Issue: Water use and allocation in Tumut Shire, Australia

Issue: Water use and allocation in Tumut Shire

Assessment

Not all of the information sought under State of the Environment reporting could be obtained at the time of compiling this Report. Nevertheless, a relatively basic picture of water use within Tumut Shire can still be established.

In this Shire, the nature of the landuses occurring and the availability of water to meet those landuses will effectively govern water usage and allocation. Native vegetation conservation as well as timber production are the predominant land uses. Agriculture is another important land use within the Shire, along with cattle and sheep grazing. There are no data on the water extraction licences and thus it can only be hypothesised that the main usage of water within the Shire is for irrigation purposes.

Urban water use should be the next highest usage of water, but this usage would represent only a small fraction of the overall water consumption within the Shire. Annual per capita per year consumption of 115kL would appear to demonstrate a low reliance on reticulated water supplies for maintenance of gardens due to higher annual rainfall.

Approximately 66% of Tumut Shire falls within unregulated subcatchments, based upon the Stressed Rivers Assessment Reports (DLWC, 2000). One of the eight unregulated subcatchments which falls either partly or wholly Tumut Shire is considered to be under high hydrological stress, the latter implying that in this instance, demand for water already equals or exceeds supply. That subcatchment is the Bomowlee–Brungle–Adjungbilly catchments. One other catchment, the Adelong, has its insufficient data to be assessed in terms of its hydrological stress.Population figures for Tumut Shire show an actual decline in population with an average growth rate of −0.6% over the period 1994–99. Tumut Shire Council reports it has no formal data on the age or life expectancy of the water and sewerage reticulation systems, but has determined both are in a satisfactory condition. The stormwater condition is described as poor but Council has not as yet identified what upgrades of this system will be required in the short to mid term.

The Shire has been in general been a little dry over the period 1997 to 2000 with rainfall in 1997 and 98 some 37% and 17 % respectively less than the average rainfall of 851 mm for Tumut. 1999 was about average.

Most of the ground water within the Shire has been identified as having some salt—that is, with concentrations estimated as being between 1000 and 3000 milligrams per litre. This groundwater can be used for livestock some domestic and industrial uses but has limited potential for irrigation purposes. A band of land in the mid centre to the north of the Shire has been identified as having good quality high yield low salt groundwater with estimated salt concentrations of 0 to 1000 milligrams per litre. This is considered suitable for most uses including potable water and irrigation.

Implications

At present it would appear that most of the water systems in this area are not significantly stressed with the exception of one, possibly two catchments. In their cases depending upon the nature of the users there could be some conflict over the availability of water amongst licence holders, the township and for the environment. However too little is known at this time of the extraction licenses to be able to confirm this.

Recommendations/Objectives to be achieved

Implementation of the NSW Water Management Act will require the construction of a suitable structure around the Act, to ensure that it achieves all of its primary goals. The Act, for example, will require several levels of monitoring and recording of any water demand management. Thus, in establishing that structure, it should be possible to work with the authors of the State of the Environment reports to ensure that common recording of data is achieved for both purposes.

In the case of Tumut Shire, it is recommended that river management strategies be developed as a matter of priority for the Bomowlee–Brungle–Adjungbilly catchments as well as the Adelong Catchment.

Given the lag times often associated with water consumption before environmental and social impacts are understood, work on an overall water management plan will need to commence with those rivers and catchments that are more highly stressed. Given that these water courses are also common with others, work in developing management plans will need to be tied in with the work being done by other Shires.

Background

Survival within an area such as Tumut Shire, requires an adequate supply of water for all needs. This includes human consumption, recreation and agricultural production, as well as conserving and maintaining a healthy aquatic environment. Of particular concern therefore, is the need to provide relief for highly stressed rivers. This has been recognised at a National level and has led to the application of water extraction caps on the Murray-Darling River system.

At a State level, there has been the introduction of the NSW Water Management Act, (effectively introduced in December 2000). This Act has been designed to address over-allocation within stressed rivers in NSW, as well as a number of other water uses, where pressure indicators highlight the need for intervention. This Act will introduce a new system of water licensing, which will include the licensing conditions for Councils in the provision of domestic urban water supplies, as well as any industries within the urban townships. It will also directly impact all persons holding water extraction licences.

The Act will effectively require better-defined water rights and allocations within all of the subcatchments, in order to achieve a more sustainable approach to a limited supply. In the case of Tumut Shire, initial focus will need to be on the highly stressed river schemes/catchments to remove them from the 'highly stressed' category. Similarly there will be a need to address those unresolved rivers.

In some ways, the Act is, within itself, a direct response to the pressure indicators of over-stressed rivers that have occurred within this and other Shires. In Tumut Shire, it could be expected that there will be competing demands for water, initially between those irrigators in the highly stressed catchments, with the downstream irrigators struggling to get their full allocation in drier years. Additionally, the current overstressed nature of one of the catchments will result in conflict with the need to conserve sufficient water to maintain healthy aquatic ecosystems, better known as environmental flows. Thus some form of review of allocations will be necessary. There could also eventually become some conflict between those irrigators and the urban water supplies, in that despite the Shires contraction there will always remain the issue of paramount rights for water particularly during dry periods and in this instance there is a relatively large town to supply.

Indicators used to assess this issue