By Colin Nicholson
Swimmers enjoying the water at Waldringfield January 2025
There continues to be much local and national interest and activity about the water quality of the River Deben. This interest has led to a huge increase in knowledge of what is going on where, but there remains much to learn. Below is a personal perspective of where we are now and further activity.
Introduction – “What is the Water Quality of The Deben?” and “Can I swim in the Deben?”
“What is the Water Quality of The Deben?” and “Can I swim in the Deben?” are questions that are often asked.
Concerns have been growing over the years, particularly since the post-covid explosion in wild-water swimming. Formal answers to these questions were difficult to come by, due to lack of firm evidence, but there has been increasing research in the past 3 years.
So now, in the New Year of 2025, we are in a significantly better position to answer the questions but it remains difficult to be absolute. Increased volumes and sophistication of testing is being carried out e.g. in more places; noting different times of tides; noting the amounts of rainfall before/after or at the time of testing.
What remains unchanging is the natural difference between the freshwater non-tidal Deben stretching 25 miles from its Debenham/Bedingfield headwaters to Ufford and the tidal estuary Deben, 8½ miles of saltwater from Ufford to the mouth at Bawdsey/Felixstowe Ferry.
Low flow in the non-tidal Deben (except when there is high rainfall!)…
The non-tidal freshwater Deben not only has no tidal-exchange but also can have its flow reduced by licensed abstraction by farmers. In dry summers, the “river” is sometimes described as a series of connected ponds, so low is the flow. The Environment Agency have a flow support borehole at Earl Soham which is licensed to provide flow support to the River Deben via the Earl Stonham watercourse based on a trigger (a combination of flow, water temperature and dissolved oxygen) in the non-tidal Deben as measured at Brandeston Bridge. Anglian Water also have a similar licence to provide support to the non-tidal Deben from a borehole at Debenham which is triggered by the same criteria as measured at Brandeston Bridge.
High flow in the tidal Estuary…
Meanwhile, the tidal estuary, benefits hugely from the sea coming in and going out twice per day, (estimated at around 7 and 17 million cubic metres per neap and spring tide – many Olympic swimming pools in common parlance!)
There has been a lot of public focus on “point source” sewage treatment works (STWs) and agricultural run-off, both very important on the non-tidal Deben, but a little-known fact is3:
“Because it is untreated sewage, one flush from a boat contains the same amount of bacteria as 250,000 flushes through the sewage treatment process”
Regulations regarding the discharge of sewage from boats are gradually increasing, however as yet there is no legislation which requires private pleasure craft to retrofit a holding tank. Although no specific provisions are made for smaller pleasure vessels in the UK, it is important for boat owners to consider the impact of discharging raw sewage from a sea toilet or holding tank into the sea.
Anglian Water has an ‘Advice to Boat Owners’ leaflet laying out best-practice: –
- “Plan ahead – use shore facilities before and after your trip whenever possible. This will avoid the need to use on-board toilets.
- Use your holding tank – if you have one, but only discharge it at a marina or harbour pump out facility or more than 12 nautical miles offshore
- Let your local marina/harbour authority know if you would use a sewage pump out facility if there was one.
- Use a portable chemical toilet – but plan ahead where you will empty it as they use toxic substances that only a few pump-out facilities will accept. Never empty chemical toilets into drains.”
On the Deben there are few pump-out facilities, but there is some provision at the Tidemill Yacht Harbour and Robertson’s boatyard.
Large sand smelt
“Can I swim in the Deben?”
General Wild-Swimming Advice…
Sensible advice for swimmers and other recreational users says that they should cover any cuts and grazes before their activities and shower afterwards4. However, along the whole length of the Deben, there are few showers, other than in the private sailing clubs. There is also a distinct lack of public toilets. (Perhaps this should be the topic, along with pump-out facilities, for another more mundane but nevertheless important, RDA Journal article).
