Langford Mill Eel Screen Update

Finishing works on the Mill screen and surroundings are mostly complete now, the screen has passed a 28-day trial period successfully and it's now in normal operation. It will be monitored and maintained regularly by the local Operations team to make sure it continues to perform well through all seasons.

An information board has been provided to the Mill House Hotel to support any queries their customers may have about the project. There is a similar board at the Langford Museum of Power, why not pop along to the museum and take a look!

Langford Mill Eel Screen Update

The screen installation works at the Mill are complete and the screen wipe and wash system are now in operation. Optimisation adjustments and testing will continue over the next few weeks to maximise the screen's operating efficiency.

Peripheral works like fencing, pathways and reinstatement of the grounds will continue for a few days but should be complete by mid-February.

Langford Mill Eel Screen Update

The eel screen installation at the Mill has progressed rapidly in the last two weeks. The old screen structure was removed once the river was drained down allowing the new support framework and walkway to be installed in the same location.  The new wedge-shaped screen was then lowered into the river and connected back to the support structure. The mesh screening panels were set in place once the main structural installation was completed.

Works continue on the electrics, controls and debris removal systems as well as peripherals like an access pathway and new fencing. Testing and commissioning starts in earnest next week (from Monday 31^st January).

The attached photos show the recent progress and the screen in situ. Click on a photo for a larger view and to see the explanatory caption.

Langford Mill Eel Screen Update

The installation works have started on site this week so if you're in the area you may notice our contract team busy in and around the Mill building. The majority of the works this week have been inside the Mill working on the electrical installation whcih will continue into next week.

The screen fabrication team will be on site next week to start assembling the screen itself. The installation into the river is planned for the week beginning Monday 17th January, weather permitting. We will be working with the EA Fisheries team again to safely lower the river level and make sure any fish in the vicinity are protected. Lowering the water will allow the screen to be set in place without the need for divers working underwater.

Langford Mill Eel Screen Update

Works on the Langford Mill eel screen are continuing to progress well. The lowering of the river for inspection of the area was successful and fish protection was maintained throughout. Due to this success, the project team are now planning to lower the river level again for the installation of the eel screen rather than having dive teams working in the water as was originally designed. These works are scheduled for mid-late January 22, assuming weather conditions are suitable and the river is not in flood.

Most activities on this project are happening off-site for now; manufacture of the eel screen has been completed and the support structure and control systems are also being built off-site. There are likely to be some minor preparatory works in and around the Mill in the lead up to Christmas but the main site works will commence in the New Year.

Langford Mill Eel Screen Progress

Activities on the Langford Mill Eel Screen project are taking shape. This week the team have been preparing the site, installing temporary fencing and levelling the ground to create a safe working area next to the river. We had an archaeologist on site with the team today overseeing the levelling works in case of any historically important finds although nothing of interest was turned up.

Preparations are being made for the lowering of the river to enable the existing intake structure to be inspected. We're working closely with the Fisheries team from the Environment Agency to make sure fish are protected during these works. The EA will monitor the activity, checking the oxygen levels in the water and will assist with moving fish out of the affected area if required. It's hoped that this will all take place next week (from Monday 27th September), pending receipt of a permit from the EA. Further updates will be provided if the works have to be rearranged.

In addition to these site-based works, the eel screen fabrication is progressing well at the manufacturer’s workshop. When complete, it will be transported to site in sections and reassembled at the riverside before being lifted into place with a crane.

The Blackwater fish and eel pass project at Langford is also progressing. The outline design for the pass has been approved by the Environment Agency and is now moving into final design development for the construction phase. The pass will be located at the southern end of the existing weir structure approx. 130m upstream of Langford Mill. The attached General Arrangement drawing shows the location and proposed layout for illustrative purposes.

Langford Mill Eel Screen Works Commencement

We have engaged Farrans Construction for the installation phase of the Langford Mill Eel Screen project and preparations are being made to enable works to start on site at the beginning of September. Initial site mobilisation activities will include setting up of welfare cabins and preparing the ground with temporary hardstanding for the working area. The grounds will be returned to grass once the site works are finished.

The screen is currently being manufactured off-site and is expected to be delivered for installation in November. Whilst the screen is being fabricated, preparatory works on site will include surveys and inspections (including a 2-3 day lowering of the river level to enable inspection of the existing concrete structure), installation of an access platform, a pathway and electrical works inside the Mill building.

The scheduled site completion for the Mill Eel Screen is February 2022. As described in the section on Planned Work, there are two further associated projects in this area so there is likely to be a continuing construction site presence beyond the February end date for the Mill. As the plans for the other works are developed more details will be shared here on the portal in future updates.

Site Layout and Construction Development for the Langford Mill Eel Screen

Plans are developing now for the installation phase of the Langford Mill Eel Screen project. Currently works are expected to start on site around August 2021.

The drawing below shows how the site will be laid out once the installation is complete. The main elements to be constructed are marked ‘new’ on the drawing.

During construction, the site will be fenced off (as indicated by the dotted red line) to maintain a safe working area separated from any passers-by. The maintenance platform, pathway and control systems inside the Mill building will be constructed first whilst the screen is manufactured off-site.

When the screen is delivered for installation there is likely to be a crane on site for a short time to lift it into the river but for most of the time the site presence will be a few construction engineers and smaller vehicles. Our vehicles will access the site via the existing double gates off the B1019 Maldon Road (between the Mill and the village Hall). There are no road closures or long-term traffic lights anticipated to support the access arrangements but there may be occasional short duration traffic controls to enable larger vehicles to safely navigate the entrance. More details will become available on traffic management once the construction plans are in place.

Chosen Solution for the Langford Mill Eel Screen

To meet the legal requirements of 'The Eels (England and Wales) Regulations 2009' Essex & Suffolk Water have an obligation to install fine screening at our main raw water intakes to prevent eel entrapment within pumping systems. At the Langford Mill, the chosen option is a static 'Eco-Screen' which will sit in the river in front of the intake and water will filter through the fine mesh panels to the original pumps inside the Mill building. If the screen starts to block with the debris in the river, sensors will detect the difference in levels and will initiate an automated cleaning operation. This activates a wiper arm with bristles (like a large toothbrush) that will draw the debris up the screen to a trough and a wash water system in the trough will flush the debris into a catchment trolley which will be regularly cleared by our Operatives.

For the Eels Regulations, the key parameter is the speed at which the water engages with the screen, called the 'approach velocity'. This needs to be low enough to enable eels and fish to swim away rather than being drawn towards the screen and unable to escape. To achieve the right approach velocity the screen needs a large surface area. This meant that some screening types were not suitable for the Mill as the number of units and overall footprint would have been excessively large in this location, we therefore selected the most compact solution available to minimise the visual impact. The photomontage below depicts how the screen will fit with the existing structures. It will be a dark colour to blend in with the surroundings as much as possible.