In what was one of the worst seasons for Wye salmon catches on record, there was a least some good news from the river Elan this autumn.

This river’s potential as a salmon and trout spawning tributary has been decreasing following the completion of the Elan dam complex in 1904. Since then, vital river gravels in the 7km section downstream of the dams have steadily washed out while their natural replenishment has been cut off. This process had led to a deterioration in the river’s overall ecology, leaving it in an increasingly impoverished state.

In 2016 only 9 salmon fry were found in the Elan. In 2019, 165 were recorded.

Added to this was the dams’ effect on the amount of water flowing down the Elan as they filled up each year. This meant that the river was often at minimum flow during the autumn, just when salmon and trout need extra water to ascend and access their spawning areas.

Over a century later, fish spawning in the Elan had been limited to just a few sites near to its confluence with the Wye.

In 2016 the lower Elan received its first new gravel for over a century

Restoration Starts

In 2016 the Foundation, along with its partners Natural Resources Wales and Dwr Cymru Welsh Water began re-introducing new gravel to the Elan just downstream of Caban Coch, the lowest of the dams. In the past three years over 3,000 tonnes has been put in, sourced from various sustainable sites across the upper Wye and Elan catchments.

Alongside the gravel project, the Foundation and its partners (via the Usk Wye Abstraction Group or UWAG) have managed to change the way in which water is released from the dams across both river catchments. Release programmes are now moderated to take into account the needs of migratory fish, enabling them to ascend rivers more easily. In combination with the new gravel, this means that much more of the 7km of the Elan downstream of Caban Coch is now available to them.

The extra releases from the Foundation monitoring staff undertaking invertebrate surveys in the Elan in March 2019dams also help in dry summer conditions. During 2018’s drought, the Elan was making up over 75% of the combined flow at the confluence with the Wye. Without this extra water, the state of the river would almost certainly have been unthinkable.

Read more about the work of UWAG

Results

In terms of the Wye’s salmon, the results of these two projects have been heartening at a time when numbers of returning adults have appeared to have dropped again after a period of recovery.

During the Foundation’s September 2019 electrofishing surveys, salmon were found to have spawned in the Elan’s newly introduced gravel for a second consecutive year. Salmon fry are now present in these areas and there has been a large increase in fry and parr numbers further downstream.

Juvenile salmon and trout recorded during our Elan surveysThe results from the Elan show that there is a workable solution to the negative effects of dams on salmonid populations across the UK.

Juvenile salmon were also found further upstream than ever before in the section opposite Elan Village. Meanwhile, salmon fry were found in 4 and trout fry at 6 of the 7 monitoring sites within the section that was previously denuded of gravel and fishless.

In 2016 only 9 salmon fry where caught in the whole Elan survey. In 2019, 165 were recorded.

2016 Elan Salmon Fry Electrofishing Map

2019 Elan Salmon Fry Electrofishing Map

This recovery in fish populations has followed a marked improvement in the river’s invertebrates, which are the essential food source for juvenile salmon and trout of all sizes.

Both projects have been a positive for salmon at a time when good news has been in short supply. The gravel project in particular is receiving widespread acknowledgement. Welsh Water’s Director of Environment, Tony Harrington, said last year: “We are delighted with the results of this project. Welsh Water supports an evidence led approach to nature conservation, and this is a great example of where our funding to restore a habitat has delivered real ecological improvements.”

Peter Gough, Senior Fisheries Technical Specialist for Natural Resources Wales noted the wider implications of the project: “Depletion of gravel below dams occurs in many rivers in the UK. The results of this work on the Elan show that there is a workable solution to this.”

In 2019, the project has also been shortlisted for the prestigious Charles Ritz Award.

The Future

Yet despite proving its benefit, the future of the gravel project is by no means secure. A lack of funding and an unwillingness by riparian owners to give their consent for gravel removal, even though recovery of all donor sites so far has been rapid, could bring it to a premature halt.

The Elan still requires a further 3,000 to 4,000 tonnes of new gravel to enable it to attain somewhere near its full potential. With no natural replenishment, it will then require top-ups every three years. Such introductions are relatively small and cost-effective but they do require an agreed and consented donor site, which will be depleted of a small amount of gravel for a short period.

However, the net benefit of such an operation to the environment is hugely positive. Without it, the Elan will return to its pre-2016 state of impoverished ecology and low to non-existent fish populations.


Project Partners

Our thanks to project partners Dwr Cymru Welsh Water, Natural Resources Wales and to the Elan Valley Trust.