Usk

On Friday, the warmth spread further south and Wales recorded its joint highest temperature of the year so far with 22.4C at Usk in Monmouthshire.

It explained the 225-year old canal, which once transported iron and coal to Newport docks, had relied on funnelling water from the River Usk and its tributaries, which accounted for between 80% and 90% of its water supply.

Environmentalists warned limits on the water taken from the Usk were needed so species and habitats had sufficient water to survive.

The River Usk is a designated special area of conservation protected by law, due to its importance for rare wildlife including the Atlantic salmon, which is threatened with extinction from Wales.

Water will start being taken from the Usk Reservoir between Brecon and Llandovery from the early hours of Saturday.