muddler. But this idea could unlock real abstraction reduction, making the bad much better in the foreseeable future. This is far, far preferable in my view than holding out for a perfection (natural aquifers) that will never come.

It starts with my best attempt at explaining what I understand of the complexities of the interactions between groundwater, river flow and groundwater abstraction. Given that I vainly spent a long night in a hut in Iceland trying to explain the very same ideas to two angling friends of mine (they were belligerently uncomprehending in a (successful) effort to annoy me), this will be no easy task.

It is complex … kind of. It’s also quite simple really. Rather as the moon affects the tides, a simple idea leads to a complex set of manifestations.

Idea 1. Chalk streams flow from underground.

If you’re reading this blog you’ll already know that chalk streams derive most of their flow from groundwater. Rain sinks into the ground filling fractures in the underlying chalk and then lower down the slope it seeps out again as springs to create a chalk stream.

Idea 2. The level of the groundwater drives the flow in the river.

This is pretty simple. I used the bucket analogy before. Drill a single hole in the base of a bucket. Fill the bucket with water. As the bucket fills gravity drives water at an increasing velocity out of the hole. Now stop filling and let it empty. The flow diminishes to a trickle. EVERYONE gets this because it’s the same when you pee!

The rate of flow from springs in a chalk valley is driven by the hydraulic head of the groundwater above the springs. The higher the level, the greater the flow …
… In more or less the same way as the water level in the bucket determines the force at which the water is driven through holes in the side of the bucket.

Idea 3. Groundwater rises in winter and falls in summer.

If you pour water into the bucket faster than water can leave it through the hole(s), the level in the bucket rises. If you stop pouring water in, the level falls as the bucket drains. This is exactly the same with a chalk aquifer. In winter, when it rains a lot, and it’s cold and the ground is wet and nothing is growing, more rain flows into the aquifer than can leave it and so the groundwater level rises. In summer, much less rain – if any – reaches the aquifer and so the groundwater level falls.

Groundwater rising. This chalk valley is dry most of the time but in February 2021 when recharge vastly exceeded discharge, it had filled to overflowing.

Idea 4. The higher the groundwater rises up the valley, the more the water pours out of it.

As groundwater level rises, stream flow increases. But not in a linear way as it would with a single hole at the base of a columnar bucket. In fact for every unit of rise in groundwater level, flow will increase by approximately X2 to 2.5 . Kind of like having twice as many holes at each level in the bucket as the level below.

There are a number of reasons for this which were debated at a recent groundwater conference. There is a summary of these ideas in Section 2 of John Lawson’s report Flow Recovery Following Abstraction Reduction which we updated following the conference and contributions from the likes of Rob Soley and Alessandro Marsili.

In short, this non-linear response is probably caused by a combination of: 

• the shape of the valley – if you imagine the groundwater filling the valley bottom and hillsides, assuming a perfect V- shape valley, for every unit increase the groundwater rises the area of saturated zone exposing springs rises two-and-a-half fold. Chalk valleys are not quite V-shaped but that’s the general idea.

• the fracture density in the chalk – which increases in the valley bottoms and with altitude. At depth chalk is very solid, but in the valley bottoms and higher up the slope and where water has flowed for thousands of years, the fracture density is much greater and the flow pathways are bigger.

• layering within the chalk – chalk accreted in layers under varying climatic / geological conditions and these layers are in turn interrupted by bands of clay and flint. These layers and the varying permeability and transmissivity can influence the way groundwater reaches with the surface.

• as the surface flow pathways lengthen (winterbournes rising higher and higher up the valley) the groundwater pathways shorten.

The fracture density and layering in the chalk, the shape of the valley and the length of flow pathways, all conspire to mean that when chalk valleys fill, flows will rise exponentially.

Idea 5. The impact of a constant groundwater abstraction has a varying impact on varying flows through the year

This is where things gets a bit more discombobulating. All of the above essentially means that as groundwater rises, flows increase exponentially. If that is true, then the reverse is true. For every unit of decrease in groundwater level, flows decrease exponentially.

This means …. drum roll … groundwater abstraction (which lowers groundwater levels) has a greater impact on high flows than low flows! This is a totally skull-tightening idea. Everyone thinks the reverse must be true. But it isn’t.

