Evidence to support the significance of rapid lateral flow contributions from a subsurface palaeochannel to a stream during event flows

Abstract

Debate over water movement processes and pathway contributions through the landscape into streams remains contested, as often paradox evidence between published studies demonstrate major differences in reported component contributions. The objectives of this paper are to add further evidence to this ongoing debate through using multidisciplinary field-based measurement techniques and a focus around the impact of ancient palaeochannels for directing significant contributions of soil water and solutes into streams in relatively short and reactive time frames during stream flow events. The project involved afield-based study in the Livingstone Creek subcatchment located within the Murrumbidgee valley of inland southern New South Wales, where dryland salinity problems are of major concern. The project investigates the processes influencing salt movement from the landscape to the stream in a upland catchment that also has large areas of river flats and valleys. The major finding of the study was that during rainfall events rapid infiltration of recharge occurred in the unsaturated zones across the alluvial landform.