Ord
Water access and use

Water rights, entitlements, allocations and restrictions

a. Introduction

This note provides information about the water access rights granted by jurisdictions to the users of the region's water resources and the associated allocation announcements, diversions, adjustments and forfeitures.

The 2013 Account acknowledges that the legislative water resource management frameworks relating to Australian water rights vary greatly across jurisdictions, sometimes making comparisons difficult. To facilitate meaningful comparisons between the 2013 water accounting reports, the Bureau of Meteorology has developed and applied an accounting concept to classify and report water entitlements within a water asset/water liability framework.

According to that framework, water rights for the Ord region for the 2012–13 year have been classified as shown in tables 1 and 2.


b. Surface water rights

Table 1 summarises the surface water rights for the Ord region, including surface water allocations, abstractions, adjustments and forfeitures during the 2012–13 year.

The total water allocation announcement is assumed to equal 100% of the annual entitlement.

 

Table 1  Summarised information on surface water rights, allocations, abstractions, adjustments and forfeitures for the Ord region during the 2012–13 year

Water rights (at 30 June 2013)

Water allocation (2012–13)

Water abstraction (2012–13)

Adjustment and forfeiture (2012–13)

Account line item

Volume (ML)

Account line item

Volume (ML)

Account line item

Volume (ML)

Account line item

Volume (ML)

32.3 Surface water access entitlement for allocated diversions

377,080

21.1

38,205

17.11

27,298

13.1

14,446

21.2

775

17.12

427

13.2

348

21.3

338,100

17.13

153,697

13.3

195,932

Total

377,080

 

377,080

 

181,422

 

210,726


The actual abstraction of allocated water during the 2012–13 year compared to the 2011–12 year is shown in Figure 1. The percentage shows the ratio of actual water abstraction to allocation announcements.


Figure 1  Comparsion of surface water allocations and abstractions in the 2012–13 year to the 2011–12 year
Figure 1  Comparsion of surface water allocations and abstractions in the 2012–13 year to the 2011–12 year


Figure 1 shows that the allocation announcements for surface water diversion during the 2012–13 year were relatively similar to last year. Surface water abstractions to individual users during the 2012–13 year increased compared to the 2011–12 year, but abstractions to the urban water system and the irrigation scheme remained relatively unchanged. 

More information about the items presented in Table 1 is provided in the linked line item notes.


c. Groundwater rights

Table 2 summarises the groundwater rights for the Ord region, including groundwater allocations, abstractions, adjustments and forfeitures during the 2012–13 year.

The total water allocation announcement is assumed to equal 100% of the annual entitlement.

 

Table 2  Summarised information on groundwater rights, allocations, abstractions, adjustments and forfeitures for the Ord region during the 2012–13 year

Water rights (at 30 June 2013)

Water allocation (2012–13)

Water abstraction (2012–13)

Adjustment and forfeiture (2012–13)

Account line item

Volume (ML)

Account line item

Volume (ML)

Account line item

Volume (ML)

Account line item

Volume (ML)

33.3 Groundwater access entitlement for allocated extractions

14,180

22.1

11,480

18.11

9,018

14.1

2,467

22.2

2,700

18.12

1,746

14.2

954

Total

14,180

 

14,180

 

10,764

 

3,421


The actual abstraction of allocated water during the 2012–13 year compared to the 2011–12 year is shown in Figure 2. The percentage shows the ratio of actual water abstraction to allocation announcements.


Figure 2  Comparison of groundwater allocations and abstractions in the 2012–13 year to the 2011–12 year
Figure 2  Comparison of groundwater allocations and abstractions in the 2012–13 year to the 2011–12 year


Figure 2 shows that the allocation announcements for groundwater extraction during the 2012–13 year remained relatively unchanged from last year. Allocation extractions to individual users during the 2012–13 year decreased by approximately 20% from the 2011–12 year; however, this was because metered abstraction data were available for one of the large mining licences this year. Last year, these data were not available and it was assumed that abstraction was equal to the annual announcement. Extractions to the urban water system during the 2012–13 year were similar to the comparison year.

More information about the items presented in Table 2 is provided in the linked line item notes.

 

d. Water restrictions

There were no water restrictions in the Ord region during the 2012–13 year.

Water market activity

Table 3 shows the trades and transfers of surface water licence entitlements that occurred in the Ord region during the 2012–13 year. All of these entitlement transfers occurred within the same surface water management area (see the Trades and water rights transfers section in the 'Contextual information'). No trades of groundwater licence entitlements occurred during the 2012–13 year.

 

Table 3  Information on the surface water trade in the Ord region during the 2012–13 year

Transaction type

Number of licences

Volume

(ML)

Transfer

3

1,139

Agreement

1

1,400

Total

4

2,539

 

In Western Australia trades and transfers are defined as water entitlements that are permanently transferred to another licence holder. A trade is where the new licence holder will abstract water from a different location; a transfer is where water abstraction will occur from the same location. An agreement is a temporary transfer of a licence water entitlement to another licence holder (also referred to as a temporary transaction).

More information on water entitlement transactions can be found on the Department of Water (Western Australia) website.

