A modification of the constant-head permeameter to measure saturated hydraulic conductivity of highly permeable media.
The saturated hydraulic conductivity (Ks) is a key characteristic of porous media, describing the rate of water flow through saturated porous media. It is an indispensable parameter in a broad range of simulation models that quantify saturated and/or unsaturated water flow. The constant-head permeameter test is a common laboratory method to determine Kson undisturbed soil samples collected from the field. In this paper we show that the application of this conventional method may result in a biasedKsin the case of highly permeable media, such as the top layer ofSphagnumpeat and gravel. Tubes in the conventional permeameter, that collect water under the sample, introduce a hydraulic head-dependent resistance for highly permeable media and result in an underestimation ofKs. We present a simple and low-budget alternative of the constant-head permeameter test that overcomes the disadvantages of conventional permeameters. The new method was successfully tested on intact highly permeable peatmoss collected from a northern peatland. •Conventional constant-head permeameters underestimateKsof highly permeable media due to flow resistance in tubing systems•We developed the low-resistance permeameter to overcome this disadvantage.•Testing of the low-resistance permeameter demonstrated no systematic bias and successful application for highly permeable media.
Wageningen University, Soil Physics and Land Management Group, Wageningen, The Netherlands; Wageningen University, Plant Ecology and Nature Conservation Group, Wageningen, The Netherlands; Wageningen University, Soil Geography and Landscape Group, Wageningen, The Netherlands.
Jelmer J
JJ
Nijp
Wageningen University, Soil Physics and Land Management Group, Wageningen, The Netherlands.
Klaas
K
Metselaar
Wageningen University, Plant Ecology and Nature Conservation Group, Wageningen, The Netherlands.
Juul
J
Limpens
Wageningen University, Soil Physics and Land Management Group, Wageningen, The Netherlands.
Harm P A
HP
Gooren
Wageningen University, Soil Physics and Land Management Group, Wageningen, The Netherlands; Monash University, School of Chemistry, Melbourne, Victoria 3800, Australia.
Sjoerd E A T M
SE
van der Zee
Compression; Laboratory method; Low-resistance permeameter; Peat; Permeability; Reynolds number; Soil physics; Sphagnum