Surface Irrigation Advance Equation: Variation of Subsurface Shape Factor

The volume balance (VB) algebraic equations based on the power advance assumption (i.e., the time invariance of the subsurface shape factor) may deviate significantly from accurate VB numerical solutions. By systematic analysis of the accurate VB numerical solutions obtained using the Kostiakov infiltration formula, the behavior of the subsurface shape factor as a function of time is examined. A new equation describing the time variation of the...