Nature

River Mel Restoration Group

As we write this we are fresh from attending a training session for volunteers from the River Mel Restoration Group, led by Rob Mungovan of the Wild Trout Trust, demonstrating the management of in-channel waterweed. The improvements to the River Mel over the past few years have led to a welcome increase in growth and diversity of the in-stream vegetation associated with chalk streams. The purpose of the training was to demonstrate ways of managing the growth of this in-river weed to the benefit of the river and its wildlife.

Vegetation needs to be cut in a manner that creates channels through the beds of weed so that the water does not become impounded upstream, but this has to be balanced against removing too much weed and so risking dropping the water levels too far in summer. If left uncut, the clumps of weed can grow so large that they restrict the flow and lead to erosion of the bank so causing over widening of the river. As our work in the river has been to increase flow rates by selective narrowing of the river this is something we need to avoid.

Rob provided one-to-one tuition in the river, demonstrating the use of a scythe to both shave off the top growth (rather in the manner of spoke shave on wood) and how to ‘guillotine cut’ the sides and downstream tails of the clumps of weed. Like a lawn, the weed grows better if cut ‘little and often’. This type of trimming also has the advantage of extending the growing season of the plants, thus providing a longer period of cover for fish and invertebrates that live in the river. Studies have shown that managing weed in this way also increases the ability of the plants to over winter, thus encouraging earlier, beneficial, growth the following season.

It was clear that this process needs care and patience, as it would be very easy to damage the delicate ecosystem of the chalk stream by over-cutting. In addition, the cut weed needs to be removed to the edge of the banks, so that any small fish and invertebrates inadvertently caught up in the trimmings can find their way back to the river. That said, it was a very pleasant occupation that coincided with the first really nice evening of the Spring.

The Wild Trout Trust regularly deliver improvements on some of England’s best known chalk rivers. It is to their credit that this care extends to the smaller chalk rivers such as the Mel and the Shep.

For further details about volunteering or the dates of future working parties, please contact Maureen Brierley on 01763 262752.