Nitrates in Cambridge’s Drinking Water

An email is going round to local election candidates about the level of nitrates in Cambridge Drinking water. This asks “What is the position of your party (Lab, Lib, Con, Green, respectively) on the high levels of nitrates in Cambridge drinking water?  Levels around are 50mg/L and unacceptable in any country in the world, never mind in a high tech city like Cambridge.”

We have been asked our view, and are sharing this here in the interests of political neutrality.

In summary, Cambridge Water Company (CWC) nitrate concentrations are higher than in some areas of the UK, because of the source of our supply, which is mainly the aquifer. However, even the maximum results from sampling of drinking water samples are well below the UK and WHO limit of 50 mg/l.  It’s loose talk to state that Cambridge levels are “around 50mg/l” and because of that are unacceptable.

The UK’s Drinking Water Inspectorate explains that “Drinking water extracted from rivers and boreholes in agricultural areas often contain nitrates. Very high amounts of nitrate in drinking water can cause methaemoglobinaemia (blue baby syndrome) in very young children. This is a potentially fatal illness where nitrate is converted to nitrite in the infant’s gut and interferes with the absorption of oxygen by the blood. This extremely unusual illness only occurs when nitrate intake is very high. The last recorded case in the UK occurred in the 1950s and was associated with the use of a shallow private well. However, cases still continue in other parts of the world where there is little or no management of water supplies. The first legal standard for nitrate was set in 1980 and the current drinking water standard is 50 mg/L. The UK standard is based on the World Health Organisation’s guideline value for drinking water, which is also 50 mg/L. This level is intended as a safeguard against methaemoglobinaemia.”

As CWC’s main supply is the aquifers, and this is an agricultural region, and as the aquifers have high concs of nitrate leaching down from soils, CWC’s supply source will also have high levels.  CWC maintains nitrate well below the directorate threshold of 50mg/l.  It has four nitrate-reducing plants for very high nitrate sources, and it mixes and blends appropriately. Results of testing for 2022 are on the Cambridge Water Company website here at 

Cambridge Zone 1 (north city) 39.741.4143.70
Cambridge Zone 2 (south city)37.741.1243.10
Anglian Water at Grafham village (2023)23.431.0240.28
Contrasts with Exeter3.716.8110.86

All values are nitrate (NO3) in mg/l

In contrast to Cambridge, where over 90% of our water comes from the chalk aquifer, in Exeter, over 90% of the water comes from lakes and reservoirs, for example on Exmoor and Bodmin moor. This is why Exeter has such low levels of Nitrates. Although Anglian Water also uses reservoirs for a proportion of their supply, the water sources here generally have much higher levels of nitrate than in the South West.

The calcium in Cambridge drinking water makes its health benefits much much greater than in those areas of acid water like Exmoor. Cambridge water also tastes better!

Note that the UK standard of 50 mg/l nitrate can also be expressed as 11.3 mg/l nitrate-nitrogen.  In the USA, the Environment Protection Agency standard is slightly lower, at 10mg/l, expressed as nitrate-nitrogen.    Some American reporting incorrectly states that the standard is 10mg/l nitrate, which will cause confusion to UK readers trawling the web.

In summary, nitrate concentrations in CWC supply are higher than in some areas of the UK, because of the source of its supply.  However, even the maximum results from sampling of drinking water samples are well below 50 mg/l.  It’s loose talk to state that Cambridge levels are “around 50mg/l” and because of that are unacceptable.

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.

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

Cambridge City Council formally supports Bathing Water Designation

We are delighted that Cambridge City Council will be supporting our application to Defra for Bathing Water Designation for the Cam at Sheep’s Green

This followed consideration by the City Council’s Environment and Communities Scrutiny Committee on 5 October, at which Councillors voted, 7 to 1, to formally support an application for Bathing Water Designation for the Cam at Sheep’s Green

We can now finalise and submit our application.

