Jargon busting the Chalk Streams First letters:

I’ve recieved a friendly moan from an old friend that our letters to Water Resources South East (WRSE) and Affinity Water are unintelligible and therefore difficult to support.

As someone who is passionate about using plain English and trying to write simple, accessible prose I feel a bit embarrassed to receive this fair complaint. The submissions were to specialist audiences at WRSE and Affinity and they will be more than familiar with all the contents. But the average chalk stream fan won’t be. So, while I don’t intend to change the letters, a bit more content and explanation may well help you to endorse them.

Water Resources South East (WRSE) is one of several regional groups tasked by Ofwat (the government appointed watchdog of the water industry) with developing plans to build resilience of supply (making sure we don’t run out of water) and environmental protection into our national water-resources infrastructure (the abstractions and pipelines and reservoirs that bring water to your tap) over the next 50+ years.

This is the best opportunity we’ve ever had to ease pressure on chalk stream abstraction.

WRSE has developed a draft regional plan which is out for consultation with the general public: this is where you get a say in the priorities and thinking behind the plan. The deadline for responding to this consultation is the 20th February. LINK HERE.

In addition there are the water company WRMPs (water resource management plans) which deal with the application of the WRSE work in each given water company area. Again, the deadline for responding to the Affinity Water WRMP is the 20th February. LINK HERE.

I won’t deal with everything in these plans, but specific to chalk streams and especially Chalk Streams First (CSF being a proposal to reduce groundwater abstraction in the chalk stream tributaries of the Colne and Lea and take the water from the lower river instead after it has flowed down the chalk streams) the following should help you understand what we have said:

Prioritisation (where abstraction reductions will happen)

The WRSE plan has taken on board our ideas of prioritising abstraction reduction in the chalk stream tributaries. This is good news and we support it.

However, the WRSE “environmental deficits”(ie. the amount of water we should cease taking from the environment) in the most ambitious versions of the planning, are massive: so large it is difficult to envisage where all the replacement water will come from. These deficits have been arrived at through the application of Environment Agency flow targets on every single water body without, thus far, any published detail to draw distinctions between places where the ecological need is urgent and places where it isn’t.

Given that all water comes from the environment somewhere, the problem with this lack of prioritisation is that we could easily end up creating environmental problems in one place whilst trying to fix them in another, or we could end up not fixing them in a place of great ecological importance by protecting a place of lesser ecological importance.

We think this prioritisation has been slow to develop because it is a very difficult decision-making process. It must be done, however, or we will not achieve value for money, or even the right outcomes, in our attempts to restore and protect the environment.

Demand reduction (each of using less water)

Using less water is a really obvious way to ease pressure on the environment. Currently we use at least 33% more per head than we should: 150 litres per person per day versus a target of 100 – 110 litres per person per day. It’s easy to use too much water when you have no idea how much you are using: you just get complacent. On the other hand, incentivising people to use less water is very tricky: you rely on the full time application of a conscientious approach, which is tough to keep up.

Evidentially, by far the best way to get people to use less water is to fit a smart meter to the house: if people can have sight of how much they are using and how much it is costing them, and how much they could save by using less, they will use less. Simple as.

The government has now allowed for the designation of any chalk stream area as “water stressed”: this means water companies can roll-out compulsory smart metering.

We think they should get on with it as fast as possible.

New sources (finding new water)

The WRSE region is especially stressed because there are just too many people versus too few raindrops in south east England.

Whilst smart meters and leak reduction can help address a large chunk of the deficits, the results from both of these programmes are uncertain.

To ease pressure on the environment and address these flow deficits (as above) we also need to find new water from somewhere, ideally without creating another environmental problem in that other place.

Therefore, we believe the best and most certain way to ease the burden on the chalk streams in the WRSE region is to transfer new water into the region. And the best way to do this without creating a flow problem somewhere else is to transfer water that is “going spare”, so to speak.

GUC (Grand Union Canal)

The most obvious and massive source of water that is going spare is the 400 Ml/d (millions of litres per day) that comes from the Minworth sewage works outside Birmingham. Water that currently swells the flows of the Tame well beyond anything that would have flowed down it naturally, because this water ultimately comes from Wales (through Birmingham), where it rains a lot more than in the south east (and where there are fewer people).

There is also an easy way to get some of that water in to our region, via the Grand Union canal, which for Phase 1 (50 Ml/d by 2030) requires only a modest amount of extra work. This is a no-brainer. Everyone agrees it is. And so we support this transfer fully.

We would also like to see Phase 2 brought forward, so that there is less reliance on the uncertain leak and demand reductions. Not that these aren’t important measures, but they are at best, uncertain.

T2AT (Thames to Affinity Transfer)

Another component of these water transfer schemes that could help ease the burden for chalk streams is a pipeline called the Thames to Affinity Transfer, T2AT (aka Supply 2050). This pipeline would allow any recovered flow that comes from a result of dialling down chalk stream abstraction to be captured in the lower catchments and used to supply the places formerly supplied by groundwater abstraction.

Supply 2050 was once called Supply 2040. When we launched the Chalk Streams First idea we asked for it to be brought forward and called Supply 2030. So, moving it back is the WRONG DIRECTION OF TRAVEL and threatens to delay the recovery of the chalk streams by decades.

Therefore we have objected to this and asked for the Thames to Affinity Transfer to be brought forward.

The delay appears to be based on an Affinity Water estimate that the flow recovery from the chalk stream abstraction reduction (how much of the water you leave in the ground which comes back as surface flow) will be only 17% at low flows and during droughts. Therefore, they appear to be saying that we need a large SRO “strategic resource option” like Abingdon reservoir, or the Severn to Thames transfer, to underwrite the abstraction reductions.

Thames to Affinity transfer, therefore, is currently linked to the construction of Abingdon / Severn to Thames.

Chalk Streams First has no problem with either of these schemes, but strongly objects to the idea of linking chalk stream abstraction reduction to them, as it will delay everything.

We don’t agree with the overly precautionary 17% flow recovery estimate. Our own research suggests the flow recovery will be much more like 50%, as it was during the average flow percentiles that existed for the duration of the two worst droughts in the past 100 years (1921 and 1933/34) (these drought are used as benchmarks for planning).

That’s why we have asked for T2AT to be brought forward.

Groundwater Insurance Scheme

Although we don’t agree with the 17% figure, we do accept that there is uncertainty. No one knows for sure how much flow comes back at given times. The best way to insure against this uncertainty is a groundwater insurance scheme.

This is a tried and tested idea: there is one in existence called the West Berkshire Groundwater Scheme. It is used very occasionally (designed for use every 25 years or so) to pump water from the deep storage of the chalk aquifers of Berkshire into streams like the Pang, where it flows down to the Thames and feeds the London reservoirs during droughts, when they are running out of water. It adds 90 Ml/d to London’s supplies. That’s a lot.

But it is a counter-intuitive idea because it involves abstracting from the chalk in a drought!


For reasons that I have tried to explain HERE that actually doesn’t take water from the flow at the time, but instead creates a debt to future flows. This is because there is a time-lag between the abstraction and the impact. By the time the impact hits the winter flows would aid recovery.

Besides, you use the chalk streams to deliver the water.

So, the net impact is actually enhanced flows during the drought and lower flows than natural the following year. However, even through the flows would be lower the following year, they would still be much higher than if we carried on with the current abstraction regimes.

In other words the scheme allows you to dial down abstraction to a minimum most of the time, knowing that you have an insurance fall-back to help water supplies in a drought.

Its a total no-brainer in our opinion and we have asked for an urgent investigation into the viability of the scheme in the Colne and Lea catchments if it means we can get on with dialling down groundwater abstraction to the minimum level as soon as possible.

What does rheophilic mean?

rheo = flow / philic = loving.

Salmon, trout, ranunculus, blue-winged olives etc. are all rheophilic. Natural chalk streams have rheophilic ecologies.

But George Orwell would have always written flow-loving in the first place!

I hope all the above helps. Any more questions … just ask!

Chalk Streams First response to the Affinity Water WRMP consultation

Here is the Chalk Streams First coalition response to the Affinity Water WRMP consultation. It has been put together in consultation with all the groups in the coalition.

We are publishing our response ahead of the deadline (20th Feb) so that any individual or group can adapt or quote our collective position in their own response.

Some of the recent posts on this blog help to contextualise the content of our response: see, for example “Something We Should All Agree On”, “The Green Elephant in the Room” and “Flow Recovery Following Abstraction Reduction”.

Find out more about the Affinity Water WRMP on this link HERE

The CSF report into flow recovery following abstraction reduction referred to in our response is available via a link on THIS PAGE or directly HERE

Chalk Streams First response to the WRSE draft regional plan consultation

Here is the Chalk Streams First coalition response to the WRSE draft regional plan. It has been put together in consultation with all the groups in the coalition.

