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C.A.T.C.H. Open the Weir Near Hawkers Bridge VIDEO

Monday 27 April 2015, 10:41
By Dave Smith

On Sunday 19th April 2015, the C.A.T.C.H. team removed a sluice gate in the weir near Hawkers Bridge, Wincanton. You can see the whole process in the video above.

There are two weirs bookending the Wincanton stretch of the River Cale, cutting the habitat into sections. Fish are unable to pass back up through them to reach up-stream, so the biodiversity of the river habitat is damaged.

Unfortunately the weir at the bottom of town has been in place for about 50 years, since a local factory used water from the river as coolant. That factory has long since closed, almost 30 years ago, so it's about time something was done about the weir as a means of bringing the river closer to its natural condition.

The first, and most obvious option was to simply remove the weir. Being a substantial structure it would have required heavy machinery, qualified manpower and considerable funding to do properly.

Fortunately the weir was well designed, with two sluice gates. Opening the gates allows water to flow through unimpeded, so the flow of the river can be controlled. Opening just one of the two sluice gates allows fish to swim back up-stream, while still controlling the flow of water to create a diverse habitat. Leaving the bulk structure in place actually has purpose, so with the least effort, and cost, the team have achieved what is likely the best outcome.

The weir causes water to accumulate behind it until it reaches a depth necessary to flow over the top. The depth of the river is increased up-stream, to the place at which the river bed naturally reaches the same altitude as the top of the weir.

Just up-stream from the weir is Hawkers Bridge, below which there is an old ford (a cobbled section of road across the river bed - you can see it in the video at about 5:05). This man-made alteration to the river bed serves only to flatten it out, making it less useful to nature. This stretch of the river is also unnaturally deep because of the weir.

The new landscape under Hawkers Bridge, now the sluice has been opened.

Now that the sluice gate has been removed the level of the water has dropped significantly, revealing lots of interesting features of the river bed that were formerly submerged. The water now flows either side of a newly formed island between the bridge and the weir, for example. This should provide new opportunities for a diverse range of species.

C.A.T.C.H. hopes that now fish are able to pass back up-stream into the Town stretch of the river we might see the likes of brown trout. The presence of new and perhaps larger fish will change the balance of the food chain. We might soon see all kinds of new and interesting wildlife in our area. This simple change could have a profound and hopefully positive effect.

Time, and hopefully photography will tell!




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