Understanding shallow groundwater use behaviour in the Shepparton Irrigation Region to inform water policy Irrigation Australia Limited Conference 2012 Samantha Longley, Helen Murdoch and Geoff Kaine

The Shepparton Irrigation Region The SIR is located in northern Victoria Around 45% of the area is irrigated Historically shallow groundwater was extracted by horticulturists for asset protection Demand increased for the resource Initiation of SIR LWSMP and GMP

Characteristics of shallow groundwater in the SIR Ancestry stream deposition Different gradients of gravels and sands Aquifer salinity levels differ across the region Each user experiences quantity and quality that is different to other users. Is responsive to climatic conditions therefore changes quantity and quality over time. Managed to 25m below the natural surface

August 1995 watertable levels

Management during wet conditions G-MW facilitated an incentive scheme Eligibility criteria was imposed –Water table levels –Minimum flow rate –Maximum salinity

August 2005 watertable levels

Dry conditions Reduction of watertable levels Improvements in future shallow groundwater management needed Additionally, climatic uncertainty, system modernisation and improved water use efficiency also drives the need to reassess management.

The challenge Protecting the value of shallow groundwater resources in drier periods while maintaining the capacity to deal with the salinity threat of high watertable levels during wetter periods.

Understanding shallow groundwater use behaviour - Social Research Objective: To better understand shallow groundwater users expectations, needs and behaviours Based on the notion that; Decisions about the use of shallow groundwater are highly involving for producers. This means they will follow a complex decision making process to turn the switch on. The outcomes of this decision is dependant on the perceptions of net benefits.

The research Interviewed 45 shallow groundwater users Semi structured interview –Groundwater use –Salinity management –Groundwater resource management

Results – Response Tree Yes Is it a reliable resource?No Yes 6 How is it used? Is it used for irrigated farm production? YesNo 5 How is it used? Is it used for irrigated farm production? No 7 How is it used? Does groundwater salinity affect usage? No Is it a reliable resource?No Yes 2 How is it used? Is it used for irrigated farm production? Yes 4 How is it used? Is it used for irrigated farm production? YesNo 3 How is it used? Opportunistically Regularly OpportunisticallyAsset protection S&D Not at all Asset protection S&D Not at all Asset protection S&D Not at all 1 How is it used? Asset protection S&D Not at all 8 How is it used? Opportunistically Regularly Shallow groundwater use in the Shepparton Irrigation Region

Segment 1 – unable to access Sub-segments “Stock & Domestic” and “Not at all Segment perceived good quality groundwater but unreliable, not used for irrigated farm production Main income not from farm, groundwater used infrequently Bores could come back into use if farm situation changed

Segment 4 – an asset Sub-segments “opportunistically” and “regularly” Segment perceived good quality groundwater & reliable resource, used for irrigated farm production Opportunistic use - changes in response to variation in seasonal production mix Regular use – priority on maintaining permanent pasture & greater allocation of groundwater compared to surface water

Segment 5 – sleepers Sub-segment “Not at all” Segment perceived salinity levels require management but not a reliable resource, not used for irrigated farm production Effectively “sleeper” licence holders – pumps not working, other pumps on farm Might decommission in future, particularly if licence costs increase

Segment 6 – limited by availability Segment perceived salinity levels require management but not a reliable resource, used for irrigated farm production When able to access, groundwater was pumped because it was needed for farm production Usage regulated by availability

Segment 7 – too saline Sub-segment “Asset protection” Segment perceived salinity levels require management & reliable resource, not used for irrigated farm production Groundwater too saline for productive use Groundwater pumped to protect an asset

Segment 8 – an asset requiring management Sub-segments “opportunistically” and “regularly” Segment perceived salinity levels require management & reliable resource, used for irrigated farm production Opportunistic use depended on weighing up costs & quality when deciding on groundwater use to meet changed production mix & quality issues Regular use – priority on maintaining permanent pasture production All used during drought – knew of salinity risk but talked about groundwater as “lifesaver”

Outcomes of research for consideration 1.Shallow groundwater in the SIR is an opportunistic resource 2.No concerns from existing users if additional entitlements are allocated 3.Less intensive management desired 4.Provide incentives in key areas

Options generated by G-MW 1.Cap, Trade and Allocation regime 2.Reclassify shallow groundwater 3.Unbundle shallow groundwater

Questions?