WATER TEMPERATURE MODEL FOR BRANCHED RIVER SYSTEMS
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1-Dimensional, Time Dependent 1-Dimensional, Time Dependent
Advection only Daily or Hourly Simulations Energy Budget Method
Mixed Lagrangian-Eulerian solution technique Reverse Particle
Tracking Mixed Lagrangian-Eulerian solution technique Reverse
Particle Tracking Reduces error due to numerical dispersion Reduces
problems of numerical instability Scaleable in time and space
FORTRAN (plain vanilla) FORTRAN (plain vanilla) RBM10 Model
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dT dt = q surf A r C p + e CHANGE IN ENERGY SURFACE ENERGY
EXCHANGE ONE-DIMENSIONAL ENERGY BUDGET MATHEMATICAL MODEL MODEL
ERROR
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REVERSE PARTICLE TRACKING
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Elements of RBM10 Framework Boundaries of Simulated System
Boundaries of Simulated System System Topology System Topology
Geometry/Hydrodynamics Geometry/Hydrodynamics Boundary Inputs (Flow
and Temperature) Boundary Inputs (Flow and Temperature) Heat Budget
Inputs based on Meteorology Heat Budget Inputs based on
Meteorology
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Dworshak
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Geometry/Hydrodynamics Mainstem Geometry for Impounded Reaches
Mainstem Geometry for Impounded Reaches - Storage reservoirs with
variable elevation - Volume-elevation relationships are used to
vary geometry of model elements Velocity Velocity -Continuity: V =
Flow / X-Area
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Geometry/Hydrodynamics Mainstem Geometry for Free-Flowing
Reaches Varies Depending on Flow Mainstem Geometry for Free-Flowing
Reaches Varies Depending on Flow Need cross-sectional profiles of
the river bottom Open channel hydraulics relationships HEC-RAS
model gradually varied flow is assumed gradually varied flow is
assumed provides cross-sectional area and top width over the range
of observed flows provides cross-sectional area and top width over
the range of observed flows area used to estimate velocity, width
used to estimate surface area for heat exchange area used to
estimate velocity, width used to estimate surface area for heat
exchange
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Meteorological Data Needed to Compute Heat Budget Air
Temperature Dew Point Wind Speed Atmospheric Pressure Cloud
Cover
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Issues Issues Mainstem Temperature Monitoring Monitoring at
Dams Not Designed for Assessment of River Temperature Monitoring at
Dams Not Designed for Assessment of River Temperature Limited
Quality Control/Quality Assurance Limited Quality Control/Quality
Assurance Tributary Temperature Monitoring Discontinuous Record
Discontinuous Record Unknown Quality Control/Quality Assurance
Unknown Quality Control/Quality Assurance Meteorology Limited
Geographical Coverage Limited Geographical Coverage Data
Limitations
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SOME SOURCES OF UNCERTAINTY
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Meteorology Meteorology Described by five regional weather
stations Mainstem Flow Mainstem Flow Leopold equations developed
from gradually-varied flow methods for un-impounded reaches
Tributary Temperatures Tributary Temperatures Non-linear
regressions developed from local air temperature and weekly/monthly
river temperatures Numerical Scheme Some numerical dispersion Some
numerical dispersion Conservation of mass/energy (?) Conservation
of mass/energy (?)
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PARAMETER ESTIMATION
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Parameters Parameters evaporation rates assignment of area
covered by 5 meteorological stations Model uncertainty PARAMETER
ESTIMATION
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MODEL EVALUATION AND TESTING
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Columbia River Statistics (1995-1999)) Mean Difference Standard
Deviation Location Snake @ Ice Harbor -0.18 1.07 Columbia @
Bonneville -0.391.33
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Mean Difference Standard Deviation Location Fraser River @
Hells Gate -0.02 0.49 Fraser River Statistics (1998)
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SOME APPLICATION OUTSIDE THE ENVELOPE
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DISPERSI VE
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TWO-DIMENSIONAL
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MODEL APPLICATION
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Impact of Dams on Natural Condition Two scenarios are run using
identical boundary inputs (weather, tributary flows/temperatures,
etc.) Two scenarios are run using identical boundary inputs
(weather, tributary flows/temperatures, etc.) 1. Existing Condition
2. Un-impounded Condition Dams are mathematically removed altered
geometry Dams are mathematically removed altered geometry
Corroboration not feasible no observations Corroboration not
feasible no observations Un-impounded Condition is not the natural
condition model domain does not reach to headwaters Un-impounded
Condition is not the natural condition model domain does not reach
to headwaters
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Impact of Individual Dams on Daily Cross Sectional Average
Temperature in the Columbia River
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PREDICTED AND OBSERVED TEMPERATURES IN THE SNAKE AND COLUMBIA
RIVERS USING METEOROLOGY GENERATED FOR VIC
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SIMULATED TEMPERATURES IN THE SNAKE AND COLUMBIA RIVERS FOR
THREE CLIMATE CHANGE SCENARIOS
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The End
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Impact of Point Sources on Mainstem Temperatures Simulated
Increases in Temperature at River Mile 42 in the Columbia River due
to the Existing Point Sources
