river sediment calibration rules
DESCRIPTION
River Sediment Calibration Rules. Gary Shenk 5/3/05 Modeling Subcommittee. Schedule. Sediment calibration must be done by June 1. Nutrient Calibration must be done by August 1. Refinements will follow over the next 18 months. Calibration Method. Flow - PowerPoint PPT PresentationTRANSCRIPT
River Sediment Calibration Rules
Gary Shenk
5/3/05
Modeling Subcommittee
Schedule
• Sediment calibration must be done by June 1.
• Nutrient Calibration must be done by August 1.
• Refinements will follow over the next 18 months.
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 will apply
them by hand
critz
w
eMass
1
1
River Cohesive Sediment Simulation
SuspendedSediment
Bed Storage(unlimited)
Outflow
Sco
ur
Dep
osit
ion
Inflow
1*
crit
AreaM
critz
w
eMass
1
1
River Sediment Simulation
Bed Storage(unlimited)
Dep
osit
ion
River Sediment Simulation
Bed Storage(unlimited) S
cour
1*
crit
AreaM
River Sand Simulation
Jvelocityksand }{*][
Adjustments are then made to the bed depth
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
Uncalibrated
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
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
Stau 99Ctau 96SW .001CW .0001CM = 1SM = 1KS = 3ES = 3
Reduce the frequency of scour to deal with over-simulation
Stau 99Ctau 96SW .001CW .0001CM = .5SM = .5KS = 3ES = 3
Reduce the effect of scour to deal with over-simulation
Stau 99.5Ctau 98SW .001CW .0001CM = .5SM = .5KS = 2.8ES = 3
Tighten up the simulation
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.
‘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
I
Reported Error
Stau 97Ctau 93SW .001CW .0001CM = 1SM = 1KS = .003ES = 4
Starting point
Stau 97Ctau 93SW .001CW .0001CM = 1SM = 1KS = 3ES = 3
Sand Calibration
Stau 99Ctau 96SW .001CW .0001CM = 1SM = 1KS = 3ES = 3
Reduce Frequency of Scour
Stau 99Ctau 96SW .001CW .0001CM = .5SM = .5KS = 3ES = 3
Reduce effect of scour
Stau 99.5Ctau 98SW .001CW .0001CM = .5SM = .5KS = 2.8ES = 3
Tighten up calibration
paired daily values of flow X conc
0
1
2
3
4
5
6
7
8
0 1 2 3 4 5 6 7 8
simulated load
ob
serv
ed lo
ad
obs load
1:01
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
Plan
• Following calibration rules, team will calibrate all stations this month.– Jing Wu – Susquehanna– Jason Pope – Southern Rivers– ICPRB – Potomac
• Set up nutrient calibration– Jeff Raffensperger – observed data and input– Gary Shenk – model simulation setup– CBP nutrient team – nutrient input data