Where Does The Thames Stop Being Tidal?

It may be perhaps surprising to know but a large portion of the River Thames is actually tidal, and hence subject to tides. Of the Thames’ 346km (215 mi) total length, 160km (99 mi) is in fact tidal, that’s close to half of the length. This section, which is known as the Tideway, stretches all the way from the sea until stopping at the first lock on the river in Teddington. The Tideway includes Thames Estuary, the Thames Gateway and the Pool of London.

During the course of the year the tide rises and falls twice a day by up to 7m (24ft). As the river also has to expel fresh water from a large part of England it takes longer to subside (or ebb, to use the correct parlance) (taking 6-9 hours) than it does to flow in (which takes 4-5 hours).

What Does the Thames Barrier Do?

Considering the Thames goes through the heart of London and 7m seems like quite a big rise you would be right in thinking that this could cause a problem. The truth is, it would, if the city hadn’t built the Thames Barrier. Built in 1982 in Woolwich on the Eastern side of the capital, the Thames Barrier (which you can see at the top of this post) was built to protect central London from any flooding as a result of tidal surges.

The barrier works by shutting during periods of high water in the river during an incoming high tide, stopping the section of the Thames after the barrier from rising. Once the tide turns it then opens and lets the water ebb once the levels of the water equalise on both sides of the barrier. Pretty clever eh?

Until recently the barrier wasn’t used too often, only being used 150 times since it was built some 30 years ago. However, recently it has been in operation much more. Between December 2013 and Feburary 2014 it was closed 28 times due to record amounts of rainfall.

It’s a good job it’s there, as otherwise this is how the Thames would look (according to the Environment Agency) after a tidal surge, or after a period of tidal surges partnered with excessive rainfall:


That’s right, the Thames Barrier protects Tower Bridge, The Houses of Parliament, the O2 arena and areas including Whitechapel, Southwark, the Isle of Dogs and West Ham that would have been at risk of flooding.

How Does The Thames Tide Affect Me?

In truth you’re unlikely to notice the effect of the tide on the Thames. One noticeable difference will be that at low tide you will be able to access some of the Thames’ riverside, which some people make the most out of by beachcombing for lost treasures or seeing some parts of London that you rarely glimpse, such as these underwater horse sculptures which are only visible for a few hours each day, before heading back underwater.

For us the tide has some effect on our boats, meaning that cruising with the flow of the tide we can travel faster, while against the tide the reverse is true. However, you can be sure that if you go on one of our river cruises, party boats or corporate events the direction of the tide will be far from your thoughts.

And we have one last good tidal fact for you, an instance when the low tide came in very useful. When one of the last few Concorde’s had to be moved from Hammersmith to Scotland it was carried on a barge that was only able to fit under the bridges because it navigated down the river on low tide. Another interesting Thames fact for you! (…and we have plenty more).

If you would like to hire a boat from Thames Leisure and see what life is like on the river then see our Instant Quote Calculator to find out how much it might cost or simply get in touch with us directly. We’re always happy to help.

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