Major Storages Water Quality Study
G-MW has important obligations and responsibilities with respect to management of potential threats to water quality and quantity. Concern exists that land management and development practices in water supply catchments is adversely impacting on storage water quality and quantity, and that the management of these activities needs to be improved. Issues of primary concern include nutrients and blue green algae, sediments and turbidity, salinity and pathogens.
In short, G-MW hopes that this project will develop our capability to better predict the impacts of land and storage management on the water quality in G-MW storages. Building upon recent water quality trend analysis, this project aims to further investigate these issues in depth by utilising predictive software water quality models for select G-MW storages and their catchments. In essence the project can be thought of as having three main components, a catchment modelling component and a storage modelling component and a communications component.
The catchment modelling involves construction of catchment surface water quality software models for two case study areas, the Upper-Mid Goulburn Catchment (includes Lake Eildon and Goulburn Weir) and the catchment to Tullaroop Reservoir in the Upper Loddon River catchment. Scientists working with the Cooperative Research Centre for Catchment Hydrology (CRCCH) have developed a catchment modelling 'toolkit' (http://www.toolkit.net.au/cgi-bin/WebObjects/toolkit). Models within the toolkit are capable of assessing hydrologic impacts of land use and water management decisions on whole of catchment scale. Models of sediments and nutrient fluxes have been built and are being used to identify and prioritise catchment areas for works and activities to improve water quality. The models can also be used to run predictive scenarios such as the effects of large scale land use change on water quality, for example. Ongoing model development by the CRCCH will see further improvements in modelling capability and accuracy in coming months.
The storage modelling work involves the construction of water quality software models for key major storages in the two case study areas, including Lake Eildon and Tullaroop Reservoir. State of the art storage hydrodynamic and ecological models are currently being constructed based on a modelling system developed by the Centre for Water research (CWR) at the University of Western Australia (http://www2.cwr.uwa.edu.au/~ttfadmin/). These models will provide us with a far better understanding of storage hydrodynamic and environmental processes. Model outputs will enable us to better understand the fate and transport of pollutants (e.g. blue-green algae, pathogens etc) within storages, and predict the likely effect of storage management and operational practices and policies. These models require high quality supporting data to calibrate and validate model predictions. We have recently installed a number of water quality data collection systems to assist this process (http://rtm.cwr.uwa.edu.au/olaris/index.php - select Lake Eildon and LDS data source). We are also outputs from the catchment models as input data to drive the storage models.
The other major task is the communication of modelling results. Using information gathered, we hope to work with other agencies, government and interested stakeholders to develop rigorous, scientifically based, plans, guidelines and protocols to better manage these threats. Models will be provided for use to other catchment managers and relevant stakeholders to help address questions of land and storage use and management impacts. Overviews of preliminary model outputs are summarised on attachments to this webpage, while more comprehensive model reports can be made available upon request.
This project is scheduled for completion by July 2005, though data collection and refinement is an ongoing process, and the models will continue to be supported and used in coming years. Depending upon the success of the project, it may also be further rolled out to incorporate modelling of other G-MW storages.
For further information contact:
Anne Graesser - Manager Water System Health
Phone: 5833 5786
Email: anneg@g-mwater.com.au
