1. Multipurpose Reservoirs and Reservoir Systems
David Rosenberg
CEE 6490 – Integrated River Basin / Watershed Planning & Management

2. Learning Objectives
Diagram multi-purpose operations for a single reservoir
Describe rules of thumb for drawdown and refill of reservoirs in series
Compare rules of thumb for reservoirs in series and in parallel
Illustrate use of rules in real reservoir systems
Integrate rules into reservoir simulation models
Mokelumne River
Calaveras River
Mokelumne and Calaveras Rivers, CA (Google Earth)
CEE 6490

3. Multi-purpose Reservoir Operations
Partition reservoir storage into “pools”
Each pool has a separate purpose
Release (or avoid releasing) water to reach the “guide curve”
Dead/Inactive pool (no release)
Buffer pool (min. in-stream flow releases)
Conservation pool (release to meet water supply / hydropower delivery targets)
Flood pool (release to empty, but don’t flood downstream areas)
Surcharge pool (emergency spillway releases)
Top of dam
Guide Curve
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4. Storage in thousand acre-feet
Seasonal guide-curve
1,000
900
800
700
600
500
400
300
250
Storage in thousand acre-feet
Contours are preceding 60-day basin-mean precip. (% of normal annual precip.)
Release all excess storage above line as rapidly as possible, subject to:
Do not exceed 50,000 cfs or maximum rate of inflow for flood event
Do not exceed 150,000 cfs at any time
Flows in a downstream damage reach do not exceed 180,000 cfs (HEC, 1976)
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5. Comparing Operations Objectives
Purpose
Single Reservoir
Reservoir System
Water Supply
Keep reservoir full; avoid spills; meet demands
Avoid system spills*
Flood Control
Keep reservoir empty; avoid damaging releases
Avoid damaging releases*
Energy Storage
Keep reservoir full + high head
Max. total energy stored at end of refill season*
Hydropower Production
Keep reservoir full; meet energy demands
Max. value of energy production*
Recreation - Pool
Keep reservoir full
Equalize marginal rec. benefits of additional water
*Releases to achieve objective depend on spatial configuration
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6. Rules of Thumb Rules differ for different Reservoirs Reservoirs
Water uses
Spatial configurations
inflow
release/spill
Reservoirs
in Series:
inflow
release/spill
Reservoirs
in Parallel:
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7. Operations Rules for Reservoirs in Series
Purpose
Refill Period
Drawdown Period
Water Supply
Fill upper reservoirs first
Empty lower reservoirs first
Flood Control
Energy Storage
Hydropower Production
Maximize storage in reservoirs with greatest energy production potential
Recreation
Equalize marginal recreational improvement of additional storage among reservoirs
CEE 6490

8. Operations Rules for Reservoirs in Parallel
Purpose
Refill Period
Drawdown Period
Water Supply
Equalize probability of seasonal spill among reservoirs
Equalize probability of emptying among reservoirs
Flood Control
Leave more storage space in reservoirs subject to flooding NA
Energy Storage
Equalize expected value (EV) of seasonal energy spill among reservoirs
For the last time-step, equalize EV of refill season energy spill among reservoirs
Hydropower Production
Maximize storage in reservoirs with greatest energy production potential
Recreation
Equalize marginal recreation improvement of additional storage among reservoirs

9. Illustrations and applications
Feather and Yuba Rivers, CA
(Rosenberg, 2003)

10. The Basins 2 parallel reservoirs
4.8 MAF storage (90% of mean annual flow)
Drains 4,100 mi2 within larger 27,000 mi2 of Sacramento River Basin
3rd Marysville reservoir authorized, but never built
Flood protection, Water supply, Hydropower, Recreation, In-stream flows

11. Feather and Yuba Rivers, CA Schematic
CEE 6490

12. Feather and Yuba Rivers, CA Analysis Method
Build Reservoir Simulation Models
HEC-ResSim for flood operations
Synthetic storms, various return periods, hourly time-step
HEC-5 for water supply, hydropower and in-stream flow requirements
Period-of-record of inflows, monthly time-step
Specify performance objectives (more next slide)
Simulate project alternatives
Base case (existing)
Storage reallocations (raise and lower guide curves)
Re-operate for lower downstream flood flow requirements
Select preferable alternative(s)
CEE 6490

13. Feather and Yuba Rivers, CA Performance Indicators
Flow criteria met at…
Oroville (150,000 cfs), New Bullard’s Bar (50,000 cfs)
Yuba City, Marysville (180,000 cfs)
Feather + Yuba Confluence (300,000 cfs)
Expected Annual Flood Damage ($)
Simulate for likely (little water) and unlikely events (lots of water)
Calculate damage for each event based on flows at downstream impact areas (HEC-FIA)
Weight by event likelihood and damage amount
Annualize to $ amount people pay every year
Reliability, Vulnerability, and Resilience to meet water demand (%)
CEE 6490

