Mill Stream Weir, England

Reopening a 19 km stretch of the river, fostering fish pathways, facilitating sediment transport, and inspiring communities to engage in barrier removal and channel restoration for a healthier river ecosystem.


The Evenlode sub-catchment, a tributary of the Thames Valley, traverses Gloucestershire, Oxfordshire, and a small part of Warwickshire. Predominantly rural, with key settlements like Moreton in Marsh and Chipping Norton, the river flows through a wide valley amid an agricultural landscape. However, steep limestone hills with woodlands and grassland characterize the middle sections, falling within the Cotswolds Area of Outstanding Natural Beauty (AONB). Historically designated an EU salmonid fishery, the river faces challenges, including water pollution, leading to declines in fish populations, particularly Barbel, and poor water quality throughout much of its stretches.

At a glance

Project typeDemolition
Project statusLive
Demolition dateMay 2024
Km to be opened up19
Focal speciesSalmonid fish, Eel, coarse fish and otters

Project context and opportunity

In stream structures are just one factor contributing to the challenges the Evenlode faces, although a crucial one impacting hydromorphology, species, and water quality, causing environmental and socio-economic disruption. This project aims to address these issues by providing removing a dam and enhancing hydromorphology and socio-economic services, particularly welcomed by the ECP. The historical decline of European eel due to river barriers and pollution, the invasion of signal crayfish, and water quality degradation from untreated sewage and treated effluent are pressing concerns for the catchment. While projects like fish passage improvements can motivate the water industry to address sewage pollution, the overarching need for clean water is vital. The pervasive pollution issue from sewage works underscores the urgency for immediate upgrades, as the current plans extend to unclear dates between 2025 and 2050.

Project aims

This project is crucial for reopening a significant 19-kilometre stretch of the Evenlode, approximately 25% of the river’s total length. This section has likely been closed since medieval times, and the project’s success is anticipated to create pathways for salmonid fish, reconnecting mid and upper-river sections. Additionally, it will facilitate vital sediment transport that has been obstructed by a centuries-old weir.

The project aims to showcase the benefits of removing obsolete barriers and restoring channels to landowners and communities, emphasizing their role in enhancing fish stocks and fostering a healthier river ecosystem. Regular updates and engagement with local stakeholders, including councillors, anglers, farmers, and charities, are planned to encourage the scaling up of barrier removals and channel restoration initiatives.

With hopes that the success of this project will motivate similar efforts at other sites with old structures, the Evenlode can evolve into a more free-flowing waterway. The Environment Agency’s goal to reintroduce the eel into the Evenlode aligns with this project’s objectives, contributing to the species’ revival and controlling invasive crayfish populations.