Geelong Modelling program and future upgrades

1. Geelong Modelling programand future upgrades Mircea Stancu 25 June 2010

2. Barwon Water Regional Water Corporation South west of Melbourne

3. Geelong District Sewer catchment Geelong

4. Geelong District Sewer catchment

5. Geelong District Sewer catchment

6. Geelong District Sewer catchment

7. Population growth prediction GREATER GEELONG AREA 2045 PREDICTION New residents: between 88,000 and 142,000 Total ADWFs will increase by between 75ML/day and 100ML/day (over 50% increase) Increase in ADWF to Black Rock WRP between 69ML/day and 92ML/day (over 50% increase)

8. Geelong District Sewer catchment

9. Geelong trunk network • Trunk network in Geelong • Relatively isolated from northern flows • Relying on two main sewers • Very difficult to upgrade (going through Geelong CBD • High impact in case of failure • Future servicing strategy relying on smart use of interconnections and current capacity. Flow Retarding Facility New WRP

10. Geelong trunk network How it works

11. Current practice • Current Status Quo • Extensive use of WSAA code recommendations for smaller divisions • A current MIKE11/MOUSE trunk sewer model mainly used by consultants • No in-house expertise on model/software package

12. Monitoring program • Location of monitors • Monitoring for: • Level • Flow • EC • Rainfall • Monitoring Program: • Early phase of implementation • May be enhanced by temporary monitoring • 3 years long • Main scope is to provide reliable data for the modelling project

13. Modelling program scope • Will attempt to solve main issues we are facing such as: • How much spare capacity we still have in the pipes • How the interconnections will work and how the network will respond • How the new WRP to the north of Geelong will influence the network behavior • When we will need to upgrade the transport pipe from Geelong to Black Rock • MAIN SCOPE • Prove 1 in 5 years compliance • Providing better network behavior understanding • Providing critical information for new Capital Works Expenditure • Providing option analysis tools (best value for money) • Providing information for maintenance purposes (high infiltration areas, diversion flows, etc.) • ADDITIONAL SCOPE • Confirmation of sewer return ratios • Information regarding effects of water restriction on sewer flows • Confirmation of impact of repairs (e.g. sewer re-lining, de-silting) and replacements • Better prediction of the impact of new developments • Flow profiles and their impact on sewer mining options • Impact of sewer mining on network • Infiltration level information (including saltwater infiltration) • Horizontal integration with BW’s GIS system

14. Modelling resourcing and delivery options • Current ideas: • DEVELOPMENT: • Externally developed, internally maintained • Provides best combination of risk mitigation and value for expenditure • MODEL TYPE: • Detailed network • Longer setup time of geographical network however far easier to set up parameters and loadings • Corrected GIS data can be fed back into the GIS system • Less error prone to options analysis and inclusion of new developments and demands (no bulk catchments) • Provide a good platform for the modelling of other smaller areas for various purposes (infiltration modelling, sewer mining, flows diversions etc.) • Easy to improve in the future

15. Modelling resourcing and delivery options SUMMARY: My recommendation is for the model to be: - Detailed network - Externally generated - Internally maintained

16. Modelling project Implementation steps • Ensure stakeholders agreement and corporate support: Aug-Sept • Ask for capabilities statement and/or presentations from major software developers (i.e. write software requirements brief): Sept-Oct • Choose software package: Oct-Nov • Write consultants brief: Nov • Tender process: Nov-Dec • Project delivery: Early 2011 with yearly calibrations • Maintenance and training: 2011 onwards

17. Modelling project Implementation steps Discussion

18. Main outfall sewer DUPLICATION Main Outfall Sewer as a part of the overall network: MAIN OUTFALL SEWER DUPLICATION

19. Geelong District Sewer catchment

20. Main outfall sewer • Characteristics: • 10.5 km long • 1650mm dia • Strategic asset • Very shallow slope (1 in 3000) • Over 30 years old but in acceptable condition

21. Main outfall sewer and its duplication • MAIN OUTFALL SEWER • Close to reaching capacity in wet weather • We know it will need to be upgraded • The modelling program will provide better estimates of future flows and upgrade timelines • Running through major future development hence route needs to be decided before development occurs • Current capacity: 2000L/s • Predicted needed capacity (PWWF): 3600L/s • Will continue to transport all DWFs Development Boundary

22. Augmentation options • Same route has been decided • Three options: • Identical duplication (1650dia @ 1 in 3000 grade). Price: ~80 mil. • Rising main (1100mm dia). Price: ~40 mil. • Pressure gravity sewer (1100mm dia @ 1 in 3000). Can be pressurized. Price: ~60mil. Development Boundary

23. Difference in pumped flow volumes Option 2: Rising main Option 3: Pressure Gravity Sewer

24. Winning option • Questions? NUMBER 3: Pressure gravity sewer It provides significant advantages and very high flexibility, for a smaller price compared to an exact duplication.