Risks and myths at Bawsey Lakes

… and how to stay safe and avoid genuine risks

The owners of these beautiful lakes in West Norfolk make it clear that they do not wish people to swim or paddle, and that they consider to do so is dangerous. However, in reality these lakes have no special factors that make them dangerous, and in fact they are safer than many alternative outdoor swimming places such as the sea, tidal rivers or other rivers. Outdoor swimming (here or elsewhere) does have real risks, which can be dealt with by understanding how to stay safe.

Using our detailed understanding of safety and expert sources, swimmers have assessed the site using a variety of methods as thoroughly as possible. We have examined each claim or risk in turn to try to establish whether it is a real risk or a myth and explained how to mitigate any real risks. The most effective way to enable people to keep themselves safe is to give them accurate information on risks and how to stay safe.

The page details each risk or claim, explains whether it is a myth or a risk and how to stay safe. Please note that this list of risks is not intended to be an exhaustive list of all relevant risks, and please note the statement on liability at the bottom of the page. You can also download this page as a document (Word.docx 9 pages)

Index to sections

Risk or “Claim”; Myth or Risk; How to stay safe


Cold can be a real risk, here or in other open water, and it’s important to understand the risks and how to tackle them.

“Cold water shock will kill in minutes, any season, age or fitness   

This claim has an element of truth, but doesn’t tell the whole story, nor does it explain how to avoid coming to harm. Cold water shock is a real risk of outdoor swimming, and it is true that it can affect anyone regardless of their age or fitness, and can occur in any season, though much less likely once water is above 15°, as it will be throughout the summer. It is true that it can kill in minutes or even seconds – if someone unused to cold water enters the water too quickly and especially if they put their head straight into the water. This is because it can cause an involuntary gasp, and if your head is under water when this happens you will take in water and can drown. The shock of cold water can also increase heart rate, which is not generally an issue unless somebody has a heart condition. Those used to cooler water are less likely to experience this because of acclimatisation, unless the water is much colder than they expected. If swimming in a wetsuit, cold water shock can be experienced when water enters at wetsuit, and if out in a lake that could cause issues including panic. Cold water shock is actually one of the aspects of outdoor swimming that creates important benefits – the minor stress of carefully controlled exposure to cold can make people more resilient to other stresses in their lives.  Read more, in Chill, a book by expert on cold water, Dr Mark Harper. Or in this YouTube video he talks about the benefits and how your body reacts and adapts to cold water. Or listen to Prof Mike Tipton on BBC Sounds explain the risks and benefits of cold water shock, managed carefully.

Problems are easily avoided by entering the water body first, not too quickly, and not swimming off until breathing has calmed down which can take 1 to 3 minutes. If starting off outdoor swimming, especially in cooler seasons, best to be aware of medical condition especially in relation to the heart. If wearing a wetsuit, be sure to allow some water into the wetsuit and wait until used to the impact of that cold before swimming off. If not used to cool water, don’t go out into a lake on an inflatable to avoid cold water shock if you fall in. Practice Float to Live, so that you can do it automatically if you panic or fall into water. Lie on your back, like a starfish, with your ears in the water, move your arms and legs gently if necessary to stay afloat. See how on Respect the Water

Other risks of cold: Swim failure/ cold incapacitation/ stealth chilling  

This is a real and important risk, not mentioned enough or understood. Deaths resulting from this can mystify as it can affect swimmers of any ability, but it can easily be avoided with knowledge. If you get cold your muscles don’t work as well, because the body is concentrating blood flow to your core. If you’re in the middle of a lake it can be very hard to get back, and you can sink into the water and drown. Treading water or trying to swim will mean your position becomes more upright making it more likely you will sink into the water. http://www.outdoorswimmingsociety.com/cold-incapacitation/

If not used to cool water, stay near to the shore or do short trips out and back, or stay within your depth, and get out before you get too cold. If you find your muscles not working well, turn onto your back and Float to Live, call for help, and use your feet to paddle you back to shore. Wetsuits can delay stealth chilling and the buoyancy they give can help keep you afloat, but they do not fully prevent swim failure. Swimmers need to be aware of their body and how it responds to cold, and to know when they need to get near to the shore ready to get out.

