Starnthwaite Ghyll Weir removal, United Kingdom

Introduction

Flowing 18 km through the Lake District National Park in Cumbria, England, lies the River Gilpin. This river joins the River Kent SSSI/SAC before reaching the estuary that flows into Morecambe Bay. Agricultural pressures and barriers to fish migration have been identified as key factors contributing to the decline in water quality and limiting access to vital habitats within the Gilpin catchment. Although there are only two weirs on the River Gilpin, they obstruct migratory routes and negatively affect fish populations. The removal of Starnthwaite Ghyll weir, the furthest upstream, will restore access and connectivity to upstream habitats. This includes valuable spawning and refuge sites for UK Priority migratory species, such as the Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). Standing 1.75 metres high by 12 metres across, removal of this barrier will also enhance migration success, particularly for species journeying to the sea.

Project context and opportunity

South Cumbria Rivers Trust (SCRT) has been working on the removal of Starnthwaite Ghyll weir since 2021. The weir, built in the 1930s to provide power to the local school, no longer serves its original purpose. Weirs were historically constructed without consideration for the environment, including natural river processes. Following its partial collapse, further deterioration has become a risk to surrounding properties. Removing this barrier in a safe and controlled manner will not only eliminate liability for landowners but also reduce potential risks to the wider community. Additionally, this project will improve access to upstream spawning grounds and habitats for priority species, including Atlantic salmon (Salmo salar) and brown trout (Salmo trutta).

The initiative will complement proposed mitigation efforts at the downstream barrier, facilitating migration along the entire watercourse. This will be the first weir to be removed on the River Gilpin, and it has received considerable support from the local community and the structure’s owner following several months of engagement.

Project aims

The project focuses on removing Starnthwaite Ghyll weir, easing migration routes and improving access to upstream habitats. This weir removal alone will open up 13.5 km of additional habitat for priority species, including brown trout (Salmo trutta), Atlantic salmon (Salmo salar) and the critically endangered European eel (Anguilla anguilla). In addition to enhancing local biodiversity, removal of the weir will contribute to improving the Water Framework Directive (WFD) status of the watercourse, which is currently classified as heavily modified.

This barrier is identified as one of two critical migration and hydro-geomorphological blockers in the system. It is also the only one lacking a functional fish pass. Beyond ecological benefits, this weir removal project supports the local community by addressing a potential risk to nearby properties, ensuring both environmental and public safety improvements. With additional mitigation measures planned for the second weir in this river system, we expect to see an increase in priority species accessing the upstream habitat. SCRT will assess this through monitoring programmes such as electrofishing, which evaluates fish abundance and species composition.