14. Relative Expected Annual Damages for Oroville & New Bullard’s Bar Storage Reallocations

15. Relative Expected Annual Damage for Reservoir Re-Operations Alternatives

16. Feather and Yuba Rivers, CA Primary Findings
Storage reallocations have small influence on EAD
Lowering flow objective to 270,000 cfs at Feather-Yuba confluence is most promising re-operation alternative
Up to 200 TAF storage in Oroville serves little additional flood protection purpose
Oroville reallocations have greater EAD reduction benefit than New Bullard’s Bar reallocations
EAD extremely sensitive to flow at Marysville, Natomas, and levee failure stage at Natomas
(Rosenberg, 2003)
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17. Integrating concepts into reservoir simulation models

18. Reservoir Simulation Modeling Data Requirements
For WEAP, HEC-ResSim, HEC-5, Oasis, RiverWare, etc.
Time-series of inflows
Spatial configuration of inflows
Routing between model nodes
Reservoir locations and
Physical data: pool elevation-storage-area curves, evaporation and leak rates
Dam outlets: elevation-release capacity curves
Operations
Zones: elevations
Release rules and prioritization in each zone
CEE 6490

19. Reservoir Simulation Modeling Computational Requirements
Time step
Method to calculate change in storage
Finite difference
Modified Puls (level pool)
Are inflows, releases, etc. at beginning of time step or averaged over the time step?
Routing
Simple (constant discharge-storage; velocity-based)
Muskingum (variable discharge-storage; attenuation)
Hydraulic (unsteady flows, variable storage; wave and out-of-bank flow)
CEE 6490

20. Reservoir Simulation Modeling Performance Measures
Delivery-reliability
Firm yield
Max (or min) reservoir storage level
Max (or min) flows at a particular location
Hydropower generated
Costs of shortages
Economic revenues from (b) or (e)
Vulnerability
Resiliency
And many, many others
CEE 6490

21. Bear River Canal Company
Above Cutler
Cutler
Bear River Canal Company
New Cache
Example 1. What features must you add to your ILO-3 model to represent this reservoir system?
Box Elder County
Bird Refuge
Reservoir, proposed
Reservoir, existing
Urban Use
Ag. Use
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Wetland

22. References
Bower, B. T., Hufschmidt, M. M., and Reedy, W. W. (1966). "Operating procedures: their role in the design of water-resource systems by simulation analysis." Design of Water Resource Systems, A. Maass and e. al, eds., Harvard University Press, Hashimoto, T., Stedinger, J. R., and Loucks, D. P. (1982). "Reliability, Resiliency, and Vulnerability Criteria for Water Resource System Performance Evaluation." Water Resources Research, 18(1), Hirsch, R. M., Cohon, J. L., and ReVelle, C. S. (1977). "Gains from joint operation of multiple reservoir systems." Water Resources Research, 13(2), Labadie, J. W. (2004). "Optimal Operation of Multireservoir Systems: State-of-the-Art Review." Journal of Water Resources Planning and Management, 130(2), , Lund, J. R. (2000). "Derived power production and energy drawdown rules for reservoir." Journal of Water Resources Planning and Management-Asce, 126(2), , Lund, J. R., and Ferreira, I. (1996). "Operating Rule Optimization for Missouri River Reservoir System." Journal of Water Resources Planning and Management, 122(4), ,
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23. References (cont.)
Lund, J. R., and Guzman, J. (1999). "Derived Operating Rules for Reservoirs in Series or in Parallel." Journal of Water Resources Planning and Management, 125(3), , Palmer, R. N., Smith, J. A., Cohon, J. L., and ReVelle, C. S. (1982). "Reservoir management in Potomac River Basin." Journal of Water Resources Planning and Management, 108(1), Paredes, J., and Lund, J. R. (2006). "Refill and drawdown rules for parallel reservoirs: Quantity and quality." Water Resources Management, 20(3), , Rosenberg, D. E. (2003). "Simulating Cooperative Flood and Water Supply Operations for two Parallel Reservoirs on the Feather and Yuba Rivers, CA," Masters Thesis, University of California, Davis, Davis, California, Wurbs, R. A. (1993). "Reservoir System Simulation and Optimization Models." Water Resources Planning and Management, 119(4), , Yeh, W. W. G. (1985). "Reservoir Management and Operations Models: A State of the Art Review." Water Resources Research, 21(12),
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