We are publishing our response ahead of the deadline (20th Feb) so that any individual or group can adapt or quote our collective position in their own response.

Some of the recent posts on this blog help to contextualise the content of our response: see, for example “Something We Should All Agree On”, “The Green Elephant in the Room” and “Flow Recovery Following Abstraction Reduction”.

Find out more about the WRSE regional plan on this link HERE.

The CSF report into flow recovery following abstraction reduction referred to in our response is available via a link on THIS PAGE or directly HERE

Flow Recovery Following Abstraction Reduction

Pictured above: the flow gauge at Redbourne on the River Ver. It may not look like it sometimes but following a significant abstraction reduction in 1993 at Friar’s Wash on the upper river, an average of approx 80% of the water returned as surface flow. The River Ver, however, is still heavily over-abstracted.

The Chalk Streams First coalition has CSF has commissioned an independent investigation (CLICK HERE) into flow recovery following abstraction reductions in the Colne and Lea chalk streams.

This is an important piece of work because currently overly precautionary and unrealistically low estimates of flow recovery are shaping WRSE and Affinity Water plans.

Everyone acknowledges that if you switch off groundwater abstraction a lot of that water comes back as river flow. Not all: some stays under the ground as aquifer throughflow. But about 80% on average comes back as river flow: known as flow recovery.

The flow recovery is not evenly distributed through the year, however. You get a much higher % back at high flows than low flows (see my post “something we should all agree on”). The return at low flows becomes critical, because this is the time when London’s supplies are most threatened and under stress.

Therefore, it is useful if we can find extra water to underwrite the lower returns you get at low flows. And of course, quite how much you get back makes a big difference to cost.

We need about 150 Ml/d to re-naturalise flows in the Colne and Lea chalk streams. And that has been recognised in WRSE plans. So far, so good.

Currently the Grand Union Canal transfer is set to underwrite about 50Ml/d of reductions by 2030-ish. Also, so far, so good.

BUT … the majority of the proposed reductions are not scheduled until after 2040 and are framed as being dependent upon a large strategic resource option such as either the Abingdon Reservoir or the Severn to Thames transfer.

This would push the ecological recovery of the chalk streams decades down the line. We think that is a really bad idea. And unnecessary.

The contingency / delay appears to be based on an estimate of 17% flow recovery from chalk stream abstraction reduction at very low flows, Q95 – Q100, meaning the strategic resource is necessary to underwrite the abstraction reductions. The 17% figure derives from a triangulated process of analysis conducted by Affinity Water and consultants, summarised in Technical Appendix 5.6 “Deployable Output Benefits from Abstraction Reduction”.

Our independent investigation into flow recovery from abstraction reductions suggest that the 17% figure is unjustifiably conservative and that average flow recoveries at the relevant percentiles are considerably higher: in the region of 50% to 60% of upper catchment reductions translates into increased deployable output in downstream reservoirs at the average percentiles through the 1921 and 1933/34 droughts.

The delay in implementing the reductions is therefore unnecessarily precautionary.

It’s a long report, so maybe just read the summary. Once again, it is really important that as many of us as possible get our heads around the nitty gritty of all this, so we can be well informed in our discussions with the water companies, WRSE, the EA and government.

The “Green Elephant in the room” is really a straw man in the room

Picture above: The “River” Beane. For much of the time it is not imaginarily dry. It is actually dry.

Just before Christmas I published a long post that few people will have chewed through: my responses to some of the points Rob Soley, technical director at WSP, made in a webinar about abstraction reductions and his view that it is unwise for the UK to “abandon” groundwater abstraction.

Rob has followed up that webinar with a feature in CIWEM magazine entitled “Enormous Cuts to Groundwater Abstraction in England are Unwise”. Rob is an eminent hydrogeologist. His arguments will be taken seriously. Some of what he says I fully agree with, certainly the need to prioritise abstraction reductions so that we get the best ecologic outcomes for the investments.

But as with the webinar, we have to unpick the reasonable arguments from parts that are hyperbolic and alarmist, arguing against the most extreme interpretations of the new ideas. No one is about to turn all these pumps off. There is a reasonable debate now – and not before time – about how to realign water resources and ease the pressure on the environment. As is the nature of debate, there are various points of view. We need to find common ground. Common ground is not the status quo.

The water industry and its army of hydrogeologists must accept that groundwater abstraction has caused and is continuing to cause significant ecological damage to precious habitats in chalk streams around London, into Kent, Cambridgeshire and Bedfordshire. This are where the environmental pressures are at their apex and they are massive.

The NGOs, and river groups need to accept that the public needs water, Water Cos have to supply it, that it has to come from somewhere and that therefore we do need to engage in a pragmatic discussion about compromise and priority.

Rob’s argument is essentially that through a laudable but deluded greenwashing project we are in danger of losing sight of a formerly more rounded definition of “sustainable” water resources, which should include a consideration of fact that we currently enjoy relatively inexpensive and clean chalk groundwater with tolerable ecological impact, versus the costs to society of developing alternative sources (should we do that), the carbon impact of transporting water, and the disappointing ecological outcomes that are likely to follow all that (unnecessary) investment. He characterises this project as the green elephant in the room.

This is a somewhat polarised way of seeing things and I suggest that the problem at the heart of this polarisation is the sheer size of the abstraction reductions which have been put to the regional groups without much attempt, thus far, to really distinguish between them in terms of priority. The deficits were calculated using the EA’s EFI methodology, and applied to every single water-body, without distinguishing between whether the water-body was a vulnerable, headwater chalk stream, or the navigated, impounded and discharge-supported lower reaches of a large, urban river.

This is ringing alarm bells for water companies and their consultants. But Rob is taking arms against a straw man.

At least Chalk Streams First is not arguing for the scale of abstraction reduction Rob takes issue with. But we are arguing for the restoration of flows to streams like the Ivel, Ver, Chess, Beane, Misbourne, Rib, Darent, etc. In our submissions to WRSE and WRE we have argued for a transparent prioritisation process. And indeed the EA has taken note of this and some work is being done in the area.

That work needs to be made urgent now. Otherwise the debate will entrench and become this all or nothing dichotomy in which I am certain the environment will lose out. After all money trumps ecology every single time and if the bill can be characterised as foolhardy and massive, it won’t get paid.

One example: the total deficits for the whole Colne system down to the Thames amount to 270Ml/d. That’s a lot of water. Two Abingdon reservoirs of deployable output. The total deficits on the chalk stream tributaries, however, amount to about 80 Ml/d. Factoring in a reasonable expectation of 50% flow recovery (see my previous post) at low flows, that leaves a net deficit of 40 Ml/d. This can be cheaply provided via the Grand Union Canal transfer.

If you add to this the idea of a groundwater insurance scheme, the net deployable output to London actually goes up.

The lower Colne, which makes up the bulk of that enormous 270 Ml/d deficit, is highly modified, embedded in a stable water-table, much supported by discharges and would benefit from the all the chalk stream flow recovery anyway.

There are intelligent ways to do this, in other words. Ways that are not all or nothing, but consist of pragmatic and measured improvements that are well worth paying for.

Something we should all agree on.

Pic above: The River Ver in the drought of 2022. And the million dollar question: how much flow do we get back if we turn off abstraction?

Making Chalk Streams First a reality: how do we overcome the uncertainties?

A few months ago the Chalk Streams First group commissioned a follow-on report from John Lawson, to investigate and collate evidence of flow recoveries following abstraction reductions in the Chilterns and Herts chalk streams. The report is now finished and we will publish it soon. 

The blog post below introduces some of the complex discussions in the report. It leads to an important proposal for a type of scheme which traditionally the conservation community has been wary of, but which is well worth considering in the light of the debate over flow recovery. 

It could help to address water-supply resilience and ecological restoration and thus allow the full delivery of Chalk Streams First within a few years as opposed to a few decades.


If I was to say “abstraction has a much smaller impact on chalk stream flows at low flows and in times of drought, than it does at high flows and in winter” you’d probably furrow your brow. 

Everyone does.

The explanation is actually found in simple physics. But it’s counter-intuitive and so not easily understood, and because of that, not generally known.

But it is really important that we get our heads around the idea, because otherwise we’re in danger of allowing the Chalk Streams First project, and especially the potential pace at which it could be realised, to be derailed. And we’re in danger of missing the clear benefits of a groundwater scheme that could bring all parties together.

With a surface abstraction from a river, it’s easy to see the link between abstraction and flow. The river is flowing at X Ml/d. You insert a pump into the river and pump at a rate of Y Ml/d and the flow d’stream of the pump will become X – Y Ml/d. 

