Land Sediment Calibration Final results Modeling Subcommittee 5/3/05
Jan 12, 2016
Land Sediment Calibration
Final results
Modeling Subcommittee
5/3/05
Sediment Pathway in Phase 5
BMP Factor
Land Acre FactorDelivery Factor
Edge of Field
Edge of Stream
In Stream Concentrations
Total13 land uses for sediment simulation
• Forest • Harvested Forest• Natural grass• Extractive• Barren• Pervious Urban• Impervious Urban
• Pasture• Bad Pasture• Hay• High till with manure• High till no manure• Low till with manure
Agriculture Other
Needed EOF targets for 13 land uses
• Pasture => Pasture• Bad Pasture => 9.5 * Pasture• Hay => 1/3 Crop (P4 NRI)• High till with manure => 1.25 * Crop• High till no manure => 1.25 * Crop• Low till with manure => 0.75 * Crop
Agriculture - NRI gave estimates of Pasture and Cropland for each county
Needed EOF targets for 13 land uses
• Forest => Use P4 NRI• Harvested Forest => Mean Forest * 10 = 3.4 t/ac/yr• Natural grass => Mean Pasture = 1.5 t/ac/yr• Bare => 40 t/ac/yr• Extractive => 10 t/ac/yr• Pervious Urban => 0.74 t/ac/yr• Impervious Urban => 5.18 t/ac/yr• Aeolian => 10 lb/ac/day
Other – targets estimated from literature or previous model values
Land Sediment Simulation
KSER
Detached Sediment
Soil Matrix(unlimited)
Wash off
Rai
nfal
lD
etac
hmen
t
Att
achm
ent
KRER AFFIXNVSI
Gen
erat
ion
4 parameters, 1 target
Rule 1 - Zero Detached Sed after Large Storms
Runoff, Washoff, and Sed Storage
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
3650 3670 3690 3710 3730 3750Days
wa
ter
(in
/d);
Se
d (
t/d
); S
ed
Sto
r (t
on
s)
surodetswssd
vanSickle and Beschta (1983)Allen Gellis (pers communication)
Decision Rules for Four Key land Parameters:
Rule2 – Detached Sediment Storage Reaches 90% of its Max in 30 Days
)1( *tAFFIXeAFFIX
NVSIS
SAFFIXNVSIdt
dS*
AFFIX = 0.07673
Detached Storage Vs Time
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 15 30 45 60 75 90
Day
Det
ach
ed S
tora
ge
Rule3 – Generation makes up significant portion of
Detached Sediment
• NVSI = [significant fraction] * target load
Soil Matrix(unlimited)
Detached Sediment
Rai
nfal
lD
etac
hmen
t
KRERNVSI
Gen
erat
ion
Strategy: Reduce the Parameter Set
• Assume ratio of NVSI : EOF target
• Assume ratio of KSER : KRER
• Adjust KSER to meet target
• 20 scenarios formulated
- Ratio of NVSI : EOF Target picked from { 0.5, 1, 1.5, 2}
- Ratio of KSER:KRER picked from { 2, 5, 10, 15, 20}
Strategies to optimize ratios:
• Does the simulated EOF meet the target?
• Does the model correctly capture the dynamic of land process?
• Do the different land calibrations make a difference in the correlation between simulated and observed?
Iterative simulation results • Scenarios with KSER/KRER ratio > 5 could NOT
reach the targets for some of segments, particularly for Barren land
• Choices narrowed down to 8 scenarios
• Optimal scenario should have lower average dets and higher correlation
- Dynamic of land process Land segment A42033 - pasture, KSER/KRER = 5
Detached Storage goes down to zero sometimes
0
0.5
1
1.5
2
2.5
3
0 1000 2000 3000 4000 5000 6000 7000
suro
dets
wssd
0
0.4
0.8
1.2
1.6
2
0 100 200 300 400 500 600
suro
dets
wssd
Correlation of sediment concentrations for each of 8 scenarios
Different scenarios make little difference on the correlation of simulated and observed concentrations
Average detached storage for each of 8 scenarios
Average detached storage decrease with Decrease of NVSI ratio and Increase of KSER/KRER ratio
Final solution and Status
• AFFIX = 0.0765
• NVSI : EOF target = 1.5
• KSER : KRER = 5
• EOF calibration done two weeks ago
• Have used for river calibration since