Stark inflow figures tell tale of drought severity

Stark inflow figures tell tale of drought severity

10 January 2019

Northern NSW river systems which feed the Barwon-Darling system and then Menindee lakes, can expect an average of approximately 4000 gigalitres (GL) of annual inflows according to long term data.

  • In 2016-17 inflows into the state’s northern river systems was 7800 GL.
  • In 2017-18 those northern rivers received just 542 GL.
  • In the first six months of 2018-19 these rivers received 30 GL.

These record low inflows into northern NSW rivers over the past two years have resulted in many waterways ceasing to flow, with climbing summer evaporation rates placing further pressure on falling supplies. Regional dam storages have extended supply and flow for as long as possible.

This has resulted in the northern dams being reduced to very low levels, with Keepit in the Namoi valley now almost dry, and Copeton in the Gwydir valley at 15% of capacity and facing critical low levels this summer if good rainfall does not occur.

Northern valley dam storages have filled in three years of the past 10 years (2010-11, 2011-12, 2016-17) as did the Menindee Lakes at the bottom end of the system.

During this 10-year period there was 35,000 GL of inflows to the northern rivers, 28,000 GL – or 80% - of these inflows occurred in these three years.

Of the 35,000 GL of inflows over this period less than 20% of the water was extracted.

In 2016-17 the flows from the northern rivers resulted in Menindee Lakes filling, receiving over 1,900 GL of inflows. Over the past two year this 1900 GL has been used accordingly:

  • MDBA requirements - 360GL or 20%
  • NSW Government environmental orders - 210 GL or 11%
  • Maintaining river flow/habitat - 200 GL or 10%
  • Lower Darling customers - 100 GL or 5%

About 1,000 GL or about 55% was lost to evaporation and seepage.

WaterNSW drought information.

Media contact: Tony Webber 0428 613 478.

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48.2
Sunday 20 October
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Sunday 20 October