1

River Sediment Calibration Rules

Gary Shenk

6/7/05

Modeling Subcommittee

2

Schedule

• Sediment calibration completed

• Initial nutrient calibration by August 1.

• Refinements will follow over the next 18 months.

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Calibration Method

• Flow– Automatic calibration method developed

• Edge-of-Field Sediment– Automatic calibration method developed

• River Sediment– Two out of three ain’t bad– Developed calibration rules and applied them

by hand

4

critz

w

eMass

1

1

River Cohesive Sediment Simulation

SuspendedSediment

Bed Storage(unlimited)

Outflow

Sco

ur

Dep

osit

ion

Inflow

1*

crit

AreaM

5

critz

w

eMass

1

1

River Sediment Simulation

Bed Storage(unlimited)

Dep

osit

ion

6

River Sediment Simulation

Bed Storage(unlimited) S

cour

1*

crit

AreaM

7

River Sand Simulation

Jvelocityksand }{*][

Adjustments are then made to the bed depth

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Calibration Rules

• All rivers segments upstream of a calibration point have identical parameters

• For nested rivers, this applies only to rivers downstream of any upstream gages.

Remington

Robinson

Rappahannock

1

9

Uncalibrated

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Stau 97 percentileCtau 93SW .001 inches/secCW .0001 CM = 1 lb/ft^2/daySM = 1KS = .003 empiricalES = 4

High flow in the ballpark, but low flow is a problem. Lowest concentrations are mostly VSS, which is not yet simulated and are at LOD in the observed

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Stau 97Ctau 93SW .001CW .0001CM = 1SM = 1KS = 3ES = 3

To deal with the lack of VSS in the simulation, use SAND to make the low concentrations work out. This can be easily reversed when VSS are simulated

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Stau 99Ctau 96SW .001CW .0001CM = 1SM = 1KS = 3ES = 3

Reduce the frequency of scour to deal with over-simulation

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Stau 99Ctau 96SW .001CW .0001CM = .5SM = .5KS = 3ES = 3

Reduce the effect of scour to deal with over-simulation

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Stau 99.5Ctau 98SW .001CW .0001CM = .5SM = .5KS = 2.8ES = 3

Tighten up the simulation

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Issues with simulation

• Low values dominate the CFD, but they are not meaningful from:– A load standpoint– An accuracy of observation standpoint– Simulation standpoint (no VSS)

• Flow not perfectly calibrated– If peak is missed by a day, then the

concentration simulation should not match the observed.

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‘Windowed’ comparison

• If simulated or observed value is below 10 mg/l set it to 10 mg/l.

• Check simulation for 24 hours before and after observation and set simulated value to point closest to observation.

Of the highest observed and simulated peaks at all calibration stations, almost as many peaks occurred one day apart, but few occurred on two days apart

One day apart – 83% of the same day figure

Two days apart – 19% of the same day figure

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I

Reported Error

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Stau 97Ctau 93SW .001CW .0001CM = 1SM = 1KS = .003ES = 4

Starting point

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Stau 97Ctau 93SW .001CW .0001CM = 1SM = 1KS = 3ES = 3

Sand Calibration

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Stau 99Ctau 96SW .001CW .0001CM = 1SM = 1KS = 3ES = 3

Reduce Frequency of Scour

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Stau 99Ctau 96SW .001CW .0001CM = .5SM = .5KS = 3ES = 3

Reduce effect of scour

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Stau 99.5Ctau 98SW .001CW .0001CM = .5SM = .5KS = 2.8ES = 3

Tighten up calibration

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Other Considerations: Load 1:1 plot, error vs Shear stress, Load Frequency

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Choptank RiverLog Sediment Load (log kg/mo)

y = 0.7828x + 1.0642

R2 = 0.7312

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

3 3.5 4 4.5 5 5.5 6 6.5 7

Phase 5 Simulation log kg/mo

ES

TIM

AT

OR

log

kg

/mo

Comparison with Estimator Model

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Legend

P5 Calibration Stations

# of Observations

0 - 100

101 - 300

301 - 500

501 - 1000

1001 - 5000

50

80

12

8

14

164

# of Stations

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Plan

• Following calibration rules, team has calibrated all stations this month.– Jing Wu – Susquehanna, Coastal Plain,

Southern Rivers– Ross Mandel – Potomac, Patuxent, Choptank– Doug Moyer – James, Appomattox– Jason Pope – Rappahannock, York

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Hope for automation

• Separate out sections of the CFD– Low part: sand - VSS– Highest part: silt– Mid-high part: clay

• PEST– Few parameters– Short run time ~ 1-2 minutes