Historical stream salinity trends and catchment salt balances in the Murray - Darling Basin, Australia

Abstract

This paper summarizes the results from a study of historical stream salinity trends and catchment salt balances within the Murray–Darling Basin, Australia. A broad analysis of stream salinization was necessary to assist prediction of the increase in the effect and extent of dryland salinity across the basin. The sparseness of the water-quality data necessitated the development of an innovative statistical trend technique that also allowed for the high autocorrelation of the stream salinity data which was often present.Results showed the spatial distribution of stream salinization and identified regions of concern. The salinization characteristics of four distinct geographical regions were identified by providing a spatial analysis of catchment salt balances and stream salinity trends. The salinization behaviour of each region was also related to distinct physical processes. The most significant rising trends and catchment salt output/input ratios were in the zone with 500–800 mm year–1 rainfall in the southern and eastern dryland region.