Upper and Lower Namoi River

Upper and Lower Namoi River 
Drought Stage

Stage 2 - Emerging drought

Stage 2 recovering - Upper Namoi - de-escalated from Stage 4 critical to Stage 3 severe on 23 March 2020 and then to Stage 2 recovering on 1 May 2020.

Stage 2 - Emerging drought

Stage 2 recovering - Lower Namoi – de-escalated from Stage 4 critical on 23 March 2020, and then from stage 3 severe to recovering in November 2020.

Storage Levels
  • Keepit Dam increased to 27% (112 GL) by November 2020 from almost empty at the start of 2020.
  • Split Rock Dam remains at 5% (18 GL) and held around 6 GL (3%) on 1 July 2019.
  • The Namoi Valley experienced the lowest inflow between 2017 and 2019 (worst drought) since 1918.
Allocations
  • For both Upper and Lower Namoi, zero for general security, 100% for town and domestic and stock and 90% for high security announced on 1 July 2020.
  • Zero for general security in Lower Namoi also in 2019/20 and all carryover water suspended until 25 February 2020 when suspension lifted.
  • The first general security allocation in the Lower Namoi since August 2017 was made in September 2020 of 4.2% with small monthly increases to November 2020 to 7%.
  • Last Lower Namoi general security allocation made in August 2017.
  • Zero for general security in the Upper Namoi for most of 2019/20 until a 50% allocation was made on 22 April 2020. Suspension of carryover water was lifted on 25 February 2020.
  • Upper Namoi started the 2020/21 water year on zero general security allocations, but a 50% allocation was provided in September 2020.
  • Reduced high security allocations for both the Upper and Lower Namoi Valleys for most of 2019/20 until full high security allocations announced on 22 April 2020, however water being provided through river flows in the Lower Namoi.
Actions
  • Water transferred from Split Rock to Keepit Dam during 2018 and 2019.
  • No releases made to Lower Namoi water users during 2019 and for most of 2020.
  • First release since December 2018 was made in March 2020 to only supply some domestic and stock users immediately below the dam. Access is only available to run of the river flows (not regulated releases).
  • Normal releases are occurring in the Upper Namoi, but may need to cease by summer if storage levels do not improve.
  • A block release for the Lower Namoi will be made in December 2020 and may be the only release for general security users unless storage conditions improve.
  • Natural inflows caused by rainfall in late March 2019 were restricted to town, domestic and stock and high security access only. Some useful flows reached Walgett in April. Restrictions on access repealed on 6 May 2019.
  • Temporary water restrictions (section 324 order) were placed on water users on 6 December 2019 in the Upper Namoi, restricting access to water to secure town water supplies for Manilla township. These have now been lifted.
  • Restrictions on access to inflows applied during January and February 2020 across the Northern Basin limiting access to critical needs. Flows reached Walgett and entered the Barwon-Darling River from 9 February. These restrictions ended late February, with some limited access to certain areas during this period where flows had exceeded target levels.
  • Releases from Split Rock Dam re-commenced from April 2020, once two years reserve for town water supply was available in the storage.
  • Two solar aerators installed in Keepit Dam in 2019.
  • Pian Creek replenishment flow provided in February/March 2020 and in August 2020.
  • Fish refuge pools mapped and fish rescues were undertaken during December 2019.
  • Critical Water Advisory Panel operating.
Issues
  • Because of low water levels boating access to Keepit Dam was limited in 2019.
  • Low flows downstream of Keepit Dam and high temperatures contributed to fish deaths in January 2019 and further deaths throughout the system in November 2019 because of very low water availability.
  • Fish deaths around Narrabri, Gunnedah, Carroll and Boggabri in late January/early February 2020 as a result of short sharp rise in river flows.
Outlook
  • General security deliveries in Lower Namoi to be carried out in a single block release to reduce transmission delivery losses.
  • The Lower Namoi system continues to recover from severe drought conditions. The aim is to build reserves in headwater storages, with tributary flows meeting current orders where possible.
  • Restrictions will be applied in the Upper Namoi to protect town supplies if Split Rock Dam falls to 15 GL.