Groundwater levels and groundwater abstraction

Let’s start with the impact of groundwater abstraction on groundwater levels. In a natural aquifer system, the discharge from the valley must equal the recharge over time. Natural recharge = natural discharge / Time. This stands to reason: if it didn’t the valley would either fill to overflowing or empty (because over time one would exceed the other). 

Natural recharge derives from rain and natural discharge from river flow (and some evapotranspiration and flow through the ground). If I add another form of discharge in the form of abstraction, then the former natural discharge MUST go down. If it didn’t, the aquifer would progressively empty until there was no water left (an aside … hydrogeological literature generally describes anything less than draining the aquifer “sustainable”, because the aquifer is being lowered to a new dynamic balance, not mined. This is not the same as ecologically sustainable, however).

Look at it as simple numbers.

Natural recharge (10) = natural discharge (10) / Time.

Natural recharge (10) = abstraction (5) + natural discharge ? / Time.

What’s the new natural discharge? 5, obviously.

Now, as I showed with the bucket, the ONLY way in which the former natural discharge can go down is through a reduction in groundwater levels. If groundwater levels didn’t go down, then because the discharge is driven by the groundwater level the natural discharge would remain the same. As shown above, that is impossible.

Theis, the Isaac Newton of groundwater theory, wrote all this in 1940. The only way that the former natural discharge can go down (and balance the equation) he wrote, is by a reduction in the “thickness of the aquifer”. 

Okay, so pause and get your head round all that. 

• a single unit of rise or fall in groundwater level has a (very roughly) two-and-a-half fold impact on flows. 

• groundwater abstraction lowers groundwater levels.

• ipso facto a single unit of reduction in groundwater level at high groundwater levels has a much greater impact on flows than a single unit of reduction in groundwater level at low groundwater levels.

It still hurts the head, but the discombobulating stuff above means that at high groundwater levels groundwater abstraction reduces flows by quite a lot more than 100% of the amount abstracted. And conversely, at low groundwater levels groundwater abstraction reduces flows by quite a lot less than 100% of the amount abstracted. Albeit over time groundwater abstraction must reduce flows by (essentially) 100% of the amount abstracted (it’s generally less than that for reasons that aren’t that important to the general concept, but basically because not all discharge occurs in the form of flow).

See the chart below to see what the Chalk Streams First modelling indicates % flow recovery would be if abstraction was reduced to zero in the River Ver. It varies through the flow cycle.

The above chart from Page 52 of John Lawson’s report shows that the % flow recovery (green line) at high flows (l/h end of X axis) is well over 100% and at very low flows (r/h end of X axis) is about 30% – 20%.

Idea 6. Groundwater abstraction at low flows is like a credit card.

The obvious question is … if groundwater abstraction at low flows reduces those flows by a lot less than 100% of the amount being abstracted, where the bloody hell is the rest of the water coming from? The answer: if it’s not a direct reduction from flows at the time, it is coming from aquifer storage.

This is easy to understand if you think of a large abstraction next to a small and diminishing stream. In the winter when the stream is gushing, there is more than enough water to satisfy the pumping. In the summer the stream reduces to a trickle or perhaps even dries up. But the pumping continues. At this point the abstraction is clearly not taking water from stream flow because there isn’t any. Another aside … I’ve read hydrogeologists describe this state as abstraction having “no further effect on flows”. This might be literally correct at the time. But it is misleading. The abstraction is effecting future flows. 

When a chalk stream dries but abstraction continues it is clear that the abstraction is no longer subtracting water from the river’s flow, but from aquifer storage: this is basically a debt to future flows.

At times of low flow and into droughts, groundwater abstraction increasingly draws on storage, upon which future flows are built. If you unnaturally drain the aquifer, it will clearly take longer to fill when it starts raining again, all before the flows in the river can respond to the rise in groundwater levels.

Therefore groundwater abstraction at low flows is like a credit card: much more a debt against future flows than an impact on present flows. This is a key idea behind the confusing concept of using groundwater abstraction to unlock abstraction reduction .

Idea 7. If you turn off the pumps you get greater flow recovery at high flows than low flows.

Essentially what all this means is that when you cease or lower abstraction you get well over 100% of the amount no longer abstracted at high flows and much less than 100% at low flows. That is what the chart above shows on the River Ver.

