Gaeilge

Flood Risk Measures – Prevention, Protection, Preparedness

Prevention

Flood risk prevention is aimed at avoiding or removing a flood risk. This can be achieved, for example, by avoiding building in vulnerable areas prone to flooding.

These measures include:

• Sustainable Planning and Development Management

In November 2009, the Guidelines on the Planning System and Flood Risk Management, jointly developed by the Department of Environment, Community and Local Government (DECLG) and the OPW, were published under Section 28 of the Planning Acts. These Guidelines provide a systematic and transparent framework for the consideration of flood risk in the planning and development management processes.

• Sustainable Urban Drainage Systems (SUDS)

Sustainable Urban Drainage Systems can play a role in reducing and managing run-off from new developments to surface water drainage systems, reducing the impact of such developments on flood risk downstream, as well as improving water quality and contributing to local amenities.

• Voluntary Home Relocation

In extreme circumstances, the flood risk to a home may be such that the homeowner may consider that continuing to live in the property is not sustainable and would choose to relocate.

• Adaptation Planning

The Government published a National Climate Change Adaptation Framework in December 2012, which mandated certain Government Departments, other public sector bodies and Local Authorities to prepare sectoral and local climate change adaptation plans. A statutory National Adaptation Framework is to be published early in 2018, which will require the OPW to review and update the 2015 Sectoral Adaptation plan for Flood Risk Management.

• Land Use Management and Natural Flood Risk Management Measures

Flood flows depend on how much rain falls in the catchment and the pattern of rainfall, and also on how much and how rapidly the rain runs off the land into the river. The volume and rate of runoff can be reduced by changing land use practices and by implementing measures to increase the retention of rainfall, by slowing the flow of water down catchments and rivers, by protection and/or rewetting of peatlands and bogs and by planting hedgerows across hillsides.

Protection

Flood risk protection is aimed at reducing the likelihood and/or severity of flood events. These measures, typically requiring physical works, can reduce risk in a range of ways, such as by defending areas at risk against flooding, by reducing or diverting the peak flood flows, or by reducing flood levels.

These measures include:

• Major Flood Defence Schemes

Solid structures built between the source of flood waters (rivers, estuaries or the sea) and an area vulnerable to flooding (people, properties, land and other assets) can prevent flooding up to the Standard of Protection of the structure, hence reducing the flood risk in the area being protected by the structure. Such structures typically include walls (generally in urban areas with limited space) or embankments (generally in rural areas and in urban areas where space is available, such as parks), but can also include other built or natural structures, such as sand dunes.

Flood relief works are designed to protect an area up to a certain 'Standard of Protection' and, depending on the type of protection measure, may reduce the severity of flooding above this Standard.

OPW major flood relief schemes are typically designed and built to a minimum standard that protects areas against a 1 in 100 year fluvial flood (flooding from rivers and streams), and coastal areas against a 1 in 200 year flood event, where it is feasible to do so. Schemes are also designed to be cost beneficial, have regard for environmental factors, take account of climate change, and ensure they do not worsen a flood risk upstream or downstream of the protected area.

• Minor Works Programme

The Minor Flood Mitigation Works and Coastal Protection Scheme (the “Minor Works Scheme”) is operated by the OPW to support the Local Authorities through funding of up to €750,000 to address qualifying local flood problems with local solutions.

• Arterial Drainage Schemes

The implementation of Arterial Drainage Schemes began in the late-1940s and continued into the early-1990s. The OPW’s annual arterial drainage maintenance works programme protects 260,000 hectares (650,000 acres) of agricultural lands and comprises 11,500km (7,150 miles) of river channel and approximately 800km (500 miles) of embankments.

• Drainage Districts

Drainage Districts are areas where drainage schemes to improve land for agricultural purposes were constructed under the Arterial Drainage Acts from 1842 up to 1943. Of the 293 schemes carried out, 170 remain covering 4,600km (2,860 miles) of channel, and these are maintained by the relevant Local Authorities.

• Maintenance of Channels not part of a Scheme

Outside of the Arterial Drainage and Drainage District Schemes, landowners who have watercourses on their lands have a responsibility for their maintenance.

Preparedness

In some instances, it may not be possible to reduce the likelihood or severity of flooding to an area at risk. However, actions and measures can be taken to reduce the consequences of flooding, i.e., reduce the risk to people and of damage to properties and other assets, and make sure that people and communities are resilient to flood events. This means preparing for the risk of flooding, knowing when floods are going to occur and, taking appropriate actions immediately before, during and after a flood.

These measures include:

• Flood Forecasting and Warning

Knowing that a flood event is imminent allows people, communities and Local Authorities to prepare for the flood by, for example, erecting temporary defences or moving people and assets out of harm’s way.

Met Éireann currently issue public service weather warnings to Local Authorities and issues weather warnings to the public. Warnings for very heavy rainfall may indicate a threat of widespread flooding or flooding for a specific area. Local Authorities also issues local warnings.

The OPW provides guidance and advice in relation to tide and storm surge forecasts to the National Emergency Co-ordination Group (NECG), Local Authorities and other relevant stakeholders.

• Emergency Response Planning

Well prepared and executed emergency response plans can significantly reduce the impact of flood events, particularly for human health and welfare. The Major Emergency Management (MEM) Framework designates the local authority as the lead agency for co-ordinating a response to a flooding emergency. The Department of Housing, Planning & Local Government (DHPLG) is designated as the Lead Government Department for co-ordinating a national response to a large-scale flood emergency.

• Promotion of Individual and Community Resilience

Individuals and communities that are aware of any prevalent flood risk are able to prepare for flood events so that if and when such events occur, people are able to take appropriate actions in advance of, during and after a flood to reduce the harm and damages a flood can cause.

While the State, through the OPW, Local Authorities and other public bodies can take certain actions to reduce and manage the risk of flooding, individual homeowners, businesses and farmers also have a responsibility to manage the flood risk to themselves, their property and other assets to reduce damages and the risk to personal health in the event of a flood.

Find out more on what steps can be taken at www.flooding.ie.

• Individual Property Protection

Individual Property Protection (IPP) can be effective in reducing the damage to the contents, furniture and fittings in a house or business, but are not applicable in all situations (for example, they may not be suitable in areas of deep or prolonged flooding, or for some types of property with pervious foundations and flooring). Property owners considering the use of such methods should seek the advice of an appropriately qualified expert on the suitability of the measures for their property, and consider the possible requirements for an environmental assessment.

• Flood-Related Data Collection

Data on flood flows and levels, as collected through the hydrometric networks of the OPW, EPA / Local Authorities, the Marine Institute and other organisations, are essential to understand what extreme river flows and levels and sea levels might occur, and hence to enable the appropriate design of structural and non-structural flood risk management measures.

Similarly, recording details of flood events is extremely useful both to increase our knowledge of flood risk in general and to better understand how the flooding occurs in the affected area so that we can calibrate the computer models used to predict potential future flooding.