Holy Island Causeway: why tide time barriers are a daft idea

18 Aug

Holy Island Causeway: why tide time barriers are a daft idea

I wrote this post because I grew tired of explaining this every time, and thought it would be helpful to the people who genuinely want to know why tide time barriers either side of the causeway to Holy Island (Lindisfarne) are objected to by locals and are genuinely a bad idea. I’ll also suggest another option at the end, but that’s just my own thinking.

The Causeway and Tides

For those who don’t know, the Holy Island of Lindisfarne in Northumberland is connected to the mainland by a causeway road that gets covered by the North Sea twice a day when the tide comes in.

The Council issues safe crossing timetables, which you can check to tell you when it is safe to cross, and when it isn’t. These are available online, and are posted either side of the causeway.

As of late 2019 there were also large electronic signs letting people know what the safe crossing times are for the day, which seemed to help, but the council did not manage to keep them showing the correct dates, and after a few occasions when they showed wrong crossing times (including one occasion when they caused drivers to follow them blindly and drive into the sea), the council gave up, and now they are only showing a general warning to check tide times.

The ignorant, ill informed and unlucky

Despite these measures, every year some motorists ignore the advertised safe crossing times – not realising how quickly the North Sea rises on the flat surface on which the causeway road lies – and thus they get trapped by the rising tide and their car submerged.

Some of these people are genuinely ignorant, simply not aware of the causeway and somehow they miss the (large prominent) warning signs.

Others are stupid idiots ill-informed, and think that if they can’t see water on the road when they set out, they’ll be fine, even if the council’s official safe crossing time has passed.

And sometimes there are honest mistakes by those who have misread the tide times. It happens even to people who aren’t stupid. It’s just a fact of life.

The sequence of things usually runs like this: a car gets caught out by the tides on the causeway. The (amazing) Coastguard crew and RNLI get called out to save the occupants of the car. The event gets coverage in the media, and then (the usually justified) outrage ensues on Twitter and Facebook, about the irresponsible numpties who put themselves and others at risk by not checking tide times or risking crossing the causeway when they shouldn’t.

Causeway barriers and why they are not a good solution

One of the more common responses (after: “string them up” and “make them pay”) is a legitimate question: why does the council not simply erect barriers that would block access to the causeway during the official unsafe crossing times?

To explain why this is a daft idea, we need to start with an important statement: the North Sea does not obey the tide times published by the council. People don’t realise that these are predictions based on tide heights and several additional factors, but they are not definitive and therefore have to be very conservative. The official safe crossing times are very helpful to ensure tourists only cross within the predicted times, and usually do a good job of telling you when you can definitely cross (with some rare exceptions during stormy weather and fast tides), but they do not tell the whole story.

What the locals know and the tourists don’t is that by checking the height of a certain tide, weather conditions and local landmarks, they can know with certainty if it is safe to cross outside of the published tide times, especially during falling tides. And these aren’t a mere few minutes. For example, on a receding tide I can sometimes look at landmarks out of my window and know that it is safe to cross the causeway a full 90 minutes or more before the council’s official times. On some summer days, the council’s times say the causeway would be closed for four hours, when in fact the road is only impassable for half an hour or even less.

Locals who return from work on the mainland can tell by the height of the water near the South Low river estuary whether they can cross or not, regardless of the official times.

I have worked off-island myself, and my commute would have been punishing and probably untenable if I had to adhere only to the official crossing times. In fact, I would have been unlikely to keep that job. Imagine coming back from a long commute from Edinburgh, arriving at 8pm to a barrier that will be closed until 10pm, even though you know for certain that it is safe to cross there and then.

There were also occasions when, in an emergency, it was possible to evacuate a casualty using a high-framed vehicle, and get them to a waiting ambulance, rather than have to try and transport them by sea (not always feasible) or wait for a helicopter that might take 45-60 minutes to get here.

If you consider a community that is dependant on this road to go to and from work, to get groceries, to leave or arrive – and then barriers are put in place that block them from leaving or getting home at times they know for sure are safe, just because of a few daft tourists every year – this is not only unjustified but grossly disproportionate.

The village on Holy Island is not a theme park. It is a working community of people, with some families that have lived here for generations. Severely shortening the times they can cross to the mainland would be onerous, unfair and unjustified.

Four other issues with barriers that people often overlook

  1. When the council tried to put in place large signs that show the tide times for the specific day, they failed to keep them showing the correct times, and on several occasions the tides feed displayed the wrong times. As mentioned above, this actually caused one vehicle to follow the incorrect times and require an RNLI rescue. Now, imagine if the council had to do the same with barriers. This isn’t like the mature technology tracking a train’s arrival at a level crossing using sensors. It’s reliant on an accurate use of feed technology, which evidence shows doesn’t always work, with potentially dangerous results.
  2. After you leave the Island’s car park and drive along the causeway, there is a turning to two lone houses (Snook House and Snook Tower). During the highest tides they become inaccessible, but during lower tides it is still possible to reach them. If there were to be a barrier on the Island side, it would mean access to these two properties would also be impossible at times when driving there is entirely safe.
  3. If a car parks somewhere between either ends and wants to return to the island or mainland, but then the barriers are closed, that car will be stuck and may become submerged (I realise that you can create barriers that allow cars to sidestep them, but then doesn’t that take us back to the same starting point: daft drivers who ignore warnings?).
  4. If you come to blindly rely on the barriers without using common sense, you risk people assuming that an open barrier means you can always cross safely. Though not common, there are occasions when the tide rises more quickly than predicted, and the causeway becomes impassable earlier than the official times.

A possible alternative

Modern technology may hold the key to a solution that does not curtail the lives of locals and at the same time makes crossing the causeway more safe. If ever there was a budget for this, perhaps the solution would be to place measurement poles with connected sensors at specific points in the sands between the Island and mainland. These would measure the exact height of the tide and transmit data to a central point, which would then be able to calculate exactly when it is safe to cross, in real time.

The information would be used to operate traffic lights either end of the causeway, green when it is safe to cross, turning amber a certain number of minutes before the road is entirely impassable and then red to indicate that it is definitely unsafe to cross.

Reliable connected sensors would mean we know for sure, rather than rely on local knowledge, guesswork or folly. Then again, some might argue that they would remove a lot of the mystique and romanticism of the place, and that the few rescues on the causeway every year must be seen in the context of about 750,000+ annual visitors.

Update (6 Nov 2020): I’ve found out (thank you, Andrew) that apparently this solution was proposed before, and even received media coverage back in 2007, but has not been taken any further at the time. Hopefully, with the advance of technology, this is more viable (and less costly) these days.

Finally, and to be clear: although there have not been deaths on the causeway in recent memory and the average of 10 annual cars rescued every year is a tiny proportion of the 750,000+ annual visitors to Holy Island, every life at risk is important, and the community here also cares deeply about the safety of Coastguard and RNLI crews.

However, for the reasons explained, barriers are not the solution, and would impose what are effectively unnecessary curfews on an entire community.

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