THE LOIS RIVER MONITORING NETWORK - STRATEGY AND IMPLEMENTATION

The large-scale, highly integrated, multidisciplinary nature of the LO IS rivers programme meant that certain measurements were common to man y LOIS research projects (including water discharge, suspended sedimen t concentrations, pH, conductivity) or depended upon routine weekly or flood-related sampling (eg. for nutrients, metals and organics). This paper describes the underlying strategy which led to the design of th e major observational programme in LOIS rivers and provides informatio n on siting of sample points, field sampling methods, instrumentation and associated chemical analyses. There was a need for field measureme nts to reflect the full range of river flows and to identify critical points for measurement of flux from, and within, the large-scale study river basins. Tests of manual sampling runs against the time series o f river flows indicate good representation of both low to moderate flo ws and extreme flood events in the LOIS rivers field data. Field and a nalytical methods for sampling the wide range of chemical determinands (major and minor elements, trace metals, nutrients, inorganic and org anic carbon and micro-organic pollutants) are outlined. The first LOIS chemical harmonisation assessment, designed to investigate the compar ability and accuracy of the chemical and analytical techniques used by the LOIS community is also reported. (C) 1997 Elsevier Science B.V.