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| Britain is a little short on natural
wonders but we have one right here beside us which can be seen several times each month:
the Severn bore. The bore is a surge wave which forms in the funnel-shaped Severn estuary and travels upstream as a sequence of three or four unbroken waves. It splits in two at Lower Parting, swamps the weirs at Maisemore and Llanthony, and if it is a really big one, may reach as far upstream as the Diglis weir at Worcester. At Upper Parting some of the water turns into the eastern channel and meets the bore that has travelled up the Gloucester channel. It is a fascinating sight to see the river suddenly reversed as the incoming tidal wave overcomes the natural flow of the water and flows upstream. |
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| Flowing at a speed of up to 13 mph, the bore takes about 40 minutes to travel from Sharpness to Maisemore. |
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| Most of the year’s bores are unspectacular but each year there are about 130 days with high and medium bores up to six feet in height, twice each day. The height of each bore is notoriously unpredictable because there are several influences at work. |
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A few moments later the front wave is approaching Over lock and a flotilla of boats and surf boards rounds the bend |
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| Firstly, the height and
speed of the tide which is trying to enter the narrowing and shelving estuary varies
through the lunar month. The highest tides follow a few days after new and full moons and
the largest 50 bores of the year occur in the periods February to April and August to
October, around the spring and autumn equinoxes. The record height is 9¼ feet. Other influences are the amount of fresh water in the river, the atmospheric pressure and, finally, the direction of the wind. Strong winds from the west or south-west out in the Atlantic Approaches will increase the bore’s height. The tide is the most important of these influences but while tides can be predicted with great accuracy, the result of the mix of all four factors cannot. The result is that you can easily check when a bore will occur but you cannot be sure how spectacular it will be. A convenient vantage point for the bore is Telford’s bridge at Over but the bore is at its most spectacular on the section of river between Minsterworth and Lower Parting. Some of the best viewing points are:
Whichever vantage point you choose, you are likely to be astonished by the sheer power of the water, the increasing roar as it approaches and the dramatic change in river level once the bore has passed. |
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| Those who earned their living on the river learnt to treat the bore with respect and would listen for cries of "Tide Ho!" as it approached. It is vital to cope with the sudden changes in water level because a tightly moored vessel can easily be torn from its lines. |
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The boat is keeping just ahead of the bore |
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It must have been a bizarre sight to see a river tug and its train of barges each in turn thrust upwards as the bore passed beneath them. Recently an untended 100-foot barge, The Arreton, broke its moorings during a spring tide and grounded two miles downstream on the river bank at The Rea. Riding the bore has become something of a local sport. Fred Rowbotham recounts the story of a Colonel Churchill who approached him for advice about the possibility of riding it on a surf board. He made the attempt in 1955 starting from Stonebench and finishing, capsized, at…Stonebench. |
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About a dozen times each year the bore is large enough to be ridden and this has been done with all manner of river craft including canoes and windsurfers as well as surf boards. Two local surfers, Dave Lawson and Steve King have vied with each other for the longest wave ride. Lawson held the record first by completing 2.7 miles up to Maisemore weir. |
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| He has now increased this to 5.7 miles by starting further downstream at Upper Weir Green near Stonebench. This feat took nearly 40 minutes of | The main wave
of this quite modest bore |
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| concentration, moving from bank to bank to maintain the most favourable water. The record cannot now be extended because the wave below Stonebench is too shallow and the Maisemore weir presents an artificial end point. |
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| The linked table tells you predicted bore times for the year. | Even this modest bore at the tail end of 1999, caused quite a stir on the river bank opposite Over Lock |
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| Remember the bore can be
up to 20 minutes early or late. Think twice before selecting your car parking space and
take care where you are standing as the wave approaches! When our Visitor Centre opens you will be able to view the bore from the comfort of the Tea Garden! If you'd like to know more about the bore, follow the link to Chris Witt's "Severn Tales" on the links page. © NJ Bailey |
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Minsterworth – the road is right beside the river and river access
can be gained at the Bird-in-Hand, by the old ferry or at the church
