Daly: Water access and use
The following set of notes provides information on water entitlements and water use within the Daly region during the 2015–16 year. Approximately 95% of the region's water entitlements were for individual users, primarily for agricultural purposes. Water use increased during the year, which reflects the poor wet-season rainfall across the region.
Water rights, entitlements, allocations and restrictions
Introduction
This note provides information about the water access rights granted by the Department of Environment and Natural Resources 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 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 Daly region for the 2015–16 year have been classified as shown below.
Surface water rights
Surface water rights in the Daly region during the 2015–16 year refer to surface water supply for:
- individual users—5,855 ML
- urban water system—3,417 ML
- statutory rights—5,369 ML.
Surface water rights for the urban water system relate to entitlements to divert water for town supply (Katherine and Pine Creek). Other statutory rights refers to diversions made by individual users associated with a riparian right.
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 Surface water allocations and diversions in the Daly region for the years ending 30 June, from 2012–2016
Figure S6 shows that surface water allocations for individual users during the 2015–16 year were similar to the previous year. The actual diversions to individual users during the 2015–16 year increased by more than 20% from the previous year, which could be attributed to the poor wet season rainfall that increased users' reliance on water supplied directly from the rivers during the year.
Allocations for urban supply during the 2015–16 year remained unchanged; actual diversions for urban supply were similar to the previous year. The estimated volume of water diverted under other statutory rights during the 2015–16 year also remained unchanged from the previous year.
There were approximately 30 individual users in the region that primarily sourced water for agricultural purposes. Most of the water was sourced from Katherine River, but smaller amounts of water were also sourced from Daly River, Douglas River, Edith River, Stray Creek, and Copperfield Dam. The water supply licences are divided into licence entitlement purposes (Figure S7).
Figure S7 Surface water allocation to individual users for each licence purpose for the 2015–16 year
Groundwater rights
Groundwater rights in the Daly region during the 2015–16 year refer to groundwater supply for:
- individual users—100,924 ML
- urban water system—2,359 ML
- statutory rights—4,280 ML.
Groundwater rights for the urban water system relate to entitlements to extract water for town supply (Katherine). Other statutory rights refers to entitlements to extract water for non-intensive stock and domestic purposes.
The volumes of groundwater allocation and extraction for the 2015–16 year compared with the previous 4 years are shown in Figure S8. The percentage shows the ratio of extraction to the allocation announcement.
Figure S8 Groundwater allocations and extractions in the Daly region for the years ending 30 June, from 2012–2016
Figure S8 shows that groundwater allocations for individual users during the 2015–16 year increased from the previous year. This is primarily attributed to an increase in annual entitlement to a number of licences within the Oolloo aquifer. The actual extractions to individual users during the 2015–16 year also increased compared to the previous year, which could be attributed to the poor wet season rainfall that increased users' reliance on water supplied directly from the aquifers.
Groundwater allocations for urban supply decreased marginally from the previous year; however, extraction for urban supply slightly increased. The estimated volume of water extracted under other statutory rights during the 2015–16 year remained unchanged from the previous year.
There were approximately 125 individual users in the region that primarily sourced water from the Oolloo, Tindall, and Jinduckin aquifers for agricultural purposes. The water supply licences are divided into licence entitlement purposes (Figure S9).
Figure S9 Groundwater allocation to individual users for each licence purpose for the 2015–16 year
Water use
Economic benefit
Surface water and groundwater resources within the Daly region are used for public water supply as well as private water supply for purposes such as agriculture and industry. For a summary of the water volumes allocated for various economic purposes within the region, including the actual volumes abstracted, refer to Surface water rights and Groundwater rights above.
Social and cultural benefit
Aboriginal peoples have never drawn a distinction between the land and the waters that flow over, rest upon, or flow beneath it. The land and waters are equal components of 'country' for which there are on-going responsibilities. This explains to some extent the difficulties for Aboriginal people in quantifying water volumes and values for the purposes of sharing water amongst various users (CSIRO 2009a).
The Daly River region is highly significant to the Aboriginal people and their way of life. It is a source of drinking water, food, and medicines. Many sacred sites have been recorded along the Daly River and its tributaries, and many traditional practices continue to this day. 'Aboriginal people also have customary obligations associated with water including responsibility of keeping the water clean, protecting access to particular places along the river, protecting cultural knowledge, providing cultural education and sharing songs and stories involving the river' (Department of Natural Resources, Environment, the Arts and Sport 2010a).
Cultural benefit in water planning
In the Northern Territory there is a general requirement to establish and provide a water advisory committee for the investigation and analysis of water resources, but there are no specific provisions for public consultation. In practice, the interests of Aboriginal people in water planning are represented by their participation in water-planning processes and through the conduct of studies and assessments that are used to inform the development of water plans.
The Daly River Management Advisory Committee (DRMAC) began as the Daly River Community Reference Group in 2004. The committee was set up to identify and examine the environmental, social, economic, cultural, and heritage values of the region. DRMAC has two subcommittees:
- Daly River Aboriginal Reference Group—the peak body for Aboriginal people in the region
- Katherine Water Advisory Committee—which includes representatives from a wide range of stakeholder groups.