In the non-tidal Deben…
In the non-tidal Deben, it is mostly the case that water quality in those areas tested does not meet the Environment Agency’s standards for inland designated bathing areas [Appendix 2]. But helpfully, at the popular bathing spot at Hawkeswade Bridge, Ufford, (Ufford Hole,) the Ufford Parish Council is in the habit of putting up a warning notice (a practice started in summer 2022) when the quality does not meet the Environment Agency’s Designated Bathing Water standards (based on DCC’s twice-weekly testing throughout the bathing season, weekly through the rest of the year Link to ITV Anglia News item). The notice is helpfully removed when the water returns to safe levels. The DCC has been testing since 2021 and thus information is provided upon which to make an informed decision on whether to swim.
In the tidal estuary Deben…
People swim and do other recreational activities at Woodbridge, at the Rocks, at Waldringfield, at Ramsholt, at Felixstowe Ferry, at Bawdsey and elsewhere, as well as swimming off their moored boats and inadvertently swimming when their dinghies or canoes capsize. However, rather than water quality, the safety of estuary swimming is probably more to do with the danger caused by the speed of the tide (certainly for the uninitiated) and the dangers of moving boats (a particular hazard at busy Woodbridge, e.g. with the sight-seeing boat coming into the pontoon near where wild-swimmers congregate).
The most detailed picture of water quality in the estuary is available at Waldringfield.
In the Estuary’s Designated Bathing Water Area at Waldringfield…
“Good” is the current rating (Link to their Nov 2024 report5) by the EA – their summary for bathing water quality at Waldringfield, made up overwhelmingly of ‘Excellent’ results – but with occasional spikes.
Waldringfield where designated bathing water status has been granted
The May 2023 Bathing Water Designation at Waldringfield has resulted in now a full two years-worth of summer-bathing-season weekly EA tests (2023, 2024). Across these two bathing seasons, 38 out of 40 EA E.coli tests rated ‘Excellent.’ (i.e. all bar two 2023 outlier events or spikes, see [Appendix 1] for detailed results and [Appendix 2] for ratings explanatory table).
Following-up on these two E.coli spikes in the 2023 bathing season, one was ‘Good/Sufficient’ and one was (very) ‘Poor.’ Because of the discrepancy, the EA sent samples (the two spikes, and one further sample,) for in-depth MST ‘Microbial Source Tracking’ analysis to identify potential sources. The relevant quote from the EA’s analysis report (Link) is: –
“The Environment Agency can use a DNA tracing technique to identify whether sources of pollution are human or non-human. Analysis of three samples taken in 2023 showed clear evidence of faecal pollution from seabirds; human signals possibly from non-faecal waste sources e.g., misconnections from washing machines, showers, hand basins and faecal waste sources; possible signal from pigs and clear evidence of dog DNA. The DNA technique cannot yet be used to ‘source apportion’ and DNA markers are not yet available for all species (for example seals). The high sample taken in September 2023 was taken on an astronomical high tide and parts of the shoreline not usually submerged were covered by tide. Bacteria that would not normally enter the watercourse would have been washed in. It is possible this bathing water will be affected by high tides, but the Environment Agency will continue to investigate this”
Interpreting the EA’s quote,
- MST analysis pointed away from human faecal waste sources
- The poor-rated sample was taken during an astronomical high tide and a possible explanation might be the more occasional “washing” by the highest tide of the highest parts of the beaches with faecal pollution from seabirds and domestic dogs being walked with their owners failing to clear up.
- A low amount of human bacteria was detected in the sample. This, along with no cattle, no sheep, no bird mitochondrial DNA, would suggest very limited evidence for sewage/human wastewater. This also supports the signal from pigs. It would be expected to find low levels of cow, sheep, pig and bird (chicken) in typical wastewater; finding one only would suggest a contribution from that source.
- For human signals in the sample, there was more mitochondrial DNA in the sample than human-faecal bacterial DNA. This could suggest non-faecal waste sources e.g. misconnections from washing machines, showers, handbasins. This could have also come from people swimming in the water at the time. Waldringfield was busy when the sample was taken.
