Removal of Dove Cliff weir - information page

Overview

Page created July 2019. Last updated 9 November 2021.

"Weir" finished! We are pleased to update that on 15 October 2021 our contractor, Stonbury, completed the construction phase of the weir removal project.

Project timeline

Good weather and flow conditions in September and early October have enabled us to complete the reinstatement of the local land and, therefore, all of the construction works at Dove Cliff weir.

A considerable amount of effort has been undertaken to ensure that the field previously containing the temporary bypass channel has been returned to its original state. As part of that reinstatement the field on the north (Derbyshire) bank has been sown with a native wildflower meadow mix. This was undertaken by volunteers from the Transforming the Trent Valley wildlife team and, due to the unseasonably warm autumn weather, it is starting to grow quite nicely.

Stonbury have also restored the fields on the Staffordshire side where the main compound and the access roads were located. These have been grass seeded with a native grass mix where fields are not used for growing crops.

Photograph above looking upstream from the new entrance to the mill fleam.

Dove Cliff weir

Following the completion of the works, the channel consists of a more natural river bend, with a deep faster flowing section on the outside and a shallower flowing section on the inside, as shown in the images below. The mill fleam has been reconnected on the outside of the bend to ensure the flows are maintained.

Below is an aerial photograph looking down at the new river alignment where the weir used to be, adjacent to the aerial view design illustration.

Above Left: August 2021 aerial photograph of completed permanent works. Above Right: Artist impression of completed project.

There will be some specific landscaping whereby we will replant native trees and shrubs in place of those that were removed to enable the works to be undertaken. This will happen over the next few weeks, depending on when there is suitable cold and dry weather conditions, to align with their planting season.

Archaeology

The analysis of the archaeology which was discovered on site is still ongoing with the final report expected in summer 2022. We will make this publically available when it is completed.

Monitoring

We have now entered into the important post construction monitoring phase of the project, with elements of that continuing for a number of years. It includes flow and water level monitoring in the river, both upstream and downstream of the main site location, as well as further flow monitoring in the mill fleam. The groundwater levels will also continue to be monitored, particularly how they link with Podmores Pools upstream of the site location, and the progress of the gravel bars and banks of the main channel.

Opening ceremony

On 15 October 2021 we held a media event to celebrate the completion of the project. At the event, we were able to demonstrate the work we have completed to open up the River Dove for the first time in nearly a millennium, creating a better place for people and wildlife.

ITV Central interviewed both our Technical Fisheries Specialist and Senior Project Manager at the event, with coverage on BBC East Midlands, BBC Online: https://www.bbc.co.uk/news/uk-england-derbyshire-58915696, Staffordshire Live: https://www.staffordshire-live.co.uk/news/local-news/huge-project-remove-entire-weir-6066043, Burton Mail, Greatest Hits Derbyshire Radio and Swadlincote Post and national trade media.

Read more:  https://www.gov.uk/government/news/removal-of-dovecliff-weir-restores-river-health

View a video about the project: https://twitter.com/EnvAgencyMids/status/1455862471613468673

Image above - Talking about why fish migration and clean river gravels are so important with ITV.

Open house event in 2022

We are hoping to have a public open house event next to the river in May 2022 as part of World Fish Migration Day. If you are interested in hearing more about this event and would like to be kept informed of the details as they develop, please let us know using the contact details in the green box at the bottom of this page.

Benefits of weir removal

Weirs were historically designed and installed to control water and at that time the environmental impacts of their installation weren’t fully considered or understood.  It was later discovered that they altered natural functions of rivers and their connection with the floodplain, impacting on water quality and adversely affecting aquatic ecology and the wider surrounding environment. Removing a weir improves water quality by allowing water to flow naturally.

Fish and invertebrate species also greatly benefit from weir removal as weirs act as barriers to their movement. Weir removal benefits all aspects of aquatic ecology, including recovery of the riverbed and banks, and development of a more diverse habitat.  A greater diversity of fish and invertebrate species is documented both up and downstream following weir removal.  We are already seeing the benefits of weir removal upstream of the site with the formation of gravel bars and improved habitat for invertebrates and spawning fish as shown below.

Photographs - (Above left) Exposed river sediment is important habitat for diverse communities of beetle, birds and plant species. (Above right) Dove Cliff weir with salmon attempting passage.

Outdated weirs which no longer serve a purpose frequently fall into disrepair and become economically unfeasible to maintain and replace. The public safety risk associated with these types of structures should not be underestimated.  Every year there are numerous unfortunate incidents of people drowning in the dangerous conditions around weirs.

Fish rescues

From March to June 2021 the site had remained isolated, therefore, no fish rescues were required. This was great news as it meant we had no impact on spawning coarse fish during the important breeding period.

The temporary bypass was isolated in late July. Fish rescues were carried out before completely dewatering the channel so the reinstatement works could commence.

To date, during our fish rescues 16 different fish species have been recorded including Gudgeon, Bullhead, Perch, Chub, Dace, Stone loach, Grayling, Eel and Brown Trout.

Background

We have removed Dove Cliff weir (pictured below) to improve biodiversity and improve fish passage through the entire Dove catchment. Dove Cliff weir was structurally assessed in 2016 and sections were found to be in a poor condition. This led to all options for managing the weir being investigated.

The best solution for fish passage in our rivers is to remove barriers, such as weirs and sluices. This is particularly important when they are in poor condition, can cost a lot of money to maintain and no longer serve a functional purpose.

Fish passes alone do not improve the habitat required for fish to spawn and grow. However, removing weirs does as it allows the sediments within the river to deposit naturally creating the right river environments.

Frequently asked questions

Will the removal of the weir effect the water levels in the river?

With Dove Cliff weir removed, the water level upstream of the weir will drop. The water level is expected to drop by approximately 1 metre immediately upstream of the weir. Due to the natural slope in the riverbed, the further upstream you go the less change in water level you will see. There will be no change in river level upstream of Rolleston Brook where it enters the River Dove.

The reduction in water level will be a benefit to the environment as it allows the river to function in a natural way, creating both shallow and deep sections within the river. Shallow river sections are just as important to biodiversity, especially fish, as they provide the right conditions for small fish to grow after they hatch. 

How will flows in the mill fleam be affected by this project?

Maintaining a similar flow split between the main river and the mill fleam (mill leat) was an important design criteria for this project. With the construction work now complete, we are monitoring the flows in both the mill fleam and the main river to confirm this and will continue to undertake monitoring across the full range of flows in the Dove.

Further information

As we have now completed construction all future updates to this page will be on an ad-hoc basis when there is information that is deemed to be of public interest and value.

Look out for #Dovecliff updates on our twitter feed too @EnvAgencyMids.

Thank you for visiting our project information page.

External website links that may be of interest

https://yearofthesalmon.org/
https://www.damremoval.eu/
https://www.worldfishmigrationday.com/home