Flood and Coastal Risk Management

Under the Flood and Water Management Act 2010, Gwynedd Council became a Lead Local Flood Authority, and was given new statutory duties for flood risk management.



We maintain a register of structures or features which, in our opinion are likely to have a significant effect on flood risk in Gwynedd. This register is available for public inspection.

Investigation of flooding incidents

On becoming aware of a flood, we must, to the extent we consider 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.

We will carry out an investigation if any property has flooded internally, if there has been a multiple near miss or if critical infrastructure is affected, and publish the results of our investigation.

Local Flood Risk Management Strategy

We have to develop, maintain, apply and monitor a strategy for local flood risk management within Gwynedd. Local flood risk means the risk of flooding from surface runoff, ordinary watercourses and ground water.

We have also carried out a Strategic Environmental Assessment and a Habitats Regulations Assessment to assess the potential environmental impact of our strategy.

The documents are available here.

Consenting of works in ordinary watercourses

Gwynedd Council is the consenting and enforcement authority for works in ordinary watercourses. Consenting and enforcement of works is needed to control activities that may have an adverse impact on flood risk and the environment.

An ordinary watercourse is any watercourse that is not defined as a main river, The Environment Agency Wales retains responsibility for the consenting of works in main rivers and Internal Drainage Districts in Gwynedd.

An application form and guidance notes for consent to carry out works are available here. It is strongly recommended that you contact the Flood and Coastal Risk Management Unit on 01766 771000 before applying for consent. A fee of £50 must accompany your application.

We have 2 months to determine your application. This period only starts when your application form and all accompanying documents, including the fee, are received in the Dolgellau Office.


Gwynedd Council has the permissive power to designate a structure or feature that affects local flood risk. Our consent would be required to alter, remove or replace a designated structure or feature. We have no power to make someone maintain a designated structure or feature. A designated structure or feature would be entered on the register of flood risk features.