18
2 Similarity of Model Experiments
1
3
2
4
5
7
9
10
15
11
8
6
16
13
14
12
Fig. 2.4 Landscape simulator for the Model Da in which the rainfall simulation experiments were
conducted. All units are in meters. Keys: 1. Constant head tank; 2. Immersed pump; 3. Branch pipe;
4. Valve; 5. Flow-meter; 6. Water supply pipe; 7. Rainfall generator; 8. Bracket; 9. Plastic screen;
10. Haul line; 11. Model landform; 12. Collecting ditch; 13. Drainage hole; 14. Bucket gauge; 15.
Tail pipe; 16. Plug
The erodible material was passed through a 1 cm sieve to remove large clods, debris
and grassroots. The basic properties of the loess are shown in Table 2.2. The 50%
diameter of the soil particles d 50 was 52.2 µm, and specific gravity, γ s , was 2.56.
However, in order to moderate the anti-erosion properties of the land cover in the
Model Db, about 1/3 in volume of fine sand was mixed evenly with the loess, and
some pre-designed rills were cultivated on the slopes.
An open-book-type watershed designed based on the landforms in the Yangdaogou Catchment in the 1960s, was used to represent the initial conditions for landscape
development. To ensure a regular and original microtopography, the soil was prepared by hand patting to generate a ‘smooth’ roughness. A permeable trough base
was used to allow free drainage of infiltrated water.
Table 2.2 Soil particle size
distribution in the models
Particle
diameter
(mm)
*Cumulative
weight (%)
Particle
diameter
(mm)
*Cumulative
weight (%)
0.005
7.2
0.175
99.5
0.0125
22.2
0.35
99.8
0.0375
53.4
0.7
100.0
0.0875
96.5
*The cumulative weight is the percentage of the total weight of
particles with diameters less than the diameter to the total weight
of the sand samples listed in the same column
2 Similarity of Model Experiments
1
3
2
4
5
7
9
10
15
11
8
6
16
13
14
12
Fig. 2.4 Landscape simulator for the Model Da in which the rainfall simulation experiments were
conducted. All units are in meters. Keys: 1. Constant head tank; 2. Immersed pump; 3. Branch pipe;
4. Valve; 5. Flow-meter; 6. Water supply pipe; 7. Rainfall generator; 8. Bracket; 9. Plastic screen;
10. Haul line; 11. Model landform; 12. Collecting ditch; 13. Drainage hole; 14. Bucket gauge; 15.
Tail pipe; 16. Plug
The erodible material was passed through a 1 cm sieve to remove large clods, debris
and grassroots. The basic properties of the loess are shown in Table 2.2. The 50%
diameter of the soil particles d 50 was 52.2 µm, and specific gravity, γ s , was 2.56.
However, in order to moderate the anti-erosion properties of the land cover in the
Model Db, about 1/3 in volume of fine sand was mixed evenly with the loess, and
some pre-designed rills were cultivated on the slopes.
An open-book-type watershed designed based on the landforms in the Yangdaogou Catchment in the 1960s, was used to represent the initial conditions for landscape
development. To ensure a regular and original microtopography, the soil was prepared by hand patting to generate a ‘smooth’ roughness. A permeable trough base
was used to allow free drainage of infiltrated water.
Table 2.2 Soil particle size
distribution in the models
Particle
diameter
(mm)
*Cumulative
weight (%)
Particle
diameter
(mm)
*Cumulative
weight (%)
0.005
7.2
0.175
99.5
0.0125
22.2
0.35
99.8
0.0375
53.4
0.7
100.0
0.0875
96.5
*The cumulative weight is the percentage of the total weight of
particles with diameters less than the diameter to the total weight
of the sand samples listed in the same column