Oxford Flood Alleviation Scheme (OFAS) Approved

Oxford has flooded repeatedly from the River Thames, in 2003, in 2007, and again over the winter of 2013–14, closing roads and the railway and forcing people out of their homes. OFAS is the long-term answer to that, and it has moved a long way since it was first proposed. This article explains what the scheme involves, what it will cost and save, and exactly where it stands in mid-2026.

What is the Oxford Flood Alleviation Scheme?

The Oxford Flood Alleviation Scheme is a major flood defence and habitat project for the western edge of Oxford. OFAS stands for Oxford Flood Alleviation Scheme. Rather than relying on hard walls and embankments alone, it creates a new watercourse and a wider, lower floodplain that gives the Thames somewhere to spread during a flood, away from homes, roads and the railway.

The Environment Agency is leading the work alongside a partnership of local councils, utilities and community groups. The scheme has been in development for more than a decade, shaped through repeated consultation, an independent planning process and a Compulsory Purchase Order inquiry. The version now going ahead is the product of that long review.

Where will the new flood channel run?

The centrepiece is a new five-kilometre stream and two-stage channel to the west of Oxford. It begins just north of Botley Road, runs south through the existing floodplain, and rejoins the River Thames south of the A423 near Kennington. Most of the route crosses farmland and floodplain meadow.

During high flows the channel carries excess water past the city, easing pressure on the existing river network through Oxford. The Environment Agency’s route map and project information show how the channel sits within the landscape and how its width changes along the way.

How much will OFAS cost, and what will it save?

The scheme is budgeted at £176 million. Over its lifetime, the Environment Agency estimates it will prevent more than £1.8 billion of flood damage and disruption, protecting not only property but the local economy, which loses heavily every time Oxford’s roads and railway close.

OFAS forms part of a wider national push on flood defence. The government has committed record investment in flood and coastal schemes over the coming years, which Unda has covered separately.

A nature-based design built around wetland and meadow

OFAS is as much an environmental project as an engineering one. The works will create more than 36 hectares of new habitat, including over 20 hectares of wetland and around 16 hectares of restored floodplain meadow, along with wildflower seeding, backwaters, scrapes and ponds to support wildlife.

This is natural flood management in practice: using a restored, working floodplain to slow and hold water rather than rushing it downstream in a concrete culvert. Once finished, the channel and its meadows will be open to the public and linked into Oxford’s green spaces, doubling as somewhere to walk and cycle.

Protecting Oxford’s homes, railways and roads

Beyond the 1,600-plus properties it defends, OFAS is designed to keep Oxford moving during a flood. The scheme protects:

• the Great Western main line railway between Oxford and Didcot
• key routes including Botley Road and Abingdon Road
• utilities such as water, power and broadband

Past floods have done more than damage buildings. They have cut off Botley and Abingdon Roads, closed the railway and brought the city to a standstill, the kind of disruption many residents remember from 2007 and the winter of 2013–14. Reducing that risk sits at the centre of the scheme’s economic case.

Where the scheme stands in mid-2026

OFAS has cleared its main hurdles and is moving towards construction. As of mid-2026 the position is:

The Environment Agency expects construction to start in late 2026 and to take around five years. A Stakeholder Advisory Group of local residents is being set up, and the appointed contractor will name a Community Liaison Officer as the point of contact once work begins.

Who is delivering OFAS?

The Environment Agency leads OFAS in partnership with nine other organisations: Oxfordshire County Council, Oxford City Council, Vale of White Horse District Council, Thames Water, the Thames Regional Flood and Coastal Committee, the Oxford Flood Alliance, Enterprise Oxford, the University of Oxford and National Highways. The full scheme partnership and policy detail is published by the Environment Agency on gov.uk.

Support has been broad. Robbie Williams, the scheme’s Project Director, called the funding decision “a major step forward”, adding:

Dr David Prout of the University of Oxford said the scheme would “help ensure a prosperous, sustainable future for the city”, while Simon Collings of the Oxford Flood Alliance described it as “the best option for Oxford, its communities, its economy and biodiversity.”

What OFAS means for flood risk and planning in Oxford

A scheme of this scale changes the flood risk picture for much of western Oxford, but it does not remove risk entirely. The Environment Agency has been clear that some properties will still face a residual chance of flooding, and household-level resilience measures will still matter in the most extreme events.

For anyone buying, developing or insuring property in and around the Oxford floodplain, the practical question is how the scheme affects a specific site, which depends on its location, ground levels and flood zone. Until OFAS is built and the official flood maps are updated to reflect it, planning applications are still assessed against current flood risk data, as our latest EA Flood Map for Planning update explains.

Frequently asked questions

Planning a development in or near Oxford’s floodplain?