RIVPACS  Database  & WFD Screening
February 2007


Background to research

RIVPACS is a model that predicts the freshwater macroinvertebrate fauna expected to occur at a site in the absence of pollution. The four current RIVPACS models are based on 835 reference sites from streams and rivers through the United Kingdom. With the advent of the Water Framework Directive (WFD) the concept of the ‘reference condition’ has become explicit within the legislative framework of the European Union. Reference condition has been established as a quality standard against which assessments of biological degradation must be compared. It is therefore essential that Member States can demonstrate that the biological datasets used to define reference conditions meet the criteria of the WFD. The RIVPACS reference site dataset is therefore central to the definition of reference conditions for macroinvertebrates in streams and rivers in the United Kingdom.

The UK RIVPACS models were originally based on minimally impacted sites. These sites were sampled over various phases of RIVPACS development over some 20 years. There is therefore a requirement to reappraise the levels of anthropogenic pressure acting at the RIVPACS reference sites at the time of sampling and where necessary to identify particular sites that fail to meet these new standards.

The Environment Agency, the Scottish Environment Protection Agency and the Environment and Heritage Service are engaged in a European WFD intercalibration process that is currently underway within several Geographical Intercalibration Groups (GIGs). These Agencies therefore need to gain full access to the RIVPACS dataset and its associated pressure data to contribute to the process of setting common standards for reference sites at a European level. As the data underpinning the RIVPACS system is central to the setting of reference conditions for UK streams and rivers, the UK agencies also require the RIVPACS dataset to be available to the public so that their site assessments for WFD monitoring are open and transparent.

Objectives of research

Key findings and recommendations

Ownership of the RIVPACS dataset resides with no single organization and several different organizations consider that they own different portions of the dataset. Formal permissions to release the dataset into the public domain have been obtained from all twelve extant organizations that have been identified as having funded various phases of RIVPACS research. In addition, CEH/NERC has also agreed to release the RIVPACS dataset to the public domain. Terms and conditions relating to the end use of the RIVPACS dataset have now been established. The RIVPACS database has been assembled in Microsoft® Access and can now be downloaded from the CEH web site.

Anthropogenic pressure levels at all 835 RIVPACS reference sites have been summarised by WFD system-A stream types, separately for WFD Ecoregion 17 (Northern Ireland) and Ecoregion 18 (Great Britain). Pressure levels have also been summarised by RIVPACS classification groups and compared to appropriate biotic index values. Forty sites (4.8%) out of the current 835 UK RIVPACS reference sites were identified as potentially unsuitable across the four RIVPACS models (Great Britain 33 (5.4%), Northern Ireland 4 (3.6%), Scottish Highlands 3 (2.7%) and Scottish Islands 1 (1.8%) – one site being in both the Great Britain and Scottish Highlands models). Of these, 29 sites were identified as having either excessive organic or nutrient pollution (or both) relative to other sites in their group, 8 had excessive metals concentrations and 3 had unacceptably low flows. No sites were judged to have unacceptably low pH. Steps should be taken to either remove these sites from future models or to statistically correct for their influence. No sites were judged to have unacceptable levels of morphological degradation, thermal pollution, sedimentation or communities adversely affected by non-native species.

The selection of potential new RIVPACS reference sites must now take account of the WFD definition of reference condition. Any potential new RIVPACS reference sites must be selected in consultation with the UK agencies and be based on a thorough appraisal of environmental stresses to ensure that none of these lie outside the appropriate range for that stream type.

Keywords: RIVPACS database, database documentation, Water Framework Directive
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N.B. The report is available for download from the SNIFFER Website