As the flow in the stream diminishes through the summer, Y will become a larger and larger proportion of that flow. And vice versa, it will become a smaller and smaller proportion of that flow through the winter. Therefore constant surface water abstraction has a BIGGER impact on low flows than high flows.

And yet most groundwater abstractions – and certainly groundwater abstractions at a catchment scale – seem to have the opposite impact: a smaller impact on low flows than high flows.


The reason is bound up with the fact that once you abstract water from the ground and not directly from the river, the impact on flows is no longer direct either, but occurs via the impact on groundwater level. Thus the impact is bound to the relationship between groundwater level and flow, because it is groundwater level – the head of the groundwater level above the bed of the river – that drives flows into chalk streams.

Just as the rate of flow out of a hole at the bottom of a bucket increases as the level of water in the bucket rises, so the rate of flow from an aquifer into a chalk stream rises as the groundwater level rises. The force that drives the flow is gravity or hydraulic head.

But it’s not just hydraulic head that places a cog in the link between groundwater level and flow. There are the properties of the rock matrix of the aquifer – how much water it holds and where and how quickly that water can move – as well as the topographical shape of the valley. And there’s time too. 

All of these combine to create a non-linear relationship between groundwater level and flow. Which means that for each unit rise in groundwater level, you get an exponential increase in flow. The aquifer, its topographic features and time provide gearing, if you like. 

So, if a rise in groundwater level from, say, 98 to 99 AOD gives a much greater increase in flow than a rise from 95 to 96 AOD, it stands to reason that a reduction in groundwater level from 99 to 98 AOD, will cause a much greater reduction in flow than a reduction in groundwater level from 96 to 95 AOD. 

Same unit rise or fall, but a bigger or smaller net reduction in flow.

Abstraction has an overall lowering effect on groundwater level. Therefore, one can see that the overall effect will have a bigger impact on flow when groundwater levels and flows are high, than when they are low.

The implications of this, when combined with water resource considerations, are significant.

We’ve always said, when pushing the case for Chalk Streams First, that if you switch off abstraction you get, on average, about 80% of the water back as surface flow. We’ve also always said that % flow recovery varies through the year, with over 100% in winter and as low as 30% or so in late summer (when groundwater levels are lower). In very low flows (Q99) this recovery might drop to only 20%.

This is where TIME comes in. The abstraction rate was constant, but because of aquifer gearing, the “less” you get back in the summer, actually comes back as “more” in the winter and you have to take a long view to see that over the full year the amount of water you get back is about 80% of that former abstraction rate (the remaining 20% passes through the aquifer under the ground).

Obviously these figures vary stream to stream.

It is the figure at low flows that is key, because it is low flows and especially 18-month droughts, that threaten water supplies in and around London. 

In the current drafts of Affinity Water’s & Thames Water’s water resource management plans, and the WRSE national framework plan, the estimate of flow recovery at low flows is a conservative 17%, where we think the figure should be over 50%.

The critical droughts used for planning purposes are the 1921 and 1933/34 droughts. The WRMPs are built around the basis that flows in these droughts averaged at the 98th percentile. In fact, from the beginning to the ends of these droughts flow averaged the 95th and 89th percentiles respectively, a combined average of the 92nd percentile, at which flow recovery from the Chilterns chalk streams – in our estimation – would be over 50% of the abstraction reduction.

The knock-on effect of planning according to that – in our view – irrationally low figure of 17% is that the lion’s share of the Colne / Lea chalk-stream abstraction reductions have to wait for a very large strategic resource option such as Severn-to-Thames Transfer or Abingdon reservoir. That pushes them back until after 2040. 

Can we really wait two more decades – and probably longer – for the full restoration of flows to our beleaguered chalk streams? In our view we could see most of the very much needed abstraction reductions far sooner. 

Part 2. The way round this which we could all agree on and act now.

Despite our differences of opinion over flow recovery, we can probably all agree that there is indeed uncertainty over the % flow recovery we will see at low flows. 

Therefore, from all points of view it is surely best to investigate ideas that overcome this uncertainty, ideas that might ensure the resilience of public water supply – as that is the issue of greatest concern to Affinity and their primary statutory duty – and also fully re-naturalise flows in the chalk streams, within a reasonable time-frame, not 20+ years.

The original Chalk Streams First idea was designed as a pragmatic solution to the formerly irreconcilable tension between public water supply and the ecological health of chalk streams near London. It always depended on storage because of the differing levels of flow recovery you get through the year. Now, with flow recovery at the very lowest of flows identified by planning constraints as the limiting factor, it is surely worth exploring additional ways to insure against these uncertainties.

Minworth – GUC transfer.

Water transfer from the Minworth sewage outfall via the Grand Union Canal is one such idea that has been universally accepted as worthwhile: it is in the WRSE and WRMP plans and of itself covers off a proportion of the abstraction reductions needed to restore natural flows to the Chilterns and Herts chalk streams. But it isn’t enough.

Licence Relocation

Rolling the groundwater abstractions down the catchment is another such idea: this came from Affinity and is a version of the Chalk Stream First concept. If the abstractions are sited down-catchment, where there is always perennial flow that vastly exceeds the pumping rate, much supported by discharges, then it is likely that stream-side groundwater abstractions will have an almost 1:1 impact in the same way surface abstractions do.

Groundwater Insurance Scheme.

In spite of both ideas above being no-brainers and enjoying universal support, the full-fat version of the Chalk Streams First proposal is presented as dependent on another large strategic scheme, such as Abingdon Reservoir or the Severn-to-Thames transfer. The Chalk Streams First group sees both as potentially important components to help ensure resilient water-supplies, but we would be extremely and justifiably disappointed if the full realisation of Chalk Streams First was made contingent on these either or both of these schemes. It would push the ecological recovery of these chalk streams decades down the line.

Therefore a third idea, tried and tested elsewhere, and worth exploring in the context of the Colne and Lea, would be a version of the West Berkshire Groundwater scheme (WBGWS).

Once it is understood that abstraction at low flows has a much smaller proportional impact at the time*, then it can be understood that something like the WBGWS has the potential to guarantee drought supply with a minimal ecological impact. This guarantee then underwrites the whole Chalk Streams First concept because the limiting low-flow recovery is underwritten.

(*Important to contextualise this “smaller” impact: where abstraction runs at 25 – 50% of recharge, as it does in the chalk streams around London, this “smaller” difference can still be the difference between flow and a dry river).

The West Berkshire Groundwater Scheme (WBGWS) was constructed in the 1970s to augment London’s water supplies during severe droughts – its planned use is about once in 25 years. The scheme abstracts water from boreholes in the chalk aquifer in the upper Lambourn, Pang, Enbourne and Loddon valleys, discharging water into those rivers from where it flows down into the River Thames for later abstraction to fill London’s reservoirs. It contributes about 90 Ml/d to London’s deployable output. 

The groundwater outfall on the Winterbourne tributary of the Lambourn, part of the West Berkshire Groundwater Scheme. A scheme like this on the Colne / Lea could underwrite all the abstraction reductions suggested in Chalk Streams First.
© Des Blenkinsopp

The WBGWS concept could be used in the Colne and Lea chalk tributaries, in combination with current proposal for reduced abstractions for day-to-day supplies. Replacement supplies would be transferred from the London supply system using the Thames to Affinity transfer and the ‘Connect 2050’ pipe network. 

Our initial assessment of the WBGWS concept in the Chilterns chalk streams has shown that on the River Ver a reduction of abstraction from the current 28 Ml/d to about 8 Ml/d, combined with WBGWS-type drought support of up to 25 Ml/d, would almost re-naturalise River Ver flows and also give a net increase in London supplies of about 9 Ml/d. 

If the concept was adopted in all the Colne and Lea chalk streams, abstraction could be reduced by 150 Ml/d to meet EFIs throughout the catchment. The 50 Ml/d first phase of the GUC transfer is a no-brainer, so only 100 Ml/d of replacement needs to come from the connection to London’s supplies. 

If the deployable output recovery of London’s supplies from the 150 Ml/d reduction is the 50+% that we predict, the concept gives a 50-60 Ml/d gain in London’s supplies. If the DO recovery is only 17%, the concept would still allow the 150 Ml/d chalk stream reductions to take place without impacting London’s supplies.

The drought support would only be needed about once in 25 years. Drought flows in the chalk streams would be increased by the WBGWS-type releases and would be slightly less in the following year but importantly, they would still much more than with abstraction at recent levels. 

This would remove much of the doubt that currently exists over the amount of flow recovery from abstraction reductions. A net gain in deployable output of 55-60 Ml/d could make this a significant new water resource in its own right. 