Throughout the 2024 bathing season, EA E.coli tests were ‘Excellent with no spikes, but it must be mentioned that almost immediately after the end of the bathing water season, and thus after the EA had stopped their weekly testing, the DCC identified another significant spike of E.coli (7th October 2024, [Appendix 3] and link to DCC’s Facebook page). But within DCC results, this spike was also an outlier as their readings at Waldringfield in the months both before and after this spike were closer to their usual readings [Appendix 3 for December 2024 example]. DCC helpfully alerted the EA to the October spike and the EA are investigating. (Additionally, on 5th August 2024, DCC identified a spike at Ramsholt and also reported this to the EA).
In the Estuary but at Martlesham Creek…
However, in Martlesham Creek, with low river (Fynn) flows, lower tidal-interchange within the creek and the continuous output of the Martlesham Sewage Treatment Works (STW,) it seems inadvisable to swim in Martlesham Creek at any time including high water. The EA advice for coastal/transitional waters [Appendix 2] is that it is unsafe to swim in water where the E.coli level is over 500 CFU’s per 100ml / 5 CFU’s per 1 ml. Martlesham STW regularly emits over 100 times that level so even with tidal dilution the risks are not worth taking.
Permit levels certificate for Martlesham STW (Sept 2022)
Whilst Martlesham STW rarely breaks its EA permits, there are actually no maximum levels for E.coli from a STW (as E.coli is not significantly harmful to aquatic life, one of the original factors behind the structuring of the regulations).
Indeed, the July 2024 RDA Fish Survey found results ( in and around a small creek sitting within the new Martlesham Wilds Nature Reserve adjacent to the Deben estuary near Martlesham Creek,) entirely consistent with the type of fish community found in the upper reaches of estuaries in the Southeast of England and agrees with findings at other sites in the upper and middle reaches of the Deben estuary in past years. Underlying the good news, there were numbers of juvenile sand smelt and fish fry present in catches (which were identified, measured and returned,) both known to be sensitive to pollution. Further, it seems salinity is a prime driver of the difference in distribution between the fish communities at Bawdsey and Martlesham Wilds1.
Setting the winged fyke at Martlesham Wilds Nature Reserve
Site plan for citizen science sampling at Martlesham Wilds Nature Reserve
However, at Kyson Point the DCC regularly get unsafe (as laid out by the EA for bathing water designated areas,) readings even at high water. Here, it seems advisable that people check the tide time before swimming and aim to swim 2 hours ahead of high water and one hour after.
Kyson Point
So, what does this mean for swimming…
The Bathing Water Regulations 2013 set out how the EA must sample and when. A monitoring calendar is established prior to the start of every bathing season. Sampling must start just before the season, be scheduled across varying tide heights (varying times before/after High Water) with varied collection times and include some weekend and bank holidays, when the largest number of bathers are often present.
With EA testing at Waldringfield taken at all stages of the tide, [Appendix 1] there seems little evidence that predicates bathing to be better at any particular stage of tide calling into question the notion of it being better to swim up to 2 hours prior to high water (although this timeframe makes it easier to get to the water avoiding the silt!)
But taking into account the evolving information about spikes, it seems advisable to avoid swimming around super high tides and when there has been significant rainfall leading to agricultural runoff (cows/pigs etc.) and the potential for combined sewage (CSO) overflows should the sewers get overwhelmed. As with so much, it is up to individuals to make their own decisions.
More work needs to be done to understand the origin(s) of these spikes and, of course, different spikes may have different causes. The EA and DCC continue with their testing. Anglian Water have included provision in their latest budgets for a Bacterial Source Apportionment Study, expected to take place from 2025 to 2027 with results having a bearing on the investment case for building a tertiary treatment stage at Martlesham STW.
Water Quality
In the Non-Tidal Deben …
In the non-tidal (freshwater) Deben the main sources of E.coli are the Anglian Water STWs. Other contributors are Agricultural runoff (livestock/arable) and private STWs.
