Flood Risk Assessment

Nimbus Civil and Environmental Engineers > Services > Flood Risk Assessment

Flood Risk Assessment

When submitting a planning application, a Flood Risk Assessment (FRA) may be a compulsory element to gain approval for your proposed development.
By carrying out a FRA, you can learn more about the flooding risks to your site. Flooding can occur from rivers, the sea, groundwater, surface water, sewers and artificial sources such as reservoirs and canals.
This information allows you to make arrangements to minimise any flooding and its associated damage to your property and your neighbouring sites. It also takes into account the risk your development can pose to others, as your site can contribute to the risk of local flooding.

Why do I Need a Flood Risk Assessment?

An FRA may seem like a pricey added hassle to your planning process, but they are extremely important as flooding can cause risk to life as well as badly damage the fabric of your proposed development.
When you design your development, you must consider the impact this can have on flood flow routes, the depth of flooding at the development site and access and egress from the site also.
Any proposed development must not increase flood risk at the site or elsewhere, your development may unintentionally cause floodwater to flow into neighbouring buildings.
An FRA allows you to assess the flood risk your site may pose and give you guidance on how to mitigate this through design and construction, as well as providing information on flood warnings and how the occupants can stay safe during an extreme flooding event.

When are Flood Risk Assessments Compulsory?

There are certain categories to developments that mean Flood Risk Assessments are necessary for gaining planning approval, as required under the National Planning Policy Framework (NPPF) and Environment Agency (EA) guidance. You will need an FRA if your site:
  • Is in flood zone 2 and 3 (this means the area has an annual flood probability of between 0.1% to 1%, and above)
  • Is classed as a major development, 10 units and above for residential or over 1000m2 for commercial developments
  • In flood zone 1 but could be affected by other flooding sources (other than rivers and the sea)
  • Involves a proposed basement in an area with groundwater flooding issues, this will take the form of a Basement Impact Assessment report
  • Is at a medium to high risk of Surface Water Flooding
  • In an area with known critical drainage issues (contact your local authority to find out)
  • Is within 20m of a main river or 16m of a tidal river (Environment Agency)
You can find out more about the flood zone your development is in by checking the UK government’s website here.

When Should You Carry Out a Flood Risk Assessment?

As soon as possible!
We get many enquiries from developers who realise they need a Flood Risk Assessment but have already carried out many stages of the planning process, including drawings and design. This is often a costly slip-up as FRA’s may dictate a vital change in design to achieve planning approval.
That’s why it is so important to get flood risk consultants involved early in the planning of a new development to avoid any heavy add-ons to your budget.
FRAs allow developments to uphold national and local policy guidance whilst also keeping your site secure and sustainable when it comes to flooding.

Choose Nimbus for Your Flood Risk Assessment

Nimbus Engineering are reputable, qualified, and experienced flood-risk environmental consultants.
We provide flood risk assessments to support planning applications for commercial and residential developments in England, providing technical assistance to help your development meet the requirements of the National Planning Policy Framework (NPPF).
We also carry out similar assessments in Scotland, providing advice on Scottish Planning Policy (SPP) and flood consequence assessments to meet the needs of Technical Advice Note 15 (TAN15) in Wales.

Here to help!

Our highly experienced team can also develop flood risk assessments to allow you to meet the necessary standards for obtaining ‘Code for Sustainable Homes’ credits and BREEAM credits. Our rates are extremely competitive for all the assessments which we can carry out on your behalf and we are certain that you will not receive the same service, for the same cost anywhere else.
We would be happy to work with you and your design team to create a bespoke solution to your flood risk requirements, specific to your development and the needs of the wider local area. We will provide you with an FRA that gives you strategies to mitigate flood risk and meet local planning policy.

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