Many projects have stormwater or on-site septic issues that require a designer to know the soil infiltration and or soil permeability rates.
Many instruments such as the compact constant head permeameter shown in this photo can be used to obtain values of water movement into and through the soil.
On-site measurements can be much more valuable to designers than published data for given soil types. Soil Scientists can assist in obtaining and interpreting soil hydraulic conductivity measurements.