Cost-effective strategies to mitigate multiple pollutants in an agricultural catchment in North Central Victoria, Australia

Authors

  • Graeme J. Doole,

  • Olga Vigiak,

  • David J. Pannell,

  • Anna M. Roberts

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    • Graeme J. Doole (email: gdoole@waikato.ac.nz) and David J. Pannell are with Centre for Environmental Economics and Policy, School of Agricultural and Resource Economics, Faculty of Natural and Agricultural Sciences, University of Western Australia, Crawley, Western Australia, Australia. Graeme J. Doole is at Department of Economics, Waikato Management School, University of Waikato, Hamilton, New Zealand. Olga Vigiak and Anna M. Roberts are with the Department of Primary Industries, Rutherglen, Victoria, Australia.

  • The authors would like to thank the Australian Research Council for funding and the North Central Catchment Management Authority for their aid in general facets of the study.

Abstract

Strategies to reduce phosphorus and sediment yields are identified for two Australian catchments using a nonlinear optimisation model. This provides novel insight into the cost-effective management of dual pollutants of water courses in Australia. A strong degree of complementarity between the two pollutants is highlighted, given the adsorption of phosphorus to sediment that augments the value of gully and streambank management for mitigation. However, the relationship between the two pollutants is asymmetric. A 30 per cent reduction in phosphorus yield achieves a 75 per cent reduction in sediment yield in one catchment, while a 30 per cent reduction in sediment yield achieves only a 12 per cent reduction in phosphorus yield. Sediment abatement costs are low given the efficiency of gully and streambank management. A 30 per cent phosphorus reduction lowers profit by 3–7 per cent, while a 30 per cent sediment reduction lowers profit by around 1 per cent. Land-use optimisation requires spatial heterogeneity in land-use and gully/streambank management responses. Overall, this research demonstrates the need to determine whether one pollutant is more important than another, while recognising the potential that mitigation practices possess for the reduction of multiple emissions during their evaluation.

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