Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

UK Acid Waters Monitoring Network, 2007-2010 - AQ0804

The UK Acid Waters Monitoring Network (AWMN) has operated since April 1988, generating a large and developing database of chemical, physical and biological parameters at 22 stream and lake sites in the UK. The principal objective of the AWMN is to provide a long term, high quality chemical and biological time series to facilitate the assessment of trends in surface water acidity and associated ecological effects, within the UK. In the next immediate phase from September 2007 to March 2008, budget cuts require that the Network is reduced to 19 sites and that certain methodologies are amended. From April 2008 the AWMN will be reduced still further in number of sites and in the scope of methodologies applied. A detailed work programme for the Network from April 2008 onwards will be submitted for DEFRA's agreement by December 2007. The detailed work programme in this document relates only to the the sites and protocols to be employed until March 2008.

Output will be used to advise DEFRA on trends of recovery from acidification and to populate and test models, such as MAGIC, required to inform emissions abatement policy. The AWMN will provide data and scientific advice to the UNECE International Cooperative Programmes (ICPs) on the Assessment and Monitoring of Acidification of River and Lakes, and Integrated Monitoring, and to the UK Environmental Change Network (within which AWMN lakes are some of the only true representatives of remote upland environments). The AWMN will continue to be crucial in the development of acidification tools under the Water Framework Directive. The Network was designed to cover both lakes and streams across gradients of acid deposition and geological sensitivity. Samples for water chemistry analysis will be taken monthly from streams and quarterly from lakes. Analyses include the measurement of labile alumininium concentration, perhaps the critical parameter with regard to biological effects of acidification. Long and continuing time series of labile aluminium in the UK are unique to the AWMN. Flow will be gauged continuously at five stream sites to allow a better understanding of the changing chemical nature of acid episodes.

Biological sampling of epilithic diatoms, stream macrophytes and macroinvertebrates will be conducted. Palaeoecological diatom analyses of sediment cores carried out at each AWMN lake during the first five years of operation, showed that all but one site had acidified over the industrial period. Material from sediment traps in lakes will be collected annually and used to compare the biological composition of contemporary sediment with that in the historical record. This provides an indication of the current rate of biological recovery from acidification and an estimate of reference condition gap-closure. A detailed study of metal deposition will be undertaken at Lochnagar, the most remote site. Here deposition, lake water, terrestrial and aquatic vegetation will be analysed for heavy metals with particular emphasis on mercury. Sediment from the sediment traps at Lochnagar will also be analysed for a range of heavy metals, and spheroidal carbonaceous particles (SCPs), the latter being an unambiguous indicator of deposition from fossil fuel combustion.

To address the role of changing climate as a confounding factor in the recovery from acidification, thermistors will be used to monitor lake water temperature to provide an understanding of the role of temperature in influencing chemical and biological variability. These already provide unique long time series of upland lake temperatures for the UK. An automatic weather station and automatic camera are located at Lochnagar to provide first-hand information of climatic conditions and ice duration at this "flagship" site.

The longevity of monitoring and consistency of methodologies, combined with state-of-art analytical and interpretative techniques ensures that the AWMN is an internationally unique environmental resource. Consequently the Network and its data contribute to many areas of environmental research in the UK and abroad, well beyond its original remit. Data are currently fundamental to several NERC and EU supported studies of upland water quality.

The AWMN comprises a series of expert laboratories throughout the UK which have been co-ordinated and administered by ENSIS Ltd. at the Environmental Change Research Centre (ECRC), University College London (UCL), since 1989. Results are published in annual reports and made available on the AWMN web page ( Detailed data interpretations are published on a five yearly basis (the next scheduled for July 2010) and have provided the basis for two special issues of scientific journals (Freshwater Biology (1996. Vol. 36); Environmental Pollution (2005. Vol 137).
i) General Objectives

The general objectives are to maintain AWMN operations according to the principles laid down in the original project specification, namely to provide DEFRA with a scientifically rigorous evidence base to inform policy and assist in compliance with EU and international monitoring obligations.
ii) Technical and Scientific Aims

These can be condensed into 7 key activities:

1. Sample for chemical analyses at AWMN sites
2. Measure physical variables at AWMN sites
3. Sample for biological analysis at AWMN sites
4. Analyse chemical variables from AWMN sites
5. Analyse biological variables from AWMN sites
6. Transfer, secure and Quality Assess data and forward to collaborative networks
7. Interpret and report data and provide policy support to DEFRA and the Devolved Administrations on request.
Time-Scale and Cost
From: 2007

To: 2011

Cost: £748,398
Contractor / Funded Organisations
Air Pollution              
Environmental Protection              
Fields of Study
Air Quality