And this is the Achilles Heel of the Chalk Streams First idea. 

Water resources needs a constant supply of water. Groundwater abstraction gives that. Chalk Streams First says “turn off (or down) the pumps and take the water from river flows much lower down the catchment”. And while you get loads of water back in winter, you get less back in summer. Generally, you must have a storage reservoir to make it work and balance out the varying recovery rates into a constant and reliable supply. 

John Lawson – who came up with the Chalk Streams First idea – has long known this. We argue (with empirical evidence) that the flow recovery at low flows is actually much higher than the most pessimistic predictions claim, but nevertheless this variation in response is an issue we have to address. The answer is a reservoir.

BUT … then you get to the prolonged droughts when water companies are under real pressure. In these times, the flow recovery could conceivably drop even lower. What to do? The public must have water. This low flow recovery at very low flows in long droughts threatens the whole idea of reducing abstraction through schemes like Chalk Streams First. Especially now that we have to plan according to 1:500 year contingencies.

Idea 7. In droughts use groundwater abstraction to guarantee public water supply … so long as you’ve turned the abstraction right down to ecologically sustainable levels 95% of the time.

The insurance against the Achilles Heel of low flow recovery in a drought is a groundwater-fed public water supply scheme. There is one in existence already called the West Berkshire Groundwater Scheme (WBGWS). It is a series of wells in the Berkshire chalk that can, in extremis, be turned on and deliver a large amount of aquifer water into the Berkshire chalk streams, from where it flows to the Thames to be captured into the London reservoirs. The scheme is used very, very rarely: no more than once every 25 years. But it’s there. And it guarantees water in a drought.

The West Berkshire Groundwater Scheme wellfield: this scheme is rarely used but guarantees water in extreme droughts. It is a counter-intuitive idea that could unlock abstraction reduction in the Colne, Lea and Ouse chalk streams.

The impacts on the chalk streams are a) one of flow relief in the drought, because the flows get boosted. Albeit – and I have to emphasise this – flow augmentation in not the aim of the scheme, it is a bi-product. And b) at the end of the drought, when the pumps are turned off, the aquifer must recover before flows return to natural levels, so you get lower flows the following year.

But this is crucial: in modelled scenarios, the flows in the year of recovery are still better than they would be if abstraction ran all the time as happens at the moment in streams like the Ver, Misbourne and Beane.

So WBGWS type schemes could unlock Chalk Streams First type abstraction reduction in other settings, such as on the chalk streams of the Colne, Lea and Ouse (even the Darent). As such a scheme would insure against the public supply deficit in droughts created by replacing upper catchment groundwater abstraction with lower catchment surface water abstraction (the Chalk Streams First concept).

BUT …the Environment Agency is very cautious of such schemes

This is understandable because there have been some bad schemes in the past. But flow augmentation to compensate for the collateral damage of abstraction is a different thing altogether. 

Some schemes were developed in the past whereby to compensate for abstraction (which had dried the stream) water was pumped from the aquifer into a losing reach of stream and the whole thing was a highway to nowhere.

Other times the concept of augmentation is used to justify continuing, unsustainable abstraction. These schemes have given the whole idea of flow augmentation a bad rap, and one that has stuck like glue.

RevIvel claim that a flow augmentation scheme putting 0.5 ml/d into a dry river bed is not a good type of augmentation scheme, especially if it delays a proper solution to the unsustainable abstraction. This is the kind of scheme is very different from the idea promoted in this blog post.

BUT, I would argue that we need to be more pragmatic and open minded than a presumption against these schemes if we are to achieve the heretofore irreconcilable goals of reliable public water supply and restored chalk streams. Aquifers in the south east are managed one way or another. We need to make sure they are managed mindfully to achieve the specific outcomes we want and in this regard holding out for “natural” when a more flexible approach would unstick hopeful schemes such as Chalk Streams First would surely be counter-productive?

I understand the Environment Agency may be consulting on this topic later in the year. I know from many discussions I have had with chalk stream advocates that the ideas I have outlined above will be surprising and counter-intuitive to most of us, as indeed they are to me.

But it is vital we give the EA the encouragement to take a flexible, if ultra cautious approach, because the gains of doing so could be massive.

