Annual environmental water priorities in the Gwydir valley

Water managers plan for a range of possible water availability scenarios.

Priorities for 2017–18

Climate models are indicating a neutral El Nino-Southern Oscillation for the second half of 2017 with warmer and drier than average conditions expected in winter across Australia.

Early season rainfall in 2016–17 paved the way for good watering throughout the Gingham and Lower Gwydir watercourses. Due to the dry conditions, water managers, together with the EWAG, are planning limited proactive watering in the year ahead.

Water managers have prepared watering plans that take into consideration a range of weather and water availability scenarios in case it rains more or less than expected. This is known as ‘Resource Availability Scenario’ planning. Dry scenario actions are proposed for the Gwydir valley.

Further details on watering priorities for 2017–18 can be found in the Statement of annual environmental watering priorities 2017–18 (PDF 1MB).

Highlights of 2016–17

Significant natural system flows, positive bird, frog and vegetation response to inundation

The 2016-17 watering season achieved good outcomes for most of the environmental watering assets in the Gwydir valley, especially from good natural inflows into the Gingham and Lower Gwydir watercourse systems, and in the main rivers and connected creeks. Significant natural system flows during September resulted in larger to moderate inundation of the Gingham and Lower Gwydir watercourse systems.

Environmental water manager Daryl Albertson said deliveries of environmental water commenced later in the season, delayed by winter crop harvest constraints.

‘These deliveries, triggered by the earlier season natural inflow events, were made to extend inundation of all areas in eastern and central sections and in most of western portions of remnant wetlands in the Gingham and Lower Gwydir systems over the season.

‘Monitoring revealed a positive bird, frog and vegetation response to inundation. Thirteen species of frogs were recorded. There were 67 waterbird species and a total of more than 140 bird species recorded across the wetlands. Waterbird species included bitterns, brolga, black-necked stork, sandpipers, snipe, ducks, grebes, magpie geese, darters and cormorants. Large numbers (thousands) of several generalist waterbirds species and small numbers (hundreds) of three colonial nesting waterbirds (herons and ibis) were observed breeding, triggered by the larger natural inflows during September 2016.

‘From late December, environmental water deliveries were made into the Gingham, Lower Gwydir and Mallowa systems. There was less extensive inundation along the Mallowa system than expected, with only lower lying core areas in eastern and western areas being significantly inundated.

‘The combination of natural flows and irrigation and environmental water deliveries meant there were sufficient flows during the entire year to support instream values and native fish populations in all reaches of the Gwydir and Mehi Rivers and Carole Creek,’ he said.