Blog & News

Dramatic increase in Sewage spills into River Cam

The recently released data on sewage overflows shows a shocking increase in discharges from Cambridge City and Haslingfield Sewage Works.

During 2023, the aging and overloaded sewage works at Haslingfield, 5km upstream from Cambridge was spilling sewage for 3000 hours, in other words for 34% of the year.  Cambridge Sewage Works, just downstream of the city, was spilling sewage into the river where our boat race crews train, for 17% of the year.

As the graph below shows, both were dramatic increases from previous years.

We have asked Anglian Water what is going on, but not yet received a reply.

Their website says

Our EDM monitors and investments are helping reduce spills and have moved the dial in the right direction. Spills would have been considerably higher without it. However, it is important to acknowledge the exceptionally wet weather we had in 2023, particularly late in the period, which meant that 70% of our spills were in Q4 alone and in stark comparison to the extremely dry year in 2021, as climate change continues to result in more extreme weather events.”

It is true that late 2023 was wet, but to assess how exceptional this is, we have looked at the Met Office weather data for Cambridge, which has been monitored at NIAB (the National Institute for Agricultural Botany) every year since 1959.

The rainfall data shows that in 2023 Cambridge was a little wetter than the previous few years, but there only seems to be a vague relationship between the annual rainfall and the duration of sewage overflows during the year. 

The slightly higher rainfall in 2023 in comparison to 2020 doesn’t seem sufficient to explain the dramatic increase in sewage spills. So what’s going on?

The Met Office rainfall data for Cambridge, shows that March and October 2023 were both very wet, which might have been expected to create problems. But these 2 wet months can’t excuse Haslingfield Sewage works spilling sewage for 34% of the year.

Water companies are allowed to spill sewage into the river when conditions are “exceptionally” wet, but the definition of “exceptional” is unclear.

Looking back over the last 65 years, months as wet as the wettest months in 2023 have happened at intervals, but were they “exceptional” enough to make it legally permitted for Anglian Water to spill sewage into the River Cam?  We’ll leave that question for the lawyers to answer. 

However, as the longterm graphs show, Climate Change is making weather that was once “exceptional” seem “normal” so our water companies need to be urgently upgrading the infrastructure to cope.   This applies both to our sewage infrastructure, which in Cambridge is the responsibility of Anglian Water, and fresh water supply, which is the responsibility of Cambridge Water.

Cambridge’s wettest months seem to be becoming more frequent and wetter, and the rate of increase might itself be increasing. (In the graphs above and below, the longterm trendlines are shown by red dashes)

Winter rain doesn’t eliminate the risk of the summer pain from drought.

The same NIAB dataset shows that the average monthly temperature in Cambridge rose by about 3C since the 1990s.  Winter temperatures have increased even more dramatically: they are now around 6C higher than during the freezing cold winters of the 1980s.   This is probably mainly due to climate change, but increasing urbanisation may be contributing slightly.

These changes increase the risk of drought and of plant pests surviving the winter, while significantly changing our natural habitats and the species that can live here.

They also increase people’s desire to swim in the river, which is another reason why we want our water companies to make the necessary investments so that sewage spills become truly “exceptional” events.

Underlying everything is the growing threat from climate change, so we all need to take urgent action to reduce our contribution to the problem by cutting our carbon emissions. Unless we do, no amount of investment will be able to prevent the horrific consequences.

10 top tips for saving water

To help save our chalk streams:

