The Destruction of our Chalk Streams Continues – But they could be Saved.

Beverley Brook at Wimbledon Common

Following my blog post last week about the ecocide of many of England’s chalk streams, I received some queries which I have decided to answer in the form of another post. As requested, this includes more links to further sources of information.

winter afternoon on River Chess

Can Chalk Streams really be compared to the Rain Forests?

I’ve been questioned over equating the plight of chalk streams in England with the destruction of the rain forests.  In terms of the percentage being damaged and destroyed, the chalk streams are far less likely to survive.  There is also an ethical context as voiced by Charles (now Sir Charles) Walker, Member of Parliament for Broxbourne, in an adjournment debate in the House of Commons

“It is important that I put the situation in context. As I said a moment ago, we have 85% of the world’s chalk streams and most of them are highly degraded. I find it extraordinary, given our own poor environmental record, that colleagues in this House lecture Indonesia and Brazil so freely on their responsibility to the rain forests. Of course, those two countries have a huge responsibility to the rain forests, but if we cannot save the chalk streams that are literally in our own backyard, what are we doing lecturing other countries on their environmental responsibilities? Saving the world does not start with the rest of the world. Saving the world starts right here, right now, doing our bit locally with our chalk streams—think locally, act globally.” Hansard Vol.663 col 1168 22 July 2019. 

Dry bed of River Misbourne

There are only 200 or so chalk streams in the world, with about 85% of them in England.  About a dozen of these have had major sections dry out completely whilst many others are so depleted that normal aquatic life cannot be supported. Although it was brought out two years ago, this report from the WWF provides a well-researched easy to read overview.

Water for wildlife

The following WWF reports are slightly dated but a good introduction to the subject of chalk streams and related issues. The reference section of each are good starting points for further study.

The State of England Chalk StreamsRivers on the EdgeRiverside Tales

Is it true that Loss of Chalk Streams can result in Extinctions?

I wrote in the last post:

Removing and “saving” a few headline aquatic species, whilst of value, does not address the full degree of devastation the drying-up of a chalk stream brings.  To describe it as ecocide does not seem extreme. It is a loss of a complete ecosystem from mammals such as water voles, through the invertebrates that support so much of river life, to the single cell organisms and bacteria that contribute to water quality.  Some of these will be adapted, perhaps uniquely, to the stream, or even the pool in which they are found.

I should have added, that in the ‘lesser’ species, unique populations have, in all probability, been lost.

The last puddle in the Misbourne

It would be ridiculous to suggest that it did not matter if African elephants were wiped out as there were always Asian elephants – yet this appears to be the approach being taken by the UK Environment Agency and water companies.  The random catching and distribution of fish from a chalk stream hit by over abstraction is equally as damaging.  These fish should be relocated within the same river system or kept in a contained environment for later release once the river has recovered.

Trout in River Itchen at Tichborne

A paper published last year in the ‘Journal of Fish Biology’  detailed recent research that has shown that the salmon found in our chalk streams are genetically distinct from those in other UK rivers. It costs money to read on-line but, for those with the interest, the PhD thesis of one of the papers authors is available here: “Population Level Variation of Atlantic Salmon in the Chalk Streams of Southern England and Neighbouring Regions”.

It has been recognised since the 19th Century that there are about 20 distinct populations of brown trout in this country.  If a full study of the DNA of the UK trout stock is completed, is considered likely that genetic populations unique to chalk or hardwater streams will be identified.  In recent times most concern about this has been around the affect that the escape of fertile trout, from fish farms and not naturally native to its location, would have. The report, “Genetic impacts of stocking on indigenous brown trout populations” by the Environment Agency, examines this.    

Fishing hut on River Itchen

How can the Chalk Streams be Restored to full Biodiversity?

The principle that those responsible for damaging the environment should pay for its restoration is long established. Sadly, the water companies all too often seem to evade this.  When a stream dries out repeatedly, an entire ecosystem is lost – it cannot restock itself when the water returns. 

