Category Phase One: Grand Sluice   Show all

  • Phase One: Grand Sluice April 2026

    After an extremely wet winter, work on the sluice refurbishment is ready to restart. Our contractors will begin by installing the stop log liners. These are steel channels that hold temporary dams called “stop logs”. The stop logs let us block off the channel in a controlled way so that we can dry part of it out. Once the area is dry, we’ll be able to safely remove and replace the sluice gates. You can watch a short clip of stop log liners being lifted into position in our Videos section- Videos | Lower Witham Flood Resilience Project | Engage Environment Agency.

    This year’s activities will include grouting the downstream liners and installing the upstream ones. This is particularly challenging as the downstream phase will depend on suitable tidal windows, while upstream work will involve divers operating in the river. You may notice floating craft working on the sluice both upstream and downstream while this happens.

    Workers in orange hi vis clothing stand in shallow water in the channel at Grand Sluice. They are beside a red barge with a crane that they are using to carry out works on the structure. Contractors using a crane on floating craft downstream of Grand Sluice.
    Multiple work boats and floating platforms are positioned beneath a metal bridge in the river channel. Workrs in protective clothing stand on the barge with a crane. A small metal boat is tied up alongside, green plant material can be seen floating on the surface of the water. Fencing, scaffolding and signs are visible along the edge of the river and bridge structure. Contractors using floating craft upstream of Grand Sluice.

    Progress has been slower than planned, and completing the installation of the stop log liners is expected to take the rest of this year. The stop logs themselves have already been made and are being stored ready for use. You can see a video of the stop logs being factory tested using a special rig designed to mimic site conditions in our Videos section- Videos | Lower Witham Flood Resilience Project | Engage Environment Agency . In the future we will begin replacing the main sluice gates. We will also install an overhead monorail beam which we’ll use to move and position the stop logs when needed.

    As before, work will pause again over the winter months. In the meantime, we will post regular updates as activity on site continues throughout the year.

    After an extremely wet winter, work on the sluice refurbishment is ready to restart. Our contractors will begin by installing the stop log liners. These are steel channels that hold temporary dams called “stop logs”. The stop logs let us block off the channel in a controlled way so that we can dry part of it out. Once the area is dry, we’ll be able to safely remove and replace the sluice gates. You can watch a short clip of stop log liners being lifted into position in our Videos section- Videos | Lower Witham Flood Resilience Project | Engage Environment Agency.

    This year’s activities will include grouting the downstream liners and installing the upstream ones. This is particularly challenging as the downstream phase will depend on suitable tidal windows, while upstream work will involve divers operating in the river. You may notice floating craft working on the sluice both upstream and downstream while this happens.

    Workers in orange hi vis clothing stand in shallow water in the channel at Grand Sluice. They are beside a red barge with a crane that they are using to carry out works on the structure. Contractors using a crane on floating craft downstream of Grand Sluice.
    Multiple work boats and floating platforms are positioned beneath a metal bridge in the river channel. Workrs in protective clothing stand on the barge with a crane. A small metal boat is tied up alongside, green plant material can be seen floating on the surface of the water. Fencing, scaffolding and signs are visible along the edge of the river and bridge structure. Contractors using floating craft upstream of Grand Sluice.

    Progress has been slower than planned, and completing the installation of the stop log liners is expected to take the rest of this year. The stop logs themselves have already been made and are being stored ready for use. You can see a video of the stop logs being factory tested using a special rig designed to mimic site conditions in our Videos section- Videos | Lower Witham Flood Resilience Project | Engage Environment Agency . In the future we will begin replacing the main sluice gates. We will also install an overhead monorail beam which we’ll use to move and position the stop logs when needed.

    As before, work will pause again over the winter months. In the meantime, we will post regular updates as activity on site continues throughout the year.

  • Phase One: Grand Sluice

    Since our last update in July, work has continued at Grand Sluice to prepare the structure for its full refurbishment. Our contractors Jackson Civil Engineering Ltd. have been carefully installing stop log liners. These are essential as they will allow us to safely dewater the channels when the main refurbishment begins.

