Flood Risk Assessment (FRA)

Michael D Joyce Associates LLP

 

 

Flood Risk Assessments are prepared in accordance with The National Planning Policy Framework (NPPF), which is the official document that regulates the assessment of flood risks and their appropriate mitigation measures in the planning process.  To accompany the NPPF there is the “Technical Guidance to the National Planning Framework” document of March 2012.  This replaces PPS25: Development and Flood Risk.

The National Planning Policy Framework sets strict tests to protect people and property from flooding which all local planning authorities are expected to follow.  Where these tests are not met, national policy is clear that new development should not be allowed.  The mains steps to be followed are set out below which, in summary, are designed to ensure that if there are better sites in terms of flood risk, or a proposed development cannot be made safe, it should not be permitted. 

In areas at risk of flooding or for sites of 1 hectare or more, developers undertake a site-specific flood risk assessment to accompany applications for planning permission.

The policies are based on the Environment Agency’s maps of flood risk zones.  These cover all of England and Wales and map areas prone to flooding in terms of the following.

Zone 1  - Low Probability (Little or No Risk)  

This zone comprises land assessed as having a less than 1 in 1000 annual probability of river or sea flooding in any year.  There are no development constraints.

Zone 2  - Medium Probability (Low to Medium Risk)

This zone comprises land assessed as having between a 1 in 100 (1%) and 1 in 1000 (0.1%) annual probability of river flooding or between a 1 in 200 and 1 in 1000 annual probability of sea flooding in any year.

Zone 3a - High Probability (High Risk)

This zone comprises land assessed as having a 1 in 100 or greater annual probability of river flooding or a 1 in 200 or greater annual probability of flooding from sea in any year. 

Zone 3b - Functional Floodplain

This zone comprises land where water has to flow or be stored in times of flood.  The annual probability that such land will flood will be 1 in 20 or greater.

Flood Risk Zones 3a and 3b are not separately mapped by the Environment Agency (EA).  The advice of the EA is that it is the responsibility of the applicant to determine whether a site is in Zone 3a or 3b in the course of preparing a flood risk assessment.

    The aim of this assessment has been to ensure that the development is sustainable in respect of the following key aims.

    - the development should not be at a significant risk of flooding, and should not be susceptible to damage due to flooding;

    - the development should not be exposed to flood risk such that the health, safety and welfare of the users of the development, or the population elsewhere, is threatened;

    - normal operation of the development should not be susceptible to disruption as a result of flooding;

    - safe access to and from the development should be possible during flood events;

    - the development should not increase flood risk elsewhere;

    - the development should not prevent safe maintenance of watercourses or maintenance and operation of flood defences by the FDA;

    - the development should not be associated with an onerous or difficult operation and maintenance regime to manage flood risk; the responsibility for any operation and maintenance required should be clearly defined;

    - future users of the development should be made aware of any flood risk issues relating to the development;

    - the development design should be such that future users will not have difficultly obtaining insurance or mortgage finance, or in selling all or part of the development, as a result of flood risk issues;

    - the development should not lead to degradation of the environment.

    - the development should meet all of the above criteria for its entire lifetime, including consideration of the potential effects of climate change.