Anne Miller, Cam Valley forum’s lead on this says “I’m so pleased, and grateful for the hard work of everyone who has helped, since Jean Perraton and  Michael Goodhart started working towards bathing water designation back in 2020”

We are very hopeful that Defra will approve our application, and that this will unlock at least £5 Million in much needed investment from Anglian Water to help clean up the Cam. We know from the monitoring work over the last few years, that the aging and overloaded sewage infrastructure in the Haslingfield area is a major source of the faecal pollution of the Cam. This is resulting in such poor water quality that swimmers at times get sick, and it contributes to the phosphate pollution that is so damaging to habitats and wildlife. ”

“The investigation and improvements won’t happen overnight, but we hope that within a few years, it will be much safer for people to swim in the 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 allowing 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. “

Sheep’s Green in the 1970s

About bathing water designation for the Cam at Sheep’s Green

Cam Valley Forum will be applying to Defra for Bathing Water Designation for the Cam at Sheep’s Green, to improve the health of swimmers and help clean up the River Cam.

Summer evening at Sheep’s Green

Importantly, because the water quality is very likely to be offically rated as “poor”, designation should get us the investment we need to help clean up the river.

We are pleased to see that Anglian Water’s business plan, published on Monday 2 October, confirms this.  In it, on pages 174-6, they say that IF the Cam gets priority, by becoming “Designated Bathing Water” they are budgeting ~£5M to improve Haslingfield’s ageing and overloaded sewage infrastructure. We need this!

However to apply for Designation, we had to have a formal letter of support from the City Council.

Our consultation has shown that designation is overwhelmingly supported by the community. We received 509 responses to our 10 week online consultation, the vast majority from the local area. 93% were in support.  In addition to the City Council, we also have support from 18 organisations, ranging from Scudamores and Cambridge Canoe Club, to the Cambridge Federation of Women’s Institutes and South Cambs District Council.

The most common reason for supporting designation was wanting cleaner water in the Cam to reduce the health risks to swimmers and other water users.

The most common reason given for opposing designation, related to fears of significantly increased visitor numbers and that this would then damage precious habitats.

We share the concern to protect natural habitats, and much of our work is about preserving these. However, the fears of significantly increased numbers of visitors were in part due to rumours that the council would promote it as a visitor destination.  These rumours are incorrect.  Designation is simply about the health of bathers. There is absolutely no obligation to promote it as a visitor destination, so we are pleased that Councillor Sam Carling confirmed this several times during the meeting, and confirmed that the council has no intention of promoting it either.

Defra currently require us to submit 2 user surveys showing an average of at least 100 “bathers” on the 2 busiest days. Sheep’s Green has long been a popular bathing spot for communities across Cambridge, so our 2 surveys averaged more than 3 times this.  However, as few people stay in the water long, we seldom saw more than 12 people in the water at a time.

We think this will have minimal impact on habitats, parks and nature reserves

A fox and paddleboarders watching each other at Sheep’s Green

2023 bathing season record: 478 bathers at Sheep’s Green

A hot, but very pleasant day on Saturday 9 September, counting a total of 478 bathers in 4 hours at Sheeps Green. This is our record for the 2023 bathing season.

We already had two user surveys showing 184 and 278 bathers, which is well over Defra’s requirement of a minumum of an average of 100 bathers in 4 hours, in order to apply for Bathing Water Designation. However, as Saturday was forecast to be the hottest day of the summer, we decided to do another count.

As the afternoon temperature peaked at 32C, it was a joy to be in, on or near the river. We counted 478 bathers (ie swimmers, or children paddling) in just 4 hours.

Kids and adults swim from the quayside

Making a big splash

Teenagers congregate at Hodsons Folly

Small children and their parents enjoy paddling in the Rush

Worryingly, some people believe that the Rush is a fresh water spring (despite the clear notice saying that its river water). We were told someone had even been drinking from it. This is not a good idea (particularly as there’s a drinking fountain near the cafe)

Very pleasant on the grass by the quayside

and the Sheep’s Green picnic area was peaceful….

while the Lammas Land paddling pool was heaving

the Cafe was busy..

and as usual, a few people had parked in stupid places.

Successful Bathing Water Consultation Event

We held a well attended and lively consultation event on bathing water designation in Newnham Sports and Social Club on Tuesday 29 August.

Download the presentation here

Ably and fairly chaired by Jeremy Sallis (formerly of BBC Radio Cambridge), the room was packed with 62 attendees. A wide range of views were heard: Friends of the Cam handed out leaflets and spoke powerfully about their opposition to the principle of designation and their outrage at Anglian Water. Others spoke equally powerfully about the benefits of designation, particularly for the health of swimmers, Cambridge’s young people and their access to nature.