Dry bed of River Chess July 2019

If a fish migrates up stream following the return of water, it finds no aquatic plants to provide shelter or food, or to vary the water flow. The bacteria in the stream bed that would have helped condition the stream will have gone. Whilst the stream was dry, any rain storms will have caused run-off to enter the dry watercourse. With no water flow to dilute and flush them away, the pollutants will have soaked in to the upper layers of the stream bed contaminating it.  Local insect populations dependent on the stream will have crashed – there will none flying above the water, and no lavae in it. There will be no young fish or fish of the smaller species. No invertebrates, no anything. That returning fish has nowhere to live, nowhere to breed, nothing to eat nor any heathy water to live in. The same applies to insects, amphibians and small mammals.


The bird that rely on insects for nourishment will be affected. Those that rely on these streams as a source of insects, to fatten up before migrating, will have had thin pickings this autumn.  With no larvae, in the spring the insects will not be present in sufficient quantity for some birds to reach breeding condition or to support a brood. I guess some spiders will be hit by this as well. Riding my bicycle around the chalk streams of Hertfordshire last summer it was noticeable how rarely I swallowed a fly. I reflected at the time. ‘… at least I’m not a poor old bat’.

Great Crested Grebe.jpg

So, if the water companies are to make good, as far as possible, the damage caused by over extraction and failure to seek a drought order; what should they do?

I argue that each water company should be ordered to build a series of fluvaria, each several hundred metres long. One for each section of dried up chalk river or stream in that company’s operational area, and each supplied with water from the source of that stream’s flow.  Samples of the closest surviving stream beds to the dried-up sections should be taken and used to seed new beds created in each fluvarium.

Healthy bed of River Wandle

The process for stocking with plants, fish and other creatures to start building a new ecosystem would be slightly different. Where relocated stock can clearly be identified, they can be moved to the fluvaria. Before catching and stocking from elsewhere in the same river, or river system, a trawl for data on the mix of species associated with the dried-up section will identify what that mix should be.  Fortunately, naturalists have studied these streams and kept notes over the centuries. Collectively, the angling community has a wealth of historic photos showing not only their catches, but also the wider river environment. With the right level of resource, a profile could be drawn up of what that river in good health should look like. In some species it may be possible to find features that identify from which population the pictured specimen came. As each fluvaria is stocked, all organisms going into it should be DNA tested to identify individual populations and traits within them.

Trout fishing Beddington Park

The fluvaria would then provide the base material to breed up and multiply stock to return to the associated river system. This requires each fluvaria, once established, to have an associated plant, fish, amphibian and insect etc nurseries.

Projects like this would need to last for at least a decade and would cost the water companies many millions of pounds – indeed I could see Affinity having to spend well over £50 million; much of it front loaded. This is not a bad thing as it would be a delayed spend of the money saved through not investing to meet their statutory duty in regards to maintaining a resilient and sustainable water supply. Just as those who damage the environment should pay to make good; they should also not be permitted to profit from it. When it is cheaper to pay fines rather than act responsibly, large corporations have tended to lower their standards.

Fishermans logbook

The study of historic data to establish a new standard for these water courses; may result in a higher baseline standard of water flow and maintenance than has been seen in recent times.  If it was shown that traditionally a trout fishery produced catches of fish averaging 2.5 lb each, with the occasional trophy fish of 4lb; then the amount of water in a stream and other environmental conditions to achieve this can be calculated. The DNA sampling would greatly increase the scientific knowledge and assist future conservation. The water companies would no doubt complain that for them to have funded this is unfair but, it is however, necessary for proper restoration and can count as restitution.

Consumers water bills need not be affected as this money has been saved once already and is only a fraction of what the cost will be if proper investment in future supply does not take place.

Surely some Chalk Streams have always Dried Out

Looking Across the Chilterns

Chalk streams typically start with a spring that rises from the slopes of hills that are formed predominantly of chalk.  Rain that falls on these hills percolates into the chalk where it is held and forms an aquifer that then supplies the chalk streams. These are typically wide and shallow and, due to the filtering effect of the chalk, their waters are alkaline and very clear.

