The Tide Sets Your Day, Not the Weather

A bright and still morning can be the most deceptive weather of all for a coastal walk. A forecast tells you whether you will get wet from above. A tide table tells you whether you will get wet from below, and on a flat, channelled estuary that second answer matters far more. On a spring low water, a wide sandy estuary can expose a kilometre or more of ground. Within a few hours, most of it is gone.

The water rarely arrives as a neat wall. It fills the channels first, quietly and from the seaward end, so the route that brought you out can be cut behind you while you are still busy looking at something else. This is how experienced local people get caught, not just visitors, and it is why tide tables are worth reading before you decide where to go rather than after.

Reading a Tide Table Properly

Most harbours, piers and estuary mouths publish their own table, and the differences between them are real. A few things to look for:

• Times in local time. Check whether the table uses GMT or BST. A single hour out can put you on the wrong side of a channel.
• Heights, not just high and low. A 4.2 metre high water is a very different proposition from a 3.1 metre one at the same spot.
• Springs and neaps. Around the full and new moon, tides are bigger and low water drains further. Around the quarter moons the range drops, often to roughly half. A walk that is comfortable at neaps can be a wade at springs.
• Local quirks. Some places have a long stand of tide or a double high water, so the familiar six-hour rhythm does not hold. Read the harbour notes or ask, rather than assuming.
• The rule of twelfths. The tide rises roughly 1/12 of its range in the first hour, 2/12 in the second, 3/12 in the third and fourth, then 2/12 and 1/12. The third and fourth hours are when everything changes fastest.

Estuary Channels and Ground That Moves

Estuary ground is not fixed. A winter of fresh water can shift a channel ten metres sideways, deepen a pool, or build a new bank where there was mud last year. Sand and mud that looks firm can be soft underneath, and the edges of channels are often steeper and slipperier than they appear from twenty paces away.

Wear something with grip rather than tall wellingtons, which fill and drag. Cross channels only where you can see the bottom and the far side. If in doubt, turn back early rather than push on and hope, because the return leg is the one the tide has spent the whole day preparing for.

Five Minutes That Buy You Hours

• Check the tide table and the inshore waters forecast on the morning itself, not the night before.
• Plan to be off exposed ground two hours either side of low water, not at low water.
• Tell someone your route and your expected return, because signal in an estuary is patchy at best.
• Note a landmark that will still be above water at high tide, so you know what there is left to stand on.
• Keep dogs close near channels. They are quicker than you and cannot read a table.
• Carry a phone in a dry bag, water and a spare layer. On wide flat ground, wind and wet take heat out of you quickly.

Nature and History on the Tidal Edge

The tidal edge is among the richest habitat in the country: saltmarsh, glasswort and mud that feeds curlew, dunlin, oystercatchers, shelduck and wigeon. High water is when wading birds crowd onto the last dry ground to roost, so give roosts a wide berth and let the high tide be theirs. Walk the low-water hours instead, when the birds are spread out across the flats and feeding.

People have read these tides for centuries. Salt pans, oyster beds, ferry crossings, causeways and drowned ports all sit along the same lines. If a footpath runs oddly straight, or a lane ends at the water with a name like Ferry, the tide was there first, and the crossing came long before the road.

Eating Well From the Estuary

Mussels, oysters, cockles, clams, samphire and sea bass come out of these waters, and a harbour stall or local fishmonger will beat anything shipped in. If you gather your own, gather carefully. Check local byelaws for seasons, size limits and permitted areas. Avoid shellfish for a few days after heavy rain, when overflow can wash in. Keep only shellfish that are alive and tightly closed, and cook them thoroughly. Never eat anything you cannot identify with complete certainty, and leave the roots of samphire and the undersized shellfish behind so next year's harvest is still there.

Take the tops of samphire from late June, when it is crisp and salty, and eat it within a day, steamed for two minutes with butter. It tastes of the marsh it grew in, which is the whole point of walking out to find it.