Summary 2019-2020 Water Year

The water year started with limited carryover in accounts as there had not been allocations the previous year. General security irrigation users had 2,000 megaltires and environmental water users carried over, 43,000 megaltires.  Essential supplies were secured although it was predicted there would be delivery issues of this water given the low volumes in Copeton Dam and the antecedent conditions.

There was no general security water used for irrigation as deliveries were not possible. There was 18,000ML used from environmental accounts to provide small river flows.

High security users used nearly their highest historical volume of 10,508 ML with water delivered in block releases, often with environmental water throughout the season.

Towards the end of the water year, two small allocations were made to General Security and environmental water users, providing a total of  2.17% allocation.  

In February through to April, there were unregulated flows that would have meet the normal water sharing plan conditions for supplementary access.   Partial access was provided to these flows given the extreme no-flow conditions across the northern basis.  Total access of 20,000 ML was provided (although environmental water managers called on 3,448ML of that) an further 17,800ML would have been available under normal water sharing rules if restrictions were not in place.  Analysis by GVIA indicates that around 10,000ML could have been shared without compromising downstream outcomes if all water sharing plan rules and channel constraints were applied.  This water was foregone by our community.

Essentially these flows were across seven discrete events from January 2020 through to April 2020.  The GVIA includes the January flush event that provided for town water supplies for Weemelah and also, separates the localised flooding in early February as a separate event to the flows that occurred from upstream of Pallamallawa at a similar time.  For this reason, we consider there to be seven events for 2019-20 rather than WaterNSW five. These flows were the first since October 2017

As of 30 June 2020 (the end of the water year) there was 12,560ML of general security water allocation carried over for irrigation and 30,000ML for environmental water managers (NSW and CEWO held, and Environmental Contingency Allowance).  

Key summary:

• Valley inflows were near the lowest on record until February - April, when the region received good rainfall as well as flash flooding.  Total inflows for the valley were approximately 120 GL for the year.
• Irrigators and environmental water holders will carry over remaining water, other than high security into the next year. 
• Temporary restrictions were in place in the region from December 2019 through to late February 2020. During this time, localised flooding occurred with overland flow, unregulated access and supplementary access were trigger but mostly restricted.  Partial access was provided with 18,000ML accessed from the various sources, a further 17,800ML would have been available under normal water sharing rules.  Analysis by GVIA indicates that around 10,000ML could have been shared without compromising downstream outcomes if all water sharing plan rules and channel constraints were applied. This water was foregone by our community. 
• Reserves are such that all essential supplies are secured for two-years and the required delivery loss water is available.
• Groundwater usage totalled 25,358 megalitres.  Monitoring using the three-year rolling average as described in the Water Sharing Plan for the Lower Gwydir Groundwater Water Sources (2016) revealed that usage is below the Plan Limit.

A summary of water usage by category is provided as calculated on 30 June 2020.