Green-Ampt Infiltration Parameter Estimates
|
USDA
Soil Texture Classification |
Suction Head |
Saturated Hydraulic
Conductivity |
Initial Moisture Deficit |
|||
|
(in) |
(mm) |
(in/hr) |
(mm/hr) |
Moist Soil Climates ( |
Dry Soil Climates ( |
|
|
Sand
|
1.95 |
49.5 |
9.27 |
235.6 |
0.346 |
0.404 |
|
Loamy
Sand |
2.41 |
61.3 |
2.35 |
59.8 |
0.312 |
0.382 |
|
Sandy
Loam |
4.33 |
110.1 |
0.86 |
21.8 |
0.246 |
0.358 |
|
Loam
|
3.50 |
88.9 |
0.52 |
13.2 |
0.193 |
0.346 |
|
Silt
Loam |
6.57 |
166.8 |
0.27 |
6.8 |
0.171 |
0.368 |
|
Sandy
Clay Loam |
8.60 |
218.5 |
0.12 |
3.0 |
0.143 |
0.250 |
|
Clay
Loam |
8.22 |
208.8 |
0.08 |
2.0 |
0.146 |
0.267 |
|
Silty Clay Loam |
10.75 |
273.0 |
0.08 |
2.0 |
0.105 |
0.263 |
|
Sandy
Clay |
9.41 |
239.0 |
0.05 |
1.2 |
0.091 |
0.191 |
|
Silty Clay |
11.50 |
292.2 |
0.04 |
1.0 |
0.092 |
0.229 |
|
Clay
|
12.45 |
316.3 |
0.02 |
0.6 |
0.079 |
0.203 |
1. These values are estimates for SWMM applications where more detailed soils information is not available. There is significant variance in these values; laboratory and field testing, sensitivity analysis, and calibration may be employed to improve upon these estimates.
2. Typically use USDA SCS (now NRCS) Soil Survey to determine Soil Texture. In these surveys, Saturated Hydraulic Conductivity is reported as Permeability . Use the values reported in the soil survey for permeability for HYDCON, rather than the HYDCON values listed in the table above. In the absence of a soil survey or more reliable information, the values listed above may be used.
3. Synthesized from Handbook of Hydrology, D.R. Maidment, Editor in Chief, McGraw-Hill, Inc., 1993, pp 5.1-5.39.