RIVPACS - USA

Freshwater ecologists at CEH in the UK pioneered the RIVPACS type approach. However it has been trialled, and in some cases adopted, in many countries seeking to establish a national or regional freshwater bioassessment scheme. 

In the USA the multimetric approach has been the most commonly used technique in monitoring water quality. This involves the measurement of an array of metrics or indices that each provide particular information on the state of the site, and, when integrated to a single value, also provide an overall indication of the sites ecological condition. Such an approach has been found to work effectively throughout the USA. However studies have shown that the multimetric approach is not always as precise or accurate as the RIVPACS type approach. The behaviour of multimetric results is strongly influenced by natural physical gradients and this creates difficulties for defining the target value (or reference condition). In response to this problem, individual states within the US have their own specific multimetric approaches, which in turn make nationwide comparisons rather complex. As mentioned previously the combination of multimetrics with a RIVPACS type approach would provide the best of both worlds, because the target multimetric value would be standardised by stream type specific predictions. 

RIVPACS type models have been constructed for watersheds in a number of states in the US (eg California, Colorado, Oregon, Washington). A recent study by biologists at the Western Center for Monitoring and Assessment of Freshwater Ecosystems (external link) at Utah State University (Hawkins et al. 2000) evaluated the use of RIVPACS-type models. They concluded that the RIVPACS approach was based on sound scientific principles and that it was highly effective. They also recommended that the RIVPACS approach should be evaluated elsewhere in the US. The Western Center for Monitoring and Assessment of Freshwater Ecosystems at Utah State University has a Predictive Models section on its web site that describes the background to their models, construction and application of the models and a usefully organised literature section.