Why have schemes like this traditionally been seen as a “bad thing” by conservation groups? An incomplete appreciation of the gearing of impact must be one reason. Another may be an ideological aversion to the active management of a natural system. But all aquifers in south east England are managed to a degree: better by far to manage them intelligently to suit all desired outcomes. A cynicism about schemes which are usually proposed by water companies might be another reason!

Let’s put all these aside. Surely we need to engage in serious discussion about this idea?

Chalk Streams First appears to have brought all parties together: Ofwat, the water companies, EA and the NGO’s. But in the current draft plans it’s pace of instigation is still too slow / and the full version is at best uncertain.

The GUC transfer is a must have – so please support that in your responses – but let’s ask for a serious investigation of the groundwater insurance scheme too.

Much credit is due to John Lawson for the many, many hours of investigative work he put into the ideas I have summarised above.

Dredgers in Paradise

One of the dangers of best-kept secret rivers is that they are more easily trashed. I have long known this, and more than once before have had to open up on the name of a beautiful stream that I enjoy walking and fishing in order to shout loudly how important it is.

I’ve not done this in New Zealand before, however, have not ever felt it was my place to. And I know that Kiwis, fishing guides especially, don’t like the names of their secret spots broadcast far and wide. So, I’ll keep the name of this place quiet for now – if you know it, you’ll know it – at least until I can find out more about the reasons behind what I saw yesterday.

Because yesterday, I felt like giving up. I was totally in the dumps. The struggle to champion the cause of pastoral spring streams (chalk streams being in that group, and at the very apex of pressure caused by humans) feels too much like an uphill one at times.

I’m on a tour of New Zealand with Simon Cain – also a passionate river-restorationist who I have known since 1991 – showing him all the unspoilt spring-creeks I have been going on about for so long, the rivers I like to model river restoration ideas on. I told him the stream we were going to look at was one of my favourites: “It’s kind of like the upper Frome,” I said. “Only maybe a 13th century Frome.”

You could pick all sorts of holes in my comparison. There were no mills on this stream. There are no mountains to the side of the Frome. But it painted a picture. And indeed this stream has also worn the impact of farming quite heavily in places, over the years. It is abstracted by pumps. One farmer on it makes no effort whatsoever to fence out the livestock and the riparian edges in that reach are nibbled and puddled bare. The very headwaters, which were once a marsh supporting the base-flow, have been arterially straightened in the past.

But somehow the river was still just lovely. And I have often cited the lowermost farmer – when chatting to other farmers, many of whom are not that happy about the new NZ law compelling the fencing out of livestock (it is causing problems with overgrowth of rank marginal vegetation) – as having managed the riparian strip to perfection ever since I had known the place and long since before the new law: a fence twenty to fifty meters back and very occasional grazing on the stream side. He had presided over a true spring-creek paradise.

Which is why I suspect the farmer here is not to blame. Why, having been apparently perfectly happy for many years with the co-existence of his farming and his spring-fed stream, would he suddenly take a hatchet to the latter and hack it to bits?

We noticed the silt on the bed as soon as we arrived, noticed spoil on the bank by the first pool: rocks and stones and dusty, ex-riverbed the colour of light earthenware under an unnaturally vivid green flush of nettles and docks and thistles: all the stuff that loves the arrival of river-bed nutrients on top the of the floodplain where they don’t belong.

My thought was a resigned “that’s a shame”. We were near a bridge and I know farmers do get a bit heavy handed with the digger around bridges, in a (usually misguided) effort to create greater conveyance of flow.

But then around the next bend we saw more of the same, only the digger had really gone to town here, pulling out the bed and inside point-bar, dumping it all up in the side. The work had been done only a few months ago and already the stream was notching its way back upriver. Already the stream – in other words – was demonstrating the utter futility and pointlessness of the works, because it was now eroding really badly, with the banks slumping in and drastically undercut because of the excessively steepened gradient.

This continued for bend after bend. Apparently as far as we could go and further.

I felt too miserable after a mile or so and we turned back.

Then I remembered the photos I had taken here in 2020, expressly to capture the morphological features of the stream: the meander shapes, the relationship between the water surface and the flood-plain, the gently undercut banks and point-bars. All of which were now screwed. I hunted back on my phone to February 2020 and tried to line up a few before-and-after images. But I struggled to find the correct alignment between the stream and the hills: at least until I realised that not only had they dragged out the bed of the river, they’d tried to cut the meanders out too.

I was still just about thinking it was the farmer’s work and I was trying to fathom the “why?”. I was thinking: “They’ve had massive floods and done all this in an understandable, but misguided effort to drop the river back inside the banks.”

We slumped back to the car and in an effort to cheer both of us up I said to Simon that we’d drive up the valley to another bit I know. Only when we got there Simon looked out the window and said: “They’ve fucked this too. Look at all the gravel!”

And indeed, “they” had. Whoever “they” are.

By now I was thinking: this is the work of a flood defence department. Our own versions did all of this and more in the UK and Ireland. Only flood defence departments are this dim, careless and – I hate to say this but – entitled. I’ve thought about that last word, whether it is justified here, as the first two surely are. And I think it is, because when you go in and radically alter an ecosystem like a spring creek, it is surely beholden on you to understand what you are doing and carry out the works so that they achieve the desired outcome and not simply wanton destruction?

NZ’s spring creeks are globally very special. There just aren’t many rivers like these and most have been messed around with. NZ’s spring creeks have (thus far!) been modified less than most and some not at all. These streams should be seen as a national treasure, not drainage channels.

Later, asking around in town, we discovered that there had indeed been floods. The golf-course had been underwater and so had stream-side houses … miles downriver of the spring-creek vandalism, mind. Riparian property where a river belongs. It all made sense.

Only a flood defence department would steepen the gradient upriver in an attempt to alleviate flooding downriver. Only a flood defence department would make far worse the very problem they were trying to fix.

The river will now try to tear itself apart in order to win back the material it needs to put itself back together. As it does so, the water will travel more quickly, and downstream floods will be more aggressive: they will rise faster and bring with them way more mud, silt and stones.

Rivers flood. The only way to control flooding is to control where it happens. You can’t stop it. Allow it to happen in certain places in an effort to ensure it doesn’t in others. This stream has a two-stage form anyway, with secondary terraces way back from the main channel: you have to let it flood out to these or you will send all the water in even more of a hurry to the very property you are trying to protect.

One optimistic note: this stream will self-heal. Unlike chalk streams, it has the energy and the material to do so. Provided it is left alone. Which is now a very questionable proviso, because the notching and erosion will unleash a process which will appear in the minds of the men who did the work, to justify it in the first place.

And so we struggle on “boats against the current, born back ceaselessly into the past”.

February 2020
January 2023: not quite the same spot but note the new channel to straighten the course, the notching, erosion and bank collapse.
February 2020
January 2020: note the straightening and the height of water against the bank on the r/h of image: maybe 40 cm lower.
February 2020
January 2023: I had trouble lining this one up, until I realised the bright green bit used to be the river, and they had taken the meander out.

More pictures of the destruction:

The long Christmas read: what do we mean by sustainable abstraction?

We spent for ever trying to pin this one down as a foundation of the chalk strategy and finally settled along the lines of: abstraction should not reduce chalk stream flows by more than 10% from natural at Q95 (generally late summer), albeit there’ll be places where a less stringent target is acceptable (lower reaches of larger streams that are very heavily modified) and also there will be places where – as targets are neared – habitat improvements could arguably make more difference to ecological health than the last few increments of abstraction reduction.*

(*worth mentioning here that there is an inherent issue with flow targets in chalk streams: where do you measure the impact, given it will vary as you go upstream? Chalk Streams First has proposed abstraction as a % of recharge figure (10%) as a simpler way to limit impact, partly to overcome this issue: this will become relevant further in to this post)

Now, the eminent hydrogeologist Rob Soley has opened Pandora’s sustainability box again and is questioning whether, in the environmental ambition of the draft regional plans, the concept of sustainable abstraction has lost its holistic inclusion of cost and human need and is too narrowly focused on flows alone. This is an important debate and it needs to include all of us. So, this will be a long blog post but a worthwhile read, I hope.

For a while after I joined the WRSE environmental panel advising on the draft regional plan I was completely lost in a sea of acronyms and diagrams of water resource scenarios that looked like the wiring plan of a 1970s Fiat. I didn’t really know what anyone was talking about.

But then one day Tom Perry from the EA produced a spreadsheet of proposed reductions in abstraction for the chalk streams of the Colne and Lea catchments and for me the discussion suddenly morphed from the abstract to the concrete. This was where wiring diagrams met the real world and I realised what a game-changer the regional planning process could be. 

