Aegaea hold all the flood models and breach data on our own systems, so there’s no delay in your application while waiting for data - we can process and write your FRA within 5 working days! That’s time saving and cost saving across London.
Learn more about how flood risk affects planning in London
We have summarized the useful and key information required to better understand how flood risk can impact your London development and the importance of a FRA for Planning.
Different Types of Flood Risk in London
The City of London has been constructed on a large Flood Plain. As such the vast majority of it is within a Flood Zone. Central London in particular is affected by multiple sources of flooding. Thankfully, it’s also protected to a 1 in 1000-year standard of protection by the Thames Barrier. Without it, London would be at a much more significant risk of flooding.
The Environment Agency map for planning demonstrates only the flood risk from rivers and seas without the presence of defences. This is why Central London, such as the London Borough of Southwark for example, is shown to be within a Flood Zone. Due to its urban characteristics, London is greatly affected by surface water flooding and sewer flooding. However, these data sets cannot be accessed by the Environment Agency Flood Map for Planning.
There’s also the question of residual risk should the defences fail. Although this is considered to be a highly unlikely scenario, much of London is still assessed based on this risk. However small the possibility, the results of such an event would be devastating to much of the area.
When assessing flood risk throughout London, our team will review multiple sources of flooding, as well as this residual risk (commonly referred to as Breach), to ensure every risk can be mitigated to gain planning.
London also contains many boroughs that are considered Critical Drainage Areas. This is where surface water is unable to drain at an appropriate rate, causing further flooding. These areas always require a Flood Risk Assessment no matter the development.
Across London, the severity and extent of each source of flooding vary. It is therefore important for the success of a project to understand what flood zone your site is located in and whether it is affected by other sources of flooding. This could impact the design, timeframes, and mitigation measures required to make the development acceptable for planning. If each flood risk source has not been appropriately reviewed, it is likely to be rejected at Planning by the Environment Agency or Local Planning Authority.
There are certain developments that are permitted within the London Flood Zones that don’t need an exception test. However, if it is necessary and the development doesn’t pass the exception test, it’s likely to be rejected at the planning stage.
Find out more about the exception test here.
Unlocking Development In London
The City of London has been constructed on a large floodplain. As such, the vast majority of it is within a Flood Zone.
Central London, in particular, is affected by multiple sources of flooding.
Thankfully, the Thames Barrier protects it to a 1 in 1000-year standard up to the year 2100.
Without it, London would be at a much greater risk of flooding.
Isn’t The Flood Map For Planning Enough?
No! The Environment Agency flood map for planning only shows the flood risk from rivers and seas without the presence of defences.
London policy has requirements on breach analysis, surface water, residual risk and critical drainage areas!
The data sets that inform on this risk are not immediately accessible through the Environment Agency (though they can be requests).
When assessing flood risk throughout London, our team will review large amounts of data to give you a clear picture of risk.
Read more about why Flood Risk Assessments in London differ from other parts of the UK.
Surface Water
Due to its urban characteristics, London is greatly affected by surface water and sewer flooding.
London also contains many boroughs that are considered Critical Drainage Areas.
These are areas where surface water is unable to drain at an appropriate rate, causing further flooding. These areas always require a Flood Risk Assessment, no matter the development.
Residual Risk (Breach)
What happens if defences fail?
Though this is considered to be a highly unlikely scenario, much of London is still assessed based on the question, “What would happen if?”
However small the possibility, the results of such an event would be devastating to much of the area.
What Sets Aegaea Apart?
Across London, the severity and extent of each source of flooding vary.
It is, therefore, important for the success of a project to understand what flood zone your site is located in and whether it is affected by other sources of flooding.
This could impact the design, timeframes, and mitigation measures required to make the development acceptable for planning.
If each flood risk source has not been appropriately reviewed, the Environment Agency or Local Planning Authority will likely reject it at Planning.
We’ve got in-depth knowledge of London Borough Policy and how it impacts your plans.
