Modelling catchment management impact on in-stream phosphorus loads in northern Victoria

Vigiak, O. and Rattray, D. and McInnes, J. and Newham, L. T. H. and Roberts, A. M. (2012) Modelling catchment management impact on in-stream phosphorus loads in northern Victoria. Journal of Environmental Management, 110. pp. 215-225. ISSN 0301-4797

Abstract

Phosphorus pollution severely impairs the water quality of rivers in Australia and worldwide. Conceptual models have proved useful to assess management impact on phosphorus loads, particularly in data-sparse environments. This paper develops and evaluates the coupling of a point-scale model (HowLeaky2008) to a catchment scale model (CatchMODS) to enhance modelling of farm management impacts on in-stream phosphorus loads. The model was tested in two adjacent catchments in northern Victoria (Avon-Richardson and Avoca), Australia. After calibration of the in-stream attenuation parameter against measurements at gauging stations, the model simulated specific annual phosphorus loads across the catchments well (Nash-Sutcliffe model efficiency of 0.52 in the Avon-Richardson and 0.83 for the Avoca catchment). Phosphorus loads at both catchment outlets under current conditions were estimated at 7 t y -1 and were dominated by field exports. Changes to farm management practices, i.e. the use of perennial pastures in grazing systems and zero-tillage in cropping systems were estimated to reduce phosphorus load by 31% in the Avon-Richardson catchment and 19% in the Avoca catchment, relative to current practices (annual pasture and minimum tillage). The model afforded a major improvement in conceptual modelling by explicit simulation of the impacts of soil and climatic conditions on field-scale exports and by placing them in the context of landscape processes.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access in accordance with the copyright policy of the publisher.
Depositing User: epEditor USQ
Faculty / Department / School: Current - USQ Other
Date Deposited: 06 Dec 2012 12:07
Last Modified: 22 Aug 2014 06:06
Uncontrolled Keywords: CatchMODS; Howleaky; in-stream attenuation; phosphorus model; south-east Australia
Fields of Research (FOR2008): 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070102 Agricultural Land Planning
09 Engineering > 0907 Environmental Engineering > 090702 Environmental Engineering Modelling
04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use)
Identification Number or DOI: doi: 10.1016/j.jenvman.2012.06.013
URI: http://eprints.usq.edu.au/id/eprint/22190

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