River Monitoring Results

The main river network in Northern Ireland has been monitored regularly for more than 30 years. Chemical monitoring began in the early 1970s and has been complemented by biological monitoring since 1990. Over 5000 kilometres of Northern Ireland's rivers are now being monitored.

The rivers are monitored both chemically and biologically to assess their water quality and thier level of compliance with a range of national standards, European Union (EU) directives and international agreements.

General Quality Assessment (GQA)

Chemical and biological river water quality is classified each year using the GQA scheme.

Chemical

Chemical quality is assessed my monitoring biochemical oxygen demand (BOD), dissolved oxygen (DO), and ammonia.

There are six quality classes ranging from Very Good to Bad. Monitoring results for rolling three-year sampling periods are used. This means, for example, the GQA chemical classification for 2003 is based on a combination of the results from 2001, 2002 and 2003.

GQA chemical classification system - a detailed explanation of the system

Maps of the most recent available chemical classifications(.PDF 1.21Mb)

Table of the most recent available chemical classifications(.PDF 117Kb)

Biological

Biological classification is based on a comparison of the macroinvertebrate fauna(animals without a backbone visible to the naked eye) found at a sampling site with what would be expected to be found at a site without pollution. The closer the two are the better the biological class of the river. There are six quality classes ranging from Very Good to Bad.

GQA biological classification system - a detailed explanation of the system

Maps of the most recent biological classifications available(.PDF 922Kb)

Table of the most recent available Biological classifications(.PDF 148Kb)

View details of biological monitoring frequency

Freshwater Fish Directive (FFD)

Under the terms of the European Commission (EC) Freshwater Fish Directive (78/659/EEC), 4300km of rivers and canals and 20 standing waters (lakes and reservoirs) greater than 50 hectares in area have been designated as either salmonid (suitable for game fish) or cyprinid (suitable for coarse fish).

Designated waters are required to comply with quality standards set out in the Directive. Compliance is assessed every year using monitoring results for the calendar year.

Maps of the most recent Freshwater Fish Compliance available(.PDF 1.1Mb)

Table of the most recent available Freshwater Fish Compliance(.PDF 193Kb)