The health of the River Murray valley in South Australia is showing dramatic improvement following a very useful seasonal flood in spring-summer 2016. The flow event peaked at 94,865 ML/d at the South Australian border on 30 November 2016 and had continuous flows >40,000 ML/d for 75 days, meaning that water overflowed onto the floodplain during from mid-October to late December in South Australia. There was a long slow rise in flows, but a very rapid recession.
The wetting of the floodplain kick-started life cycles in plants, animals, birds, fish and frogs. The first signs were deafening frog calls at night and thousands of dragonflies by day. Feeding waterbirds at floodplain pools indicated the presence of macroinvertebrates and small fish to provide their food.
Nardoo waterplants wakened from dormancy in the dry clay and floated in pools like giant four-leafed clover, persisting after the water dried in lush damp pockets. As the flood receded, it left a green carpet of seedlings and a jungle of green growth in lignum bushes. Seedlings and saplings of river red gum and black box which germinated after the 2010-12 floods put on a burst of new growth, adding to the multiple shades of green across the floodplain.
Stressed mature black box trees generated clumps of healthy new leaves and burst into flower. This flood was in the nick of time, to assist recovery of stressed trees, to top up soil moisture and to sustain the growth triggered by the previous floods, continuing recovery from severe vegetation damage in the Millenium drought. The River Murray ecosystem has been given a very welcome boost!