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 Factors improving average or better than average infiltration are considered to promote a good
hydrologic condition. Poor hydrologic condition factors decrease infiltration and increase runoff.
Table 1.1.1. General SCS Runoff Curve Numbers for rural Lands Including Feed Lots
Runoff Curve Number2
Lane-Use
Surface-Condition
Soil Group A
Soil Group B
Soil Group C
Soil Group D
Fallow
0.22
77
86
91
94
Row Crop
Straight Row
0.05
67
78
85
89
Contoured
0.29
65
75
82
86
Small Grain
0.29
63
74
82
85
Legumes or
0.29
58
72
81
85
Rotation Meadow
Pasture3
Poor
0.01
68
79
86
89
Fair
0.15
49
69
79
84
Good
0.22
39
61
74
80
Permanent
0.59
30
58
71
78
Meadow
Woodland
0.29
36
60
73
79
Forest with Heavy
0.59
25
55
70
77
Litter
Farmsteads
0.01
59
74
82
86
Urban (21%-27%
Impervious
0.01
72
79
85
88
Surfaces)
Grass Waterway
1.00
49
69
79
84
Water
0
100
100
100
100
Marsh
0
85
85
85
85
Animal Lot
Unpaved
91
91
91
91
Paved
94
94
94
94
Roof Area
100
100
100
100
1
Source: Young et al. (1982a)
2
Source: US Department of Agriculture, Soil Conservation Service (1976). Values given are for Antecedent Moisture Condition II.
3
Pasture should be considered "poor" if it is heavily grazed with no mulch. "Fair" pasture has between 50% and 75% plant cover
and is moderately grazed. "Good" pasture is lightly grazed and has more than 75% plant cover.
1.1-4
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