A RESTORATION project has extended the distance fish are able travel along an Oxfordshire waterway.

The River Thame Conservation Trust has partnered with the Environment Agency on the conservation scheme which aims to allow fish to navigate past a stone weir at Waterstock Mill near Wheatley.

The structure has long inhibited the passage of aquatic fauna along the waterway, disrupting lifecycles.

The River Thame runs 40 miles from north of Aylesbury in Buckinghamshire to the village of Dorchester on Thames near Wallingford.

Its many brooks and streams wind through both counties providing beautiful areas for people and wildlife.

The river has also been a major source of power in the rural economy, with weirs constructed to services local mills.

However, these industrial structures have proved detrimental to fluvial ecology.

Fish have been unable to adapt to manmade alterations to waterways, with devastating implications for species survival.

Natalie Breden of the River Thame Conservation Trust said: “Habitats which were once continuous have been divided by weirs, restricting the movement of fish and insect species.

“Dredged river bottoms, straightened channels and blockages such as weirs and sluices, which dissipate the flow of water and block movement, have severed fish from food sources and habitats.

“This can badly affect their survival and some species can disappear altogether in some stretches of river.”

Waterstock Mill, a historic Grade II-listed building, has been one such obstruction.

The structure, once operated as a corn mill, and is even mentioned in the Doomsday Book.

It has since been converted into residential accommodation, however fish passage continued to be obstructed by the sluice.

Such obstructions also enhance detrimental impacts of pollution in the river.

Ms Breden said: “Blockages in the river prevent fish and other mobile species from moving away from the pollution and being able to re-colonise after the events.”

Previously, the high sluice in the river by the mill acted as a dam, meaning fish could not get upstream at that point except when the water level was at its highest.

The conservation trust team put in a new underwater wall just downstream of the sluice to create a small pool which the fish can now use as a stepping stone to get upstream across the sluice.

The Waterstock Mill project also restored more than half a mile of river, with critical support from the local landowner who allowed the work to take place on his land.

The River Thame Conservation Trust now hopes to carry out similar projects in the coming years to gradually improve passage and habitats across the river catchment.