Identifying the Separate Impact of Farm Dams and Land Use Changes on Catchment Yield

Summary

This paper presents a method for determining the impact of farm dams on streamflows independent of changes in climate and other land-use. The method is comprised of two components: first, the assessment of the statistical significance of trends in streamflows independent of climatic variation, and secondly, the use of a simulation model to determine the proportion of the assessed trend which is attributable to the impact of farm dams. The method has been successfully applied to a number of catchments throughout Australia. Two case studies have been selected to illustrate its practical application, namely the Marne River catchment in South Australia and the Yass River catchment in New South Wales. The results obtained for these catchments indicate that the nature and magnitude of trends estimated by the two largely independent methods is entirely consistent with the documented changes in farm dam development and other land use changes. There would appear to be a direct correlation between the volume of farm dam development and the decrease in streamflow yield, such that for every 1 ML of farm dam development there is a corresponding decrease in streamflows of between 1 ML to 1.3 ML.

Additional information

Notes on contributors

B Neal

Brad Neal is a hydrologist with the catchment management group of Sinclair Knight Merz. He graduated from Monash University in 1996 and holds a B.E. (Hons.) in civil engineering and a B.A. (Hons.) in German studies. As a consultant, Brad’s principal area of study has been the provision of technical support to the Victorian and NSW State Governments on the hydrologic effects of farm dams. He also has interests in REALM modelling, rainfall-runoff modelling, drought planning and statistical trend analysis.

R J Nathan

Dr Rory Nathan is the Principal Hydrologist with the catchment management group of Sinclair Knight Merz. He holds a B.E.(Hons.) from the University of Melbourne, a D.I.C. and M.Sc. in groundwater modelling and engineering hydrology from the University of London, and a Ph.D in low flow hydrology from the University of Melbourne. Rory has over 20 years of experience in both consulting and academic positions, and maintains an active interest in research at both Melbourne and Monash universities. He was recently awarded the national Civil Engineer of the Year by the Institution of Engineers.

S Schreider

Sergei Schreider obtained his M.Sc. degree in mathematics from the Department of Mechanics and Mathematics at the Moscow State University in 1982. In the period from 1983 to 1992 he worked in the Institute of Physics of the Earth, then in the International Institute of Earthquake Prediction Theory and Mathematical Geophysics (Ac. of Sci., Russia). In 1996 he obtained a PhD degree in Resource Management and Environmental Science at the Centre for Resource and Environmental Studies, the Australian National University (ANU). At present he is working as a Research Fellow at the Integrated Catchment Assessment and Management (iCAM) Centre, at the ANU. His major research interests are the modelling of geophysical systems, surface hydrology and climate change impact studies. He is also interested in the problems of integrated catchment management in Australia and the Asia Pacific region. The results of his research have been reported in more than 60 research publications including 25 Journal papers and book chapters. He has held a number of visiting positions in different research Centres in the UK, India and Italy.

A J Jakeman

Tony Jakeman obtained his B.Sc degree in pure and applied mathematics from the University of New South Wales in 1973, and his Ph.D. in applied numerical analysis from The Australian National University in 1976. He is currently Professor of Environmental Systems at the Centre for Resource and Environmental Studies, A.N.U. and Adjunct Professor at the University of Western Australia. He is also Director of the Integrated Catchment Assessment and Management Centre at ANU. He has held visiting positions at Cambridge University, University of Lancaster, Stanford University, CSIRO and the Institute of Hydrology (UK). Tony is Editor-in-Chief of the Elsevier journal, Environmental Modelling and Software, and President of the Modelling and Simulation Society of Australia and New Zealand, Inc., and President of the International Environmental Modelling and Software Society.