Surrey river restoration to tempt brown trout upstream

© Linda Pitkin/2020VISION

A River Mole Catchment Partnership project to restore the natural course of the Rye Brook, near Ashtead in Surrey, is helping to encourage brown trout upstream and capture flood waters.

The project has reprofiled river banks, added natural bends and meanders and created a large pond alongside the river.

Funded by the Environment Agency and Mole Valley District Council, the South East Rivers Trust produced the wetland design for the project which hopes to create new spawning grounds for brown trout and habitat for other wildlife as well as provide flood alleviation.

Some seventy years ago the Rye Brook was straightened for efficiency and convenience of land management. However, the lack of natural bends and faster flowing water meant detrimental impacts on Brown trout, which had fewer places to spawn.

So project managers, the Lower Mole Countryside Partnership, worked with contractors to reprofile 200 metres of river in November 2020 with excavators, reinstating those vital meanders. It is hoped this will help kick start the natural river processes that maintain instream habitats for wetland wildlife and provide a natural solution to flood defenses.

Glen Skelton, wetland landscapes officer at Surrey Wildlife Trust, said:

“In the past rivers were often straightened and moved to the edges of fields to help drain the surrounding land and make farming operations more efficient. So rivers like the Rye Brook were unable to function naturally.

In high flows wildlife is flushed through and in low flows, the river silts up and smothers the gravel beds and aquatic invertebrates that live on them, leaving the river in a sorry state for wildlife. This project will help to reverse some of these impacts.”

The new meandering path of the Rye Brook and gentle gradient of the river banks means the water can move naturally from side to side and reconnect to wetland areas on the flood plain. So now the new pond can provide refuge for fish during high storm flows and the restored channel will provide important habitat for invertebrates such as the mayfly, and fish, such as, brown trout and Millers Thumb.

Conor Morrow, senior countryside partnership officer with the Lower Mole Partnership, said:

“This shows what catchment partnerships can deliver, when local knowledge and specialist skills can be brought together to make real improvements to the river habitat.”

Works will look stark initially but next spring aquatic plants such as starwort will recolonise the river. These plants form floating mats which provide food for invertebrates such as the caseless caddisfly which will in time become food for fish.

This eight year project to restore the Rye Brook and remove barriers to fish passage could not have come to fruition without the involvement of a large number of partners in the River Mole Catchment Partnership.These include: The Friends of Ashtead Rye Meadows who restored 400m upstream, the Lower Mole Countryside Partnership, Surrey County Council Countryside team who restored 300m downstream, where the Rye Brook meets the River Mole, and funding from Mole Valley District Council. Other partners on the project include Friends of Teasel Wood and Friends of the River Mole.

By working together in local partnerships such as these, Surrey Wildlife Trust aims to achieve their mission of recovering 30 per cent of Surrey’s landscape for nature by 2030 and connecting people with their local wildlife.