*n = porosity of storage reservoir aggregate or effective porosity of void-producing structure system
*n = porosity of storage reservoir aggregate or effective porosity of void-producing structure system (with underdrain) or effective porosity of surface ponding depth and filter media depth combined (no underdrain)
*f' = design infiltration rate of the underlying native soil (m/h)
*f' = design infiltration rate of the underlying native soil (m/h)