Murray-Darling Basin
Future

This note provides information about future water prospects in the Murray–Darling Basin (MDB) region. Information on water assets and water liabilities for the 12-month period after the reporting date that are contingent to future events within the region is included in the Contingent water assets and water liabilities note which follows this Future water prospects note.

The following table summarises information on future prospects in the region between 1 July 2011 to 30 June 2012.

– Data not available

¹ Total water assets in the table includes volume of water held in storages, lakes and wetlands connected to rivers, weirs, locks and river reaches in regulated rivers, inter-region claim on water, and ground water assets.

² Conveyance water includes base volumes held in weirs, locks and river reaches in regulated rivers. These volumes are not available for delivery under normal circumstances, and have to be maintained to deliver water to settle liabilities and commitments.

³ Inactive storages are lakes and wetlands (e.g. Lake Alexandrina and Lake Albert) from which water is not available to settle water liabilities and future commitments within 12 months of the reporting date.

⁴ Water liabilities on 30 June 2011 include remaining surface water and groundwater allocations to entitlement holders.

Reliable information on future water commitments expected to be settled within 12 months after the reporting date is not available. However, taking into consideration the following facts (subject to actual climatic conditions in the 2011–12 year), it is highly likely that future water commitments expected to be settled within 12 months of the reporting date will be settled:

• During the 2010–11 year, the volume of water provided to meet demands associated with statutory water rights and entitlements was 6,372,847 ML. For the 2011–12 year, some of the expected abstractions would actually settle some of the remaining water liabilities, so that actual future commitment would be less than the volume diverted in the 2010–11 year.

• Storage evaporation and other losses, conveyance losses and environmental obligations have to be met from available water resources. It appears available resources are sufficient to meet these requirements. Total surface water evaporation loss reported for the 2010–11 year was 3,505,568 ML (line item 17.1 Evaporation from surface water).

• There will be future water rights to be realised during the 2011–12 year.  They include the required annual release (RAR) that Snowy Hydro is required to deliver to the Tumut River and River Murray, and a claim by Grampians Wimmera–Mallee Water in the Glenelg Catchment.  The volumes for these claims were 3,137,066 ML from Snowy Hydro and 308 ML from the Glenelg Catchment for the 2010–11 year (line item 9.15 Increase of inter-region claim on water). However, the actual volume to be provided by Snowy Hydro is contingent to dry inflow sequence volume reduction for the year (a variable to reflect actual inflow during the year) and volume of water provided by Snowy Hydro to New South Wales irrigators under separate agreements.

• Reliable information on inflows anticipated within 12 months after the reporting date is not available. The net inflow to surface water after river losses was 31,896,551 ML for the 2010–11 year (line items 9.4 Runoff to surface water and 17.10 River and floodplain leakage, evaporation and errors).

This note provides information on water assets and water liabilities for the 12-month period after the reporting date that are contingent to future events in the Murray–Darling Basin (MDB) region. Information on water assets and water liabilities that are certain for the 12-month period after the reporting date is included in the above Future prospects note.

Contingent water assets – non-extractable portion of groundwater

Jurisdictions are responsible within the MDB region for setting annual extraction limits on the groundwater aquifers within sustainable diversion limit (SDL) areas. This limit is established to protect groundwater dependent ecosystems.  Water up to this prescribed maximum extraction limit is recognised as a water asset in the Statement of water assets and water liabilities. Any aquifer volumes greater than this annual extraction limit are considered a contingent water asset for aquifers in the MDB region. However, there is currently not sufficient information available regarding groundwater resources in the region to allow for a volumetric estimate.

Contingent water assets – inter-region claim on water

Inter-region claims on water that can be considered as contingent water assets in the MDB region are a claim on Snowy Hydro to release water to the MDB region and the claim by Grampians Wimmera–Mallee Water in the Glenelg catchment.

Snowy Hydro Claim known as the Required Annual Release (RAR) is estimated considering several input variables at the commencement of the water year.  However, input variables on which the actual entitled release depends include dry inflow sequence volume reduction for the year (a variable to reflect actual inflow during the year) and the volume of water provided by Snowy Hydro to New South Wales irrigators under separate agreements. 

Volumes for these two variables are not known at the beginning of the year so the Snowy claim is a contingent water asset for the MDB region.

Under a Victorian bulk entitlement, Grampians Wimmera–Mallee Water (GWM Water) is able to transfer water to the Wimmera–Mallee supply system, located within the MDB region's boundaries from the Glenelg River:

• upstream of and including Rocklands Reservoir

•  the first and second Wannon creeks upstream of and including the weirs.  

The bulk entitlement requires GWM Water to release water for the purposes of providing a nominal flow for domestic and stock use and other social and environmental purposes in the Glenelg River downstream of Rocklands Reservoir (3,300 ML). The volume that can be diverted to the MDB will therefore depend upon the inflows into the Glenelg River and the requirement to meet the Glenelg compensation flows.  Therefore, the claim is a contingent water asset.

Contingent water liabilities – groundwater entitlements

The water resource plans for groundwater within the MDB region includes entitlements for allocation extraction (in addition to other statutory rights). The water resource plans for groundwater within the MDB region include entitlements that permit the extraction of  water based on seasonal determinations of water availability and subsequently announced allocations applicable to such entitlements, (in addition to other statutory rights). The right to extract water under these entitlements is dependent on sufficient recharge for water availability that determines whether entitlement holders receive 100% allocation. Water availability is outside the control of the management of the region. Therefore, the rights associated with the entitlements for groundwater allocation extraction in the MDB region are considered to be contingent water liabilities. The total volume of the entitlements for allocation extraction in the region is 1,406,832 ML.

Contingent water liabilities – other statutory groundwater rights

The water resource plans for groundwater within the MDB region includes 23,683 ML groundwater basic rights (including land owner basic rights, and mining rights not under water access entitlements). The right to extract water under these basic rights is dependent on sufficient recharge for water availability. In addition, the actual use of water is contingent on when right holders extract water. Therefore, the rights associated with groundwater basic rights in the MDB region are considered to be contingent water liabilities.

Contingent water liabilities – surface water entitlements for direct diversion

The water resource plans for surface water resource plan (WRP) areas within the MDB region includes entitlements that may create a water liability (entitlements for allocation diversion). These entitlements are dependent on sufficient rainfall and subsequent water availability that determines whether entitlement holders receive 100% allocation. Rainfall and subsequent water availability is outside the control of the management of the region. Therefore, the rights associated with the entitlements for surface water allocation diversion in a water resource plan area are considered to be contingent water liabilities. The total volume of the entitlements for allocation diversion in the MDB region is 12,512,627 ML.

Contingent water liabilities – surface water entitlements for direct diversion

The water resource plans for surface water within the MDB region includes 4,777,560 ML surface water access entitlements that give access to unregulated flow, (including supplementary entitlements within regulated systems). The right to divert water under these entitlements is dependent on sufficient depth of water and flow at the source. In addition, the actual use of water is contingent on when entitlement holders divert water. Therefore, the rights associated with these entitlements in the MDB region are considered to be contingent water liabilities.

Contingent water liabilities – other statutory surface water rights

The water resource plans for surface water within the MDB region includes 47,286 ML surface water basic rights (including land owner basic rights, riparian rights, and mining rights not under water access entitlements). The right to divert water under these basic rights is dependent on sufficient depth of water and flow at the source. In addition, the actual use of water is contingent on when right holders divert water. Therefore, the rights associated with surface water basic rights in the MDB region are considered to be contingent water liabilities.