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National Water Account 2016

Ord: Water access and use

Almost 90% of the Ord region's water entitlements were for surface water diversion to the Ord River Irrigation Area; less than 1% of the region's water entitlements were for town supply. Cropping commenced in the Stage 2 development area of Goomig Farmlands, but has required limited water supply to date. Most of the individual water use in the region was for agricultural and mining purposes.

 

  

Water rights, entitlements, allocations and restrictions

Irrigation area, Ord region. Source: istock © Mark Higgins

 

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 and abstractions.

The 2016 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 water water accounting reports included in the 2016 Account, 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 2015–16 year have been classified as shown below.

 

Surface water rights

Surface water rights in the Ord region during the 2015–16 year refer to surface water supply for:

  • individual users—37,336 ML
  • urban water system—775 ML
  • irrigation scheme—386,800 ML.

Surface water rights for the urban water system and the irrigation scheme relate to entitlements to divert water for town supply (Wyndham and Lake Argyle Village) and the Ord River Irrigation Area, respectively.

The volumes of surface water allocation and diversion for the 2015–16 year compared with the previous four years are shown in Figure S6. The percentage shows the ratio of diversion to the allocation announcement.

 

Figure S6  Graph of surface water allocations and diversions in the Ord region for the years ending 30 June, from 2012–2016
Figure S6 Surface water allocations and diversions in the Ord region for the years ending 30 June, from 2012–2016

 

Allocations for surface water diversion to the irrigation scheme during the 2015–16 and 2014–15 years are higher than the previous three years (Figure S6). This is attributed to a new licence being issued to the Kimberley Agricultural Investment Pty Ltd in mid-2015 for water diversion to the Goomig Farmlands. The actual diversions to the Ord River Irrigation Area during the 2015–16 year decreased slightly from the previous year; however, this was because metered diversion data were available for water supply to Goomig Farmlands this year. Last year, these data were not available and it was assumed that diversion was equal to the allocation. 

Surface water allocations for individual users and urban water supply during the 2015–16 year remained relatively unchanged. Actual diversions to individual users and town supply were also similar to the previous year, which reflects the similar climate conditions experienced across the region over the last two years.

There were approximately 100 individual users in the region that primarily sourced water from the main Ord River channel, upper Ord River, Dunham River and King River for agricultural and mining purposes. The water supply licences are divided into licence entitlement purposes (Figure S7).

 

Figure S7  Graph of surface water allocation to individual users for each licence purpose
Figure S7 Surface water allocation to individual users for each licence purpose

 

Groundwater rights

Groundwater rights in the Ord region during the 2015–16 year refer to groundwater supply for:

  • individual users—11,589 ML
  • urban water system—2,700 ML.

Groundwater rights for the urban water system relate to entitlements to extract water for town supply (Kununurra and Halls Creek).

The volumes of groundwater water allocation and extraction for the 2015–16 year compared with the previous four years are shown in Figure S8. The percentage shows the ratio of extraction to the allocation announcement.

 

Figure S8  Graph of groundwater allocations and extractions in the Ord region for the years ending 30 June 2012 to 2016
Figure S8 Groundwater allocations and extractions in the Ord region for the years ending 30 June, from 2012–2016

 

Total allocation for groundwater extraction for individual users during the 2015–16 year was similar to the previous year; however, extractions to individual users decreased (Figure S8). This decrease is primarily due to a decrease in water extraction for one of the large mining licences this year.

Allocations and extractions for urban water supply remained relatively unchanged.

There were approximately 40 individual users in the region who primarily sourced water from the Canning–Kimberley groundwater area for the mining sector. The water supply licences are divided into licence entitlement purposes (Figure S9).

 

Figure S9  Graph of groundwater allocation to individual users for each licence purpose
Figure S9 Groundwater allocation to individual users for each licence purpose

 

 

Water market activity

Ord River farming, Ord region. Source: istock © John Carnemolla

 

In Western Australia, water entitlement trades and transfers can only occur within the same water management area (see the Trades and water rights transfers section in the 'Region description').

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 Western Australia Department of Water website.

During the 2015–16 year, no water entitlement trades or transfers occurred in the Ord region.

 

Water use

Purnululu Gorge, Ord region. Source: istock © Photon-photos

 

Economic 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 'Region description'). 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 Surface water rights and Groundwater rights above.

 

Social and cultural benefit

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 'Region description'). This occurs from time to time when maintenance and inspection work on dam infrastructure is required. During the 2015–16 year, maintenance works were conducted at Ivanhoe Crossing downstream of Lake Kununurra from 4–6 November. Consequently, flow in the lower Ord River was reduced during this period (see Figure S11 in the 'Environmental benefit' note).

 

Environmental benefit

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 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 R7 in the 'Region description' 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 S10 shows the required baseflows at the Tarrara Bar station throughout the year; the minimum baseflow is 42 m3/s. Baseflow during the dry season (April–October) is managed almost entirely by water releases from the storages. Figure S10 also shows the frequency, duration, and peak flows required for the wet season flood events in the lower Ord River.

 

Figure S10  Graph of example water provisions for the lower Ord River; required baseflows and wet season flood events are also shown
Figure S10 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 S10 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 2015–16 year is shown in Figure S11.

For all but 3 days of the year (4–6 November 2015), flow in the lower Ord River exceeded the minimum baseflow requirements. This 3-day period of low flow coincided with maintenance works at Ivanhoe Crossing downstream of Lake Kununurra (see Economic, social and cultural benefit above).

Figure S11 also shows that wet season peak flows met most of the requirements outlined in the water provisions. Only the required flood peak that exceeds 425 m3/s was not met.  

 

Figure S11  Graph of flow in the lower Ord River compared with the required flow regime during the 2015–16 year
Figure S11 Flow in the lower Ord River compared with the required flow regime during the 2015–16 year

 

Infrequent wet season flood events are the third component of the flow regime critical for maintaining ecological conditions in the lower Ord River (see Environmental water provisions above). These larger flood events did not occur during the 2015–16 year; however, a flood peak which met the required 1 in 2-year flood event (average daily discharge >750 m3/s) occurred during the previous wet season (see the 2015 Account), and flood peaks which met the required 1 in 4- and 1 in 27-year flood events (average daily discharge >1,400 m3/s and >3,700 m3/s respectively) occurred during the 2013–14 wet season (see the 2014 Account).