During the latter part of last century, rising watertables across the Shepparton Irrigation Region (SIR) in Northern Victoria prompted significant public and private investment to manage and control salinity. This investment assumed shallow watertables, and associated salinity threats, would be a permanent feature of the SIR irrigated landscape. One of the many initiatives implemented to combat the salinity threat was the progressive installation of a Public Groundwater Pump network. The resulting network of 115 Goulburn-Murray Water (GMW) owned and operated groundwater pumps provided capacity for watertable protection to about 18,000 hectares of horticulture and pasture.
Since the onset of the Millennium Drought approximately 20 years ago, a combination of changes in climate, water use, irrigation practices, land-use and stakeholder expectations has led to a different understanding of the SIR salinity threat. This changed understanding has seen a shift from previously fixed and prescriptive groundwater and salinity management arrangements to adopting a more adaptive and flexible approach.
Design and Methodology
Consequently, a number of projects, such as rationalising the SIR observation bore network, have already been undertaken by GMW to ensure management of sub-surface drainage assets evolves to meet a more contemporary risk profile and is able to be adapted to foreseeable risk scenarios. GMW’s network of public pumps is now being rationalised to around 32 active pump sites. Watertable trends are monitored to ensure pumps can be readily reactivated if high watertables and salinity threats return. Ongoing salinity risk surveillance and reporting will continue, primarily through a web-based portal designed to better inform landholders about salinity threat changes.
Original data and results
The public pump rationalisation project, as with other recent initiatives, stems from a need to respond to significant climatic and landscape changes. Importantly, rationalisation of the public pump network is supported by sound science about changing watertable behaviour and salinity threats. The project is also responding to significant changes in irrigation and is strongly aligned with community expectations.
There is now a clearer understanding that long-term regional prosperity and resilience requires management responses that adapt to change and address uncertainty. The SIR Public Groundwater Pump Rationalisation project is clear example of recognising the value of important infrastructure and adapting its operation to changing circumstances.