Osney Bridge trunk mains replacement
This is a three-phase project to replace damaged water mains and reinforce Osney Bridge in Oxford.
Following the damage in 2021, we installed a temporary pipe to maintain water supply to over 22,500 customers. This currently runs above ground in the cycle lane of Botley Road, across Osney Bridge.
Structural issues with the northern footpath have caused significant delays and complications. To replace the water mains safely, we must also reinforce the footpath. This requires a lane closure on Botley Road at Osney Bridge.
Network Rail’s expansion of Oxford Station means Botley Road is closed at the rail bridge. The discovery of a Victorian inverted brick arch below the bridge area caused significant delays to the project, meaning the road closure is continuing through to October 2024. See further information on the Network Rail project.
Our original plans would have required the full closure of Osney Bridge for us to do our work. To avoid cutting off residents and businesses, we would have needed to wait until Network Rail had finished working on the road.
Background
The Osney Bridge trunk water main was damaged by a third party in June 2021. Due to the location and severity of the damage a simple repair wasn’t possible, and this led to the project being classed as a major scheme.
The project team discovered issues with the northern footpath, requiring structural and environmental surveys. To carry out the surveys, we had to close a section of the River Thames and get a flood risk assessment permit from the Environment Agency (EA). The EA then informed us that river closures at this location are only permitted between November and March.
In March 2022, we completed the required surveys. The results confirmed our concerns with the condition of the northern footpath structure. The council subsequently determined that due to our temporary watermain inadvertently protecting the northern footpath from accidental vehicle loading, no further measures were needed at that time.
This solution couldn't work long-term. So, in April 2022, it was agreed that the project would become a joint scheme between Thames Water and Oxfordshire County Council. Our aim was now to resolve the poor condition of the footpath structure, as well as the damaged water main.
The project team spent the next few months putting together an assessment report. This concluded that the footpath had never been safe for accidental vehicle loading. A far more complex solution was now needed to address the problem.
Three-phase project
Phase 1 – Enabling works
Diverting the temporary water main in the east bound cycle lane via a temporary scaffold pipe bridge over the river Thames. Full navigational use of the river Thames will be maintained once the new temporary scaffold pipe bridge is place.
Phase 2 – Main works
Replacing the damaged water trunk main and repairing and upgrading the northern footpath structure in collaboration with Oxfordshire County Council.
Phase 3 – Decommission
Removing the temporary water main installed under phase 1 and demobilising from site.
How this may affect you
Currently, our programme is as follows. This may be subject to change as a result of future site investigations, once phase 1 of the works have been completed.
From March 2024 to March 2025, we’ll need to close the following on the city-bound northside of the bridge:
- Pedestrian footpath
- Cycle lane
- Carriageway
- The Thames towpath access to Osney Bridge with a diversion via the alleyway to Abbey Road
- Closure of the River Thames for March 2024 (phase 1) and between November 2024 and March 2025 (phase 2 and 3)
As part of the carriageway lane closure, we intend to install temporary traffic lights on a timer. Once Network Rail finish their work and re-open the road under the railway bridge, we'll change these to an intelligent temporary traffic light system. This is to try and improve the traffic flow along Botley Road. It follows the traffic congestion we faced when installing the temporary water pipeline when the water main was initially damaged.
Latest update
We liaised with Network Rail to understand how the Oxford Station redevelopment could impact the project. Following these discussions, we planned to start phase 1 of the works in October 2023.
Due to discovery of a Victorian inverted brick arch below the Botley Road bridge area, the Network Rail project is significantly delayed, meaning the road closure is continuing through to October 2024. This has caused significant delay to our project.
We held a meeting with all key stakeholders, including Network Rail, Oxfordshire County Council and the Environment Agency. We proposed an alternative solution to keep the project moving forward. This is to divert the temporary water main in the east bound cycle lane of Osney Bridge across the River Thames via a temporary scaffold pipe bridge.
The alternative phase 1 solution is more complex and places greater risk on Thames Water. It also requires a flood risk assessment permit (FRAP) from the Environment Agency to allow the works to proceed.
We're now working to tight timescales due to this last-minute design change. Our aim is to start phase 1 of the project in February 2024.
Significant elements of phases 2 and 3 can only be undertaken during the River Thames closure window (November to March each year). So, this work is programmed to take place between November 2024 and March 2025.
Further updates
Members of the public are invited to a joint drop-in session between Thames Water and Network Rail on Thursday 15 February 2024 between 3pm-6pm at The West Oxford Community Centre, Botley Road, Oxford OX2 0BT.
As works progress we'll provide further updates to this webpage.