Drainage and floodwater

Local authorities may maintain and improve the surface water drainage network to prevent flooding and facilitate conservation. The local authority legislation permits the Minister for the Environment to make an order for authorities to form joint drainage committees.

The Office of Public Works manages schemes under the Arterial  Drainage Act. Drainage schemes are prepared by the office of public works, which is responsible for river catchment and flood relief schemes. The office of public works may take steps to carry out works which are necessary to prevent flooding where there is a substantial or imminent risk of this occurring.

Where the drainage scheme has been constructed,  there is a statutory requirement to maintain the works that form part of the scheme, including watercourses, embankments, channels, culvert sluice gates and other structures subject to erosion,  siltation and settlement.

European Communities Arterial Drainage Regulations give effect to the public participation directive to ensure that the public is notified of material drainage schemes.

Planning Permission

Drainage schemes carried out by the private sector may be subjected to EIA procedures under planning legislation. Development consisting of the carrying out of works referred to in the Land Reclamation Act 1949 is exempted development.

So also is work specified in a drainage scheme carried out by or on behalf of or in partnership with the Commissioners of Public Works with such additions, omissions, variations or deviations or other works incidental to it as may be found necessary by the Commissioners or their agent or partner in the course of the work.

Instead, such development is subjected to EIA procedures by the Minister for Finance under the Arterial  Drainage Act 1945-1995, as amended by the European Communities (Environmental Impact Assessment) Regulations 1989-1999,83 the Planning and Development Act 2000 and the European Communities (Natural Habitats) Regulations 1997 for proposed drainage works likely to have significant effects on the environment.

EU Flood Risk Directive

Member states are required under the Flood Risk Alleviation directive 2007 to assess watercourses and coastlines at risk from flooding and to take adequate and coordinated measures to reduce flood risk. States are obliged to reduce, and flood manage risks to human health the environment cultural heritage and economic activity.

States are obliged to carry out a preliminary assessment to identify the river basins and associated coastal areas at risk of flooding, and to develop flood risk management plans for the prevention and protection from flood risk.

States must coordinate their flood risk management practices in shared river basins and must consider the long-term development impact of climate change as well as sustainable land use practices flood risk management.

The European Communities (Assessment and Management of flood risk) regulations provide for the implementation of the directive. Public authorities and other organisations must take measures to promote and achieve implementation of the directive. They set out process for assessment and management flood risk including the drawing up of risk reports flood risk and hazard maps and flood risk management plans. Reported Flood Event Data on FloodInfo.ie

Arterial Drainage Schemes

The Arterial Drainage Acts 1945-95  is the  basis for undertaking arterial drainage works in the State.  The legislation is administered by the OPW.  Whenever the OPW is of the opinion that the execution of drainage works is  necessary in a particular catchment area for the purpose of preventing or substantially reducing periodically flooding of lands or improving by drainage lands in that area or where the works are necessary in a watercourse or part of the watercourse with a purpose of preventing or reducing periodical flooding or by improving the drainage land, the commissioners have powers to prepare drainage scheme.

Drainage works which involve execution of drainage schemes which involve works of a class specified in the environmental impact assessment regulations must contain in the schedule, a statement of likely effects of the work on the environment.  In the case of certain class of works not exceeding a quantity area or limited set, the commissioners are to consult with the minister for finance who is direct in environment impact assessment if they would have a significant effects on the environment notwithstanding that being of that limited size, quantity, area or other limit. The information to be provided in the environmental impact assessment is specified.

Process for Approval

The Commissioners having prepared a drainage scheme are to send it to the Council in whose area, the proposed drainage scheme is situate.  Where in accordance with legislation, the scheme contains an EIS, that statement must be sent to a number of prescribed bodies.  The.  Where an EIS has been prepared, a notice must refer to it and state that it is available for purchase.

The council must exhibit a copy of the drainage scheme during the period specified in the notice published by the OPW.  It must examine and consider the scheme and may make observations to OPW within three months.  Making of observations is a reserved function for the councillors.

