Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Management and Development - Queensland

Location map of Alligator Creek

Groundwater Management Unit: Alligator Creek

Introduction

Management Context:

The protection of both the quantity and quality of the groundwater resource in the Alligator Creek groundwater management unit is important from an economic as well as environmental perspective. Further subdivisions of land within the Alligator Creek GMU are likely to result in increased demand placed upon water resources and potential overdevelopment of both surface and groundwater supplies. Aquifer intake areas should be protected against adverse development.

Another priority issue for the Alligator Creek GMU is the potential for saltwater contamination of the lower reaches of the aquifer, as the tidal influence is only approximately 4.0 km downstream of the Bruce Highway. Whilst conductivity remains low in this area, the water is extremely hard, yet still appears to be suitable for all purposes.

Priority issues

Declining Water Levels

 YES

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

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 Alligator Creek

Efficacy of the network:

The current monitoring network within the Alligator Creek GMU consists of 1 observation bore.

Water levels have been monitored at this one location since 1980, with gaps in the water level data between the years of 1984 and 1988. The monitoring frequency varies between two to six measurements of water levels per year. The existing monitoring network should be increased, from

1 to up to 8 observation bores, inconjunction with a comprehensive water level and water quality monitoring program, to enhance the resource management of the Alligator Creek groundwater management unit.

The establishment of an adequate information system would allow for the assessment of both water level and water quality fluctuations, and the detection of both water level and water quality trends in the Alligator Creek GMU.

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 Alligator Creek groundwater management unit aims at maintaining a longterm, sustainable resource and therefore, requires the accurate monitoring of water level and water quality fluctuations.

Protective management requirements for the Alligator Creek GMU include:

Monitoring of the increasing demand placed upon water resources, due to the increase in development of rural residential subdivisions, and preventing the potential overdevelopment of surface and groundwater supplies.

Increasing the monitoring network and establishing an adequate information system in an effort to identify and appropriately manage the threat of salt water intrusion and declining water levels by allowing the assessment of both water level and water quality fluctuations, and the detection of both water level and water quality trends from collected data. Increased monitoring within the GMU will also assist in the assessment of local activities and their impact on the groundwater resource of the GMU, such as the possible impact upon stream flow and interception of down valley flow in drought times, due to the Mt Elliott estate obtaining a water supply upstream of the GMU.

Options for monitoring:

The establishment of an adequate information system is required for the assessment of both water level and water quality fluctuations, and the detection of both water level and water quality trends in the Alligator Creek GMU. The existing monitoring network should therefore be increased, from 1 to up to 8 observation bores, inconjunction with a comprehensive water level and water quality monitoring program to enhance the resource management of the Alligator Creek groundwater management unit.

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 of the Alligator Creek GMU was made in 2000 based upon local landholders knowledge of historical water level fluctuations and an estimate of abstraction.

Sustainable yield:

ML/yr

Threshold year for sustainable year:

2,002 

Abstraction Volume 1996/1997:

6,000 ML 

Current Resource development categorisation:

Estimated Use in 2020

Comment:

Estimated use in 2020:

6,000 ML 

% change from 1996/1997:

0 

Resource development categorisation:

Estimated in 2050

Comment:

Estimated use in 2050:

6,000 ML 

% change from 1996/1997:

0 

Resource development categorisation:

 

What assumptions were used in this assessment

Development Potential:

The development potential for the Alligator Creek groundwater management unit is low, as determined by the sustainable yield and the desired level of resource management. The demand on water resources is expected to increase with further land subdivisions in the Alligator Creek GMU, which may result in overdevelopment of both surface and groundwater resources. Although essentially for domestic supply, there is an increasing demand placed upon the groundwater resource for the purpose of irrigation of commercial crops, such as tropical fruit.

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:

The availability of water level data is low, with water level monitoring restricted to 1 observation bore within the Alligator Creek GMU. Water level data at this location extends from 1980 through to the present, with data gaps between the years of 1984 and 1988. No water quality data exists for the Alligator Creek GMU.

Current Gaps and Recommendations:

Data Gaps: Water level data gaps exist between the years of 1984 and 1988. Water level data is available only for one location within the Alligator Creek GMU. No water quality data exists for the Alligator Creek GMU. Formal use and allocation data is not available.

Recommendations: Increasing the existing monitoring network, from

1 to up to 8 observations bores, inconjunction with a comprehensive water level and water quality monitoring program will enhance the resource management of the Alligator Creek groundwater management unit by establishing an information system to allow for the assessment of both water level and water quality fluctuations, and the detection of both water level and water quality trends in the GMU.

Future Gaps:

The establishment of an adequate information system would allow for the assessment of both water level and water quality fluctuations, and the detection of both water level and water quality trends in the Alligator Creek GMU. Increasing the existing monitoring network, from 1 to up to 8 observation bores, inconjunction with a comprehensive water level and water quality monitoring program, would enhance the resource management of the Alligator Creek groundwater management unit.

Further information

Key

   Links to an another web site
   Opens a pop-up window