  1. Go to www.cambridge-water.co.uk/saving-water and join GetWaterFit, the interactive on-line tool that provides advice and from which you can order free water-saving products.  If your water supply is not metered, apply to have a free smart meter installed.  This gives an incentive to save water and is likely to save you about £150 pa on water charges.
  2. Don’t flush every time you pee- ‘If it’s yellow let it mellow, if it’s brown flush it down!’  Reduce the quantity of water used by WC cisterns.  If you have dual flush, use the lesser flush whenever appropriate.  If not, put a hippo in your cistern:  https://www.hippo-the-watersaver.co.uk/.
  3. Fit aerators to taps. These add tiny soft bubbles that reduce the flow of water by about half while maintaining the water pressure, they can be fitted to most taps and are inexpensive.  The water feels nicer and soaks better. https://www.bestproductsreviews.co.uk/tap-aerators .  Taps that provide boiling water will also save water because they can give water of any desired temperature instantly.  These are available from www.quooker.co.uk.
  4. Have brief showers instead of baths.  https://www.bestproductsreviews.co.uk/water-saving-shower-head has an excellent choice of shower heads that use much less water and by aerating the water to give a better soaking shower.
  5. Only turn on taps as far as needed for the task, the full flow is often unnecessary.  Don’t run the tap when brushing teeth. Use a bowl when washing veg or washing-up by hand.  Then, instead of pouring the water down the drain, water plants with it
  6. Washing machines can use more than 100 litres on some programmes and dishwashers more than 20 litres. When buying new appliances select water efficient ones and use Eco programmes.  Wait until appliances are nearly full before setting them to go.
  7. Install water butts with drain downpipe connectors and water plants with rainwater. If necessary during dry spells refill water butts with water recycled, for example from baths or showers
  8. Take prompt action to have any leaky appliances in the house, such as dripping taps or cisterns, repaired or replaced.  Report any leaking water mains to the Cambridge Water Company on 01223 706050.
  9. Engage in consultations with organisations such as schools and businesses and encourage them to monitor and reduce their water consumption.
  10. Assuming a hosepipe ban is not in place, please use your hosepipes sparingly.  Aim the hose at the base of plants most in need of water, and water them in early morning or evenings when water will soak into the ground rather than evaporating into the air.

FAQs about Bathing Water Designation at Sheep’s Green

How does designation help clean up the river?

Designation is a powerful tool to accelerate the cleanup of the river. Firstly, because it shines an official spotlight on the water quality. Secondly, because the water quality here will almost certainly be rated as “poor” it imposes Statutory Obligations on industry to reduce the pollution from sewage works, urban sewage overflows and agricultural slurry.  Unlike general non-statutory calls to reduce pollution, the water industry responds to these Statutory Obligations, so this prioritises and drives real change.   Some of the key pieces of legislation are the ‘Bathing Water Regulations 2013’ , WINEP, which governs the water industry funding and WISER (Water Industry Strategic Environmental Requirements) As explained here, following designation, Ofwat are likely to require the work to be completed by 2027. Without the statutory “Driver” of Bathing Water Designation, Anglian Water could take as long as they liked, so the improvements would be likely to take much longer…. maybe decades.

Designation helps accelerate the cleanup, but we’ll need to keep up the pressure for wider change too. Ultimately, we need to change our relationship with the natural world, so water can be good quality everywhere. However, this will probably take decades and the whole farming and water management system will need to change.

I’ve heard that areas with Designated Bathing Water status MUST promote bathing in the area, which will increase the number of visitor. Is this true

No. This is completely false

The rumour probably results from the line in the Bathing Water Regulations 2013

3.—(1) Part 1 of Schedule 2 lists the surface waters that have been identified in England, other than excluded pools and waters, at which the Secretary of State expects a large number of people to bathe, having regard in particular to past trends and any infrastructure or facilities provided, or other measures taken, to promote bathing at those waters.”

We are informed that this means that it is a site that existing bathers use, with no signage prohibiting swimming, and where there are pre-existing facilities or infrastructure, such as steps, that support bathing.

We’ve also had confirmation from Clean River Ilkley that designation is not about marketing, and does not increase the number of visitors

Will designation increase the numbers of people coming to Sheep’s Green and the nearby Paradise Local Nature Reserve? 

In the short term, no. We are counting “bathers” this summer, and we qualify for designation. (Defra require an average of over 100/ day on the 2 busiest days, and we counted 237 on 10 August and 184 on 19 August and 478 on 10 September)

We know the water quality on the Cam is very likely to be rated as “poor” which will require the council to put up a sign saying “Bathing is not advised”. This will deter rather than encourage swimmers. The experience of other river groups, such as at Ilkley in Yorkshire, is that designation has made no difference to numbers.

However, 3-5 years time, hopefully the water quality downstream from Haslingfield Sewage Works will have improved (something we’ve all been campaigning for).  More people are then likely to feel safe enough to swim in the Cam at Byron’s Pool, Grantchester Meadows and Sheep’s Green.  

We welcome more people connecting with nature, particularly in our highly unequal city.

When considering the Sheep’s Green area, it’s important to remember that the vast majority of the people that come to the area, do so to access the Lammas Land paddling pool, playground, cafe and local walks. When we counted visitors to Lammas Land and Sheeps Green on 19 August 3:40pm-3:55pm, only 2% were swimming in the river. This means that even if the number of wild swimmers at Sheep’s Green does ultimately increase, it will make very little difference to the overall numbers in the area.

