February 21, 2006

1. Oakdale Irrigation District Water Resources Plan A Community Plan. A Successful Future. Water Supply Reliability February 21, 2006

2. Public Involvement Technical Institutional Analyses Activities The Water Resources Plan Goals • Provide long-term protection to OID’s water rights. • Address federal, state, and local water challenges. • Rebuild/modernize an out-of-date • system to meet changing • customer needs. • Develop affordable ways • to finance improvements. • Involve the public in • the planning process.

3. Public Involvement Technical Institutional Analyses Activities The Project Team will need Board Input Throughout the PEIR Preparation • Numerous issues from Phase 1 need continued Board input. • Some items specifically relate to PEIR activities • Other items, while not strictly tied to PEIR, need continued Board discussion

4. Water Supply Reliability and prelude to Transfer/Annexation issues (Informational Presentation) Schedule of Board Involvement

5. What is Water Supply Reliability and Why is it Important? • “Reliability” can mean different things to different people, for example: • To all users of Stanislaus River Supplies • Reliability of Stan. River supply to OID • Reliability of OID supplies to an OID customer • Typically expressed as a % • Reliability drives OID’s ability to annex new lands and/or transfer water.

6. Oakdale ID Water Supply (2004 Usage) Stanislaus Pre-1914 Water – 257 TAF (93%) Stanislaus Post-1914 Water – 1.3 TAF (>1%) Groundwater – 4.4 TAF (2%) Drainwater Reuse 13.5 TAF (5%)

7. New Melones Reservoir constructed 1973 - 1983 1988 Agreement and Stipulation with Reclamation – OID and SSJID share the first 600 TAF of inflow If inflow < 600 TAF, Districts share curtailments based on a formula (600 – Inflow divided by 3) “Conserved water” up to 200 TAF but first spilled Stanislaus River Supplies to OID are Reliable – But not 100% Reliable

8. 3,000 2,500 2,000 F 1,500 TA 1,000 500 0 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 7 2 2 2 3 3 3 4 4 4 4 5 5 5 6 6 6 7 7 7 7 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 OID Stanislaus Water Availability New Melones Inflow Computer Models are Used to Simulate Operations and Runoff

9. 350 300 250 200 150 100 50 0 2 5 8 1 4 7 0 3 2 2 2 3 3 3 4 4 4 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 Oakdale ID Receives its Full Allocation in 61 out of 77 Years F TA 6 9 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 7 4 5 5 5 6 6 6 7 7 7 7 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

10. 350 300 250 200 150 100 50 0 2 5 8 1 4 7 0 3 2 2 2 3 3 3 4 4 4 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 1928 - 1934 246 – 300 TAF 1987 - 1992 230 – 300 TAF 1977 190 TAF F TA 6 9 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 7 4 5 5 5 6 6 6 7 7 7 7 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

11. Statistics Help Summarize Stan R. Reliability–Independent of Acres Irrigated

12. Overlaying Current Customer Demand Tells More of the Story 350 300 250 The expected range of OID 200 Stanislaus River demand not including current water transfer obligations is 262 to 299 TAF. 150 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

13. Without transfers, OID would need to augment Stanislaus River supply with additional sources under average ET conditions 9% of the time. Overlaying Current Customer Demand Tells More of the Story 350 300 250 The expected range of OID 200 Stanislaus River demand not including current water transfer obligations is 262 to 299 TAF. 150 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

14. Without transfers, OID would need to augment Stanislaus River supply with additional sources under average ET conditions 9% of the time. Overlaying Current Customer Demand Tells More of the Story 350 300 250 The expected range of OID Without transfers, OID would 200 Stanislaus River demand need to augment Stanislaus not including current water River supplies under maximum transfer obligations is 262 to ET conditions 21% of the time. 299 TAF. 150 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

15. Overlaying all Current OID Demand for Stan. R. Water Tells the Whole Story 350 300 The expected range of OID 250 Stanislaus River demand including minimum water transfer obligations is 292 200 to 329 TAF. TAF 150 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

