Developing the new Fluvial Modelling Standards (FMS)

Location: UK                                                                                               Client: Environment Agency

We were commissioned by the Environment Agency in autumn 2020 to develop the Fluvial Modelling Standards (FMS). The purpose of this project was to provide a single set of guidelines for modelling practitioners and reviewers, increasing consistency across the flood modelling industry, and to develop a model review tool.


The challenge presented was to answer the question of “how good is good enough” in the world of fluvial non-real time hydraulic modelling. New reporting had to be accessible and comprise technical advice backed up by published literature. The review tool had to use a model grading system and be suitably streamlined to be applied on the Environment Agency’s back catalogue of models.


A staged approach was adopted. Initially a literature review was developed, forming an appraisal of highly relevant documents from the Flood and Coastal Risk Management community, including the Flood Estimation Guidelines, Fluvial Design Guide, National Standard Technical Specifications for Surveying Services and the National Planning Policy Framework, to name a few. The review enabled the project team to state the current level of knowledge.

Following review of this, the new Standards were written in the following format:

  • Source: methods to estimate the source of water entering a fluvial or sewer system
  • Pathway: approaches to represent river channels, sewer networks and floodplains
  • Receptor: approach to represent flood receptors (buildings and infrastructure)
  • Modelling approaches: covering all aspects of hydraulic modelling not captuted in the above (e.g. calibration, parametrisation, software choice)

The document was reviewed by the Environment Agency project teams and external stakeholders including other NGSA framework consultants. Comments were received and discussed at a series of workshops with all reviewers before a final version was produced and approved. Once supplied to the Environment Agency, a further three months were utilised to transform the technical version into a more accessible and inclusive one published on The technical guidance and associated documents remains available on request from the Environment Agency and is recommended for all modelling practitioners.

Accompanying the new FMS is a Fluvial Model Assessment Tool (FMAT). This Excel based tool compliments the Environment Agency’s current set of tools used for quality assurance of models. Whilst the Non-Real Time Review Spreadsheet (NRTS) is used to complete technical model reviews, the new tool enables non-technical reviewers to assess model quality and condition of hydraulic models.  This is achieved via a series of questions, each related to a different section of the Standards document. The tool is based on the following scoring criteria.

Fluvial Modelling Standards

Upon completion the tool was tested on 12 existing hydraulic models, ranging in size, type and complexity. The conclusions from this process were presented in the accompanying Fluvial Model Assessment Tool Guidance (FMATG) document.

Want to know more?

Email Kevin Haseldine for more information about this project. The accessible version of the Fluvial Modelling Standards can be found here:

The Fluvial Model Assessment Tool and the tool guidance can be requested by emailing the Environment Agency enquiries service.

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