Weir removals on the River Gelt

WTT’s Conservation Officer for the North, Gareth Pedley, walks us through a recent project which we’ve delivered in Geltsdale…

WTT has teamed up with project managers from the Environment Agency’s Cumbria River Restoration Strategy Programme and Water Resources Decommissioning of Unused Assets Programme to remove two redundant flow gauging weirs on the River Gelt near Castle Carrock, in the River Eden catchment.

The benefits of removing almost any obstruction in a river are wide-ranging, but in this case, from WTT’s perspective, the most important aspect was improving fish passage and restoring natural river processes on the Old Water and New Water of the River Gelt. It was also very helpful that complete eventual removal of the weirs had been stipulated by the landowner at the time when they were originally installed, to ensure that redundant structures would not be left littering the countryside! This greatly simplified the whole project, as there is usually a significant amount of discussion and negotiation required before obstructions can be removed. 

The river restoration company, Dynamic Rivers, oversaw the design of the removal process, starting with a full assessment and options appraisal, with WTT steering the project towards full removal to renaturalise the channel, without leaving any legacy structures in the river. The result should allow a more natural adjustment of the channels to occur over future high flow events. 

The images below show how the Old Water has adjusted in this way, after the weir was removed.

1 Old Water Before
2 Old Water After

The whole removal process went very smoothly: pre-works fish rescues highlighted healthy numbers of trout around both weirs, and we relocated the fish upstream of the site to allow the contractors and their machinery to work freely. Undoubtedly, these fish will already be recolonising their lovely new habitat. The large pools of the United Utilities intakes (which create further obstructions downstream) also aided the weir removal process by acting as secondary sediment controls, limiting the impact of the fine sediment mobilised by the work. Work on both weirs was just about completed within the originally predicted two-week timeframe, with just a short delay from high water.

While there are still two major, manmade obstructions just downstream of our work site (United Utilities’ intakes), our project will allow fish trapped upstream of those obstructions to easily ascend back up the catchments, and these removals also give greater impetus to improving fish passage at the remaining obstructions downstream. The work undertaken will allow naturalisation of both channels by reinstating the natural river processes previously inhibited by the impoundments of the weirs, to the benefit of fish and invertebrates.

Whenever opportunities arise, removing redundant and low value weirs like these, all around the UK, will be vital to improve riverine habitat and provide natural, uninhibited access for fish around their native catchments — as shown in the before’ and after’ images from the New Water weir removal site below.

3 New Water Before
4 New Water After

The Wild Trout Trust would like to thank the Environment Agency for entrusting this important work to us, Dynamic Rivers for undertaking the feasibility and detailed design, United Utilities for accommodating the temporary disruption to their operations, the landowners and tenant for their relaxed approach to the work, and O’Malley Groundworks for undertaking the removal. 

For more information about the impact of weirs, take a look at our Weirs, Barriers and Hydropower’ page HERE.