Schedule 6 Consent for Works Affecting Watercourses in Northern Ireland

If your development will discharge surface water to a river, stream or ditch, or you plan to culvert, bridge, divert or cross a watercourse, you will almost certainly need written consent from the Department for Infrastructure (DfI) Rivers under Schedule 6 of the Drainage (Northern Ireland) Order 1973. O’Sullivan Environmental prepares Schedule 6 applications for developers, architects, farmers and homeowners across Northern Ireland, backed by the drainage calculations and drawings DfI Rivers expects to see.

What is Schedule 6 consent?

Schedule 6 of the Drainage (Northern Ireland) Order 1973 is titled “Protection of Watercourses”. It makes it an offence to carry out certain works to or near a watercourse without the consent of the Department, which in practice means DfI Rivers. Its purpose is to stop new structures and discharges from reducing a watercourse’s capacity, obstructing maintenance or fish passage, or increasing flood risk to others.

Under Schedule 6 you need consent before you:

construct or reconstruct a bridge or culvert in or over any watercourse, or alter its waterway;
erect, place, alter or repair any structure in, over or under a watercourse where the work is likely to affect the flow of water, impede drainage works, obstruct fish passage or hinder maintenance;
erect or alter any structure designed to contain or divert the waters of a designated watercourse.

The Order also prohibits placing solid matter in a watercourse, or allowing any discharge that is likely to make it less effective for drainage, unless this is permitted by another statutory provision. This is why new storm water outfalls need to be agreed with DfI Rivers.

Schedule 6 applies to both designated watercourses (maintained by DfI Rivers at public expense) and undesignated watercourses (the responsibility of riparian landowners). A small field drain or roadside ditch can still be a watercourse for the purposes of the Order.

When do you need Schedule 6 consent?

DfI Rivers’ current application form groups works into five categories. Typical examples include:

Discharging storm water to a watercourse: the most common reason for an application on housing, commercial and agricultural sites. DfI Rivers will normally want to see the proposed discharge rate in litres per second, often limited to a greenfield (pre-development) rate, with attenuation to hold back the rest.
Constructing a bridge or culverting a watercourse: for example, a new site access across a stream.
Diverting a watercourse: realigning a channel to suit a site layout.
Crossing under or over a watercourse: utilities, pipelines and cables.
Other works adjacent to or affecting a watercourse: headwalls, bank protection, outfall structures and similar works.

If in doubt, ask before anything is built. Carrying out works without consent is an offence, and DfI Rivers can remove or alter unauthorised works and recover the cost from the person responsible.

Schedule 6 and your planning application

Schedule 6 consent is separate from planning permission, but closely linked. Where a Drainage Assessment or Flood Risk Assessment proposes discharging to a watercourse, DfI Rivers’ advice to the planning authority often depends on whether that discharge is feasible, and consent may be required by planning condition before works begin.

Planning policy also shapes what DfI Rivers is likely to accept. Policy FLD 4 of Revised PPS 15 only permits culverting or canalisation in exceptional circumstances, such as a short length of culvert needed for site access or where engineering reasons leave no practicable alternative. Policy FLD 2 expects a working strip beside watercourses (normally a minimum of 5 metres and up to 10 metres where needed) so that they can still be maintained.

What a Schedule 6 application needs

The information DfI Rivers asks for depends on the type of works, but typically includes:

a completed Schedule 6 application form and site location map;
detailed drawings showing the discharge point and outfall or headwall details;
the proposed discharge rate in litres per second, supported by runoff and attenuation calculations;
for bridges and culverts, pipe or culvert sizes, lengths, invert levels and materials, and for larger schemes manhole locations and inlet and outlet details;
for crossings, depths relative to the existing bed or culvert levels and details of bank protection.

Where accurate levels are needed, we can use our own drone survey data to capture ground levels and bank profiles.

How we help

We handle the Schedule 6 process from start to finish:

Initial review: we check whether consent is needed, whether the watercourse is designated, and what DfI Rivers is likely to require.
Calculations: we calculate greenfield runoff rates, attenuation volumes and pipe or culvert capacities, and consider Sustainable Drainage Systems (SuDS) where they suit the site.
Drawings and application: we prepare the supporting information and submit the application to the relevant DfI Rivers area office.
Liaison: we deal with DfI Rivers’ queries through to a decision.
Joined-up reporting: where you also need a Drainage Assessment or Flood Risk Assessment, we prepare the Schedule 6 application alongside it so that the discharge rates and drawings match.

Related consents to be aware of

Schedule 6 consent deals with drainage and flow. It does not replace other permissions. Depending on your project you may also need:

planning permission from the local council;
NI Water approval, such as a Pre-Development Enquiry or an Article 161 sewer adoption agreement, if any drainage connects to the public sewer;
a discharge consent from the Northern Ireland Environment Agency (NIEA) under the Water (Northern Ireland) Order 1999 if you are discharging anything other than clean surface water, such as treated effluent;
agreement from riparian landowners downstream, and contact with DAERA Inland Fisheries or DfI Roads where their interests are affected.

Frequently asked questions

Do I need Schedule 6 consent for a single house?

Often, yes. If a new dwelling’s storm water will discharge to a stream or ditch, or you need to culvert a watercourse to form an access, consent is required whatever the size of the project. DfI Rivers’ form asks for less detail from farmers and private single dwellings for simple culverts, but the requirement to apply still applies.

How long does DfI Rivers take to decide?

The Drainage (Northern Ireland) Order 1973 sets a three-month period for DfI Rivers to give or refuse consent after an application is made. In practice timescales vary, so apply early.

Is there a fee for a Schedule 6 application?

DfI Rivers’ current Schedule 6 application form does not set out an application fee. Our own fees depend on the site and the works involved, and we provide a quotation on request.

What discharge rate will DfI Rivers allow?

This depends on the site and the receiving watercourse. DfI Rivers commonly asks for discharge to be limited to the greenfield (pre-development) runoff rate, with on-site attenuation for larger storms. We calculate an appropriate rate for your site and agree it as part of the application.

Talk to us about your watercourse consent

Tell us about your site and the watercourse involved, and we will advise on what is needed.

Call 07734 366999 | Email m.osullivan@osullivanenvironmental.co.uk | Contact us