Soils Data Fields (SWMM)
Infiltration parameters for soils can be edited on either the Soil Grid Window of the Subcatchments Grid or the Soil Property Sheet.
This table describes all the data fields used to define the infiltration parameters for soils.
Fields that are common to the majority of objects can be found in the Common Fields topic.
Soil Data
Database Table Name: sw_soil
Field Name 
Help Text 
Database Field 
Size 
Precision 
Default 
Error Lower Limit 
Error Upper Limit 
Warning Lower Limit 
Warning Upper Limit 


Soil ID 
The unique name that is used to identify this soil. 
id 
Text 
254 

0 





Initial infiltration 
Used by the Horton Infiltration model. Initial infiltration () from the equation to calculate rate:

initial_infiltration  Double  I  3  76.2  0  
Limiting infiltration 
Used in the Horton Infiltration model. Limiting infiltration () from the equation to calculate rate:

limiting_infiltration  Double  I  3  12.7  0  
Decay factor 
Used in the Horton Infiltration model. The infiltration rate decay constant for the Horton curve (1/hours). Typical values range between 2 and 7. 
decay_factor  Double  HR  3  4  
Maximum infiltration volume 
Used in the Horton Infiltration model. Maximum infiltration volume possible. 
max_infiltration_volume  Double  RD  3  0  0  
Average capillary suction 
Used by the Green Ampt model. The average value of soil capillary suction. 
average_capillary_suction  Double  RD  1  76.2  0  
Saturated hydraulic conductivity 
Used by the Green Ampt model. Soil saturated hydraulic conductivity. 
saturated_hydraulic_conductivity  Double  R  1  76.2  0 




Initial moisture deficit 
Used by the Green Ampt model. The fractional difference between soil porosity and actual moisture content. 
initial_moisture_deficit  Double  2  0  1  
Curve number 
Used by the Curve Number model. The SCS number of the curve associated with this subcatchment. A list of curve number values that can be used can found here. 
curve_number  Double  2  3  0  100  
Drying time 
Used in the Horton Infiltration and Curve Number models. Time in days for a fully saturated soil to dry completely. Typical values range from 2 to 14 days. 
drying_time  Double  TD  3  7 