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Other risks of cold: After drop

More likely in winter, but possible any time of year. After you get out of the water your body continues to cool for 10 to 40 minutes. At the most extreme this could lead to hypothermia, but is easily avoided,  https://openwaterwheway.wordpress.com/2022/11/11/afterdrop-the-post-swim-shivers/.

Don’t stay in too long and get too cold (and swimmers have to learn how their own body response to cold).  When you get out of the water, don’t hang about, but get dry and put on warm clothes, at least one layer more than you might think you need, and do some gentle exercise. Some consider that wetsuits slow down the process of getting wet clothes off in order to get dry and warm.

Other risks of cold: Hypothermia

This is when the core becomes dangerously cold. It can take a while to develop, and someone might not realise it is happening and might even think they are too warm. Signs of hypothermia (IN the water) can include: Shivering, change in swimming technique or speed, unable to speak, growing more vertical in the water, fingers becoming splayed. blue around the lips. Signs of hypothermia (OUT of the water) can include: Grumbles – negative mental outlook. Fumbles – slow reaction time, drops things, poorly coordinated. Mumbles – slurs words. Stumbles – appears stiff, loses coordination, difficulty walking.  www.outdoorswimmingsociety.com/understanding-hypothermia/

Don’t stay in too long and get too cold when swimming, get dry, dressed and warm after you get out. Be aware of the signs of hypothermia (the ‘umbles’) in yourself or others, be firm with another person who needs to get out of the water and get warm, know how to warm yourself or someone up, and know when to call for help. Wetsuits can delay but cannot prevent hypothermia.

Windy conditions

This could make it much harder to swim against the wind, especially if that is your return journey when you are tired and cold. There are no currents in these lakes, however windy conditions could create similar issues. Wind can also make you colder, especially when changing afterwards. Inflatable toys or boats can be blown out from the shore into the lake, and someone on them that cannot swim and does not have a life jacket or is not used to the cold that could be at serious risk.

Be aware, factor this in if doing a swim away from the shore. As usual in cold conditions, get dry, dressed and warm as soon as you get out of the water.   Avoid using inflatables if it is windy, supervise any non-, weak or inexperienced swimmers.

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“Deep water, sudden shelving into deeper water”

Some shores of the lakes can shelve, but not the beaches at Bawsey Bay or the western side of the Great Lake, or the beach at Brickyard Lake. Suddenly going out of your depth can be a real risk, particularly for those who are not confident or good swimmers, also for those paddling.

Be aware when entering the water, supervise non-swimmers or weak swimmers or children in your care. Only go into deeper water if you can swim. If not confident, stay within your depth.

“Steep sides making it hard to climb out, especially if cold”

This does not apply at most beaches at Bawsey, but the swimming ban might mean people trying to swim from more hidden and steeper places, and it is true that it could be hard to get out especially when cold, leading to getting even colder.

Be sure you know where to get out before getting in to swim, and it is best to choose shallow gradual entry and exit points. Be aware that being too cold can affect muscles especially fingers and hands.

“Deep water will be cold”

It is true that the deeper levels of lakes can be colder, but the water has different temperatures at different layers, and in certain seasons they mix. Someone jumping in (not a good idea anyway in these lakes) could enter unexpectedly colder water. In spring and summer the top layer of water warms up, reaching more than 20° in summer, and this layer will be deeper in larger bodies of water. Swimming happens in the top metre, which is likely to be warmer. In winter the opposite is true, and the top layer can be the coldest, but winter swimmers are likely to be aware of this. www.outdoorswimmingsociety.com/thermal-layering/

Best to avoid jumping into these lakes. Be aware of possible variation in temperatures, and of the risk of swim failure/cold incapacitation – swim parallel to the shore unless experienced and used to cooler temperatures.

