Truckee River Modeling System RiverWare User Group Meeting March 1, 2005

1. Truckee River Modeling System RiverWare User Group Meeting March 1, 2005 Tom Scott, Jeff Rieker and Shane Coors

2. Pyramid Lake Paiute Indian Reservation PYRAMID LAKE CALIFORNIA NEVADA Stillwater NWR Derby Dam Reno/Sparks TRUCKEE CANAL Fallon STAMPEDE Newlands Project TRUCKEE RIVER INDEPENDENCE BOCA LAHONTAN PROSSER MARTIS DONNER Carson City CARSON RIVER Tahoe City LAKE TAHOE

3. Pre-Newlands Project Lake Level 80 Feet Many Conflicting Interests… Pyramid Lake

4. Operations • Current Operations – 1935 Truckee River Agreement • 1944 Orr Ditch Decree • 1959 Tahoe Prosser Exchange Agreement • 1994 Interim Storage Agreement • 1997 OCAP • Future Operations – Truckee River Operating Agreement (TROA)

5. Model Objectives • Efficient management of an increasingly valuable natural resource – the Truckee River • Track the physical water daily • Track status of accounts in the system daily • Operate according to governing Policy • Forecast and plan for the coming year and years • Provide regular operational forecasts to stakeholders • Administer TROA

6. Truckee RiverWare Modeling System

7. Truckee Modeling System Concept • Takes historic, current, and forecast hydrologic data and simulates system operation, while continuously tracking the status of accounts within the Truckee/Carson river system. • Examine the analogous processes of managing a small company’s finances, and modeling the Truckee River Basin with RiverWare

8. Accounts Structure“Management Framework” Financial Management • Accounts provide the structure for managing finances within a company • All $ entering, passing through, and exiting the company are assigned to an account. • Accounts represent possible categories of income and expenses (i.e. sales, payroll, taxes, etc.) RiverWare • In RW, accounts provide the framework to manage Truckee River water according to basin policy • All water entering, flowing through, and leaving the basin is assigned to an account • Accounts include water owners and designated usages (ie. TMWA, Floriston Rate, Endangered Species, etc.)

9. Truckee Accounts Map

10. Accounting“Establish Current Status”

11. Accounting ModelStep 1: “Establish Current Status” Financial Management • Detailed, balanced accounting of all income and expenses from the beginning of the year to the current time • Generate the current status of all accounts in the budget RiverWare • Updates the status of all of the accounts on the system to the current time • References gage flows, reservoir storage volumes, and water usages within the system

12. Accounting Model Summary • Input is all current streamgage and reservoir storage data in the basin from DIADvisor • Computes accounts status after yesterday’s inflows, outflows, exchanges, and transfers • Output is hydrologic and up-to-date accounting data

13. Forecasting“Project Inflows and Depletions”

14. Forecast ModelStep 2: “Project Inflows and Depletions” Financial Management • Income and expenses must be forecast from current time to the end of the year • Forecast based on previous years’ incomes and expenses as well as current financial conditions RiverWare • Inflows to all reservoirs and all sidewater forecasted to the end of the year • Demands and diversions forecasted to the end of the year • Forecasts are based on analysis of historic values and current hydrologic conditions within the basin

15. Forecasting Model NRCS Forecasted April-July Volume Truckee River at Farad Volume: TOTAL sum 1000’s Acre-feet Flow: Daily RATE Volume per time

16. Forecast Model Summary • Input is NRCS volume forecasts at Farad and Fort Churchill gages. • Forecasts all inflows and depletions in the basin by a similar years analysis • Output is forecasted basin hydrology for the remainder of the year.

17. Alternative Forecast Input MMS ESP Tool

18. Additional Forecast Input Short-term Realtime Forecast

19. Operations “Simulate Remainder of Year”

20. Operations ModelStep 3: “Simulate Remainder of Year” Financial Management • Take current status of accounts, forecasted income, expenses and operational constraints and simulate flow of $ to end of year • Generate periodic (daily/monthly) status of accounts – Profit and Loss Statement RiverWare • Given current status of accounts, forecasted inflows, and depletions, simulate operations of the system from current time to end of year. • Generates the status of all accounts and physical quantities (flows, storages, etc.) each day throughout the simulation period

21. Operations Model“A flavor of Ops” • The heart of the Operations Model….. The Ruleset Defines basin policy and physical constraints in order to simulate operations to the end of the year

22. Operations Model“A flavor of Ops” Example Rules:

23. Operations Model“A flavor of Ops” Operational Criteria on Lake Tahoe • Water Surface elevation must not exceed 6229.1 ft • Operational Maximum release of 300 cfs • Absolute Maximum release of 2600 cfs • Minimum release of 50 cfs in the winter • Minimum release of 70 cfs in the summer • Outflow approaches zero when elevation nears rim according to a rating curve • Must release in conjunction with Boca Reservoir to satisfy the Floriston Rate • During April – October if Tahoe elevation is above 6225.5, • minimize Tahoe releases • During April – October if Tahoe elevation is below 6225.5, • maximize Tahoe releases • During the Spring when reservoir is near capacity, releases must be made • such that reservoir fills to 6229.1 ft but no higher. • If Tahoe is releasing minimum and the flows are not needed to • maintain the floriston rate, then an equivalent amount of water is stored • in Prosser Reservoir as “Tahoe-Prosser Exchange”

24. Operations ModelSample Output Lahontan Reservoir Storage Boca Reservoir Storage Farad Gauge Flow

25. Data Flow

26. DIADvisor DIADvisor host computer

27. Data Flow Between Models Reno Carson City

28. Automation • Data transferred to database at 2:30 PM each day • Accounting model run at 3:30 each day • Data retrieved from Reno in evening, forecast and ops model run when data arrives • New forecast available first thing in the morning

29. Water Quality Modeling • Utilize existing basin-specific water quality models • Eventually provide real-time decisions • Operate interactively with RiverWare • Data output from RW to external model • Model returns info to RW • Provides mechanism to link other models (groundwater, sediment, etc.)

30. WQ Modeling

31. Exchanged from Lake Tahoe Other Credit Water Acquired diversion rights Water Quality Water/Fernley M&I Water California M&I Water Fish Credit Non-Firm M&I Credit Storable Little Truckee River Single purpose power component of Floriston Rates Fish Water Private Water & Former Agricultural Water Rights Firm M&I Credit M&I Emergency Drought Supply What is Next? TROA • Proliferation of accounts: 7  20 • Each Reservoir goes from single purpose to multi-purpose. Any kind of water in any reservoir • Extensive exchanges and transfers throughout basin • “Operation by Committee” – Model must facilitate interaction by stakeholders.

32. The End Pyramid Lake