FAQs

There is an existing high risk of flooding from the River Itchen to over 150 homes and 200 businesses in the Northam, St Mary’s & Chapel riverside area of Southampton. Presently there are no formal flood risk structures to protect the city from tidal flooding in this area, and where flood infrastructure does exist, it is in private ownership, offers various degrees of protection and is at varying conditions. Therefore existing quay walls, structures and land heights are not high enough to provide the level of protection needed from more frequent and severe flooding events expected in the future with climate change.

The flood risk in the scheme area varies depending on the distance from the river, the existing flood defences and the height of the land. The flood risk varies from low risk (each year this area has a chance of flooding of between 0.5% and 1%) to very high risk (each year this area has a 10% chance of flooding).

• Find out your risk of flooding by entering your postcode

The map below shows a broad outline of the flood risk in two categories.

Flood zone 2 - The extent of a flood from rivers or from the sea with up to a 0.1% (1 in 1000) chance of happening in any given year (land shown in light blue on the Flood Map).

Flood zone 3 - The extent of a flood from rivers or from the sea with greater than a 1% (1 in 100) from rivers or 0.5% (1 in 200) from the sea, chance of happening in any given year (land shown in dark blue on the Flood Map).

Climate change is resulting in global warming, a rise in temperatures across the world. Global warming is causing the ice caps to melt, causing an increase in the volume of water in the world’s oceans, resulting in higher mean sea levels. Coupled with this, the rise in global temperatures causes thermal expansion of the oceans, further increasing mean sea levels. At the west bank of the River Itchen, rising sea levels result in an increase in flood risk over the next 100 years. The existing flood risk infrastructure currently overtops on storm events with a 10% probability in any given year. The risk of flooding will only increase through time with the impact of climate change.

The scheme aims to alleviate the tidal flood risk from the River Itchen.

Although reducing flood risk from other sources of flooding, such as surface water flooding, groundwater flooding and sewer flooding are not the main aim of this project, we will ensure that flood risk from these sources is not increased, and where possible, reduced.

The scheme will be on the west bank of the tidal River Itchen between Southampton Water Activities Centre in the south and the Network Rail embankment and boardwalk in the north.

We are hoping to start construction in 2027, with a target completion by 2030.

The RIFAS will be funded through a number of funding avenues including government grants, Community Infrastructure Levy, Council funding and private investors. During the course of the scheme we will be looking for funding contributions from a number of avenues. If you would like to contribute financially to the scheme and overall regeneration of the River Itchen frontage please contact the project team at rifas@southampton.gov.uk.

We are planning to build flood risk infrastructure on the west bank of the River Itchen to reduce the risk of flooding from high tides. The exact form, alignment and finish of the flood risk infrastructure is yet to be confirmed but we will consider a range of options including new quay walls, set back walls, temporary defences and flood embankments.

Improving waterfront access is a key objective in the design of the flood risk infrastructure. Opportunities to improve connectivity to the watercourse, including walkways, promenades and slipways, will be incorporated where possible.

The main impact from this project will be during construction. Construction works are not planned to commence until 2027. This will give the project team plenty of time to plan and manage the impact on the local community.

Through the design phase we will identify the exact location of the works and access routes. In turn this will enable us to plan to reduce the impact the scheme may have on the community. The project team will keep you informed through updates on the website. If you are directly impacted by the scheme, then we aim to write to you individually to discuss this.

The RIFAS team are passionate about the environment and will be seeking to improve the environment of the River Itchen wherever possible. The team comprises of a number of organisations who have pledged to improve the environment, including:

• Southampton City Council launched the Green City Charter in 2019. It presents the Council’s vision to create a cleaner, green, healthier and more sustainable city.
• The Environment Agency has set itself the aim of becoming a net zero organisation by 2030 – ensuring that its own activities and its supply chain are taking as much carbon out of the atmosphere as it is putting into it.

The UK government’s 25-year environment plan requires all new developments to leave the environment in a better place than it was before the development began. Where potential negative impacts are identified, we will try to eliminate them wherever possible. Where not possible, mitigations or compensations will be required to limit the damage on the environment.
Improvements will consider habitat creation, habitat improvement and opportunities for supporting local schemes. The use of innovative materials and techniques will be key to supporting our goals of environmental net gain.

The scheme will be designed to avoid any increase in flood risk to the upstream, downstream or opposite frontages. As the predominant flood risk in this area is tidal flooding, increases in flood risk are not expected as a result of protecting the west bank. Flood modelling is currently being undertaken to investigate the potential for increased flood risk in these areas. If modelling identifies an additional increase in flood risk, mitigation will be put in place to reduce the impact of any increased flood risk.

In 2016 the RIFAS stalled due to a number of factors. One of the main reasons behind the scheme not progressing beyond planning permission was a loss of funding. The sources of funding at the time came under pressure to deliver other key priorities, an example of this included a need for funding in the education sector to construct a school.

The River Itchen Flood Alleviation Scheme has been developed from the Southampton Coastal Flood and Erosion Risk Management Strategy (2012) which outlines the long-term strategic approach to Southampton’s coastline. The Strategy builds on policies outlined in the North Solent SMP and helps to decide how the coastline is managed across the city of Southampton.

Southampton Coastal Flood and Erosion Risk Management Strategy identified that Southampton consists of three main independent flood cell areas for a one in 200 year flood event. Flood cells work independently due to local land levels and this means that if one flood cell experiences flooding from the sea, flooding will not flow from one flood cell into another. However, it is important to note that although flooding will not flow into a neighbouring flood cell, two cells can flood at the same time.

St Denys lies within a separate flood cell to that of St Marys, Northam and Chapel. The Strategy proposed mitigation measures for all flood cells. For St Denys it was proposed that property level flood resistance and resilience and community adaptation measures would be implemented for the highest risk properties between 2030 and 2060.

Property level resilience measures have been installed in a number of the highest risk properties in the St Denys area through the Belsize and St Denys Flood Resilience Projects. Future schemes for the area will be considered in the coming years but are dependent on funding and resources.

If you cannot find the answer to your question in this FAQ section, please email the project team at rifas@southampton.gov.uk

or write to:

Flood Risk Management
Ground Floor West Civic Centre
Civic Centre Road
Southampton
SO14 7LY