The main concerns related to increased visitor numbers. DBW would be a minor factor in increasing visitor numbers but there are a lot of other factors related to warming climate and less long distance travel for leisure that are likely to be stronger, given that the designation will result in advisories against swimming until improvements in quality can be achieved. Many people in the audience felt that visitor numbers to all green spaces in Cambridge are increasing and likely to increase for multiple reasons and this is good, and obviously will in the long-term need managing  – but this should not be stopping us cleaning up the river.

The overall feeling of the meeting was supportive of designation.

One participant emailed us with her reaction to the event as follows

Many local residents came along and put paid to the oft repeated fallacy that local people don’t want designated bathing water at Sheeps Green. The overall feeling was supportive……. every attendee received FotC leaflet, and I felt counterarguments most certainly were heard and given space to be expressed. Overall the takeaway was ‘don’t let perfect be the enemy of good’ – all these local pressure groups can and should campaign on many issues for better river health, changes to environment legislation and designation process, but just because DBWs don’t fix all problems all at once does not mean it’s not worthwhile.

Michael Goodhart, sharing some of the 400+ year history of swimming in the Cam

Anne Miller, explaining why Cam Valley Forum proposes applying for designation

Simon Spooner explaining how the water industry works

Olwen Williams sharing her concerns for Paradise Local Nature Reserve

Download the presentation here

Do respond to the consultation here by the deadline of 15 September 2023

184 Bathers at Sheep’s Green

Success! Having counted 184 bathers on Saturday 19 August, and 237 on Thursday 10th August, we now have the evidence we need to show Defra that there are sufficient bathers to qualify for Bathing Water Designation

Although it was a breezy day, so not as inviting for swimming as our previous count on Thursday 10th August, we still achieved well over Defra’s threshold of a minimum of an average of 100 bathers/ day, counted over 4 hours on the 2 busiest days of summer. Few people stay in long, so the river never felt busy.

It was a lovely afternoon, watching people enjoying themselves, and chatting with the swimmers.

This is an important place for people to come to for exercise
Artistic Swimming at Sheep’s Green

As it was a weekend, there were more punts, canoes and paddleboarders out on the river, than during the week, but everyone mixes along. Unfortunately Defra only allow us to count people as “bathers” if they actually go in the water at Sheep’s Green… But some did!

Wild swimming is a minority activity so, as usual, Lammas Land a few hundred meters away, was way busier. In late afternoon, we counted 149 adults and 110 kids there, with another 7 adults and 13 kids at the learner pool, ie 279 in total.

With just 5 people in the river at the time, this suggests that wild swimmers are only around 2% of the visitors to the area.

Lammas Land 19 aug 14:52

Do respond to our consultation here

City Councillors: please support a Bathing Water Designation application for the Cam

Cam Valley Forum urges Cambridge City Council to pledge to support a Bathing Water Designation Application for the River Cam at Sheep’s Green, because of the environmental benefits that it will bring.

This (shown in yellow) is the popular swimming stretch on council owned land, near the Lammas Land carpark, café, toilets and playground, Canoe Club, Learner Pool and Paddling pool. Subject to further consultations, we envisage applying for designation of the stretch from Hodsons Folly (just upstream of the footbridge) downstream to the popular childrens paddling area of The Rush. Our aim is to submit this in October 2023

A successful application would genuinely help clean up the Cam.

Cam Valley Forum has been campaigning for a Bathing Water Designation for the Cam at Sheeps Green since 2021. During the pandemic we carried out an initial consultation to understand the issues and counted bathers. Since then we have been monitoring the water quality, both as a citizen science project, and with Anglian Water. In September 2022 we were very pleased to see that Cllr Pippa Heylings’ motion about investigating a Bathing Water Designation was passed by South Cambs District Council.

A successful Bathing Water Designation application would have real benefits for both the environment and for residents.