Confluence River Colne and River Ver

The relationship between a chalk stream and the underground aquifer is such, that the health or state of one, reflects that of the other. Both rely on being recharged, predominantly from rainfall, and are susceptible to drought or over exploitation.

An aquifer filled with water will flow from springs, winterbournes (streams, or ‘bournes’, that only flow in winter), and into the chalk streams. As a year progresses into spring and summer, the groundwater level in the aquifer will lower and the winterbournes and most of the springs will dry up, leaving just the chalk streams with water in them.

I’ve produced the graphic below (based on one by the WWF) to illustrate this.

Aquifer diagram

The pictures below are of the South Dorset Winterborne which feeds into the Frome. The first shows it in winter with water flowing through it. The second is after it has dried up as the water level in the aquifer has dropped. 

South Winterborne in flowSouth Winterborne Dry

Historically these would disappear and reappear about the same time each year – perhaps flowing for a little longer after a wet winter, or a little late returning following a dry summer.  What this shows is that even with seasonal variation it would have been extremely rare for the aquifer not to have been fully recharged each winter. 

There are now winterbournes that do not reappear some winters, if at all – they have simply disappeared. Earlier in the year the one below, after three completely dry winters, was looking more like pasture than a bourne. This is due to the aquifers not having a chance to recover from excessive abstraction.

Ghost of a winterbourne

The current crisis is that it is not just the winterbournes, but major chalk streams that have dried up.  In my previous blog post I stated that this was due to over-abstraction of water, as illustrated in the third of the diagrams above, rather than the current drought in the South of England. 

The National Trust have a really good illustration and explanation on their website – just click on the  picture below.

Hughenden Stream in Hughenden Park

Whilst the drought has no doubt had an effect, the historic data on the state of the aquifers, water flows in streams and rainfall are all publicly available and allow long term trends to be monitored.

Brant Broughton Gauging Station

The River Levels UK website gives a snapshot of the current status of UK rivers on its homepage.

Riverlevels website home

Clicking on the ‘River Levels Map’ button brings up a map of river level monitoring stations.   Clicking on a particular monitoring station, shows current flow information for that river and, if you scroll past the advertisements on the page, trends over the previous week and year.  One needs to be aware that this only records the flow at that one point in the river’s length. So, for example, if the measuring station is below the waste water outlet from a sewage works, it will show that there is water flowing in the river; even if much of it above the outfall is totally dry. A number of chalk streams are dependent on this source of water.

UK River Levels

River Rib

National River Flow Archive

If you are interested in historic water levels in a river, these are available at the National River Flow Archive website, which also has rainfall figures.   The examples below show flows on the Chess at Rickmansworth for 2006, a year when parts of it dried up, and a wet year, 2014. Clicking the graphs will take you to the website.  A poke about will find the available data for any UK river.

Water Flows on River Chess

The site also publishes a monthly Hydrological Summary which besides rainfall and river flow, reports on groundwater levels and reservoir stocks.

Borehole at Oakhanger

Water abstraction data is less easy to find. An annual summary is available here   whilst further can downloaded from the Gov.UK website.

Gov logo

The risk is that over exploitation of a chalk aquifer will lead to the collapse of both geological and biological integrity.  Currently they are not recharging, or only partially so. In the House of Commons debate mentioned above, Charles Walker revealed:

“Affinity… reduced pumping at one pumping station on the River Beane by 90%, which was actually a very brave thing to do. Yet that part of the river has not started flowing again because the long-term damage to aquifers that have been used and abused for the past 30, 40 or 50 years is so extreme that it may take decades to recover.”

