The surprising complications of tide-watching

cover

Hugh Aldersey-Williams’ “Tide: The Science and Lore of the Greatest Force on Earth” has a title that sounds hyperbolic, but is endearing in its combination of a certain rhetorical restraint (noted by the Guardian reviewer linked to above), simple awe and a willingness to get into quotidian detail. I went into the book thinking that the tide basically boiled down to the influence of the moon – there is a lot more to it than that.

Early on, Aldersey-Williams decides he needs to observe an entire tidal cycle. This sounds something very straightforward – just sitting by the sea for a day! – but not so:

It is an odd idea, I admit, simply to sit and watch the water for twelve or thirteen unbroken hours. You might find similes coming to mind to do with watching paint dry or grass grow. But I will shut these unhelpful analogies out of my mind. I do not know what I might see, but I will at least try to note down anything I do. I do not know what I might see, and that will be the best of it. The first requirement was to select a site where I could do this. Every part of the British coast is subject to substantial tidal movement. I live in Norfolk, a county that bulges obscenely out into the North Sea (in old satirical cartoons that depict Britain as a person, Norfolk is always the rump). The coast is correspondingly distended, and so I was spoiled for choice. I considered Blakeney Quay. I’d seen the tide running in there so fast round the bend in the river – I reckoned its speed as about three metres per second, based on counting as pieces of seaweed hurried by – that it sent thick wooden mooring posts into frenzied vibrations. But the place was too overrun with tourists, and I could see that I would be constantly interrupted by curious busybodies. Instead, I selected a site a mile or two away where I knew I would be undisturbed

Aldersey-Williams has even more criteria:

The scene would be nothing like the domesticated sublime of the beach at Lyme Regis that Jane Austen describes in Persuasion, ‘where fragments of low rock among the sands make it the happiest spot for watching the tide’. My prospect would be more like that in George Crabbe’s epic poem of East Anglian life, The Borough. I would ‘view the lazy tide / In its hot slimy channel slowly glide’. I would make myself into what Charles Dickens in Our Mutual Friend called one of ‘those amphibious human-creatures who appear to have some mysterious power of extracting a subsistence out of tidal water by looking at it’. Reading passages such as these, I saw that writers use the tide as a kind of hypnotist’s watch. It is something to induce a state of reverie or, more dangerously, a trance. I would have to be careful not to fall into daydreaming if I was going to make more incisive observations of the unceasing rise and fall of the seas. Next, I had to choose a suitable time of year and time of day to make my study. The tides are in constant action, washing the world’s shores, but they vary according to astronomical factors that are subject in turn to their own complex temporal rhythms. I did not want to freeze or fry out on the marshes, but more important than that, I would need my thirteen hours to fall during daylight in order to make my observations. Wherever you are, a full tidal cycle, from high water back to high water (or low to low), takes nearly this length of time. This constraint limited me to the months from March to September when the days were long enough. I also wanted to observe a fairly typical tide, not a huge one that would flush me out of my vantage point when high water approached, nor one so meagre that I would miss the things I should normally expect to see

….

Any thirteen-hour time slot guaranteed that I would see one high water, one low
water, one full flood tide and one ebb. But where in the cycle did I want to start my work? This was more a matter of aesthetic preference and narrative design. To begin with the tide in full spate, either flooding or ebbing, seemed to me melodramatic. An obscure logic told me that low water would be a natural beginning: a bath or a bucket starts empty, after all, and its story is to be filled. This version would give the greatest sense of a flooding. I could watch the flood tide fill the creeks, but I would then have to see them empty again as the cycle came around, and something about this displeased me. Or, I could start at high water. But this was not right either: even though I would then end on a high, it seemed wrong to begin by witnessing the departure of the substance of my tale. I feared that the immediate ebb might be the end of my own story. In the event, I found my choice still more restricted. The tide table showed few days when the tidal range would be sufficient for my needs, the day long enough, the weather likely to be bearable, and the place quiet enough – a weekday during school term rather than a weekend – that I would not be disturbed. In the end, I chose a day when the sun would be rising just as the ebb was gathering pace. I would begin my observations about an hour after high water. The mood should be one of calm and expectation. My morning would see the tide recede and the muddy shore revealed. High water would come late in the day, and provide a well-timed climax. By starting an hour or so after high water, I would then stay on through the subsequent high water long enough to see the ebb begin again. This, I felt, would show more truthfully that the tidal cycle does not in any way peak or culminate at high water, as we might be tempted to think, but that it goes on in an eternal cycle in which no momentary state has any more claim to special status than another

Aldersey-Williams prepares himself for longeurs:

Though I intended to be diligent in my observations, I imagined there might be long stretches when little was happening, and so I armed myself also with a copy of The Oxford Book of the Sea. It held excerpts of many works I would need to familiarize myself with, from Rachel Carson’s The Sea Around Us to Matthew Arnold’s allegorical poem ‘Dover Beach’. These poems and prose pieces would remind me of the main to which my insignificant creek, thanks to the tide, was eternally connected and intermingled.

I don’t want to spoil the account of his actual tide watch, which is well worth reading, but can reveal he does find not much time for reading:

I had thought that there would be longueurs in my day. But it is clear now that I will be kept very busy. I find it necessary to carefully plan my activity between each hourly tide reading, because I know I’ll only have the chance to do certain things – like delving in the mud for worms, or observing how the wind whips up waves – at certain states of the tide. Suddenly, my schedule starts to look like a school timetable. I have the whole curriculum covered: plotting water level graphs (mathematics); observing mud life and marsh plants (biology); recording water flow (physics); canoeing (PE); contemplating the cosmic order of things (religious studies?). I will be so busy for the day that English will have to be cancelled; The Oxford Book of the Sea lies unregarded, its pages turning crisp in the dry breeze.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s