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Optimal dynamic water allocation: Irrigation extractions and environmental tradeoffs in the Murray River, Australia
Author(s) -
Grafton R. Quentin,
Chu Hoang Long,
Stewardson Michael,
Kompas Tom
Publication year - 2011
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2010wr009786
Subject(s) - environmental science , irrigation , water resource management , water resources , agriculture , flood myth , irrigated agriculture , hydrology (agriculture) , water balance , base flow , water use , current (fluid) , farm water , drainage basin , water conservation , geography , engineering , ecology , geotechnical engineering , archaeology , biology , cartography , electrical engineering
A key challenge in managing semiarid basins, such as in the Murray‐Darling in Australia, is to balance the trade‐offs between the net benefits of allocating water for irrigated agriculture, and other uses, versus the costs of reduced surface flows for the environment. Typically, water planners do not have the tools to optimally and dynamically allocate water among competing uses. We address this problem by developing a general stochastic, dynamic programming model with four state variables (the drought status, the current weather, weather correlation, and current storage) and two controls (environmental release and irrigation allocation) to optimally allocate water between extractions and in situ uses. The model is calibrated to Australia's Murray River that generates: (1) a robust qualitative result that “pulse” or artificial flood events are an optimal way to deliver environmental flows over and above conveyance of base flows; (2) from 2001 to 2009 a water reallocation that would have given less to irrigated agriculture and more to environmental flows would have generated between half a billion and over 3 billion U.S. dollars in overall economic benefits; and (3) water markets increase optimal environmental releases by reducing the losses associated with reduced water diversions.