Despite dry conditions in the Murray-Darling Basin (MDB) during 2017/18, approximately 950 GL of environmental water was delivered to South Australia, and most significantly, to the Lower Lakes, Coorong and Murray Mouth Icon Site.
The Living Murray program funds a long-term ecological monitoring program that informs environmental water planning and delivery. Monitoring of the Lower Lakes, Coorong and Murray Mouth includes native fish, waterbirds, vegetation, invertebrates and frogs.
In July and August 2017, environmental water originating from the Goulburn and Murrumbidgee Rivers was released from the Lower Murray barrages and fishways to facilitate migration of diadromous fish. More than 50 pouched lamprey were captured and tagged in barrage fishways, and their upstream migration tracked.
In October 2017, in response to reports of black bream running ripe in the Coorong estuary, freshwater flows were released from the barrages to create suitable ‘salt wedge’ conditions in the estuary, to facilitate black bream egg and larval drift. More than 100 juvenile black bream were then captured in the Coorong in April 2018, suggesting suitable conditions had been created to facilitate recruitment.
In November 2017, the annual aerial waterbird survey of the Murray-Darling Basin determined significant waterbird breeding colonies in the Lower Lakes and Coorong; with key breeding species including Australian Pelican, ibis, cormorant and spoonbill.
In March and April 2018, water levels in the Lower Lakes and weir pool below Lock 1 were drawn down to expose sediments. Native emergent vegetation was recorded germinating, and migratory waders utilised newly exposed mudflats for feeding.
Careful planning and delivery of environmental water can achieve multiple outcomes even under dry conditions. Long-term monitoring programs are vital for informing water delivery.