Prioritising abstraction reduction: we need common sense more than we need evidence.

Posted in UncategorizedTagged , , , , 1 Comment

It’s brilliant that the Environment Agency has, through the national framework, identified the flow deficits that exist on our chalk streams. 

It’s great that Environment Agency has signalled to the national framework groups that chalk streams should become a priority in terms of addressing those deficits.

Thus far, however, the Environment Agency has inclined to stand back – at least publicly – from guiding the decision-making that will be needed to apportion those abstraction reductions strategically and cost-effectively over time. This is being left to regional groups and partnerships, but it is not yet clear how these decisions will actually be made or if they will be consistent and logical.

Our CaBA chalk stream strategy called for the collaborative development of a prioritisation process and while everyone agrees the need, it still hasn’t quite happened.

In all of the meetings I have ever attended in which abstraction reduction is discussed the idea is aired that we will need evidence to justify and ensure wise decision-making, including evidence that ecological gains will follow mooted abstraction reductions.

On the face of it, the call for evidence seems only prudent and sensible – after all public money is at stake. 

But the idea that such evidence could ever exist is a chimera.

Clear cause-and-effect evidence according to a robust, before / after / control / impact method of proof, is – I argue – impossible to acquire. And it is so, precisely because of the infinitely complex web of cause and effect that is leant upon to justify the call for evidence.

Water companies will argue, and rightly, that reducing abstraction is expensive and, therefore, that there’s no point doing it if no benefit follows. Or if the potential benefit is neutered by some other factor such as a heavily modified river channel, or pollution from farms.  In certain settings we run a real danger of spending millions reducing abstraction, when other factors – like the fact that the river is navigable and impounded by locks and weirs – are as big or even a bigger brake on the ecological health of the system from which there is no possible relief. 

There are also settings where the cost of reducing (some of) the abstraction could be more cost-effectively spent (in terms of ecological gain per buck) improving the physical habitat. We have transformed canal-like channels in Norfolk into vibrant, wild and free-flowing streams for modest amounts of money, all things considered. £200,000 per km is dwarfed by the £4 million cost of replacing 1Ml/d of water. For that you could rebuild 20 km of knackered chalk stream.

I’m all for the intelligent and undogmatic trade-offs and counter-intuitive thinking that will be needed if we really are to balance the needs of society and nature.

But the call for evidence is self-deluding at best and a delaying tactic at worst.

Why? 

In the insanely busy and pressured landscapes we are talking about it is virtually impossible to strip out the variables: the physical condition of the channel; the micro and macro stressors of water quality which are highly complex and some of which we barely understand; shifts in the global agricultural markets which might generate or ease an agricultural pressure beyond one’s control or easy quantification; road run-off which might be terrible in a year when a local farmer is rearing pigs, or not too bad when the farmer gets rid of the pigs or in a mild, dry winter; the weather; the climate; the impact of invasive species like signal crayfish, or predation from cormorants when a cold winter forces them off the reservoirs: etc. etc. etc.

I defy anyone to design an experiment into the teeth of those variables, that could possibly isolate the beneficial or non-beneficial impacts over time of one single action. 

The only way you could construct such an experiment would be to select a stream where abstraction is pretty much the only pressure and a significant one, gather baseline data for at least five years, ideally a decade and then COMPLETELY TURN OFF THE ABSTRACTION in that stream and all nearby streams (because you need the signal to be significant to rise above the variables you can’t eliminate no matter how hard you try) and study for another five to ten years. The study periods would have to either equally include or exclude periods of drought and very wet years too. 

When helping to write Defra’s now scandalously abandoned chalk stream recovery pack, I was looking for exemplar case studies of where abstraction reduction had made a significant and demonstrable beneficial impact to ecology. I struggled to find a slam-dunk example, mostly because the reductions that have been made – though significant – have been made from very high totals and are actually quite small against the volumes still abstracted. For example, on the River Ver, while abstraction once exceeded 50% of recharge, it is still 30% of recharge.

This reach of the River Piddle used to dry regularly in the late 1980s early 1990s.

I cited the River Piddle in the end, even though the changes made there since the dark days of the late 20thC when the river dried up regularly, include flow augmentation as much as abstraction reduction. The Piddle, however, is indeed much better now than in 1989 – 93. I know because I’m lucky enough to co-own the bit that used to dry up and it is now an exemplar of chalk stream health. It is an example.

