2008•Proceedings of Water Down Under 2008Requires access
Development of a Catchment Water Quality Model for the South Australian Murray-Darling Basin
Luke M. Mosley, John E. Stewart, Benjamin Zammit, J Riggs
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Abstract
At present the lack of a catchment water quality model for the South Australian Murray-Darling Basin (SAMDB) makes the understanding and management of pollutant inputs difficult. The prolonged drought in the River Murray catchments is increasing pressures on the quantity and quality of water resources. Models are a valuable tool to predict water quality outcomes, particularly at the large catchment scale. A catchment water quality model has been built for the SAMDB region using the 'E2' modelling framework. Sub-catchments within the study area were delineated. The hydrological model was built and calibrated for the major tributaries entering into the River and Lakes (e.g. Marne, Angas, Bremer, Finniss rivers; Burra, Rocky Gully, Saunders, Preammima, Tookayerta, Currency creeks). The generation, transport, and possible retention/transformation of key pollutants (sediment, nutrients, salt, and bacteria) from diffuse and point source pollution from the sub-catchments was modelled. Farm dam storages were also accounted for in the model. The development of the model will allow the EPA and its stakeholders to achieve the following broad objectives: - Develop an increased understanding of the sub-catchment contribution to water quality in the streams, River Murray and Lower Lakes; - Predict current and future water quality as related to various conditions (e.g. catchment management, land use change, climate variability, pollutant input reduction); - Prioritise pollution and water quality management requirements, including potential legislative and non-legislative options to reduce pollutant loads; - Provide catchment pollutant load inputs to an in-stream River Murray hydrodynamic and water quality model, which is being developed concurrently; and - Assist with setting of regional specific water quality objectives and resource conditions targets in the Environment Protection (Water Quality) Policy and Regional Natural Resource Management respectively.