Monitoring and Simulating 3-D Water Circulation at the Confluence of the Snake and Clearwater Rivers Christopher B Cook MC Richmond, MD Bleich, SP Titzler,

Monitoring and Simulating 3-D Monitoring and Simulating 3-D Water Circulation at the Confluence Water Circulation at the Confluence of the Snake and Clearwater Riversof the Snake and Clearwater Rivers

Monitoring and Simulating 3-D Monitoring and Simulating 3-D Water Circulation at the Confluence Water Circulation at the Confluence of the Snake and Clearwater Riversof the Snake and Clearwater Rivers

Christopher B CookMC Richmond, MD Bleich, SP Titzler, and B Dibrani

September 22, 2004Richland, WA

BPA Project 2002-027-00

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Snake and Snake and Clearwater R. Clearwater R. ConfluenceConfluence

Border of Border of WA and ID.WA and ID.

Snake and Snake and Clearwater R. Clearwater R. ConfluenceConfluence

Border of Border of WA and ID.WA and ID.

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Circulation Dynamics at the Confluence

Determined by discharge and density (primarily a function of temperature at this location).

Mixing processes can be: Observed by collecting field data. Modeled numerically. Approximated by examining the momentum balance

between the two rivers.

At Snake/Clearwater confluence, we’ve discovered four “modes” based upon Q ratio and temp delta (Δ).

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2003 Temperature Monitoring Locations

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2003 Temperature Logger Data2003 Temperature Logger Data Field data confirmed suspected large lateral Field data confirmed suspected large lateral

differences…differences…



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Site 5 a & b – Red Wolf Bridge

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Sites 6 & 7 – Confluence

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Site 8 a & b – Blue Bridge

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2003 Temperature Logger Data2003 Temperature Logger Data Unexpected: cold water migrating “upstream” Unexpected: cold water migrating “upstream”

2003 Temperature Logger Data2003 Temperature Logger Data Unexpected: cold water migrating “upstream” Unexpected: cold water migrating “upstream”

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Mode 1: April 4, 2002Mode 1: April 4, 2002Mode 1: April 4, 2002Mode 1: April 4, 2002

Upstream SnakeTemperature: 7.4°CDischarge: 829 m3/s

ClearwaterTemperature: 5.8°CDischarge: 746 m3/s

Temperature delta: 1.6°CS/C Discharge ratio: 1.1(~equal Q and T)

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Mode 2: May 23, 2003Mode 2: May 23, 2003Mode 2: May 23, 2003Mode 2: May 23, 2003



Temperature delta: 3.5°CS/C Discharge ratio: 1.4(high Q ratio, temp ~equal)

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Mode 3: July 21, 2002Mode 3: July 21, 2002Mode 3: July 21, 2002Mode 3: July 21, 2002



Temperature delta: 9.3°CS/C Discharge ratio: 0.9(large temp delta, Q ~equal)

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Typical pattern…Clearwater subducts under the Snake River.

Satellite Image 7/21/2002Temp delta = 9.3°C

Density Driven Flow

Colder Clearwater R flowed“upstream” along bottom of the Snake R.

“Upstream” motion halted when a balance of momentum was reached (density/gravity versus shear).

18 Degree Isotherm 20 Degree Isotherm

14 Degree Isotherm2018 °C16 14

2018 °C16 14

2018 °C16 14

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Mode 4: July 30, 2003Mode 4: July 30, 2003Mode 4: July 30, 2003Mode 4: July 30, 2003



Temperature delta: 11°CS/C Discharge ratio: 1.2(Larger Snake, large T delta)

Mode 5 would be large Clwtr,but not observed

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Summary Summary Summary Summary Mode 1 – equal Q & T

Mode 4 – larger S Q, large ΔTMode 2 – larger S Q, equal T

Mode 3 – equal Q, large ΔT

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3-D CFD Model of the Confluence3-D CFD Model of the Confluence3-D CFD Model of the Confluence3-D CFD Model of the Confluence

Applying Flow-3D, a commercial software package because: Large user base Previously tested/verified by PNNL & others.

Solves the 3-D RANS equations using a 2nd order finite-volume method. Several turbulence models available; currently using RNG.Physical domain is decomposed into 4 Cartesian blocks, which are composed of variable sized hexahedral cells. ~2M total cells used here.

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equal Q & large ΔT (Mode 3)equal Q & large ΔT (Mode 3)CFD ResultsCFD Results


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SummarySummarySummarySummary

Circulation dynamics are determined by: Ratio of discharge Density differences

Processes have been: Observed with temperature loggers Observed with ADCP (not shown) Observed with IR & visible band satellite images Simulated with 3-D CFD model

Momentum balance (mode) can now be predicted.

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Where are we going with this research?Where are we going with this research?Where are we going with this research?Where are we going with this research?

Response of anadromous salmonids and other aquatic species is being studied.

Patterns in the confluence can be produced by managing timing, quantity, and quality of upstream releases from DWK reservoir (Clearwater).

AcknowledgmentsAcknowledgmentsAcknowledgmentsAcknowledgments Bonneville Power Administration (Project 2002-027) U.S. Dept. of Energy, National Nuclear Security

Administration, MTI satellite imagery

Monitoring and Simulating 3-D Water Circulation at the Confluence of the Snake and Clearwater Rivers Christopher B Cook MC Richmond, MD Bleich, SP Titzler,

Documents

equal slide

upstream slide

m3s clearwater temperature

upstream snake temperature

large t slide

m3s temperature delta

c sc discharge ratio

function of temperature