Guidance

Check if you need a licence to impound water

If you impound water, or plan to, you may need to apply for an impounding licence.

From:
Environment Agency
Published
31 March 2022
Last updated
3 OctoberJuly 20242023 — See all updates

Applies to England

An impoundment is a structure within inland waters that can permanently or temporarily change the water level or flow. This includes:

  • dams
  • weirs
  • fish passes
  • hydropower turbines
  • sluices
  • penstocks
  • culverts
  • lock gates
  • retaining walls
  • flumes
  • reservoir embankments
  • temporary diversions during construction work

You must have an impounding licence before you start work on building a new impoundment structure, even in an emergency. That is, unless one of the exemptions under ‘When you do not need a licence’ applies.

If an existing structure does not currently have an impounding licence, you must get one before you start work to alter or remove the structure.

ThereYou aremay somealso situationsneed whereto apply to the Environment Agency for an environmental permit for a flood risk activity when you maybuild in, over or next to main rivers. For rivers and watercourses that are not main rivers you must apply to your lead local flood authority for consent.

If you want to abstract (take) water, check if you need an impoundinglicence licence.to abstract water.

ExemptionsWhen you do not need a licence

You do not need an impounding licence if your activity is exempt.

Exemptions

TheThere are several exemptions where an impounding licence is not needed.

These are:

  • works constructed without a licence before 1 April 2006, except where a notice is served by the Environment Agency requiring application for a licence
  • where a public authority that manages or owns waterways or harbours constructs any new impoundment, alters an existing impoundment or obstructs or impedes the flow of inland waters while exercising its powers or undertaking its duties
  • where the impoundment is authorised by a drought order or drought permit
  • where structures and works are authorised by legislation (for example an act of Parliament)
  • works constructed or altered by a water company that is authorised by a development control order
  • where the Environment Agency serves notice requiring impoundment only for the purpose of screening or passage for eels

Low risk impoundingimpoundment activities

Some impoundingimpoundment activities have a low impact on the environment and other water users.

CheckThe ifEnvironment Agency will not normally need you canto complyapply withfor an impounding licence for:

The Environment Agency will not normally needrequire a licence application for:

  • refurbishing a sluice
  • re-pointing (block work structures)
  • repairs (for example to applyexpansion forjoint, anstone impoundingpitching licenceor ifbank youor can.

    wall)
  • void filling (‘solid’ structures)
  • managing vegetation
  • de-silting
  • re-positioning (rock, rubble or block work bank protection structures)
  • replacing elements that do not contribute to phased replacement of the whole structure
  • re-facing
  • skimming or covering
  • blockage removal, including screen clearing
  • embankment grouting

Apply

Other foractivities that will not normally require a licence toare:

  • works impoundthat temporarily divert water

Find outduring howconstruction to applyor maintenance of a structure and do not affect any other water users, rights or the environment

  • impounding works or changes to the impoundment to reduce or avoid an immediate threat to human life, property or the environment during an emergency
  • any activity outside the channel, for example on top of the river banks, such as installing or maintaining bridge supports or flood defences
  • work in the river, parallel and adjacent to the bank that does not significantly narrow the channel, for example installing sheet piling, rip rap and rock revetments for erosion protection
  • installing a licencewave wall on an existing reservoir dam that is not intended to impound any extra water.

  • increasing the height of spillway sidewalls (that does not alter the impounding level)
  • altering, moving or constructing a spillway without increasing the impounded level or changing the downstream flow regime to the detriment of the environment

    • Low risk impoundment checklist

    If you impoundanswer water‘no’ withoutto aall licenceof whenthe questions on this checklist, then you are not likely to need onean theimpounding licence. Keep a copy of this checklist for your own records. The Environment Agency may takeask enforcementto action.

    Othersee permissionsyour checklist and supporting evidence which shows how you mayassessed that you did not need

    a licence.

    You

    1. Do surveys reveal any existing abstractions, including unlicensed ones, which may alsobe needaffected toby applythe proposal?
    2. Are there any other water users or riparian rights or interests that may be affected?
    3. Will the changes cause parts of the weir to suffer significantly reduced flows?
    4. Is the Environmentproposal Agencywithin, foror anlikely environmentalto permithave foran impact on a floodSite riskof activitySpecial whenScientific youInterest, buildSpecial in,Area overof Conservation, Special Protected Area or nextRamsar site?
    5. Are planned changes in river flow likely to maincause rivers.significant Forchange riversto andinvertebrate watercourseshabitats?
    6. Does the proposal affect protected species (not fish) that aremay notlive mainat riversthe yousite mustor applyelsewhere in the catchment?
    7. Are planned changes in the river flow likely to yourcause leada localsignificant floodchange authorityin forthe consent.

      Ifmacrophyte youand wantdiatom communities?

    8. Will the proposal impact on either the up or downstream passage of fish (including eels)?
    9. Will the proposal impact on any fish spawning or nursery areas?
    10. Will the proposal cause sediment movement or deposition to abstractbe (take)substantially water,altered checkabove ifor youbelow needthe ansite?
    11. Will licencepollutants be discharged or mobilised into the river during construction or operation?
    12. Is the proposal likely to abstractsignificantly water.

      increase river turbidity or significantly alter movement of sediment?
    13. Does the scheme involve construction of a new raised reservoir with the capacity of 25,000 cubic metres or more?
    14. Will the proposal cause erosion of the river banks up or down stream?

    Get advice

    If you have looked at the section When you do not need a licence and you are still not sure if your proposal needs an impounding licence, you can get advice using the Environment Agency’s enhanced pre-application service.

    Updates

    Apply for a licence to thisimpound pagewater

    Published

    Find 31out Marchhow 2022
    Lastto apply updatedfor 3a Octoberlicence 2024 + showto allimpound updateswater

    Published 31 March 2022
    Last updated 3 July 2023 + show all updates

    1. Explained if you want to alter an existing impoundment structure that does not currently have an impounding licence, you must get one before you start work to alter or remove the structure. Added a link to the flood risk activity permitting page. Clarified the information about exemptions. Clarified that you can request enhanced pre-application advice if you are unsure whether you need an impoundment licence.

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