The Kennet in November
As the nights draw in, the river levels are slowly starting to rise and trout are beginning to move upstream in search of good spawning grounds. There is a reassuring cycle to the life of the river, but every year we seem to be hitting new records of temperature and rainfall, which threaten to disrupt this natural cycle.
Chalk streams prefer gentle constancy, rather than the extremes we have seen in recent years.
One of the problems caused by intense heavy rainfall events is that more mud and silt is washed from fields and roads into the river. By contrast, prolonged steady rainfall soaks into the ground, allowing water to be filtered through the chalk before it reaches the aquifer and enters the river, clean and sparkling, via springs.
Local River Keeper John Hounslow has spent this week power-washing the gravel on the river bed. It sounds a strange thing to do, but mud and silt blocks up the gaps between the gravel, so that when fish come along to spawn they either can’t find a suitable gravelly place to lay their eggs, or they lay eggs which are then suffocated by the silt.
At the same time John has been experimenting with ‘seeding’ reaches of river with the plant ‘stream water crowfoot’ (ranunculus). Over the last 20 years large stretches of river have lost their healthy stream water crowfoot, an important plant in chalk streams.
No one is sure why the weed has died off, but one certainty is that it needs a strong winter flow to encourage growth. Flows are reduced by water abstraction, so this is a contributory factor.
To re-establish water crowfoot the river needs a source of roots and seeds, so John has been harvesting the roots disturbed by gravel washing and releasing them upstream, in the hope that some of it takes hold and grows to fill in the bare reaches below.
You can find out more about life on the river by joining us at our AGM on Monday 24 November in Marlborough Town Hall, starting at 7pm. We have talks on eels, work to reduce water abstraction and pollution, as well as an update on all our projects.
Everyone is welcome and we hope you will stay for a drink and chat afterwards.
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