Innovative solutions are required to meet the conflicting criteria of service level, community need, community desire, cost and risk to the supply authority in the delivery of water quality improvements to small regional communities. Grampians Region Water Authority services 74 towns in North-Western Victoria, an area of generally low rainfall, sparse settlement and few natural waterways. Town populations range from 10 to 13,000, with 56 towns having less than 500 people. A Water Quality Improvement Plan was recently developed by Grampians Water to address these natural difficulties. The plan examined a broad range of alternatives beyond the single-pipe reticulated supply system, including dual-pipe reticulation, rainwater sources and household water treatment systems for achieving target quality levels. The key findings were:
• regional treatment plants are not economical if towns are more than 25 km apart
• salinity is a major influence on strategy
• for low salinity supplies, conventional treatment is most economical
• for marginal salinity supplies, a two stage process involving conventional treatment and desalination is appropriate
• desalination provides a total solution for high salinity groundwater supplies
• drinking quality can only be economically achieved in very small towns by using household treatment of rainwater in a dual supply system. The resultant strategies and implementation issues outlined reveal some significant variations to the conventional approach.