Managing decline in groundwater levels

In February 2022 the NSW Department of Planning and Environment published reports on how groundwater levels have been changing since monitoring began in the 1970s-80s across 29 inland alluvial groundwater systems. Department hydrogeologists reviewed and analysed data from 1,300 groundwater monitoring sites.

They looked at how deep the groundwater levels fall during the summer irrigation season and the level to which they recover when the bore pumps are turned off during winter.

Groundwater levels have generally fluctuated within acceptable levels of decline and recovery. However in some localities, with concentrated areas of pumping, groundwater levels are not able to fully recover before the following irrigation season starts.

The reports provide background information for meetings held with community and groundwater licence holders in these areas in March 2022.

We held information sessions in Moree, Wee Waa, Gunnedah, Quirindi and Goolongong in March 2022. The presentation material for these meetings can be downloaded from the Water presentations library.

We invited stakeholders to provide feedback following the information sessions via email until 8 April 2022.

Based on what we heard, the department will do the following.

Upper Namoi Zone 12 and Upper Namoi Zone 8 groundwater sources

• We will further consult with the stakeholders in the Upper Namoi Zone 12 groundwater source and the Upper Namoi Zone 8 groundwater source when we receive feedback from their own discussions on potential options to limit further decline in groundwater levels. Should the current good seasonal conditions change and the department observes groundwater levels are continuing to decline, the department will meet with the stakeholders to discuss management options.

Upper Lachlan Alluvial Groundwater Source

• We will further consult with stakeholders in Management Zone 2 of the Upper Lachlan Alluvial Groundwater Source if the department observes further declines in groundwater levels in these areas.

Lower Namoi and Lower Gwydir groundwater sources

• We met with stakeholders in the Lower Gwydir and Lower Namoi groundwater sources in September 2022 to further consult on how to manage and limit groundwater level declines.
• Submissions were received from both Namoi Water and Gwydir Valley Irrigators Association, these were considered by the department, including an option to change the impact assessment threshold that applies to third-party bores in line with the same criteria for other similar alluvial groundwater sources across the state.

An information sheet has been updated for the Lower Namoi Groundwater Source explaining the state-wide temporary trade process and short-term amendments to the impact assessment criteria relevant to the Lower Namoi.