“Very cold water, even in summer, freezing temperatures beneath the surface or a short way away from the beach”

it is a myth that the water in summer is “very cold” or “freezing”. The top layer in the lakes will warm up from spring into summer, reaching at least 22° in hot weather, and that layer can be deep especially in a large lake. Swimmers will be in the top layer of 1m or less, and in summer that will vary less than in autumn. https://www.imogensriverswims.co.uk/blog/are-lakes-freezing-cold-even-in-summer-including-quarries-reservoirs/ . It is not true that the water suddenly gets colder away from the beach, nor that it cools dramatically overnight in summer.

Swimmers should be aware of water temperatures, and if not used to water cooler than a heated swimming pool should stay within reach of the shore and not get too cold.

“Cramp, caused by cold or pockets of cold”

Cramp can be an issue causing panic and hampering swimming ability. Not generally caused by cold, nor by eating before swimming, but by dehydration or excessive strain placed on leg muscles. Panic is the greatest risk from cramp, and that could lead to drowning, but can be mitigated.

Prevent by being well hydrated and warming up your muscles before a swim, swim in a relaxed way, build up your swimming techniques and the time you can stay in the water before going far from shore. If it happens when you are in deep water, relax and float on your back, massage the area if possible, or wait until it has passed.

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“Swimmers should wear wetsuits for buoyancy and warmth and to prevent cold water shock”

Wetsuits do not prevent cold water shock, in fact can make it more of an issue if people do not allow some cold water in to the suit before swimming off. Experiencing cold water shock when away from the shore can be a serious risk. Wetsuits could delay the impact of cold, in particular swim failure, however do not prevent it completely so it is important to be fully aware of this risk.

Swimmers do not need additional buoyancy, and in fact it can interfere with a good swimming stroke. Buoyancy can be a benefit, if someone has stayed in too long and is far from shore and experiences swim failure, however prevention is a better way to avoid this risk. Many swimmers choose not to wear wetsuits at any time of the year – though some choose to wear them or other neoprene clothing for part of the year – and find that they prefer to be able to get dressed quickly after their swim. Every swimmer is different in their tolerance of cold, and in their level of acclimatisation. If you feel you need extra buoyancy, wear a buoyancy aid, but also be aware of your swim capability and don’t go beyond it. If you wish to wear a wetsuit, then do so, but if you don’t, then don’t. Be aware of the differences and issues related to each. It is colder to swim without, so you need to be very aware of your own body’s response to cold, but it is also quicker and easier to get dressed and warm afterwards. Wetsuits can cause overheating in warm water and warm weather, and are generally advised against in such conditions, as overheating is a serious risk.

If you wear a wetsuit, make sure you allow some water into it before moving off to swim, to avoid cold shock when further out into the lake. Take it off quickly along with any other wet swimwear so that you can get dry and warm quickly afterwards. Be aware of all the risks of cold, which can affect wetsuit wearers, even if the effect is delayed. Be aware of the risk of overheating in hot weather and warm water in summer.

“Swimmers should use tow floats for safety”

Tow floats are not safety devices. They have two purposes. One is to make swimmers visible, which is important when there are boats or other water users you could come into conflict with. The other is to carry things, such as valuables, phones, some clothing. They are not buoyancy or safety devices, and relying on them as such is not a good idea, especially out in a lake, where swim failure if you get too cold hanging about could be an issue. And cheap or worn tow floats can burst, so should not be relied on. There is one other potential purpose for a tow float – finding someone who has drowned, however it is better to understand and follow safety information to prevent this happening. www.outdoorswimmingsociety.com/tow-float-or-not-tow-float/

Consider using tow floats where there are boats, especially powered boats. They are not generally needed in other conditions, and can pose a serious risk in choppy waves, in flowing rivers especially if there are branches or other obstructions they can get caught on, or if swimming close to others, such as in a race. Never rely on them as a safety device; only swim within your capability, and if you are getting cold it’s better to swim back to shore quickly rather than hanging about.

