King's Lynn and West Norfolk settlements SWMP

A large number of intense rainfall events fell across King’s Lynn and West Norfolk between late May and late November 2014.

Reports received from affected residents and businesses highlight rainfall events on 27 June, 10 July, 14 July, 8-9 August and 21 and 28 November 2014. These led to the internal flooding of 42 properties. Of these 42 properties, 36 (86%) were impacted by the 8-9 August 2014 rainfall event. The parishes most affected were Upwell & Outwell. View the Flood Investigation Report.

Norfolk County Council (NCC) and the Borough Council of King’s Lynn and West Norfolk have been working with the Environment Agency, Anglian Water, Internal Drainage Boards and other organisations to produce a Surface Water Management Plan (SWMP) that covers King’s Lynn and other priority settlements in West Norfolk.


Stage 1 of the project involved bringing together a steering group to manage the project, gathering all available and relevant data at that time and starting engagement with local resilience groups, parishes and Councillors.

The SWMP initially addressed 17 localities that had suffered surface water flooding or carry a high surface water flood risk; the later work focused on producing surface water flood risk mapping for the four highest priority areas: King’s Lynn, Downham Market, Heacham and Snettisham.

The further Ordinary Watercourse Study assessed both the surface run-off flood risk and the flood risk from the Gaywood River and Pierrepoint Drain catchments in King’s Lynn.

The predicted consequences of surface water flooding to property, business and infrastructure and those areas identified to be at more significant risk have been identified as Critical Drainage Catchments (CDCs).

CDCs form the main focus for partner engagement, detailed analysis and potential implementation of flood protection schemes.

The detailed work undertaken during Stage 2 of the SWMP and further studies into the Ordinary Watercourses have led to the production of customised surface water maps and a range of mitigation options intended to reduce flood risk and the impact of surface water flooding.

Use of surface water flood mapping within the reports

Note that the maps within the Kings Lynn and Area Settlements Surface Water Management Plan and the Kings Lynn Ordinary Watercourses Study show the predicted likelihood of surface water flooding (this includes flooding from sewers, drains, small watercourses and ditches that occur in extreme rainfall events) for defined areas.  Due to the coarse nature of the source data used, these are not detailed enough to account for precise addresses.

Individual properties therefore may not always face the same chance of flooding as the areas that surround them. There may also be particular occasions when flooding occurs and the observed pattern of flooding does not in reality match the predicted patterns indicated on these maps.

To the extent permitted by law Norfolk County Council ("We" or "we") will not be liable if the maps by their nature are not as accurate or complete as might be desired and we make no representation or warranty, express or implied, that the maps will be accurate, complete or up to date.

We have taken reasonable measures to ensure that the maps reflect all the data we possess and in good faith have applied our knowledge to create reasonable conclusions.

It is essential that anyone using these maps fully understands the complexity of the data utilised in production of the maps, is aware of the limitations and does not use the maps in isolation.

Users of these maps should refer to Appendix A of Kings Lynn & Area Settlements Surface Water Management Plan Report for a complete description of the limitations and accuracy of the flood or hazard extents shown. These maps provide strategic overview of surface water flood risk and may be subject to further analysis in the future.

All intellectual property rights in the data and information on this website are owned by Norfolk County Council or are licensed from other third party data providers.

Stage 1 of the project was completed during 2011.

King's Lynn and West Norfolk Settlements SWMP: Stage 2 report, appendices and maps

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