Frequently asked questions

We have experienced two historically dry summers in 2025 and 2026 causing low water levels in the River Severn from which we abstract for the Docks and the Gloucester & Sharpness Canal. This also followed an exceptionally dry summer in 2022. While pumping water into the Docks, this has also unfortunately meant a greater amount of silt than usual has also come in with the water and this silt has subsequently settled in the Docks and upper sections of the canal. This unprecedented volume of silt has necessitated the substantial increase of investment by the Trust in silt removal.

The Gloucester & Sharpness Canal’s main supply of water is from the River Severn. The water is pumped into the Docks from the river as it’s needed to operate the canal to keep boats afloat, to provide the water needed

for shipping at Sharpness Docks and to supply water for Bristol Water who extract it to provide up to half of potable water supply needed for the population of Bristol.

This campaign will focus dredging in the main basin at Gloucester Docks, the section of canal leading to Llanthony Bridge, the Llanthony Pontoons and entrance to Victoria Basin.

Currently, there is no specific time for how long it will take. It will be based on when target depths are reached and what can be achieved within the budget available. It’s expected to take place over the autumn and winter months. We’re currently significantly scaling up this campaign, and we will inform customers on timescales for completing the campaign for reopening the Docks as soon as that’s available.

The campaign commenced with the mobilisation of plant on-site early this month. Unfortunately, due to the additional volumes of silt entrained in recent weeks, over and above that already present within Gloucester Docks and the upper Gloucester & Sharpness Canal, channel depths have reduced to a greater extent than anticipated. This has meant that the first dredging team have been unable to progress as close to Gloucester. The team is currently operating just north of Romans Quay, where there was sufficient navigable depth for the tugs and hopper barges to take material south down the canal for disposal. From this location they have already dredged approximately 120-130 metres of channel and removed 11 hopper loads, equating to around 1500m³ of material. Dredging contractors are currently scaling up the size of the operation in response to increased funding with additional equipment moving into Gloucester in the coming month.

Dredging activity is constrained during certain periods of the year to protect fish spawning, migration and other environmentally sensitive activities. Operations must also comply with environmental permits and conditions designed to protect water quality. For these reasons, most dredging is undertaken during the autumn and winter period when environmental impacts are lower. As a charity, the Trust must also balance dredging expenditure with wider investment across the national canal network.

Backhoe dredging is being used for this campaign. An excavator is mounted on a floating pontoon and removes sediment using a bucket attached to the excavator arm. We are preparing a Habitats Regulations Assessment in the hope that we may also be able to deploy cutter suction dredging, which is a hydraulic dredging method that involves using a rotating cutter head to loosen silt which is then sucked up and deposited elsewhere. This would be used for a future campaign.

A lagoon field has been prepared further down the canal at Parkend. The silt will be taken via hopper barges down the canal to this location where it will then be stored before it’s spread on agricultural land. There will also be a lorry wagon system closer to Gloucester where silt will be taken away to sites where it can be recycled.

Although there are some dredging practices such as cutter suction that follows this process, a Habitats Regulations Assessment needs to be in place to allow for silt to be returned to the river. Otherwise for environmental reasons the silt cannot be put back into the river.

The current campaign has been planned on the basis that up to approximately 40,000m³ of material may need to be removed. The final quantity dredged will depend on the material encountered, access constraints, environmental restrictions and the funding available. The dredging programme is being guided by detailed hydrographic surveys and will continue until target depths are achieved or the planned scope is completed.

The first phase of the recovery dredging campaign, which began in September 2025, removed approximately 26,400m³ of silt (around 37,000 tonnes) from Gloucester Docks and the upper Gloucester & Sharpness Canal. This represented one of the largest dredging campaigns ever undertaken by the Trust and formed the first stage of the wider recovery programme following the exceptional silt ingress experienced during the summer of 2025.

The Canal & River Trust uses pump-monitoring data and sediment entrainment calculations to estimate the amount of silt entering Gloucester Docks from the River Severn. By mid-October 2026, this monitoring indicated that approximately 21,000m³ of sediment had entered the Docks during the year from Gloucester Pumps. While this was lower than the equivalent period in 2025, it remains a substantial volume and demonstrates the continuing impact that prolonged dry weather and increased pumping requirements can have on sediment accumulation within the Docks.

The amount of silt present within the Docks is not solely determined by the quantity entering in a single year. Dredging requirements are also influenced by existing sediment deposits, where the material settles, navigation requirements and the need to restore safe operating depths across a wider area of the dock system.

Maintenance dredging of the River Severn is subject to significant environmental constraints and requires appropriate assessment and permissions. The Canal & River Trust is currently working with its environmental advisers and regulators to develop the evidence base required to support future maintenance dredging proposals. Until those approvals are in place, routine maintenance dredging of the river remains restricted.