The OPW must serve on persons named in the drainage scheme as reputed occupiers, proprietors or owners, land proposed to be compulsorily acquired or substantially interfered with and any easement or right of any private road or bridge proposed to be compulsorily acquired, a notice stating that the scheme has been prepared.  They must be given details of the place and time during which the scheme may be inspected.  .

Once the OPW considers observations, consults with the Minister and makes any alternations as it thinks fit, the e scheme is submitted to the Minister for confirmation.  Where an EIS is to be published, the commissioners are to submit observations received by them in relation to the environmental impact of the work.

The Minister may require further information in relation to the environmental impact of the work.  Where further information contains significant data in respect of effects, he may require the OPW to publish notices in the newspaper that significant further information has been sent and is available.  This must be made available for a certain further period.

Once the Minister makes the confirmation order, the OPW are obliged to carry out the scheme.  They are given powers to construct, execute and complete the works specified in the scheme.  They may enter lands for the purpose of carrying out the work.  They may acquire lands, easements or rights compulsory for such purpose.

They may interfere substantially with any law and proposal of the scheme to be interfered with.  They may restrict, terminate easements, fisheries, navigational rights et cetera.The OPW may acquire the relevant rights compulsorily unless they are of the opinion that it is not necessary to do so.

Maintenance of Drainage Works

All drainage works which existed before the act which are maintainable by the councils continued to be so maintainable.  The Minister may make an order transferring the districts to the OPWs  management and control.

Where the OPW is of the opinion that the county council is not properly maintaining works for which they are responsible and works are immediately necessary, they may serve as notice of this repair on the council.  This must state the relevant measure.  The council must undertake the works on notice to the satisfaction of the OPW.  If the council fails to do the works, the OPW may enter the works and execute the drainage works and complete them.  The cost must then be paid by the council.

The minister may on application of the OPW transfer existing embankments to it.  The OPW may construct the substitute embankment if they are satisfied it as necessary for the proper protection of the land served by the existing embankment.

The OPW is obliged to maintain new drainage works or existing drainage works in proper repair and condition.  They need not put it in a better state of repair and condition on the date of the — on which they were transferred to the OPW. The OPW may enter lands, take materials and do all things necessary for the purpose of maintaining the work.


The minister on the application of the OPW may make an order in respect of a particular weir or weirs.  Where an order is made, the persons who are in control of the weir must comply with  directions by the OPW in respect of management and working parts of the weir.  They must comply with bylaws made by the Commissioners under the act in respect of the weir.

It is an offence for a person other than with the consent of the OPW to erect, enlarge or alter any weir or other construction in a watercourse where it may cause flooding unless the action is on a compliance with an order made or notice served by the minister for agriculture under the fisheries act or such land is in the occupation of the person or is consented to by such person. The OPW may grant consent and impose conditions.  A failure to comply is an offence.

Repair of Watercourses

The OPW may serve a notice an occupier of the land requiring him within three months to restore, open up or generally put into repair watercourses that are specified in the notice where the OPW is of the opinion that the watercourse is unable to efficiently discharge water passing through it or from adjoining land due to neglect or inadequate maintenance, the notice may be served. The requirement is not limited to existing drainage schemes of districts.

Where a person receives such a notice, he may object within one month. The commissioners may withdraw the notice or disallow the objection. They have power to enter the land and carry out the works which the occupier is required to do. They may recover the costs.

Where the notice has been complied with the occupier is required to keep  the watercourse clean and open and maintained in proper repair and efficient condition. Reaches an offence.


No local authority, no railway company, canal company, or other similar body, and no industrial concern shall construct any new bridge or alter, reconstruct, or restore any existing bridge over any watercourse without the consent of the Commissioners or otherwise than in accordance with plans previously approved of by the Commissioners.

