Preliminary flood risk assessment

6.1 Overview

Defra developed the criteria for assessing whether the risk of flood is 'significant' as required by regulation 14 of the Flood Risk Regulations 2009.

Defra identified National Flood Risk thresholds using 1 Kilometre grid squares where 'local flood risk is an issue'. The 1 km grid square identifies were:

• more than 200 people or
• more than 1 critical service (2 or more)
• more than 20 non-residential properties

might be flooded to a depth of 0.3metres by a rainfall event, with a chance of 1 in 200 of occurring in any given year. Where 5 or more 1km grid squares are touching within a 3km by 3km (9Km²) grid, these are joined to create a cluster. Where a cluster identifies more than 30,000 people at risk of flooding, it has been designated an Indicative Flood Risk Area.

The Borough of Stockton has 4 1kilometre grid squares spread across the authority's boundary with none of them touching. Stockton Borough Council has no Indicative Flood Risk areas in accordance with the criteria produced by Defra.

The Tees Valley has a total of 19385 people at risk of flooding from surface water run off along with 118 Critical Services and 2063 non-residential properties. Therefore this will not be reported to the EU by the EA under the Flood Risk Regulations 2009.