Historically the canal has been able to depend on the River Severn for its water requirements. However, with climate change forecasts predicting more extreme weather in the future, increasing the risk of drought and inadequate supply from the river (as seen this summer), then the Trust will have to consider whether other

sources are available. The Trust has already started planning for future climate scenarios, assessing risks to our water supplies and structures, but also identifying potential opportunities for ensuring the resilience of the canals. However, any consideration of other water sources for the canal would be dependent on rigorous planning and environmental assessments demonstrating no detrimental impacts to the water source, the canal or other areas such as the River Severn Special Area of Conservation (SAC).

The dredging will be to a target depth of 2.5 metres. This will enable for the vast proportion of boat traffic which use the canal to be able to navigate the Docks safely.

We operate a careful pumping schedule and programme to work around tides, which bring more debris and dirty water to the pump intakes. During the drought we’ve put restrictions in place on the usage of Gloucester Lock in order to save water being lost through the lock when vessels navigate onto the river. We’ve undertaken works to the top lock gates to make repairs to prevent leakage.

We are working with Bristol Water to manage the time periods in which we pump water from the River Severn to avoid, where possible, the height of potential silt entrainment. We have also gathered significant data from the past two years to inform and change our own pumping strategy to better ensure that we minimise the amount silt being brought into the Docks. We are looking at other measures – including those which may require additional investment – which may help reduce silt entrainment. We are aware of projects which have been suggested by stakeholders and partners which we will investigate. However, the financial pressure on us as a charity, along with environmental constraints are potential limiting factors.

The Canal & River Trust own and operate the pumps and all other related plant associated with pumping and the Docks and have responsibility for continued investment in this equipment.

The Docks is temporarily closed to boats due to the dredging activity due to low water levels and siltation. As the campaign develops, we will inform customers of the earliest opportunity to navigate through the docks.

Dredging requirements will be reviewed following completion of the current campaign and further hydrographic surveys. Whilst some level of maintenance dredging is likely to be required in future years, the scale and timing will depend on future rates of silt accumulation, available funding and the success of measures introduced to reduce silt ingress.

The Canal & River Trust is investing approximately £4 million in the current campaign. This represents a doubling of the original planned budget in response to the exceptional volume of silt that has accumulated within the Docks. This reflects not only the scale of the challenge this year but our commitment to tackling this issue and restoring the Docks to normal operation for the benefit of its many uses.

Including the allocation for this latest campaign, the Trust has invested in excess of £9 million in dredging the Docks and canal in the past five years.

The dredging is paid for by the Canal & River Trust from an allocated national dredging budget.

The Gloucester & Sharpness Canal is a vital part of regional infrastructure – for transport and commercial uses, leisure use and in the transfer of water. As part of this, the Trust has a long-standing commercial agreement with Bristol Water. This agreement is vital to support the operation of the canal and help maintain it for its other uses. The income from this agreement not only helps fund things like dredging but other operational aspects of the Docks and the canal. While this agreement is commercially confidential and so we are unable to divulge details, we are currently working positively with Bristol Water to identify future investment priorities to ensure that this agreement continues to support the various uses for and demands on the canal including increasing climate impacts.

Initially the focus is on enabling navigation for the large majority of boats that use the Docks. As progress is made an assessment will be made as to whether taller larger draught vessels will be able to return immediately, or if further dredging will be needed to welcome these vessels.

The changing climate is having an impact and we’re seeing the difference this is making on the River Severn. It’s difficult to predict what is to come in future summers, but the impact of climate change is being considered in our future management of the Docks. We will be adjusting our planning for the Docks and future dredging requirements based on the increasing number of dry years and we will seek to inform partners and stakeholders as we develop those plans.

Canal & River Trust is issuing updates to the media during different milestones of the dredging campaign. Local stakeholders and businesses receive regular updates, as well as mooring holders on the canal. We will also publish updates on our notice page on our website.

Gloucester Docks and the Gloucester & Sharpness Canal are hugely important as living heritage assets – not just for Gloucester and the region, but for the UK. The bicentenary marks an historic opportunity to recognise that

importance and look forward to what the Docks can mean for the city and the region in the future. We are working hard to reopen the Docks in time for the bicentenary celebrations, and we are working with partners, including the City Council and Gloucester Culture Trust, on events within the city to mark 200 years of this important place.

We will provide a public update on dredging progress every two months and inform boaters and other canal users of timelines in the reopening of the Docks. We will soon be convening a stakeholder Working Group to work with partners including local government and other stakeholders to consult on and inform future plans and measures to prevent reoccurrence. We are developing a web page that will provide updates on the dredging campaign.