Recent highlights from the Flow-MER Program

Science improves our understanding of how plants and animals respond to water for the environment and informs how environmental flows can best support them in the future.

As part of the CEWO’s Monitoring, Evaluation and Research (Flow-MER) Program, quarterly newsletters provide an update of recent monitoring, evaluation and research activities and preliminary observations and findings in the following Selected Areas:

The information is used by water managers to facilitate real-time adaptive management of Commonwealth environmental water. For more information about the Flow-MER Program, please visit the Flow-MER website.

Map of river system in Eastern Australia, highlighting the selected areas

Selected Area Highlights from Issue 16 Outcomes Newsletters (April 2023 - June 2023)

Junction of Warrego and Darling rivers

Salinity levels reduced and dissolved oxygen increased following the Northern Refresh Flow in late April/early May, showing the positive influence of the watering event.

Monitoring undertaken to gain a better understanding of the ecology of the Western Floodplain found several frog species. These included the broad palmed frog, long thumbed frog, desert tree frog, spotted grass frog and Peron’s tree frog.

More detailed information is available in the Warrego-Darling Issue 16 newsletter.

Gwydir River System

Fish diversity sampling using electrofishing and fyke netting in the Gwydir and Mehi Rivers and Carole Creek found Murray cod across all sites, with golden perch observed in the Gwydir and Mehi.

Dissolved oxygen concentration, pH and conductivity largely remained within acceptable ranges, despite low flows at most sites.

More detailed information is available in the Gwydir Issue 16 newsletter.

Lachlan River System

A new population of endangered olive perchlet were located using fyke net sampling near Booligal, with genetic testing underway to determine if they derive from the known population near Brewster.

Murray cod abundance increased compared to previous two years, though no young-of-year were found to give evidence of spawning. This is likely due to earlier flood events disrupting nesting.

More detailed information is available in the Lachlan Issue 16 newsletter.

Murrumbidgee River System

Modelling and simulations were used to predict the best time and temperature for water delivery in order to influence survival rates and lower extinction risk from Amphibian chytrid fungus for the Southern Bell frogs in Nap Nap wetland.

Fish diversity in the Yanco Creek system was higher than previous surveys with freshwater catfish, Murray-Darling rainbowfish, Murray cod and carp gudgeon caught across the sites.

More detailed information is available in the Murrumbidgee Issue 16 newsletter.

Edward/Kolety−Wakool river systems

Monitoring of oxygen refuges from irrigation escapes suggested fish (especially Murray cod) were using the refuges created by environmental water during poor water quality conditions.

eDNA surveys were undertaken in 6 ephemeral creeks in the system, revealing a total of 42 vertebrate species. Notable detections included dwarf flathead gudgeon, rakali and Australasian grebe.

Autumn 2023 fish surveys revealed a huge increase in the number of carp, goldfish and Australian smelt compared to previous years, indicating a large recruitment event on the back of widespread unregulated flooding.

More detailed information is available in the Edward/Kolety-Wakool Issue 16 newsletter.

Goulburn River

Riverbank vegetation has shown good recruitment and a high level of cover, abundance and diversity, likely benefitting from Spring flooding and following low flows.

Data from water loggers has been compared to previous years and suggests that stream metabolism may benefit from small to medium sized pulses delivering new resources for the area, helping to stimulate food supply via primary production.

More detailed information is available in Goulburn Issue 16 newsletter.

Lower Murray River

Analysis of larval samples collected throughout 2022-23 have found hundreds of fish eggs including 420 perch eggs, largely found in the October and November samples.

First Nations students participated in an Indigenous Ecology in Action workshop, co-hosted with Calperum Station, gaining knowledge in cultural values, western science and traditional knowledge of the region.

More detailed information is available in the Lower Murray Issue 16 newsletter.