Water Journal : Water Journal April 2012
catchment management 100 APRIL 2012 water technical features Abstract Seqwater is responsible for supplying bulk-treated water to the South-East Queensland region. Seqwater recognises the importance of a whole-of-catchment approach, including natural and built assets, from catchment to supply. From a catchment management perspective, this process is informed by innovative and emerging techniques to establish and identify risks, assess how the risks can be effectively managed, and report on the risks and proposed mitigation at multiple spatial and temporal scales. Seqwater is also developing a suite of tools to measure the efficiency of investment in the catchment and the built infrastructure to effectively manage these risks. This results in a cost-efficient, integrated and strategic approach to managing our water resources. Introduction In July 2008, Seqwater was formed as part of Queensland Government reforms designed to deliver long-term security of water supplies. Seqwater provides bulk water storage and treatment services to the South-East Queensland (SEQ) Water Grid, which services approximately 2.5 million people. Seqwater has the responsibility for managing 25 dams, 47 weirs and 14 bore fields across South- East Queensland, which supply 46 water treatment plants. As a result we have a high diversity in source water catchments and water treatment capabilities, presenting many challenges for the production of safe drinking water. Seqwater has developed a Drinking Water Quality Management Plan, which adopts the framework under the Australian Drinking Water Guidelines (NHMRC/NRMMC 2004) and follows the approach of preventative management from catchment to supply. The challenge for the organisation lies in implementing and influencing change in the catchments to protect drinking water supplies, given our lack of catchment ownership or regulatory powers. The catchments feeding Seqwater's water supplies span approximately 1.4 million ha, of which Seqwater owns very little (< 5%), mostly land either underwater or directly adjacent to it. Human activity in the time since European settlement has left a significant environmental footprint on the watersheds. Only about one- quarter of the original vegetation in the region remains intact, much less occurring along rivers and streams in some catchments. The hydrology of watersheds has been substantially altered through the construction of dams and weirs, but also because of changes in land use and vegetation coverage. Land use across catchments and the proportion of protected area are also highly variable; however, the majority of water supplied by Seqwater is from open catchments. That is, the majority of the area is open to public access with a variety of urban, peri-urban, recreational and agricultural pursuits being undertaken. This is in clear contrast to other major water supply areas in Australia where the majority of the catchments are owned, naturally vegetated and closed to public and economic access. The profile of land use activities within the water supply catchments of South- East Queensland is closely linked to compromised water quality in lakes, elevated levels of risk to end users and greater water treatment costs. This paper aims to explore the integrated approach used to investigate links between water quality and catchment condition, and the steps being taken to address and improve catchment condition in Seqwater's catchments. Tools to Inform Management Seqwater is engaged in a number of monitoring and research activities that directly inform catchment management processes. Information from these programs feeds directly into our qualitative risk assessments, which identify risks within the catchment requiring attention. This is underpinned by a developing sanitary survey plan across the region to better inform risk assessment and analysis. Complementing the sanitary survey process, Seqwater is also engaged in developing tools for microbial source tracking with our research partners. This project is in development; however, preliminary work can demonstrate the value of this tool for informing risk assessment and catchment management. Initial work has focused around the use of a particular gene (gusA) of Escherichia coli that demonstrates significant variation within the gene, depending on whether it had an animal or human origin (Ram et al., 2004). This application is demonstrated in Figure 1, where analysis of the gusA gene for E. coli collected in two representative catchments shows that E. coli in these catchments is predominantly from an animal source. This finding can then provide information for catchment management and the setting of remediation targets in these areas to focus around animal-related activities (e.g. improved grazing/dairy management such as restriction of direct access to streams for animals, and reduction of feral pests). The biggest limitation of this source tracking method is that it relies on building a comparative database (library) A Watkinson, A Volders, K Smolders, A Simms, J Olley, M Burford, H Stratton, B Gibbes, A Grinham Novel techniques to assess the effectiveness of management intervention and prioritise action SOURCE WATER PROTECTION FOR SEQWATER Figure 1. Microbial source tracking in two catchments.
Water Journal May 2012
Water Journal December 2011