Water is precious, particularly in South Australia, the driest State in Australia, with over 80% of its land area receiving less than 250mm of rainfall per year. Security of water supply has always played a critical role in the economic and social development of South Australia, and will continue to do so while dependency on water from the River Murray is so high and there is competition over this from states and for different uses – municipal, irrigation, industry, and the environment. The drive towards sustainable development has evolved to attenuate overconsumption of the world’s natural resources of which water is a key element. Provision of reliable water supplies to regional South Australia has always presented challenges, given the vast distances involved and the limited number of natural water sources. Despite these, a majority of South Australians enjoy the benefit of a reliable and safe water supply, adequate waste disposal system, good community health and high standard of living. A challenge remains to determine the sustainability of current major water pipe transfer systems from remote resources to small communities. There may be scope for managing existing water supplies more effectively and further developing local water harvesting and reuse solutions to minimise the need for more significant infrastructure investment. This study investigates the challenges and opportunities for extending development of non-potable (secondary) water supply schemes in South Australian towns. These schemes will conserve the State’s freshwater resources. The primary focus of this study is harnessing stormwater runoff and treated effluent generated by normal township development to supplement higher quality public water for uses such as irrigation of public areas and sporting fields in country areas. Water harvesting and reuse is not likely to occur due to some technological breakthrough but through application of known technology and the adoption of water conscious ethics by society. However, it is a sensible reality for the South Australian climate, particularly when coupled with appropriate conservation and suitable landscaping practices. Thus, the major theme of this study is information sharing since if people are familiar with and understand the concepts then more communities may be encouraged to develop their resources. Water reuse has proven to be a beneficial strategy for addressing stormwater runoff and wastewater disposal problems and alleviating localised water supply problems for several South Australian towns and communities. The existing projects demonstrate both the strong community-based and innovative approach to water resources management in this state. They are inherently simple in form, and can often be assembled with readily available materials by people with a basic understanding of plumbing and construction skills (locally available). The potential for localised water harvesting and reuse in South Australian towns is generally limited to single purpose communal non-potable systems. Further, it is likely to only be sustainable in rural communities willing to make a commitment to its long term, proper operation and maintenance, or they could endanger public health. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1283773 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil and Environmental Engineering, 2007

[Truncated abstract] Managed Aquifer Recharge (MAR) is a technique that can be used to capture and store water in aquifers for later reuse. This method recycles water that would normally be lost or discarded to the environment. MAR has been observed to have the potential for improving the quality of recharged water through a combination of physical, chemical and biological processes. The aim of this study was to investigate the changes in groundwater microbial population structure during MAR and the major influences that drive these population changes. Biogeochemical MAR studies have the potential to assist in the improved prediction of the removal of contaminants such as nutrients, pathogens and trace organics from the recharged water. Biological clogging during recharge also has the potential to overwhelm an aquifers ability to process wastewater thus reducing the hydraulic conductivity of the aquifer. Therefore further research into the spatial and temporal biogeochemical processes that occur during MAR is required. The geochemical and microbial population dynamics of two contrasting MAR techniques were investigated at two different geographical locations (Perth, Western Australia and Adelaide, South Australia). These MAR sites contained aquifers of dissimilar properties that were recharged with wastewater that contrasted in water quality. The Perth MAR site received secondary treated effluent which continuously infiltrated the unsaturated zone into an unconfined aquifer aided by infiltration galleries. Reclaimed water was extracted from a well at distance from the infiltration gallery. ... Notably the background and recovered water was most dissimilar in microbial and chemical population structure to that described for the infiltration gallery and injection well. Microbial and chemical evidence suggested that the background and extraction well groundwater were unaffected by plume migration. These results suggested that extraction well groundwater was similar in quality to that of ambient groundwater. Significant geochemical and microbial changes of secondary treated effluent during infiltration and lateral movement through aquifer were implicated in addition to the forced hydraulic gradient created from extracting fives time the volume of infiltrating wastewater. This study demonstrated that microbial populations and the geochemical processes associated with MAR can be studied and compared. Multivariate statistical methodology greatly simplified a vast array of dynamic biogeochemical information that could be dissected for meaningful interpretation over distance and time. The study evaluated the major biogeochemical influences which resulted in microbial and geochemical changes where it was noted that microbial populations were more dynamic than geochemical variation over time. Additionally biogeochemical comparative analysis indicated that microbial populations could change in population structure before a shift in aquifer geochemistry was detected. It is anticipated that the results from this study will benefit further research into the biogeochemical processes involved in water quality changes (e.g. nutrient removal, pathogen decay and biodegradation of trace organics) as well as controlling biological clogging of MAR schemes.