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Source Catchments: Realising whole-of-catchment water management

"Applying a whole-of-catchment approach to water management is now possible thanks to Source Catchments, the first component of eWater’s integrated water modelling suite, eWater Source, to be publicly released.

A water quality and quantity model, Source Catchments is designed to help natural resource managers and consultants develop targets, prioritise improvement programs and measure the effectiveness of a broad range of catchment management activities.

The landmark software provides a framework for modelling the amounts of water and contaminants flowing though a catchment and into major rivers, wetlands, lakes, or estuaries. Source Catchments integrates an array of models, data, and knowledge that can be used to simulate how climate and catchment variables (like rainfall, evaporation, land use, vegetation) affect runoff, sediment and contaminants.

eWater CRC CEO Professor Gary Jones said that Source Catchments demonstrates the extensive capabilities, flexibility and integration that will be a hallmark of eWater Source.

“Source Catchments is already proving its worth in addressing declining water quality in the catchments near the Great Barrier Reef. It is the first module released from our ground breaking eWater Source product that will be a significant step forward for Australian water managers.

“The fruit of collaboration between leading Australian scientists and industry partners, Source Catchments will be complemented by future module releases that include Source Urban for water management within cities, and Source Rivers, for large river systems.”

Science into action

Scientists at eWater have been working for a number of years on different facets of a software product able to assess streamflow in rivers, and the sediments and contaminants carried with it. The interactions are complex, so a single framework that brings this together makes the difficult job of catchment managers easier.

The software has been evolving and improving through extensive testing of earlier prototype and beta versions. The software expands on the flexible framework approach embodied in the E2 modelling framework. E2’s distinctive characteristic is that it does not contain fixed model structures or algorithms: instead a range of options are available to the user to ensure optimal alignment between the modelling objective and the attributes and details of the model.

Then as WaterCAST, the software was subject to considerable testing and user feedback to develop a new level of functionality in terms of sophisticated data pre-processors and analysis tools, additional component models and a modernisation of the user interface to facilitate scenario development and reporting.

Now, confident in its capabilities, eWater is launching the model as Source Catchments, the first building block of the integrated water management framework, eWater Source.

Answering catchment management questions

Source Catchments can predict the flow and constituent loads at any location in any catchment over time. It usually runs on daily time steps and produces reports at chosen spatial and temporal scales. Scenarios of interest can include actual or planned changes in land use, land management, or climate.

Source Catchments allows users to answer a range of management questions, such as where to place on-ground works to maximise water quality. It can also look at how climate change might affect the sediment balance in the catchment, or what might happen if plantation forestry replaces cropping in a certain subcatchment. Source Catchments modelling can be set up to handle bushfires, floods, droughts, and construction, all of which can adversely affect catchments.

For the last few years eWater and its partner organisations have been road-testing and refining the software in a number of key catchments around Australia. These catchments include four whose rivers feed into the sea adjoining the Great Barrier Reef (the Fitzroy, Pioneer, Burdekin and Barron). It includes catchments of the Hawkesbury–Nepean, the Yarra and Goulburn–Ovens rivers, and streams in the ACT and the Mt Lofty Ranges, South Australia. In all these areas, Source Catchments has shown its mettle, paving the way for the new release.

Queensland Murray–Darling Basin

The QMDC’s Chief Executive Officer, Geoff Penton said that Source Catchments provides the Queensland Murray-Darling Committee with an additional means of communicating to both government and landholders about the relative impact and effectiveness of investing in on-ground works of differing types and scales.

“Our region’s Natural Resource Management Plan identifies targets for no further increase of in-stream nutrient and sediment loads and an improvement in riverine and soil health,” Penton said.

“The Source Catchments modelling tool has allowed us to demonstrate the impact of actual and planned on-ground activities against those targets by showing condition and trend under different management strategies.”

Penton said that Source Catchments has provided a consistent mechanism for evaluating loads and concentrates of contaminants, under scenarios that include actual or planned changes in land use, land management, climate variability and climate change.

“By demonstrating the impact of management actions on water quality, the Source Catchments modelling resulted in QMDC achieving State and Commonwealth Government acceptance of the modelled data as a surrogate whilst waiting for longitudinal resource condition monitoring.”

QMDC also uses Source Catchments to support their communication activities with key stakeholders such as farmers and landcare groups.

“Source Catchments is an effective way to demonstrate that an improvement in land management practices such as reducing grazing pressure or fencing off riparian zones, will lead to tangible reductions in soil and nutrient loss,” said Penton.

“We can sit down with groups of farmers and give them a demonstration of the various impacts of onground works as well as identifying how much or how little they need to do across a subcatchment to make a sustainable difference.”

Investing in sustainable natural resource management in South Australia

The Adelaide and Mount Lofty Ranges region in South Australia covers the Barossa through to Victor Harbour and includes a mosaic of bushland remnants, farming land, and urban development.

The Environment Protection Authority (EPA) is South Australia’s leading environmental regulator and is responsible for the protection of water quality in the state. The EPA has been using Source Catchments with the Adelaide and Mount Lofty Natural Resource Management Board to target on-ground works, assess future land used changes and to look at a range of scenarios to inform the Water Quality Improvement Plan. A key feature will be the ability to assess the impact of runoff from farm dams in relation to water allocation planning.

Modelling Sediment in the Tamar

In 2006 NRM (Natural Resource Management in Tasmania) North secured $260,000 from the Australian Government to investigate the key processes, causes and fate of sediment transport in the Tamar Catchment contributing to the excessive sedimentation of the Tamar Estuary.

The project involved developing a WaterCAST sediment model (now known as Source Catchments) to quantify the amount of sediment entering the Tamar Estuary from the North and South Esk river systems and to identify the areas in the catchment the sediment came from.

Identifying the source of sediment enables the Tamar Estuary and Esk Rivers (TEER) Program and its partners to target on-ground works in the upper catchment area to minimise sediment and nutrient inputs into the river systems.

The results suggest between 58,000 and 80,000 tonnes of sediment is generated in the Tamar catchment area each year.

“The high slopes and rainfall zones of the upper South Esk and North Esk rivers appeared to be generating more sediment than the Macquarie, Lake and Brumbys River catchments.

“While urban and some agricultural land users are not discharging high overall loads due to the small catchment area they occupy, their load per unit area can be much higher than other land users,” NRM North Chief Executive Officer, James McKee said.

TEER Program Manager Amanda Locatelli said the project was one of a number of ongoing studies and initiatives of the TEER Program and its partners to investigate and address sedimentation of the Tamar estuary.

“Identifying the area in the catchment that sediments and nutrients are sourced from enables the TEER Program and its partners to target on-ground works in the upper catchment area,” Locatelli said.

“Our next step will be working with industry groups and landholders to provide incentives for planting riparian buffers and mitigating erosion in the catchment as well as targeting the delivery of Property Management Plans through NRM North to minimise sediment and nutrient inputs into the river systems.”

Try Source Catchments for yourself

While Source Catchments has been fully trialled in a range of application projects around Australia, nothing compares to seeing how it works in your own catchment. Visit our website to download a fully functional copy of Source Catchments, with the first 12 month license fee waived.


The final report is available to download from the NRM North website


On Source Catchments visit

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