As Surfers Against Sewage point out, “Bathing Water Designation shines a light on the water quality at a specific site which puts polluters in the spotlight. Once designation is granted there is a legal obligation for polluters to clean up their act and also a requirement that the government agency for your region tests the water quality throughout the bathing season. Your bathing water will be tested for Intestinal enterococci and Escherichia coli, otherwise known as E.Coli. At the end of the bathing season the designated site will be given a classification of: Excellent, Good, Sufficient or  Poor

If the quality of the water is “poor”, as our monitoring suggests the Cam will be, this will be publicised on the DEFRA swiminfo website (as in Oxford) This may deter some from swimming, but people need to know.

Importantly, the rating of “Poor” should also release the OfWat funding that will help fix the sources of pollution (we think Haslingfield Sewage Works is a major part of the problem).

We also think the City Council also has a moral duty to support an application. 

In summer hundreds of city residents a day enjoy swimming in the Cam, paddling in the Rush or jumping into the river at the Sheeps Green footbridge, while hundreds more enjoy the river on punts, kayaks, canoes and paddleboards, some of whom also fall or dive into the water at times.  We know wild swimming brings huge benefits in reducing stress, improving fitness and wellbeing and contact with nature. Importantly, its also free.  This is a vital source of recreation in our highly unequal city, with many city residents terrified about how they’ll survive the cost of living crisis.

Swimming at Hodsons Folly

A summer evening outside the Canoe Club

The Children’s Paddling Area at “The Rush”

Nevertheless we know the pollution level is frequently unsafe, and at times people become seriously ill. Swimmers at Newnham Riverbank Club further upstream and our rowing teams downstream are also affected. We think the City Council has a moral duty to support an application, both to inform swimmers about the state of the water, and because it will unlock the funding that will help provide a solution.

Although, during the pandemic, some were concerned that designation would result in swarms of visitors, we think this is most unlikely. Our likely rating of “poor” would be more likely to deter rather than encourage visitors.  Many other inland sites now have bathing water designation, including Oxford, the River Deben in Suffolk, the Serpentine in London and several Country Parks. Cambridge would just be one of many designated sites.

Surely we can’t let Oxford outdo us in taking serious action to clean up our river?

Sewage overflows increasing

The data thats just been released by the wonderful Rivers Trust, shows a concerning and increasing duration of Sewage Overflows from our local Sewage Treatment Works into the Cam and Rhee.

Haslingfield still has a high level of sewage overflows, although this may be due to problems with a sensor being incorrectly positioned. As the sensor was relocated in September 2021, shortly before Cam Valley Forum’s vist, we hope to see a very much reduced duration of overflows in 2022.

Melbourn overflows are increasing worryingly, which maybe explains why we saw very high levels of E-coli in the River Mel just downstream of the Sewage Works when we tested it on 19 January 2022. Anglian Water say this is due to “Ground water inundation”, but the River Mel Restoration Group are right to be concerned.

Concerningly, over the last 3 years, the duration of Sewage Overflows from Cambridge Riverside has been steadily increasing, although from a low level.

Fen Ditton Ditch clearance

The reservoir of the invasive weed, Floating Pennywort in the ditch between Fen Ditton ditch and the Cam has been in our sights for about a year. It is particularly important because now that the upper river is clear of Floating Pennywort, Cambridge Conservators are undertaking a major pennywort clearance project in the main river downstream of Cambridge. This ditch is now the main upstream reservoir.

Dealing with it has been a joint effort, led by Mike Foley.

Part of the problem was that a fallen tree was blocking access from the river, but ownership was unclear. It was clearly going to take a while to resolve, so Cambridge City Council lent us a boom to help contain the pennywort in the ditch until we could sort out what to do….

It took many many months, but finally, thanks to persistant hard work by Mike, much pouring over maps and many discussions with the Parish Council, various potential land owners and their agents,  Jesus College kindly agreed to “take responsibility” for dealing with the tree.

South Cambs District Council accelerated the permit for the treeworks as much as possible, but the nesting season had started before we got the OK to proceed. However, once Mike had done a Bird Survey to show that all was clear, Bidwells came in and removed the tree.The following day a team of 13 from Cambridge based technology company Sentec joined Mike to clear the pennywort.

They made good use of a set of nets and rakes given to us by the Environment Agency earlier this year.

The ditch is now basically clear of pennywort, although we will be continuing regular followup sessions from the bank and water to remove remaining strands as they emerge as the weather warms up.

If anyone who lives in the Fen Ditton area would like to help, do let us know.