predicting a suitable period trafficability using drainmod mohammed salahat guillermo carrillo...
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Predicting a suitable period trafficability using
DRAINMOD
Mohammed SalahatGuillermo Carrillo
Supervised by: Dr. Mohtar, R.
Problem statement
High water table affects trafficability
Trafficability is important for timely seedbed preparation, planting, harvesting, and other field operations
Predict best time for trafficability
Site of study Southeast Purdue Agricultural
Center (SEPAC)
Clermont silt loam soil, very poorly drained
Corn was planted from 1984 through 1993 with tillage
Three years of measured water table (from 1987 through 1989) were used to test the performance of DRAINMOD
Methodology Obtain the data DRAINMOD
Run sensitivity analysis, fixed drain spacing and depth
Perform calibration and validation analysis
Determine the best trafficability periods
Good trafficability if water table is deeper than 60cm
Sensitivity analysis
Vertical conductivity vs Water table
0
50
100
150
200
250
300
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014
vertical conductivity
Wa
ter
tab
le
Parameters Degree of sensibility
Spacing Sensitive
Saturated K Sensitive
Actual distance from surface Light sensitive
Thickness of the restricting layer Light sensitive
Drainage coefficient No sensitive
Initial depth Sensitive
Drain depth Sensitive
Effective radius No sensitive
Vertical conductivity Highly sensitive
Thickness of the restricting layer Light sensitive
Results:Calibration
-50
0
50
100
150
200
250
300
0 50 100 150 200 250 300 350 400
Day
Wa
ter
tab
le
Vs
Weahter C.1
Weahter C.2
Calibrated
Measured
-50
0
50
100
150
200
250
300
0 50 100 150 200 250 300 350 400
Day
Dra
inm
od
Ou
tpu
t
k241d130n
K0125
k282d130
k241
k171
Kv_5
Kv_8
Measured
-20
0
20
40
60
80
100
120
140
160
180
0 50 100 150 200 250 300 350 400
Day
Wa
ter
tab
le
Dra-Out-88 Measu-88
-20
0
20
40
60
80
100
120
140
160
180
0 50 100 150 200 250 300 350
Day
Wa
ter
tab
le
Dra-Out-89 Measu-89
Validation
Results continued…
DRAINMOD predicts acceptable trafficability periods
Recommended trafficability period is May-7 to Nov.-5 for the dry year, 1988
Recommended trafficability period is June-29 to Nov.-14 for the wet year, 1989
Conclusions
DRAINMOD doesn’t work efficiently for frozen conditions
DRAINMOD works better in dry years
More data and work is needed
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