But even so, water companies and others will often say abstraction reductions made thus far haven’t yielded the hoped-for results. Either in terms of flow or clear ecological gains.

In terms of flows, this is not true. John Lawson’s analysis of the flow-recovery following abstraction reductions shows unarguably that flows do recover in proportion to abstraction reduction. But when the abstraction is really high and you only reduce it a bit … hmmm.

John’s report also shows that the reductions made, though significant and expensive in water resource terms, have been far too small relative to the size of the overall catchment abstraction and far too small to rise above the “noise” made by all the other variables (and many of these variables haven’t been attended to properly, either. We still have a lot to learn about high-quality and cost-effective process-based habitat restoration).

In the only really good long-term BACI type flow scenario that exists, flows on the River Ver reduced and then recovered exactly in sync with the abstraction increase and then reduction. Of course they did: where else would the water have gone to?

So, if slam-dunk cause and effect evidence that reducing abstraction Y will lead to X ecological recovery doesn’t exist and can’t be found, how do we approach the problem? 

Without knocking the idea that data and evidence are useful tools to guide our decision-making, we should not abdicate our own common sense. In the same way that we don’t need science to tell us that it’s warmer in summer (though we need science it to tell us why) we don’t need science to tell us that abstraction adversely impacts the ecology of a river (though we do need it to tell us why).

Many fine minds have spent a lot of time discussing and agreeing that sustainable abstraction in chalk streams should generally cause less than a 10% reduction in natural low flows, (which also, give or take, amounts to 10% or less of the average aquifer recharge). That is why we have the Environment Agency’s Environmental Flow Indicator, which is based on the UK Technical Advisory Groups deliberations on exactly this flow / ecology balancing act.

What we need beyond this work (that has already been done!) is not so much more impossible-to-find evidence but rather a screening process that aids and brings logic, common sense and consistency to the thorny issue of how to spend public money most cost-effectively in our collective goal of achieving sustainable abstraction on chalk streams. 

To give a really obvious example: we need a screening process that stops us spending billions of pounds reducing abstraction in a river that is navigable and therefore doesn’t really have a flow-dependent ecology, but compels us to crack on with spending millions of pounds reducing abstraction in iconic chalk streams which can also be physically restored for 200k per km!

That really shouldn’t be too difficult.

I have made a start below … comments welcome.

Screening flow-chart for abstraction reduction prioritisationDownload

The ‘shocking’ State of England’s Chalk-Streams 2014

Posted in chalk streams, conservation, events, river restorationTagged , , 6 Comments

_dsf3142
England’s chalk-streams: their shocking state is the ecological restoration opportunity of our time.

Last night I was invited to speak at the launch of WWF’s new report: The State of England’s Chalk Streams 2014. The report reveals that over three-quarters of these iconic and globally unique rivers are failing to meet targets for ecological health.  This is what I said to the audience at the South Bank Centre:

“I want to talk to you this evening about how the state of England’s chalk-streams – a state this new WWF report correctly describes as shocking – could become the most incredible opportunity for ecological restoration. We have the means and we have the knowledge to rehabilitate this broken ecosystem. All we lack is the will. But will is only a change of mindset. Minds can be changed.

In some ways this ‘shocking state’ is not surprising.

I’ve just spent five years researching a book looking for the reasons why, in 1965, a chalk-stream in Buckinghamshire called the River Wye was buried under the streets of the town it gave life to. The answers were on one level mundane and soulless: the river was buried to widen a road. On another they were as complex and layered as the history of the valley that river flowed through. Geology and industry and slum clearance and town planning stacked up one after the other, until the river’s burial became as inevitable as the construction of a shopping centre above it: a retail cathedral which the Council named Eden.

The world over the struggle between nature and man, between the stream and the street, ends with the incarceration of the stream. It’s not that anyone especially means rivers any harm. It’s just that through an ironic twist of history rivers give birth to and then get in the way of economic expansion. Swap street for field, the principle holds.

English chalk-streams flow through landscape at the epi-centre of Western civilisation: certainly in terms of the depth of its history, the density of its use. In other words, they are a globally unique eco-system in the very hottest part of the fire. Of course they’ve been pushed to the edge of existence. Looked at this way, it is a minor miracle that we have any chalk-streams left at all.

