NaFRA Postcode Flood Likelihood Category (FLC) Database

NaFRA Postcode Flood Likelihood Category (FLC) Database is the latest output using the Risk Assessment for flood and coastal defence for System Planning (RASP) High Level Method Plus (HLM+). It is a broad-brush assessment of the likelihood of flooding at a national scale, based on assessments undertaken for 85 river catchments and coastal cells, where a cell is an area of land measuring 50m by 50m.

The NaFRA Postcode Likelihood Category (FLC) Database is held in Microsoft Access format. Although the database can be queried through a user Form where discrete postcodes can be entered, the entire tables underpinning the user Form can be extracted and used as a single dataset with no user locks in place.

The NaFRA Postcode FLC Database provides flood likelihood information at a postcode unit level, summarising the number of properties in each risk category and also the number of properties that are not at risk within that postcode. It enables a comparison of the relative risks and their distribution within each of these postcode units, rather than a detailed, local assessment of the risk at a specific location. The three risk categories are:

1. low - the chance of flooding each year is 0.5 per cent (1 in 200) or less;
2. moderate - the chance of flooding in any year is 1.3 per cent (1 in 75) or less but greater than 0.5 per cent (1 in 200);
3. significant - the chance of flooding in any year is greater than 1.3 per cent (1 in 75).

The postcodes in the dataset are based on OS MasterMap Address Layer 2 September 2008 and the OS CodePoint November 2008 dataset (Non-Addressable properties).