    Working with the tides on the downstream side has been particularly challenging. At low tide, the team can work on the bottom sections in dry conditions. But when the tide is higher, they need boats to install the liners.

    Upstream, significant work has taken place on the apron. Many

    Since our last update in July, work has continued at Grand Sluice to prepare the structure for its full refurbishment. Our contractors Jackson Civil Engineering Ltd. have been carefully installing stop log liners. These are essential as they will allow us to safely dewater the channels when the main refurbishment begins.

    Working with the tides on the downstream side has been particularly challenging. At low tide, the team can work on the bottom sections in dry conditions. But when the tide is higher, they need boats to install the liners.

    Upstream, significant work has taken place on the apron. Many of the timbers here are thought to have been in place since the sluice was built, making them over 250 years old! They have worn down over time as sand and gravel has passed through the sluice. These are now being replaced with new oak timbers to create a strong and even surface.

    As winter approaches, we will be pausing works at the sluice. This is a planned step to reduce flood risk and make sure the gates stay fully operational during wetter months. This approach follows best practice and was also used in the 1980's when the large timber tidal doors were refurbished. Pausing now also avoids the risk of costly delays if flooding were to force work to stop unexpectedly.

    While the sluice works pause, the contractor’s compound near Boston Rowing Club will be made smaller. The site will still be used to support other works on the Lower Witham.

    We expect to return to site in spring 2026 to continue the refurbishment. This will include replacing the gates. In the meantime, our project team will be finalising the detailed designs for these new gates, which will form the core of the main works.


    A contractor installing stop log liners on on the downstream side of Grand Sluice.




    Contractors working on the downstream side of Grand Sluice during low tide.




  • Phase One: Grand Sluice

    Preparatory works for the Grand Sluice Refurbishment have now begun.

    Our contractors, Jackson Civil Engineering Ltd., are on site and have set up a compound behind the Boston Rowing Club. This will be used as their working area. A barge is also in position on the water to transport materials from the compound to Grand Sluice and is equipped with a crane that will be used during the works.

    This summer’s work will involve installing stop log grooves in each of the three channels, preparing Grand Sluice for the main refurbishment works, which are scheduled to begin in summer 2026.

    Preparatory works for the Grand Sluice Refurbishment have now begun.

    Our contractors, Jackson Civil Engineering Ltd., are on site and have set up a compound behind the Boston Rowing Club. This will be used as their working area. A barge is also in position on the water to transport materials from the compound to Grand Sluice and is equipped with a crane that will be used during the works.

    This summer’s work will involve installing stop log grooves in each of the three channels, preparing Grand Sluice for the main refurbishment works, which are scheduled to begin in summer 2026.

    In May, the project team hosted drop in events within the community. These were held at both Fenside Community Centre and the Boston Market.

    Over 50 people attended to learn more about the preparatory works that will be taking place this summer. These events provided an opportunity for people to ask questions and express any concerns, leading to many productive discussions.

    Below, you can find answers to some of the most frequently asked questions from these events.

    Grand Sluice FAQ's

    Will these works include road closures?

    Although there are no planned road closures, there will be short durations when our contractors will need to operate traffic marshals during the delivery of materials. These will be scheduled to cause as little disruption as possible.

    Is aquatic weed flushing being considered?

    Yes. The project team are now finalising designs for tilting gate flaps, which are planned to be installed on the new vertical lift gates. These new gates will be installed as part of the main works due to start in 2026. The aim of the tilting flaps is to improve the efficiency of aquatic weed flushing without losing as much water from the system as weed flushing does now.

    We don't plan to open the sluice gates to flush weeds during our contractor's normal working hours (08:00 - 18:00) this summer. Instead, we'll coordinate with the Canal and Rivers Trust to do this in the evenings or during weekends when necessary.


    A barge equipped with a crane that will be used during the Grand Sluice refurbishment preparatory works.