Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Management and Development - Queensland

Location map of Burdekin River Irrigation Area (Right Bank)

Groundwater Management Unit: Burdekin River Irrigation Area (Right Bank)

Introduction

Management Context:

The longterm viability of irrigation within the GMU is threatened by large areas of shallow, relatively saline groundwater that exist within the GMU. Potential exists for serious hydrosalinity problems to develop if irrigation development is not carefully planned with respect to the hydrology of the area. Saline scald areas also exist within the GMU, and are thought to form active discharge zones during periods of sustained rainfall. Prolonged irrigated cropping in these areas would contribute towards a substantial change in hydrology such as waterlogging and water table related salinisation problems. Dewatering is presently being conducted in some areas of the GMU and intends to continue through the pre- irrigation phase and any subsequent irrigation development.

Saltwater intrusion is another potential water quality issue for the GMU which may develop as a result of dewatering in times of peak water demand. There is also potential for pesticide and herbicide contamination, of both surface and groundwater resources, to occur with the introduction of intense agricultural activity.

Priority issues

Declining Water Levels

 NO

Salt Water Intrusion

 YES

SALINISATION

Dryland

 NO

Irrigation

 YES

Groundwater

 YES

Surface Water

 NO

Urban

 NO

Point Source Pollution

 NO

Diffuse Source Pollution

 NO

Subsidence

 NO

Artificial Recharge (ML/yr)

 no data

Ecosystems Protection

 NO

Surface Water Interaction

 NO

Management Plans

 NO

Defined Minimum Water Level

 NO

Comment: A shallow saline water table is a priority issue within the Burdekin River Irrigation Area (Right Bank) GMU.

Comments on Management Responses

2020 Management Response:

The estimate of 20000 Ml/yr for the forecast use for the year 2020 is based upon the GMU's assessed sustainable yield, development potential and the desired level of resource management.

2050 Management Response:

The estimate of 20000 Ml/yr for the forecast use for the year 2050 is based upon the GMU's assessed sustainable yield, development potential and the desired level of resource management.

See QLD Water Resources Assessment 2000 Technical Report for a review of management responses.

Assessment of monitoring in Burdekin River Irrigation Area (Right Bank)

Efficacy of the network:

The current monitoring network for the Burdekin River Irrigation Area (Right Bank) GMU consists of 342 observation bores, with a proposed bi-monthly to monthly monitoring frequency. The existing groundwater level and water quality network requires expansion to assist in more accurately defining the extent of the shallow water table.

A long term dewatering trial is presently being conducted in a section of the GMU and aims to continue through the pre-irrigation phase and any subsequent irrigation development. As part of this trial, five production bores have been established to depths of up to 30 m in fractured rock, in addition to 30 observation bores to assist in monitoring the trial results. Pumping commenced in May 1995, and since that time there has been a gradual development of a pumping depression and a change in the groundwater flow towards the pumping bores.

Data management requirements:

Queensland groundwater monitoring data, both water level and water quality, is stored within the Groundwater Database (GWDB) system. The new system is based on web technology and is available through the Department's intranet. Allocation and use data is obtained through the Water Entitlements Registration Database (WERD) which is an electronic database for water license details. Both databases are managed locally at district level, with respect to the collection and entering of water monitoring, allocation and use data; and are accessed statewide.

Protective management:

Management of the groundwater resource of the Burdekin River Irrigation Area (Right Bank) groundwater management unit aims at maintaining a longterm, sustainable resource. Coastal aquifers prone to salt water intrusion, such as those of the Burdekin River Irrigation Area (Right Bank) GMU, remain capable of yielding a sustainable source of freshwater if protective and flexible management practices are implemented. Protective management requirements for the Burdekin River Irrigation Area GMU include:

expansion of the existing groundwater level and water quality monitoring network to assist in more accurately defining the extent of the shallow water table;

conjunctive use of surface and groundwater in order to control groundwater levels through controlling rises in groundwater levels, with the longterm management strategy involving pumping groundwater into distribution channels;

maintenance of the Burdekin River, with respect to environmental need and environmental flow requirements.

Options for monitoring:

Options for Commonwealth and State agencies to address data and information gaps include:

expansion of the existing groundwater level and water quality monitoring network to assist in more accurately defining the extent of the shallow water table.

carrying out further detailed investigation in order to improve the understanding of the hydrogeology and the likely response to changes in landuse within the GMU

See QLD Water Resources Assessment 2000 Technical Report for a review of monitoring.

What is the estimated demand for groundwater?

Sustainable Yield

Comment about sustainable yield figure: 

An assessment of 20000 Ml/yr for sustainable yield was made in 2000 based upon water balance methods.

Sustainable yield:

ML/yr

Threshold year for sustainable year:

1,990 

Abstraction Volume 1996/1997:

20,000 ML 

Current Resource development categorisation:

Estimated Use in 2020

Comment:

Estimated use in 2020:

20,000 ML 

% change from 1996/1997:

0 

Resource development categorisation:

Estimated in 2050

Comment:

Estimated use in 2050:

20,000 ML 

% change from 1996/1997:

0 

Resource development categorisation:

 

What assumptions were used in this assessment

Development Potential:

The groundwater resources of the BRIA (Right Bank) groundwater management unit are not expected to sustain any significant increase in development due to relatively poor quality and highly variable yield. Groundwater extraction is required in areas of the GMU to induce decline in the shallow water table to avoid water logging and related water table salinisation problems. The introduction of intense agricultural activity within the GMU will have major impacts upon the groundwater resource, such as:

increased recharge resulting from clearing, introduction of irrigated agriculture and leakage from supply channels;

increase in subsurface flow resulting in mobilisation of salts stored naturally in the soil profile;

the potential leaching of chemical residues into the groundwater system due to the introduction of cultivation and application of fertilisers and pesticides.

The shallow water table and accompanying potential salinity hazards may reduce the designated area that is feasible to irrigate.

Estimate of Use:

The estimate of 20000 Ml/yr for the forecast use for the years 2020 and 2050 is based upon the GMU's assessed sustainable yield, development potential and the desired level of resource management.

Data Availability,Gaps and Recommendations

Data Availablility:

In excess of 900 observation bores, both private and State owned, are located within the BRIA (Right Bank) GMU. The availability of water level data is high, with water level monitoring conducted in 342 observation bores, some from 1975 to the present, on an approximatley bi- monthly basis. Comprehensive water quality data exists for 442 observation bores within the GMU, with recent analyses to 1998.

Current Gaps and Recommendations:

Data Gaps: Additional data is required to determine the hydraulic characteristics and extent of the aquifer.

Recommendations: Expand/increase the existing groundwater level and quality monitoring network to assist in more accurately defining the extent of shallow water tables. Further detailed geological investigation is required to improve the understanding of the hydrogeology and the likely response to changes in landuse within the GMU.

Future Gaps:

The complexity of the geology within the GMU requires further detailed investigation in order to improve the understanding of the hydrogeology and the likely response to changes in landuse within the GMU.

Further information

Key

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