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“The water is too acidic to be safe to swim in”

The water in this lake is relatively acidic, pH 4.5. Formal swim venues are advised to avoid water below pH 6, however more detailed research shows that there are no issues down to pH 4 (incidentally the same pH as drinking water in parts of the USA). Rainwater has a pH of about 5, and in these lakes there is no limestone to change that level, then in addition the pyrite which is present in these soils reacts with oxygen and water to create very dilute sulphuric acid to lower it further (information provided by expert geologist and hydrogeologist). Slight risk of skin irritation, especially eyes. No issues reported by swimmers. Read more, www.fondriest.com/environmental-measurements/parameters/water-quality/pH/

Be aware if putting face in the water, especially if skin is sensitive. Unlikely to be an issue for most people.


Angling litter, especially hooks and lines

Unfortunately, when there is angling, especially if there are trees or branches, hooks and lines can get caught and left behind, which can be a risk of injury if you stand on them or catch yourself on them. Angling has been introduced in the Brickyard Lake, but is unlikely to take off in the Great Lake because  the pH levels mean that there will be very few fish.

Wear swim shoes, watch out for litter.

Blue-green algae

Observed 22 October 2023: a small amount of blue-green algae on the western edge of the Brickyard Lake. Very unlikely to occur in the Great Lake because of the pH levels. The risk to humans is minimal when there is only a small amount blown onto the edge by the prevailing wind. Avoid swimming in a thick bloom of algae, which can cause skin irritation and sickness if swallowed.

Look out for it, avoid swimming where there is a thick bloom, but if the amount is minimal and on the edge, it should be possible to swim in the lake, perhaps keeping your head out of the water and avoiding swallowing any.

Jet skiing, windsurfing, and other water sports

Other water users can be a risk to swimmers, especially if they don’t see them or can’t avoid them. Unpowered boats are less of an issue, but can still pose a risk.

Be visible or steer clear of powered boating areas.

Jumping into the water

Jumping into water can be a risk – jumping into water that is too shallow, jumping from a height without knowing how to do so, hitting obstructions or other people – all can cause injury. Jumping straight into water without getting used to the temperature first can cause cold water shock, especially if you go through the warmer layers into the deeper colder water below, and this can mean the involuntary gasp can bring water into your lungs.

There is nowhere suitable on either lake for jumping into the water (this information comes from very experienced height jumpers). If jumping somewhere else, be sure to check for obstructions, check the depth, know how to do it, and get used to the water temperature first.

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“Machinery, old gantries, old railway and other large structures in the water, left when quarry closed”

Although theoretically these still could be there, at the bottom of the lake (5 m or more deep), sonar investigations have not found any sign of them, and they don’t show up in drone photos and footage at a level that could affect swimmers. Swimmers would be in the top metre of water.

No specific action to avoid these is needed for swimmers, but they should be vigilant. Jumping not a good idea.

“Barrels of noxious chemicals thrown in to the water when the quarry closed”

Not clear what sort of chemicals might have been used in a silica sand quarry, and it is very unlikely that this would have an impact especially on a large lake as any such material would be much diluted.

No action needed.

“Ironwork and spikes, opposite Bawsey Bay”

Sonar investigation found no evidence, other than branches from the adjacent woodland, however low water in 2022 revealed a few pieces of metal, some jagged, at the beach near the West car park. As the water is very clear these should be visible.  

Take care if swimming near the woodland edge, look out for branches or other obstructions. Look carefully before getting in, wear swim shoes, and take care. Don’t jump in from the side of the lake.

“A pipe that sucks water and will drag swimmers under”

No evidence of a pipe, even when this and adjacent quarry were working – documents showed that was not the case. There is certainly no such pipe operational now.

No action needed. Swimmers should be aware of swim failure/cold incapacitation.

“Weeds that will drag swimmers under or trap them”

Very few if any weeds in Great Lake, and certainly not anywhere near the beaches, due to the pH level. Very few weeds in the Brickyard Lake, either. Weeds do not drag swimmers under in any circumstances. Where they are present, they can potentially trap people who jump or dive into them, and they can entangle people, generally in rivers or when doing a circular stroke.

