Flood defence and watercourse works without permission

Drainage body permitted development works in Part 13 of Schedule 2 to the General Permitted Development Order 2015 belong to drainage bodies, and to nobody else. If you are a developer, a landowner or a riparian owner, you cannot use them. That misunderstanding is behind a large share of unauthorised watercourse works, because the works themselves look like maintenance and the rights look as though they attach to the watercourse rather than to the body carrying them out.

What you do have is a different and more awkward set of consents: planning permission where the works are development, land drainage consent for an ordinary watercourse, and an environmental permit where a main river is involved. None of them substitutes for the others.

Which bodies the drainage classes apply to

A drainage body, for these purposes, means a body with statutory powers to make or maintain works for the drainage of land. In practice that is internal drainage boards and the Environment Agency, with separate classes in Part 13 dealing with water and sewerage undertakers.

The rights are tied to the body's statutory function. They permit development by that body, in connection with the improvement, maintenance or repair of a watercourse or land drainage works, together with the disposal of spoil arising from those operations. The function is what carries the right, so an internal drainage board carrying out channel maintenance is within the class and a contractor doing identical work for a private landowner is not.

Local authorities and highway authorities have their own separate rights elsewhere in the Schedule for their own functions. Read the class rather than assuming the one you remember covers the body you are dealing with, because Part 13 has been amended and the classes within it are drafted narrowly.

Operations covered and those excluded

The classes cover operational development connected to the drainage function. They do not cover everything a drainage body might want to do.

Typical covered operations are channel clearance and regrading, repair and replacement of bank protection, repair of existing structures, pumping station maintenance, and the deposit of dredged material on adjacent land as part of the operation.

What falls outside: works unconnected with the drainage function, buildings beyond the limits the class sets, and anything on land where the right is withdrawn. The Order's general restrictions still apply, so an article 4 direction, a condition on an earlier permission removing the right, or the presence of a scheduled monument can all take the works outside permitted development.

Spoil disposal deserves its own thought. Depositing dredged material is permitted as part of the operation, but the material is waste once it leaves the operation, and the waste regime applies independently of planning. Where the sediment is contaminated, the disposal question is a permitting question rather than a planning one.

Why a private landowner cannot rely on them

Riparian ownership brings rights and duties. You may keep the channel clear of obstruction, you must accept flow from upstream and pass it on without obstruction, and you are responsible for maintaining the bed and banks. None of that is a permitted development right.

The distinction that matters is whether your works amount to development at all. Clearing fallen branches, cutting bankside vegetation and removing a localised silt deposit by hand are generally not engineering operations in any meaningful sense, and nobody is going to call that development.

Regrading a channel, culverting a length of ditch, raising a bank into a flood bund, installing a weir, piping a watercourse under a new access or realigning a channel around a development platform all are engineering operations. They need planning permission unless some other right applies. And they need separate consent under the drainage legislation regardless of the planning position.

The notification and prior approval procedures that exist elsewhere in the Order, such as those described in agricultural building prior notification under Part 6, have no equivalent here for private works. There is no light-touch route.

Land drainage consent for ordinary watercourses

For an ordinary watercourse, which means any watercourse that is not a designated main river, consent is required under the Land Drainage Act 1991 for works in, over or under the watercourse that would obstruct or alter the flow. Culverts, weirs, dams, piped crossings and new outfall structures all fall within it.

Consent comes from the lead local flood authority, or from the internal drainage board where the watercourse lies within that board's district. It is a separate application with its own fee, its own timescale and its own technical requirements, typically hydraulic calculations showing no increase in flood risk upstream or downstream, maintenance access arrangements, and a commitment on who maintains the structure afterwards.

Two points are consistently underestimated. Culverting is resisted as a matter of policy almost everywhere, so an application to pipe a ditch to gain developable area should expect refusal unless no alternative exists. And consent can be refused even where planning permission has been granted, which is why the consent should be applied for before the layout is fixed rather than after it. Where the works involve a new or altered access across the watercourse, the highway side runs in parallel, as with dropped kerbs and access under Part 2 Class B.

Flood risk activity permits for main rivers

Where the watercourse is a designated main river, the Environment Agency regulates the works through a flood risk activity permit under the Environmental Permitting Regulations 2016. The permit regime also captures works within a set distance of the bank top of a main river, within a set distance of a flood defence, and works in a flood plain, with the distances differing between fluvial and tidal reaches.

The Agency publishes exclusions and exemptions, and some low-risk activities need only a registration rather than a bespoke permit. Check the current lists, because they are revised and the difference between an exemption and a bespoke permit is several months of programme.

Two further consents commonly sit alongside. Works affecting fish passage or involving in-channel structures may need fisheries consent, and works below the mean high water springs line need a marine licence. Where the works could affect the status of a water body, an assessment against the water environment regulations is also required and the Agency will ask for it.

Ecology obligations that still apply

Permitted development status, where it exists, is a planning answer only. The wildlife legislation is unaffected by it.

Watercourse works routinely engage water vole, which is fully protected and occupies exactly the bankside habitat you are proposing to disturb. Otter resting places are protected too. Add white-clawed crayfish, breeding birds in bankside vegetation, and bats where mature bankside trees are affected. A survey programme and, where needed, a licence or a method statement agreed with the regulator will govern the timing.

Those timings conflict with each other. Fish spawning seasons, the bird nesting season and the water vole active season between them leave a narrow window for in-channel work, usually in late summer and early autumn, and the window moves depending on which species are present. Establish the ecological constraints before you fix the construction programme.

Sequencing consents around a works programme

The order that works, for a scheme involving watercourse alteration:

1. Ecology surveys in the right seasons, and the desk study, before the design is fixed.
2. A pre-application discussion with the lead local flood authority or the Environment Agency about the principle of the works, particularly any culverting.
3. Hydraulic modelling sufficient to demonstrate no worsening of flood risk, with the blockage and residual risk cases.
4. The land drainage consent or permit application, running in parallel with the planning application rather than after it.
5. Planning permission, with the watercourse works described in the application and shown on the approved plans.
6. Discharge of pre-start conditions, including any construction method statement and ecological mitigation.
7. In-channel works within the ecological window, with the agreed method statement and supervision.

Describe all of this in a Planning Statement that makes clear which consents are being sought from whom, because an officer who can see the consenting map is far less likely to impose a condition that duplicates another regulator's control. Hard surfacing associated with access works brings its own drainage requirement, in the same way as the drainage condition attached to Class F hard surfaces does on a smaller scale.

Enter your postcode on PlanScope to see which flood and drainage documents your scheme is likely to need.

This is general guidance, not legal advice; check the position with your local planning authority, the lead local flood authority, the Environment Agency or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.