Introduction
Cairns is a coastal city in tropical Far North Queensland. The local authority, Cairns Regional Council (CRC), serves an area of 4129 km2 and a population of approximately 165,000 – which has increased by 37,000 since 2002 (CRC, 2013). CRC owns and operates the town water supply systems in the urban parts of its area. Raw water is extracted from 15 locations and is stored in 76 reservoirs after treatment. The main population area – Cairns city and suburbs – is supplied from Copperlode Falls Dam and Behana Creek (CRC, n.d.).
Copperlode Dam has a capacity of 37GL and a maximum extraction flow of 123ML/day. Water extraction is entirely gravity fed (Reimann, D., pers. comm., July 23, 2013). The water from Copperlode Dam and Behana Creek is treated at CRC’s Tunnel Hill water treatment plant (CRC, n.d.). After treatment and supply to the reticulation system, water samples from a number of points is tested for quality once a week by CRC’s Water Testing Laboratory (Wuth, M., pers. comm, July 23 2013).