Daly: Outlook 2016–17
Average rainfall during the typically wetter months of the year is expected across the Daly region, which may contribute to an increase in aquifer recharge. Water use is expected to decrease during the year, which takes into account anticipated climate conditions.
Future prospects
This section looks forward over the next reporting period and considers what water inflows and commitments might affect the region's water resources during the 2016–17 year. Figure S12 shows that inflows into the region's storages are expected to exceed future water commitments, which is likely to result in an increase in water assets at the end of the year.
Figure S12 Water outlook for the Daly region for 2016–17
Expected inflows
At the time of publication, rainfall over the Daly region during the first 6 months of the 2016–17 year (July–December) was above average (Figure S13).
Figure S13 Rainfall deciles for the Daly region from July–December 2016
The next few months, particularly January–March, is usually when the most rainfall occurs in the region and when the majority of the total annual flow in the rivers typically occurs. According to the Bureau of Meteorology's climate outlook (from January 2017), Australia's climate will be influenced by neutral conditions in the Pacific Ocean, which is likely to contribute to average rainfall across the region during the wet season. Therefore, given the current relatively wet soil moisture conditions in December 2016 (see the Bureau's Australian Landscape Water Balance product) attributed to the early wet season rainfall, streamflows and aquifer recharge are expected to be higher than they were during the 2015–16 year.
The expected inflows for the 2016–17 year are based on the 2011–12 year; a period when similar above average rainfall and soil moisture conditions were experienced. The combined expected aquifer recharge from surface water and the landscape (approximately 1,550,000 ML) should exceed the expected discharge from the aquifers (approximately 1,000,000 ML) during the year.
Future commitments
The expected diversions and extractions are based on water use data for the 2015–16 year; however, it is expected that the above average rainfall may decrease the dependence on surface water and groundwater resources for urban water supply and agricultural purposes.
Contingent water assets and contingent water liabilities
Contingent water assets
The Department of Environment and Natural Resources sets extraction limits on groundwater aquifers to protect groundwater-dependent ecosystems. The volume of water that is beyond this extraction limit is considered a contingent water asset for aquifers in the region; however, there is currently not enough information available regarding groundwater resources in the Daly region to allow for a volumetric estimate.
Contingent water liabilities
An important provision of the Water Allocation Plan: Tindall Limestone Aquifer (Katherine) relates to the provision of water for future economic development. The plan provides that if native title is recognised on an application within 5 years of the commencement of the plan the relevant parts of the plan would be amended to include 680 ML for Indigenous commercial development. The rationale for this is that a successful native title application may result in the acquisition of land by Indigenous people. If the application is successful Indigenous-owned land overlying the Tindall aquifer would increase by approximately 2%. In relative water terms this equates to 680 ML.