That river was buried to widen a road. It is worth remembering that this is how it happens. No-one is planning or hoping for a world in which there is no room for nature. But the end of the wet and the wild is death by a thousand cuts: none of them is actually mendacious, but all of them are careless.

And yet, this grim fact is also an exciting opportunity. If economic growth almost always leads to ecological destruction, it doesn’t have to. Making room for nature begins with seeing how it matters. So why do chalk-streams matter? Why should we care more? I can try to tell you why I care.

I grew up in London, but every other Friday night through the late 1960s and then the 1970s we drove north to spend the weekends in Norfolk. I had no particular idea then, as I struggled to peer out the car window, that the route we took, around the edge of the Chilterns, across the Hertfordshire downs, up the ridge of the Gog Magog hills all the way to the multi-coloured cliffs of Hunstanton, was more or less entirely across a chalk landscape. But towards the end of the journey, when the evenings were long in summer I would ask my father to slow down over one or other of the bridges which crossed the streams near our house. One was over a river called the Ingol, where it tumbled over a small waterfall beside a bus stop. Another was over an equally small stream called the Babingley. I adored these miniature brooks for a reason I could never have explained. They just spoke to me and I loved to spend a few moments watching them flow.

Now, forty years on, I know that these little brooks were chalk streams. I also know that we would have crossed others on that journey: the Colne outside Heathrow, and then that river’s Chilterns tributaries the Chess, Misbourne, Gade and Ver. Running north up the A1 we would have crossed the Lea and the Mimram and then, riding the ridges of those chalk hills we threaded between the Beane, Oughton and Purwell. Turning east we narrowly missed a few more – the Cat Ditch, the Ivel, the Hiz – before we crossed the Cam and then the Granta. Further on we crossed the Snail and then the Fenland incarnation of the Lark. Then the Little Ouse, the Wissey, the Nar, and finally, nearing home, we crossed the Babingley, the Ingol, the Heacham and smallest of all, the Hun.

Those 24 names represent a good proportion of all the chalk-streams that exist globally: about one-eighth of those in England, whose total of a little over 200 streams – varying in size from the stately River Test in Hampshire, to diminutive little brooks you can almost hop over – make up most of the chalk-streams in the world. There are a number of chalk-streams over the channel in Normandy. But further afield, although there are great swathes of chalk across Kaliningrad, Bulgaria, Czechoslovakia, or the Ukraine, although there is chalk in Texas, Israel, Egypt and Australia, it seems that there just aren’t any rivers like the English chalk-streams. Ours appear to be almost unique.

To understand why you need to think of Europe as … well if you’re into cooking think of a layered cake and if you’re into DIY think of plywood. I’ll go with the cake metaphor …

… the chalk is just one layer, the white sponge say, sandwiched between layers above and below. Now, imagine you tilt the cake so the layers no longer lie flat. Now, squeeze it from each side so the whole cake buckles. Finally take a knife. This knife is made of time and ice and rain and wind. Run the knife across the top of the cake: but don’t be too careful about taking a neat, even slice. The knife, you’ll find, slips more easily through the softer layers, the cream, the fluffy sponge; but it struggles a bit at the toffee and caramel. It all gets a bit messy of course: the cake you have cut away, some of it dissolves, while some of it is spread across the surface elsewhere. This layered, tilted, buckled and untidily sliced cake that you have imagined is the surface of the earth. The layers of rock, the layers of the cake, show at the surface in bands. In places the bands are smeared over with the remnants of other layers. In places they stand clear. The layer of white chalk at the surface in the Chilterns, for example, has been cut away and is long since gone from over Scotland; it lies intact but deep under the surface of eastern France; and in Bulgaria, while it might be more or less at the surface, it is covered with great smears of other stuff.

This is why most chalk-streams are English. Chalk-streams only flow where that soft, soluble white rock protudes at the surface, and more to the point, where it is relatively uncorrupted by the marbled mess of depositions left behind by the knife.

