Pimpama-Coomera dual reticulation end use study: baseline situational context and post-commission end use prediction

Abstract

The Pimpama Coomera dual reticulation schemes' recycled water supply will be online in mid 2009 and there is much speculation on the actual uptake of recycled water in the region. In an attempt to achieve better estimates on both potable and recycled water end uses within this region, this paper presents a predictive model that utilises a range of input parameters, including: current use in the Gold Coast and the Pimpama Coomera regions at both a bulk billing and end use level; recycled water use at other dual reticulated schemes; and questionnaire survey of residents water source preferences for recycled water for outdoor uses; to name a few. Water end use consumption analysis from the recycled water meter supply indicates that this meter currently only provides 20% of total household use with the majority coming from toilet flushing. However, a range of factors have attributed to this low baseline level with evidence collected in this study indicating that higher recycled water consumption rates will occur once the recycled water line has been commissioned, providing a leniently restricted and guilt free source of water for discretionary outdoor purposes. The weighted amalgamation of a range of baseline adjustment factors assisted in the prediction of post-commissioning end uses for the Pimpama Coomera dual reticulated region. The predictive model indicated that recycled water end uses would account for 53 litres per person per day or 30.6% of total household consumption. The paper concludes with a brief overview of Phase 2 of the study which aims to compare actual post-commission end uses with the baseline situation and prediction, as well as the development of a robust end use model for dual reticulated regions.