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Surface water flooding

Information about surface water flooding and our management plans

What is surface water flooding?

Surface water flooding (also known as pluvial flooding) occurs when the amount of rainfall exceeds the capacity of a drainage system, watercourse or the ground to absorb the water. Surface water flooding typically results in water pooling on impermeable surfaces (such as pavements and roads) or flowing over the ground and is typically caused by heavy or prolonged rainfall.

The risk of surface water flooding is typically greatest during summer but can occur at any time of the year. Surface water flooding can occur quickly, meaning it is difficult to predict when and where it will occur.

Who manages flood risk from surface water flooding?

Norfolk County Council as the Lead Local Flood Authority is responsible for investigating the causes and consequences of surface water flooding in Norfolk. They do this through surface water management plans to identify areas which could be at risk from surface water flooding. You can find out more about these plans on their website.

In 2021, the Norfolk Strategic Flood Alliance (known as the NSFA) was established following significant surface water flooding in December 2020. The NSFA aims to bring together all agencies and partners who are involved in managing flood risk across Norfolk to work in collaboration to manage surface water flooding. You can find out more about the NSFA here.

Surface water flooding policy

How we manage flooding from surface water in West Norfolk is governed by various acts and policies which we follow.

Flood and Water Management Act (2010)

Following extensive flooding during the summer of 2007, an independent review of the floods known as the Pitt Review was undertaken to determine what could have been done differently. One of the key outcomes of this review was the development of The Flood and Water Management Act (2010).

The Flood and Water Management Act (2010) was introduced to improve flood risk management and to ensure security of water supplies in England and Wales. The Act established Lead Local Flood Authorities (LLFAs) who have responsibility for managing local flood risk. For Norfolk, the LLFA is Norfolk County Council.

King’s Lynn & West Norfolk Settlements Surface Water Management Plan (2012)

In 2012 a surface water management plan for King’s Lynn and West Norfolk settlements was published. The plan was produced by Norfolk County Council and the Borough Council alongside input from the Environment Agency, Anglian Water and Internal Drainage Boards.

The plan was split into four stages:

  1. Stage 1 – Preparation
  2. Stage 2 – Risk Assessment
  3. Stage 3 – Options Assessment
  4. Stage 4 – Implementation and Review

The SWMP initially addressed 17 locations across West Norfolk which had experienced historic surface water. Later work of the SWMP then focused on producing surface water flood risk mapping for four priority areas identified: King’s Lynn, Downham Market, Heacham and Snettisham.

You can find out more about the surface water management plan and read the reports produced on the Norfolk County Council website.

Ordinary Watercourse Study (2015)

Following the 2012 surface water management plan, in 2015 an ordinary watercourses study for King’s Lynn and West Norfolk settlements was published. This assessed both the surface run-off flood risk and flood risk from the Gaywood River and Pierpoint Drain catchments in King’s Lynn.

You can find out more about the Ordinary Watercourse study and read the reports produced on the Norfolk County Council website.

Strategic Flood Risk Assessment (2017-2018)

The Borough Council has a strategic flood risk assessment to assess the risk of flooding from all sources for planning purposes. For further information, please see our flood risk assessment planning pages.

Reporting surface water flooding

In an emergency

In an emergency, if people or property are in immediate danger & require immediate assistance call the Norfolk Fire & Rescue service on 999.

Non-emergency situations

To report flooding following a flood event, call the Norfolk Flood Hotline on 0344 800 8013 or visit the Norfolk County Council website to report flooding online at

Further information and guidance

The NSFA has produced guidance on the rights and responsibilities for watercourse maintenance if you live on, own or lease land next to a watercourse. You can view this guidance on the Norfolk County Council’s website here.