Quick Contact

01634 757 705

Flood Risk Assessement

A Flood Risk Assessment is required by regulators to support a planning application or remove objections if a new development (including extensions) or change-of-use proposal (to a more vulnerable use) is located in an area that is at risk of flooding by rivers, the sea or groundwater (or a combination).

The Environment Agency provides detailed guidance on what they would expect to see in a Flood Risk Assessment for different development scenarios, depending on the size of the development, which Flood Zone the development is located in and the vulnerability. To see if your proposed development or property is in a flood risk area, you can simply visit the ‘Am I at risk of flooding?’ website and put in your post code.

As a minimum, the National Planning Policy Framework (NPPF) states that a Flood Risk Assessment must be submitted:

  • With all applications for development of sites in Flood Zones 2 (medium probability) and 3 (high probability) (i.e. such as areas having between a 1 in 100 and 1 in 1000 (1% - 0.1%) or greater annual probability of flooding from rivers or (0.5% - 0.1%) or greater from the sea).

  • With applications for development of sites measuring 1 hectare or more in area in Flood Zone 1 (land assessed as having a less than 1 in 1000 (<0.1%) annual probability of river or sea flooding; and

  • With applications for development of sites measuring less than 1 hectare in Flood Zone 1 but where there is a known risk or history of flooding from other sources.

How can Lustre Consulting help?

Lustre Consulting work with experienced flood risk assessors, hydrologists and engineers to offer a comprehensive flood risk analysis and mitigation service to our clients, complementing our core Contaminated Land Assessment service. 

In order to meet your needs and ensure compliance, our Flood Risk Assessments are carried out in accordance with the National Planning Policy Framework and accompanying Technical Guidance which has retained the main elements of the now withdrawn Planning Policy Statement 25 - Development and Flood Risk. 

Our flood risk assessment services include: 

  • Level 1 Flood Risk Assessment: Screening Study.

  • Sequential and exception tests.

  • Level 2 Flood Risk Assessment: Scoping Study.

  • Level 3 Flood Risk Assessments or detailed studies.

  • Regulatory liaison (such as the Environment Agency).

  • Hydraulic modelling and breach analysis (using 2D TUFLOW software).

  • Drainage strategies (foul water and surface water).

  • Detailed drainage design.

  • Soakage and permeability testing.

  • Contaminated land assessments (land condition prior to discharge to ground).

  • Sustainable urban drainage systems (SUDS).

  • Hydrological assessments.

  • Hydrogeological risk assessments.

  • Environment Statements (to accompany an Environmental Impact Assessment).

In Scotland, the equivalent regulator responsible for flood advice and guidance is the Scottish Environment Protection Agency (SEPA) where technical guidance is available on preparing a Flood Risk Assessment. The Scottish Planning Policy sets out flood risk requirements in line with The Flood Risk Management (Scotland) Act 2009. In Wales it is Technical Advice Note (Wales) TAN15 - Development and Flood Risk.

Points to consider...

Some important points to consider when commissioning a Flood Risk Assessment:

  • It is recommended to firstly check the location of your proposed development or property on the Environment Agency’s ‘Am I at risk of flooding?’ website to give an indication of the Flood Zone

  • As part of the assessment we usually have to contact the Environment Agency to source any data or information. Whilst we always strive to meet your deadlines, the Environment Agency have a 21 day statutory response time. This should be considered when programming your assessment, as even a simple Level 1 Screening Study could take 5 to 6 weeks if we are waiting upon third party information.

  • Whilst you may not need a Flood Risk Assessment to support a planning application, it may be that you are undertaking development in accordance with the Code for Sustainable Homes or work for a utility company with important assets located in the floodplain (such as substations) which requires prevention management.