Boundary Flow in Laboratory Permeameters Used To Stimulate Recharge by Cyclic Water Spreading

Abstract

The contribution of boundary flow to the hydraulic conductivity values obtained from laboratory permeameters employed in cyclic flood‐dry infiltration studies was evaluated. Hydraulic conductivity in the boundary zone was less than that of the inner matrix for a 2‐mm sand. Conversely, the flow rate was greatest in the boundary zone for the finer textured sandy loam soils. The divergence between the hydraulic conductivity of the inner zone and the boundary zone was greatest during the first flooding period. For both matrix zones, the changes in hydraulic conductivity within a flood cycle and with a number of flood cycles, although of different magnitude, tended to be similar and parallel. A laboratory permeameter design is presented to facilitate partitioning the relative contributions of flow in the boundary and inner zones on the hydraulic conductivity values of soils.