Flood Damage Economic Model
  • Details

  • Contact

  • Documents

  • Videos

Cost benefit analysis is the cornerstone of any flood defence project -a scheme must provide benefits to go ahead. FDEM streamlines this this analysis ensuring a complete, reliable and auditable assessment across the entire project area.

Recognised by the Environment agency as the most comprehensive approach to flood risk economic assessment FDEM turns a complex methodology into a simple tool based process. Complex calculations are completed at individual property level and linked to geospatial objects allowing each step to be visualised like never before.

Traditional methods require skilled economist to spend huge amounts of time doing calculations rather than applying results. FDEM automates these calculations allowing B&V economists to spend more time focusing on what the results mean and how to find better solutions


Need: The key consideration in flood Strategies is the economical appraisal of a number of flooding scenarios. For Environment Agency projects a 1 in 5 or even 1 in 8 cost benefit ratio must be delivered. The element of the assessment which delivers these sorts of returns is property.

Challenges: It is vital to consider the economics all options at the best possible level of detail and using an auditable methodology. Assessments should consider costs including capital, opex, whole life cost, operational /embedded carbon impact. As more detailed digital data becomes available and more comprehensive making use of it becomes a challenge in itself.

Solution: We have developed the Flood Damage Economics Model (FDEM). This toolbox delivers a standardised, auditable and automated approach to calculating flood economics. In doing so the tool allows subject matter experts to focus on key areas and spend time understanding and engineering solutions rather than calculating.

FDEM’s toolbox and architecture is fully scalable making it capable of supporting appraisals of small towns or entire regions or even entire nations. The toolbox delivers a consistent and repeatable assessment with every calculation stored at individual property level. As FDEM is built on top of a spatial database the entire decision process can be thematically mapped allowing the project team or public to understand flood impact like never before

Benefits: FDEM was developed with the expertise of a number of disciplines. This led to process improvements such as increased property inclusion and classification resulting in more accurate appraisal. Where a property is unknown the spatial nature of FDEM makes identification and classification simple using tools such as Google Street View.

While providing a robust audit process which better supports due diligence FDEM typically delivers over 25% efficiency saving over previous method

The toolbox also standardises and automates the time consuming and laborious tasks associated with economic assessment. Once ‘locked in’ the tools perform the same each and every time giving the user confidence and allowing economic specialists to spend time understand and interpreting the results. The inbuilt validation and reporting toolbox allow these specialists to make better engineering judgements when devising tailored solutions.

How does it make the client's life easier?

FDEM takes a complex process and makes it simple. It ensures a standard methodology is rigorously applied each time while enhancing the process and its outcomes. Economic outcomes are no longer just a spreadsheet and report. FDEM puts the outcome on a map or 3D image making them instantly understandable.



FDEM Capability Sheet
Location Analytics Capability Sheet


Key features:

FDEM is able to undertake complex economic assessments on areas large and small

Typical Buyer:

Anyone who needs to understand flood consequence, especially when cost benefit analysis is involved. The largest client to date has been the Environment Agency but Scottish Environment Protection Agency, Thames Water and State Water (Australia) have also used FDEM to inform dambreak consequence assessments. We have had interest from multiple US teams and were due to work on New York City flooding at one point. We’ve also been approached by companies who wish to buy FDEM including the Department of the Environment Northern Ireland. A decision was taken not to sell FDEM and only offer it as part of a service contract. Due to existing framework agreements the DOENI were unable to take this any further

The Multi Coloured Manual on which FDEM is based is a UK research project but recognised globally as a basis on which to determine flood economics. State Water used a predecessor called Flair but we happy to migrate to MCM once the benefits were detailed

Pain points or what to listen for:

Is a project or business case not stacking up based on the cost benefit analysis of flood consequence? FDEM does tend to find more damages against traditional excel approaches

Is investment required based on trigger consequence levels? Black & Veatch undertook a Dam consequence assessment on the Hume Dam for State Water. They had to invest an additional $200m if the dam was shown to risk 1,000 people’s lives during a failure. Previous studies had generalised widely as it was thought too big an area to assess in detail. FDEM brought property level analysis of over 100,000 properties. Fully auditable and commended by the author of Australian Dam Break guidance FDEM shown that applied properly the risk was actually significantly lower than previously estimated.

Are the flood economics on a project particularly complicated? ARUP and Halcrow have employed Black & Veatch to complete the economic elements of their projects as they recognised FDEMs benefits to them. John Chaterton, one of the authors the guidance on flood economics has commended FDEM and used it to validate his results on his contracting projects.


Flood risk, economics, cost benefit analysis, flood visualisation