Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Management and Development - Queensland

Location map of Johnstone River

Groundwater Management Unit: Johnstone River

Introduction

Management Context:

Increases in groundwater use in coastal areas, such as at Mourilyan Harbour, where the Moresby River meets the Pacific Ocean, are at risk of saltwater intrusion and should be monitored.

Priority issues

Declining Water Levels

 NO

Salt Water Intrusion

 YES

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

 NO

Management Plans

 NO

Defined Minimum Water Level

 NO

Comment: Growth in groundwater use in coastal areas, such as at Mourilyan Harbour, where the Moresby River meets the Pacific Ocean, are at risk of saltwater intrusion and should be monitored.

Comments on Management Responses

2020 Management Response:

A forecast use estimate of 1500 Ml/yr in 2020 is based upon current and historical use in the Johnsone River GMU.

2050 Management Response:

A forecast use estimate of 3000 Ml/yr in 2050 is based upon current and historical use in the Johnstone River GMU.

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

Assessment of monitoring in Johnstone River

Efficacy of the network:

Monitoring of bore water levels in the Johnstone River GMU commenced in 1984. Levels were taken approxinmately quarterly with a number of monitoring gaps in 1985/86, 1988/89 and 1995/96. Post 1990 water quality data exists for 130 bores within the GMU. No abstraction data is available as there is no metering of groundwater use in the GMU.

The current monitoring network for the Johnstone River groundwater management unit consists of 50 observation bores with a proposed bi-annual to monthly monitoring frequency.

Data management requirements:

Queensland groundwater monitoring data, including water level and water quality, is stored within the Groundwater Database (GWDB) system. The new GWDB system uses web technology and is available through the department's intranet. The database is managed at a district level, with respect to the collection and entering of water monitoring data; and is accessed statewide.

Protective management:

Management of the groundwater resource of the Johnstone River groundwater management unit aims at maintaining a longterm, sustainable resource and therefore, requires continued monitoring of water level and water quality.

Options for monitoring:

No options for Commenwealth, State, industry or community groups to address data gaps are identified or reported for the Johnstone River 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: 

From investigative drilling it is estimated that 63500 Ml/yr is available within the Johnstone River GMU alluvial aquifers. The claybound nature of sediments and lack of lateral extent of sediments however provide low rates of supply from bores.

Sustainable yield:

ML/yr

Threshold year for sustainable year:

2,100 

Abstraction Volume 1996/1997:

600 ML 

Current Resource development categorisation:

Estimated Use in 2020

Comment:

Estimated use in 2020:

1,500 ML 

% change from 1996/1997:

150 

Resource development categorisation:

Estimated in 2050

Comment:

Estimated use in 2050:

3,000 ML 

% change from 1996/1997:

400 

Resource development categorisation:

 

What assumptions were used in this assessment

Development Potential:

Available groundwater in the Johnstone River GMU significantly outweighs estimated use. Under a high demand scenario a forecast use of only 1200 Ml/yr by 2011 is made. Thus there is little potential for increased demand of groundwater, but high potential for development of the resource.

Estimate of Use:

Estimates of groundwater use in the years 2020 and 2050 in the Johnstone River GMU are based upon historical and current estimates of use.

Data Availability,Gaps and Recommendations

Data Availablility:

Limited monitoring of groundwater levels commenced in 1984 and is proposed to continue in the current monitoring network of 50 observation bores. Post 1990 water quality data exists for

130 bores within the GMU. No abstraction data is collected in the GMU.

Current Gaps and Recommendations:

Data Gaps: A number of groundwater level monitoring gaps occured in 1985/86, 1988/89 and 1995/96. There is also no metering of groundwater use in the GMU.

Recommendations: Monitoring of groundwarter levels and qulaity should continue in the observation network on a bi-annual to monthly frequency. There is however no current need to meter groundwater abstractions.

Future Gaps:

The Johnstone River groundwater resource requires continued groundwater quantity and quality monitoring.

Further information

Key

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