16. Overlaying all Current OID Demand for Stan. R. Water Tells the Whole Story 350 300 The expected range of OID 250 Stanislaus River demand including minimum water transfer obligations is 292 With minimum transfer 200 to 329 TAF. obligations and average ET conditions, OID would need to augment Stanislaus supplies TAF 150 19% of the time. 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

17. Overlaying all Current OID Demand for Stan. R. Water Tells the Whole Story 350 300 The expected range of OID 250 Stanislaus River demand including minimum water transfer obligations is 292 With minimum transfer 200 to 329 TAF. obligations and average ET conditions, OID would need to augment Stanislaus supplies TAF 150 19% of the time. With minimum transfer obligations and 100 maximum ET conditions, OID would need to augment their Stanislaus River supplies with other sources in every year. 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

18. What if OID Annexed 5,000 Acres Today (under current policies)? 350 300 The expected range of OID 250 Stanislaus River demand including minimum water transfer obligations is 312 200 to 349 TAF. TAF 150 100 50 0 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

19. Conclusions (Current Land Use and Minimum Transfer Obligations) • In a maximum crop demand conditions, OID would need to augment its surface water supplies • Additional GW Pumping ($$ impact) • Reduced deliveries (modified rotations) • With average demand, OID would need to augment its surface water supplies 19% of the time

20. The Water Resources Plan Recommends Improving Current Level of Reliability • Developed conservative plan to meet worst case needs. • “Worst case” is defined as a maximum water demand condition occurring simultaneous to an extreme (5% chance of occurrence) Stanislaus River Curtailment • Strategy dependent on upcoming OID policy decisions regarding drought response, annexation, and water transfers

21. Implementing the WRP Improves Existing Customer Reliability Current Customer Reliability • From an in-District grower perspective, assuming the following: • Max ET (299 TAF) • 30 TAF minimum transfer obligation • No annexations • 15 TAF of emergency pumping capability • Reduced rotations resulting in 10-14TAF in delivery curtailments • Customer reliability is 79%

22. Implementing the WRP Improves Existing Customer Reliability Current Customer Reliability • From an in-District growers perspective, same assumptions, plus: • 5000 acres of annexations (current policies) • Maximum demand could be as high as 360 TAF (299+41+20). • With current facilities, this demand exceeds OID’s supplies

23. Implementing the WRP Improves Existing Customer Reliability Future Customer Reliability with WRP • From an in-District growers perspective, assuming the following: • 2025 Demands (233 – 265 TAF) • 50 TAF Minimum transfer obligation • Over 4,000 acres of annexations • 20 TAF of emergency pumping capability and increased drainwater reuse • Reduced rotations resulting in 10-14TAF in delivery curtailments • Customer reliability is 95 to 99%

24. OID Can’t Improve Stanislaus River Reliability, Just Customer Reliability • Customer Reliability is also affected by board policies, facilities (gw and reuse), and land use • The WRP is structured to be implemented over time • Reliability improves steadily over the course of implementation • Additional water transfers and annexations need to be carefully phased • Availability of water supply • Financing of the WRP

25. CEQA Scoping Meeting Schedule of Board Involvement

26. Expansion of Service Issues (Informational Presentation) and development of Annexation Policy Guiding Principles (Board Action) Schedule of Board Involvement

27. Water Resources Planning Committee Discussion of Annexation Policy Guiding Principles Schedule of Board Involvement

28. Annexation Policy Guiding Principles Board (Board Action) and Drought Response Plan (Informational Presentation) Schedule of Board Involvement

29. Water Transfer Discussion to include Extension of Existing Contracts, and Potential New Recipients. Confirmation of “Preferred Alternative”. Infrastructure Projects and Details (Informational Presentations) Schedule of Board Involvement

30. Protect OID’s water rights. Enhance customer service for all users. Rebuild, modernize, and expand system infrastructure. Protect the future water supply needs of the cities of Oakdale and Riverbank. Keep water rates affordable through a balanced effort of water transfers and service to “new” customers within OID’s Sphere of Influence. Substantially increase water supply reliability and meet OID service in a worst-case drought. Implementing Best Apparent Alternative Will Benefit OID’s Customers and the Community

31. Oakdale Irrigation District Water Resources Plan A Community Plan. A Successful Future. Water Supply Reliability February 21, 2006