DRAINMOD APPLICATION

ABE 527 Computer Models in Environmental and

Natural Resources

Review

drainage design…

soil water characteristic…

hourly rainfall, daily max & min temperature

relative yield input data set

Note: A DRAINMOD hydrology simulation can be run without specifying a relative yield input data set.

Objectives

After this lecture, you should get familiar with DRAINMOD application as for:

• How to input your own data to DRAINMOD required format;• What to consider for calibration purpose; and• How to use the model to predict subsurface drain flow, water table depth, and crop yield.

for different drain spacings.

Soil: Clermont silt loam soil

Slope: <1%; and land-leveled after

drain installation

Area: 6.2 ha

Southeast Purdue Agriculture Center Drainage Field (SEPAC)

Monitoring: Subsurface drain flow

Water quality samples

- Hourly rainfall

- Daily maximum and minimum temperatures

(measured on site or from nearby stations)

Model Inputs

- Hourly rainfall

- Daily maximum and minimum temperatures

Model Inputs

- Drainage design parameters

Model Inputs

Drain spacing, L 5 m 10 m 20 m 40 mDrain depth, b 75 cm 75 cm 75 cm 75 cm

Effective radius, re1.1 cm 1.1 cm 1.1 cm 1.1 cm

Distance from surface to restricting layer, h 120 cm 120 cm 120

cm120 cm

Maximum surface storage, Sm1.0 cm 1.0 cm 1.0 cm 1.0 cm

Note: parameter to be calibrated—Surface micro storage S1

- Soil properties: soil water characteristic, saturated hydraulic conductivity

Model Inputs cont.

Note: parameters to be calibrated— lateral Ksat; volumetric moisture at 0 cm tension; and the vertical hydraulic conductivity of the restrictive layer

- Crop parameters

Model Inputs cont.

Month Day Root depth (cm)1 1 3.04 25 3.05 14 9.05 27 18.06 1 19.56 20 24.07 24 30.08 20 30.09 2 30.09 24 18.09 25 3.0

12 31 3.0

Time distributions of effective rooting depths

Calibration Procedure1. Choose most uncertain parameters to be

calibrated

Range of parameter needed to be calibrated

 Volumetric soil moisture

at 0 m tension (cm3/cm3)

Layer RangeLayer 1 (0-25 cm) 0.389-0.46

Layer 2 (25-30 cm) 0.382-0.46

Layer 3 (30-120 cm) 0.405-0.46

Horizontal Ksat (cm/hr)Layer 1 (0-25 cm) 0.03-2

Layer 2 (25-30 cm) 0.03-0.65Layer 3 (30-120 cm) 0.05-0.67

Vertical Ksat of restrictive layer (cm/hr) 0.0005-0.003

Surface Micro storage S1 (cm) 0.3-1

m

Drain

Calibration Procedure cont.

2. Choose plot and year to be calibrated

Year Drain flow ratioW20/E20 W10/E10 W5/E5

1985 1.3 2.5 1.11986 2 2.3 1.71987 2 2 1.51988 1.8 2 1.11989 1.7 2.3 1.41990 2.1 2.3 1.21991 2.2 2.4 1.41992 3.1 2.4 1.91993 1.5 2.3 1.31994 1.6 1.9 1.61995 1.5 1.5 1.21996 1.5 1.9 1.31997 1.8 2.1 1.31998 1.5 2 1.41999 1.7 1.6 1.1

--West block and east block need to be calibrated separately. --W20 and E20 in 1988-1989 were chosen.

Range of parameter needed to be calibrated

 Volumetric soil moisture

at 0 m tension (cm3/cm3)

Layer Range

Layer 1 (0-25 cm) 0.389-0.46

Layer 2 (25-30 cm) 0.382-0.46

Layer 3 (30-120 cm) 0.405-0.46

Horizontal Ksat (cm/hr)

Layer 1 (0-25 cm) 0.03-2

Layer 2 (25-30 cm) 0.03-0.65

Layer 3 (30-120 cm) 0.05-0.67

Vertical Ksat of restrictive layer (cm/hr) 0.0005-0.003

Surface Micro storage (cm) 0.3-1

n

ii

n

iii

n

ii

OO

OPOOEF

1

2

1

2

1

2

%100

1

11

n

ii

n

ii

n

ii

O

OP

APE

Calibration Objective Functions(1) Nash-Sutcliffe efficiency:

(2) Absolute percent error:

22 )5.0()1( APEEFFagg

Aggregated function, combining (1) and (2):

Automatic CalibrationParameter values against model Nash-Sutcliffe efficiencies

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.05 0.15 0.25 0.35 0.45 0.55 0.65KsatH3

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.03 0.13 0.23 0.33 0.43 0.53 0.63

KsatH2

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.03 0.33 0.63 0.93 1.23 1.53 1.83KsatH1

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0005 0.001 0.0015 0.002 0.0025 0.003KsatV

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0S1

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.389 0.409 0.429 0.449W1

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.382 0.402 0.422 0.442W2

Nas

h-S

utc

liffe

Eff

icie

nc

y

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.405 0.415 0.425 0.435 0.445 0.455W3

Nas

h-S

utc

liffe

Eff

icie

nc

y

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Relative absolute percent error

Nash

-su

tcliff

e e

ffic

ien

cy

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 2 4 6 8 10 12 14 16 18 20

Sumulation ranked by EF values

Ab

so

lute

percen

t erro

r

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Nash

-Su

tcliff

e e

ffic

ien

cy

0.11

0.008 0.018 0.004

0.796 0.780 0.778 0.773

0.554 0.563 0.552

EF

Fagg

APE

0.643

Identify Optimum Parameter Set 22 )5.0()1( APEEFFagg

0.0

0.3

0.6

0.9

1.2

1.5

1.8

2.1

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Julian Date

Drai

nflo

w (c

m/d

ay)

Observed

Predicted

Representative observed and predicted drain flow graph

Observed and predicted water table graph

Predicted and observed relative yields

30

40

50

60

70

80

90

100

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999Year

Rel

ativ

e Y

ield

(%

)

Obs_5 m Obs_10 m Obs_20 m Obs_40 mPre_5 m Pre_10 m Pre_20 m Pre_ 40 m

SUMMARY

Nash-Sutcliffe efficiency (EF) for daily drain flow ranging from -0.66 to 0.81;

EF for water table depth from -0.66 to 0.9;

Statistical tests of EF indicating insignificant difference among the three drain spacings;

Both observed and predicted relative yields indicating yields decreasing with the increase of drain spacing;

Average percent errors ranging from 1.3 to 9.7% for corn yield and from -0.8 to 10.3% for soybean yield.