Introduction

As resource demands and pressure increases so to do the requirements of both management and information needs. Outlined below are the key issues facing the region as determined by the State / Territory water management agency.

What is the estimated demand for surface water in Coal River?

How was this assessment undertaken in the Coal River Surface Water Management Area?

Development Potential:

The principle data source currently available to the State for use in assessing development potential for irrigation is farm dam growth. Unfortunately this information could not be broken down to a surface water management area (SWMA) level but was only available on a State scale. Due to the coarsness of this information it was not considered to be particularly suitable as a tool at SWMA level for estimating growth. The other source of information available was from a joint study project by the Australian Academy of Technological Science and Engineering and the Insitution of Engineers Australia titled "Water and the Australian Economy April 1999"(ISBN 1875618 50 3). This report arrived at a growth rate of 1.3 percent for Tasmania. It was found that the information available on farm dam growth inn the State and some landholder estimates in relation to theire future irrigation requirements generally supported this growth. Currently in the State there are a number of proposals for large storage development and some interbasin diversions. For the Coal, there is currently a proposal to utilise water in the SEIS from the Derwent River. Water from the Derwent is proposed to come from the Hobart Water Authority pipeline to a saddle dam and then gravitation to Stage 2 of the SEIS). This will improve the overall reliability of supply for the SEIS and is expected to commence in the Augustyear 2000. It was assumed that domestic demand on a State and SWMA basis would remain static. Population growth has not been predicted to 2050 and indeed ABS actually forcast a negative growth. Industrial growth cannot be forecast accurately either at a State or SWMA level with any degree of assurity at this stage without further studies. It is envisaged that growth will occur in the State but reliable data is not available to predict this with any degree of accuracy.

Estimated Use:

Developed potential for use was assessed on the basis of a 1.3 percent growth rate applied to the use estimate for 1996/97.

Developed potential for use was assessed on the basis of a 1.3 percent growth rate applied to the use estimate for 1996/97. Reliability of the 1.3 % growth is unknown.

Developed Yield:

Details on potential infrastructure development were not available for use in the Audit. However for the purposes of the Audit, the assumption adopted was that infrastructure could be developed to meet the demand forecast. Hence developed yield for years 2020 and 2050 were taken as the forecast use rounded up to the next 1000 megalitres.

Management goals and objectives:

1 Essential needs of town water supplies and stock and domestic needs, 2 Ecosystem needs,

3 Supply of water for irrigation and non essential town supply purposes eg parks and gardens,

See TAS Water Resources Assessment 2000 Report and Water Resources Assessment 2000 Technical Report for comment on methods and assumptions.

Comments on Management Responses in the Coal River Surface Water Management Area

Current Management Response:

Desired (Current) Management Response:

2020 Management Response:

See database

2050 Management Response:

See database

See TAS Water Resources Assessment 2000 Report for comment on management responses.

Assessment of Monitoring

Efficacy of the network:

This SWMA like many others ins the State has a resoursing problem in relation to providing good quality and long term data.

Data management requirements:

Information from streamflow and water quality monitoring stations will need to be put into streamflow database (Hydro) and water usage information into water management data base (WIMS). These two systems need to be linked to GIS to provide a better management focus for this data.

Protective management:

Not applicable

Options for monitoring:

There is a clear need for Commonwealth assistance under some form of partnership arrangement with the State to provide resources to address information gaps part. This would better position the State for providing better information for future Audits.

See TAS Water Resources Assessment 2000 Technical Report for an assessment of monitoring

Data Availability, Gaps and Recommendations

Data Availability:

There were 4 stream gauging stations in the SWMA with varying periods of records ranging fom 11 years to 29 years (Coal River at Baden being the longest).

The annual surface water use for the SWMA is 1814 megalitres. This is a reasonable estimate as the majority of water in the area is used is by the South East Irrigation Scheme which is metered.

Current Gaps and Recommendations:

Data Gaps: The following have been identified as gaps in data:

1. Base line water quality information has only been gathered since 1995. This needs to be continued to provide a long term picture on water quality

2. There is only one long term water quality measuring station in the SWMA. The density of the information needed to be gathered requires reviewing.

3. State of River (SOR) reports to report on the environmental integrity of rivers and streams in the area.

4. Assumptions used in Review 85 for determining divertible yield

5. Information on environmental water requirements was approximate due to Audit needs for a very quick estimate.These will be refined by current studies to be finalised over next two years.

Recommendations:

1. Review baseline water quality network

2. Continue SOR reporting on a 10 year report ing basis.

3. Re estimate divertible yield for the SWMA.

Future Gaps:

To properly estimate future demands would require very detailed analysis and take considerable time. Such estimates would be subject to changes in market forces, community expectations and government policy change.

From a water resource development viewpoint, Tasmania is commencing the start of another growth period with considerable interest in irrigation expansion and storage development. Unfortunately estimates of this likely growth could not be made in time to meet Audit deadlines.

All estimates of developed yield and growth provided in this report are very approximate and are not generally considered to be satisfactory at this stage for long term planning for the State. For the purpose of long term planning a more rigorous estimate for long term growth would have to be made.

See TAS Water Resources Assessment 2000 Technical Report for a review of data availability,gaps and recommendations.

Further information

• Tasmania Water Resources Assessment 2000 Technical Report
• Link to data available for download on the Surface Water Management Areas
• Link to the Map Maker to make a map using this information.