No action needed. If swimming where there are weeds, best not to jump or dive into them, and be aware of what to do if you panic. If tangled in weeds, avoid circular swim strokes or reverse the direction.

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The landowner does not wish you to swim, and you should obey signs, rules, and their policy”

The landowners’ policy to say ‘Stay Out’ of the water is an approach that cannot work and doesn’t help water safety. It is impossible in practice to stop people swimming: people want to swim and paddle in the water especially in summer, and many have either done so all their lives or more recently discovered how enjoyable this is and how much it benefits them. We need more places, especially suitable ones, so that people can experience outdoor swimming and learn how to be safe. A prohibition approach not only doesn’t work, it can be counter-productive and encourage riskier behaviour and reduce respect, especially if based on inaccurate information. For example telling people that the water is freezing in summer when it’s well over 20° reduces credibility and goes against people’s real experience and common sense. The approach prevents basic essential safety information getting across to people, and having that knowledge is the best way that people can keep themselves safe. It is better to base policies on the latest research and up-to-date understanding of water safety and behaviour, as do the national safety organisations and many landowners and authorities.

“The landowner will have risk assessed the lakes”

It is not clear whether they have risk assessed as they have provided no information on this. Some of their pronouncements about the risks are inaccurate, which suggests that if they have done a risk assessment it might not be accurate or detailed enough in relation to swimming and paddling your feet. A landowner does have a duty to risk assess water when they know or suspect people might be swimming, and when there is a risk of people falling in, and they must warn of any unusual risks that can’t be seen. They do not have to warn of the usual risks of swimming such as cold or deep water, though if they do they should do so accurately.  

“If people swim in Bawsey Lakes the owner will close the whole park to the public”

This is unlikely, as the agreement under which they took it on required them to keep it open to the public, and the revenue from parking, the café, and events helps pay for its maintenance. There are public footpaths and byways crossing and skirting the park, which are protected in law from being closed.

“Swimmers choosing to swim in these lakes will be responsible for other people copying them and then drowning”

Every person takes responsibility for their own actions, and that is reflected in established case law on swimming and liability. The claim makes an assumption that people will drown if they swim in these lakes, which is answered in other points – drowning when swimming is very low risk, when taking account of the millions of people who do it safely every year – and these lakes have far fewer risks than many other water bodies, especially the sea and rivers. It assumes that people are too stupid and lacking in knowledge to keep themselves safe, which is far from the case. It is true that people have been denied accurate information and that this is unhelpful in keeping them safe, and these kinds of statements along with Stay Out policies make it much more difficult for people to get information and to get used to swimming outdoors.

We need far more places, especially benign and relatively safe inland water, for people to swim, to learn how to swim safely outdoors, and we need policies based on evidence, not emotive and ill informed statements.

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“Swimming at these lakes is insensitive as people have died here in the past.”

We feel strongly that further tragedies must be prevented, and believe that could be done more effectively by taking a different approach. We seek to raise our points in as respectful a way as possible and to recognise that people have died at the lakes over the past 10 years, and we do not in any way wish to belittle people’s concerns. However, most of those concerns are based on misunderstandings and inaccurate information about the risks at the lakes and about outdoor swimming generally. Outdoor swimming is not dangerous, in fact is very low risk and even more so when the level of knowledge across communities is raised so that they can stay safe.

Sometimes the approach to outdoor swimming appears to be very different to other risks in society. For example we might consider whether it is appropriate to cycle in a place where someone has been killed when cycling, and some might decide that they feel those roads are not safe to cycle along, but we are not generally told that it is insensitive to cycle or that we should not cycle along those roads. Instead we educate drivers to be aware of cyclists and educate cyclists to be aware of the risks and how to stay safe. The relative risk of activities can be seen in a table from RoSPA in this OSS article about drowning statistics.

