UK AWMN History
The quality of water draining the UK uplands has been profoundly affected by atmospheric pollution since the onset of the industrial revolution. Of primary concern has been the widespread acidification of lakes and streams by acid deposition, in the form of sulphur and nitrogen compounds derived primarily from fossil fuel combustion.
Controls on acidic emissions were initiated in the 1980s through the United Nations Economic Commission for Europe (UNECE) Convention on Long Range Transboundary Air Pollution (LRTAP) with the specific aim of reducing the impact of acid deposition on soils, vegetation and surface waters. As a result, over the last three decades there have been dramatic reductions in the emissions of S and N gases to the atmosphere in the UK and in Europe as a whole.
To assess the chemical and biological response of acidified lakes and streams in the UK to the planned reduction in emissions, the UK Acid Waters Monitoring Network (AWMN) was established by the UK Department of Environment (now Defra) in 1988 following the recommendations of the UK Acid Waters Review Group (AWRG, 1987).
The AWMN was set up explicitly to monitor responses to reduction of acidifying emissions of S and N, and compare responses along a gradient of deposition (essentially north to south) using acid-sensitive sites in the low-deposition region in the north-west as controls. The Network was also designed to assess the differences between lakes and streams, especially with respect to differences in their respective hydrological regimes, and the differences between sites with afforested and moorland catchments. Site selection attempted to include sites in all the principal acidified regions across the UK.
The 22 AWMN sites are all located in relatively acid-sensitive regions, in upland areas with catchments underlain by base-poor soils and geology. Although monitoring has been underway at most sites continuously since 1988, sampling at certain sites began later and there have also been a small number of interruptions in the record when sampling was not possible. The Network originally comprised 10 stream and 10 lakes sites. In 1990 two sites in Northern Ireland were added (Blue Lough and Coneyglen Burn), supported by funding from the Department of Environment (Northern Ireland). At the start of 1991 the Nant y Gronwen (site 18) was removed from the Network following a request from the landowner and was replaced by a nearby moorland stream, Afon Gwy. More recently, as a result of water abstraction and damming by a local fish farm at Coire nan Arr (Site 1) a new control site was added to the Network, Loch Coire Fionnaraich (Site 23).
Between 1988-2004 data collection and analyses at 20 of the AWMN sites were funded by the Air Quality Division at Defra (previously Department of the Environment), with two sites in Northern Ireland being funded by the Department of Environment (Northern Ireland) (DoE(NI)). The Scottish Executive (SE) and subsequently Scottish Government (SG) contributed 50% of the funding for AWMN work by The Scottish Government's Marine Scotland Freshwater Laboratory (FRS). In 2001 DoE(NI) withdrew from the Programme and Defra took up funding of the Network in Northern Ireland.
Following a funding hiatus at Defra in mid-2007, chemical sampling and analyses at several sites were halted and, more widely, fish surveys and lake macrophyte surveys were cancelled for that year. The reduction in funding was formalised later in 2007 with the annual budget from Defra reduced in 2007-2010 by 78% over 2006-2007 levels.
The reduced Network of sites and analyses that remained after reductions in central funding has been sustained only as a result of significant contributions in kind from CEH and ENSIS-ECRC at UCL; financial assistance from the Welsh Assembly Government, Countryside Council for Wales (CCW), the Environment Agency (EA) and the Forestry Commission (FC); and assistance from Marine Scotland, the School of Biological Sciences, Queen Mary University of London (QMUL) and several private individuals.
Page last modified: 15th August, 2010
Page published: 12 March 2010