Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Management and Development - Queensland

Location map of Black River Alluvium

Groundwater Management Unit: Black River Alluvium

Introduction

Management Context:

A priority action for the Black River Alluvium GMU is the review of the Queensland Nickel Agreement Act and the investigation of available options for providing some, or all, of Queensland Nickel's water requirements from Townsville-Thuringowa Water Supply Board bulk supply sources in an effort to maintain the viability and quality of existing groundwater reserves. Recent access to the Townsville Water Board Supply via the Mt. Spec line has resulted in a reduction in industrial extraction of groundwater. However, problems of groundwater supply in the Black River Alluvium GMU are still likely to occur due to the prospect of increased demand for groundwater supplies by both industry and futher urban development. In 1986, it was suggested that a model of the area should be constructed to allow for a better assessment of yield to be made, and to allow for better management of the groundwater resource.

Groundwater extraction within the GMU has affected baseflow in the drainage network. Since the commencement of wellfield pumping in 1974, the lowering of groundwater levels has resulted in significant changes in the hydraulic behaviour of Black and Alice River from primarily effluent in nature, to influent. Present groundwater use within the GMU is approximately 7000 - 8000 ML/annum. An optimal and target extraction for the GMU would be the assessed yield of approximately 6000 ML/annum, which would allow for recovery in the water levels and a return of baseflow in the drainage network.

The protection of both the quantity and quality of the groundwater resource in the Black River Alluvium groundwater management unit is important from an economic as well as environmental perspective. Consequently, aquifer intake areas should be protected against adverse development. However, water quality has slightly improved since pumping commenced from the borefield in 1970, possibly due to the continued extraction and subsequent recharge having a resultant 'flushing' effect on the poorer quality groundwater within the aquifer.

Priority issues

Declining Water Levels

 YES

Salt Water Intrusion

 NO

SALINISATION

Dryland

 NO

Irrigation

 NO

Groundwater

 NO

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

 YES

Management Plans

 NO

Defined Minimum Water Level

 NO

Comment: There is an increasing demand on the groundwater resource of the Black River Alluvium GMU due to the pressure of land development within the area e.g. conversion of grazing pastures to crop irrigation and development of rural/residential subdivisions.

Comments on Management Responses

2020 Management Response:

The estimate of 6000 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 6000 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 Black River Alluvium

Efficacy of the network:

The current monitoring network for the Black River Alluvium groundwater management unit consists of 84 observation bores, with a proposed bi-annual to monthly monitoring frequency.

Continuous monitoring of water levels has occurred since the early 1970's to the present, with water levels monitored monthly by Queensland Nickel Pty Ltd, and approximately 5 to 6 times per year by the Department of Natural Resources. Recently, the frequency of monitoring has decreased to bi-annually over most of the wellfield, with only key bores monitored monthly. The reduced monitoring frequency is feasible due to the defined climate of the area which allows for monitoring prior and after the known wet season, with little change throughout the remainder of the year. The monitoring of the groundwater level assists in the interpretation of wellfield performance and as an indication of aquifer storage. The wellfield, located within the GMU, is overcommitted and it is desirable that the present level of monitoring continue.

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 licenses. 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 Black River Alluvium groundwater management unit aims at maintaining a longterm, sustainable resource and therefore, requires appropriate allocation rates, and the accurate monitoring of groundwater extraction, water level and water quality fluctuations.

Protective management requirements for the Black River Alluvium GMU include:

A reduction in the groundwater extraction to the assessed yield of 6000 ML/yr, which would allow for a recovery in the water levels and a return of baseflow in the drainage network.

Monitoring of the potential demand placed on the groundwater system due to the increase in development and rural/residential subdivisions, in addition to the absence of a reticulated sewerage system. However, the potential for pollution from septic tanks is low if waste management guidelines, with respect to bore location and effluent disposal sites, are adhered to.

Options for monitoring:

A comprehensive Water Management Plan (WMP) is required for the Black River Alluvium groundwater management unit and would be the basis for the implementation of future intra-aquifer trading of groundwater within the GMU. The WMP would involve a desk top study for one individual for a period of approximately 12 months, as extensive data is already available on 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 6000 Ml/yr for sustainable yield was made in 1992 based upon water balance methods and nearly 20 years of wellfield performance. The sustainable yield is inadequate to meet the existing allocation requirements of approximately 10000 Ml/yr.

Sustainable yield:

ML/yr

Threshold year for sustainable year:

1,970 

Abstraction Volume 1996/1997:

7,500 ML 

Current Resource development categorisation:

Estimated Use in 2020

Comment:

Estimated use in 2020:

6,000 ML 

% change from 1996/1997:

-20 

Resource development categorisation:

Estimated in 2050

Comment:

Estimated use in 2050:

6,000 ML 

% change from 1996/1997:

-20 

Resource development categorisation:

 

What assumptions were used in this assessment

Development Potential:

The aquifer within the Black River Alluvium groundwater management unit is stressed and overcommitted and offers no potential for increased development, based upon the assessed sustainable yield and the desired level of resource management. Present groundwater use within the GMU is approximately 7000 - 8000 ML/yr, with the optimal and target extraction for the GMU being the assessed yield of approximately 6000 ML/yr. A reduction in groundwater extraction to the assessed yield would allow for a recovery in the water levels and a return of baseflow in the drainage network.

Estimate of Use:

The estimate of 6000 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 800 observation bores, both private and State owned, are located within the Black River Alluvium GMU. The availability of water level data is high, with continuous water level monitoring in 84 observation bores from the early 1970's to the present. Comprehensive water quality data exists for 76 observation bores within the GMU, with recent analyses from 1990 to the present. Formal use and allocation data is available for areas within the GMU, however the data does not directly pertain to the defined GMU area. The only metered use within the GMU is that of the Queensland Nickel bores, which represent extraction of approximately 70% of the sustainable yield. Comprehesive data exists for wellfield extraction since 1974, with the total Queensland Nickel usage monitored through a single meter, and all contributing bores individually metered.

Current Gaps and Recommendations:

Data Gaps: The Black River Alluvium groundwater management unit is well documented, with a lengthy history of data from water level and water quality monitoring, rainfall gauging stations and surface water gauging stations on Black River. No data gaps exist for the Black River Alluvium GMU.

Recommendations: The current level of monitoring, both water level and water quality, is sufficient and the groundwater resource is well managed. A comprehensive Water Management Plan (WMP) is required to collate the extensive information on the Black River groundwater management unit.

Future Gaps:

A comprehensive Water Management Plan (WMP) is required for the Black River Alluvium groundwater management unit and would be the basis for the implementation of future intra-aquifer trading of groundwater.

Further information

Key

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