Flows deliver many beneficial ecological outcomes to in-stream ecosystems - providing a vector for migration, cues for reproduction and spawning, maintaining water quality and habitat. In-stream communities exhibit a range of attributes that facilitate their resilience to hydrologic disturbances, including morphological, physiological and life history traits at a species level and community attributes at an assemblage level. While considerable research has been conducted concerning ecological responses to flow in Australia's inland catchments, especially with regards to monitoring and predicting the outcomes of altered flow regimes, disturbances and environmental watering, irrigation flows have been largely unresearched. Effects of irrigation water are not currently considered in existing environmental accounting or monitoring and evaluation frameworks within the Murray Darling Basin (MDB). Consequently, possible ecological risks or benefits of irrigation flows are poorly understood.
This project will investigate in-stream ecological outcomes of water delivered for irrigation to ephemeral watercourses in the northern MDB. This will be accomplished by observing spatial patterns and population dynamics of small-bodied fish and macroinvertebrate communities in rivers within the Northern MDB that receive varying levels of irrigation flows. The direct influence that irrigation flows have on instream populations will be investigated, as well as how irrigation flows indirectly impact populations, through altering habitat factors.
This study has the potential to significantly influence water policy and management frameworks in Australia, especially in the MDB. The findings will inform improved management of irrigation flow releases in ephemeral streams to promote ecological benefits and reduce risks. The results will particularly contribute to better integration of irrigation and environmental water management as well as more robust and comprehensive approaches to environmental monitoring and evaluation in this region.