Dáil Éireann Debate, Thursday - 22 January 2026
399. Deputy John Lahart asked the Minister for Housing, Local Government and Heritage to clarify in relation to the designation of heavily modified water bodies for Ireland’s third cycle river basin management plan, if the proposal appeared is to remove the requirement to achieve GES Good Ecological Status and instead aim for GEP Good Ecological Potential; and if he will make a statement on the matter. [5150/26]
Amharc ar fhreagraThe designation of Heavily Modified Water Bodies (HMWBs) is provided for under the EU Water Framework Directive (WFD).
Heavily Modified Water Bodies (HMWBs) are rivers, lakes, or estuarine and coastal waters that have had their physical characteristics such as flow, form and function (hydromorphology) altered to serve a specified use that is beneficial to society. The specified uses under which the current HMWB designations have taken place are:
• Water storage and regulation (i.e. major impounding structures such as dams and reservoirs);
• Flood protection,
• The urban environment,
• Arterial drainage, and
• Navigation.
The WFD requires that all natural water bodies achieve the environmental objective of Good Ecological Status (GES). Designation as a HMWB is an acknowledgment that the water body cannot achieve the objective of GES as a result of its modification. HMWBs therefore must attain a more realistic objective of Good Ecological Potential (GEP). This is the highest condition that they can achieve whilst still supplying a specified use which is of benefit to society.
When setting an objective of GEP for a HMWB the requirement remains to ensure that those elements, which are not sensitive to hydromorphological impacts but sensitive to other pressures such as nutrient or organic enrichment, are considered. Where a pressure is not related to the hydromorphological impacts, such as nutrient enrichment, the environmental target for that element will remain the same as for natural water bodies even if the water body is designated as heavily modified. Only those elements that are directly affected by the physical modifications supporting the specified use are considered when assigning an alternative target (GEP). It is important to note that GEP will reflect the best environmental target that the water body is capable of achieving while the modifications to support the specified use are still in place.
Defining what GEP looks like for each HMWB is the responsibility of the Environmental Protection Agency.
The designation of HMWBs is an iterative process and will be reviewed and repeated in each subsequent River Basin Management Cycle under the WFD. Each review takes into account current technical knowledge and policies in relation to the specified uses under consideration.
