The Living Murray (TLM) Initiative was the first coordinated large-scale river restoration project in the Murray-Darling Basin. The aim was to recover 500 GL of water to be used for environmental outcomes; however, this relatively small volume of water was insufficient to provide significant environmental flows. Therefore, six “Icon Sites” were established with the rationale of delivering water to these sites to achieve and demonstrate a benefit at the site-scale and use this evidence to recover a larger volume of water for basin-scale environmental benefits. The Chowilla Anabranch and Floodplain system was a designated TLM icon site, and to demonstrate site-scale benefits a condition monitoring program for understorey vegetation was established in 2006.
A series of 79 sites across the floodplain were established and resurveyed annually. During the monitoring program, there were two droughts, three large over bank floods (including the third largest on record for the lower Murray in 2022-23), five watering interventions by pumping, construction of the Chowilla Environmental Regulator in 2014 and subsequent operation on seven occasions, and recovery of more environmental water under the Basin Plan.
The change of the floodplain understorey through time and in response to interventions and floods was monitored. The plant community present, typically reflected the previous year’s inundation. There were large changes across the floodplain in response to over bank flooding with extirpation of terrestrial species and recruitment of taxa that rely on inundation. Conversely in areas where there were extended periods without inundation, there was a successional pattern of species with higher water requirements being replaced with more desiccation tolerant species and in the most extreme cases salt tolerant species or bare soil. Pumping and regulator operation resulted in localised recruitment of inundation reliant species with the extent depending on the scale of the intervention.