The chemical composition and flow of the River Frome and its main tributaries.

Weekly measurements of chemical composition were made at sixteen sampling points on the River Frome and its main tributaries from October 1970 until December 1971. At fourteen of these points stream discharge was measured. Water samples from each sampling point were analysed for alkalinity, calcium, magnesium, sodium, potassium, pH, conductivity, reactive phosphate and nitrate. Magnesium varied little in concentration; alkalinity and calcium concentrations decreased in time of flood. The highest concentration of sodium occurred after snow had melted from salted roads; otherwise it showed little variation. The highest values for nitrate nitrogen were at peak flows but otherwise it altered little. Phosphorus and potassium varied most and both showed a reduction between February and May. These results are part of a survey of the chemical composition of the waters of rivers in the south of England. This survey is aimed at providing a picture of the chemical environment of the rivers as a background for ecological work on the biota, and to investigate the factors influencing variations in chemical composition (Westlake et al., 1972). A preliminary paper (Casey, 1969) has described the flow and chemistry at one point (East Stoke) on the lower part of the river. The present paper is an attempt to discover the contribution each main source makes to the flow and chemistry of the whole river. [ABSTRACT FROM AUTHOR]