Assessment of the catchments that need reductions in nitrogen concentrations to achieve water quality objectives
|14th June 2021
The EPA has carried out an analysis to identify the catchments where nitrogen concentrations are too high to support healthy aquatic ecosystems, or at least Good Ecological Status under the Water Framework Directive.
The reductions in nitrogen in waters that are needed in these catchments has been calculated, and critical source area maps have been developed to help target nitrogen control measures in the landscape. Although achieving Good Ecological Status requires that relevant standards are also met for other quality elements, such as macroinvertebrates, dissolved oxygen, phosphorus, fish and other relevant parameters, for the purposes of this document, the focus is on nitrogen.
This document describes the following:
- The catchments of concern that have elevated nitrogen concentrations;
- The annual load (tonnes) of nitrogen that has discharged from major catchments out to sea over the last decade;
- The annual nitrogen load reductions that would have been needed to keep the nitrogen concentration below the Environmental Quality Standard1 over the decade;
- The sources of nitrogen in the catchments of concern; and
- The critical source area maps that have been developed by EPA to help target nitrogen;
- measures in catchments.
Assessment of the types of actions on land that will be needed to achieve the required reductions in nitrogen in waters is being considered by the Department of Agriculture, Food and the Marine and the Department of Housing, Local Government and Heritage, with support from Teagasc, and is outside the scope of this assessment.
|Catchment nitrogen reductions assessment - June 2021.pdf