Alternative model for the ecohydrology of the Murray River

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RESEARCH AREA
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This week’s featured research article has just been published in Ecohydrology by SARDI researchers and proposes an alternative model which integrates ecohydrology and ecohydraulics for the Murray River.

The researcher’s objective was to review the contemporary ecohydrological paradigm for the Murray River by examining historical streamflow and water velocity data, combined with recent hydrological and hydrodynamic models. They explored two propositions, that under natural conditions: (a) the Murray River did not stop flowing and that early irrigation, before main‐stem upland dams and lowland weirs, at times diverted all flow; and (b) the lower reaches of the river were characterized by hydraulically complex, perennial lotic habitats, even in droughts, and there was a regular seasonal pulse of increased hydraulic complexity in spring associated with increased discharge and water velocity.

The authors suggest that these predictable aspects of the Murray’s unregulated flow regime are key features in the development and maintenance of a lotic ecosystem. They discuss the influence of present ecological models of drought on research and management and suggest that a revised view of past conditions would provide new opportunities to improve the ecological integrity of the Murray River.

They also suggest that consideration of spatio‐temporal ecohydraulics has significant global potential to improve rehabilitation of highly modified rivers and the strategic development of large tropical rivers. For global river management, the study raises the profile of hydrodynamics, especially in highly modified—but not necessarily hydrologically impacted—rivers, where the impact of altered hydrodynamics on river ecology may be equal or greater than changes to hydrology. This perspective provides opportunities to refine flow management using ecologically relevant hydraulic objectives; and aid strategic water resource development that values hydrodynamics as a keystone of aquatic ecosystems.

The paper can be downloaded here (or email jennie.fluin@sa.gov.au for a copy).