The use of catchment areas for the study of elemental mobilities is discussed with particular reference to two catchments in north-east Scotland. Underlying geology has considerable influence on their respective stream water compositions, although total annual solute output ultimately depends on the quantity of stream runoff. Tremendous fluctuations in stream water chemistry occur during storms which, it has been suggested, are due to the pathways taken by storm water through chemically contrasting soil horizons. Field sampling of this soil throughflow storm component and laboratory studies involving the leaching of undisturbed soil cores (taken at various depths down the profile) support this conclusion. Relationships between iron, aluminium and organic matter in stream water are discussed in detail. Full use of the available analytical facilities has been made with modifications to existing methods and development of new methods undertaken where necessary.

Automatic river quality monitoring (ARQM) is potentially an important tool in water quality management for the National Rivers Authority (NRA) and similar organisations worldwide. The information produced by ARQM systems must be used in the most effective way and fully integrated with the manual monitoring effort. The status and development of ARQM systems in the freshwater and estuarine River Thames catchment are discussed and a practical appraisal of the design, operation and maintenance requirements given. Data capture, verification and presentation methods are developed and the use of ARQM data for real time management and subsequent analysis is advocated. Examples of data from the freshwater ARQM system are given which emphasise the variability of freshwater quality and the need for a comprehensive understanding of the behaviour of rivers before management decisions are made. The use of ARQM data for assessing the compliance of rivers with River Quality Objectives is examined. With respect to the tidal Thames, data processing methods to correct for the tidal movement of the waterbody are developed. ARQM data are used to highlight the principal factors affecting the water quality of the tidal Thames. The importance of the use of ARQM information in the effective management of the tidal Thames is discussed and operational examples demonstrate how it may be utilised as a basis for management decisions. The application of ARQM to the sub-tropical environment of the River Ganges, India, is investigated. An ARQM system has been designed and prototypes are operational. Extensive site surveys were carried out and the water quality status of the Ganges is discussed. Recommendations for the improvement and future development of ARQM systems are made. The use of ARQM information and its potential for improving the management of rivers is discussed.