Ireland has achieved Good Environmental Status when human activities do not result in significant alterations to the waterbody in terms of the spatial extent and distribution of hydrographical conditions (e.g. changes in wave action, currents, salinity, temperature) so that the structure and function of ecosystems are safeguarded. For coastal waters this significant alteration is determined through a Hydromorphological Quality Index developed under Directive 2000/60/EC. Good Environmental Status is achieved when 75% of the area of an MRU achieves a HQI score of 0.75 or higher.

Ireland has achieved Good Environmental Status when human activities do not result in significant alterations to the waterbody in terms of the spatial extent and distribution of hydrographical conditions (e.g. changes in wave action, currents, salinity, temperature) so that the structure and function of ecosystems are safeguarded.

Ireland has achieved Good Environmental Status for offshore areas when the spatial extent of each benthic habitat type adversely affected (physical and hydrographical characteristics and associated biological communities) due to permanent alteration of hydrographical conditions is not significant. Alterations to hydrographical conditions will be considered if a significant physical disturbance or loss is determined as defined in criterion D6C3 and D6C4 respectively.