boats on the River Crane

Those of us who live along the banks of the tidal River Crane in north St Margarets love our river. We build decking and jetties alongside it, our children paddle in it, we delight in the wildlife that lives along its banks. We keep small boats on it and every year in the summer we gather as a community to clean it out. We enjoy our river, and yet…

…when exceptionally heavy rain is forecast or high tides expected we begin to worry. We worry about the weight of the water racing down to the Thames and we worry about the incoming tide that is waiting to meet it. We worry about the 4 or 5 times a year when the river overflows into our gardens and covers our lawns with a thick layer of silt, plastic rubbish and grass clippings. Most of all – and even though it hasn’t happened in living memory – we worry about the possibility of our houses being flooded.


Boats on the River Crane

On Friday, at the end of the BBC 10.00 o’clock News the London weather forecaster gloomily warns ‘exceptionally heavy rain – up to 50mm – and a very high spring tide might cause some local flooding’. The national weather forecaster who follows says the same. ‘The exceptionally heavy rain in the South East combined with high spring tides might result in flooding.’ Up and down the tidal Crane and out along the Thames and its many tidal tributaries, people put down their cocoa and look at each other. ‘Exceptionally heavy rain AND an unusually high tide? Mmmmm.’


Just before 1.00pm on Saturday afternoon the tide, listed as a healthy 6.88 metres, starts to come in, slowly at first but then with enough force to stop and then reverse the flow of the water. The Crane is already swollen to the top of its banks with the heavy rain that has fallen and there is nowhere for all this water to go – apart from sideways. By 1.30pm half of my garden is under water. At 1.43pm the tide stops and then turns. By 2.30pm the garden is clear but covered in mud.

The next tide, (6.08 metres) is at 2.12am on Sunday morning. Maybe it is anxiety or maybe I just need to go to the loo but at 2.15am I am up and looking out of the window. Once again the garden has disappeared under water, which is now within 4 metres of the back door. I immediately start thinking about how I might flood proof the kitchen – lift the fridge and the freezer off the ground perhaps or move the cat to a higher room? I check my insurance. Are we covered?


The next tide, at 2.36pm on Sunday afternoon, is expected to be even higher. If anything is going to turn my house into Swan Lake this is it. At 2.00pm I put on my wellies and go down the garden through the muck to see what the river is doing. It has fallen slightly but it is still swollen and volatile. All it will take to set it off is the 7.18 metre incoming tide making its way up from Kew. I wait for the first signs; for the Crane to stop flowing and then reverse – but nothing happens. At 2.36pm, when the tide should have been at its peak and my garden lost under water, the River Crane continues its frantic flow towards the Thames but holding its height and staying within its banks. Someone somewhere has turned the tide off, like a tap. Someone somewhere has saved us from flooding.

On the BBC London News at 10.25pm that evening the newsreader announces that the Thames Barrier has been raised to prevent flooding in the London area. At Woolwich, 20 miles from St Margarets, huge metal gates have been rotated up from the river bed and are now holding back the tide. The newsreader says the Thames Barrier will stay in the raised position until 4.00am the following morning to keep back the next tide.


It worked. Monday morning. The Crane is still flowing vigorously but it is comfortably within its banks and the level is still dropping. The sky is clear blue and I am comforted by the thought that the silt covering my lawn might do it some good.

3.25pm. A tide of 7.6 metres is expected but once again it does not materialise. The Barrier is still holding back the water that threatens to swamp London. All along the Thames from Teddington Lock to Greenwich hundreds of thousands of people who live by the river, or along its many tributaries, breathe a sigh of relief. The highest tide of the current spate (7.42m) is tomorrow afternoon but once that is out of the way the tides will start to fall back to a more respectable 5.36m. North St Margarets will be home – and dry – again.

The tidal crane, which runs from the Thames at Thistelworth Marina to the A316, marks the northern boundary between Richmond and Hounslow. 99.99% of the time its runs peacefully down to the Thames. Ever so often, maybe 4 or 5 times a year, at a particularly high tide or after exceptionally heavy rainfall it might break its banks and come into our gardens but flooding? No way! We’ve got the Thames Barrier looking after us.

“It is very nice to have a river at the bottom of your garden.
It is not very nice to have your garden at the bottom of the river.”



The Thames Barrier is one of the largest movable flood barriers in the world. It protects 125 square kilometres of central London from tidal surges. That’s 1.25 million people, historic buildings, offices, power supplies, tube lines, hospitals and more. The Environment Agency runs and maintains the Thames Barrier as well as the capital’s other flood defences. These defences include floodgates like the Barking Barrier and raised riverbanks.

The Thames Barrier is one of London’s most striking and famous landmarks. With its distinctive stainless steel piers it spans 520 metres across the Thames near Woolwich. The barrier, which became operational in 1982, has 10 steel gates that can be raised into position across the River Thames if a tidal surge is predicted. When raised, the main gates stand as high as a five-storey building and as wide as the opening of Tower Bridge. Each main gate weighs 3,300 tonnes.

— from Martyn Day