The Namoi catchment is located in north-western New South Wales covering an area of about 42,000 square kilometres. It is bordered by the Gwydir and Castlereagh catchments. The major river system is the Namoi River, with tributaries including the Peel and Cockburn rivers and Goonoo Goonoo Creek, with major water storages being Keepit, Split Rock and Chaffey dams.
At the start of the 2020–21 water year, reserves in Keepit and Chaffey dams, although slightly improved, were not enough to provide water allocations to general security licence holders or environmental water accounts. With a moderate outlook of rain, but no water for the environment available, the resource availability scenario for the Namoi and Peel rivers was ‘very dry’. The primary focus for water management was to improve water security for towns and where possible, support native fish.
July to December 2020 saw the Namoi and Peel rivers slowly emerge from drought conditions. General rainfall returned, but the drought-depleted soil profile over the catchment saw modest runoff reach storages. However, natural inflows from the tributaries during this period replenished river pools and refreshed water quality along the length of the lower Namoi River.
Widespread rain between January and June 2021 initiated the start of drought recovery in the Namoi and Peel rivers and tributary inflows serviced ecological water demands.
In April 2021, general security licence holders received a 77% water allocation of their shareholding in the Peel River. This available water determination was made to provide 3850 megalitres of Chaffey Dam Environmental Contingency Allowance and 890 megalitres of Commonwealth Environmental Water Holder (CEWH)-held environmental water.
Significant outcomes for the 2020–21 water year included:
- release of 1565 megalitres of Peel Environmental Contingency Allowance (ECA) and CEWH environmental water holdings to support and refresh the Peel River immediately below Chaffey Dam
- natural tributary flows in the lower Namoi River from January to provide connectivity with the Barwon River and inundate the warrambools, higher floodplains and riparian vegetation along the way
- connection of the Namoi River with the Barwon River to provide opportunities for native fish, particularly golden perch, to move between these 2 river systems and begin recovery of population numbers.
Water for the environment is available for the 2021–22 water year with Keepit and Chaffey dams at full supply level.