Ordinary watercourse land drainage consents


Ordinary watercourse land drainage consents

If you want to erect or alter an existing obstruction to the flow in an ordinary watercourse, by law you need to get written permission from us including:

  • any mill dam
  • weir or similar obstruction
  • a culvert

Environment Agency mapping shows designated main rivers - any other watercourses are classed as 'ordinary watercourses'.

Retrospective consent

We must give consent before the construction or work begins - you can't ask for it during or after the work has been completed.

Carrying out works without prior consent or failing to rectify problems may be a criminal offence.

Although some proposed structures may not require consent as they don't affect the flow of the watercourse, you will still need to get permission if the construction works themselves could obstruct the flow (e.g. to make a dry working area or to provide access).

So you need to apply if you want to:

  • do work on, over, under or near an ordinary watercourse (within 9 metres of the landward toe of the bank)
  • make changes to any structure that helps control water

Guidance on the activities you want to carry out with example images and what permission is needed:


We recommend emailing us at [email protected] so we can discuss your application and provide full guidance notes.

When you're ready, you can complete an application form online and then email any supporting documents to us.

There is a charge of £50 for each structure or temporary works notice needed. We'll take payment once you have submitted your application and supporting information.

As well as your online application, you'll need to email:

  • site location plan    
  • drawings or figures of proposed works (site plan, engineering layout, cross sections, long sections, construction details)
  • justification for works (if proposing to culvert or obstruct the watercourse). Refer to culverting policy. Clear span structures and minimal obstruction should be sought.
  • flow calculations (existing and proposed) (if required – culverts, obstructions, realignment of channel, etc)
  • method statement for each consentable obstruction/works, detailing:
    • Measures to manage flood risk (sandbag dam, earth/clay dam/bund, over pumping, watercourse diversion etc.)
    • Measures to manage pollution to ensure no contamination of the watercourse (straw bales, sump, silt curtain, silt net, silt mat, chemical boom, drip trays, etc.)
    • Contingency policy (i.e., works during period of bad weather or other unforeseen scenarios)
  • temporary works plan clearly illustrating any temporary flood risk and pollution management measures. Justification for not using temporary works    
  • ecology information (if required - typically only if within or in close proximity to SSSI or when removing or infilling an existing watercourse - check with Natural England our Planning team)    
  • water Framework Directive Assessment (if required)    
  • evidence that the proposals will result in the sustainable flow path through and beyond the site (if required)

We do not accept any responsibility for the design and construction of the works that are the subject of the consents we grant, and any liability for any loss or damage which may arise out of their design, construction, maintenance, or us.

Not getting consent

You can't ask for it during or after the work has been completed.

Works that take place without consent can result in increased flood risk or environmental damage - so we can take enforcement action and serve a notice for the watercourse to be restored to its previous condition within a specified time.

If this is not done, we can carry out these works and recover our costs. 

You can provide evidence that unconsented works have not increased the flood risk - but as we can't, by law, give you retrospective consent, this won't remove liability for any future flooding found to be a result of those works.

Last updated 30 May 2023