Water collection efficiency of wick samplers under steady state flow conditions

Abstract Wick samplers could be used for measurements of solute transport. Water collection efficiency of wick samplers, defined as the volume of water collected by a sampler divided by the water flux from the root zone, should be close to 100%. We used three wick samplers differing in wall height in Hydric Hapludands under constant rainfall intensity and examined the effects of the rainfall intensity and wall height on the water collection efficiency based on experimental data and a numerical analysis. The water collection efficiency of wick samplers increased with the rainfall intensity and wall height because the increase in both rainfall intensity and wall height resulted in a distribution of the total potential inside the wick sampler close to that outside the wick sampler. Furthermore, the ratio of the cross-sectional area of the drain hole to that of the cylinder must be taken into account in the design of a wick sampler.