Why choose Sheep’s Green, when most people swim at Grantchester Meadows?

Defra only allow applications from inland sites if there are toilets within 500m, and if it’s a short stretch of less than 500m.  This ruled out applying for Grantchester Meadows.  Nevertheless, designation will benefit the whole river between Haslingfield and Cambridge, and people will remain free to swim anywhere.

I’ve heard the council wants it to become a “Destination”. Won’t this increase numbers?

This rumour is based on a misunderstanding. It may have come from the section of the city council motion on 20 July that ‘affirms the goal …of having the water management plan for our chalk streams based on being an ‘environmental destination’ with subsequent protection as sites of Special Scientific Interest (SSSI)”. 

Note that in water resource management government jargon, an “environmental destination” means a “long term goal”, not a “destination” in the tourism sense of the word.  The council motion is about getting a higher level of protection for the chalk streams from abstraction, which is something we very much welcome.

Cllr Katie Thornburrow has confirmed that the City Council has NO plans to turn Sheep’s Green into a vistor destination, and none have been discussed

I’ve heard the council will have to build showers and changing rooms and dredge the river. Is this true?

No. Bathing Water Designation is for the benefit of current “bathers”.  Theres no requirement to improve facilities, or to carry out any other changes.

Cllr Katie Thornburrow has confirmed that the designation does not require new facilities to be built and the council has no plans to do so

I’ve heard people calling it a Designated Bathing Area or DBA, saying that this means it’s obvious its intended to attract people to a small designated area. Is this correct?

No. The correct name, used by Government is “Designated Bathing Water.” This is because bathing is NOT restricted to a small area. In a river, water flows though the site, so a large stretch of river benefits from clean-up as a result of designation .

Are you independent?

Cam Valley Forum is a voluntary group, established in 2001, registered with HMRC as charitable. We are entirely independent, and politically neutral. 

As our website states, “We work with our extensive network of partners to protect and improve the environment of the River Cam and its tributaries”  We frequently criticise the water companies and others for pollution and over-abstraction.

In 2021, when our volunteers started monitoring the Cam for faecal bacteria (ie bacteria from poo), we received a small grant of £1,500 from Anglian Water as a contribution towards the costs of laboratory analysis. In September 2022, Anglian Water took over the test program, and they are providing us with test results until September 2023.  We are publishing these on our website here

We think the public deserve to have more reliable, independent information on water quality, than that provided by volunteer citizen scientists like us, or by the Water Company itself. This is why we welcome the help of a very experienced and professional body like the Environment Agency, who have responsibility for monitoring Designated Bathing Water sites.

Will it be 100% safe? 

Bathing Water Designation will reduce the chance of diarrhoea and vomiting from ingesting faecal bacteria. 

Most people who swim in the Cam do so without problems, however wild swimming is never 100% safe, so you should make your own judgement (and keep your mouth shut while swimming).  For certainty about safety, we advise swimming in swimming pools like Kelsey Kerridge, Abbey and Jesus Green Lido where the water is filtered and chlorinated, and the pool is supervised by lifeguards.

If the site becomes a Designated Bathing Water site, the City Council will have to display the Environment Agency’s annual water quality rating, in order to help inform the public of the level of risk. In addition to this, we are also encouraging the Council to display some Wild Swimming safety advice, as Oxford City Council has done at their Designated Bathing Site.

AGM and Annual lecture: Monday 18 March 2024 7pm-9:30

David Attenborough Building (Seminar Room), New Museums Site, Downing Street. CB2 3QZ

  • AGM 7pm
  • Refreshments at 7.30pm
  • Annual Lecture 8.00pm

Annual Lecture: Can the Cam Flourish Again?

Can we transform our water infrastructure and farming so we become part of a healthy aquatic ecosystem?

Professor Simon Spooner.

As AtkinsRéalis Fellow Simon is developing nature-based catchment solutions to flooding, water quality, water resources, biodiversity and carbon sequestration.

“Through the centuries we have been reaching ever further upstream for fresh water and dumping our waste as close to our doorstep as we can get away with.”

In his illustrated talk, Simon will present some innovative approaches to living sustainably with our rivers, focusing on enhancing the water cycle and fostering healthy aquatic ecosystems that are integrated with the land they flow from. This transformation demands a shift in urban planning and agricultural practices, emphasizing small-scale changes and investments by individuals and communities, alongside the necessary large-scale infrastructure projects by governments and corporations.