Cow in Deben between Ufford and Bromeswell
E.coli levels in a non-tidal (freshwater) river can often be higher, (not lower due to dilution,) following heavy rainfall because in these ‘high flow’ conditions there is a greater risk of contamination from agricultural run-off and a range of other non-water company sources such as urban pollution.
Phosphates and nitrates in the Non-Tidal Deben …
Whilst there are no maximum levels set for E.coli discharged from STW’s, there are EA permits for phosphates and nitrates. Natural England has a “healthy river” guideline of 0.1 mg/ litre maximum. EA permitted levels at most non-tidal Deben STWs have been tightened recently and the new limits came into force at the end of 2024. These led to Anglian Water fitting phosphate removal machinery at most of the main STWs, which had a dramatic effect. (See Appendix 4 for list of STWs and EA Permit limits)
Anglian Water wrote general (non-Deben-specific) comments on Phosphate levels in their 2023 ‘River Health’ report that came out in June 2024 and these comments align with the results being seen on the non-tidal Deben.
“At Water Recycling Centres with new or existing permit limits for phosphorus, we will have reduced levels entering rivers and streams in our region by 53% on 2020 levels.”
The main sources of phosphates and nitrates in the non-tidal Deben appear to be Agriculture run-off, (Livestock & Arable); Anglian Water STWs; Urban runoff; Private STWs; groundwater.
In the tidal estuary Deben…
Phosphate and nitrate levels, in addition to E.coli, provide information as to the wider health of the estuary. As for the non-tidal Deben, phosphates and nitrates emanate largely from agricultural run-off and STWs, but some emanate from the soils around the estuary. Indeed, Fisons, at one point one of the world’s largest fertiliser producers, began its fertiliser production around the Deben Estuary, using phosphates from the soils.
However, in contrast to the non-tidal Deben where phosphates play the key role which leads to eutrophication, in the non-tidal estuary it is nitrogen that is normally the nutrient which leads to eutrophication. Whilst phosphorus still plays a part, as both nutrients are essential to growth, it is nitrogen that is more likely to be the critical, limiting factor in estuaries i.e. if you reduce nitrogen you will reduce impacts of eutrophication seen by excess macroalgae growth. (There remains some scientific debate as to the importance of phosphorus). This may be dependent upon the particulars of an estuary, the transition from fresh to saline water.
Nitrogen enhanced eutrophication isn’t confined to the Deben estuary; it occurs in many sheltered, muddy estuaries along the coast where conditions are suitable.
Likely main sources of nitrogen in estuaries are diffuse (as opposed to point sources like STW discharges,) such as agriculture within the river and estuary catchment. Another source in the estuary could be ‘coastal background’ nitrogen that enters on each tide from the sea. However, there will be some nitrogen from STWs and other urban diffuse sources.
In 2023 Natural England reported the “Natural England whole habitat feature condition assessment of Deben Estuary SSSI” as “Unfavourable Declining” down from its previous 2010 “Favourable” rating.
The ‘Recovering the Deben’ project (see below) has produced a project brief for water quality investigations within the estuary. This project will look at eutrophication within the estuary, source apportionment of nutrient loadings and potential impacts on habitats, making recommendations for further research and the development solutions to bring the Deben SSSI back to ‘favourable condition.’ Recovering the Deben’ are working with Natural England’s SSSI team to gain their approval/insights before making a formal submission in early 2025.
What we see (and smell!) – the visible signs relating to water quality/pollution – or not!
Phosphates and nitrates
Phosphates and nitrates increase the growth of macrophytes and algae, which can smother the water’s surface. For instance, duckweed (Lemna sp.) blocks sunlight from reaching the plants at the bottom, which die. The dead plants provide food for microorganisms, which consume oxygen and deplete the water’s oxygen levels which can lead to reduction in aquatic life. This enrichment of water by excessive nutrient is known as eutrophication.
Hawkeswade Bridge, August 2022
Nitrogen is a plant nutrient but too much of it in estuaries can lead to excessive growth of opportunistic green seaweed (also called macroalgae). This effect can be seen at low water as thick green seaweed mats covering the intertidal mudflats of the estuary. As well as looking unsightly, it affects amenity (e.g. clogging boat propellers or washing up on slipways) and can adversely affect the birds that feed there (because their bills cannot penetrate the weed to feed or because the weed changes the availability of their mud-dwelling prey items).
