Design and Deployment of Long-term Outdoor Sensornets: Experiences from a Sugar Farm

This paper describes a wireless sensor network that monitored water extraction rate, salinity and water table level. The network collected real-time water quality measurements in order to investigate the impacts of current irrigation practice on the environment, in particular underground water salination. Particular challenges included a large coverage area, a sparse network with mean link distances of 800 metres, and strong diurnal and seasonal effects on communications performance. In response we developed protocols that provided high end-to-end packet delivery rates in a hostile deployment environment. We describe the design, implementation, performance and lessons learned for 18 months of remote operation. The results show that the technology is mature enough for large-scale real-time data collection, and has promise for ensuring large-scale sustainable irrigation.