He will discuss the need for new business models, supportive policies, technologies, and collaborative contractual frameworks to facilitate these changes at the local level, inviting discussion on how we might implement such ideas effectively

What happens after Bathing Water Designation?

If the River Cam at Sheep’s Green becomes “Designated Bathing Water” in April 2024, the Environment Agency would start by monitoring the water quality every week during the 2024 bathing season to decide its official initial classification.  The bathing water season starts on 15 May.

Cam Valley Forum plans to provide a QR code at Sheep’s Green and other local swimming spots, giving a link to these official test results as they’re released (which is roughly once a week) so that swimmers can judge if they wish to swim.

In future years, the City Council would put up an official signboard at Sheep’s Green informing people about the Bathing Water Quality.   

We know from our own monitoring work over the last few years that the level of faecal indicator bacteria in the River Cam means that this initial classification will almost certainly be “Poor”, with “Bathing not advised” (although of course it’s still permitted)

Importantly, when there is Designated Bathing Water with a “Poor” water quality classification, this then acts as a statutory “Driver” requiring the water company to investigate the source of pollution and remedy it.

Anglian Water have confirmed to us that if the River Cam becomes “Designated Bathing Water” they will start by doing a “Source Apportionment” study to understand and uncover the causes of the problem. This will include looking at both their various assets (pipes, pumping stations and sewage works) and other 3rd party sources.

As Cam Valley Forum we will be very interested in the results of this Source Apportionment study.

We all expect that a big source of the problem will be the ageing and overloaded sewage infrastructure at Haslingfield.

Subject to the findings of the Source Apportionment study and approval of Anglian Water’s Business Plan by Ofwat they’re expecting to spend around £5M on improvements at Haslingfield, with work completed by 2027. The details of what needs to be done, will of course depend on what the source apportionment study discovers, but the overall aim is to improve the water quality in the River Cam at Sheep’s Green from Poor to Good

Without the statutory “Driver” of Bathing Water Designation, the improvements would be likely to take much longer…. maybe decades.

It’s going to take a while, but if we get Designation a cleaner Cam is within our grasp.

Do respond to Defra’s consultation by the deadline of 10 March

Defra Shortlists River Cam for Bathing Water Designation

Cam Valley Forum is very pleased that Defra announced on 26 February that Cam Valley Forum’s application for Bathing Water Designation for the River Cam at Sheep’s Green has been shortlisted.  It is one of 27 applications included in Defra’s statutory consultation

Anne Miller, Cam Valley Forum’s lead on this says “We will have to wait a few more weeks to hear if we will be granted designation, but this is a great step forward. A cleaner Cam is within our grasp”

We started working on this back in 2020, and last summer received overwhelming support in our formal consultation, with 517 responses, 93% in support. This included strong support from organisations including Cambridge City Council, Scudamores, Cambridge Canoe Club and the Cambridge Federation of Women’s Institutes.

Our surveys showed that hundreds of bathers enjoy swimming in the River Cam on peak days in summer, although, because the water is cold, one only sees a few people in the water at a time.

Designation is important because we know that the water quality is currently poor, and if Defra approves our application, this will trigger a ‘driver’ for much needed investment from Anglian Water. This investment will focus on understanding the sources of pollution and then (subject to approval by Ofwat) Anglian Water would invest to help clean up the Cam to help make it safer for swimmers.  Ofwat would typically require these improvement schemes to be in place by 2027.

 We know from our monitoring work over the last few years, that the ageing and overloaded sewage infrastructure in the Haslingfield area is a major source of the faecal pollution of the River Cam. This isn’t the only source of pollution of course, nor the only reason people can get sick, but we hope that as a result of Bathing Water Designation, it will become much safer for people to swim in the River Cam.” 

Michael Goodhart said

“The Town Bathing Place at Sheep’s Green has a history going back several hundred years, as a place where people could swim.  Back in the 1960s my family would picnic and catch tiddlers along Rush and float rafts in the paddling pool.  I was taught to swim in Snob’s Stream, before being allowed to dive into the main River Cam.  I still love swimming in the River Cam, as do so many people.  Bathing Water Designation provides a major opportunity for improving the quality of the river water for swimmers, boaters and also, very importantly we hope, for wildlife

Do respond to Defra’s consultation by the deadline of 10 March

How low can we go?

How can we reduce our water use, to help save our chalk streams?

