Water Journal : Water Journal August 2012
groundwater management refereed paper 88 AUGUST 2012 water technical features Introduction The City of Maryborough is located in the Central Highlands Region of Victoria, approximately 60km northwest of Ballarat on the Pyrenees Highway, and 170km northwest of Melbourne. Gold was discovered approximately 4km north of Maryborough in the early 1850s and the town grew rapidly shortly afterwards. While the population expanded to more than 50,000 citizens during the gold mining boom, in more recent times this figure is closer to 10,000. Prolonged drought conditions experienced throughout Victoria, including six consecutive years of below-average rainfall, had severely stressed the reservoirs servicing the City of Maryborough supply system, both in terms of volumes of water available, and water quality. This water supply stress had far-reaching impacts to the community in terms of severe water restrictions, but also to the responsible urban water supply authority, Central Highlands Water, with a mandated responsibility for ensuring continued potable water supply to the community. As a result, Central Highlands Water proactively sought alternate water supplies to augment the Maryborough supply system. Groundwater was identified as a practicable option and GHD was commissioned to provide hydrogeological support and engineering services to Central Highlands Water. Investigations were focused on developing groundwater contained in two 'Deep Leads' at Evansford and Moolort. This article presents an overview of the investigations undertaken by GHD for Central Highlands Water, with greater focus on the development of the Moolort borefield. Background The Maryborough and District water supply is the second largest system managed by Central Highlands Water and provides filtered water to Maryborough and several surrounding rural towns. A locality plan has been provided in Figure 1. The Maryborough water supply system contains three reservoirs that are managed by Central Highlands Water. The main water harvesting reservoirs are Evansford Reservoir (1,351ML capacity) and Talbot Reservoir (846ML capacity). Centenary Reservoir (180ML capacity), located on the southern outskirts of the city, does not receive natural inflow and serves as a central holding basin only. In addition, Central Highlands Water has a bulk entitlement to extract water from Tullaroop Reservoir (see Figure 1) each year (1200ML/year, with a minimum of 600ML/ year, and the capacity to carry over up to 900ML). Historically, the main sources of supply were Evansford Reservoir and Talbot Reservoir due to their superior water quality and reliable inflows. In recent years, however, changes in climate (drought) have affected the system performance and resulted in fundamental changes to the management of the system. Evansford and Talbot Reservoirs could not provide full supply due to insufficient inflow and there was a greater reliance on sourcing supply from Tullaroop Reservoir. However, the water from Tullaroop Reservoir has different characteristics, most notably higher salinity. Another effect of reduced inflows into the system was the resultant low reservoir levels and higher temperatures, and greater likelihood of algal blooms. To improve the quality, Central Highlands Water upgraded treatment with the introduction of aerators, which helped prevent algal blooms in the reservoirs by introducing oxygen and facilitating mixing. Planning Central Highlands Water developed a Water Demand Supply Strategy in accordance with the Guidelines for the Development of a Water Supply Demand Strategy prepared by the Department of Sustainability and Environment (DSE), with the assistance of VicWater and its members. T Anderson, P Russell, B Cossens, D Stanley A consultant, resource manager and urban water supply authority's perspective FINDING, DEVELOPING AND SUSTAINABLY MANAGING POTABLE GROUNDWATER SUPPLIES IN VICTORIA'S CENTRAL HIGHLANDS REGION Moolort Production Bore 1 headworks. Figure 1. Maryborough and District site locality plan.
Water Journal September 2012-1
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