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