You will need permission if you want to do work on a water course.

This should come from the appropriate authority. This depends on whether the watercourse is classed as a main river or an ordinary watercourse. 

Ordinary watercourses  

An ordinary watercourse is any passage through which water flows which is not part of a main river and includes: 

  • streams
  • ditches
  • cuts
  • culverts
  • dykes
  • sluices and sewers (other than public sewers)

Main rivers are typically larger streams and rivers, but some are smaller watercourse of local significance. If the watercourse is part of a main river you will need to apply for permission from the Environment Agency

To identify whether your watercourse is a main river you can check the Environment Agency’s main river map

Ordinary water course consenting

We are responsible for consenting works that affect the flow of an ordinary watercourse.

If you intend to undertake works which may affect the flow or storage of water, even temporarily, you will need to apply to the Flood and Water Management team for consent. 

Read our what requires consent document that details which activities may need consent and which do not.

Download our ordinary watercourse application form and consent guidance form.

How to apply for permission 

To apply you will need to contact us by: 

Early discussion with the team is recommended to help you avoid unnecessary delays.

Lower Severn Internal Drainage Board  

The Lower Severn Internal Drainage Board (LSIDB) are an internal drainage board. Their drainage district boundary includes low lying land along the Severn Estuary west of the M4 motorway within South Gloucestershire.  

Under the Land Drainage Act 1991, and LSIDB byelaws, they have powers that require you to have Land Drainage Consent from them for work in, on, over and near a watercourse or for any discharges to watercourses within their area. 

Further information can be found on the Lower Severn Internal Drainage Board website.  


As the lead local flood authority we have powers under the Land Drainage Act 1991 to:  

  • take action to put right the effects of any breach or failure to get permission 
  • recover the expenses reasonably incurred from the person in default  

We will carry out enforcement action under the following circumstances:   

  • if work has been carried out without permission  
  • if a watercourse has not been maintained properly and could cause a flood risk
  • if permission has been applied for after work has been carried out 

Our enforcement document covers in greater detail our enforcement powers including an outline of the enforcement process.

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