When the seaweed breaks down, either after a period of rough weather or at the end of the growing season, it can give off unpleasant smells typically that of rotten eggs or vegetables, which can sometimes incorrectly be attributed to sewage pollution.
Nasty looking scum – not caused by sewage…
In May 2024 there were reports of scum on the water just off Whisstocks. The EA were called and their investigation found that as there were very low levels of ammonia, the scum was not caused by sewage. The scum was caused by natural algae and the EA’s report stated: –
“Algal ‘sloughing’ is a common occurrence at this time of year [May] and looks like a floating mass of frothy scum on the surface which is often mistaken for sewage or slurry pollution. During warm weather, photosynthesis causes tiny oxygen bubbles to form on algae on the bed of the river which then rise to the surface. Whilst it might not look pleasant, clumps of algae are usually harmless. The oxygen levels in the river are not normally affected and the scum will disappear naturally over time.
Sewage usually presents itself as grey and cloudy in a watercourse as the majority of sewage water is from sinks and showers rather than toilet waste.”
Environment Agency
Nasty looking blanket weed/ green algae…
In July 2024, during a warm spell, there was significant overgrowth of blanket weed/algae off Woodbridge, Microscopic amounts of algae are always present in the water, but in the right conditions, (including warmth, increased sunlight, with low wind so algae is not broken up by wave action) algae rapidly blooms – but these blooms are made worse by phosphates and nitrates, (in effect, fertiliser!)
Opportunistic green algae Woodbridge Tidemill July 2024
Testing and Testers
The Environment Agency’s most publicised tests along the Deben are those at Waldringfield (see above) which achieved Bathing Water Designation in April 2023 following a campaign and submission by the ‘Save the Deben’ group. That designation triggered a statutory requirement for weekly Environment Agency (EA) testing during the May-September Bathing Season. (A government consultation has taken place recently on whether this testing period should be extended to all-year-round). The EA test the length of the Deben but it is difficult to find and understand their results outside of Waldringfield.
E.coli and enterococci bacteria are known as faecal indicator organisms or FIOs and the specific ones that the Environment Agency test for are Escherichia coli or E.coli (EC) and Intestinal enterococci (IE). These bacteria can come from many sources including sewage, agricultural livestock, wildlife, birds and road drainage7. Water is tested for E.coli and coliform bacteria as indicators of faecal contamination, rather than testing for specific viruses, because it’s less expensive and time-consuming. Coliform bacteria are usually present in larger numbers than viral pathogens, and respond to water treatment similarly.
The Deben Climate Centre (DCC) started their water quality testing in 2021 and has now built an impressive regular testing capability (‘Safari’ on the first Monday of the month,) from the source of the Deben near Debenham to the Wilford Bridge and more recently the estuary section down to Bawdsey. It also tests feeder rivers to The Deben, such as the Lark and Fynn. More than 50 volunteers are involved, testing more than 60 locations and the DCC now publish their results monthly on Facebook (Link).
The testing regime is building from E.coli, enterococci to include levels of nitrate, phosphate, dissolved oxygen, temperature, pH and turbidity. Their testing is delivering a clearer picture of where high levels of e.g. E.coli, phosphates etc, are occurring and, in work with Dr Nick Tucker of the University of Suffolk, the presence of toxins and antibiotic resistance in E.coli strains has been demonstrated (link to a BBC Look East news item on YouTube) a finding similar to other rivers.
Like the RDA below, the DCC is starting to monitor Riverfly at nine locations other than Hawkeswade Bridge, including Ufford, Little Bealings, Rendlesham, Wickham Market, Easton, Kettleburgh and Earl Soham.
