A drainage experiment was conducted to determine the time-dependence of soil-water retention during drainage of a quasi-uniform column of Lakeland sand and similar columns to which phosphatic clay was added as an amendment or a layer. Phosphatic clay was observed to increase and prolong water retention in the soil. Saturated hydraulic conductivity of the column with soil amended with 5 percent phosphatic clay in the surface 30 cm was 13 cm/hr as compared to 25 cm/hr for the quasi-uniform column of Lakeland sand. Drainage from the column with a 1-cm-thick layer of phosphatic clay and the column with a 2-cm-thick layer of phosphatic clay aggregates was greatly restricted. The nonaggregated phosphatic clay layer provided nearly constant impedence to flow across the layer, whereas successive water desaturation of the larger pores in the layer aggregates resulted in a time-dependent impedence to water flow. At saturation the hydraulic conductivities of the aggregated and nonaggregated clay layers were calculated to be 5.0 and 0.8 cm/hr, respectively. Maximum hydraulic head gradients across the aggregated and nonaggregated clay layers were 4 and 13, respectively. Values of unsaturated hydraulic conductivity calculated from soil-water characteristic curves for the Lakeland sand and measured water-saturated hydraulic conductivity were in good agreement with values measured experimentally from the soil columns.