Two- and three-dimensional infiltration: Seepage from irrigation channels and infiltrometer rings

Abstract

The steady seepage rates at large times from flat-bottomed channels and channels of semi-circular cross-section were determined in laboratory tank experiments using various sands. Good agreement was found with the theoretical relationships which assume the flow to be confined to a saturated region bounded by a capillary-fringe surface and to be uniform and vertical at great depths. The steady large-time seepage rates were also obtained in laboratory sand-tank experiments for the three-dimensional cases of seepage from circular shallow ponds and hemispherical sources. These agreed with relationships obtained using an electrolytic tank analogue with approximate boundary conditions assumed for the flow region. A method of analysis of large-time seepage measurements from irrigation channels and infiltrometer rings is proposed, which yields the hydraulic conductivity and pressure head at the wetting front from experiments with different size channels or rings.