Search inSouthGlos:

Flood and Ecology

Avonmouth Severnside Enterprise Area (ASEA) Ecology Mitigation and Flood Defence Project

This project is a partnership between South Gloucestershire Council, Bristol City Council and the Environment Agency and focuses on helping to support the growth of the Avonmouth Severnside Enterprise Area and protecting the existing communities from flooding. The project will help towards unlocking the economic potential of the Enterprise Area and benefit the local community by:

  • Managing the risk of flooding to keep pace with climate change and rising sea levels.
  • Ensuring that sufficient wetland habitat for birds is created to protect the internationally important habitats and species of the Severn Estuary site.

Current status of the project

Bristol City Council and South Gloucestershire Council have both granted planning permission for 17km of improved sea defences and around 85 hectares of wetland areas for ecological mitigation:

  • You can access the planning application documents submitted to South Gloucestershire Council here. Should you need to search for it, the planning application number is: PT18/2505/R3F.
  • You can access the planning application documents submitted to Bristol City Council here. The planning application number is: 18/02847/FB.

BMM JV have been appointed by Bristol City Council, South Gloucestershire Council and the Environment Agency to undertake the detailed design of the flood defences and construction of the flood defences and wetland areas. BMM JV will undertake site investigation, survey and ecological mitigation works in the area this year, with the main construction work scheduled to start in late 2020.

Flood defence proposals mapOverview of the proposals

The proposed flood defence upgrade involves raising existing earth embankments and walls as well as innovative techniques using glass panels to ensure views out to the Severn Estuary are retained. Figure 1 provides an overview. For full details, please refer to the drawings contained within our full planning application. The new flood defences will allow for sea level rise caused by anticipated climate change to ensure flood risk is reduced for at least 60 years.

The new wetland habitat being created at Northwick and Hallen Marsh is to help protect the internationally important bird species that live on the Severn Estuary. The new wetland must be delivered to replace and expand any that is lost or disturbed by the development in the Avonmouth Severnside Enterprise Area.

The planning applications seek consent to raise the height of the flood defences between Aust and Avonmouth. The method we propose to use to do this varies from place to place (as shown on Figure 1) and includes:

  • Raising the height of existing flood banks
  • Building new, higher concrete flood walls
  • Building new, higher flood defences from steel sheet piles


More details

For full details of the proposals please refer to the planning application documents. For an overview, you may find the information below useful.

  • Our February 2020 project newsletter provides an overview of the proposals and next steps. This is available here. 
  • Within the planning application documents the Planning Statement or Chapter 2 of the Environmental Statement will give you an overview of the proposals.
  • One of the key changes we have made, since the public engagement held in Summer 2017, has been to re-think the proposed design of the flood defences at New Passage. Following discussions with residents, we have amended the design so that the proposed flood wall incorporates glass panels. This will help to reduce the visual impact of the wall and maintain views out to the estuary.
  • One of the concerns that was raised by the community was a concern about the proposed loss of poplar trees at Cake Pill. In response to these concerns we have prepared a report setting out the issues and options and this is available here.
  • Following the concerns raised by the community about the proposed loss of popular trees at Cake Pill. A petition was set up to save these trees. In response to the petition, The Environment Agency, Bristol City Council and South Gloucestershire Council have issued a statement and this is available here.

Read our frequently asked questions.

To receive updates on this project please click below to subscribe to our newsletter.

Please note that your details will be stored in line with GDPR requirements and we will use your email address only for the purpose of sending out newsletters, updates and information about this project.  You can opt out from receiving updates at any time or contact us with questions about the personal information we hold about you by emailing us.

Subscribe to our newsletter


Locate to Avonmouth Severnside

Locate to Avonmouth Severnside

With a strategic location and immense development area, Avonmouth Severnside is a prime location for businesses thinking big and operating nationally or internationally.

Read More >

Locate to Filton

Locate to Filton

A world-class area rich in aerospace technology, manufacturing and engineering. Thanks to unlocked development land, invest in your business on a reputation of excellence.

Read More >

Locate to Emersons Green

Locate to Emersons Green

An excellent new enterprise area that provides the environment, space, flexibility and support for science, research and innovation businesses to locate, flourish, grow.

Read More >