The River Deben Association has conducted regular citizen science Riverfly monitoring (e.g. mayflies/caddis flies) since summer 2023 at Hawkeswade Bridge, in association with the Environment Agency. Riverfly monitoring is second order monitoring for water quality. A pollution incident might be missed (having passed by already,) by a weekly testing regime, but a serious, even if quick, event will have lasting consequences on the Riverfly population.
The RDA is supporting the monitoring of other ‘second order’ indicators of water quality: the number of Otters (observed with camouflaged cameras by the Deben Otter Group, cameras at six points along the Deben, some donated by the RDA, link) and fish numbers (the RDA and Suffolk Wildlife Trust in 2024 supported the third year of a fish survey off Bawdsey and Martlesham1 (Link to 2023 Report).
‘Save the Deben’ conduct testing in the estuary, often in conjunction with ‘Surfers Against Sewage’ and during September 2024 carried out a focused week’s testing at Waldringfield. Their volunteers took water samples every day with the University of York analysing them for a wide range of substances. Commenting on this testing, Ruth Leach, co-founder of the ‘Save the Deben’ campaign group, said: “The river water was sampled two hours before high tide which is when the water is accessible to our swimmers. The effect of tidal dilution meant that we were clear for E.coli but the findings of other chemicals is concerning. I am advised that the levels of the pesticide cypermethrin and the pharmaceuticals; metformin (for treating diabetes), paracetamol(painkiller), and gabapentin(anticonvulsant) were not high enough to pose a threat to humans but we don’t know what effect their presence is having on the biology of the river or in fact what the combination of medications could be doing to wildlife such as fish and invertebrates.”
Anglian Water has committed to an independent ‘Quantitative Microbial Source Apportionment’ (QMSA) study of the Deben with plans to commission in 2025. Separately, investment in reducing combined sewer overflow (CSO) spills is planned, regardless of the outcomes of the bathing area test results and QMSA study because this investment helps protect the ecological status of the Deben.
Moving Forward, a project to ‘Recover the Deben – from source to sea’
And how do we move on from monitoring to changing things for the better? One of the answers is the ‘Recover the Deben’ project supported by the East Suffolk Catchment Partnership, launched in May 2024 completing 2030, which has the support of DEFRA and the EA and is working on the key issues across the whole Deben Catchment that prevent the river from meeting good ecological status.
One project within ‘Recover the Deben Source to Sea’ is to develop buffer strips, vegetated areas, often wooded, that lie adjacent to the river and act as natural biofilters, trapping sediments, nutrients and pollutants that could otherwise degrade water quality. Other related actions would be to fence off the river so that livestock cannot enter and pollute the water.
The ‘Recover the Deben’ project’s full Objectives and Timings are at Appendix 5.
In Conclusion…
In conclusion, for the swimming question, it is possible to undertake swimming and other recreational activities in the Deben Estuary and in the non-tidal Deben at Ufford.
With regards to water quality… in the non-tidal Deben further work is required to improve overall water quality amongst other river improvements. And, for the tidal estuary, more data is required to enable attempts to pin down the causes of the pollution spikes, particularly at Waldringfield, so that, where possible, these can be predicted and communicated to participants to support untroubled, fulfilling wild-water swimming.
