The most cost-effective ways to maintain public open space with less water: Perth case study

Abstract

Local governments in Perth, Western Australia, use groundwater to irrigate high value public open space. Due to a sustained decline in rainfall current groundwater extraction rates are unsustainable and are set to be reduced. We investigate the cost-effectiveness of different water efficiency improvement technology solutions. There is significant variation in the cost-effectiveness of different techniques, with the cost of water saved varying from a low of AUD 0.27 per kilolitre to as high as AUD 13.49 per kilolitre. In most cases the water efficiency solutions considered delivered water savings for less than the cost of the backstop technique – scheme water – which costs AUD 2.09 per kilolitre. For the case study area we find that 5, 10, and 15% saving in the volume of water used to irrigate public open space can be achieved for average per kilolitre water costs of: AUD 0.38, AUD 0.43, and AUD 0.62, respectively.

Keywords:

• Cost-effectiveness
• irrigation efficiency improvement
• public open space
• reduced groundwater availability

Acknowledgements

The authors acknowledge the support of the Department of Water in undertaking this study and the significant contribution of City of Nedlands Parks staff who provided relevant input and data to undertake this study. The authors are also grateful to Parks staff from the Cities of Joondalup, Stirling and Subiaco.

Notes

1. For the purposes of this study, POS refers to the freely accessible areas that support functions of recreation, relaxation, socialisation and informal play (recreation spaces), organised sporting activities (sport spaces), and environmental protection (nature spaces) (Department of Sports and Recreation [DSR] 2012).