EU Water Framework Directive : groundwater-dependent rivers and lakes in Northern Ireland

Abstract

The EU Water Framework Directive (WFD) requires that those rivers and lakes that are dependent on groundwater be identified and the pressures on these analysed such that the risk of not meeting their environmental objectives by 2015, as set out in Article 4, can be assessed. This report describes the methodology for identifying and carrying out risk assessments for groundwater-dependent rivers and lakes in Northern Ireland, as part of the initial characterisation process. The methodology reflects UK Technical Advisory Group (UKTAG) guidance. The report details those river water bodies and lakes that are groundwater dependent and assesses which of these are at risk of being significantly damaged as a result of groundwater abstractions and potentially polluting point sources; diffuse pollution is addressed elsewhere. The report does not address quantitative impacts on rivers and lakes from groundwater abstractions outside specified assessment zones; the study addressed localised impacts rather than those due to cumulative groundwater abstractions which affect the overall groundwater body water balance, and the ‘available groundwater resource’. This is reported elsewhere. The risk assessment for lakes has been restricted to those with an area greater than 50 hectares, these being the reporting units agreed for the UK for initial characterisation. Lough Neagh and Upper and Lower Lough Erne, whilst obviously falling within this category due to their significant scale, are reported elsewhere. Of the 673 river water bodies considered, 564 are classified as groundwater dependent. Of the 17 lakes assessed, 10 are classified as groundwater dependent. None of the groundwater-dependent lakes are assessed as being affected by groundwater abstractions. Flows in four river water bodies are possibly at local risk due to groundwater abstractions, and one, the Breckagh Burn, is probably at risk. All groundwater-dependent lakes have been classified as risk category 2b in relation to potentially polluting point sources. Using an approach that assesses the equivalent categories for river water bodies based on the sum of the number of sources within the surrounding assessment zones, regardless of type, 113 river water bodies were classified as risk category 2a and the remainder risk category 2b. The report details data limitations and gaps in knowledge affecting the initial characterisation process used