Flood investigation

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Our duties as Lead Local Flood Authority (LLFA)

As the Lead Local Flood Authorities (LLFA), we investigate flooding incidents. This is part of our legal duties.

Section 19 (S19) of the Flood and Water Management Act states that:

1. On becoming aware of a flood in its area, a lead local flood authority must, to the extent that it considers it necessary or appropriate investigate:

  • which risk management authorities have relevant flood risk management functions, and
  • whether each of those risk management authorities has exercised, or is proposing to exercise, those functions in response to the flood.

2. Where an authority carries out an investigation under subsection (1) it must:

  • publish the results of its investigation, and
  • notify any relevant risk management authorities.

When we investigate flooding

We investigate all reported flooding. We carry out a detailed investigation and may publish a report when:

  • 4 or more properties suffer internal flooding from a single flood event

Internal flooding refers to the habitable part of the dwelling and does not include garages, outhouses and gardens.

  • a single property floods on repeated occasions (at least of 3 times) within 2 years from its initial reported flood
  • there is flooding of any critical infrastructure.

This includes:

  • water and power services
  • railway lines
  • major roads
  • electricity substations
  • police and fire stations
  • hospitals
  • schools or care homes.

If critical infrastructure is internally flooded or there is a loss of services as a result of a flood, it is likely that an investigation would be carried out.

  • a part of the highway floods, making it unpassable and leading to road closures, on repeated occasions within 3 years.

Section 19 flood investigation reports

The  Section 19 investigation threshold is set out in our Local Flood Risk Management Strategy. Once this threshold is reached, a flood investigation report is written as part of our duty as a Lead Local Flood Authority (LLFA).

Barnet Section 19 Flood Investigation Report - 21 July 2021 (ODT, 17.5 MB)
Barnet Section 19 Flood Investigation Summary - 21 July 2021 (ODT, 83 KB)

Request a flood investigation report

You can make a request for a flood investigation report by sending an email to fwm@barnet.gov.uk. We use these reports as a guide only and a request does not mean we will complete a detailed investigation. We may use our discretion to determine whether it is appropriate to launch an investigation into a flood event.