And what is this chalk? It is the fossilised remains of infinitesimally small sea creatures which swarmed millions of years ago in pre-historic seas. Most of Europe was once under the sea. Chalk formed at its edges where countless billions of dead coccoliths rained down to the ocean floor, settling and compressing into a porridgy ooze, which became in time, chalk. It took a while: the chalk accreted at a rate of one millimetre a century, one centimetre every thousand years. And now we have our chalk hills: a great belt of them in England that runs from south-west Dorset, past London, through East Anglia and up into the Yorkshire Wolds. Some of these hills are hundreds of meters thick.

Chalk-streams, like most rivers, begin with rain. But when rain falls on chalk it sinks into the ground through fissures and cracks, or it soaks into the body of the chalk itself, turning the hills into underground oceans of trapped water. A drop of rain might travel five miles or 50 under the earth, it might stay down there five months or five years or five centuries. The subterranean topography that determines exactly where the water goes is immensely complex, almost unknowable.

What we do know is that here and there, in a wet furrow in a meadow, or under the roots of an ancient tree, or in a rook-filled copse on the edge of a hill, that water re-emerges as springs – and that in these special places chalk streams are born.

What flows from the spring is no longer plain rainwater, however. It is chalk-water: cold and clear, and rich in minerals. The steady flow of this cool, fertile water in meandering, gravelly channels creates spectacularly diverse ecosystems. The unspoilt chalk stream is like a watery Garden of Eden: chequered beds of water crowfoot swaying in the marbled currents, constellations of white flowers, vibrant green beards of starwort and clouds of water-parsnip; the banks decked in marsh marigolds, water mint, and flag iris; under the surface brown trout and grayling, young salmon and sea trout, white-clawed crayfish, freshwater shrimp; in and over the plashy meadows, snipe and otters, water voles and mayflies.

But chalk streams are special not just in their geological origins, and the wonderful ecosystems this creates. No river on Earth is as much a product of human as well as natural history. They are such gentle, malleable rivers. They have been harnessed and lived with for thousands of years, shaping and shaped by human history in one of the most used landscapes anywhere in the world. Think of the Roman villas, the mills, the medieval priories and holy houses, the castles, the ornate Palladian parks and gardens, the fisheries, the Georgian water meadows. All these things give chalk streams a distinct beauty that is not the same as the sublime, unpeopled beauty of craggy peaks and spouting waterfalls. Chalk streams are home-spun and life-giving. Chalk streams are pastoral. Chalk streams are living, flowing history.

This intersection of geology and geography, of climatic history and finally human history has created a unique type of river: Edenic, life-giving. Chalk-streams are an English Okavango Delta, an English Great Barrier Reef, an English rainforest. Which ought to mean we should value this heritage as highly as we would any other globally unique eco-system.

Sadly, we don’t. Instead these unique rivers are abused: some to the extent that they have dried up and ceased to be rivers at all. Others are rivers in so much as they have water in them, but in every other way they are changed. Some are buried underground. Most are polluted too. To our shame most of the really debilitating changes have occurred in the last 50 or 60 years. Before that time chalk-streams were certainly much-used river systems, but our relationship with these rivers was to a large degree symbiotic. Since 1946 a fatal combination of dredging, diffuse pollution and water abstraction has made it parasitic.

Today, the range of threats is diverse and most are difficult to overcome in a busy, valuable landscape which also supports farming and industry, people and businesses.

Difficult to overcome, but surely – given the value of these rivers – not impossible?

Remember that river which was buried to widen a road? Now, fifty years after it was lost to the world, the Town Council is planning to unearth it again. The change has come because they believe it is possible and can see reasons enough to want to. The river will bring back the heart of the town. Like the rock that made the river, history took that stream underground and has brought it to the surface again. All it takes is will. A change of mind. A different way of valuing things.

There are two ways to look at this struggle between man and nature, between environmental growth and ecological destruction. Either we sacrifice the places where we live and work and try to pickle the places we don’t: which won’t save them, by the way, because they too will shrink until there’s nothing left.

Or, we learn to make room for nature and create a world where unique eco-systems can exist alongside or even inside functioning, economically viable landscapes. It is that polar choice which makes the sobering state of the English chalk-stream the most tremendous opportunity. If we can make that room here – and I know we can – we set an example for the rest of the world. We create a beacon of hope.

If we can do this in this busiest of landscapes, we can do it anywhere.

If chalk-streams are our burning rainforest, it is up to us to put the fires out.”