Totally dry River Beane

During the recent BBC TV series ‘The Americas with Simon Reeve’; he visited an area of California where underground aquifers have been totally exhausted and destroyed from supplying water for intensive agriculture and a rapidly growing population. As a result, the ground level has dropped by between three and ten metres. If the chalk structure within our aquifers was to dry, crumble and collapse; the resulting denser material will be severely restricted in its ability to hold water, with much running off rather than soaking in. 

Some water companies are protecting aquifers by artificially recharging them through pumping water from elsewhere into the boreholes. This is not without problem, and that which concerns me most is the bio-integrity of the aquifer itself.  The shallow layers of soil and plant growth above the chalk are an informal filter bed that rainfall passes through. If waste water from a sewage works is fed into a borehole; who knows what effect hormones, antibiotics etc. will have on any bacteria within the aquifer?  For some years now, Thames Water’s ‘North London Artificial Recharge Scheme’ has been doing this with the chalk aquifer beneath Enfield, Haringey and the Lee Valley. It is topped up with treated water to use as a back-up resource to boost supplies during droughts.

Sutton Bingham

Surely, it is more important that we have Water to Drink?

And this is why I say the water companies have failed in their duty to provide a resilient and sustainable water supply. To maximise profits, they will give assurance that they can supply water for any proposed development without making the necessary investment in supply infrastructure.

Over the last three years the situation could have been mitigated in part if the water companies had sought drought orders so that drinking water was not used to wash cars or water plants. This would, however, have highlighted the water companies, and the regulators’, failures in this area.

To be fair, some water companies are putting in infrastructure for large scale water transfers. Examples include Severn Trent’s Birmingham Resilience scheme; and Wessex Water building 24 new pumping stations and installing 200km of pipeline to create a supply grid.  Whilst these are great for regional supply, they don’t address the core issue that the wettest parts of this country are the least populated, whilst the driest have the densest population.

What we do not have in this country is any kind of National Grid for water and, given the problems of pushing water through pipes one is probably not that feasible. Water movement between areas though, still needs to addressed.

Hogsmill Sewage Works

Earlier this year I visited the Hogsmill Sewage Treatment Works. This was a really interesting afternoon and Thames Water even provided some rather nice (free) fish and chips. I had invited my partner to join me, but she wasn’t very impressed at the idea that fish and chips in the sewage works may merit being described as a ‘date’.

new water sources

One presentation focussed on finding new sources of water for the South East.  These included moving water from North to South of the UK using the canal network, and restoring the Thames and Severn Canal as part of a plan to move water from the River Severn to the River Thames.

Grand Union Canal near Watford..jpg

It seemed to come as a surprise to the water company representative when I pointed out that neither of these were new proposals. In the late 1990s, the civil engineering consultants W S Atkins proposed a scheme to transfer water using the Grand Union Canal – indeed I attended an exhibition about this proposal.  Some of the spillways, or bywashes, may have needed upgrading but most of the infrastructure is in place. Yes, some pumps would be required, but this is a relatively quick, easy and lower cost solution. The reason that canals and rivers tend to be favoured for large scale water transfer, is because it takes a lot of energy to push water through a pipe and, during that process, water tends to degrade.  A side benefit is that it puts more water into canals at times when the level is low.

Lack of water in Regents Canal

In 2001 I spent a long, but very pleasant day, walking much of the route of the Thames and Severn Canal as there was a lot of interest in restoring it.  The Cotswold Canals Trust has started the process but, as a voluntary  organisation funding a lot of the work through National Lottery grants, progress is naturally slow.  Given the relatively short distance I suspect Thames Water may still prefer to run a pipe, but restoring the canal offers numerous other benefits in the areas of biodiversity and outdoor activity.

Jubilee Bridge Thames and Severn Canal.

If these schemes had been taken on board 20 plus years ago when last proposed, they would now be operational and bringing more water into the South East.  With timely, planned investment, water companies can provide sufficient water in all parts of the country without destroying the environment. It is also up to consumers to use water more responsibly, and for waste water to be reused more effectively.

Stream in Summer.jpg

And finally

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Hogsmill River.jpg



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