Water allocation plan provisions
The water allocation plans for the Daly region—the Water Allocation Plan: Tindall Limestone Aquifer (Katherine) and the Water Allocation Plan: Oolloo Aquifer (draft)—in their provisions for Aboriginal water, include that they:
- recognise Aboriginal rights and interests in water
- provide for Aboriginal interests through measures to limit extraction of groundwater
- have an underlying premise that the maintenance and protection of environmental flows will ensure the protection of cultural sites and uses
- provide for monitoring and additional studies to improve the information upon which cultural water provisions are based
- commit to taking new information into account in the 5-year review of the plans, particularly the outcomes of monitoring programmes and research findings
- include mechanisms for the creation of water allocations to Aboriginal purposes in particular circumstances.
The water allocation plans recognise the need to provide water to Aboriginal land-owners for economic development purposes, as well as maintain flow conditions, including water quality, to support traditional activities and protect sites of cultural significance. The plans also recognise that cultural water requirements may change due to improved knowledge, research findings, or influencing factors (such as pending native title claims).
Some aspects of cultural water benefit align with environmental water provisions. For example, the protection of the low flows in the Katherine and Daly rivers during the dry season are critical for the survival and function of ecosystems, as well as for maintaining the condition of places that provide physical and spiritual fulfilment to Aboriginal people. Strategies to ensure dry season flows are maintained in these rivers include limiting water allocations for consumptive use on an annual basis, based on current rainfall and recharge conditions (see Environmental water provisions below).
A more detailed description of the cultural water provisions for the Daly region are provided in Part 3 of each of the water allocation plans.
Environmental benefit
Environmental water legislation
The perennial nature of both the Katherine and Daly rivers is maintained throughout the year by groundwater discharge from the Tindall and Oolloo aquifers. These river flows are critical for both environmental purposes and for social and cultural values because they protect a variety of dependent ecosystems and maintain flow at a number of culturally important sites.
Environmental water provisions in the Daly region are currently only defined for the Tindall aquifer. These provisions are outlined in the Water Allocation Plan: Tindall Limestone Aquifer (Katherine) and are based on findings in the Department of Infrastructure, Planning and Environment (2004) report. The report outlines minimum streamflows required to maintain current ecological conditions in the region.
There are no statutory requirements for environmental water provisions from the Oolloo aquifer yet as the water allocation plan is still at draft stage.
Further information on the Daly region's environmental water legislation is provided in the Environmental water management section of the 'Region description'.
Environmental water provisions
Environmental water provisions have been established for the Tindall aquifer for three different scenarios: very dry, dry, and normal-to-wet years. These scenarios are defined based on a model-predicted flow rate on 1 November along the Katherine River at Railway Bridge (Station G8140001: see Figure R5 in the 'Region description' for location), as shown in Figure S10. The flow in the Katherine River on 1 November is predicted prior to the start of the region's water year (1 May), and is based on the previous wet season rainfall.
The late dry season flow at Katherine River is equated to an annual groundwater discharge volume from the Tindall aquifer into the river (Figure S10). The annual allocations from the aquifer, which are announced on 1 May each year, are based on this volume. The importance of groundwater discharge to environmental values in the region is reflected in the increased proportion of discharge reserved for environmental benefit during dry years (Figure S10). The remainder of the annual groundwater discharge is allocated for extraction for consumptive use.
Figure S10 Environmental water provisions for the Tindall aquifer
A more detailed description of the environmental water provisions for the Tindall aquifer is provided in Part 4 of the Water Allocation Plan: Tindall Limestone Aquifer (Katherine).
Environmental water outcomes
Predicted streamflow on 1 November 2015 along Katherine River at the Railway Bridge (Station G8140001) was 1.98 m3/s. This means the environmental water provisions for the 2015–16 year for the Tindall aquifer were based on a normal-to-wet year classification and a predicted annual groundwater discharge of 111,383 ML (Figure S11).
According to the environmental water provisions, 70% of the total annual groundwater discharge from the Tindall aquifer during the 2015–16 year is reserved for environmental benefit and 30% for consumptive use (Figure S11). The allocations for consumptive use from the Tindall aquifer were announced at the start of the Daly region's water year (1 May 2015).
Figure S11 Environmental water outcomes for the 2015–16 year
Observed flow along the Katherine River at 1 November 2015 was approximately 1.14 m3/s. This was lower than predicted (Figure S11).
Based on the observed flow along the Katherine River, groundwater discharge from the Tindall aquifer into the river was approximately 60,000 ML. If consumptive users had extracted their full allocated volume from the aquifer (33,383 ML) during the 2015–16 year, the discharge volume reserved for environmental benefit would only have been about 40% of the total groundwater discharge. This is lower than the required 70%; however, less than 25% of the allocated volume (approximately 7,300 ML: see Figure S5 in the 'Water stores' note) was actually taken from the Tindall aquifer by users during the 2015–16 year. This means that more than 70% of the year's groundwater discharge was for environmental benefit.