For the first time we were looking at evolving our siloed, localised, groundwater- and gravity-dependent water-supply systems – which inevitably exert a large environmental impact where the supply/demand balance is most out of step – towards better interregional planning, transfer schemes, water recycling and future desalination. 

And not before time. As long ago as the mid 1800s a miller on the River Gade, whilst arguing with the Grand Union Canal and London Spring Water companies about the impacts their abstractions had on his stream* had suggested that the long-term sustainable answer to London’s water supply deficit was to transfer water from north Wales, where it rained a lot and where there weren’t many people. 

(*Impacts they denied, of course. Worth noting too how the GUC and LSWC recruited the best scientific minds of the day to advance their case and argue that, for example, the water came from an infinite subterranean source incapable of exhaustion and completely isolated from the surface!!)

Here we were, 172 years later, finally thinking about the miller’s sensible, but ignored, idea. Though it sounded dryly bureaucratic, I realised the national framework planning process had the potential to bring about truly significant improvements to our really heavily abstracted chalk streams. The deficits to acceptable flows identified by Tom and the EA fairly closely matched those indicated by our Chalk Streams First modelling. We were on the same page and we were talking about truly meaningful reductions. 

But Tom’s first schedule really only covered the chalk streams. Later, when I saw the more global figures for all rivers and waterbodies, I started to worry in the other direction: they seemed so massive. Not from a purely ecological point of view, of course, so much as from a practicable point of view. How on earth would we deliver reductions that amounted to almost 2,500 Ml/d – the more ambitious of the potential scenarios – in the WRSE region alone? And could leak reduction and demand management really take up all the slack until 2050?

To put that 2,500 Ml/d into perspective, Abingdon reservoir could potentially add 400 Ml/d to our regional output. 

To put that into another kind of perspective, the total deficits to acceptable flows across ALL of the 55 chalk-stream catchments which we identified in our CaBA chalk stream A%R report amounted – according to the A%R assessment methodology which is not the same as the EA flow-based methodology – to only 399 Ml/d (excluding the lowermost Lea and Colne) and even that included about 100 Ml/d from chalk streams in the south west and eastern regions. Overall, we had deliberately surveyed most of the chalk streams which we suspected to be under the greatest stress.

The danger seemed obvious: Ofwat would look at the cost of these ambitious scenarios, deem them unaffordable and throw the chalk stream baby out with the “enhanced scenario” bathwater. Although I sat on the WRSE panel, I nevertheless responded to the first iterations of the draft plans, stating the importance of prioritising these proposed reductions so that we didn’t mix the “essential” up with the “to-no-great-gain” and the importance of planning / delivering the reductions in such a way that the investment added up to conspicuous improvements. 

The last thing we want is to expend a great deal of effort and money to no great or obvious effect, undermining the case for environmental restoration in the first instance. It would be perfectly possible to. Arguably this is what has happened thus far, where abstraction reductions have been made in a piecemeal way, often offset by increases within the same catchments, so not actually amounting to net reductions at all, consequently allowing a narrative to develop that abstraction reductions don’t really yield much of an increase in river flows, or not one that you’d notice, or not one that is justifiable given the cost. 

Recently, Rob Soley has been leading a bit of a kickback campaign questioning the sense of the proposed reductions in the national framework. Of course Rob’s concern may include a worry that overblown / poorly planned abstraction reductions could run the danger of ruling ALL abstraction reductions out of court: but mostly Rob is worried about turning our backs on a valuable water resource (the chalk aquifer) at exactly the time when water resources are coming under greater stress from a changing climate and when the cost of living is putting a squeeze on the nation’s finances: all to what Rob argues will be arguably of little ecological benefit. 

So, I instinctively want to disagree with him, but I find myself partly agreeing with him, even if we are coming from different points of view.

Rob gave a webinar presentation on this subject last week to the Geological Society’s groundwater forum.  The audience was – as you may have guessed – comprised almost entirely of hydrogeologists. There was much agreement with Rob’s argument and so the kickback will be well supported by experts, I suspect. You can watch the presentation HERE, but I’ve written a layman’s précis of the argument in blue below. 

Even though Rob apparently argues for something like the exact opposite of what we (ie. Chalk Streams First) have been arguing for (the restoration of flows to headwater chalk streams and the chalk-stream tributaries of systems like the Colne) I am very keen to find common ground, for the reasons expressed above: unless we get these abstraction reductions right – properly planned and judiciously delivered in the right places, at meaningful scales and allied with habitat and water quality improvements – we will undermine the case for them altogether and we’ll be back at square one. 

This is a very finely balanced argument: for the first time ever the regulators are planning a national re-plumbing that allies public supply resilience with environmental restoration. Fantastic! But it’s expensive work and we have to get best value from the investment. And we also have to make a powerful case for the continuing inclusion of environmental restoration in the definition of best value: it will fall out the door if we spend money unwisely.

In an effort to find that common ground I have made notes (in red) against Rob’s argument (in blue), pushing back here and there but agreeing where I think it is right to agree. Rob says “hydrogeologists unite”, but in the end we want hydrogeologists, environmental regulators and environmentalists, Ofwat accountants and our political leaders all to unite, for without common agreement on the problem and the best solutions we’ll be on an adversarial merry-go-round for ever.

I will post comments from anyone who wishes to join the debate over Christmas.

Précis of Rob Soley’s webinar presentation, organised by the groundwater modellers’ forum of the geological society:

Rob’s words in blue.

(discussion/comments by CRW in red)

Rob emphasised that he is “standing on his own soapbox” to air concerns about proposed potentially enormous groundwater abstraction reductions in the national framework draft plans. The elephant in the room, he says, is vaguely greenwashed and represents water resources folly in the pursuit of questionable ecological benefits.

‘Sustainable’, Rob argues, once encompassed ‘environment + people + carbon + money’. Now, river-flow standards are being pursued regardless of benefit or cost and we are on the verge of giving up a huge amount of groundwater storage. The altar of naturalness has made smart management a ‘dirty’ concept.

(Worth remembering that this pursuit of river-flow standards is only a potential pursuit at the moment: right now many chalk streams around London and Cambridge and into Kent are very heavily abstracted – abstraction totals of between 30% to 60% of recharge from rainfall – and will continue to be for years to come, no matter what. 

I agree that ‘smart management’ should not be sacrificed on the ‘altar of naturalness’)

In the early noughties the EA developed an abstraction-pressure screening process, consisting of a natural-flow duration curve, below which hung an impacted but idealised flow threshold (the Environmental Flow Indicator or EFI): in the places where the actual flows dipped below the idealised impacted flows a sustainability-assessment screening process was conducted which considered the environment + people + carbon + money. Over the past 20 years that definition of sustainable has changed, until now it considers only the environment, with the target an imperative. 

(This isn’t quite true. Rather, over time the weighting and even definition of these values has changed and therefore the balance within the definition of sustainable has changed. For example, what people are prepared to pay for has changed as their feelings about the importance of the natural world have changed: the definition still includes people, what they care about as well as the cost of water from their taps. The carbon cost may change too and certainly will when humankind cracks nuclear fusion, at which point the carbon costs of groundwater abstraction will become the absence of wetlands, and the definition of sustainable will once again have to shift to reflect this.)

And the target has been tightened.

The risk is that many of the reductions will not deliver the anticipated benefits. The process of national re-plumbing is going to be hugely expensive. With climate change our lows flows are likely to fall and so we need to consider how to make our environments more resilient.

Previously the map of groundwater (GW) abstraction impacts included the good (green), bad (amber) and ugly (red). The desire now is to turn the whole map green, by reducing the current national total groundwater abstraction total from 6,300 Ml/d to 3,500 Ml/d. We will attempt this by moving from a system of local water for local people and building more pump transfers, desalination plants, surface reservoirs: and all just to stand still (ie. reduce g’water abstraction) and before we address sustainability of water supplies.

(The environmental impact of “local water for local people” varies greatly depending on population density versus rainfall. For the chalk streams around London that ratio and the ‘local for local’ principle condemns the rivers to chronic and significant flow depletion. Local systems are gravity-dependent and thus subsidised by the environment while that environment gets bypassed in the supply-discharge loop. There is always a cost: it’s just a matter of the degree to which nature picks up the bill versus what we are prepared to pay in order to retain/restore nature.)

Switching off GW abstractions on this scale will sterilise our access to a vital resource while the environment will continue to be stressed by droughts and climate change. 

(Worth pointing out here that the Chalk Streams First concept is not proposing to “sterilise access to groundwater”: as a concept CSF still sees the aquifer as a water-resource reservoir. But CSF argues for using the stream as the means of delivery, rather than bypassing it: hence the name Chalk Streams First. Note that later in his talk Rob tries to show the difference between groundwater abstractions that subtract directly (both temporally and spatially) from the stream flows and those that subtract from distant storage with a delayed impact.)

