1. A Comparison of CalSimII and CalSim3: Parallel Application of Two Planning Models
James Gilbert, PhD
Nancy Parker
US Bureau of Reclamation, Technical Service Center

2. Outline Motivation Model setup and assumptions Comparing CSII and CS3
CSII and CS3 differencese
What’s in COS? What’s in PA?
Comparing CSII and CS3
Comparing scenario effects (PA-COS for each CSII and CS3)
What does CS3 tell us that CSII can’t?

3. Motivation:
Transition toward CalSim3 as primary planning tool for CVP and SWP
Identify issues or refinements through comparisons
In other words – start using CalSim3
What does a recent CalSimII analysis look like in CalSim3?
Test case: implement RoC on LTO scenarios
(we present a ‘proof of concept’ comparison of parallel CalSimII-CalSim3 studies – using recent RoC on LTO ‘Current Operations Study’ and ‘Proposed Action’ versions as the basis)

4. CalSim Background
Long-term water resources planning models for CVP-SWP systems
Assume a constant ‘level of development’ combined with historic hydrology pattern
Monthly time step with layered (‘cycles’) rules within time steps
System represented via LP formulation (constraints, weights, etc)
CalSim3 (CS3) refines spatial resolution and hydrologic representation

5. CalSim3 network & domain
Water Budget Areas and Demand Units
Channel and conveyance network
C2VSim Groundwater model
CalSim3 network & domain

6. RoC on LTO Scenarios “Reinitiation of Consultation on Long-Term Operations”
Current Operations Study (COS)
Demonstrates applicable criteria for CVP/SWP operations today
Includes D1641 and 2008 USFWS and 2009 NMFS Biological Opinion RPA’s
December 12, 2018 COA decision
Updates to CVP allocation and San Luis operation logic
Proposed Action Study (PA)
Increase operational flexibility through non-operational measures where possible to avoid adverse effects

7. Major Model Assumption Differences
Current Operation (COS)
Proposed Action (PA)
Sacramento River measures to reduce Fall-Run redd dewatering - shift in agricultural diversion timing
2006 American River Flow Management Standard
2017 American River Flow Management Standard (** not implemented in CalSim3)
OMR requirements based on USFWS RPA Actions 1-3 and NMFS RPA Action IV.2.3
Risk-based OMR management incorporating real-time monitoring and models where possible
Fall X2 standards based on USFWS RPA Action 4
Suisun Marsh Salinity Control Gate Operation for 60 days between June and September of above normal and below normal year types
Exports limited by Vernalis I:E per NMFS RPA IV.2.1
Risk-based management incorporating real-time monitoring
HORB installed between September 15 and November 30 of most years when flows at Vernalis is <5,000 cfs; occasionally also between April 15 and May 30 if Delta Smelt entrainment is not a concern
No HORB installed
Stanislaus River Appendix 2-E flows from NMFS RPA III.1.3
Stepped release plan for Stanislaus River flows

8. Implementation
CalSimII studies were prepared as part of Reclamation’s consultation with Federal fisheries agencies (January 2019)
CalSim3 updated based on review and revisions from DWR, Stantec
Code for COS and PA studies mapped to CalSim3
Variable names changed where necessary
CalSimII studies set up with historical hydrology (Q0) for consistency with CalSim3

9. Two ways of comparing:
Direct comparisons – do CalSimII and CalSim3 represent each study consistently?
Compare COS to COS, PA to PA
Effects comparisons – do CalSimII and CalSim3 represent the effects of the actions the same way?
Tabulate the difference between PA and COS for each CalSimII and CalSim3 – how do these differences compare?

10. CalSimII – CalSim3 Comparisons
Operations logic mapped between CSII and CS3
Additional upstream operations in CS3
Hydrology is different
Spatial refinement
Land-use based demands
Valley floor water budgets more complex
Delta demands and salinity ANN
Closure terms
Expect direct mapping of CalSimII logic to CalSim3 to give the same results?

11. Flow Comparisons

12. Sacramento River at Hood – version comparison: Differences difficult to discern at monthly scale

13. Sacramento R at Hood – version comparison: Annual comparison shows ~330 TAF more flow in CS3 compared to CSII

14. Sacramento R at Hood – version comparison: CS3 monthly average flows higher in Oct, March, May, Aug

15. San Joaquin R at Vernalis – version comparison: High flows are lower in CS3

16. San Joaquin R at Vernalis – version comparison: Monthly average pattern: CS3 most different in October - April

17. Delta Outflow – version comparison: Differences dominated by Sacramento and Eastside inflows

18. Delta Outflow: CSII – CS3 differences are dominated by increased Sacramento and Eastside inflows in CS3

19. Delta Outflow – version comparison: Differences dominated by Sacramento and Eastside inflows

20. Delivery Comparisons

21. CVP SOD Ag Delivery – version comparison: Different demands -> different deliveries

22. CVP SOD Ag Delivery – version comparison: Demand pattern differences throughout year

23. CVP SOD Ag Delivery – scenario comparison: Benefits to delivery in both CSII and CS3

24. CVP SOD Ag Delivery – scenario comparison: Timing of increased PA delivery not the same in CS3

25. Storage Comparisons

26. Folsom – version comparison: Greater dry year drawdowns in CalSim3; Higher storage in average years

27. Folsom – version comparison: CalSim3 storage higher in summer and fall

28. Folsom – scenario comparison: CSII PA has greater storage increase compared to CS3

29. Groundwater Comparisons

30. Groundwater representation is simplified (or absent) in CalSimII
CalSim3 coupled with C2VSim finite element mesh, stream reaches, and pumping/recharge
Groundwater pumping in CS3 has consequences
Explicit spatial representation of drawdown
Stream-groundwater interactions along main waterways

31. SOD Groundwater Pumping – scenario comparison Delivery increases reduce pumping

32. SOD Stream-Groundwater– scenario comparison Combination of reduced pumping and different channel flows yields mix of groundwater exchange effects

33. Stream-Groundwater Interactions: Modified Stanislaus flows affect groundwater exchange

34. Summary Scenario analysis is feasibly implemented in CalSim3
Differences in CalSim3 analysis result from increased resolution, refined hydrology
Simple mapping of CalSimII code to CalSim3 not sufficient – will need scenario-specific adaptation
The way to make CalSim3 a comparable tool – start using and testing it!

35. Looking ahead…
CalSim3 expands scope of what can be included in scenario analysis
For example: land fallowing impacts to consumptive use and delivery; groundwater as an additional ‘reservoir’
Ongoing refinements:
Water quality (salinity) in San Joaquin
Allocation and other system logic testing
Tulare expansion (Lauren Thatch’s presentation – next)
The way to make CalSim3 a comparable tool – start using and testing it!

36. James Gilbert USBR – Technical Service Center jmgilbert@usbr.gov
Thanks!