From 2019–24, the Commonwealth Environmental Water Holder Monitoring, Evaluation and Research (MER) Project monitored ecological response to environmental water delivery in the Lower Murray River (LMR). This project extended the Long-Term Intervention Monitoring Project (2014–19) and the knowledge generated from both projects was used to support adaptive management of Commonwealth environmental water (CEW).
From 2014–23, several indicators were used to evaluate ecological response to CEW (mean ~714 GL/y) in the LMR. Three indicators Hydrology, Stream Metabolism and Water Quality, and Fish were used to evaluate Basin-scale objectives and outcomes, and in some instances, also local (Selected Area) objectives, following basin-wide standard protocols. Six indicators (Hydraulic Regime, Matter Transport and Coorong Habitat, Littoral Vegetation Diversity and Productivity (2019-20 onwards), Microinvertebrate Assemblage, Murray Cod Recruitment (2019-20 onwards) and Flow-cued Spawning Fish Reproduction) aimed to address local evaluation questions, using area-specific methods. Additional monitoring and evaluation were conducted in some years for the migration of lamprey at the Murray barrages in winter–spring.
The monitoring demonstrated ecological response to CEW varied among indicators and across years, in association with hydrological variability. This project collected critical long-term data to inform environmental water delivery and flow management in the LMR. It highlights the importance of environmental water in supporting end-of-system flows and the importance of a coordinated approach to environmental water management across the southern connected MDB.