“The lakes are dangerous because people have died in them over the last decade”

Lakes, like any other water body, have certain risks, but these can all be mitigated, and in fact lakes have far fewer risks than water bodies such as the sea and rivers. People have died in lakes because they were not aware of key safety information or were not able to swim. They died of causes probably related to cold or swim capability – cold water shock, swim failure, swimming when not capable enough to do that swim, falling off an inflatable, trying to rescue a drowning person, or of cardiac arrest which might or might not have been related to cold. It is utterly tragic that people have died in ways that could be prevented by giving them accurate information. Focusing on trying to keep people out of open water instead will do nothing to keep them safe.

Crucial to avoiding such tragedies and to keeping people safe is giving them key water safety information: avoid cold water shock by getting in gradually and not falling in; know what to do if you fall in or panic – Float To Live; avoid getting too cold and stay close to shore unless experienced in cool water; swim within your capabilities; keep an eye on children and vulnerable people; do not get into the water to rescue anyone in trouble, instead call for help, tell them to float, throw something that floats.

“Swimmers should go to the sea, to rivers and to swimming pools instead of these lakes”

The sea and rivers have a range of risks that are not present in a still inland lake, and have a much higher number of drowning deaths (though still very low risk). Additional travel adds risk, as well as being bad for the environment. Swimming pools give an entirely different experience, as well as requiring travel. Lakes have far fewer risks than other water bodies, with no currents, waves or tides. This article examines the relative risks, https://openwaterwheway.wordpress.com/2021/06/29/sea-or-reservoir-which-one-might-be-safer/

If swimming in the sea or in rivers or in lakes, be aware of the specific risk factors to these types of water bodies, and of the specific water body, and of information that can make sure you keep yourself safe whichever water you swim in. Much information is available, including here, www.outdoorswimmingsociety.com/category/survive/  

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“Outdoor swimming is dangerous”

Outdoor swimming has risks, but these can be mitigated. Outdoor swimming poses a very low risk of drowning, and considerably lower risk than many other activities in life (cycling, driving), and on water (motorboating, jet skiing, angling, canoeing, sailing). www.outdoorswimmingsociety.com/drowning-statistics/ The inaccurate and misleading impression that outdoor swimming is dangerous prevents useful information being given so that people can stay safe, and takes no account of the enormous benefits of this healthy outdoor activity. Giving people false information, for example that the water is freezing, when they can feel for themselves that it is not and in fact is very warm in summer, destroys any credibility and means that they are less likely to believe any genuine safety messaging.

There are a small number of tips that can keep people safe from the main risks from outdoor swimming, and the focus should be on making sure people know these so that they can keep themselves safe. Key tips,  www.imogensriverswims.co.uk/blog/issues/swim-play-in-water-safely-q-a/ ; and www.outdoorswimmingsociety.com/summer-safety/    

“People should stay out of all open water, no matter how tempting or enjoyable it is to swim”

Saying Stay Out of open water does not work, does not keep people safe, and behavioural science tells us actually makes them more likely to behave in a risky manner. It is unfortunate that some local safety organisations and landowners are not aware of the latest policies based on research and statistics.

Giving accurate and constructive information is a much more effective way to keep people safe, and is the approach taken by the National Water Safety Forum, based on latest research and statistics, representing all key safety organisations.

shallow sandy edge of large lake, reflecting blue sky

Looking east from the west beach of the Great Lake

You can also download this page as a document (Word.docx 9 pages)

Please note: all swims and paddles are always at our own risk. Including a location on this website does not indicate that it is recommended or that it is safe; each must do their own risk assessment each time they swim or travel to a location. Please be aware that the level of risk can change over time, depending on a range of variables such as temperature, weather, time of day or night, personal fitness, and level of fatigue – and so each of these variables will need to be considered by an individual before making their own personal decision on whether to swim, where to swim, and for how long. There is Swim Safety info on this website, and on Outdoor Swimming Society website, Survive section. Please follow the Outdoor Swimmers Code. I accept no liability for the choices that people make. This website is not produced by an organisation, commercial or otherwise, and I am not assuming any legal responsibility for those who read the website, and to the maximum extent permissible by law I exclude all liability in the event of injury or other loss.

Location details for Bawsey Pits or Lakes 

swims and swim places, and related issues