Infiltration
StormShed3G™ supports three variations of infiltration. The primary variation
is simply a constant rate in inches per hour. The rate is applied to the wetted
surface area of the storage structure.
The second method based on an average saturated hydraulic conductivity. The
methodology is taken from The 2005 Washington State Department of Ecology Stormwater
Management Manual, Volume III, Section 3.3.8. Specifically, the saturated hydraulic
conductivity that StormShed3G is expecting is described in step 6, page 3-89 of the volume.
The third method is a further implementation of the procedure described in
Volume III. It allows users compute the saturated hydraulic conductivity (Ksat)
directly from soils logs.
The implementation of Ksat is a entirely based on the procedure described in
Volume III and is not repeated here.
Ranges of values for natural materials
Table of saturated hydraulic conductivity (K) values found in nature
Values are for typical fresh groundwater conditions — using standard values
of viscosity and specific gravity for water at 20°C and 1 atm.
| K (cm/s) | 10e2 | 10e1 | 10e0 | 10e-1 | 10e-2 | 10e-3 |
10e-4 | 10e-5 | 10e-6 | 10e-7 | 10e-8 | 10e-9 | 10e-10 |
|---|
| K (ft/day) | 10e5 | 10e4 | 10e3 | 10e2 | 10e1 | 10 |
10e-1 | 10e-2 | 10e-3 | 10e-4 | 10e-5 | 10e-6 | 10e-7 |
|---|
| Relative Permeability | Pervious | Semi-Pervious |
Impervious |
| Aquifer |
Good | Poor | none |
|---|
| Unconsolidated Sand & Gravel |
Well Sorted Gravel |
Well Sorted Sand or Sand & Gravel |
Very Fine Sand, Silt, Loess, Loam |
|
|---|
| Unconsolidated Clay & Organic | |
Peat | Layered Clay |
Fat / Unweathered Clay |
|---|
| Consolidated Rocks | Highly Fractured Rocks |
Oil Reservoir Rocks | Fresh Sandstone |
Fresh Limestone, Dolomite | Fresh Granite |
|---|
Source: modified from Bear, 1972