|Material||Porosity (%)||Typical Conductivity (m/hr)|
|40 - 55||<1<0.1|
|Sand||35 - 50||5 - 50|
|Gravel / Crushed Stone||10 - 30||50 - 250500|
|Porous Concrete||10 - 30||200 50 - 300500|
|Rubber (Shredded)||40 - 50||300+|
|Crates/Lined tank||90 - 100100 - 1000||500+|
Conductivity and Porosity values of a Soil can vary widely between sites. You may need help from a Geotechnical Engineer for evaluating the appropriate values on your site.
Note that the Porosity of a Clay can be larger than that of a Sand, but the Drainable Porosity of the Clay is much lower than that of the Sand, because the Field Capacity of the Clay is much higher than that of a Sand.
Therefore a soil layer with a significant content of Clay can only be represented properly using the Soil layer (Filtration Layers tab), where the Field Capacity and Wilting Point values can be specified.