Land Drainage Consent


If you wish to undertake works on a watercourse then you may need permission under the Land Drainage Act 1991. Who the permission comes from depends on the classification of the watercourse:

Watercourse classification Permitting agency
Main River Environment Agency
Ordinary Watercourse Cornwall Council


If your works are to an ordinary watercourse but within 7 metres of a main river you need consent from both the Environment Agency and Cornwall Council.

You can find out whether a stream or river is a main river on our Flood Risk Map. If you are still unsure then please contact us at land.drainage@cornwall.gov.uk.

Only certain types of works require consent under the Land Drainage Act 1991. These include constructing or altering

  • a mill
  • a dam
  • a weir
  • a new or altered culverts

They also include works which are likely to affect the water flow or capacity of the channel or a defined watercourse. Both permanent and temporary works may require consent.

An Ordinary Watercourse is defined as a watercourse that is not a Main River, and includes:

  • streams
  • drains
  • ditches
  • passages through which water flows

Regulation of works that affect the channel of flow of a watercourse is required in order to:

  • minimise the risk of flooding
  • ensure that there is no increased flood risk on a particular site
  • avoid any adverse effects on people, property and the environment.

The process, under the Land Drainage Act 1991, consists of:

  • issuing consents for acceptable work and
  • undertaking enforcement action when appropriate to deal with unacceptable activities

We encourage you to contact us in advance of applying for consent. This is so that we can:

  • discuss your requirements
  • provide advice
  • ensure that your application is valid and completed correctly

Please note the following timescales associated with the land drainage consent process:

  • The turnaround time for consents is 2 months from the date of payment and a full application being received, as per the Land Drainage Act 1991.
  • In order to avoid fish spawning times, any works being undertaken within ordinary watercourses must avoid the period 1st October – 31st May (inclusive).
  • Please allow time for us to consult with our Environment Agency colleagues where necessary regarding fisheries and biodiversity matters.

For guidance on when and how to apply for consent and to download application and payment forms please use the links below:

Sufficient supporting information must be included in order for us to determine the suitability of your proposals. You must demonstrate that your proposals will not have an adverse effect on local flood risk or the environment. You must also submit an application fee (if applicable, please contact us to confirm). This is currently £50 per structure or operation.

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