Geology Reference
In-Depth Information
Table 10.2
Total runoff and total soil loss, measured (for the whole experiment) and predicted
by WEPP (modified from Garcia, 2001).
Runoff (l)
Soil loss (kg)
Segment
Measured
WEPP
Variation %
Measured
WEPP
Variation %
L20S1
8052.86
17,780.10
120.8 (
+
)
6.615
0.540
1125.1 (
−
)
L20S7
9114.33
21,871.27
140.0 (
+
)
16.628
17.747
6.7 (
+
)
L40S1
12,453.02
35,051.46
181.5 (
+
)
11.519
1.397
724.6 (
−
)
L40S7
13,467.72
43,644.78
224,1 (
+
)
31.534
69.453
120.8 (
+
)
L
=
Slope length (m); S
=
Slope steepness (%).
Soil loss (Measured and WEPP)
(kg)
80,000
Measured
WEPP
70,000
60,000
50,000
40,000
30,000
20,000
10,000
Fig. 10.2
Soil loss (kg):
comparison of measured
values and those predicted
by WEPP.
0,000
L20S1
L20S7
L40S1
L40S7
Segments
consistency, because in the four situations there
was a very similar trend.
hydraulic conductivity),
K
r
(rill erodibility) and
t
c
(critical shear stress) were compared with the
data generated by the WEPP model equations.
The data obtained from plots were used as input
to the WEPP model.
Six plots were established on a Distrofic Haplic
Cambisol (Inceptisol) to determine soil loss and
runoff, for five seasonal crops. The soil texture is:
51% sand, 8% silt and 41% clay. The model input
data were estimated for the same soil properties,
soil management and slope steepness conditions
of the experimental station.
Three simulations were generated to estimate
soil loss and runoff by WEPP. Estimate 1 used the
values of
K
i
,
K
r
,
10.3 Case Study 2: Prediction of Water Erosion
for Soil and Climatic Conditions in Viçosa
Municipality, Minas Gerais State
The aim of this application (Gonçalves, 2007) was
to assess soil and water losses on an experimental
station under natural rainfall, and to compare
these results with data obtained through the
equations generated by the WEPP model. The
values obtained experimentally for the soil
parameters
K
i
(inter-rill erodibility),
K
e
(effective
τ
c
and
K
e
obtained experimentally.
