Designs for Disc Permeameters

Abstract

Disc permeameters are designed to measure hydraulic properties of field soils containing macropores and preferential flow paths and are particularly useful in soil management studies. We present here designs for disc permeameters for both positive and negative water supply heads. The effects of the water supply membrane and soil contact material on permeameter performance are examined using approximate quasi‐analytic solutions to the flow equation. This analysis provides approximate criteria for the selection of membrane and soil contact materials. Limitations to performance caused by restricted air entry are considered and design criteria are given also. We present in situ tests of the disc permeameter for the early stages of one‐dimensional infiltration and an example of the deterministic variation of sorptivity of a field soil with supply potential. Finally, we use ponded and unsaturated sorptivities measured in situ with disc permeameters to find the saturated hydraulic conductivity and flow‐weighted mean characteristic pore dimension of a field soil.

A Review of Approaches for Measuring Soil Hydraulic Properties and Assessing the Impacts of Spatial Dependence on the Results

“…However, in most cases such methods require undisturbed soil samples and they cannot be easily transferred to the open field. More simple methods, as recently suggested, are based on measuring unconfined infiltration rates with a disc permeameter (Perroux and White, 1988;Watson and Luxmoore, 1986;Ankeny et al, 1991) or a surface crust to restrict flow rates into the soil (Booltink et al, 1991). By offering slight hydraulic resistance to water movement, discs and crusts allow a water supply potential h to be applied at the soil surface, with a negligible head loss.…”

“…Following the design of Perroux and White (1988), a permeameter ( Figure 22) was set up by the Hydrology laboratory of the Dept. DITEC, University of Basilicata, Italy.…”

“…The theoretical foundations for using a disk permeameter to infer soil hydraulic properties have been discussed in detail elsewhere (Perroux and White, 1988;Smettem and Clothier, 1988). Only the salient features are recalled below:…”

Infiltração da água no solo no sistema pedológico Campus do Arenito, cidade gaúcha, noroeste do estado do Paraná

“…Essa análise permite caracterizar o fluxo de água no interior do solo, distinguindo a infiltração dos grandes poros (biológicos ou interagregados) daquela que ocorre na matriz do solo (Perroux & White, 1988). Mathieu & Pieltain (1998), concordando com esse método, também o adaptaram ao estudo da variabilidade espacial das propriedades de infiltração.…”

Infiltration performance of engineered surfaces commonly used for distributed stormwater management

“…Disk infiltrometers provide a constant positive or negative head at the surface. The cumulative infiltration record can be analyzed to determine the short term effects of sorptivity and the long term, steady state infiltration capacity at the field conditions (Wooding, 1968;Perroux & White, 1988). Unsaturated hydrophilic porous media typically exhibits early time dominance of processes contributing to sorptivity, followed by a decline in infiltration rate as the distance to the axisymmetric wetting front increases and the permeability of the field saturated media at the applied head is approached.…”