Many Cam Valley Forum members are concerned about the health of our Chalk streams, so monitor their water use carefully. Some are already achieving water use well below average, ranging from 50 to 80 litres per person per day.  This compares to the current average use of around 150 litres per person per day, and the design target for new homes (specified in the draft Greater Cambridge Local Plan) of 80 litres per person per day.

To explore where the savings come from, some members have shared their water usage with us.  We have compared a careful ‘Low Water Use Household’, using around 50 litres per person per day, with a ‘High Water use Household’ using around 180 litres per person per day.

We estimated how much water they were using for different purposes and compared the households, as shown in the chart below.

Both households are 2 retired people living in homes with a garden. Other households may have different water usage patterns of course, for example if they have young children, or do a lot of mucky activities, or they’re out at work a lot of the time. Nevertheless the comparison is revealing.

Although the water efficiency of appliances affects water use, and their installation should be encouraged, the choices each household makes about how it uses water are often more important.

These choices, in order of importance are:

  1. hosepipes,
  2. showers and baths,
  3. the washing machine,
  4. toilets.

We looked at why the 2 households were using such different amounts of water for each of those key activities.

The Hosepipe. This is the most important differentiator, using about 170 litres in 10 minutes. This is why, even in summer the careful Low Water Use Household will very seldom use the hosepipe, typically instead collecting rainwater and water from the washing up (they do not use a dishwasher). This is then used for cleaning or to water the garden, as shown in this short video  

In contrast the High Water Use Household typically uses a hosepipe for 10 minutes a day in summer. Even in this short period the hosepipe nearly doubles the household’s water consumption, using more in 10 minutes than the Low Water Use Household uses all day.

Showers and baths are typically the second biggest differentiator between low and high water users. A modern water efficient shower head typically uses around 7 l/min. The two person Low Water Use Household shown in the graph takes 2 short showers per day, together totalling 5 minutes.   They seldom take baths, which use a lot more water than a shower. 

In the High Water Use Household the showers are estimated to take twice as long, at a total of 10 minutes a day for the 2 people. This consumes three quarters of the water that the Low Water Use Household uses for all purposes. If the High Water Use Household had a power shower or took regular baths (which can easily use 80l per use) their water use would be even higher.

The washing machine.  A typical modern, water efficient, washing machine uses around 43 l/load. The Low Water Use Household tries only to use the washing machine “when needed” which results in typically running one load per week. 

In the High Water Use Household, clothes are washed more or less every time they’re worn, resulting in the washing machine being used daily. As the graph shows this consumes half the water that the Low Water Use Household uses for all purposes in a day.

Toilets are the 4th most important differentiator.  While each flush of a modern low flow toilet uses around 4.5 l / flush (a tenth of the water that an old fashioned one uses) households make very different choices about how often they flush.  Typically, the Low Water Use Household only flushes “when needed” adopting the principle “if its yellow, let it mellow, if its brown, flush it down” flushing around 6 times a day.  

The High Water Use Household also has a modern low flush toilet, but flushes every time, estimated at around 10 times a day.   This simple choice means they flush away nearly half the water that the Low Water Use Household uses for all purposes.  Their water use would of course be much worse if they were also using an old fashioned toilet with a big cistern, which could use as much as 30l per flush.

As this shows, although owning water efficient appliances helps us reduce consumption, our personal choices usually make a much bigger difference.  Those using less than 80 litres per person per day can probably feel that they’re doing their bit to help save the Chalk streams.

Photo: Wild Trout Trust, Hoffer’s Brook Chalk Stream

However, it’s not sufficient to rely on the good will of a minority to help save our Chalk streams. This is why Cam Valley Forum is calling for Cambridge Water to introduce hosepipe bans (a.k.a Temporary Use Bans) every summer.

A senior Environment Agency manager has told us they are “surprised and disappointed” that Cambridge Water has not already introduced these.

If you’re not sure how to track your water usage, read this short article

How to track your water usage

If you don’t already have a water meter, ask your water company to fit one. This is free and typically reduces your bills by around £100 p.a. This is because those without a meter are assumed to be very high water users, and so the rates are set accordingly.   

Once you have had a meter installed (or you’ve found the one you already have, which will probably be near the stopcock for the house) the simplest way to see your water consumption is to look at your water bills. 

This will tell you what period the water consumption was measured over and give your water consumption in m3. You can then calculate the water consumption per person per day. Note that a cubic meter is 1000 litres. 

In the example given, the water consumption of the household is 20m3 x 1000 /185 days = 108 litres per day.  As there are 2 people in the household, this is 54 litres per person per day.

