Policy paper

Oxford Flood Scheme

Updated 22 February 2021

The Environment Agency is working in partnership on a major new scheme to reduce flood risk in Oxford. The Oxford Flood Alleviation Scheme will cost around £150 million and is one of the biggest flood schemes in the country. It will reduce flood risk to homes, businesses, services and major transport routes into the city.

Oxford has the second fastest growing economy of all UK cities. The scheme will keep Oxford open for business and keep the economy thriving. It will also bring environmental benefits to the area in addition to reduced flood risk.

The scheme partners are:

• Environment Agency
• Oxfordshire County Council
• Oxford City Council
• Vale of White Horse District Council
• Thames Water
• Thames Regional Flood and Coastal Committee
• Oxford Flood Alliance
• Oxfordshire Local Enterprise Partnership
• University of Oxford
• Highways England

Why Oxford needs a flood scheme

Oxford has a long history of flooding. Significant floods in recent decades have caused damage to homes and businesses and closed the main railway line and major roads.

The Environment Agency maintains rivers and streams in and around Oxford. This work reduces the risk from smaller floods. Significant flooding cannot be reduced by maintenance alone.

Climate change is happening now and the UK government declared a climate emergency in 2019. We have seen the devastating effects of flooding across the country this winter and climate change is expected to cause more frequent and more severe floods. The Oxford Flood Alleviation Scheme is designed to manage flood risk in Oxford over the next 100 years.

How the scheme will work

The Oxford Flood Alleviation Scheme will create a new stream with wetland wildlife corridor, running through the existing floodplain to the west of Oxford. This will create more space for floodwater away from built-up areas, reducing flood risk in Oxford and surrounding areas for many decades to come.

The scheme will be approximately 5km long. It begins north of Botley Road and ends south of the A423 near Kennington, where the new stream joins the River Thames.

Most of this area is farmland and flood meadow. We have designed the scheme to be as natural as possible in appearance and to blend into the surrounding fields. Material will be dug out to create:

• a new stream which will always carry water - this will look and behave like a natural river
• a gently sloping floodplain of wetland habitat, grazing meadow and wildflowers running alongside the new stream - most of the time this will be dry

When water levels in the River Thames are high, flood water will overtop the new stream and start to fill the lowered wetland around it. This will ensure that water flows away from built-up areas. This reduces flood risk to houses, businesses and infrastructure, while fitting with the existing landscape. The design also brings additional environmental benefits to the local area beyond reduced flood risk.

In some areas new structures are needed to complement the new stream, for example:

• new bridges will be built where footpaths cross the new stream
• culverts and bridges in the south of the scheme to allow water to pass under main roads
• earth embankments and flood walls in places where homes would otherwise still flood

A map showing the route of Oxford Flood Alleviation Scheme. It begins north of Botley Road and ends south of the A423 near Kennington, where it joins the River Thames.

Flood risk to properties downstream will not increase as a result of the scheme. Flood risk will remain the same as it is now.

In December 2017, Vale of White Horse District Council commissioned an additional review of the downstream impact modelling. This confirmed that the scheme will not increase flood risk to downstream properties.

When river levels are high, the scheme will divert some flood water across the undeveloped floodplain and away from properties. The same amount of water that enters the scheme will return to the River Thames at Kennington.

How the Oxford Flood Alleviation Scheme will benefit Oxford

The scheme will benefit everyone who lives, works in or visits Oxford. The scheme is designed to reduce risk from the size of a flood not seen in Oxford since 1947. This means it’s designed to cope with floods larger than all those Oxford has experienced in recent decades.

The Environment Agency and partners worked around the clock to protect Oxford from flooding this winter, but it could have been much worse. With climate change floods are expected to become more frequent and severe. It is only a matter of time before a major flood happens again.

Homes and businesses

The scheme will reduce flood risk to all homes and businesses in Oxford currently at risk of flooding from the River Thames. The scheme will provide peace of mind to residents who are currently at risk of flooding.

Infrastructure

Flood risk to vital transport links, including the railway and the Botley and Abingdon roads, will be reduced. There will be fewer flood related electricity, telephone and internet disruptions. Many properties will be less likely to experience sewer flooding.

Environment

The scheme will create over 20 hectares of new wetland habitat. It will work with the natural floodplain and blend with the existing environment. The lowered ground alongside the new stream will consist of wetland habitat, grazing meadow and be seeded with wildflowers. It will be landscaped to include around 4 hectares of backwaters, scrapes and ponds. These will be a variety of depths and sizes to encourage biodiversity of wetland and aquatic wildlife. The new stream and its associated habitat will link up existing wetland sites. This will create a wildlife corridor to the west of Oxford, further increasing biodiversity.

We are working closely with local wildlife groups on an ambitious environmental vision for the scheme. This will ensure the scheme is maintained in the long term and provides a true green legacy to the area.

Environmental Vision

The Environment Agency has a plan to ensure that the scheme area is properly cared for and maintained after it is in place. This plan is known as the ‘Environmental Vision’.

The Environmental Vision will ensure the habitats, wildlife and environmental features of the scheme area are properly maintained and continue to improve in the long term. It will ensure the scheme is a valued asset for the local community and the environment for generations to come.

As part of the vision, the Environment Agency has formed a new collaboration with the environmental charity the Earth Trust. We will be working with the Earth Trust on our plan for the long term environmental benefits of the scheme. This work will establish the best approach to ensure the scheme improves the local environment over time.

Once we near construction of the scheme, we will appoint an external environmental partner. The partner will be responsible for:

• habitat management and enhancement
• maintaining long term engagement with local communities

They will ensure the Oxford Flood Alleviation Scheme delivers a long term green legacy for many decades to come.

What stage is the scheme at?

In 2019 Oxfordshire County Council found that the A423 Kennington railway bridge (Southern by-pass), in the south of the proposed scheme area, needed to be replaced. Floodwater from the scheme will need to pass underneath the A423 bridge.

Now that the bridge needs replacing it can be designed from the outset to take this into account. Replacement of the bridge alongside the scheme provides an opportunity to design and build the bridge and the scheme together reducing disruption and ensuring the best use of public money.

This will require changes to the planning and compulsory purchase order applications for the Oxford Flood Alleviation Scheme. These had been made in 2018. New applications will be made to incorporate the necessary changes.

The Oxford Flood Alleviation Scheme has been shown to be the best long term solution for Oxford. The Environment Agency and all the scheme partners remain fully committed to delivering the scheme.

The scheme design will remain fundamentally the same. With climate change, flooding will become more frequent and severe and this is the best option to reduce flooding in Oxford when a major flood occurs in the future.

How this partnership scheme is being funded

This ambitious project is made possible through central government funding and local contributions. A record £66.5 million has been raised by partners. These include:

• Oxfordshire County Council
• Oxfordshire Local Enterprise Partnership
• Thames Regional Flood and Coastal Committee
• Oxford City Council
• Thames Water
• Highways England

Find out more

To sign up to newsletters from the Oxford scheme please email: oxfordscheme@environment-agency.gov.uk.

To keep up to date with the project you can like the Oxford scheme’s Facebook page and follow them on Twitter.

Oxfordshire County Council Flood Toolkit - this site provides valuable advice on how to prepare for a flood and what you should do during a flood. You can also download our previous newsletters from here.

The Oxford Flood Alliance is a community group and scheme partner. They campaign to reduce and protect people from flooding in the Oxford area. The site provides a community perspective on the damages of flooding and the benefits of the Oxford Flood Alleviation Scheme.