"Saturated hydraulic conductivity" is the ease with which pores of a saturated soil transmit water. Formally, it is the proportionality coefficient that expresses the relationship of the rate of water movement to hydraulic gradient in Darcy's Law (a law that describes the rate of water movement through porous media). It is expressed in micrometers per second. To convert micrometers per second to inches per hour, multiply micrometers per second by 0.1417. The historical definition of "saturated hydraulic conductivity" is the amount of water that would move vertically through a unit area of saturated soil in unit time under unit hydraulic gradient.
Saturated hydraulic conductivity is used in soil interpretations. It is also known as Ksat.
Source: U.S. Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. Available online. Accessed 9/13/2012.