This guidance outlines the circumstances under which a marine licence may be required from the Marine Management Organisation.

Applies to England and Northern Ireland


A marine licence is required to carry out a dredging activity in English Waters or Northern Ireland offshore waters.

Dredging involves the use of any device to move material (whether or not suspended in water) from one part of the sea or sea bed to another part. It includes the removal of material from the sea bed entirely.

Dredging by type

Common types of dredging include:

  • Navigational dredging - to deepen berths and channels for the purpose of navigation. Navigational dredging will usually require a licence but there is an exemption available for low volume dredging and harbour authorities in certain circumstances. If your activity is not exempt then some dredging activities may be suitable for an accelerated licensing process.
  • Clearance dredging - to remove material which has accumulated around a structure or asset for a purpose other than to facilitate navigation. Clearance dredging will usually require a licence but may be suitable for self-service licensing.
  • Aggregate dredging - to extract sands and gravels for construction purposes.

Capital vs Maintenance

Dredging typically falls into two categories:

  • Capital dredging is dredging to a depth not previously dredged, or to a depth not dredged within the last 10 years. Capital dredging is generally undertaken to create or deepen navigational channels, berths or to remove material deemed unsuitable for the foundation of a construction project
  • Maintenance dredging is undertaken to keep channels, berths and other areas at their designed depths. It involves removing recently accumulated sediments such as mud, sand and gravel

To be classed as maintenance dredging the activity must take place where:

  • the level of the seabed to be achieved by the dredging proposed is not lower than it has been at any time during the past 10 years;


  • there is evidence that dredging has previously been undertaken to that level (or lower) during that period.

Samples and analysis

Sample analysis may be needed to support a dredging licence application and will, in most cases, where the application includes disposal of waste (dredged material) to sea. Find out more about sample analysis.

Disposing of dredged waste to sea

Depending on the dredging method used, permission for the disposal of waste to sea may be required as part of the licence. Where this is the case, and if appropriate, a single licence will be issued to cover both dredging and disposal activities.

It is your responsibility to provide all relevant information on the nature of the planned activity when you submit your marine licence application. Find out more about disposal sites and disposal of waste to sea.

Maintenance dredge protocol

Dredging activities need to be assessed for potential impacts on marine protected areas such as European and Ramsar sites. The Maintenance Dredging Protocol for England (MDP) seeks to improve the assessment process for licence applications by the production of baseline documents.

A baseline document should bring together all relevant, readily available, current and historical data on dredging activities. This helps authorities assess maintenance dredging activities and identify any likely significant effect, taking into account in-combination effects of dredging proposals. It must analyse the potential effects (if any) that dredging activities could have on the features of the European sites.

Water Framework Directive

The Marine Management Organisation (MMO) has produced guidance on the Water Framework Directive (WFD) for dredging activity licence applications.

Regional environmental assessments

The marine aggregate industry has voluntarily produced marine aggregate regional environmental assessments (MAREAs) in the Humber, Anglian, Thames and South Coast regions. This is to allow licence applications and EIAs for specific sites to be considered in a regional context and ensure regional sustainability of aggregate extraction.


  • provide a regional baseline for a number of marine aggregate sites
  • help to evaluate potential cumulative effects of existing and future dredging operations.
Published 30 May 2019