Any person shall alter, reconstruct, or restore an existing bridge in contravention of this section or shall begin so to do or shall partially so do, the Commissioners may serve by post on such person a notice requiring him—

  • if such alteration, reconstruction, or restoration has not been completed, to desist forthwith therefrom, or
  • in any case, to remove, within a time specified in that behalf in such notice, all work done on such bridge, or
  • in any case, within a time specified in that behalf in such notice, to restore such bridge to its original condition

Any person who claims that the Commissioners have unreasonably refused their approval of plans submitted by him for the construction of a new bridge or the alteration, reconstruction, or restoration of an existing bridge may, by notice in writing to the Commissioners, require such claim to be referred to the Minister or  an arbitrator appointed by the Reference Committee from the Panel of Drainage Arbitrators whose decision thereon shall be final and conclusive.

Compulsory Drainage Orders

The Minister or any council may make representations to the OPW requesting that a specified watercourse not in any existing drainage works or proposed water works be restored, opened up or put into proper repairing condition or a new watercourse be constructed in a specified position.  The request must state the works that are essential for the improvement of the drainage of the specified land that the works required to carry out the works has been provided and that the execution of such works is impeded or prevented solely because of an unreasonable withholding, where the owner or occupier of consent.

The OPW may serve a notice on the party objecting, informing him of the request.  He may send observations for consideration. Following the original request and after consideration of the observation, the OPW may make a compulsory drainage order.  It is an offence to interfere with a compulsory drainage order or interfere with any works executed pursuant to the order.

The legislation creates an range of offences cantered on interfering with works constructed under the Act obstructing OPW

Consent to Alteration

The commissioners, OPW may give their consent to the modification, relocation or alteration of a watercourse embankment and other works that has been completed pursuant to a drainage scheme provided they are of the  opinion that the alteration would not adversely affect the lands or its drainage.  Where works have been altered or modified without consent, the works OPW may do the requisite works and cover the costs as a contract debt.

If a watercourse or other works had been completed pursuant to a drainage scheme, are modified or relocated without consent, the OPW may takes steps as a necessary to prevent flooding.

Agricultural Drainage Works

The European Communities (Environmental Impact Assessment) (Agriculture) Regulations 2011 apply to  land drainage works on lands used for agriculture above a threshold.

A person shall not carry out or allow any of listed activities  other than in accordance with a screening decision or a consent. A person who wishes to undertake the above activities must submit an application for a screening decision where certain thresholds are exceeded, or it may have a significant impact on the environment or European site a natural heritage area or a monument

When the Minister having considered the information is of the opinion that the activity is not likely to have significant impacts or effects this will inform the applicant and the activity may proceed within such period as specified. Where the Minister considers it is likely to have a significant effect on the environment consent is required.

A person shall submit an application for consent if the activity exceeds the threshold or is likely to have impact as above. The application shall include an environmental impact statement or are not sure impact statement. Notice is given to relevant consultation bodies.

Notice of the application is published and there is possibility for statements and representations to be made. The Minister makes the consent decision having regard to the information in the application environmental guidelines by Minister acts of the European Union policies legal requirements and other matters considered relevant.

Application for review of the decision is by way of judicial review in court.

Environmental Impact Assessment

Under the  European Union (Environmental Impact Assessment) (Flood Risk) Regulations 2012.

The Minister shall, as part of his consideration of a proposed flood risk management scheme,  ensure that before approval is given a scheme likely to have significant effects on the environment by virtue, inter alia of its nature, size or location is made subject to an environmental impact assessment.

An environmental impact assessment shall be carried out by the Minister in respect of an application for approval for a flood risk management scheme which would involve the execution of flood risk management works of a class or classes specified in the Regulations.

OPW Environmental Activities

The OPW carries out a range of environmental assessments for various flood risk management plans and projects.

The main assessments are:

Strategic Environmental Assessments

  • Environmental Impacts Assessments
  • Appropriate Assessments
  • Ecological Assessments
  • Consent Requirements for the Construction and Alteration of Watercourse Infrastructure


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Draft Articles; The articles on this website are in draft form and are subject to further review for typographical errors and, in some cases, updating and correction. It is intended to include references to the sources of materials and acknowledgements in the final version. The content of articles with [EU] in the title and some of the articles in the section on Agriculture are a reproduction of or are based on European or Irish public sector information.

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