If you want more detail, you can read the meter.  It will probably look something like this:

This is showing a reading of 1071.81 m3 (look at the digits and ignore the dials) If you read the meter regularly and note the dates, you will then be able to plot a graph to see how your water consumption varies during the year.  

Here’s an example from one of our members.

They point out that their water use increased during the Covid-19 pandemic (as it did for many) and that it can rise over the Christmas period, when family members come to stay.  Nevertheless, their water use has never exceeded 100 litres per person per day and is generally around 50-60 litres per person per day. This is around 1/3rd of the average use, so they feel good that they’re helping save our Chalk streams.

To explore how people are reducing their water use, read our short article

More tea vicar? An unsavoury incident.

Cam Valley Forum hunts down a source of pollution in Vicars Brook

You’ve probably heard of Hobson’s Brook, the famous chalk stream which becomes Hobson’s Conduit as it approaches Cambridge towards the Botanic Gardens. However, fewer people know about its offshoot sibling, Vicar’s Brook.  It’s a charming little crystal-clear chalk stream that is supplied by water from Hobson’s Brook at two places.

Vicar’s brook, south

It runs alongside Empty Common allotments, through a long tunnel under the Trumpington Road/Brooklands Avenue crossroads, and continues along the side the Coe Fen cycle path, before emptying into the River Cam at Hodson’s Folly.

Vicar’s Brook, north

Shoals of silvery dace and roach, a hundred strong, can be seen dancing under the water surface.

But water clarity can deceive; invertebrate abundance and variety are not good.

Every few weeks, since May 2023, we have been sampling the brook at seven locations in the search for pollutants which could be responsible for the low invertebrate counts. There are numerous outfalls, several of them more than a foot wide, feeding into the brook.  Could any be polluting this beautiful stream and affecting its aquatic life? Samples are collected at regular intervals, or when a weather event occurs which may affect the flow of the stream and the outfalls which feed it.  These are analysed back at the CVF laboratory (a re-purposed dining room table in a house in Cambridge) for phosphate and E. coli.  

The CVF lab (a.k.a Richard’s kitchen)

Phosphate concentration is a key indicator of chalk stream health; high levels cause the stones and gravel to become coated by ugly filamentous algae. Sources include detergents (such as car shampoo), fertilizer use and sewage. A pristine chalk stream should contain no phosphate. E. coli on the other hand is an indicator of only one thing – animal poo, including human.  Measuring E. coli is actually pretty simple.  One millilitre of brook water is spread across the circular part of a E. coli specific petrifilm.  Incubating the films overnight allows the E. coli colonies to grow and reveal themselves as blue dots.  Ten blue dots on a petrifilm is equivalent to 1000 cfus/100 ml above which faecal pollution levels are considered “elevated“, potentially resulting in bathing water quality being designated as “poor”

Test samples from Vicars Brook on 21 November 2023

The blue dot count on the morning of 21 November 2023, however, turned out to be a real shocker, with the samples from points 5,6 and 7 way above the limit.

On seeing the result, our CVF sampler immediately trotted back to investigate the brook between sample points 3 and 5. It didn’t take long to identify the culprit; the outfall from the Brooklands Avenue surface water sewer was producing a very milky-looking effluent.  E. coli analysis of this outfall showed over 500 blue dots!

Brooklands avenue outfall, under normal conditions

We wanted to know the source of the E. coli. Although we’d previously bought a drainage map showing the surface drains and sewers in the area, the source of the pollution wasn’t clear. The best option was to report it to Anglian Water.  Pleasingly, within an hour of our phone call, AW technicans had arrived at the outfall and samples were being analysed using a handheld on-the-spot ammonia meter. Ammonia is also an indicator of sewage effluent. Although the milkiness had dissipated by then, the ammonia levels were still very high, much higher than surface drain water should be.

We spent the next few hours accompanying AW staff as they lifted manholes, diligently sampling and analysing as they moved along Brooklands Avenue. The probable culprit was finally identified as a construction works along Clarendon Road (most likely a misconnected portable toilet).  AW promised to resolve the source of the pollution. Several days later CVF was informed that re-sampling at the outfall had shown zero ammonia levels, indicating that action had been taken to resolve the leakage.

Do take the time to explore our lovely Vicar’s Brook, and look out for the shoals of dace and roach as you go, but do keep your eyes, and nostrils, open.  It needs looking after, and citizen science really can make a difference. 

To get involved, join us!