Stage 1 - Create legislation
In August 2009 the Department consulted with the public on its proposed legislation for implementing the Floods Directive in Northern Ireland. In November 2009, this legislation was introduced and is known as The Water Environment (Floods Directive) Regulations (Northern Ireland) 2009.
The main requirements contained in the legislation are:
- undertake a preliminary flood risk assessment of all river basins and coastal zones in Northern Ireland by December 2011. On the basis of this assessment, identify all areas at potential significant flood risk
- produce detailed flood hazard maps and flood risk maps for the areas determined to be at potential significant flood risk by December 2013
- produce flood risk management plans that are focused on prevention, protection and preparedness and which contain objectives and measures to reduce significant risk in these areas. Plans must be produced in draft by December 2014 and finalised by December 2015
- co-ordinate efforts with the Republic of Ireland in relation to cross border river basins
- encourage the active involvement of interested parties in the production of flood risk management plans. Co-ordinate flood risk management plans with the involvement of those parties interested in the Water Framework Directive
- make the preliminary flood risk assessment, flood hazard maps, flood risk maps and the flood risk management plans available to the public
Stage 2 - Identify areas at signficant risk
We have completed the preliminary flood risk assessment which is used to identify areas in Northern Ireland where flood risk is most significant. These are referred to as Significant Flood Risk Areas (SFRAs) and will be the focus for future mapping and planning under the Directive.
Preliminary Flood Risk Assessment
To identify SFRAs, the assessment looked at historical flood events as well as the potential for future flooding from all significant sources which for Northern Ireland are rivers, the sea, surface water and impoundments (reservoirs, dams and large ponds). The assessment also took account of climate change predictions.
It examined the consequences that flooding has on the four risk flood classifications defined within the Floods Directive:
- human health
- the environment
- cultural heritage
- economic activity
It is important to note that the focus of the Directive is to identify and manage the risk of flooding where it is considered to be significant at a national level.
Why is a flood risk assessment important?
The assessment ensures that we have the information to identify the areas where flood risk is most significant. This enables us and others to target valuable resources in a coordinated manner to manage risk effectively.
How we undertook the assessment?
We have mapped where previous floods have occurred and using computer models, we can predict the potential extent and impact of future floods. Using a Geographical Information System (GIS) application we determined the adverse impacts on human health and economic activity. We also consulted with the former Northern Ireland Environment Agency on the environment and cultural heritage impacts.
This methodology allowed us to rank areas according to the significance of the flood risk.
What did the assessment show?
Areas with the potential to flood have been mapped which informs us about how many people and properties would be affected and the economic value of potential property damage. Through consultation with others and our own research, further information has been gathered on these areas in relation to demographics, business activity, infrastructure, land use, sites of cultural heritage and environmental importance.
Northern Ireland currently does not have legislation for the management of reservoir safety which means that detailed structural assessments are not available or readily derivable. Without these, it is not possible to accurately determine significant flood risk from reservoirs however DfI Rivers has produced inundation maps which estimate the potential impact of reservoir failure. From these we have identified Reservoir Risk Areas.
DfI Rivers is currently developing a Reservoirs Safety Act for presentation to the Executive in 2014.
Using all of this information have determined the areas that we consider to be at significant flood risk.
Stage 3 - Flood hazard and flood risk maps
Flood hazard and flood risk maps will be produced for each of the Significant Flood Risk Areas (SFRAs) identified in stage 2. The maps will be completed by December 2013 and published on this website as they become available.
These maps will provide a thorough understanding of the impact of flooding and will be an important visual tool to communicate flood risk. They will be used to assist in the selection of objectives and measures in stage 4.
Flood hazard maps
The flood hazard maps will show the areas which may be flooded during each of the following scenarios:
- floods which have a low likelihood of occurrence which is an extreme flood event and is taken to be a 1,000 year event
- floods which have a medium likelihood of occurrence, typically a 100 year event
- floods which have a high likelihood of occurrence or commonly occurring
For each event, the flood hazard maps will show the extent of the flood, the water depth and, where appropriate, the speed of the water flow.
The legislation allows some flexibility in determining which flood scenarios shall be mapped. In the case of coastal areas where adequate protection is in place, the maps may be limited to extreme flood scenarios with a low likelihood of occurrence.
Flood risk maps
The flood risk maps will show the potential consequences associated with each flood scenario. These will focus on the potential effects that the floods could have on the four flood risk classifications.
- human health
- economic activity
- cultural heritage
- the environment
In particular, the maps will show the number of people and the types of economic activity affected, and highlight the location of potentially polluting installations that may adversely impact on environmentally sensitive sites.
Stage 4 - Flood risk management plans
Flood Risk Management Plans are available for each of our three river basin districts, North Eastern, Neagh Bann and North Western. Draft plans were made available for public consultation between December 2014 and June 2015. Taking account of comments we received, following the consultation the Plans have been completed and are published on the website.
The Plans set out a framework in which measures to manage flood risk will be delivered or planned for at a local level. The aim of the Plans is to manage the adverse consequences that flooding could have on human health, the environment, cultural heritage and economic activity.
The Plans focus on the ‘3 Ps’:
in relation to managing aspects of flood risk.
For example they may recommend that:
- structural flood defences are built
- existing flood defence assets are to be maintained in order to ensure that an acceptable standard of flood protection is provided
- we promote natural flood management techniques
- people improve the flood resilience of their homes where no viable structural measure is available
- a flood warning system is developed
Each Plan is tailored to the characteristics of the particular river basin. This means that Plans propose catchment based solutions as well as dealing with local problems individually. The Plans will also be coordinated with the River Basin Management Plans produced under the Water Framework Regulations.
In preparing the Plans, various elements have been taken into account. These may include:
- flood extent and how a flood may develop
- areas which have the potential to retain flood water, in particular natural flood plains
- land use planning
- environmental objectives of the Water Framework Directive
- environmental conservation
- port infrastructure
- cost of suggested measures against the benefits provided
Progress on implementation will be reported and Plans will be reviewed cyclically every 6 years.
As we share three* International River Basin Districts with the Republic of Ireland, we work closely with the Office of Public Works to coordinate our Plans and ensure that our measures do not negatively impact on one another.
* The Shannon International River Basin District can be disregarded from our study as the catchment within Northern Ireland it is very small with no watercourses or flood history and therefore has no areas of significant flood risk.