Frequently Asked Questions

We have complied a list of frequently asked questions relating to the broad ranging water consultancy services that we offer.
Please do not hesitate to contact us on 01824 702220 with any other questions relating to your individual requirements.  Thank you.

What is a Flood Risk Assessment?

A flood risk assessment has become a key part of local and national planning policy when determining a sites suitability for development and /or redevelopment.
Regionally the specific requirements can vary but typically the location, size and nature of the development drives the requirement to complete a Flood Risk Assessment (England and Scotland) or a Flood Consequence Assessment (Wales).

See Flood Risk Assessment to Support Planning Applications

Why do I need a Flood Risk Assessment?

A Flood Risk Assessment is typically required when any of the following applies:

  1. The site is over 1ha
  2. Can be classed as a major development (see question below)
  3. Located in Flood Zone 2 or 3
  4. Drainage area is classed as critical

Similar guidance can also be applied when considering the need for a drainage strategy. However this is Council specific, so it is always best to check! Call our team on 01824 702220

How much does a Flood Risk Assessment Cost?

Estimated costs & timescales for flood risk assessment (and hydraulic modelling if required) can vary widely. Services start from £600 + VAT, and our full price list of Flood Risk Assessment services can be found by visiting our web shop.

It is important that you have confidence that the findings from our flood study are accepted first time.

We appreciate that every client has different priorities and every site has different requirements, and we recommend discussing your specific requirements with our team to ensure you are choosing the correct service.

Can I check the requirement for a Flood Risk Assessment myself?

Check the Environment Agency flood map for planning. Is the site in a flood zone?

  • Check your Lead Local Flood Authority (LLFA) Strategic Flood Risk Assessment (SFRA). Is your site in a critical drainage area?

Check the development. Is the site over a hectare? Is the development a major or minor development?

Major Development

  • 10+ dwellings / over half a hectare / building(s) exceeds 1000m²
  • Office / light industrial – 1000+ m² / 1+ hectare
  • General industrial – 1000+ m² / 1+ hectare
  • Retail – 1000+ m²/ 1+ hectare
  • Gypsy/traveller site – 10+ pitches
  • Site area exceeds 1 hectare

Minor Development

  • 1-9 dwellings (unless floorspace exceeds 1000m² / under half a hectare
  • Office / light industrial – up to 999 m²/ under 1 hectare
  • General industrial – up to 999 m²/ under 1 Hectare
  • Retail – up to 999 m²/ under 1 hectare
  • Gypsy/traveller site – 0-9 pitches

Can I contact the Environment Agency (England), NRW (Wales) / SEPA (Scotland) or Lead Local Flood Authority to help?

Yes – Below are 2 example responses from the Environment Agency (England) that outline the requirement for your specific development.

If you’ve received similar correspondence please contact us to discuss how we can help.

Environment Agency Example Responses

Flood Risk
Our maps show the site lies partly in flood zones 2 and 3, the high probability zone.

The proposal is for a residential development, which is considered to be a ‘more vulnerable’ land use in Table 2: Flood Risk Vulnerability Classification of the Planning Practice Guidance: Flood Risk and Coastal Change. It is therefore necessary for the application to pass the Sequential and Exception Tests and to be supported by a site-specific flood risk assessment (FRA), which can demonstrate that the ‘development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall’.

We have included a factsheet with our response which sets out the minimum requirements for the FRA and further guidance on completing an FRA is available on our website. You will also need to consider how the new climate change allowances will affect the flood risk to your site.

The application site lies within Flood Zone 3 and is effected by both fluvial and tidal sources. Footnote 20 paragraph 103 of the National Planning Policy Framework (NPPF) requires applicants for planning permission to submit a Flood Risk Assessment (FRA) when development is proposed in such locations.

Your FRA should include (but not necessarily be limited to) the following:
– Identification of the Flood Zone and vulnerability classification in accordance with Table 2 of the National Planning Practice Guidance, Flood Risk and Coastal Change (section 25)

We have already carried out an FRA (done by others) but are now being asked to provide further information? E.g. modelling

In certain areas the LLFA, EA, SEPA or NRW may not hold sufficient information for your site to inform their decision on flood risk, flood sources and flood hazards.

Waterco can support your FRA in-house with hydrology assessments and detailed hydraulic modelling.

See our other services for more information or call our team on 01824 702220

Why do I need a Drainage Strategy?

Also referred to as a SuDS report, a Sustainable Drainage System (SuDS) drainage strategy or a surface water drainage strategy.

A Drainage Strategy is typically required when any of the following applies:

  • The site is over 1ha
  • Can be classed as a major development (10+ units including residential, industrial, commercial and mixed use sites)
  • Located in Flood Zone 2 or 3
  • Drainage area is classed as critical (known surface water issues)
  • Building a new structure or increasing the built footprint of a site

Whilst the characteristics above may not be relevant to your site / development a drainage strategy may be requested by your local planning office. It is always best to check in advance, and if you need any further guidance please contact one of our team.

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