Colin Nicholson
Appendix 1: 2023/2024 Waldringfield E.coli official readings (taken by the Environment Agency)
(with unofficial addition of time of High Water; Tidal Range; time of test cf High Water)
Appendix 2: EA Bathing Waters Directive Classifications
Appendix 3: Woodbridge Data: 7th October 2024 Spike and “Routine” December 2024
(with thanks to the Deben Climate Centre)
7th October 2024 – Spike
“Routine” 1st Monday of the month Dec 2024 “Safari”
Appendix 4: Environment Agency Phosphate Permits – January 2025
| Sewage Treatment Works | Phosphate Permit mg/litre |
| Debenham | 0.5 |
| Earl Soham | 0.9 |
| Charsfield | 4.0 |
| Easton | No max |
| Wickham Market | 1.0 |
| Rendlesham | The Rendlesham permit is for 1.0 mg/ litre and comes into force on 31st March 2027; there has been a delay in installing the phosphate removal technology here. |
Appendix 5: Recover the Deben Project Objectives and Timings
Project’s objectives are: –
- To work with farmers to improve livestock management to reduce impact on the river catchment
- To promote better nutrient management in agricultural and waste water discharge
- To engage with farmers, industry, and communities to help educate and understand where improved soil and water management is needed
- To improve river resilience to low and high flows
- To enhance wildlife habitat quality and connectivity across the Deben landscape
Project’s timings:
| Step 1 | Establish governance | By end of 2023 |
| Step 2 | Gather and evaluate evidence against objectives | By mid-2025 |
| Step 3 | Engage landowners, industry, and communities | Throughout duration of project |
| Step 4 | Action Planning | By mid-2026 |
| Step 5 | Deliver the plan | By end of 2030 |
Appendix 6: Other resources
River Deben Estuary, Waldringfield (Link to EA On-Line summary)
2024 Bathing Water Profile for River Deben Estuary, Waldringfield
Bathing Water Directive: Coastal or Transitional Water
EU Directive concerning the management of bathing water quality
Reforms to The Bathing Water Regulations 2013 – GOV.UK
Consultation description
We want to know what you think about:
- removal of automatic de-designation after 5 years of ‘poor’ water quality
- changes to the designation criteria of bathing sites
- removing the fixed dates of the bathing season from regulations
We also need your views on proposed technical amendments, as well as potential upcoming reforms on:
- the definition of ‘bathers’
- the introduction of multiple monitoring points at bathing sites
National Storm Overflow Hub for England
The NSOH map provides near real-time information about storm overflow discharges in England, as indicated by event duration monitors.
You can use the map to see if our monitors indicate if a storm overflow is currently discharging and the date and time of the last recorded instance of them discharging. The data received from our monitors isn’t always accurate (for example where a sensor has been activated by another cause). That means the data here does not confirm definitively if a storm overflow is discharging, it only provides an indication.
“We want our information to be accessible for water users to be able to make an informed decision before entering or using the water. This should not be considered as advice on bathing water quality.”
Environment Agency’s national “Swimfo” website
Environment Agency’s information on bathing water quality
Government’s Health Security Agency’s guidance for Wild Swimming
References
1 Deben Estuary Citizen Science Fish Survey Programme, Bawdsey Beach and Martlesham Wilds Nature Reserve, Institute of Fisheries Management, July 2024
2 https://theriverstrust.org/sewage-map
Treated Sewage Discharges explanation
3 https://www.anglianwater.co.uk/SysSiteAssets/household/help-and-advice/led603-boating-near-bathing-and-shellfish-waters.pdf
This statistic originates from https://thegreenblue.org.uk an organisation set up by British Maritime and the Royal Yachting Association to promote “Sustainable Boating for Cleaner, Healthier Waters. Helping the boating community to safeguard our coastal and inland waters.” The statistic is used in the ‘Boating near Bathing and Shellfish Waters’ Anglian Water Services leaflet. However, the statistic probably relates to STWs with “Tertiary Treatment” installed (an expensive extra stage of Ultra-Violet treatment,) which is not the case for any of the STW’s on the length of the River Deben.
4 How to stay healthy while wild swimming – UK Health Security Agency
5 Waldringfield Nov 2024 Report by Environment Agency
The Waldringfield ‘page’ of the EA’s national “Swimfo” website
6 Anglian Water 2023 River Health report (released June 2024)
On p5
“By the end of 2025, our phosphorus reduction programme will improve river health across 104 waterbodies, including removing 165 confirmed, probable or suspected RNAGS (Reasons for Not Achieving Good Status). At Water Recycling Centres with new or existing permit limits for phosphorus, we will have reduced levels entering rivers and streams in our region by 53% on 2020 levels.”
7 https://environment.data.gov.uk/bwq/profiles/help-understanding-data.html
‘Bathing Water Quality’ by the Environment Agency
Thanks
Thanks to many experts for their support and to Ruth Leach Photography for some of the photographs