Derivation of the SCS-CN parameter S from linearized Fokker-Planck equation
The potential maximum retention, S, of the Soil Conservation Service Curve Number (SCS-CN) method (SCS, 1956) was derived for a large set of published infiltration data ranging from Plainfield sand to Yololight clay using the relations between psi (negative pressure) and theta (moisture content) and between K (hydraulic conductivity) and theta. The physical significance of S is explained using the diffusion term of the linearized, Fokker-Planck equation for infiltration, which relates S to the storage and transmission properties of the soil. The s-values exhibit a strong looped relationship with the initial moisture content, analogous to that for curve numbers for three antecedent moisture conditions. The variations of S in vertical infiltration is also explained and discussed.
Bibliogr. 56 poz.