Flood risk mitigation: preparing a response plan

Major weather events have become a regular feature on our daily news including periods of prolonged rainfall resulting in flood events. Flooding can cause widespread damage and disruption to homes, businesses, and national infrastructure, potentially resulting in costly restoration and business interruption. The continued effects of climate change mean extreme weather events are projected to increase in severity and likelihood.   

Preparation before a flood event is key to help avoid or minimise the impact of a flood loss.   

Common types of flood events 

River flooding 

Referred to as fluvial flooding, this occurs when a river or other watercourse overflows onto the surrounding land. This is typically caused by prolonged heavy rain and can be exacerbated by snowmelt. 

Surface water flooding 

Referred to as pluvial flooding, this occurs when heavy rainfall overwhelms the drainage system within an area. This could occur in any area, not necessarily close to a local water body. Flash flooding can occur from heavy rainfall, particularly on elevated terrain, creating a strong force of water and the risk of moving debris. 

Coastal flooding 

Typically resulting from a combination of strong winds and high tides.   

 Other causes of flooding can include sewers (where they are overwhelmed or become blocked), high levels of groundwater, and the failure of a dam or retaining wall.

Assessing the risk of flood

Consider the risk of flooding at your premises including any previous loss events, results from flood modelling tools, any installed protection systems (including their reliability), and features within local environment. For example, have there been any changes in or around your premises, such as new buildings or paved areas which could increase the risk of flooding? Existing drainage systems may not be designed for potential future rainfall events, or could be compromised by debris or other blockages.

Flood mapping tools are available to provide an indication of the extent and likelihood of flooding.  However, these should not be relied upon to give a definitive answer. When using such tools, the likelihood of flooding is typically expressed as a return period for a flood event, such as a 1 in 100-year flood. This is a prediction that in a 1 in 100-year flood event, the area will be flooded. However, it should not be interpreted as if only one flood will occur every 100 years.

Mitigating the risk of flood 

To help mitigate the risk of flood to your premises consider: 

  • The risk of a flood event occurring (severity and likelihood) 

  • The vulnerability of the premises to flooding 

  • Flood prevention, control, and response measures to mitigate the risk 

Simple measures to help reduce losses in the event of a flood include subscribing to a flood alert scheme, placing vulnerable stock or equipment at higher level, and ensuring a robust business continuity plan is in place.

Where possible, suitable measures to reduce flood risk should be already incorporated during building and construction. This might include increasing floor levels or locating vulnerable equipment above anticipated flood levels. In areas at higher risk of flooding, property owners should consider measures such as flood resistant construction materials and locating utility points at a higher level. Ensure key information needed for business recovery such as plans and specifications is backed-up.

Locations within a flood zone should conduct a basic flood assessment and response plan. Locations at higher risk of flooding or that are more vulnerable should conduct a more detailed assessment and prepare a robust flood response plan. The flood response plan should be reviewed and tested regularly.

Preparing a flood response plan 

Flood risk 

Consider factors such as: 

– The source of potential flooding 

– How early warning of the flood can be provided 

– Potential warning times (the time available to implement the flood response) 

– The likely depth of water and which areas might flood first, including basements and potential escape routes from the site

– Potential water entry points such as doorways, wall vents, drains and toilets 

Flood vulnerability 

Consider factors such as: 

– The impact of flood water to the building, equipment, and stock. Flood events can introduce silt, sewage, and debris into a building. Mould and corrosion can quickly follow after a flood event 

– How long it might take to restore the operation, along with the estimated costs to the business 

Flood prevention 

Consider factors such as: 

– Ensuring building and surface water drains are clear 

– Ensure nearby streams and water courses are kept clear 

– Where practicable, ensure nearby flood defences are maintained and operational 

Flood control 

Consider factors such as: 

– Designing or updating buildings and facilities to ensure critical equipment is located outside of areas at risk of flooding 

– Providing flood barriers to prevent ingress of flood water. Water is very pervasive, so it is important to consider all possible routes of ingress, not just doorways 

– Relocating critical equipment and stock above anticipated flood levels during periods of increased flood risk 

– Providing sump and pump systems to remove flood water 

Flood response 

Consider factors such as: 

– Ensuring reliable sources of information to provide early warning of potential flooding 

– How and when the flood response plan is activated 

– What actions should be taken and when. This might include relocating equipment and stock, installing flood barriers, driving vehicles off-site, isolation of power or other utilities, securing the site and evacuation of personnel 

– Staff roles and responsibilities to implement the plan 

– The approach to clean the site following a flood event 

– Retaining contractors and suppliers to provide resources before or following a flood event. Such resources might include generators, pumps, sandbags, plant equipment, cleaning equipment and dehumidifiers. Some companies subscribe to a disaster recovery company to provide support following a loss 

– The flood response plan should be documented, reviewed, and exercised regularly, with training provided where necessary 


Flood events continue to cause losses within commercial properties, but effective preparation can help minimise losses in the event a flood occurs. For further guidance or advice consult your broker and insurer.   

For further information, please visit the Lockton Risk Control page (opens a new window), or contact:  

Rupert McLean, Client Advocate Hospitality Division 

T: +44 (0) 772 565 1142 

E: rupert.mclean@lockton.com  


Mark Hallworth, Risk Management Executive  

T: +44 (0) 744 323 2263 

E: mark.hallworth@lockton.com  

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Flood risk mitigation: preparing a response plan

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