NRW completes major river works to support wildlife on Afon Gwyrfai

Natural Resources Wales (NRW) has successfully completed a programme of improvement works at Bontnewydd weir on the Afon Gwyrfai, removing barriers to fish and eel migration and strengthening the riverbank for the future.

The project began in April and was completed in mid-September 2025. It involved replacing the rock barrage immediately downstream of the weir with a new structure designed to allow fish to move upstream more easily.

An eel pass was also installed by modifying the surface of the weir to create a rough, brushed finish that eels can grip onto. In addition, the left-bank wing wall, which had been undermined, was repaired to protect the integrity of the structure.

To minimise disruption to the river and local community, the work was carried out in stages, with only half of the river channel dammed at any one time. This ensured that water continued to flow throughout the project.

The site has now been fully restored, including reseeding the adjacent field in consultation with the landowner.

Sian Williams, Head of North West Operations at NRW, said:

“Bontnewydd Weir provides important data that supports our flood warning service; however, we also need to ensure that these monitoring structures do not create a barrier to migratory fish.

“These improvements will make a real difference to the health of the Afon Gwyrfai by helping fish and eels move freely along the river. This is vital for maintaining healthy fish populations and supporting biodiversity.

“We’d like to thank local residents and landowners for their patience and cooperation while this important work was carried out.”