Evaluation of a simple lysimeter-design modification to minimize sidewall flow

A common criticism of many soil lysimeter designs has been the existence of artificial flowpaths along the soil-wall interface. This artificial flow i s referred to as sidewall flow. A simple lysimeter-design modification was evaluated that utilizes annular rings to divert sidewall flow near the soil surface into the soil column to minimize the occurrence of sidewall flow a long the remainder of the column's length. A chloride-tracer experiment was used to evaluate the effectiveness of annular rings in minimizing sidewall flow in a mesoscale soil lysimeter (0.6 m in diameter and 1.83 m in height ). The tracer-experiment data showed that even though sidewall flow may not have been completely eliminated it was reduced to an undetectable level ba sed on chloride distributions and time domain reflectometry measurements. H owever, a delicate balance exists between minimizing sidewall flow and sign ificantly altering the natural water-flow dynamics when using annular rings . The simple design modification provides a means of using a disturbed colu mn of soil to evaluate models of solute transport, and to study preferentia l flow and contaminant mobility without concern for spurious data due to ar tificial flow along the soil-wall interface of the lysimeter. (C) 2000 Publ ished by Elsevier Science B.V. All rights reserved.