1. Lower Lakes and Murray River Modelling (Virtual Weir Presentation / Discussion) Canberra 11 February 2009

2. To be Discussed Existing Modelling: RMA (2D) and ELCOM (3D) Modelling of Virtual and Partial Weir Simulations Model Setup Model Validation Model Results & Animations Model Uncertainty Empirical Calculations: Destratification / Richardson Number Calculations Seiche Volumes

3. Model Setup/Extents RMA 2D (Blue) : All areas upstream of Tidal Barrages & Downstream of Lock 1, Lake Albert disconnected ELCOM 3D (Green) : From Pomanda Island (upstream of weir location) to Murray Bridge RMA simulation executed first, then results fed to ELCOM (U/S & D/S Boundaries)

4. Model Validation Validation period 1/1/2008 – 14/7/2008 Objectives: Best match observed hydrodynamics (WL) and salinity Ensure key processes appropriately represented Understanding of model uncertainty Key Uncertainties Additional salt load along length of River Additional irrigation demands / groundwater losses?

5. Predicted Water Levels – Poltalloch Plains

6. Predicted River Salinity – Woods Point

7. Predicted Lake Salinity – Spatial Validation

9. Predicted 3D River Salinity – Wellington

10. Predicted 3D River Temperature – Wellington

11. Comparison Measured vs Modelled River Salinity

12. 2 yr “Prognostic Simulations” Examining what may happen in the future, given continuing high net evaporation (1982) levels, and variations in the South Australia’s border allocation (Border Allocations of 696, 796 and 896 GL/yr), through to the end of 2010. Simulations aimed at maintaining Lake Level at -1.3mAHD. Salt water introduced through Goolwa Barrage in October 2009. Stop logs positioned by-monthly based on water level balance calculation.

13. Predicted Water Levels – Lake Alexandrina

14. Timeseries Locations – Lake Alexandrina

15. Predicted Lake (2D) Salinities – Point 1

16. Predicted Lake (2D) Salinities – Point 5

17. Predicted Lake (2D) Salinities – Point 6

18. Predicted River (3D) Salinities – Wellington

19. Predicted River (3D) Salinities – Tailem Bend

20. Predicted River (3D) Salinities – Swanport

21. Animation: Lower Lakes 696 GL/yr

23. Animation: River (696 GL/yr)

25. Animation: River (796 GL/yr)

27. Animation: River (896 GL/yr)

29. Comparison at End 2010 696 GL/yr 796 GL/yr 896 GL/yr

30. Uncertainty Model can still be improved Validation only currently till Mid July 2008 (no destratification period) No validation data for low level and high salt available Uses 1 year (2007) wind (cannot predict future wind conditions) Wind spatially homogenous

31. Partial Closure Weir Simulations No Weir 1100m Gap 700m Gap 300m Gap 100m Gap

32. Simulated Water Level in Lake Alexandrina

33. Simulated Salinity (ppt) Wellington Bed

34. Pomanda Embayment Bathymetry River Channel Pomanda Island Lake Alexandrina N

35. Other Info