State of the Park

Llyn Mymbyr, Snowdonia

alt=View from Snowdon Summit

The United Kingdom Acid Waters Monitoring Network

The United Kingdom Acid Waters Monitoring Network

The United Kingdom Acid Waters Monitoring Network (UKAWMN) was established in 1988 to monitor the ecological impact of acid deposition in those areas that are believed to be sensitive to acidification. Its data-base provides a long-term record of water chemistry and biology which is unique for upland freshwater systems in the UK. Two lakes in Snowdonia (Llyn Llagi near Cnicht and Llyn Cwm Mynach in the Rhinogydd) are monitored under this scheme. Biological and chemical monitoring takes place on a quarterly basis, and epithilic diatoms and benthic invertebrates are sampled annually. The results are published annually by the Network.

The United Kingdom Acid Waters Monitoring Network 10 year Report 1988 – 1998 (March 2000) reported the following (Source: UKAWMN www.ukawmn.ucl.ac.uk):

  • There is strong evidence from Llyn Llagi that there is long term chemical and biological recovery from acidification. The UK Acid Waters Monitoring Network 20 Years Interpretive Report noted that there was continuing significant recovery from acidification at this site.
  • Llyn Cwm Mynach sediment cores indicate that acidification was occurring until relatively recently, exacerbated by forestry within the catchment. Few clear changes in lake chemistry occurred in the10 year period running up to 1998. The more recent The UK Acid Waters Monitoring Network 20 Years Interpretive Report found slight evidence of recovery from acidification

Although pollutant concentrations have decreased in response to emission controls the recovery of Snowdonia’s ecosystems from acidification is taking longer and on-going levels of pollutants (such as nitrate and ozone) are still likely to be having a negative impact on semi-natural habitats. Avoiding such impacts is the key driver behind the UK Air Quality Strategy which set air quality objectives for a number of major pollutants to be achieved by 2020.