Protecting the Investment in Modernised Irrigation:

1. Protecting the Investment in Modernised Irrigation: Adapting Successful Drainage Strategies to a Changing World in the Shepparton Irrigation Region Terry Hunter – Goulburn-Murray WaterDamien Finlayson – URS Josh Cimera – Goulburn-Murray Water

2. Water management 10+ years driven by resource scarcity • Previous focus on managing adverse impacts of irrigation • This presentation focuses on the re-emerging salinity threat in the Shepparton Irrigation Region

3. Presentation Outline • Shepparton Irrigation Region Context • Climate – Rainfall • Watertable Response • Future Salinity Risk • Adaptive Management

5. SIR Context • Covers ~500,000 ha • Major Victorian Foodbowl • Annual irrigation deliveries 1000 - 1500 GL

6. Historical Hydrological Data (1881-2011) Regional Rainfall Average annual ~ 460 mm Regional Potential Evaporation • Summer: average annual ~ 700mm • Autumn: average annual ~ 300mm • Winter: average annual ~ 150mm • Spring: average annual ~ 400mm • Total annual average ~ 1,550 mm

10. Note: Residual rainfall = cumulative deviation from the average

11. Note: Residual rainfall = cumulative deviation from the average

12. Note: Residual rainfall = cumulative deviation from the average

13. Note: Residual rainfall = cumulative deviation from the average

14. Note: Residual rainfall = cumulative deviation from the average

15. Note: Residual rainfall = cumulative deviation from the average

16. Messages From Historical Rainfall Data • There is no obvious pattern in the cycle of drought & wet periods across the SIR in: • duration • occurrence, or • intensity • The second half of the 20th century was wetter than the first – coinciding with rapid expansion of irrigation systems.

17. Rainfall and Groundwater Response

26. Watertable Response

27. SIR Salinity History – Environmental Impact

28. SIR Salinity History Economic Impacts by mid 1990’s • 270,000 ha with watertables less than 2 m below NS • 65,000 ha protected by groundwater pumps • In current $ terms with no pumping • Production losses due to salinisation estimated at ~$100 million/year • Regional losses estimated at ~$400 million/year

29. SIR Salinity History Management Responses

30. Regional Groundwater Response

31. Regional Groundwater Response

32. Future Salinity Risk • SIR salinity risk is driven by hydrologic loading • Not feasible to predict future salinity risk (when or where) • An “Adaptive Management Approach” is therefore needed to cost effectively mitigate the impact of salinisation • Economic risk of no action very high • Existing LWMPs are fundamentally sound • need to evolve to become adaptive

33. Future Adaptive Management Approach • Management based on recent data, recent bore trends, and historical data not “potential” future scenarios • Defined Salinity Management Phases: Monitoring/Planning/Works • Salinity management “zones” defined by groundwater level response • Integration of Adaptive Salinity and Resource management frameworks

34. Future Adaptive Management Approach

35. Future Adaptive Management Actions • All Conditions (Wet or Dry) • Monitoring • Analysis and Evaluation • Reporting • Planning (strategy development, program development, Research & Development) • Oversight, Co-ordination & Communication

36. Future Adaptive Management Actions • Wet Conditions (rising watertable) • Recommission private and public pumps • Promote private groundwater pumping • Install new pumps (private and public) • Adjust/refine irrigation water salinity guidelines • Dry Conditions (falling watertable) • Decommission/mothball private and public pumps • Adjust/refine irrigation water salinity guidelines

37. Key Issues • The recent drought reduced the short term impacts of salinisation • Recent rapid groundwater level recovery demonstrates that large areas of the SIR are still threatened by salinisation • Ongoing investment and management required to mitigate SIR salinity risk

38. Key Issues • Salinity management must be resilient and adaptable and have simple, robust rules • Need to balance “equity”, cost effectiveness and greater community good • Community understanding and “buy-in” is essential • Government investment likely to be event driven • Funding uncertainty

39. In Conclusion Adaptive salinity management is fundamental to sustainable irrigation in the Shepparton Irrigation Region

40. Partnership Acknowledgment This project is funded as part of the Goulburn Broken Catchment Management Authority Regional Catchment Strategy in the Shepparton Irrigation Region and is provided with support and funding from the Australian Government and Victorian Governments This project is delivered primarily through partnerships between the Department of Primary Industries, Goulburn-Murray Water, Department of Sustainability and Environment, Local Government, the Goulburn Broken Catchment Management Authority and other bodies.

41. Thank You Questions? Contact Details: Joshua Cimera Goulburn-Murray Water PO Box 165 Tatura VIC 3616 Phone: +61 3 5826 3895 Email: JoshuaC@g-mwater.com.au