The ACA Forum

Conserving the Devonshire Avon from source to sea


by | May 6, 2022 | Main | 0 comments

As a ‘spate’ river, the levels of water in the Avon can rise and fall dramatically in response to rainfall; an effect made even more acute by the construction of the Avon Dam in the early 1950s, which effectively shut off much of the water and gravel flow arising from the moors.   During dry weather, the effects on all water-dependent species can become quite stressful but especially so for migratory fish species depending upon suitable water depths to complete their complicated life cycles at particular times of the year.   For over half a century, compensatory water releases or ‘freshets’ from the dam during dry weather were not activated although they had been agreed prior to construction.  However, during a prolonged series of meetings between 2011 and 2016, the Devon Avon Group (convened by the ACA and comprised mainly of ourselves,  the Avon Fishing Association, South West Water -SWW- and the  Environment Agency) successfully negotiated the activation of these water releases  by SWW to ameliorate low flow during dry weather in the April/May period.  Happily,  this long-overdue arrangement has continued quite well since those negotiations and I have just been informed by the Environment Agency that following a prolonged period of dry weather, during which there has been a period of consistent low flow downstream of Avon Dam with no realistic possibility of the dam ‘overtopping’ in the near future, that they have arranged for a ‘freshet’ to be provided to facilitate smolt migration. The increased water flow will start on Wednesday 4th May at 1500h and finish at 0900h the following day, to be followed by another ‘freshet’ on Wednesday the 18th May at 1500h if flows remain low.   (Smolts are young salmon or sea trout – about two years old – that are at the stage of development when they assume the silvery colour of the adult and are ready to migrate to the sea).  Unfortunately, planned research to objectively measure the effects of these water releases on the river’s ecology has never come to pass owing to resource shortages within the monitoring agencies but the effects in the shallower parts of the upper river, at least, should be significant.



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