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Enhancing river flows versus environmental engineering as contrasting approaches to wetland conservation in the Murray–Darling Basin, Australia

Peiqin Ziang, Matthew Colloff , Jamie Pittock

Abstract

Context. In regulated river basins, wetland conservation has focussed on managed environmental flows to achieve outcomes. Two approaches have emerged: one based on ecological principles, the other on environmental engineering. Aims. To compare these approaches, as applied in the southern Murray–Darling Basin: the Constraints Management Strategy (CMS), based on reducing constraints on within-channel flows to enable flooding of wetlands, and the Victorian Murray Floodplain Restoration Project (VMFRP), based on infrastructure to divert water onto floodplains. Methods. We used data from official reports to derive flood frequency, duration and extent and compare economic costs and water use. Key results. At five wetlands along the River Murray, CMS and VMFRP achieved similar flood frequency and duration. CMS achieved similar or greater flood extent except at two of five sites and required no clearance of floodplain trees. CMS was almost ten times cheaper to implement and with lower water price per hectare. Conclusions. There was no clear economic or environmental advantage to implementing VMFRP projects, given that CMS will be implemented under water reforms in the Murray–Darling Basin Plan. Implications. We consider there is a strong case for the Victorian government to reconsider the need to implement the VMFRP projects.

MF25013  Accepted 29 April 2025

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