We should carefully prioritise GW-abstraction reductions, alongside better management and habitat creation, yielding quicker, cheaper, and better ecological outcomes. .

(Conditionally agree: quicker, cheaper, better than ? … abstraction reductions per se, or poorly planned abstraction reductions? It shouldn’t be ‘either, or’.)

How did we get to these levels of proposed reductions?

The EA’s first national screening process was the CAMS ledger, incorporating 1200 assessment points of flows often at flow gauging station to improve confidence, and a screening process of natural versus recent actual and fully licensed flows.

The water framework directive (WFD) added 8,300 assessment points, with concomitant upstream migration of assessment. The assessment tool became the Water Resources GIS (WRGIS) linked to CAMS ledger spreadsheets. The screening process fed into WINEP.

WRGIS + the “FIXIT” tool fed into the national framework, looking at places where flows are below the indicator and calculating the reduction in abstraction needed to meet the target. It worked iteratively down the catchment, waterbody by waterbody. This developed the numbers the EA sent to water companies. Initial estimates of the groundwater abstraction  reductions required (to meet the ‘Business as Usual’ environmental flow standards without any water body exclusions and before accounting for climate change) indicated a total reduction of 2713 Ml/d from 6228 Ml/d (recent actual) (and a reduction of 4682 Ml/d from 11300 Ml/d fully licensed).

The chalk stream strategy has catalysed the further upstream migration of assessment: now quite seriously on the table is the need to protect chalk springs “where they are”. Protecting perennial springheads where the Q99 is close to zero: 5% of no flow is no abstraction. The conclusion of this is that “this is not an aquifer for people anymore”.

(The chalk strategy made the point that flows at the waterbody boundary aren’t necessarily representative of flows higher up the catchment, especially when the assessment point is below a significant discharge. There are plenty of examples, but the Ivel, for one, is assessed downstream of the Pix tributary and a sewer discharge: it is assessed as “supports good” for flow when the upper, chalk stream reach is very frequently dry. Concluding that arguments for the river’s restoration amount to “this is not an aquifer for people” arguably does not reflect how much people have come to care about their local chalk streams. In fact, the chalk strategy has proposed that we need strategic abstraction realignment in the places where abstraction is currently 20, 30, 40 or even 50+%* of recharge. This does not have to mean a 100% net loss to supply at all, but rather an evolution away from old-school infrastructure towards intelligent, conjunctive systems that allow the streams to flow whilst also utilising the water for public supply. This is perfectly possible, but it will cost some money.

*Interestingly, Rob agrees that A%R is perhaps a better way to assess abstraction impact and reduction prioritisation, because driving flow targets higher and higher up the catchment leads to increasingly stringent and unrealistic abstraction reductions: this is because chalk streams are naturally ephemeral in their upper reaches and trying to achieve no more than a 10% reduction from a tiny amount of flow or even no flow effectively amounts to zero abstraction: the meaning of his penultimate line in the preceding blue paragraph.)

Also the approach to the environmental flow regulation has tightened. We’ve gone from an assessment where sustainable included considering things more broadly to one where you just have to meet the flow standard. There is a mechanism of local override but it is usually impossible to make that stick because the data isn’t there and it is impossible to move away from the precautionary standard. 

(This is rather as if the precautionary principle has triumphed and we are in world of fully naturalised flows. It hasn’t and we aren’t.)

The national framework has tightened this yet further, so that now there is a notion that all chalk streams should be ASB3, all salmon streams should be ASB3. There hasn’t been a great deal of evidence presented to argue why that should be. There’s just the notion that these things are crown jewels, “without considering whether those standards are what the ecology really needs”.   (without clear impact evidence).

(Abstraction sensitivity bands (ASBs), as the chalk stream strategy shows, evolved out of flow targets which were originally determined by river type and expected macrophyte, invertebrate and fish communities (and their dependence on flow for health). ASBs , therefore, should be determined by a river’s type / potential, not current condition. But ASB designations have become muddled in places by a somewhat automated process that managed, for example, to designate streams like the upper River Nar as ASB1 (least sensitive). Every single chalk stream in England once contained salmon and nearly all still contain trout and often sea trout (the presence of salmonids, especially migratory salmonids should mean automatic ASB3 designation). Chalk streams’ natural macrophyte and invertebrate communities are also rheophilic (flow loving) and if the actual communities are now different (ie dominance of chironomid lava and cyprinids) this will ALWAYS be the result of anthropogenic modifications, usually a combination of abstraction, impoundments, canalisation and pollution. Therefore, there is a very good case for arguing that all chalk streams should be ASB3 because, the ecology of a chalk stream depends on flow. However, in the chalk strategy we have also conceded that ASB3 might not be appropriate (ie it would signal unjustifiably large abstraction reductions) in the lower reaches of big systems, which would benefit from upstream flow recovery anyway, or systems that are so heavily modified as to make restoration of ASB3 flows rather pointless, because the bigger constraints are immovable navigation locks or such-like.) 

All of that is true at the moment however bonkers the cost.

(The total reductions mooted at the moment do appear to have been generated by a computerised exercise (probably unavoidable as a first pass) without the important next step of prioritising and strategising. This next step is really important.)

And at this stage of the WRMP all the water companies are saying “okay, we’ll put it into the plans if that is what you want” and that’s going to go round the hoop until it gets to Ofwat, who may well tell us that we can’t afford it.

We need to get back to a more holistic, less siloed approach (flow + m’ment + habitat + water quality) to deliver real local biodiversity benefits more quickly and affordably “without trashing our resilient GW supplies on a massive scale” “with some understanding nationally of how much money we want to spend on this problem”. 

In parallel with this story there has been a development of regional groundwater and river-flow models: you can use these models to look locally at each stream cell and the river waterbody outflow points to check the compliance with these standards. 

There are lots of examples where both modelling and experience show ‘disappointing’ returns at low flows relative to the amount of abstraction reduction.

(For various complex reasons a unit of abstraction (or abstraction reduction) tends to have a greater impact on high flows than low: ie. if you reduce abstraction by a given unit (say 1 Ml/d) the impact on flows will be well over 100% at high flows and as little as 30% to 20% at low flows*.

*The impact on flows is expressed as an impact at the time, but this is not the full picture, because the impact is not a direct one but takes place via the impact on groundwater levels. A unit of water abstracted at low flow periods may have a smaller impact on the force which drives flow (because groundwater levels are low), but it nevertheless removes that unit from the total flow discharged from the valley: in fact it creates a debt to future flow, by delaying the rise of groundwater levels during recharge. This is why the oft repeated idea that abstraction has no impact on flows once groundwater levels have fallen below the river bed – and the river has dried – is misleading. It has an impact on future flows just like accumulated debt has an impact on future spending power.)

There is a good example on the south coast near Chichester of a chalk source on the River Wallington, between the River Meon and Bedhampton springs. Outflow points from the aquifer are at different elevations. The Wallington is relatively higher than either the Meon which gets baseflow most of the year round where it flows off the chalk and the Bedhampton springs at the base of the chalk. The impacts of the abstraction show that most of the impacts on the Wallington occur at high flows when GWLs are high and the chalk is spilling. On the Meon the impacts are constant through the year and at Bedhampton the impacts at low flows are actually higher than at high flows (when the aquifer overflow is pouring out of the Wallington). All because of the different elevations of the drainage points from the aquifer. The variable pattern of impact is true in other settings, for a combination of additional reasons to do with the non-linear behaviour of the aquifer, the variations of permeability with depth, winterbourne path-lengths changing as the aquifer fills or drains, the layering of the aquifer, evapotranspiration rates as groundwater comes close to the surface etc etc.

(The impact of abstraction is shared between three sources of discharge from the aquifer: the Wallington, the Meon and the Bedhampton springs: very simply you could see them as three vertical columns of holes with different uppermost elevations in the side of a bucket: the Wallington holes extend much higher up and as the water runs out of the bucket so the flow deserts these holes first, whereupon the impact of the abstraction becomes progressively more exerted upon the other two columns of holes. In this case, therefore, the impact of abstraction on the Meon and Bedhampton, but especially the latter is actually higher at low flows than high, because the impact is shared across three streams, one of which switches off almost completely.)

Therefore it is important to use these latest models to “wise-up” the EA tools such as the CAMS ledgers and the water resources GIS, because if not WINEP decisions are based on calculations that may not reflect reality.