Water use

Economic, social and cultural benefit

Water is released from Lake Argyle for hydroelectric generation. The power station requires enough water released to enable at least 210 gigawatt hours/year to be generated (see the Operating rules and constraints section in the 'Contextual information'). To generate this power commitment, about 2,100,000 ML/year must be released from Lake Argyle. The water released has the dual purpose of administering water access entitlements downstream, including bulk irrigation in the Ord River Irrigation Area, and other agricultural, commercial, industrial, and mining activities.

For a summary of the water volumes allocated for various economic purposes within the Ord region, including the actual volumes abstracted, refer to line items 32.3 Surface water access entitlement for allocated diversions and 33.3 Groundwater access entitlement for allocated extractions.

Water provided for the environment to maintain specific levels in the lower Ord River has the dual purpose of satisfying ecological requirements and allowing access to boats for recreational purposes.

Periods of low flow in the lower Ord River are administered to support traditional hunting and fishing activities (see the Cultural water management section in the 'Contextual information'). This occurs from time to time when maintenance and inspection work on dam infrastructure is required. During the 2012–13 year, the hydroelectric power station had a shutdown between 22 April–1 May 2013. Consequently, flow in the lower Ord River was reduced during this period (see Figure 4 in the Environmental benefit note).

Environmental benefit

Introduction

Water for environmental benefit in the Ord region is provided according to the following environmental water management scenario: planned partly regulated (or 'supplemented') surface water.


Environmental water legislation

Environmental water provisions in the Ord region are defined for the lower Ord River (downstream of Lake Argyle). These provisions are outlined in the Ord Surface Water Allocation Plan.

The plan outlines a flow regime required to maintain current ecological conditions in the lower Ord River, including:

  • populations of fish and macro invertebrates
  • vegetation community structure
  • water quality
  • channel morphology.

The plan recognises that different parts of the flow regime, such as low, high and overbank flows have different ecological functions. The different components of the flow regime, which reflect the seasonality of the river, are important to the ecology of the lower Ord River.


Environmental water provisions

Environmental water provisions for the lower Ord River comprise three components:

  1. baseflow (minimum flow rate)
  2. wet season flood events
  3. infrequent (high magnitude) wet season flood events.

All three components of the flow regime are critical for maintaining ecological conditions in the Ord River. The required flow regimes are maintained from a combination of water releases from Lake Argyle and Lake Kununurra, and unregulated catchment inflow.

The Water Corporation of Western Australia operates the two storages and manages the releases of water. The Department of Water monitors the flow along the lower Ord River at the Tarrara Bar gauging station (Station 809339—see Figure P7 in the Contextual information for location) to ensure the required flow is being maintained throughout the year.

The required minimum baseflow in the lower Ord River varies between the wet and dry seasons. Figure 3 shows the required baseflows at the Tarrara Bar station throughout the year. Baseflow during the dry season (April–October) is managed almost entirely by water releases from the storages. Figure 3 also shows the frequency, duration, and peak flows required for the wet season flood events in the lower Ord River.


Figure 3  Example water provisions for the lower Ord River; required baseflows and wet season flood events are also shown
Figure 3  Example water provisions for the lower Ord River; required baseflows and wet season flood events are also shown


The infrequent wet season flood events occur as a result of runoff from the catchment downstream of Lake Argyle and cannot be managed by water releases from the storages. The return intervals for these flood events are greater than 1 in 2 years, so this component of the required flow regime is difficult to evaluate on an annual basis. These flood events are not shown in Figure 3 above.

A more detailed description of the environmental water provisions for the lower Ord River are provided in Chapter 4 of the Ord Surface Water Allocation Plan, including variations to the flow regimes for low rainfall years (determined by water levels in Lake Argyle).


Environmental water outcomes

The mean daily flow at the Tarrara Bar gauging station along the lower Ord River during the 2012–13 year is shown in Figure 4.

For the majority of the year, flow in the lower Ord River exceeded the minimum baseflow requirements. During the wet season, flow exceeded a mean daily flow of 100 m3/s for more than 18 days and there were at least four flood peaks that exceeded 125 m3/s (as required in the water provisions).

Figure 4, however, also shows that during the 2012–13 year:

  • Flow in the lower Ord River fell below the minimum baseflow threshold for six days between 25–30 April. This was due to dam maintenance work being carried out during this period (see the Economic, social and cultural benefit note).
  • Flow exceeded 125 m3/s for a duration of nine days instead of the required ten days.
  • Only one flood exceeded 200 m3/s (for a duration of two days) instead of the required two floods for a total duration of five days.
  • No floods exceeded 425 m3/s.


Figure 4  Graph of the daily flow in the lower Ord River compared with the required flow regime during the 2012–13 year
Figure 4  Graph of the daily flow in the lower Ord River compared with the required flow regime during the 2012–13 year


The 4-month period between January and April is usually when the majority of the flood events occur in the lower Ord River, primarily due to unregulated catchment inflow (not storage releases); however, during the 2012–13 year, flow during this period was well below the long-term average across the entire Ord region (see Water overview). These flow conditions are attributed to the below average rainfall observed throughout the region during the year (see Climate overview), particularly during the middle of the wet season (January–March).