eWater CRC is working on local water management issues in partnership projects with organisations in South Australia, at their request.
Focusing on the Mount Lofty Ranges catchments, the project teams are applying water management software to model the relationship between land-use, climate, water-quality and flow, and the impacts these have on supporting viable fish populations.
In the process, eWater’s model developers are testing the capability of the software as they adapt it to match the needs of this catchment.
The Mount Lofty Ranges catchments cover over 4000 km2 and are home to 77% of South Australia’s population, with around 160 townships in the region.
This is also a highly productive agricultural area with fertile soils and reliable annual rainfall of up to 1600 mm.
The region is under pressure from human activity and extensive use and is facing a changing climate, landscape, and hydrological regime. It has five major rivers: Gawler, Torrens, Little Para, Sturt and onkaparinga. Only 13% of the original native vegetation remains, though there are many areas of high biodiversity significance.
The state’s natural-resource managers are juggling the environmental and human demands for water resources.
The long term health of the catchments is important not only for inhabitants and ongoing land-use activities, but also for Adelaide’s watersupply since the region’s eight large reservoirs supply 60% of Adelaide’s current demand, which is increasing.
In this eWater application, the project team is using our software to predict the movement of runoff, sediment and nutrients for a range of scenarios.
The project is also assessing likely ecological responses to flow patterns in regulated river reaches.
The outputs should have the potential to help direct management actions and water-release decisions.
Two of eWater's next-generation software tools were applied:
(i) exploring future water quality and yield possibilities, using eWater’s catchment modelling framework Water Cast; and
(ii) building ecological models of the water requirements of viable fish populations in the regulated parts of the Onkaparinga River. eWater partner organisations will combine these with the catchment-model outputs to explore ecological responses to scenarios of flow patterns.
The South Australian EPA has previously used modelling to explore catchment contributions to water quality in this region with existing land use.
With an earlier version of eWater’s software (‘E2’), they quantified the loads of key contaminants that could potentially run off sub-catchments and into creeks, found cause and effect relationships, and were able to prioritise what needed to be done to manage contaminants and water quality. This included potential legislative and on-legislative
The present application
Using data from local catchments and sub-catchments, the team this year is adapting eWater’s new catchment management software framework Water Cast to match the specific local conditions of rainfall, soil type and land use. The tool will be put through various scenarios to see how water yield and quality are likely to vary in response to changing conditions, including different land uses and lower rainfall.
Meanwhile, local data on flow characteristics, water quality and fish species’ requirements are being entered into eWater’s ecological modelling software tool ‘Eco Modeller’.
This tool lets you call on accumulated scientific knowledge about freshwater fish and invertebrates and apply it to potential river scenarios; it will enable users to predict probable responses of the fish species in the Onkaparinga River as flow changes in its regulated reaches.
Once the models are specifically tailored to the Mount Lofty Ranges, they will be teamed together to make trial predictions of water quality, yield and fish responses to a range of scenarios of management and climate.
Click on the button below to download a copy of the Progress Report on the Mount Lofty Ranges Source Catchments Application Project. (720KB)
Click on the button below to download a copy of Analysis of Total Suspended Sediment and Total Nutrient Concentration data in the Mount Lofty Ranges to derive Event Mean Concentrations.
This application of eWater’s software gives our South Australian partners a potential way of investigating likely outcomes of their water management activities in this area.
Although the models are specific to this region, they are developed in such a way that the general approach and information requirements may be applied to similar situations elsewhere.
All eWater tools demonstrated in focus catchments are part of our integrated modelling suite.
South Australian Research and Development Institute (SARDI)
Department of Water, Land and Biodiversity Conservation
South Australian Water Corporation
SA Environment Protection Authority
Adelaide & Mt Lofty Ranges NRM Board