Water supply planning and influences on residential water use : a study of the Hobart water supply system

This report describes the historical, political and administrative aspects of the provision of water for the Hobart Metropolitan Area, and a short term study of environmental influences on residential water use. The study was commenced because of concern raised in Hobart about the continued provision of adequate water for the area. A decision was to be made to either augment, or to introduce measures which would ensure more efficient use of, the existing supply. It was felt that the consideration of demand management techniques in the provision of water for Hobart was limited due to, mainly, the lack of understanding of the factors influencing water use. A study was conducted on the existing water consumption data of the various supply authorities in the Hobart area. The available data were found unsuitable for such study - being either too limited, for too long intervals of time, or such that the residential component of water use could not be separated from the other components. These results indicated the need for a short term programme, consisting of reading household meters and the collection of household and associated data, in selected study areas, to demonstrate the type of data required to assist the decision making process involved in the provision of more water versus more efficient use of existing supplies. The data collected were processed and analysed with the aid of a standard computer program. It was not possible to make definite conclusions from the result of the analysis regarding the effects of any of the factors on residential water use. Within the limited scope of the study only the weather conditions, number of persons per household and garden water use habits were indicated to be major influences. Much more extensive, long-term data are required for making a definite conclusion of accurate assessment of the influence of these and the other factors on residential water use. In the absence of adequate technical information on water use and modifying factors, it became evident that historical, political and administrative aspects have played an important role in the planning, management and provision of water for Hobart. It was found that the relative ease of provision of Hobart's water has greatly influenced the general approach to planning and management of the supply and the attitudes of the consumers with regard to the use of water. Furthermore, it was found that political considerations have often prevailed over any technical or even economical consideration in the final decisions regarding the development of the supply. Finally, it is felt that the division of administrative responsibility for provision of water among the various authorities, the lack of water consumption data and that of other tech-nical information have made an effective planning and management of water supply in Hobart extremely difficult