Oolloo Dolostone Aquifer water allocation plan

Current plan	Oolloo Dolostone Aquifer water allocation plan 2019 - 2029
Map	Oolloo Dolostone water allocation plan map
Area	5,277km²
Declared	13 November 2019
Duration	10 years
Review	Every 5 years. Read the review report Read the summary of the water resource assessment PDF (5.4 MB)
Expiry	12 November 2029
State of the water resource	State of the Water Resource - Oolloo 2023-24 PDF (869.2 KB)

The plan is applies to all groundwater within the Oolloo Dolostone Aquifer (ODA) and all surface water discharges derived from that aquifer.

It covers 0.39% of the Northern Territory (NT) and 1.60% of the entire Daly Roper Beetaloo water control district (WCD).

Plan objectives

The main objectives are to:

protect the environmental and cultural values of the region
- particularly focusing on groundwater base flows to the Daly River and other groundwater dependent ecosystems
protect existing consumptive beneficial uses of groundwater
enable development of the groundwater resource to realise its potential for use in the region
communicate plan objectives, management principles and resource status
establish a framework for learning and continuous improvement to maximise environmental, social and economic outcomes.

For more information about objectives, strategies and performance indicators, read the ODA water allocation plan 2019 – 2029.

Announced allocations

Read announced allocation (AA) decisions for the current plan area:

Beneficial uses

The beneficial uses of water in a WCD are:

environment
Aboriginal economic development.

The Administrator may set other categories and publish a notice in the Gazette.

The beneficial uses of water and water quality objectives for the Daly Roper Beetaloo WCD were declared on 10 April 2019 in Gazette G15 PDF (264.0 KB).

Water resources

Surface and groundwater are closely connected in the ODA water allocation plan. The dry season flows of the Daly River and its perennial tributaries are dependent on groundwater discharge from the ODA and TLA.

Springs and seepage zones deliver water from the saturated aquifer to the river. The aquifer is recharged by high rainfall during the wet season.

Surface water

The Daly River has a catchment area of 53,000 km2 and has the largest flow of all rivers in the NT. The main tributary is the Katherine River.

Other important tributaries are the Flora, Fergusson, Edith and Douglas rivers. At the start of the plan, there were no large surface water storages on the Daly River or its tributaries.

Allocations

Surface water is allocated to environmental, cultural, rural stock and domestic, and agriculture beneficial uses.

Licences

There are 4 surface water licences for agricultural use subject to the plan with a maximum entitlement of 1,270 ML per year. Water can be taken from the Katherine River at any time of the year.

For this reason, they are managed as part of the ODA consumptive pool and not under surface water extraction policy. They are treated like groundwater licences and managed in a similar way subject to the same announced allocation conditions.

View the licences.

Groundwater

The ODA is part of the Daly geological basin, with Tindall Limestone Foundation at the bottom, and the Jinduckin, Oolloo Dolostone and the Florina formations at the top.

The greatest recharge to the ODA occurs at points where it outcrops (intersects with the surface). Some recharge occurs where the formation is covered by sediment and it also recharges through sinkholes. At points where the Florina formation overlies the ODA, there is no recharge.

Where the ODA receives recharge through sinkholes, there is a risk of contamination.

Groundwater flows through the aquifer from the southeast to the northwest and discharges at low points in the landscape where it outcrops. The greatest discharge from the aquifer is along the middle reaches of the Daly River, around the confluence of the Daly River and Stray Creek.

Allocations

The water allocation plan identifies 3 groundwater management zones where an estimated sustainable yield has been established. This is the amount of water that can be taken while meeting the needs of environmental and cultural values of the water resource.

The table below shows the volume of water available under the estimated sustainable yield from each of the groundwater management zones in the water allocation plan. It also shows the estimated rural stock and domestic use, and the current level of entitlements.

The level of existing entitlements at the time the plan was declared has caused the northern management zone to be over allocated by 990ml per year.

Water management zone	Estimated sustainable yield (ML/year)	Estimated rural stock and domestic use (ML/year)	Existing entitlements (ML/year)
Southern	29800	946	23795
Central	36378	402	17139
Northern	30700	204	31466
Total	97300	1552	72400

Licences

The 40 groundwater extraction licences in the ODA water allocation plan are allocated mostly for agriculture with a small amount of industry beneficial use.

View the licences.

Aboriginal water reserves

The plan establishes a strategic Aboriginal water reserve. The allocation for all groundwater management zones is 19,314ML per year.

At the time of the plan’s release, 9,825ML per year was available.

Recovery of unused water has allowed the central management zone to be fully provisioned and the southern management zone to be 88% provisioned. The other 3,677ML per year remains a notional allocation until such time as water becomes available.