Recently, and in response to the chalk strategy, the EA has proposed assessing flows at the perennial head of chalk streams, called Point X. The Fixit tool can be used to determine how much abstraction reduction would be needed to meet the flow targets at all the points of perennial outflow. 

Looking at the Cam Bedford Ouse model: to meet the WFD flow targets at all of the waterbody boundary assessment points abstraction would have to be reduced from the recent actual volume of 144 Ml/d down to 61 Ml/d. While to meet the same target at the springs (rather than the waterbody outfall) abstraction would have to come down to 18 Ml/d.

In the Quy sub-catchment currently 14 Ml/d of g’water abstraction leaves a non-compliance deficit of 7 Ml/d at the outfall. Plug in the reduction suggested for meeting the outflow compliance and there is still non-compliance in the headwaters. Plug in ASB3 numbers and this reduces, but not completely. Effectively you have to turn off abstraction to remove non-compliance at the spring-heads. This then creates a 5 Ml/d surplus (ref the target flows) at the outfall. 

(Worth noting that the generic CSF lumped parameter figures more or less match the sophisticated modelling figures in this case: reduce the abstraction to the point where flows re-naturalise and 12 out of 14 Ml/d manifest as surface flows at the outfall of the catchment. The Quy is on the Bedford Ouse system and is linked, therefore, to Grafham reservoir and in time to the proposed Fenland reservoir. In theory, therefore, we could restore flows to the Quy as in the CSF model, with a net average loss to supply of only 14%, albeit there would be additional costs involved in treatment and pumping and infrastructure. The proposal is not, therefore, to cease groundwater abstraction and source 100% of the reduction from completely different sources, but rather greatly reduce groundwater abstraction, find the 20% net loss through methods like efficiency improvements and then re-plumb in order to capture and use the recovered flow lower down the system. It is not accurate to represent the chalk strategy or CSF proposals as completely hands-off aquifers.)

Work by APEM for Severn Trent assessed the health of water bodies across Midlands against degrees of variance from natural flow. Pooled evidence suggests that at Q70 most sites with impacts of less than 50% are at good or better, (against EFI allowable reductions of 15% to 24%). This suggests we could adopt a less precautionary approach.

(I’m not convinced this case provides a useful application to chalk streams: were the assessed rivers in the Midlands salmonid streams with rheophilic ecologies? Rob’s main point though was that pooled hydro-ecological modelling should be carried out for chalk streams too, in order to see what the evidence suggests across the range.) 

The CSF model is a very simple lumped model. But “it fits really well”. Even with a simple non-linear representation of the head driving flow into a chalk stream, you get an indication of lower flow recovery at low flows compared to high flows. CSF is a good example of a modelling tool that is a lot cheaper and quicker to run but it doesn’t incorporate an understanding of the location of individual abstractions and how that influences their different impacts on river flows, which is why we can’t rely on it for making some of the really big decisions.

(Agreed: CSF is not designed as a decision-making tool at a micro-scale. It is partly designed to bridge the knowledge gap between hydrogeologists and the layman, in order to democratise the discussion. It is also designed to provide quick and simple assessments of abstraction impact. The fact that it fits really well again and again must also say something!)

An example of where the CSF model would not yield the requisite level of detail and where the impacts of abstraction reduction may not be justified:

Upper Itchen, “Source A”: on the syncline between the Wey and Candover, a long way from the perennial spring heads. Where and when does this abstraction impact flows in the Rivers Wey, Candover and Dever? A steady-state abstraction impacts these three rivers with a similar pattern of variance as the Wallington Source: the biggest impact is on the Wey, almost 7Ml/d at high flow, down to 1Ml/d at low flows. The Dever impact on the other hand is much more steady 1 to 0.5 Ml/d. Added all together the impacts are 18 Ml/d at high flows and 3 Ml/d at low. In other words, at low flows “you might not notice it that much”.

(This is where Rob is trying to draw a distinction between chalk groundwater sources which subtract directly /almost immediately from stream flows and those that subtract from distant storage with a delayed impact. This upper Itchen source, like the World’s End source impacting the Meon, Wallington and Havant springs uses groundwater storage with, as Rob argues, minimised environmental impact. 

The reason: “this is a source that develops drawdown in the summer: that’s a good thing. It’s not mining. It’s taking water from storage rather than directly from river flows.” The process here is the same as why good groundwater augmentation schemes work … they provide immediate summer low flow gain in discharging to the streams (providing it doesn’t leak back in) because the impact of the abstraction is not instant – it is offset to the next recharge season.

Candover augmentation scheme also scheduled for decommission: in the past it has supplied up to 22 Ml/d for abstraction in droughts. It can also supply on a more frequent basis enough water to keep flows close to natural in the Candover. So, the aim of having flows close to natural can be achieved without turning off all these abstractions. But there is a mantra now that we have to restore everything “to natural” and that we can only achieve that via switching abstractions off.

(I agree with Rob that the concept of a natural aquifer is potentially a distraction from finding workable and good conjunctive solutions. Combined with downstream surface-water abstraction off-takes, the upper-catchment groundwater storage here (ie. aquifer) surely has the potential to deliver almost naturalised flow volumes via the stream: I don’t think we should rule out ideas like this. Augmentation has a bad reputation but we should question why, if it gives us a way to retain water supply resilience and ensure close-to-natural flows. We should try to arrange some open discussions between Rob, the CaBA chalk stream group, Chalk Streams First, and Natural England / Environment Agency on this topic.)

The upstream abstraction reductions of 11 Ml/d Source A 3 Ml/d Source B 26 Ml/d augmentation add up to 40 Ml/d. Plus another 40 Ml/d from downstream = 80 Ml/d of resilient drought supplies lost only to be replaced by effluent recycling / desalination / distant reservoirs and pumping: this is untried, costly (hundreds of £millions) and carbon heavy. The “environmental benefits uncertain”. Protected areas need active management to protect them … let’s not leave them entirely at the mercy of climate change without groundwater augmentation.

(As above: there are ways to reduce abstraction impacts without creating a 100% net loss to supply.)

Another example of where the cost of abstraction reduction may not be justified:

Avon: most of the Avon is within CSMG flow targets, except for the final 1km, where the flow deficit is -70 Ml/d, almost the entire supply for Bournemouth. To replace this will increase low-flow abstraction from the Stour, a river with less resilient base flows, via stream support, relocation of 30 Ml/d wastewater recycling, plus aquifer storage and recovery schemes, all at a cost of £300 million.

There is little evidence of ecological impact on this reach. None in terms of invertebrates. In terms of fish migration there is no clear correlation between fish migrating up the Avon versus flow or temperature, although there is clearly a spate flow response (Rob showed a chart of 2020 salmon runs into the Avon). In addition 2020 saw far greater returns than any of the previous years since 2006 through which time abstraction pressures have been constant.

(Salmon return numbers and timing depend on so many factors and the overarching control is undoubtedly conditions at sea, especially sea temperature impacted by global warming (unnatural) and the North Atlantic multi-decadal oscillation (natural). Our job is to ensure the natal streams produce as many salmon as possible: so the real question is whether a 70 Ml/d reduction in flows is likely to inhibit salmon from entering the system or reduce the salmon-producing potential of that system? At average flows in a base-flow supported system like the Avon, maybe not. In drought conditions, maybe yes).

Q: is the legal requirement to reach the SAC target worth 300 million? 

(I feel Rob has a point here, especially because the Stour is also a salmon river. There may be cheaper or better ways to overcome the real risk to returning salmon trapped in the estuary in drought conditions: for example, salmon are attracted to velocity and turbulence (as well as the scent of fresh rainfall) when running upstream and there must be ways to create both in the lower 1km?).

Ref the future we know flows are on a downward trend with climate-change impacts. Where will supplies come from if we abandon g’water?

What do g’water modellers need to do?

• need to make their models fit. CSF fits even if g’water modellers don’t believe the concepts*. But regional models which include the concepts don’t always fit very well. Need local refinements for credibility.

*(maybe the concepts fit too!?)

• have to engage in the model wising-up processes to improve the national WRGIS data

• need to use the models to give stakeholders engagement: make model easy to share and improve

• need to talk about ecological benefits versus cost and challenge the green myths which say that:

• vast GWABS reductions are good (unwise, costly, uncertain benefits). 

(Agree, we need to be strategic and judicious to avoid the risk of undermining the whole project.)

• GW augmentation a bad thing (actually supports river flow and abstraction). 

(Agree, we need to consider the role of using the stream to deliver water: this is not augmentation as such, but a different way to plumb water supplies. Even pure augmentation has its place.)

• we’ll easily use less water (a very uncertain outcome).

• we’ll easily reduce leakage (without digging up cities?).

(Agree, both demand and leak reduction offer uncertain, untested savings at this stage. We need schemes that provide certain relief to the highly stressed chalk streams and we need them soon!)

