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.

Keywords:

• Unsaturated zone
• valdose zone
• rapid through flow
• infiltration

Additional information

Notes on contributors

G Summerell

Greg Summereil leads the Ecosystem Management Science Branch in the New South Wales, Office of Environment and Heritage. His team specialise in developing and implementing research to enable policy and on-ground managers to best plan and deliver multiple outcomes for the cultural, social, economic and environmental interactions. The challenge is that the interactions are not linear in nature or straight forward due to inherent levels of differing complexity. Greg’s teams science disciplines include terrestrial and aquatic biodiversity modelling. Flora and Fauna species conservation and landscape restoration techniques, including impacts of fire. Landscape hydrology, salinity and cultural heritage modelling through to national and regional wind-blown dust and groundcover monitoring and modelling. Greg has 15 years’ experience in natural resource research and management with government research organisations in Australia. He has a doctorate from the University of Melbourne in assessment and modelling of the hydrology, salinity and soils of catchments.

R Grayson

Rodger Grayson was Professorial Research Fellow at the University of Melbourne and Director of the CRC for Catchment Hydrology until his retirement from academia in 2006. He now runs Catchment to Sea Pty. Ltd., a small consulting company, but spends large portions of his time travelling in his boat with his wife. His time is currently split between Australia and the Canadian Arctic.

R Muller

Rob Muller started work with the Department of Land & Water Conservation in 1997 and has produced numerous products to support Landcare, Salt Action and the State Salinity Strategy program in NSW. Most recently he has provided salinity hazard ratings for CMA Catchment Action Plan upgrades. Rob is presently employed as a Senior Scientist in the Science Division of the Office of Environment and Heritage (OEH), providing technical, scientific and analytical support for scientific programs and projects relating to the interaction of hydrology and geology on soils, landforms, biodiversity or other ecosystem components, and undertaking hydrogeological assessment in line with the priorities articulated in the OEH Knowledge Strategies. He is currently developing hydrogeological landscape products in a number of areas across the state to guide targeted landscape management.

G Walker

Glen Walker has been involved in groundwater and salinity research for over 25 years and research management for 7 years. He is a Senior Principal Research Scientist with CSIRO Land and Water in Adelaide and is one of four awardees of the W. E. Wood Award for Excellence in Dryland Salinity Research. He was the Groundwater Team Leader for the Murray-Darling Sustainable Yields Project. Research topics over the years have included groundwater-surface water interactions, recharge and discharge processes, floodplain water and salt balance and modelling groundwater responses to land use change.

V Shoemark

Victor Shoemark has worked in NSW agriculture research (forestry, pastures native and exotic) and environmental management (biodiversity, salinity and hydrology) for over 30 years, running some of the most significant field-based programs in the state.