• wetlands will improve drought flows (may just increase evapotranspiration).

(Yes, but they are still ecologically desirable and they lock up carbon.)

• protected areas need to be left as “natural” (no such thing. active management is a good thing).

(Agree, we need to actively manage.)

• make the most of our aquifers for people and the environment. Embrace well located groundwater abstraction reductions. Encourage effective GW river support schemes.


• work across organisations to deliver biodiversity benefits now.

(Wholly agree)

• reclaim a more holistic meaning of the word sustainable.

(Yes, but values change. Holistic must include those changes too.)

In summary, Rob is saying that we should be very wary about abandoning our climatically resilient (mostly chalk) groundwater supplies and investing many millions in an untried, untested, carbon-costly re-plumbing exercise, all in the name of uncertain ecological benefits. Instead, we should keep most of what we have in place, make reductions in a few locations where they will make a big difference to flows and ecology, and instead we should work on habitat improvements which will give us better outcomes for less money.

And I agree with some of that, certainly that we should carefully prioritise abstraction reductions so that they deliver tangible gains, something that will require transparency, knowledge-sharing and democratic discussion. But it is not a question of abandoning chalk aquifers so much as allowing chalk streams to become the means of delivery of water from the aquifer to the tap, meaning that restoring flows should amount to much smaller net reductions in public water-supply than the bare modelling headlines suggest. Habitat improvements can make a vast difference, but only once flows are back towards an acceptable level: in many chalk streams around London, Cambridgeshire and Kent where abstraction is over 20% and up to 50%+ of average recharge, flows are not acceptable. But all these deficits added together come to a manageable volume -400Ml/d) especially when it is possible to reclaim much of that water lower down the catchments.

The chalk strategy Implementation Plan: V1. 2022.

(Above: not so long ago this part of the River Glaven was locked in a tunnel: now look at it! There’s hope for all our chalk streams if we dare to make it happen)

I should have posted this on Friday but I was busy chairing the Chalk Headwaters Conference at Sparsholt and catching up with many old friends from Wessex chalk stream country. My presentation there was on the chalk strategy but also the chalk strategy implementation plan, which was published that day. Please take a look at the new plan HERE.

This plan has been many hours, weeks, months in the making; many phone calls, emails, meetings, consultations and negotiations. It’s not a once-and-for-all fix-all, but I do think it marks a step-change in our collective attempts to restore good ecology to our beleaguered chalk streams.

Not only do we have a consensus plan with consensus actions and timelines, but we have now garnered explicit support from all quarters – regulators, industry and NGOs, and the small-but-becoming-bigger-every-day army of chalk stream enthusiasts – for ideas like the flagship projects, the review of waterbody boundaries & abstraction sensitivity bands, the enhanced scenario for chalk streams in the national framework planning process, Chalk Streams First etc.

It’s great too, to have such supportive statements from the Minister, the Rt. Hon. Rebecca Pow MP, and from Defra and the Environment Agency. And from Ofwat too. These give us real gas in the tank when making the case for all the things we need to do to bring chalk streams back to health, whether that’s abstraction reduction or sewerage infrastructure investment or physical restoration of habitat.

Sadly, we are still not quite there when it comes to the greater and more explicit protected status we all asked for, along with the necessary investment driver. But I still have hope: the changes in government over the summer stalled progress, and it would be nice to think things might get back on track now Minister Pow is in post again. We all know what a difference enhanced status would make, by taking the brakes off investment along the lines established by making chalk stream high priority sites in the stormwater reduction plan.

This implementation plan will be revisited and revised every year, a commitment that I hope will help hold us all to task. So, over the next 12 months, let’s see how far we can get with actually making some of these ideas a reality. I hope, in 12 months time, to see tangible progress with the planning and construction of integrated wetlands, with the agreed level of environmental ambition for chalk streams in the national framework, with Chalk Streams First not only in the Chilterns but elsewhere, with the flagship projects and with the strategic and outcome driven planning of stormwater discharge reduction.


My five minutes in Westminster: the WRSE parliamentary launch

I was very pleased (with thanks to Trevor Bishop, WRSE director) to be given five minutes this morning to talk about Chalk Streams First as part of the parliamentary launch of the WRSE draft regional plan.

Trevor opened the speaking with an encouraging summary of how this plan could be a real game changer in terms of making environment stewardship integral to a more resilient and sustainable water resource infrastructure. As I say below, this is our best chance ever, to build a better system that is fairer to the natural world. And to restore our over-abstracted chalk streams!

It was great to see Sir Charles Walker MP, The Rt Hon Phillip Dunne and Sir Oliver Heald, MP – all stalwart chalk stream supporters over many years. Many thanks to Sir Geoffrey Clifton-Brown MP for hosting, on behalf of WRSE.

You can read the plan and give feedback HERE. Please do take the time to take a look and especially to give feedback ref the importance of abstraction reduction for chalk streams.

There will be a webinar on the 22nd Nov at 1330 to 1500. Register to attend HERE

My five minutes worth were as follows:

“As we plan for the future it’s important to remember the past: the miracle of running water and flushing loos in every home, on the one hand, and on the other the true cost that miracle imposed on the natural world.

In a cupboard in the High Wycombe public library there is a Sanitary Inspector’s report from the mid-19th C on the conditions in which the chair-factory workers of the town were living. Their water came from the stream, over which hung latrines, or from wells in the floodplain, the wells sometimes only a few yards from garden-shed loos, also holes in the ground, shared by forty or fifty people. 

Most people were ill more or less all the time: they called it low fever, and thought it came from the awful smell, but it was cholera and it came from the dirty water. The report recommended piped water and a sewage system, but the councillors were concerned about the cost and it took decades to materialise. In fact, the slums themselves lasted until the 1950s when they were finally cleared and the occupants rehoused in airy, council houses on the hills above the town. 

In those post-war years the resource of abundant, clean water in the chalk hills under those lofty new houses was nothing short of a miracle. It enabled the re-housing of Londoners bombed out by the Blitz into smart new towns and garden-cities in the Home Counties.

It enabled – and it subsidised – an amazing growth in prosperity and health. Hardly surprising that groundwater abstraction from the chalk aquifer grew almost exponentially in those post-War decades, climbing to a peak in the mid-1980s where in many of the chalk valleys around London over half the rain that fell from the sky to fill the aquifers was taken for public water supply. In dry years an average of half the rain, became all of the rain. 

And although the water was free to us, there was a bill: the natural world picked it up. Those lovely chalk streams – a freshwater marvel almost unique to southern and eastern England – ran dry.

For forty years we have wrestled with how to resolve this dilemma: the convenience and low cost of water from the chalk aquifers and versus the ecological impact of drying and dry chalk streams. Round and round we go, sometimes denying the problem, endlessly measuring the problem, but never quite fixing the problem.

Now, through this regional planning process we have the best chance we’ve ever had, and may ever have, of achieving a better balance between the needs of society and those of the natural world.

The potential component of the plan that I’m especially passionate about consists of realigning the way we take water by creating the sort of system we should have built in the first place, if only we’d known.

Instead of taking water from the ground in the headwaters of these lovely chalk streams, we should take it much further downstream, after it has flowed down the rivers and nature has had first use: hence the name of our proposal, Chalk Streams First.

Chalk Streams First is supported by all the major environmental charities – the Rivers Trust, Wild Trout Trust, Angling Trust, the Wildlife Trusts, Wild Fish and WWF – as well as the local environmental groups in the Chilterns and Hertfordshire chalk hills, where the opportunity is ripe for the taking.

Chalk Streams First is a proposal that greatly reduces abstraction pressure without losing the water to public supply: much of the water left in the ground becomes surface flow which can be taken further down the river, placed into storage reservoirs and then used to supply all the places formerly supplied by the groundwater abstraction. 

There are potential variations on the theme too: inter-regional water transfers like the Grand Union Canal, or Severn to Thames, could bring water into the upstream catchments, with the recovered flow going on to London. 

Groundwater abstraction in the headwaters can be replaced by groundwater abstraction further downstream where there would be less ecological impact. 

In places where there is no reservoir, or to get us through 18-month droughts like the one we have just experienced, we could use emergency groundwater schemes and use the chalk streams to deliver the abstracted water to public supply off-takes.

The point is, we can do it: we can have flowing chalk streams and resilient public water supplies.  It just requires political will and engineering ingenuity. And while it needn’t cost the Earth, it might just save our piece of it. Please support Chalk Streams First and help us to make it happen … soon.

Thank you.”

Sir Charles Walker, Trevor Bishop and yours truly at the parliamentary launch of WRSE’s draft regional plan.